Within-Person Changes in Daily Ovarian Hormone Levels Influence Genetic Effects on Emotional Eating in Women

Ovarian hormones (i.e., estradiol, progesterone) show robust phenotypic associations with binge eating and related behaviors (e.g., emotional eating) in females. Recent research suggests these associations may be due to ovarian hormone effects on genetic and environmental influences on dysregulated eating. However, no research has yet examined how within-person fluctuations in hormone levels impact genetic/environmental influences on day-to-day changes in dysregulated eating from an individual's own mean. This omission is critical because phenotypic associations between ovarian hormones and dysregulated eating are strongest at a within-person level in adult women, suggesting potentially unique and important within-person effects.

Participants from same-sex female twin pairs (N = 468) from the MSU Twin Registry provided measures of ovarian hormones and emotional eating daily for 49 consecutive days. We used continuous twin moderation models to examine how within-person centered estradiol and progesterone impacted genetic/environmental influences on within-person shifts in emotional eating.

Within-person fluctuations in estradiol and progesterone significantly moderated genetic influences on within-person changes in emotional eating. Stronger genetic influences were observed when the ratio of within-person estradiol to progesterone was in the moderate range.

Cyclic, within-person changes in ovarian hormones may contribute to phenotypic changes in dysregulated eating across the menstrual cycle by dynamically regulating expression of underlying genetic risk. Genetic influences may be particularly pronounced under the hormonal conditions characteristic of the mid-luteal phase (i.e., moderate estradiol and progesterone).