Table 3.
Multivariate hazard ratios and 95% confidence intervals according to low/higha joint intake of nitrite or nitrate and vitamin C and ovarian cancer risk (n = 151 316)
| Joint intake of nitrate and/or nitrite intake and vitamin C | Low/high | Low/low | High/high | High/low | P joint interaction |
|---|---|---|---|---|---|
| Dietary vitamin C, median intake (mg/1000 kcal per day) | 195 | 84 | 195 | 84 | |
| Nitrate, total, median intake (mg/1000 kcal) | 32.9 | 32.9 | 76.7 | 76.7 | |
| Number of cases | 130 | 214 | 226 | 139 | |
| Multivariate HR (95% CI) | 1.00 | 1.12 (0.89–1.41) | 1.12 (0.89–1.39) | 1.12 (0.86–1.45) | 0.06 |
| Nitrite, total, median intake (mg/1000 kcal) | 0.56 | 0.56 | 0.79 | 0.79 | |
| Number of cases | 157 | 187 | 199 | 166 | |
| Multivariate HR (95% CI) | 1.00 | 1.02 (0.81–1.27) | 1.00 (0.81–1.24) | 1.07 (0.84–1.35) | 0.86 |
| Nitrite from plant sources, median (mg/1000 kcal) | 0.35 | 0.35 | 0.57 | 0.57 | |
| Number of cases | 141 | 217 | 215 | 136 | |
| Multivariate HR (95% CI) | 1.00 | 1.18 (0.95–1.48) | 1.09 (0.88–1.35) | 0.96 (0.75–1.24) | 0.68 |
| Nitrite from animal sources, median (mg/1000 kcal) | 0.13 | 0.13 | 0.25 | 0.25 | |
| Number of cases | 187 | 147 | 169 | 206 | |
| Multivariate HR (95% CI) | 1.00 | 0.94 (0.75–1.18) | 1.02 (0.82–1.25) | 1.13 (0.92–1.39) | 0.69 |
| Nitrate and nitrite from processed meat, median (mg/1000 kcal) | 0.19 | 0.19 | 0.68 | 0.68 | |
| Number of cases | 196 | 144 | 160 | 209 | |
| Multivariate HR (95% CI) | 1.00 | 0.98 (0.79–1.23) | 1.04 (0.84–1.28) | 1.11 (0.90–1.36) | 0.12 |
Adjusted for age (continuous), race (nonHispanic White, nonHispanic Black, other, and missing), total energy intake (continuous), family history of cancer, body mass index ( <25, 25–29.9, 30–34.9, ≥35 kg/m2), education ( < high school–high school graduate, posthigh school other than college, some college, college graduate, postgraduate, and missing), smoking status (current, former, never, missing), menopausal status (premenopausal, natural: <45 years, natural: 45–49 years, natural: 50–54 years, natural: >55 years, surgical, unknown), parity (nulliparous, 1, 2, or 3 or more children), age at menarche (≤12 years, 13–14 years, ≥15 years).
CI, confidence interval; HR, hazards ratio.
Low–high distinctions based on median intake values.