Main features of studies included in this meta-analysis on the association between dietary intake (from food and/or supplements) of 25(OH)D and melanoma risk
| First author, Year | Study location | Sample size, n, T/C | % Male participants, T/C | Source of vitamin D | Reported estimate | Relative risk (95% CI) | Adjustment for covariates | Study quality (max. 9 points)* |
| Weinstock et al14 1992 | US | 165/209 | 44%/43% | Food+supplements | >9.9 versus<2.6 µg/day Yes versus no | 1.8 (0.9 to 3.5) 1.3 (0.8 to 2.2) | Age, family history of melanoma, hair colour | 7 |
| Millen et al15 2004 | US | 502/565 | 54%/57% | Food+supplements | ≥6.55 versus ≤1.58 µg /1000 kcal† | 0.66 (0.42 to 1.02) | Age, sex, study site | 9 |
| Asgari et al16 2009 | US | 68 611 | 48% | Food supplements | >7.1 versus ≤3.0 µg/day >9.9 versus none | 1.31 (0.94 to 1.82) 1.13 (0.89 to 1.43) | Age, gender, education | 8 |
| Vinceti et al17 2011 | Italy | 380/719 | 46.1%/44.4% | Food | ≥3.67 versus <1.62 µg/day | 0.53 (0.31 to 0.88) | Age, sex, province of residence, total energy, and calcium intake, phototype, skin sun reaction, history of sunburns, education | 9 |
| Tang et al18 2011 | US | 36 282 | 0 | Supplements | 10 µg/day versus none | 0.86 (0.64 to 1.16) | Age, sun exposure, anthropometry | 8 |
| Park et al19 2016 | US | 105 290 | 39.4% | Food supplements | ≥10 µg/day versus none † | 1.06 (0.96 to 1.39) 1.04 (0.87 to 1.26) | Family history of melanoma, hair colour, number of arm moles, sun exposure, body mass index, physical activity, smoking status, intakes of total energy, alcohol, coffee, and citrus intake | 8 |
*Study quality was judged based on the Newcastle-Ottawa Scale (1–9 stars).
†Reported as IU/day in the text and transformed into µg/day by using the equivalence: 1 µg=40 IU.
T/C, cases /controls.