Table 2.
The relative risk for incident non-melanoma skin cancer according to the frequency of citrus consumption among Women’s Health Initiative participants (n = 49,007).
| Serving Category | p-Trend | |||||
|---|---|---|---|---|---|---|
| Total Citrus | <2/wk | 2–4/wk | 5–6/wk | 1–1.4/d | ≥1.5/d | |
| No. of cases (%) | 2275 (16.3) | 1903 (17.5) | 873 (17.5) | 2257 (19.1) | 1334 (18.3) | |
| Age-adjusted RR (95% CI) | (ref) | 1.06 (1.01, 1.13) | 1.06 (0.98, 1.14) | 1.15 (1.09, 1.22) | 1.11 (1.04, 1.18) | <0.001 |
| Model 1: Minimally-adjusted RR (95% CI) | (ref) | 1.02 (0.96, 1.08) | 1.00 (0.93, 1.07) | 1.08 (1.03, 1.14) | 1.03 (0.97, 1.10) | 0.065 |
| Model 2: Maximally-adjusted RR (95% CI) | (ref) | 1.01 (0.96, 1.07) | 1.00 (0.93, 1.07) | 1.08 (1.02, 1.14) | 1.02 (0.96, 1.09) | 0.127 |
| Citrus Fruit | Never | <1/wk | 1/wk | 2–4/wk | ≥5/wk | |
| No. of cases (%) | 1362 (16.4) | 3295 (17.6) | 1156 (18.2) | 1257 (18.2) | 1572 (18.0) | |
| Age-adjusted RR (95% CI) | (ref) | 1.07 (1.01, 1.13) | 1.09 (1.02, 1.17) | 1.09 (1.02, 1.17) | 1.08 (1.01, 1.15) | 0.453 |
| Model 1: Minimally-adjusted RR (95% CI) | (ref) | 1.01 (0.96, 1.07) | 1.00 (0.93, 1.08) | 1.01 (0.94, 1.08) | 0.98 (0.92, 1.05) | 0.295 |
| Model 2: Maximally-adjusted RR (95% CI) | (ref) | 1.01 (0.95, 1.07) | 0.99 (0.92, 1.06) | 1.00 (0.93, 1.07) | 0.97 (0.91, 1.04) | 0.337 |
| Citrus Juice | <1/wk | 1/wk | 2–4/wk | 5–6/wk | ≥1/d | |
| No. of cases (%) | 3572 (16.7) | 768 (17.4) | 1531 (18.4) | 508 (17.0) | 2263 (19.0) | |
| Age-adjusted RR (95% CI) | (ref) | 1.04 (0.97, 1.11) | 1.08 (1.02, 1.14) | 1.01 (0.93, 1.10) | 1.12 (1.07, 1.18) | <0.001 |
| Model 1: Minimally-adjusted RR (95% CI) | (ref) | 1.02 (0.95, 1.09) | 1.07 (1.01, 1.13) | 0.98 (0.90, 1.07) | 1.08 (1.03, 1.14) | 0.002 |
| Model 2: Maximally-adjusted RR (95% CI) | (ref) | 1.03 (0.95, 1.10) | 1.06 (1.00, 1.12) | 0.98 (0.90, 1.07) | 1.08 (1.02, 1.13) | 0.007 |
| Non-Citrus Fruit and Juice | <0.75/d | 0.75–1.2/d | 1.3–1.9/d | 2.0–2.9/d | ≥3/d | |
| No. of cases (%) | 1321 (16.2) | 1738 (17.4) | 2126 (18.2) | 1926 (18.3) | 1531 (17.9) | |
| Age-adjusted RR (95% CI) | (ref) | 1.06 (1.00, 1.14) | 1.11 (1.05, 1.19) | 1.11 (1.04, 1.19) | 1.09 (1.02, 1.16) | 0.029 |
| Model 1: Minimally-adjusted RR (95% CI) | (ref) | 1.02 (0.95, 1.09) | 1.04 (0.97, 1.10) | 1.02 (0.96, 1.09) | 0.99 (0.92, 1.06) | 0.440 |
| Model 2: Maximally-adjusted RR (95% CI) | (ref) | 1.01 (0.95, 1.08) | 1.03 (0.96, 1.09) | 1.00 (0.93, 1.07) | 0.96 (0.89, 1.03) | 0.116 |
Model 1: adjusted for age (continuous), BMI (<25.0, 25.0–29.9, 30.0–34.9, ≥35.0 kg/m2), education (less than high school graduate, high school graduate, some college, and college graduate), physical activity (inactive, low activity, moderate activity, and high activity), alcohol consumption (continuous), regional solar radiation (300–325, 350, 375–380, 400–430, and 475–500 Langleys), skin reaction to sun (no burns, with or without tanning; burns, and with or without tanning), average daily time outdoors currently (<30 min, 30 min–2 h, and 2+ h), and sunscreen SPF use (none, something but does not know, SPF 2–14, SPF 15–24, and SPF 25+). Model 2: Model 1 plus adjustment for the total calorie intake (continuous), coffee consumption (continuous), smoking (never, past, and current), hormone therapy status (never, past, and current), and average daily time outdoors in summer as a child (<30 min, 30 min–2 h, and 2+ h).