Age-standardized characteristics of study population at beginning of follow-up period, by clinical depression statusa (NHS: 2000, NHSII: 2003)
| NHS | NHSII | |||
|---|---|---|---|---|
| Not depressed n= 61,818 | Clinically depressed n= 4,874 | Not depressed n= 77,132 | Clinically depressed n= 12,688 | |
| Age, yearsb | 66.4 (7.1) | 65.2 (7.0) | 48.3 (4.7) | 48.7 (4.6) |
| White race, % | 97.5 | 98.5 | 95.7 | 97.5 |
| Number of times reported antidepressant use, % | ||||
| 0, % | 91.9 | 22.9 | 80.7 | 16.3 |
| 1, % | 4.3 | 27.2 | 6.6 | 21.4 |
| 2, % | 2.0 | 20.9 | 6.9 | 18.8 |
| ≥3, % | 1.8 | 29.0 | 5.8 | 43.6 |
| Number of times with severe depressive symptoms, as assessed by MHI-5 | ||||
| 0, % | 93.2 | 69.9 | 86.6 | 60.5 |
| 1, % | 4.8 | 16.0 | 9.1 | 22.2 |
| 2, % | 1.4 | 8.4 | 3.1 | 11.2 |
| ≥3, % | 0.7 | 5.7 | 1.3 | 6.1 |
| History of breast cancer in first-degree relative, % | 17.4 | 17.2 | 14.7 | 15.5 |
| Mammogram in previous 2 years, % | 93.3 | 94.4 | 85.3 | 85.2 |
| Age at menarche | ||||
| ≤12, % | 35.1 | 32.3 | 54.6 | 56.9 |
| 13, % | 39.6 | 41.4 | 27.6 | 25.9 |
| 14+, % | 25.3 | 26.3 | 17.8 | 17.2 |
| Nulliparous, % | 5.2 | 6.0 | 17.1 | 19.8 |
| Age at first birth, yearsc | 25.1 (3.3) | 24.9 (3.3) | 26.6 (4.7) | 26.1 (4.9) |
| Parityc | 3.2 (1.5) | 3.1 (1.4) | 2.3 (1.0) | 2.2 (0.9) |
| Breastfeeding history | ||||
| None/<1 month, % | 47.1 | 45.6 | 19.1 | 19.9 |
| 1 month–<1 year, % | 34.2 | 36.2 | 34.1 | 36.9 |
| 1–<2 years, % | 12.2 | 12.5 | 24.7 | 24.0 |
| ≥2 years, % | 6.6 | 5.7 | 22.1 | 19.2 |
| Postmenopausal, % | 98.8 | 98.9 | 42.1 | 49.0 |
| Age at menopause, yearsd | ||||
| <50 years, % | 42.3 | 44.6 | 60.9 | 66.6 |
| 50–<55 years, % | 48.5 | 47.6 | 36.9 | 31.8 |
| ≥55 years, % | 9.2 | 7.8 | 2.2 | 1.6 |
| History of benign breast disease, % | 49.9 | 61.2 | 50.2 | 58.0 |
| Current oral contraceptive use, % | — | — | 86.7 | 90.8 |
| Type of postmenopausal hormone therapy use | ||||
| Premenopausal, % | 1.4 | 1.3 | 62.4 | 56.0 |
| Never user, % | 24.2 | 13.0 | 15.0 | 13.3 |
| Unopposed estrogen, % | 34.4 | 44.3 | 11.4 | 16.6 |
| Estrogen + progesterone, % | 30.1 | 29.0 | 8.4 | 9.9 |
| Other, % | 10.0 | 12.4 | 2.8 | 4.1 |
| Body mass index, kg/m2 | ||||
| <25 kg/m2, % | 42.1 | 34.7 | 46.6 | 34.2 |
| 25–<30 kg/m2, % | 34.9 | 33.2 | 28.3 | 27.6 |
| ≥30 kg/m2, % | 23.0 | 32.2 | 25.1 | 38.2 |
| Early life somatotypee | 2.7 (1.2) | 2.8 (1.2) | 2.9 (1.1) | 3.1 (1.2) |
| Diabetes, % | 8.7 | 13.0 | 3.6 | 6.8 |
| Total physical activity, MET-hrs/wk | ||||
| <3 MET-hrs/wk, % | 24.2 | 32.7 | 19.4 | 25.9 |
| 3–<9 MET-hrs/wk, % | 22.4 | 24.1 | 20.9 | 22.2 |
| 9–<18 MET-hrs/wk, % | 20.3 | 17.8 | 20.0 | 19.0 |
| 18–<27 MET-hrs/wk, % | 12.7 | 10.2 | 13.3 | 11.8 |
| ≥27 MET-hrs/wk, % | 20.4 | 15.3 | 26.4 | 21.1 |
| Alcohol intake, g/df | ||||
| None, % | 41.6 | 49.7 | 35.7 | 40.9 |
| <5 g/d, % | 30.1 | 27.0 | 32.6 | 31.5 |
| 5-<15 g/d, % | 19.4 | 15.6 | 20.7 | 17.2 |
| ≥15 g/d, % | 9.0 | 7.7 | 10.9 | 10.4 |
| Alternative healthy eating index scoref | 54.2 (10.5) | 53.7 (10.8) | 54.6 (13.2) | 53.4 (13.1) |
| Smoking status | ||||
| Never smoker, % | 45.0 | 39.3 | 66.0 | 57.0 |
| Past smoker, % | 45.9 | 49.9 | 25.7 | 30.4 |
| Current smoker, % | 9.0 | 10.9 | 8.3 | 12.6 |
NOTE: Values are means (SD) or percentages and are standardized to the age distribution of the study population. Values of polytomous variables may not sum to 100% due to rounding.
↵aClinical depression defined as self-reported of having been diagnosed with depression by a physician or other medical professional.
↵bValue is not age adjusted.
↵cAmong parous women only.
↵dAmong postmenopausal women with a natural or surgical menopause.
↵eAverage of reported somatotype at ages 10 and 20.
↵fBased on data from 1998 (NHS) or 2001 (NHSII) questionnaire.