Genetic and environmental factors affecting birth size variation: a pooled individual-based analysis of secular trends and global geographical differences using 26 twin cohorts.

Int J Epidemiol 2018 08;47(4):1195-1206

Department of Social Research, University of Helsinki, Helsinki, Finland.

Background: The genetic architecture of birth size may differ geographically and over time. We examined differences in the genetic and environmental contributions to birthweight, length and ponderal index (PI) across geographical-cultural regions (Europe, North America and Australia, and East Asia) and across birth cohorts, and how gestational age modifies these effects.

Methods: Data from 26 twin cohorts in 16 countries including 57 613 monozygotic and dizygotic twin pairs were pooled. Genetic and environmental variations of birth size were estimated using genetic structural equation modelling.

Results: The variance of birthweight and length was predominantly explained by shared environmental factors, whereas the variance of PI was explained both by shared and unique environmental factors. Genetic variance contributing to birth size was small. Adjusting for gestational age decreased the proportions of shared environmental variance and increased the propositions of unique environmental variance. Genetic variance was similar in the geographical-cultural regions, but shared environmental variance was smaller in East Asia than in Europe and North America and Australia. The total variance and shared environmental variance of birth length and PI were greater from the birth cohort 1990-99 onwards compared with the birth cohorts from 1970-79 to 1980-89.

Conclusions: The contribution of genetic factors to birth size is smaller than that of shared environmental factors, which is partly explained by gestational age. Shared environmental variances of birth length and PI were greater in the latest birth cohorts and differed also across geographical-cultural regions. Shared environmental factors are important when explaining differences in the variation of birth size globally and over time.

Download full-text PDF

Source
http://dx.doi.org/10.1093/ije/dyy081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124623PMC
August 2018
55 Reads
9.180 Impact Factor

Publication Analysis

Top Keywords

shared environmental
28
birth size
24
environmental factors
20
environmental variance
16
birth cohorts
12
geographical-cultural regions
12
birth
12
genetic environmental
12
gestational age
12
environmental
11
variance
9
twin cohorts
8
explained shared
8
shared
8
factors birth
8
america australia
8
genetic variance
8
east asia
8
birth length
8
unique environmental
8

The Emergence of Digital Opinion Leaders + Blood Cancer DOL Dashboard

This month we’ve pulled together a dashboard of 20 of the most impactful Digital Opinion Leaders (DOLs) related to Blood Cancers. Please take a live look at the DOL Board for this group of experts.

Read Article

Similar Publications