TABLE 1.
Age-standardized characteristics of PMS cases and controls at baseline (1991): Nurses’ Health Study II PMS substudy, 1991–20051
| Characteristic | Cases (n = 1234) | Controls (n = 2426) |
| Age,2 y | 33.9 ± 4.2 | 34.5 ± 3.9 |
| BMI, kg/m2 | 24.6 ± 0.1 | 23.7 ± 0.1 |
| Age at menarche, y | 12.4 ± 0.04 | 12.5 ± 0.03 |
| Full-term pregnancies, n | 1.6 ± 0.03 | 1.7 ± 0.02 |
| Physical activity, MET-h/wk | 22.8 ± 1.6 | 23.4 ± 1.1 |
| Potassium intake, mg/d | 2921 ± 14.1 | 2897 ± 10.1 |
| Vitamin B-6 intake, mg/d | 8.7 ± 0.6 | 5.8 ± 0.4 |
| Vitamin D intake, IU/d | 398 ± 7.0 | 400 ± 5.0 |
| Calcium intake, mg/d | 1029 ± 11.8 | 1062 ± 8.4 |
| Alcohol intake, g/d | 3.1 ± 0.2 | 3.1 ± 0.1 |
| Caucasian, % | 96.8 | 97.2 |
| Ever used oral contraceptives, % | 85.5 | 77.2 |
| Current smoker, % | 12.6 | 7.1 |
| Ever used antidepressant medications,3 % | 15.5 | 7 |
| History of substantial childhood trauma, % | 14.1 | 8 |
1
Values are means ± SEs or percentages, unless otherwise indicated. All characteristics were calculated with the use of generalized linear models adjusted for the age of participants in 1991. MET-h, metabolic equivalent task hours; PMS, premenstrual syndrome.
2
Values are means ± SDs.
3
Use before PMS diagnosis (for cases).