Lactase persistence and milk consumption are associated with body height in Swedish preadolescents and adolescents

Background: Body height is a classic polygenic trait. About 80%-90% of height is inherited and 10%-20% owed to environmental factors, of which the most important ones are nutrition and diseases in preadolescents and adolescents. Objective: The aim of this study was to explore potential relations between the LCT (lactase) C > T-13910 polymorphism, milk consumption, and body height in a sample of Swedish preadolescents and adolescents. Design: In a cross-sectional study, using a random sample of preadolescents and adolescents (n = 597), dietary intakes were determined. Anthropometric measurements including sexual maturity (Tanner stage) and birth weight were assessed. Parental body height and socio-economic status (SES) were obtained by questionnaires. Genotyping for the LCT C > T-13910 polymorphism that renders individuals lactase persistent (LP) or lactase non-persistent (LNP) was performed by DNA sequencing. Stepwise backward multivariate linear regression was used. Results: Milk consumption was significantly and positively associated with body height (beta =0.45; 95% CI: 0.040, 0.87, p =0.032). Adjustments were performed for sex, parental height, birth weight, body mass index (BMI), SES, and Tanner stage. This model explains 90% of the observed variance of body height (adjusted R-2 =0.89). The presence of the -13910 T allele was positively associated with body height (beta = 2.05; 95% CI: 0.18, 3.92, p =0.032). Conclusions: Milk consumption is positively associated with body height in preadolescents and adolescents. We show for the first time that a nutrigenetic variant might be able to explain in part phenotypic variation of body height in preadolescents and adolescents. Due to the small sample size further studies are needed.