The effects of puberty on genetic risk for disordered eating: evidence for a sex difference

Abstract

Background Differences in genetic influences on disordered eating are present across puberty in girls. Heritability is 0% before puberty, but over 50% during and after puberty. Emerging data suggest that these developmental differences may be due to pubertal increases in ovarian hormones. However, a critical piece of evidence is lacking, namely, knowledge of genetic influences on disordered eating across puberty in boys. Boys do not experience increases in ovarian hormones during puberty. Thus, if pubertal increases in genetic effects are present in boys, then factors in addition to ovarian hormones may drive increases in heritability in girls. The current study was the first to examine this possibility in a sample of 1,006 male and female twins from the Michigan State University Twin Registry. Methods Disordered eating was assessed with the Minnesota Eating Behaviors Survey. Pubertal development was assessed with the Pubertal Development Scale. Results No significant differences in genetic influences on disordered eating were observed in males across any developmental stage. Heritability was 51% in boys during pre-puberty, puberty, and young adulthood. By contrast, in girls, genetic factors accounted for 0% of the variance in pre-puberty, but 51% of the variance during puberty and beyond. Sex differences in genetic effects were only significant during pre-puberty, as the best-fitting models constrained heritability to be equal across all males, pubertal females, and young adult females. Conclusions Results highlight sex-specific effects of puberty on genetic risk for disordered eating and provide indirect evidence of a role for ovarian hormones and/or other female-specific factors.

A longitudinal transactional risk model for early eating disorder onset.

“…There are also differences in risk across sex. For example, puberty appears to influence the heritability of disordered eating in girls but not boys (Klump, Culbert, Slane, Burt, Sisk, & Nigg, 2011). Further investigation of similarities and differences in eating disorder risk by sex are clearly warranted.…”

The emergence of sex differences in risk for disordered eating attitudes during puberty: A role for prenatal testosterone exposure.

“…These same effects may underlie sex differences in risk, where in males, elevated prenatal testosterone exposure masculinizes the central nervous system and increases sensitivity to testosterone during puberty (Wade, 1972). Increased responsiveness to testosterone during puberty may further contribute to a “male-like” nervous system that protects against genetic and phenotypic activation of DE attitudes during and after mid-puberty (Klump et al, 2012). …”

Sex differences in the physiology of eating

“…Klump et al (388), as well as others (27,631,715) have also investigated the biological contributions to the sharp increases in the incidences of bulimia nervosa and binge-eating disorder that occur in girls at the onset of puberty (ϳ8 -10 yr of age). In the Klump et al study (388), they found 1) no detectable heritability of disordered eating in prepubertal girls; 2) heritability of ϳ0.5 in girls during and after puberty; and 3) heritability of ϳ0.5 in boys at all times. In another study (393), they detected significant heritability for disordered eating in 10 -15-yr-old girls with higher plasma estradiol levels, but not in girls with lower estradiol levels.…”