Table 3.
Vitamin supplement use and risk of endometrial cancer, Nurses’ Health Study cohort (1980–2006)
| Relative Risks (95% CI) | Ptrend | ||||||
|---|---|---|---|---|---|---|---|
| Vitamin supplements | |||||||
| Multivitamins | Numbers used /week | 0 | 2 or less | 3–5 | 6–9 | 10+ | |
| Case # | 391 | 19 | 51 | 189 | 19 | ||
| RR (95% CI) | |||||||
| Age adjusted* | 1.00 | 0.95 (0.60–1.51) | 1.03 (0.77–1.38) | 0.92 (0.77–1.10) | 1.10 (0.69–1.75) | 0.57 | |
| Multi-adjusted† | 1.00 | 0.96 (0.60–1.52) | 1.05 (0.78–1.40) | 0.92 (0.77–1.10) | 1.09 (0.69–1.73) | 0.54 | |
| Vitamin C | |||||||
| supplements | mg/day | 0 | <400 | 400–700 | 750–1250 | 1300 | |
| Case # | 458 | 28 | 110 | 53 | 20 | ||
| RR (95% CI) | |||||||
| Age adjusted* | 1.00 | 0.83 (0.56–1.21) | 1.04 (0.85–1.29) | 0.86 (0.64–1.14) | 1.23 (0.78–1.92) | 0.90 | |
| Multi-adjusted† | 1.00 | 0.83 (0.57–1.22) | 1.05 (0.85–1.30) | 0.86 (0.65–1.15) | 1.23 (0.79–1.93) | 0.96 | |
| Vitamin E | IU/day | 0 | <250 | 300–500 | 600+ | ||
| supplements | |||||||
| Case # | 472 | 41 | 128 | 28 | |||
| RR (95% CI) | |||||||
| Age adjusted* | 1.00 | 1.12 (0.82–1.55) | 0.95 (0.78–1.17) | 0.91 (0.62–1.33) | 0.59 | ||
| Multi-adjusted† | 1.00 | 1.16 (0.84–1.60) | 0.95 (0.78–1.17) | 0.88 (0.60–1.30) | 0.55 | ||
| Duration of used vitamin supplements | |||||||
| Multivitamins | Categories | 0 | <24 months | 24–59 months | 60+ months | ||
| Case # | 139 | 27 | 375 | 128 | |||
| RR (95% CI) | |||||||
| Age adjusted* | 1.00 | 0.65 (0.43–0.98) | 0.98 (0.78–1.24) | 1.02 (0.77–1.36) | 0.93 | ||
| Multi-adjusted† | 1.00 | 0.64 (0.42–0.97) | 0.98 (0.77–1.23) | 1.01 (0.76–1.35) | 0.99 | ||
| Vitamin A | Case # | 595 | 22 | 43 | 9 | ||
| RR (95% CI) | |||||||
| Age adjusted* | 1.00 | 1.04 (0.68–1.59) | 1.07 (0.78–1.45) | 1.22 (0.63–2.35) | 0.52 | ||
| Multi-adjusted† | 1.00 | 1.03 (0.67–1.57) | 1.08 (0.79–1.47) | 1.21 (0.62–2.34) | 0.49 | ||
| Vitamin C | Case # | 377 | 63 | 144 | 85 | ||
| RR (95% CI) | |||||||
| Age adjusted* | 1.00 | 0.93 (0.71–1.21) | 1.06 (0.87–1.29) | 1.06 (0.83–1.36) | 0.55 | ||
| Multi-adjusted† | 1.00 | 0.90 (0.69–1.17) | 1.05 (0.86–1.27) | 1.08 (0.85–1.39) | 0.53 | ||
| Vitamin E | Case # | 182 | 56 | 391 | 40 | ||
| RR (95% CI) | |||||||
| Age adjusted* | 1.00 | 1.04 (0.77–1.41) | 1.18 (0.95–1.45) | 1.07 (0.73–1.56) | 0.21 | ||
| Multi-adjusted† | 1.00 | 1.02 (0.75–1.38) | 1.18 (0.95–1.46) | 1.10 (0.75–1.61) | 0.17 | ||
Adjusted for age and follow-up period
Adjusted for total energy (continuous), smoking [never(reference), past, current], oral contraceptive use [never (reference), < 3 years, 3–5 years, > 5 years], postmenopausal hormone use [premenopausal, postmenopausal never(reference), past, current E only, current E+P], age at menopause [pre/unknown menopause, <45 yr, 45–46 yr, 47–48 yr (reference), 49–50 yr, 51–52 yr, 53+ yr] parity [nulliparous (reference), 1–2 & age at last birth<30, 1–2 & age at last birth>=30, 3–4 & age at last birth<30, 3–4 & age at last birth>=30, 5+], age at menarche [< 12, 12 (reference), > 12], hypertension (yes, no), diabetes (yes, no), BMI (continuous).