Table 4.
Melanoma risk according to frequency of total citrus consumption stratified by skin color among study participants in the UK Biobank.
| Total citrus serving category | ||||||
|---|---|---|---|---|---|---|
| Melanoma risk factor | None | >0-½ serving | >½-1 serving | >1-2 servings | >2 servings | p-trend |
| Skin color | ||||||
| Dark/light olive | ||||||
| N (number of cases) | 16,820 (69) | 7,419 (20) | 9,160 (37) | 5,312 (23) | 1,423 (5) | |
| Age-adjusted OR (95% CI) | 1.00 | 0.64 (0.38–1.03) | 0.93 (0.62–1.39) | 1.00 (0.61–1.58) | 0.81 (0.52–2.30) | 0.85 |
| Multivariable-adjusted OR1 (95% CI)1 | 1.00 | 0.64 (0.38–1.03) | 0.95 (0.63–1.41) | 1.02 (0.62–1.62) | 0.84 (0.29–1.89) | 0.95 |
| Multivariable-adjusted OR2 (95% CI)2 | 1.00 | 0.48 (0.23–0.89) | 0.84 (0.50–1.36) | 0.84 (0.44–1.50) | 0.68 (0.17–1.89) | 0.45 |
| Fair/very fair | ||||||
| N (number of cases) | 65,477 (537) | 29,409 (257) | 36,669 (361) | 21,428 (206) | 5,847 (77) | |
| Age-adjusted OR (95% CI) | 1.00 | 1.05 (0.90–1.22) | 1.18 (1.03–1.34) | 1.14 (0.97–1.34) | 1.56 (1.22–1.98) | 0.0005 |
| Multivariable-adjusted OR1 (95% CI)1 | 1.00 | 1.03 (0.88–1.19) | 1.14 (0.99–1.30) | 1.11 (0.94–1.30) | 1.51 (1.18–1.92) | 0.0029 |
| Multivariable-adjusted OR2 (95% CI)2 | 1.00 | 1.05 (0.87–1.26) | 1.10 (0.93–1.30) | 1.17 (0.96–1.42) | 1.75 (1.31–2.29) | 0.0015 |
Note: Skin color was the only melanoma risk factor with evidence of effect modification in our analysis. Bold font indicates statistical significance
Further adjusted for: sex (male, female), education (categorical – college or university degree; Advanced level/Advanced Subsidiary level; Ordinary level/General Certificate of Secondary Education, Certificate of Secondary Education; National Vocational Qualification, Higher National Diploma, or Higher National Certificate; other professional degree; none of the preceding), income (categorical – less than £30,999, £31,000 - £51,999, £52,000 and up, missing), physical activity (categorical – low, moderate, high, missing), BMI (continuous), smoking status (categorical – never, previous, current), alcohol intake (categorical – never/special occasions only, < 3 times/week, ≥ 3 times/week), and total energy intake (quartiles – KJ).
Additionally adjusted for: coffee intake (continuous – mean cups/day), tanning ability (categorical – never tan, mildly/occasionally tan, moderately tan, very tanned), childhood sunburn occasions (continuous), natural hair color (categorical – red/blonde, light brown, dark brown/black, other), skin color (categorical – dark/light olive, fair, very fair), average time spent outdoors in summer (continuous – hours/day), sunlamp/solarium use (continuous – times/year), sun/UV protection use (categorical – always, most of the time, sometimes, never/rarely), and history of non-melanoma skin cancer (yes, no).
Abbreviation: OR, odds ratio; CI, confidence interval