A prospective exploration of cognitive dietary restraint, subclinical ovulatory disturbances, cortisol, and change in bone density over two years in healthy young women

Cross-sectional studies have found associations among elevated cognitive dietary restraint (CDR), increased ovulatory disturbances, and lower bone mass, possibly mediated by cortisol.

To determine whether healthy young women with higher CDR have more menstrual cycles with subclinical ovulatory disturbances (SOD), elevated 24-h urinary free cortisol (UFC), and less positive 2-yr areal bone mineral density change (Delta-aBMD).

We conducted a 2-yr longitudinal study of 123 healthy, community-dwelling, nonobese, regularly menstruating women aged 19-35 yr.

Key variables were Three Factor Eating Questionnaire Restraint score, percent of cycles with anvoluation and/or luteal phase length <10 d (%SOD), UFC, and Delta-aBMD at the lumbar spine (L1-L4), total hip, and whole body. Anthropometrics, general stress, physical activity, and energy intake were measured. Adjusting for potential confounders, differences were examined by general linear modeling using median split of CDR score and %SOD.

Women with higher CDR had higher %SOD (56 vs. 34%, P < 0.001) and higher UFC (28.0 vs. 24.0 microg/d, P = 0.021). Delta-aBMD did not differ by CDR. Women with higher %SOD had less positive Delta-aBMD at L1-L4 (0.7 vs. 1.9%, P = 0.034) and hip (-0.6 vs. 0.9%, P = 0.001), and higher CDR score (8.7 vs. 7.1, P = 0.04). Physical activity, general stress, body mass index, and energy intake did not explain differences by CDR or %SOD. UFC was not associated with %SOD or Delta-aBMD.

Women with more frequent SOD reported higher CDR and experienced less positive Delta-aBMD. Although women with higher CDR had higher UFC, the mechanism linking CDR, SOD, and aBMD is not clear.