Table 4.
Hazard Ratio (and 95% CI) of skin cancer by total niacin intake among participants without hypercholesterolemia in the NHS (1984–2010) and HPFS (1986–2010)
| Quintile of total niacin intake |
p for trend |
|||||
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | ||
| BCC | ||||||
| NHS | ||||||
| No. of cases/person-years | 1,252/175,822 | 1,366/177,761 | 1,327/166,675 | 1,443/164,418 | 1,354/160,764 | |
| Age-adjusted | 1 (referent) | 1.07 (0.99, 1.15 | 1.11 (1.03, 1.20) | 1.20 (1.11, 1.30) | 1.14 (1.06, 1.24) | 0.002 |
| Multivariate-adjusted1 | 1 (referent) | 1.01 (0.93, 1.09) | 1.02 (0.94, 1.10) | 1.07 (0.99, 1.15) | 1.00 (0.93, 1.09) | 0.97 |
| HPFS | ||||||
| No. of cases/person-years | 1,105/108,366 | 1,148/105,728 | 1,118/99,163 | 1,224/94,199 | 1,130/90,271 | |
| Age-adjusted | 1 (referent) | 1.08 (0.99, 1.18) | 1.11 (1.02, 1.20) | 1.23 (1.13, 1.34) | 1.19 (1.09, 1.29) | 0.0002 |
| Multivariate-adjusted1 | 1 (referent) | 1.04 (0.95, 1.13) | 1.02 (0.94, 1.11) | 1.12 (1.03, 1.21) | 1.09 (1.00, 1.19) | 0.03 |
| Pooled2 | ||||||
| Age-adjusted | 1 (referent) | 1.08 (1.02, 1.14) | 1.11 (1.05, 1.17) | 1.22 (1.15 1.28) | 1.16 (1.10, 1.23) | <0.0001 |
| Multivariate-adjusted1 | 1 (referent) | 1.02 (0.97, 1.08) | 1.02 (0.96, 1.08) | 1.09 (1.03 1.16) | 1.04 (0.96, 1.13) | 0.24 |
| Squamous cell cancer | ||||||
| NHS | ||||||
| No. of cases/person-years | 124/176,482 | 114/178,480 | 111/167,381 | 92/165,187 | 110/161,527 | |
| Age-adjusted | 1 (referent) | 0.90 (0.70, 1.16) | 0.95 (0.73, 1.23) | 0.80 (0.61, 1.05) | 0.96 (0.74, 1.24) | 0.95 |
| Multivariate-adjusted1 | 1 (referent) | 0.81 (0.63, 1.05) | 0.82 (0.63, 1.06) | 0.68 (0.52, 0.90) | 0.80 (0.61, 1.03) | 0.25 |
| HPFS | ||||||
| No. of cases/person-years | 138/109,303 | 133/106,706 | 130/100,099 | 135/95,180 | 107/91,198 | |
| Age-adjusted | 1 (referent) | 1.02 (0.80, 1.29) | 1.04 (0.81, 1.31) | 1.08 (0.85, 1.36) | 0.90 (0.70, 1.16) | 0.32 |
| Multivariate-adjusted1 | 1 (referent) | 0.94 (0.74, 1.20) | 0.93 (0.72, 1.18) | 0.93 (0.73, 1.19) | 0.80 (0.74, 1.20) | 0.09 |
| Pooled2 | ||||||
| Age-adjusted | 1 (referent) | 0.96 (0.81, 1.14) | 0.99 (0.83, 1.18) | 0.94 (0.70, 1.25) | 0.93 (0.78, 1.11) | 0.39 |
| Multivariate-adjusted1 | 1 (referent) | 0.88 (0.74, 1.05) | 0.88 (0.73, 1.05) | 0.80 (0.59, 1.09) | 0.80 (0.67, 0.96) | 0.04 |
| Melanoma | ||||||
| NHS | ||||||
| No. of cases/person-years | 47/176,543 | 63/178,526 | 46/167,435 | 64/165,214 | 50/161,574 | |
| Age-adjusted | 1 (referent) | 1.30 (0.89, 1.90) | 1.02 (0.68, 1.90) | 1.43 (0.98, 2.08) | 1.14 (0.77, 1.70) | 0.75 |
| Multivariate-adjusted1 | 1 (referent) | 1.18 (0.80, 1.72) | 0.92 (0.61, 1.38) | 1.28 (0.87, 1.87) | 1.03 (0.68, 1.54) | 0.98 |
| HPFS | ||||||
| No. of cases/person-years | 44/109,383 | 44/106,775 | 56/100,161 | 31/95,279 | 56/91,242 | |
| Age-adjusted | 1 (referent) | 1.05 (0.69, 1.60) | 1.41 (0.95, 2.10) | 0.80 (0.50, 1.27) | 1.51 (1.02, 2.25) | 0.06 |
| Multivariate-adjusted1 | 1 (referent) | 1.01 (0.66, 1.55) | 1.35 (0.90, 2.01) | 0.73 (0.46, 1.16) | 1.42 (0.95, 2.13) | 0.11 |
| Pooled2 | ||||||
| Age-adjusted | 1 (referent) | 1.18 (0.89, 1.57) | 1.20 (0.87, 1.66) | 1.09 (0.61, 1.92) | 1.32 (0.99, 1.74) | 0.09 |
| Multivariate-adjusted1 | 1 (referent) | 1.10 (0.83 1.46) | 1.11 (0.76, 1.62) | 0.98 (0.57, 1.70) | 1.21 (0.88, 1.67) | 0.21 |
Adjusted for family history of melanoma (yes vs. no), natural hair color (red, blonde, light brown, dark brown and black), number of arm moles (0, 1–2, 3–9 and ≥10), skin reaction to sun exposure as a child/adolescent (none/some redness, burn and painful burn/blisters), number of lifetime blistering sunburns (0, 1–4, 5–9 and ≥10), average time spent in direct sunlight since high school (<2, 2–5, 6–9 and ≥10 hr/wk), cumulative UV flux since baseline (quintiles), body mass index (<25.0, 25.0–29.9, 30.0–34.9 and ≥35.0 kg/m2), physical activity (quintiles), smoking status (never, past, current with 1–14, 15–24 or ≥25 cigarettes/d), intakes of total energy (quintiles), alcohol (0, 0.1–4.9, 5.0–9.9, 10.0–19.9 and ≥20.0 g/d) and citrus intake (quintiles). Analyses for women were also adjusted for menopausal status and postmenopausal hormone use.
The multivariate-adjusted HR from each cohort were combined with meta-analytic methods using random effects model.