Table 2.

HRs of breast cancer according to: tertiles of energy-adjusted vitamin D and supplement intakes, quartiles of UVR dose exposure and latitudes at the region of residence (n = 67,721) E3N cohort 1993 to 2005

Entire PopulationPremenopausalPostmenopausal
Median valuePerson- YearsCasesHRa (CI 95%)Person- YearsCasesHRa (CI 95%)Person- YearsCasesHRa (CI 95%)
Vitamin D, IU/db
 < 8064.4230,702927(Reference)48,676212(Reference)182,026715(Reference)
 80–11396228,3759471.02 (0.93–1.11)48,6491990.92 (0.76–1.12)179,7267481.04 (0.94–1.16)
 >113143.2224,9158870.94 (0.86–1.03)44,3912031.03 (0.85–1.25)180,5246840.92 (0.83–1.02)
 Supplementedunknown27,5311100.90 (0.72–1.12)1,19540.68 (0.25–1.87)26,3361060.91 (0.73–1.14)
P value for trend0.13 0.9 0.08
Mean daily UVR dose exposure at place of residence, kJ/m2c
 < 2.42.3182,934756(Reference)37,024168(Reference)145,910588(Reference)
 2.4–2.52.4177,0407071.01 (0.91–1.12)36,5151621.06 (0.85–1.31)140,5255450.99 (0.88–1.11)
 2.5–2.72.6178,8547460.95 (0.86–1.06)37,1541691.01 (0.81–1.25)141,7005770.94 (0.84–1.05)
 >2.73.0172,6956620.91 (0.82–0.99)32,2181190.85 (0.67–1.08)140,4775430.92 (0.82–0.98)
P value for trend0.060.20.05
Latitudes at place of residencec
 >48.6°N49.0234,174896(Reference)45,638173(Reference)188,536723(reference)
 45.8–48.6°N47.4238,4359640.98 (0.90–1.08)48,2212211.01 (0.83–1.21)190,2147430.98 (0.88–1.08)
 < 45.8° N44.0238,9141,0110.90 (0.82–0.98)49,0522240.89 (0.73–1.09)189,8627870.90 (0.81–1.00)
P value for trend0.020.20.06
  • aAdjusted for menopausal status (time dependent), BMI (<20/20–25/>25 kg/m2), physical activity in 1993 (in Met-h/week; <34/34–46/46–62/>62), age at menopause (<47/47–54/>54 years among postmenopausal women only), age at menarche, parity (number of full-term pregnancies), previous use of oral contraceptives (ever/never), use of menopausal hormone therapy (never, current, past, unknown, time-dependent variable, among postmenopausal women only), daily calcium intake (< 868.4/868.4–1,092.5/>1,092.5 mg/day), current use of calcium supplement (yes, no, time-dependent variable), alcohol intake (g/day), total energy intake without alcohol (kcal/day), university degree (yes/no), previous family history of breast cancer (yes/no), previous personal history of benign breast disease (ever, never, time-dependent variable), previous history of mammographic exam (yes, no, time-dependent variable), sun burn resistance (low, medium, high), skin complexion (very fair, fair, medium, dark, very dark).

  • bHR were adjusted for the same covariates as a plus vitamin D dietary [<80/80–113/>113 (IU/day)] and supplement intakes.

  • cHR were adjusted for the same covariates as a plus UVR dose exposure at place of residence (<2.4/2.4–2.5/2.5–2.7/> 2.7 kJ/m2/day).