Table 1.

Age-standardized characteristics of study population at beginning of follow-up period, by clinical depression statusa (NHS: 2000, NHSII: 2003)

NHSNHSII
Not depressed n= 61,818Clinically depressed n= 4,874Not depressed n= 77,132Clinically depressed n= 12,688
Age, yearsb66.4 (7.1)65.2 (7.0)48.3 (4.7)48.7 (4.6)
White race, %97.598.595.797.5
Number of times reported antidepressant use, %
 0, %91.922.980.716.3
 1, %4.327.26.621.4
 2, %2.020.96.918.8
 ≥3, %1.829.05.843.6
Number of times with severe depressive symptoms, as assessed by MHI-5
 0, %93.269.986.660.5
 1, %4.816.09.122.2
 2, %1.48.43.111.2
 ≥3, %0.75.71.36.1
History of breast cancer in first-degree relative, %17.417.214.715.5
Mammogram in previous 2 years, %93.394.485.385.2
Age at menarche
 ≤12, %35.132.354.656.9
 13, %39.641.427.625.9
 14+, %25.326.317.817.2
Nulliparous, %5.26.017.119.8
Age at first birth, yearsc25.1 (3.3)24.9 (3.3)26.6 (4.7)26.1 (4.9)
Parityc3.2 (1.5)3.1 (1.4)2.3 (1.0)2.2 (0.9)
Breastfeeding history
 None/<1 month, %47.145.619.119.9
 1 month–<1 year, %34.236.234.136.9
 1–<2 years, %12.212.524.724.0
 ≥2 years, %6.65.722.119.2
Postmenopausal, %98.898.942.149.0
Age at menopause, yearsd
 <50 years, %42.344.660.966.6
 50–<55 years, %48.547.636.931.8
 ≥55 years, %9.27.82.21.6
History of benign breast disease, %49.961.250.258.0
Current oral contraceptive use, %86.790.8
Type of postmenopausal hormone therapy use
 Premenopausal, %1.41.362.456.0
 Never user, %24.213.015.013.3
 Unopposed estrogen, %34.444.311.416.6
 Estrogen + progesterone, %30.129.08.49.9
 Other, %10.012.42.84.1
Body mass index, kg/m2
 <25 kg/m2, %42.134.746.634.2
 25–<30 kg/m2, %34.933.228.327.6
 ≥30 kg/m2, %23.032.225.138.2
Early life somatotypee2.7 (1.2)2.8 (1.2)2.9 (1.1)3.1 (1.2)
Diabetes, %8.713.03.66.8
Total physical activity, MET-hrs/wk
 <3 MET-hrs/wk, %24.232.719.425.9
 3–<9 MET-hrs/wk, %22.424.120.922.2
 9–<18 MET-hrs/wk, %20.317.820.019.0
 18–<27 MET-hrs/wk, %12.710.213.311.8
 ≥27 MET-hrs/wk, %20.415.326.421.1
Alcohol intake, g/df
 None, %41.649.735.740.9
 <5 g/d, %30.127.032.631.5
 5-<15 g/d, %19.415.620.717.2
 ≥15 g/d, %9.07.710.910.4
Alternative healthy eating index scoref54.2 (10.5)53.7 (10.8)54.6 (13.2)53.4 (13.1)
Smoking status
 Never smoker, %45.039.366.057.0
 Past smoker, %45.949.925.730.4
 Current smoker, %9.010.98.312.6
  • 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.