Changes in genetic risk for emotional eating across the menstrual cycle: a longitudinal study

Abstract

Background Previous studies show significant within-person changes in binge eating and emotional eating across the menstrual cycle, with substantial increases in both phenotypes during post-ovulation. Increases in both estradiol and progesterone levels appear to account for these changes in phenotypic risk, possibly via increases in genetic effects. However, to date, no study has examined changes in genetic risk for binge phenotypes (or any other phenotype) across the menstrual cycle. The goal of the present study was to examine within-person changes in genetic risk for emotional eating scores across the menstrual cycle. Methods Participants were 230 female twin pairs (460 twins) from the Michigan State University Twin Registry (MSUTR) who completed daily measures of emotional eating for 45 consecutive days. Menstrual cycle phase was coded based on dates of menstrual bleeding and daily ovarian hormone levels. Results Findings revealed important shifts in genetic and environmental influences, where estimates of genetic influences were two times higher in post- as compared to pre-ovulation. Surprisingly, pre-ovulation was marked by a predominance of environmental influences, including shared environmental effects which have not been previously detected for binge eating phenotypes in adulthood. Conclusions Our study was the first to examine within-person shifts in genetic and environmental influences on a behavioral phenotype across the menstrual cycle. Results highlight a potentially critical role for these shifts in risk for emotional eating across the menstrual cycle and underscore the need for additional, large-scale studies to identify the genetic and environmental factors contributing to menstrual cycle effects.

Differential Effects of Estrogen and Progesterone on Genetic and Environmental Risk for Emotional Eating in Women

“…Our findings preliminarily confirm hypotheses put forth in our previous paper (Klump et al, 2015) about the potential effects of ovarian hormones on etiologic risk. That study examined changes in heritability across the menstrual cycle and showed substantial shared environmental (and minimal genetic) influences on emotional eating during pre-ovulation, and significant genetic (and minimal shared environmental) influences in post-ovulation.…”

“…Nonshared environmental effects were found to be important in low and high groups for both hormones, with decreasing effects when moving from low to high hormone groups. These results mimic what we observed in our menstrual cycle study where nonshared environmental factors were present across all phases of the cycle, yet they decreased somewhat when moving from pre- to post-ovulation (Klump et al, 2015). …”

“…That study examined changes in heritability across the menstrual cycle and showed substantial shared environmental (and minimal genetic) influences on emotional eating during pre-ovulation, and significant genetic (and minimal shared environmental) influences in post-ovulation. We had proposed that estrogen likely contributed to the pre-ovulatory, shared environmental effects (Klump et al, 2015), given the predominance of estrogen during the first half of the menstrual cycle. Although the current study examined between-subject differences in overall levels of hormones, rather than changes per se, our results provide preliminary support for these predictions by showing that estrogen primarily impacts shared environmental influences on emotional eating.…”

“…Two independent raters then coded menstrual cycle phase and ovulation status (i.e. ovulatory versus anovulatory) based on changes in hormones across days (for more information on phase and ovulation coding, see Klump et al (2015)). …”

“…Interestingly, there were also novel shifts in the type of environmental risk factors that were important across the cycle (Klump et al, 2015). Although nonshared environmental risk factors (i.e., those that are unique to twins growing up in the same family) were prominent across all cycle phases, shared environmental factors (i.e., those that are common to twins raised in the same family) were two times higher in pre- as opposed to post-ovulation – in fact, all of the models showed essentially no shared environmental effects in post-ovulation, but significant (32%) shared environmental influences in pre-ovulation.…”