Publications by authors named "Laurie Marczak"

23 Publications

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Prevalence and intensity of soil-transmitted helminth infections of children in sub-Saharan Africa, 2000-18: a geospatial analysis.

Lancet Glob Health 2021 01;9(1):e52-e60

Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK.

Background: Driven by global targets to eliminate soil-transmitted helminths as a public health problem, governments have rapidly rolled out control programmes using school and community-based platforms. To justify and target ongoing investment, quantification of impact and identification of remaining high-risk areas are needed. We aimed to assess regional progress towards these targets.

Methods: We did a continental-scale ecological analysis using a Bayesian space-time hierarchical model to estimate the effects of known environmental, socioeconomic, and control-related factors on the prevalence of soil-transmitted helminths, and we mapped the probability that implementation units had achieved moderate-to-heavy intensity infection prevalence of less than 2% among children aged 5-14 years between Jan 1, 2000, and Dec 31, 2018.

Findings: We incorporated data from 26 304 georeferenced surveys, spanning 3096 (60%) of the 5183 programmatic implementation units. Our findings suggest a reduction in the prevalence of soil-transmitted helminths in children aged 5-14 years in sub-Saharan Africa, from 44% in 2000 to 13% in 2018, driven by sustained delivery of preventive chemotherapy, improved sanitation, and economic development. Nevertheless, 1301 (25%) of 5183 implementation units still had an estimated prevalence of moderate-to-heavy intensity infection exceeding the 2% target threshold in 2018, largely concentrated in nine countries (in 1026 [79%] of 1301 implementation units): Nigeria, Democratic Republic of the Congo, Ethiopia, Cameroon, Angola, Mozambique, Madagascar, Equatorial Guinea, and Gabon.

Interpretation: Our estimates highlight the areas to target and strengthen interventions, and the areas where data gaps remain. If elimination of soil-transmitted helminths as a public health problem is to be achieved in sub-Saharan Africa by 2030, continued investment in treatment and prevention activities are essential to ensure that no areas are left behind.

Funding: Bill & Melinda Gates Foundation.
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http://dx.doi.org/10.1016/S2214-109X(20)30398-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7786448PMC
January 2021

Mapping 123 million neonatal, infant and child deaths between 2000 and 2017.

Authors:
Roy Burstein Nathaniel J Henry Michael L Collison Laurie B Marczak Amber Sligar Stefanie Watson Neal Marquez Mahdieh Abbasalizad-Farhangi Masoumeh Abbasi Foad Abd-Allah Amir Abdoli Mohammad Abdollahi Ibrahim Abdollahpour Rizwan Suliankatchi Abdulkader Michael R M Abrigo Dilaram Acharya Oladimeji M Adebayo Victor Adekanmbi Davoud Adham Mahdi Afshari Mohammad Aghaali Keivan Ahmadi Mehdi Ahmadi Ehsan Ahmadpour Rushdia Ahmed Chalachew Genet Akal Joshua O Akinyemi Fares Alahdab Noore Alam Genet Melak Alamene Kefyalew Addis Alene Mehran Alijanzadeh Cyrus Alinia Vahid Alipour Syed Mohamed Aljunid Mohammed J Almalki Hesham M Al-Mekhlafi Khalid Altirkawi Nelson Alvis-Guzman Adeladza Kofi Amegah Saeed Amini Arianna Maever Loreche Amit Zohreh Anbari Sofia Androudi Mina Anjomshoa Fereshteh Ansari Carl Abelardo T Antonio Jalal Arabloo Zohreh Arefi Olatunde Aremu Bahram Armoon Amit Arora Al Artaman Anvar Asadi Mehran Asadi-Aliabadi Amir Ashraf-Ganjouei Reza Assadi Bahar Ataeinia Sachin R Atre Beatriz Paulina Ayala Quintanilla Martin Amogre Ayanore Samad Azari Ebrahim Babaee Arefeh Babazadeh Alaa Badawi Soghra Bagheri Mojtaba Bagherzadeh Nafiseh Baheiraei Abbas Balouchi Aleksandra Barac Quique Bassat Bernhard T Baune Mohsen Bayati Neeraj Bedi Ettore Beghi Masoud Behzadifar Meysam Behzadifar Yared Belete Belay Brent Bell Michelle L Bell Dessalegn Ajema Berbada Robert S Bernstein Natalia V Bhattacharjee Suraj Bhattarai Zulfiqar A Bhutta Ali Bijani Somayeh Bohlouli Nicholas J K Breitborde Gabrielle Britton Annie J Browne Sharath Burugina Nagaraja Reinhard Busse Zahid A Butt Josip Car Rosario Cárdenas Carlos A Castañeda-Orjuela Ester Cerin Wagaye Fentahun Chanie Pranab Chatterjee Dinh-Toi Chu Cyrus Cooper Vera M Costa Koustuv Dalal Lalit Dandona Rakhi Dandona Farah Daoud Ahmad Daryani Rajat Das Gupta Ian Davis Nicole Davis Weaver Dragos Virgil Davitoiu Jan-Walter De Neve Feleke Mekonnen Demeke Gebre Teklemariam Demoz Kebede Deribe Rupak Desai Aniruddha Deshpande Hanna Demelash Desyibelew Sagnik Dey Samath Dhamminda Dharmaratne Meghnath Dhimal Daniel Diaz Leila Doshmangir Andre R Duraes Laura Dwyer-Lindgren Lucas Earl Roya Ebrahimi Soheil Ebrahimpour Andem Effiong Aziz Eftekhari Elham Ehsani-Chimeh Iman El Sayed Maysaa El Sayed Zaki Maha El Tantawi Ziad El-Khatib Mohammad Hassan Emamian Shymaa Enany Sharareh Eskandarieh Oghenowede Eyawo Maha Ezalarab Mahbobeh Faramarzi Mohammad Fareed Roghiyeh Faridnia Andre Faro Ali Akbar Fazaeli Mehdi Fazlzadeh Netsanet Fentahun Seyed-Mohammad Fereshtehnejad João C Fernandes Irina Filip Florian Fischer Nataliya A Foigt Masoud Foroutan Joel Msafiri Francis Takeshi Fukumoto Nancy Fullman Silvano Gallus Destallem Gebremedhin Gebre Tsegaye Tewelde Gebrehiwot Gebreamlak Gebremedhn Gebremeskel Bradford D Gessner Birhanu Geta Peter W Gething Reza Ghadimi Keyghobad Ghadiri Mahsa Ghajarzadeh Ahmad Ghashghaee Paramjit Singh Gill Tiffany K Gill Nick Golding Nelson G M Gomes Philimon N Gona Sameer Vali Gopalani Giuseppe Gorini Bárbara Niegia Garcia Goulart Nicholas Graetz Felix Greaves Manfred S Green Yuming Guo Arvin Haj-Mirzaian Arya Haj-Mirzaian Brian James Hall Samer Hamidi Hamidreza Haririan Josep Maria Haro Milad Hasankhani Edris Hasanpoor Amir Hasanzadeh Hadi Hassankhani Hamid Yimam Hassen Mohamed I Hegazy Delia Hendrie Fatemeh Heydarpour Thomas R Hird Chi Linh Hoang Gillian Hollerich Enayatollah Homaie Rad Mojtaba Hoseini-Ghahfarokhi Naznin Hossain Mostafa Hosseini Mehdi Hosseinzadeh Mihaela Hostiuc Sorin Hostiuc Mowafa Househ Mohamed Hsairi Olayinka Stephen Ilesanmi Mohammad Hasan Imani-Nasab Usman Iqbal Seyed Sina Naghibi Irvani Nazrul Islam Sheikh Mohammed Shariful Islam Mikk Jürisson Nader Jafari Balalami Amir Jalali Javad Javidnia Achala Upendra Jayatilleke Ensiyeh Jenabi John S Ji Yash B Jobanputra Kimberly Johnson Jost B Jonas Zahra Jorjoran Shushtari Jacek Jerzy Jozwiak Ali Kabir Amaha Kahsay Hamed Kalani Rohollah Kalhor Manoochehr Karami Surendra Karki Amir Kasaeian Nicholas J Kassebaum Peter Njenga 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R Nielsen Dina Nur Anggraini Ningrum Yirga Legesse Nirayo Molly R Nixon Chukwudi A Nnaji Marzieh Nojomi Mehdi Noroozi Shirin Nosratnejad Jean Jacques Noubiap Soraya Nouraei Motlagh Richard Ofori-Asenso Felix Akpojene Ogbo Kelechi E Oladimeji Andrew T Olagunju Meysam Olfatifar Solomon Olum Bolajoko Olubukunola Olusanya Mojisola Morenike Oluwasanu Obinna E Onwujekwe Eyal Oren Doris D V Ortega-Altamirano Alberto Ortiz Osayomwanbo Osarenotor Frank B Osei Aaron E Osgood-Zimmerman Stanislav S Otstavnov Mayowa Ojo Owolabi Mahesh P A Abdol Sattar Pagheh Smita Pakhale Songhomitra Panda-Jonas Animika Pandey Eun-Kee Park Hadi Parsian Tahereh Pashaei Sangram Kishor Patel Veincent Christian Filipino Pepito Alexandre Pereira Samantha Perkins Brandon V Pickering Thomas Pilgrim Majid Pirestani Bakhtiar Piroozi Meghdad Pirsaheb Oleguer Plana-Ripoll Hadi Pourjafar Parul Puri Mostafa Qorbani Hedley Quintana Mohammad Rabiee Navid Rabiee Amir Radfar Alireza Rafiei Fakher Rahim Zohreh Rahimi Vafa Rahimi-Movaghar Shadi Rahimzadeh Fatemeh Rajati Sree Bhushan Raju Azra Ramezankhani Chhabi Lal Ranabhat Davide Rasella Vahid Rashedi Lal Rawal Robert C Reiner Andre M N Renzaho Satar Rezaei Aziz Rezapour Seyed Mohammad Riahi Ana Isabel Ribeiro Leonardo Roever Elias Merdassa Roro Max Roser Gholamreza Roshandel Daem Roshani Ali Rostami Enrico Rubagotti Salvatore Rubino Siamak Sabour Nafis Sadat Ehsan Sadeghi Reza Saeedi Yahya Safari Roya Safari-Faramani Mahdi Safdarian Amirhossein Sahebkar Mohammad Reza Salahshoor Nasir Salam Payman Salamati Farkhonde Salehi Saleh Salehi Zahabi Yahya Salimi Hamideh Salimzadeh Joshua A Salomon Evanson Zondani Sambala Abdallah M Samy Milena M Santric Milicevic Bruno Piassi Sao Jose Sivan Yegnanarayana Iyer Saraswathy Rodrigo Sarmiento-Suárez Benn Sartorius Brijesh Sathian Sonia Saxena Alyssa N Sbarra Lauren E Schaeffer David C Schwebel Sadaf G Sepanlou Seyedmojtaba Seyedmousavi Faramarz Shaahmadi Masood Ali Shaikh Mehran Shams-Beyranvand Amir Shamshirian Morteza Shamsizadeh Kiomars Sharafi Mehdi Sharif Mahdi Sharif-Alhoseini Hamid Sharifi Jayendra Sharma Rajesh Sharma Aziz Sheikh Chloe Shields Mika Shigematsu Rahman Shiri Ivy Shiue Kerem Shuval Tariq J Siddiqi João Pedro Silva Jasvinder A Singh Dhirendra Narain Sinha Malede Mequanent Sisay Solomon Sisay Karen Sliwa David L Smith Ranjani Somayaji Moslem Soofi Joan B Soriano Chandrashekhar T Sreeramareddy Agus Sudaryanto Mu'awiyyah Babale Sufiyan Bryan L Sykes P N Sylaja Rafael Tabarés-Seisdedos Karen M Tabb Takahiro Tabuchi Nuno Taveira Mohamad-Hani Temsah Abdullah Sulieman Terkawi Zemenu Tadesse Tessema Kavumpurathu Raman Thankappan Sathish Thirunavukkarasu Quyen G To Marcos Roberto Tovani-Palone Bach Xuan Tran Khanh Bao Tran Irfan Ullah Muhammad Shariq Usman Olalekan A Uthman Amir Vahedian-Azimi Pascual R Valdez Job F M van Boven Tommi Juhani Vasankari Yasser Vasseghian Yousef Veisani Narayanaswamy Venketasubramanian Francesco S Violante Sergey Konstantinovitch Vladimirov Vasily Vlassov Theo Vos Giang Thu Vu Isidora S Vujcic Yasir Waheed Jon Wakefield Haidong Wang Yafeng Wang Yuan-Pang Wang Joseph L Ward Robert G Weintraub Kidu Gidey Weldegwergs Girmay Teklay Weldesamuel Ronny Westerman Charles Shey Wiysonge Dawit Zewdu Wondafrash Lauren Woyczynski Ai-Min Wu Gelin Xu Abbas Yadegar Tomohide Yamada Vahid Yazdi-Feyzabadi Christopher Sabo Yilgwan Paul Yip Naohiro Yonemoto Javad Yoosefi Lebni Mustafa Z Younis Mahmoud Yousefifard Hebat-Allah Salah A Yousof Chuanhua Yu Hasan Yusefzadeh Erfan Zabeh Telma Zahirian Moghadam Sojib Bin Zaman Mohammad Zamani Hamed Zandian Alireza Zangeneh Taddese Alemu Zerfu Yunquan Zhang Arash Ziapour Sanjay Zodpey Christopher J L Murray Simon I Hay

Nature 2019 10 16;574(7778):353-358. Epub 2019 Oct 16.

Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2-to end preventable child deaths by 2030-we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000-2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations.
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http://dx.doi.org/10.1038/s41586-019-1545-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6800389PMC
October 2019

Identifying residual hotspots and mapping lower respiratory infection morbidity and mortality in African children from 2000 to 2017.

Nat Microbiol 2019 12 30;4(12):2310-2318. Epub 2019 Sep 30.

Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.

Lower respiratory infections (LRIs) are the leading cause of death in children under the age of 5, despite the existence of vaccines against many of their aetiologies. Furthermore, more than half of these deaths occur in Africa. Geospatial models can provide highly detailed estimates of trends subnationally, at the level where implementation of health policies has the greatest impact. We used Bayesian geostatistical modelling to estimate LRI incidence, prevalence and mortality in children under 5 subnationally in Africa for 2000-2017, using surveys covering 1.46 million children and 9,215,000 cases of LRI. Our model reveals large within-country variation in both health burden and its change over time. While reductions in childhood morbidity and mortality due to LRI were estimated for almost every country, we expose a cluster of residual high risk across seven countries, which averages 5.5 LRI deaths per 1,000 children per year. The preventable nature of the vast majority of LRI deaths mandates focused health system efforts in specific locations with the highest burden.
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http://dx.doi.org/10.1038/s41564-019-0562-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6877470PMC
December 2019

Mapping exclusive breastfeeding in Africa between 2000 and 2017.

Nat Med 2019 08 22;25(8):1205-1212. Epub 2019 Jul 22.

Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.

Exclusive breastfeeding (EBF)-giving infants only breast-milk (and medications, oral rehydration salts and vitamins as needed) with no additional food or drink for their first six months of life-is one of the most effective strategies for preventing child mortality. Despite these advantages, only 37% of infants under 6 months of age in Africa were exclusively breastfed in 2017, and the practice of EBF varies by population. Here, we present a fine-scale geospatial analysis of EBF prevalence and trends in 49 African countries from 2000-2017, providing policy-relevant administrative- and national-level estimates. Previous national-level analyses found that most countries will not meet the World Health Organization's Global Nutrition Target of 50% EBF prevalence by 2025. Our analyses show that even fewer will achieve this ambition in all subnational areas. Our estimates provide the ability to visualize subnational EBF variability and identify populations in need of additional breastfeeding support.
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http://dx.doi.org/10.1038/s41591-019-0525-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6749549PMC
August 2019

The current and future global distribution and population at risk of dengue.

Nat Microbiol 2019 09 10;4(9):1508-1515. Epub 2019 Jun 10.

Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.

Dengue is a mosquito-borne viral infection that has spread throughout the tropical world over the past 60 years and now affects over half the world's population. The geographical range of dengue is expected to further expand due to ongoing global phenomena including climate change and urbanization. We applied statistical mapping techniques to the most extensive database of case locations to date to predict global environmental suitability for the virus as of 2015. We then made use of climate, population and socioeconomic projections for the years 2020, 2050 and 2080 to project future changes in virus suitability and human population at risk. This study is the first to consider the spread of Aedes mosquito vectors to project dengue suitability. Our projections provide a key missing piece of evidence for the changing global threat of vector-borne disease and will help decision-makers worldwide to better prepare for and respond to future changes in dengue risk.
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http://dx.doi.org/10.1038/s41564-019-0476-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6784886PMC
September 2019

Mapping HIV prevalence in sub-Saharan Africa between 2000 and 2017.

Nature 2019 06 15;570(7760):189-193. Epub 2019 May 15.

Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.

HIV/AIDS is a leading cause of disease burden in sub-Saharan Africa. Existing evidence has demonstrated that there is substantial local variation in the prevalence of HIV; however, subnational variation has not been investigated at a high spatial resolution across the continent. Here we explore within-country variation at a 5 × 5-km resolution in sub-Saharan Africa by estimating the prevalence of HIV among adults (aged 15-49 years) and the corresponding number of people living with HIV from 2000 to 2017. Our analysis reveals substantial within-country variation in the prevalence of HIV throughout sub-Saharan Africa and local differences in both the direction and rate of change in HIV prevalence between 2000 and 2017, highlighting the degree to which important local differences are masked when examining trends at the country level. These fine-scale estimates of HIV prevalence across space and time provide an important tool for precisely targeting the interventions that are necessary to bringing HIV infections under control in sub-Saharan Africa.
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http://dx.doi.org/10.1038/s41586-019-1200-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6601349PMC
June 2019

Publisher Correction: Past and future spread of the arbovirus vectors Aedes aegypti and Aedes albopictus.

Nat Microbiol 2019 May;4(5):900

School of BioSciences, University of Melbourne, Parkville, Victoria, Australia.

In the version of this Article originally published, the affiliation for author Catherine Linard was incorrectly stated as 'Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK'. The correct affiliation is 'Spatial Epidemiology Lab (SpELL), Universite Libre de Bruxelles, Brussels, Belgium'. The affiliation for author Hongjie Yu was also incorrectly stated as 'Department of Statistics, Harvard University, Cambridge, MA, USA'. The correct affiliation is 'School of Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China'. This has now been amended in all versions of the Article.
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http://dx.doi.org/10.1038/s41564-019-0429-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608402PMC
May 2019

Past and future spread of the arbovirus vectors Aedes aegypti and Aedes albopictus.

Nat Microbiol 2019 05 4;4(5):854-863. Epub 2019 Mar 4.

School of BioSciences, University of Melbourne, Parkville, Victoria, Australia.

The global population at risk from mosquito-borne diseases-including dengue, yellow fever, chikungunya and Zika-is expanding in concert with changes in the distribution of two key vectors: Aedes aegypti and Aedes albopictus. The distribution of these species is largely driven by both human movement and the presence of suitable climate. Using statistical mapping techniques, we show that human movement patterns explain the spread of both species in Europe and the United States following their introduction. We find that the spread of Ae. aegypti is characterized by long distance importations, while Ae. albopictus has expanded more along the fringes of its distribution. We describe these processes and predict the future distributions of both species in response to accelerating urbanization, connectivity and climate change. Global surveillance and control efforts that aim to mitigate the spread of chikungunya, dengue, yellow fever and Zika viruses must consider the so far unabated spread of these mosquitos. Our maps and predictions offer an opportunity to strategically target surveillance and control programmes and thereby augment efforts to reduce arbovirus burden in human populations globally.
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http://dx.doi.org/10.1038/s41564-019-0376-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6522366PMC
May 2019

Global Mortality From Firearms, 1990-2016.

Authors:
Mohsen Naghavi Laurie B Marczak Michael Kutz Katya Anne Shackelford Megha Arora Molly Miller-Petrie Miloud Taki Eddine Aichour Nadia Akseer Rajaa M Al-Raddadi Khurshid Alam Suliman A Alghnam Carl Abelardo T Antonio Olatunde Aremu Amit Arora Mohsen Asadi-Lari Reza Assadi Tesfay Mehari Atey Leticia Avila-Burgos Ashish Awasthi Beatriz Paulina Ayala Quintanilla Suzanne Lyn Barker-Collo Till Winfried Bärnighausen Shahrzad Bazargan-Hejazi Masoud Behzadifar Meysam Behzadifar James R Bennett Ashish Bhalla Zulfiqar A Bhutta Arebu Issa Bilal Guilherme Borges Rohan Borschmann Alexandra Brazinova Julio Cesar Campuzano Rincon Félix Carvalho Carlos A Castañeda-Orjuela Lalit Dandona Rakhi Dandona Paul I Dargan Diego De Leo Samath Dhamminda Dharmaratne Eric L Ding Huyen Phuc Do David Teye Doku Kerrie E Doyle Tim Robert Driscoll Dumessa Edessa Ziad El-Khatib Aman Yesuf Endries Alireza Esteghamati Andre Faro Farshad Farzadfar Valery L Feigin Florian Fischer Kyle J Foreman Richard Charles Franklin Nancy Fullman Neal D Futran Tsegaye Tewelde Gebrehiwot Reyna Alma Gutiérrez Nima Hafezi-Nejad Hassan Haghparast Bidgoli Gessessew Bugssa Hailu Josep Maria Haro Hamid Yimam Hassen Caitlin Hawley Delia Hendrie Martha Híjar Guoqing Hu Olayinka Stephen Ilesanmi Mihajlo Jakovljevic Spencer L James Sudha Jayaraman Jost B Jonas Amaha Kahsay Amir Kasaeian Peter Njenga Keiyoro Yousef Khader Ibrahim A Khalil Young-Ho Khang Jagdish Khubchandani Aliasghar Ahmad Kiadaliri Christian Kieling Yun Jin Kim Soewarta Kosen Kristopher J Krohn G Anil Kumar Faris Hasan Lami Van C Lansingh Heidi Jane Larson Shai Linn Raimundas Lunevicius Hassan Magdy Abd El Razek Muhammed Magdy Abd El Razek Reza Malekzadeh Deborah Carvalho Malta Amanda J Mason-Jones Richard Matzopoulos Peter T N Memiah Walter Mendoza Tuomo J Meretoja Haftay Berhane Mezgebe Ted R Miller Shafiu Mohammed Maziar Moradi-Lakeh Rintaro Mori Devina Nand Cuong Tat Nguyen Quyen Le Nguyen Dina Nur Anggraini Ningrum Felix Akpojene Ogbo Andrew T Olagunju George C Patton Michael R Phillips Suzanne Polinder Farshad Pourmalek Mostafa Qorbani Afarin Rahimi-Movaghar Vafa Rahimi-Movaghar Mahfuzar Rahman Rajesh Kumar Rai Chhabi Lal Ranabhat David Laith Rawaf Salman Rawaf Ali Rowhani-Rahbar Mahdi Safdarian Saeid Safiri Rajesh Sagar Joseph S Salama Juan Sanabria Milena M Santric Milicevic Rodrigo Sarmiento-Suárez Benn Sartorius Maheswar Satpathy David C Schwebel Soraya Seedat Sadaf G Sepanlou Masood Ali Shaikh Nigussie Tadesse Sharew Ivy Shiue Jasvinder A Singh Mekonnen Sisay Vegard Skirbekk Adauto Martins Soares Filho Dan J Stein Mark Andrew Stokes Mu'awiyyah Babale Sufiyan Mamta Swaroop Bryan L Sykes Rafael Tabarés-Seisdedos Fentaw Tadese Bach Xuan Tran Tung Thanh Tran Kingsley Nnanna Ukwaja Tommi Juhani Vasankari Vasily Vlassov Andrea Werdecker Pengpeng Ye Paul Yip Naohiro Yonemoto Mustafa Z Younis Zoubida Zaidi Maysaa El Sayed Zaki Simon I Hay Stephen S Lim Alan D Lopez Ali H Mokdad Theo Vos Christopher J L Murray

JAMA 2018 08;320(8):792-814

Institute for Health Metrics and Evaluation, University of Washington, Seattle.

Importance: Understanding global variation in firearm mortality rates could guide prevention policies and interventions.

Objective: To estimate mortality due to firearm injury deaths from 1990 to 2016 in 195 countries and territories.

Design, Setting, And Participants: This study used deidentified aggregated data including 13 812 location-years of vital registration data to generate estimates of levels and rates of death by age-sex-year-location. The proportion of suicides in which a firearm was the lethal means was combined with an estimate of per capita gun ownership in a revised proxy measure used to evaluate the relationship between availability or access to firearms and firearm injury deaths.

Exposures: Firearm ownership and access.

Main Outcomes And Measures: Cause-specific deaths by age, sex, location, and year.

Results: Worldwide, it was estimated that 251 000 (95% uncertainty interval [UI], 195 000-276 000) people died from firearm injuries in 2016, with 6 countries (Brazil, United States, Mexico, Colombia, Venezuela, and Guatemala) accounting for 50.5% (95% UI, 42.2%-54.8%) of those deaths. In 1990, there were an estimated 209 000 (95% UI, 172 000 to 235 000) deaths from firearm injuries. Globally, the majority of firearm injury deaths in 2016 were homicides (64.0% [95% UI, 54.2%-68.0%]; absolute value, 161 000 deaths [95% UI, 107 000-182 000]); additionally, 27% were firearm suicide deaths (67 500 [95% UI, 55 400-84 100]) and 9% were unintentional firearm deaths (23 000 [95% UI, 18 200-24 800]). From 1990 to 2016, there was no significant decrease in the estimated global age-standardized firearm homicide rate (-0.2% [95% UI, -0.8% to 0.2%]). Firearm suicide rates decreased globally at an annualized rate of 1.6% (95% UI, 1.1-2.0), but in 124 of 195 countries and territories included in this study, these levels were either constant or significant increases were estimated. There was an annualized decrease of 0.9% (95% UI, 0.5%-1.3%) in the global rate of age-standardized firearm deaths from 1990 to 2016. Aggregate firearm injury deaths in 2016 were highest among persons aged 20 to 24 years (for men, an estimated 34 700 deaths [95% UI, 24 900-39 700] and for women, an estimated 3580 deaths [95% UI, 2810-4210]). Estimates of the number of firearms by country were associated with higher rates of firearm suicide (P < .001; R2 = 0.21) and homicide (P < .001; R2 = 0.35).

Conclusions And Relevance: This study estimated between 195 000 and 276 000 firearm injury deaths globally in 2016, the majority of which were firearm homicides. Despite an overall decrease in rates of firearm injury death since 1990, there was variation among countries and across demographic subgroups.
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http://dx.doi.org/10.1001/jama.2018.10060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6143020PMC
August 2018

Health Effects of Overweight and Obesity in 195 Countries over 25 Years.

Authors:
Ashkan Afshin Mohammad H Forouzanfar Marissa B Reitsma Patrick Sur Kara Estep Alex Lee Laurie Marczak Ali H Mokdad Maziar Moradi-Lakeh Mohsen Naghavi Joseph S Salama Theo Vos Kalkidan H Abate Cristiana Abbafati Muktar B Ahmed Ziyad Al-Aly Ala’a Alkerwi Rajaa Al-Raddadi Azmeraw T Amare Alemayehu Amberbir Adeladza K Amegah Erfan Amini Stephen M Amrock Ranjit M Anjana Johan Ärnlöv Hamid Asayesh Amitava Banerjee Aleksandra Barac Estifanos Baye Derrick A Bennett Addisu S Beyene Sibhatu Biadgilign Stan Biryukov Espen Bjertness Dube J Boneya Ismael Campos-Nonato Juan J Carrero Pedro Cecilio Kelly Cercy Liliana G Ciobanu Leslie Cornaby Solomon A Damtew Lalit Dandona Rakhi Dandona Samath D Dharmaratne Bruce B Duncan Babak Eshrati Alireza Esteghamati Valery L Feigin João C Fernandes Thomas Fürst Tsegaye T Gebrehiwot Audra Gold Philimon N Gona Atsushi Goto Tesfa D Habtewold Kokeb T Hadush Nima Hafezi-Nejad Simon I Hay Masako Horino Farhad Islami Ritul Kamal Amir Kasaeian Srinivasa V Katikireddi Andre P Kengne Chandrasekharan N Kesavachandran Yousef S Khader Young-Ho Khang Jagdish Khubchandani Daniel Kim Yun J Kim Yohannes Kinfu Soewarta Kosen Tiffany Ku Barthelemy Kuate Defo G Anil Kumar Heidi J Larson Mall Leinsalu Xiaofeng Liang Stephen S Lim Patrick Liu Alan D Lopez Rafael Lozano Azeem Majeed Reza Malekzadeh Deborah C Malta Mohsen Mazidi Colm McAlinden Stephen T McGarvey Desalegn T Mengistu George A Mensah Gert B M Mensink Haftay B Mezgebe Erkin M Mirrakhimov Ulrich O Mueller Jean J Noubiap Carla M Obermeyer Felix A Ogbo Mayowa O Owolabi George C Patton Farshad Pourmalek Mostafa Qorbani Anwar Rafay Rajesh K Rai Chhabi L Ranabhat Nikolas Reinig Saeid Safiri Joshua A Salomon Juan R Sanabria Itamar S Santos Benn Sartorius Monika Sawhney Josef Schmidhuber Aletta E Schutte Maria I Schmidt Sadaf G Sepanlou Moretza Shamsizadeh Sara Sheikhbahaei Min-Jeong Shin Rahman Shiri Ivy Shiue Hirbo S Roba Diego A S Silva Jonathan I Silverberg Jasvinder A Singh Saverio Stranges Soumya Swaminathan Rafael Tabarés-Seisdedos Fentaw Tadese Bemnet A Tedla Balewgizie S Tegegne Abdullah S Terkawi J S Thakur Marcello Tonelli Roman Topor-Madry Stefanos Tyrovolas Kingsley N Ukwaja Olalekan A Uthman Masoud Vaezghasemi Tommi Vasankari Vasiliy V Vlassov Stein E Vollset Elisabete Weiderpass Andrea Werdecker Joshua Wesana Ronny Westerman Yuichiro Yano Naohiro Yonemoto Gerald Yonga Zoubida Zaidi Zerihun M Zenebe Ben Zipkin Christopher J L Murray

N Engl J Med 2017 07 12;377(1):13-27. Epub 2017 Jun 12.

Background: Although the rising pandemic of obesity has received major attention in many countries, the effects of this attention on trends and the disease burden of obesity remain uncertain.

Methods: We analyzed data from 68.5 million persons to assess the trends in the prevalence of overweight and obesity among children and adults between 1980 and 2015. Using the Global Burden of Disease study data and methods, we also quantified the burden of disease related to high body-mass index (BMI), according to age, sex, cause, and BMI in 195 countries between 1990 and 2015.

Results: In 2015, a total of 107.7 million children and 603.7 million adults were obese. Since 1980, the prevalence of obesity has doubled in more than 70 countries and has continuously increased in most other countries. Although the prevalence of obesity among children has been lower than that among adults, the rate of increase in childhood obesity in many countries has been greater than the rate of increase in adult obesity. High BMI accounted for 4.0 million deaths globally, nearly 40% of which occurred in persons who were not obese. More than two thirds of deaths related to high BMI were due to cardiovascular disease. The disease burden related to high BMI has increased since 1990; however, the rate of this increase has been attenuated owing to decreases in underlying rates of death from cardiovascular disease.

Conclusions: The rapid increase in the prevalence and disease burden of elevated BMI highlights the need for continued focus on surveillance of BMI and identification, implementation, and evaluation of evidence-based interventions to address this problem. (Funded by the Bill and Melinda Gates Foundation.).
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http://dx.doi.org/10.1056/NEJMoa1614362DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5477817PMC
July 2017

Global Burden of Hypertension and Systolic Blood Pressure of at Least 110 to 115 mm Hg, 1990-2015.

JAMA 2017 01;317(2):165-182

Institute for Health Metrics and Evaluation, University of Washington, Seattle.

Importance: Elevated systolic blood (SBP) pressure is a leading global health risk. Quantifying the levels of SBP is important to guide prevention policies and interventions.

Objective: To estimate the association between SBP of at least 110 to 115 mm Hg and SBP of 140 mm Hg or higher and the burden of different causes of death and disability by age and sex for 195 countries and territories, 1990-2015.

Design: A comparative risk assessment of health loss related to SBP. Estimated distribution of SBP was based on 844 studies from 154 countries (published 1980-2015) of 8.69 million participants. Spatiotemporal Gaussian process regression was used to generate estimates of mean SBP and adjusted variance for each age, sex, country, and year. Diseases with sufficient evidence for a causal relationship with high SBP (eg, ischemic heart disease, ischemic stroke, and hemorrhagic stroke) were included in the primary analysis.

Main Outcomes And Measures: Mean SBP level, cause-specific deaths, and health burden related to SBP (≥110-115 mm Hg and also ≥140 mm Hg) by age, sex, country, and year.

Results: Between 1990-2015, the rate of SBP of at least 110 to 115 mm Hg increased from 73 119 (95% uncertainty interval [UI], 67 949-78 241) to 81 373 (95% UI, 76 814-85 770) per 100 000, and SBP of 140 mm Hg or higher increased from 17 307 (95% UI, 17 117-17 492) to 20 526 (95% UI, 20 283-20 746) per 100 000. The estimated annual death rate per 100 000 associated with SBP of at least 110 to 115 mm Hg increased from 135.6 (95% UI, 122.4-148.1) to 145.2 (95% UI 130.3-159.9) and the rate for SBP of 140 mm Hg or higher increased from 97.9 (95% UI, 87.5-108.1) to 106.3 (95% UI, 94.6-118.1). For loss of DALYs associated with systolic blood pressure of 140 mm Hg or higher, the loss increased from 95.9 million (95% uncertainty interval [UI], 87.0-104.9 million) to 143.0 million (95% UI, 130.2-157.0 million) [corrected], and for SBP of 140 mm Hg or higher, the loss increased from 5.2 million (95% UI, 4.6-5.7 million) to 7.8 million (95% UI, 7.0-8.7 million). The largest numbers of SBP-related deaths were caused by ischemic heart disease (4.9 million [95% UI, 4.0-5.7 million]; 54.5%), hemorrhagic stroke (2.0 million [95% UI, 1.6-2.3 million]; 58.3%), and ischemic stroke (1.5 million [95% UI, 1.2-1.8 million]; 50.0%). In 2015, China, India, Russia, Indonesia, and the United States accounted for more than half of the global DALYs related to SBP of at least 110 to 115 mm Hg.

Conclusions And Relevance: In international surveys, although there is uncertainty in some estimates, the rate of elevated SBP (≥110-115 and ≥140 mm Hg) increased substantially between 1990 and 2015, and DALYs and deaths associated with elevated SBP also increased. Projections based on this sample suggest that in 2015, an estimated 3.5 billion adults had SBP of at least 110 to 115 mm Hg and 874 million adults had SBP of 140 mm Hg or higher.
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http://dx.doi.org/10.1001/jama.2016.19043DOI Listing
January 2017

Global, Regional, and National Cancer Incidence, Mortality, Years of Life Lost, Years Lived With Disability, and Disability-Adjusted Life-years for 32 Cancer Groups, 1990 to 2015: A Systematic Analysis for the Global Burden of Disease Study.

Authors:
Christina Fitzmaurice Christine Allen Ryan M Barber Lars Barregard Zulfiqar A Bhutta Hermann Brenner Daniel J Dicker Odgerel Chimed-Orchir Rakhi Dandona Lalit Dandona Tom Fleming Mohammad H Forouzanfar Jamie Hancock Roderick J Hay Rachel Hunter-Merrill Chantal Huynh H Dean Hosgood Catherine O Johnson Jost B Jonas Jagdish Khubchandani G Anil Kumar Michael Kutz Qing Lan Heidi J Larson Xiaofeng Liang Stephen S Lim Alan D Lopez Michael F MacIntyre Laurie Marczak Neal Marquez Ali H Mokdad Christine Pinho Farshad Pourmalek Joshua A Salomon Juan Ramon Sanabria Logan Sandar Benn Sartorius Stephen M Schwartz Katya A Shackelford Kenji Shibuya Jeff Stanaway Caitlyn Steiner Jiandong Sun Ken Takahashi Stein Emil Vollset Theo Vos Joseph A Wagner Haidong Wang Ronny Westerman Hajo Zeeb Leo Zoeckler Foad Abd-Allah Muktar Beshir Ahmed Samer Alabed Noore K Alam Saleh Fahed Aldhahri Girma Alem Mulubirhan Assefa Alemayohu Raghib Ali Rajaa Al-Raddadi Azmeraw Amare Yaw Amoako Al Artaman Hamid Asayesh Niguse Atnafu Ashish Awasthi Huda Ba Saleem Aleksandra Barac Neeraj Bedi Isabela Bensenor Adugnaw Berhane Eduardo Bernabé Balem Betsu Agnes Binagwaho Dube Boneya Ismael Campos-Nonato Carlos Castañeda-Orjuela Ferrán Catalá-López Peggy Chiang Chioma Chibueze Abdulaal Chitheer Jee-Young Choi Benjamin Cowie Solomon Damtew José das Neves Suhojit Dey Samath Dharmaratne Preet Dhillon Eric Ding Tim Driscoll Donatus Ekwueme Aman Yesuf Endries Maryam Farvid Farshad Farzadfar Joao Fernandes Florian Fischer Tsegaye Tewelde G/Hiwot Alemseged Gebru Sameer Gopalani Alemayehu Hailu Masako Horino Nobuyuki Horita Abdullatif Husseini Inge Huybrechts Manami Inoue Farhad Islami Mihajlo Jakovljevic Spencer James Mehdi Javanbakht Sun Ha Jee Amir Kasaeian Muktar Sano Kedir Yousef S Khader Young-Ho Khang Daniel Kim James Leigh Shai Linn Raimundas Lunevicius Hassan Magdy Abd El Razek Reza Malekzadeh Deborah Carvalho Malta Wagner Marcenes Desalegn Markos Yohannes A Melaku Kidanu G Meles Walter Mendoza Desalegn Tadese Mengiste Tuomo J Meretoja Ted R Miller Karzan Abdulmuhsin Mohammad Alireza Mohammadi Shafiu Mohammed Maziar Moradi-Lakeh Gabriele Nagel Devina Nand Quyen Le Nguyen Sandra Nolte Felix A Ogbo Kelechi E Oladimeji Eyal Oren Mahesh Pa Eun-Kee Park David M Pereira Dietrich Plass Mostafa Qorbani Amir Radfar Anwar Rafay Mahfuzar Rahman Saleem M Rana Kjetil Søreide Maheswar Satpathy Monika Sawhney Sadaf G Sepanlou Masood Ali Shaikh Jun She Ivy Shiue Hirbo Roba Shore Mark G Shrime Samuel So Samir Soneji Vasiliki Stathopoulou Konstantinos Stroumpoulis Muawiyyah Babale Sufiyan Bryan L Sykes Rafael Tabarés-Seisdedos Fentaw Tadese Bemnet Amare Tedla Gizachew Assefa Tessema J S Thakur Bach Xuan Tran Kingsley Nnanna Ukwaja Benjamin S Chudi Uzochukwu Vasiliy Victorovich Vlassov Elisabete Weiderpass Mamo Wubshet Terefe Henock Gebremedhin Yebyo Hassen Hamid Yimam Naohiro Yonemoto Mustafa Z Younis Chuanhua Yu Zoubida Zaidi Maysaa El Sayed Zaki Zerihun Menlkalew Zenebe Christopher J L Murray Mohsen Naghavi

JAMA Oncol 2017 Apr;3(4):524-548

Institute for Health Metrics and Evaluation, University of Washington, Seattle.

Importance: Cancer is the second leading cause of death worldwide. Current estimates on the burden of cancer are needed for cancer control planning.

Objective: To estimate mortality, incidence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs) for 32 cancers in 195 countries and territories from 1990 to 2015.

Evidence Review: Cancer mortality was estimated using vital registration system data, cancer registry incidence data (transformed to mortality estimates using separately estimated mortality to incidence [MI] ratios), and verbal autopsy data. Cancer incidence was calculated by dividing mortality estimates through the modeled MI ratios. To calculate cancer prevalence, MI ratios were used to model survival. To calculate YLDs, prevalence estimates were multiplied by disability weights. The YLLs were estimated by multiplying age-specific cancer deaths by the reference life expectancy. DALYs were estimated as the sum of YLDs and YLLs. A sociodemographic index (SDI) was created for each location based on income per capita, educational attainment, and fertility. Countries were categorized by SDI quintiles to summarize results.

Findings: In 2015, there were 17.5 million cancer cases worldwide and 8.7 million deaths. Between 2005 and 2015, cancer cases increased by 33%, with population aging contributing 16%, population growth 13%, and changes in age-specific rates contributing 4%. For men, the most common cancer globally was prostate cancer (1.6 million cases). Tracheal, bronchus, and lung cancer was the leading cause of cancer deaths and DALYs in men (1.2 million deaths and 25.9 million DALYs). For women, the most common cancer was breast cancer (2.4 million cases). Breast cancer was also the leading cause of cancer deaths and DALYs for women (523 000 deaths and 15.1 million DALYs). Overall, cancer caused 208.3 million DALYs worldwide in 2015 for both sexes combined. Between 2005 and 2015, age-standardized incidence rates for all cancers combined increased in 174 of 195 countries or territories. Age-standardized death rates (ASDRs) for all cancers combined decreased within that timeframe in 140 of 195 countries or territories. Countries with an increase in the ASDR due to all cancers were largely located on the African continent. Of all cancers, deaths between 2005 and 2015 decreased significantly for Hodgkin lymphoma (-6.1% [95% uncertainty interval (UI), -10.6% to -1.3%]). The number of deaths also decreased for esophageal cancer, stomach cancer, and chronic myeloid leukemia, although these results were not statistically significant.

Conclusion And Relevance: As part of the epidemiological transition, cancer incidence is expected to increase in the future, further straining limited health care resources. Appropriate allocation of resources for cancer prevention, early diagnosis, and curative and palliative care requires detailed knowledge of the local burden of cancer. The GBD 2015 study results demonstrate that progress is possible in the war against cancer. However, the major findings also highlight an unmet need for cancer prevention efforts, including tobacco control, vaccination, and the promotion of physical activity and a healthy diet.
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http://dx.doi.org/10.1001/jamaoncol.2016.5688DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6103527PMC
April 2017

Geographic variation in plant community structure of salt marshes: species, functional and phylogenetic perspectives.

PLoS One 2015 26;10(5):e0127781. Epub 2015 May 26.

Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America.

In general, community similarity is thought to decay with distance; however, this view may be complicated by the relative roles of different ecological processes at different geographical scales, and by the compositional perspective (e.g. species, functional group and phylogenetic lineage) used. Coastal salt marshes are widely distributed worldwide, but no studies have explicitly examined variation in salt marsh plant community composition across geographical scales, and from species, functional and phylogenetic perspectives. Based on studies in other ecosystems, we hypothesized that, in coastal salt marshes, community turnover would be more rapid at local versus larger geographical scales; and that community turnover patterns would diverge among compositional perspectives, with a greater distance decay at the species level than at the functional or phylogenetic levels. We tested these hypotheses in salt marshes of two regions: The southern Atlantic and Gulf Coasts of the United States. We examined the characteristics of plant community composition at each salt marsh site, how community similarity decayed with distance within individual salt marshes versus among sites in each region, and how community similarity differed among regions, using species, functional and phylogenetic perspectives. We found that results from the three compositional perspectives generally showed similar patterns: there was strong variation in community composition within individual salt marsh sites across elevation; in contrast, community similarity decayed with distance four to five orders of magnitude more slowly across sites within each region. Overall, community dissimilarity of salt marshes was lowest on the southern Atlantic Coast, intermediate on the Gulf Coast, and highest between the two regions. Our results indicated that local gradients are relatively more important than regional processes in structuring coastal salt marsh communities. Our results also suggested that in ecosystems with low species diversity, functional and phylogenetic approaches may not provide additional insight over a species-based approach.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0127781PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4444317PMC
April 2016

Riparian forest composition affects stream litter decomposition despite similar microbial and invertebrate communities.

Ecology 2011 Jan;92(1):151-9

Department of Forest Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.

Cross-boundary flows of energy and nutrients link biodiversity and functioning in adjacent ecosystems. The composition of forest tree species can affect the structure and functioning of stream ecosystems due to physical and chemical attributes, as well as changes in terrestrial resource subsidies. We examined how variation in riparian canopy composition (coniferous, deciduous, mixed) affects adjacent trophic levels (invertebrate and microbial consumers) and decomposition of organic matter in small, coastal rainforest streams in southwestern British Columbia. Breakdown rates of higher-quality red alder (Alnus rubra) litter were faster in streams with a greater percentage of deciduous than coniferous riparian canopy, whereas breakdown rates of lower-quality western hemlock (Tsuga heterophylla) litter were independent of riparian forest composition. When invertebrates were excluded using fine mesh, breakdown rates of both litter species were an order of magnitude less and were not significantly affected by riparian forest composition. Stream invertebrate and microbial communities were similar among riparian forest composition, with most variation attributed to leaf litter species. Invertebrate taxa richness and shredder biomass were higher in A. rubra litter; however, taxa evenness was greatest for T. heterophylla litter and both litter species in coniferous streams. Microbial community diversity (determined from terminal restriction fragment length polymorphisms) was unaffected by riparian forest or litter species. Fungal allele richness was higher than bacterial allele richness, and microbial communities associated with lower-quality T. heterophylla litter had higher diversity (allele uniqueness and richness) than those associated with higher-quality A. rubra litter. Percent variation in breakdown rates was mostly attributed to riparian forest composition in the presence of invertebrates and microbes; however, stream consumer biodiversity at adjacent trophic levels did not explain these patterns. Riparian and stream ecosystems and their biotic communities are linked through exchange and decomposition of detrital resources, and we provide evidence that riparian forest composition affects stream ecosystem catabolism despite similarities in microbial and invertebrate communities.
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http://dx.doi.org/10.1890/10-0028.1DOI Listing
January 2011

Are forested buffers an effective conservation strategy for riparian fauna? An assessment using meta-analysis.

Ecol Appl 2010 Jan;20(1):126-34

University of British Columbia, Department of Forest Sciences, 3041-2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada.

Historically, forested riparian buffers have been created to provide protection for aquatic organisms and aquatic ecosystem functions. Increasingly, new and existing riparian buffers are being used also to meet terrestrial conservation requirements. To test the effectiveness of riparian buffers for conserving terrestrial fauna, we conducted a meta-analysis using published data from 397 comparisons of species abundance in riparian buffers and unharvested (reference) riparian sites. The response of terrestrial species to riparian buffers was not consistent between taxonomic groups; bird and arthropod abundances were significantly greater in buffers relative to unharvested areas, whereas amphibian abundance decreased. Edge-preferring species were more abundant in buffer sites than reference sites, whereas species associated with interior habitat were not significantly different in abundance. The degree of buffer effect on animal abundance was unrelated to buffer width; wider buffers did not result in greater similarity between reference and buffer sites. However, responses to buffer treatment were more variable in buffers <50 m wide, a commonly prescribed width in many management plans. Our results indicate that current buffer prescriptions do not maintain most terrestrial organisms in buffer strips at levels comparable to undisturbed sites.
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http://dx.doi.org/10.1890/08-2064.1DOI Listing
January 2010

The mutualism-parasitism continuum in ectomycorrhizas: a quantitative assessment using meta-analysis.

Ecology 2008 Apr;89(4):1032-42

Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada.

Context dependency is deemed to position the outcomes of species interactions along a continuum of mutualism to parasitism. Thus, it is imperative to understand which factors determine where a particular interspecific interaction falls along the continuum. Over the past 20 years research on the ectomycorrhizal symbiosis has resulted in sufficient independent studies to now generalize about the factors and mechanisms that affect host response to ectomycorrhizas. Using meta-analysis we quantitatively evaluated the role of biotic (partner identity and colonization levels of ectomycorrhizal fungi) and abiotic (phosphorus levels) factors in determining host biomass, height, and shoot:root responses to ectomycorrhizal associations. On average, seedlings across multiple host genera increased in total biomass when inoculated with ectomycorrhizal fungi regardless of the identity of the fungal associate; host genera differed in the magnitude of response for both total biomass and shoot:root ratio. Association with different fungal genera modified only host allocation of biomass to shoots and roots. Neither level of colonization on inoculated seedlings nor the level of contamination on control seedlings relative to colonization levels by target fungi on inoculated seedlings was important in explaining variation in effect sizes for any growth response. None of our proposed factors (identity of partners, colonization level, magnitude of contamination, or duration of association) explained variation in effect sizes for shoot height, although in general seedlings were taller when inoculated with ectomycorrhizal fungi. Phosphorus additions did not influence effect sizes. Although the general trend across studies was for a positive response of hosts to ectomycorrhizal inoculation, publication bias and methodological issues effectively reduce and distort the spectrum on which we evaluate host responses to ectomycorrhizal inoculation. Our results indicate that the variation in ectomycorrhizal fungi perceived by the host may be of a discrete (presence/absence of ectomycorrhizal fungi) rather than continuous nature (variation in identity or abundance of ectomycorrhizal fungi).
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http://dx.doi.org/10.1890/07-0823.1DOI Listing
April 2008

Growth and development rates in a riparian spider are altered by asynchrony between the timing and amount of a resource subsidy.

Oecologia 2008 May;156(2):249-58

Department of Forest Sciences, University of British Columbia, 3041-2424 Main Mall, Vancouver, BC V6T 1Z4, Canada.

Rapid growth in response to increased prey abundance may be induced by environmental variability associated with resource subsidies. Spiders living in riparian areas are subject to frequent, episodic bursts of aquatic prey (subsidies). These periods of high resource abundance may occur at different points in recipient consumers' development through variation in emergence patterns of prey between years or across a landscape. We examine how variable timing of subsidy abundance intersects with life history scheduling to produce different growth and development outcomes for individuals within a population. Through a series of controlled feeding experiments, we tested the hypotheses that the spider Tetragnatha versicolor: (1) exhibits compensatory growth in response to subsidy variability, (2) that rapid increases in mass may result in a greater risk of mortality, and (3) that the timing of subsidy resources relative to the development schedule of this spider may produce different outcomes for individual growth patterns and adult condition. Spiders fed at very high rates grew fastest but also showed evidence of increased mortality risk during moulting. T. versicolor is capable of exhibiting strong growth compensation-individuals suffering initial growth restriction were able to catch up completely with animals on a constant diet utilising the same amount of food. Spiders that received an early pulse of resources (simulating an early arrival of an aquatic insect subsidy to riparian forests) did worse on all measures of development and fitness than spiders that received either a constant supply of food or a late pulse of resources. Importantly, receiving large amounts of food early in life appears to actually confer relative disadvantages in terms of later performance compared with receiving subsidies later in development. Subsidies may provide greater benefits to individuals or age cohorts encountering this resource abundance closer to the onset of reproductive efforts than subsidies arriving early in development.
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http://dx.doi.org/10.1007/s00442-008-0989-yDOI Listing
May 2008

Spiders and subsidies: results from the riparian zone of a coastal temperate rainforest.

J Anim Ecol 2007 Jul;76(4):687-94

Department of Forest Sciences, University of British Columbia, 3041-2424 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z4.

1. Aquatic insects emerging from streams can provide an important energy subsidy to recipient consumers such as riparian web-building spiders. This subsidy has been hypothesized to be of little importance where the primary productivity of the recipient habitat exceeds that of the donor habitat. 2. To test this hypothesis, we manipulated emerging stream insect abundance in a productive riparian rainforest in a replicated design using greenhouse-type exclosures, contrasted with unmanipulated stream reaches (four exclosures on two streams). 3. Experimental exclosures resulted in a 62.9% decrease in aquatic insect abundance in exclusion reaches compared with control reaches. The overall density of riparian spiders was significantly positively correlated with aquatic insect abundances. Horizontal orb weavers (Tetragnathidae) showed a strong response to aquatic insect reduction - abundance at exclosure sites was 57% lower than at control sites. Several spider families that have not been associated with tracking aquatic insect subsidies also showed significantly decreased abundance when aquatic insects were reduced. 4. This result is contrary to predictions of weak subsidy effects where recipient net primary productivity is high. These results suggest that predicting the importance of resource subsidies for food webs requires a focus on the relative abundance of subsidy materials in recipient and donor habitats and not simply on the total flux of energy between systems.
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http://dx.doi.org/10.1111/j.1365-2656.2007.01240.xDOI Listing
July 2007

Meta-analysis: trophic level, habitat, and productivity shape the food web effects of resource subsidies.

Ecology 2007 Jan;88(1):140-8

University of British Columbia, Department of Forest Sciences, 3041-2424 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada.

Studies of the effects of cross-habitat resource subsidies have been a feature of food web ecology over the past decade. To date, most studies have focused on demonstrating the magnitude of a subsidy or documenting its effect in the recipient habitat. Ecologists have yet to develop a satisfactory framework for predicting the magnitude of these effects. We used 115 data sets from 32 studies to compare consumer responses to resource subsidies across recipient habitat type, trophic level, and functional group. Changes in consumer density or biomass in response to subsidies were inconsistent across habitats, trophic, and functional groups. Responses in stream cobble bar and coastline habitats were larger than in other habitats. Contrary to expectation, the magnitude of consumer response was not affected by recipient habitat productivity or the ratio of productivity between donor and recipient habitats. However, consumer response was significantly related to the ratio of subsidy resources to equivalent resources in the recipient habitat. Broad contrasts in productivity are modified by subsidy type, vector, and the physical and biotic characteristics of both donor and recipient habitats. For this reason, the ratio of subsidy to equivalent resources is a more useful tool for predicting the possible effect of a subsidy than coarser contrasts of in situ productivity. The commonness of subsidy effects suggests that many ecosystems need to be studied as open systems.
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http://dx.doi.org/10.1890/0012-9658(2007)88[140:mtlhap]2.0.co;2DOI Listing
January 2007