Two British women studies replicated the association between the Val66Met polymorphism in the brain-derived neurotrophic factor (BDNF) and BMI

The goal of this study is to investigate the relationship between the Val66Met polymorphism in the brain-derived neurotrophic factor ( BDNF) and body mass index ( BMI) in two sizable and well-characterized populations of British women: the British Women's Heart and Health Study ( BWHHS) ( age 60-79 years) and the mothers from the Avon Longitudinal Study of Parents and Children ( age 16-44 years). We genotyped the Val66Met polymorphism ( rs6265) in these two populations, and conducted a linear regression analysis to test for an association between this polymorphism and BMI. Both study populations indicated an association between BMI and the Val66Met polymorphism, with individuals carrying the Met-Met genotype having a lower mean BMI than those with the Val-Met or Val-Val genotypes ( in the BWHHS): mean BMI difference =-0.911 kg/m(2), 95% confidence interval ( CI): -1.70 to -0.12, P=0.023; in the mothers from the Avon Longitudinal Study of Parents and Children ( ALSPAC): mean BMI difference = -0.57 kg/m(2), 95% CI: -1.08 to -0.054, P=0.03). In a pooled analysis of these two studies, together with one further published study that provided data in a suitable format for inclusion in our meta-analysis, we found a pooled difference of -0.76 ( 95% CI: -1.16, -0.036) for adult women; I-2-test for heterogeneity 51%, P=0.13. Our study indicated an association between BDNF and BMI in two general population studies of women. The exact role of BDNF in weight regulation merits further investigation. European Journal of Human Genetics ( 2009) 17, 1050-1055; doi:10.1038/ejhg.2008.272; published online 11 February 2009