Calcium and vitamin D intake and risk of incident premenstrual syndrome.
BACKGROUND
Premenstrual syndrome (PMS) is one of the most common disorders of premenopausal women. Studies suggest that blood calcium and vitamin D levels are lower in women with PMS and that calcium supplementation may reduce symptom severity, but it is unknown whether these nutrients may prevent the initial development of PMS.


METHODS
We conducted a case-control study nested within the prospective Nurses' Health Study II cohort. Participants were a subset of women aged 27 to 44 years and free from PMS at baseline in 1991, including 1057 women who developed PMS over 10 years of follow-up and 1968 women reporting no diagnosis of PMS and no or minimal menstrual symptoms. Intake of calcium and vitamin D was measured in 1991, 1995, and 1999 by a food frequency questionnaire.


RESULTS
After adjustment for age, parity, smoking status, and other risk factors, women in the highest quintile of total vitamin D intake (median, 706 IU/d) had a relative risk of 0.59 (95% confidence interval, 0.40-0.86) compared with those in the lowest quintile (median, 112 IU/d) (P = .01 for trend). The intake of calcium from food sources was also inversely related to PMS; compared with women with a low intake (median, 529 mg/d), participants with the highest intake (median, 1283 mg/d) had a relative risk of 0.70 (95% confidence interval, 0.50-0.97) (P = .02 for trend). The intake of skim or low-fat milk was also associated with a lower risk (P<.001).


CONCLUSIONS
A high intake of calcium and vitamin D may reduce the risk of PMS. Large-scale clinical trials addressing this issue are warranted. Given that calcium and vitamin D may also reduce the risk of osteoporosis and some cancers, clinicians may consider recommending these nutrients even for younger women.
Bertone-Johnson
Elizabeth R
ER
Department of Public Health, University of Massachusetts, Amherst 01003-9304, USA. ebertone@schoolph.umass.edu
Hankinson
Susan E
SE
Bendich
Adrianne
A
Johnson
Susan R
SR
Willett
Walter C
WC
Manson
Joann E
JE
D000328:Adult; D002118:Calcium / Q000097:blood* / Q000627:therapeutic use; D016022:Case-Control Studies; D003611:Dairy Products; D004032:Diet; D015930:Diet Records; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D011293:Premenstrual Syndrome / Q000097:blood* / Q000628:therapy; D011446:Prospective Studies; D012307:Risk Factors; D014807:Vitamin D / Q000097:blood* / Q000627:therapeutic use
D014807:Vitamin D; D002118:Calcium