Publications by authors named "Dieke H J Kok"

2 Publications

  • Page 1 of 1

Bone mineral density in developing children with osteogenesis imperfecta: a longitudinal study with 9 years of follow-up.

Acta Orthop 2013 Aug;84(4):431-6

Department of Orthopaedic Surgery, Wilhelmina Children's Hospital, University Medical Center Utrecht, the Netherlands.

Background And Purpose: Osteogenesis imperfecta (OI) is a heritable disorder of connective tissue caused by a defect in collagen type I synthesis. For bone, this includes fragility, low bone mass, and progressive skeletal deformities, which can result in various degrees of short stature. The purpose of this study was to investigate development of bone mineral density in children with OI.

Patients And Methods: Development of lumbar bone mineral density was studied retrospectively in a cohort of 74 children with OI. Mean age was 16.3 years (SD 4.3). In 52 children, repeated measurements were available. Mean age at the start of measurement was 8.8 years (SD 4.1), and mean follow-up was 9 years (SD 2.7). A longitudinal data analysis was performed. In the total cohort (74 children), a cross-sectional analysis was performed with the latest-measured BMD. Age at the latest BMD measurement was almost equal for girls and boys: 17.4 and 17.7 years respectively.

Result: Mean annual increase in BMD in the 52 children was 0.038 g/cm(2)/year (SD 0.024). Annual increase in BMD was statistically significantly higher in girls, in both the unadjusted and adjusted analysis. In cross-sectional analysis, in the whole cohort the latest-measured lumbar BMD was significantly higher in girls, in the children with OI of type I, in walkers, and in those who were older, in both unadjusted and adjusted analysis.

Interpretation: During 9 years of follow-up, there appeared to be an increase in bone mineral density, which was most pronounced in girls. One possible explanation might be a later growth spurt and older age at peak bone mass in boys.
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August 2013

Quality of life in children with osteogenesis imperfecta treated with oral bisphosphonates (Olpadronate): a 2-year randomized placebo-controlled trial.

Eur J Pediatr 2007 Nov 17;166(11):1155-61. Epub 2007 Feb 17.

Department of Orthopaedic Surgery, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.

Unlabelled: In this double-blind randomised placebo-controlled trial it was investigated during a two-year follow-up whether oral bisphosphonates (Olpadronate 10 mg/m2/day) influence quality of life in children with osteogenesis imperfecta (OI). Thirty-four children with OI (classified according to Sillence criteria), aged 3 to 18 years of age, with a restricted level of ambulation were included. Randomisation was performed using a list of computer generated random numbers to allocate patients to receive Olpadronate or placebo. Quality of life was measured using self-perception profile for children (SPPC) and health-utility index (HUI). Differences between baseline measurements and measurements at two years follow-up were analysed within the Olpadronate and placebo group using a student's t-test. Differences in HUI and SPPC regression coefficients were analysed by random-effects repeated measures analysis (SAS, Proc Mixed, version 8.2), adjusted for age, gender and type of OI. Within the Olpadronate group there was a significant decrease in pain utility; however, difference in six months' regression coefficients between the placebo and Olpadronate group were not significant. Within the placebo group there was a significant increase in scholastic competence and behavioural conduct. The item behavioural conduct showed a steeper annual regression coefficient favourable for the placebo group. In the other SPPC items none of the annual regression coefficients showed a significant difference between the Olpadronate and the placebo group.

Conclusion: We found only slight differences in quality of life in favour of the bisphosphonate group. A small but not significant decrease in pain was detected in the bisphosphonate group.
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November 2007