Table 3

Sunlight exposure and dietary vitamin D and breast cancer risk among white women, by region of residence: NHANES I Epidemiologic Follow-up Study, 1971–1975 to 1992

Low solar radiationaMedium solar radiationaHigh solar radiationa
Breast cancer casesMultivariate-adjusted RR (95% CI)bBreast cancer casesMultivariate adjusted RR (95% CI)bBreast cancer casesMultivariate-adjusted RR (95% CI)b
Sun exposure determined by physician
 Unimpressive381.0371.0181.0
 Moderate/considerable451.20 (0.77–1.86)300.71 (0.44–1.15)190.58 (0.30–0.11)
Actinic skin damage
 None491.0411.0231.0
 Minimal231.07 (0.64–1.78)190.98 (0.54–1.77)90.77 (0.34–1.73)
 Moderate/severe111.18 (0.59–2.36)70.77 (0.33–1.79)60.69 (0.27–1.78)
Dietary vitamin D (IU)
 <100361.0311.0171.0
 100–199180.97 (0.55–1.71)211.15 (0.66–2.01)121.20 (0.57–2.53)
 ≥200200.92 (0.53–1.59)130.91 (0.47–1.75)70.75 (0.31–1.84)
Combined recreational and occupational sun exposure
 Low151.091.081.0
 Medium440.53 (0.29–0.97)340.83 (0.39–1.76)190.54 (0.23–1.25)
 High90.40 (0.17–0.94)100.77 (0.31–1.93)40.35 (0.10–1.20)
MD sun exposure and dietary vitamin Dc
 Low sun and <200 IU251.0311.0141.0
 High sun and ≥200 IU101.13 (0.53–2.43)90.84 (0.40–1.77)30.36 (0.10–1.31)
  • a Level of solar radiation in state of longest residence.

  • b Adjusted for age, education, age at menarche, age at menopause, body mass index, frequency of alcohol consumption, and physical activity.