title: A prospective exploration of cognitive dietary restraint, subclinical ovulatory disturbances, cortisol, and change in bone density over two years in healthy young women.
abstract: BACKGROUND
  Cross-sectional studies have found associations among elevated cognitive dietary restraint (CDR), increased ovulatory disturbances, and lower bone mass, possibly mediated by cortisol.
  
  
  OBJECTIVE
  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).
  
  
  METHODS
  We conducted a 2-yr longitudinal study of 123 healthy, community-dwelling, nonobese, regularly menstruating women aged 19-35 yr.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Human Nutrition, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Bedford
authors.forename: Jerilynn C
authors.initials: JC
authors.lastname: Prior
authors.forename: Susan I
authors.initials: SI
authors.lastname: Barr
mesh_terms: D000328:Adult; D000886:Anthropometry; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D002149:Energy Intake; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000652:urine*; D008597:Menstrual Cycle / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology; D011446:Prospective Studies; D013315:Stress, Psychological; D011795:Surveys and Questionnaires; D016387:Women's Health
chemical_list: D006854:Hydrocortisone