Puberty is a critical period for the genetic expression of binge eating in girls (Klump et al., in press, Ann Rev Clin Psych). Previous twin studies show dramatic increases in genetic influences on binge eating from... [ view full abstract ]
Puberty is a critical period for the genetic expression of binge eating in girls (Klump et al., in press, Ann Rev Clin Psych). Previous twin studies show dramatic increases in genetic influences on binge eating from pre-puberty (~0%) to mid-puberty and beyond (~50%) (Klump et al., in press, Int J Eat Disorders). However, little is known about the factors that drive these changes in genetic effects. Previous pilot studies in twins (Klump et al., 2010, Psych Med:40(10), 1745-1753) have suggested that the pubertal activation of ovarian hormones may contribute to increases in genetic influences, possibly via hormonally induced changes in gene expression. Nonetheless, large-scale twin studies confirming hormone effects on genetic risk are lacking, particularly those examining both estrogen and progesterone in developmentally diverse samples of girls. Thus, the purpose of the present study was to examine the effects of estrogen and progesterone on genetic influences for binge eating in a large sample of same-sex female twins. Participants included 1,000 female twins (ages 8-15 years) from the Michigan State University Twin Registry. Binge eating was assessed with the Minnesota Eating Behaviors Survey (von Ranson et al., 2005, Eat Behav:6(4), 373-392), while pubertal development was assessed with the Pubertal Development Scale (Petersen et al., 1988, J Youth Adol:17(2), 117-133). Afternoon saliva samples were assayed for estradiol and progesterone levels using enzyme immunoassays. Twin moderation models showed significant and substantial differences in genetic influences on binge eating by estradiol and progesterone levels, even after controlling for the effects of age, body mass index, and onset of menses. Overall, findings suggest that the activation of ovarian hormones may drive changes in genetic effects on binge eating during puberty. Additional studies are needed to identify mechanisms of effects, including potential hormone regulation of gene expression in key neural systems.
