Genetic risk for earlier menarche also influences peripubertal body mass index. Issue 1 (20th December 2012)

• Record Type: Journal Article
• Authors: Johnson, William; Choh, Audrey C.; Curran, Joanne E.; Czerwinski, Stefan A.; Bellis, Claire; Dyer, Thomas D.; Blangero, John; Towne, Bradford; Demerath, Ellen W.
• Is Part Of: American journal of physical anthropology. Volume 150:Issue 1(2013)
• Page Start: 10
• Page End: 20
• Publication Date: 2012-12-20
• Subjects: Physical anthropology -- Periodicals; Anthropology -- Periodicals; Anthropologie physique -- Périodiques; 599.9
• DOI: 10.1002/ajpa.22121
• Languages: English
• ISSNs: 0002-9483

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>It is unclear whether earlier age at menarche is associated with higher body mass index (BMI) because they share a common genetic underpinning. We investigated the impact of single nucleotide polymorphisms (SNPs) influencing menarche timing on peripubertal BMI. For 556 Fels Longitudinal Study children (277 boys/279 girls) born 1928–1992, a genetic risk score (GRS<sub>42</sub>) was computed as the sum of the number of risk alleles in 42 putative menarche SNPs. Serial BMI <italic>Z</italic>‐scores within ±6.99 years from each individual's age at peak height velocity (Age@PHV) were grouped into seven time points (−6 years, −4 years, –2 years, Age@PHV, +2 years, +4years, and +6 years). Heritability of BMI ranged from 0.53 to 0.85 across the time points. The effect of GRS<sub>42</sub> on BMI <italic>Z</italic>‐scores at each time point was modeled using variance components‐based procedures. GRS<sub>42</sub> had a significant (<italic>P</italic> < 0.05) effect at every time point; an increase of one risk allele was associated with an increase of 0.03–0.08 BMI <italic>Z</italic>‐scores. A separate score (GRS<sub>29</sub>) was computed that excluded 13 of the menarche SNPs previously documented to also influence adiposity; significant main effects were observed at Age@PHV+4 and +6 years. This finding supports a causal effect of advanced sexual development on post‐Age@PHV BMI. Significant positive GRS<sub>42</sub> (or GRS<sub>29</sub>)‐by‐birth year interactions indicate that some genetic influences on BMI have amplified over the 20th century. This gene‐by‐environment interaction also suggests that children with a genetic predisposition to earlier sexual development might avoid elevated BMI through alteration of their nutritional environment. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.</p> </abstract>