Table 2.
Description of the two‐level estimates extracted for each study (described exactly as reported in the articles)
| First author (Publ. year) | Estimate reported in the publication | Aggregated1 two‐level estimate | Effect measure | Minimally adjusted estimate (95% CI) | Adjustment of minimally adjusted estimate2 | Maximally adjusted estimate (95% CI) | Adjustment of maximally adjusted estimate2 |
|---|---|---|---|---|---|---|---|
| Hospital‐based case–control studies | |||||||
| Klepp (1979)22 | Use of any kind of sun lotion/oil during solar irradiation: almost never ‐ very rarely ‐ sometimes ‐ quite often ‐ always | Use of any kind of sun lotion/oil during solar irradiation: almost never ‐ ever | OR | 2.05 (1.06–4.03) | None | nr | |
| Graham (1985)23 | Use of sun screening lotion: no ‐ yes | Use of sun screening lotion: no ‐ yes | OR | 2.20 (1.20–4.10) | Age | nr | |
| Ródenas (1996)31 | Sunscreen use: never ‐ sometimes ‐ always | Sunscreen use: never ‐ ever | OR | 0.38 (0.20–0.70) | None | 0.43 (0.21–0.90) | Age, skin colour, skin type, recreational sun exposure, occupational sun exposure, nevi |
| Wolf (1998)33 | Use of sunscreens: never ‐ rarely ‐ often | Use of sunscreens: never ‐ ever | OR | 1.74 (1.18–2.57) | Age, sex | 2.15 (1.37–3.37) | Age, sex, skin colour, sunbaths, sunburns |
| Espinosa A. (1999)34 | Use of sunscreens: no ‐ yes | Use of sunscreens: no ‐ yes | OR | 0.38 (0.28–0.63)3 | None | 0.45 (0.33–0.67)3 | Skin type, freckles, age |
| Naldi (2000)35 | Sunscreen use: never ‐ sometimes ‐ often | Sunscreen use: never ‐ ever | OR | 1.14 (0.89–1.45) | None | 0.90 (0.68–1.18) | Age, sex, demographic area, education, skin colour, eye colour, hair colour, freckles, nevi, sunburns, tanning pattern, sunny holiday weeks per year |
| Bakos (2002)37 | Sunscreen use habit: never ‐ SPF <8, SPF 8–15, SPF 15+ | Sunscreen use habit: never ‐ ever (all SPF) | OR | 0.46 (0.29–0.74)3 | None | 0.34 (0.18–0.63)3 | Eye colour, hair colour, photo‐ type, freckles, nevi, dysplastic nevi, physical protection, sunburn |
| Nikolaou (2008)64 | Sunscreen use: never/rarely ‐ during summer/sunny months | Sunscreen use: never/rarely ‐ during summer/sunny months | OR | 0.56 (0.34–0.90) | Conditional regression | 0.37 (0.14–0.98) | Age, gender, phototype, skin colour, outdoor leisure activities, weeks/year of sun exposure, sunburns <20 years of age, common nevi, atypical nevi, lentigenes |
| Klug (2010)39 | Sunscreen use: no use ‐ ever use | Sunscreen use: no use ‐ ever use | OR | 1.05 (0.82–1.35) | Matched logistic regression analysis | 0.90 (0.70–1.19) | Gender, age, study site, Ethnic group, ambient resident UV, hours outdoors, tan type, sunburns, gender, age group, study site |
| Luiz (2012)63 | Lifetime sunscreen use: never/almost never ‐ occasionally ‐ modified ‐ often | Lifetime sunscreen use: never/almost never ‐ ever | OR | 0.53 (0.22–1.24) | Age, sex, education | 0.34 (0.11–1.01) | Age, sex, education, ethnicity, eye colour, history of pigmented lesion removal, sunburns age 5–19, severe lifetime sunburns |
| Vranova (2012)65 | Use of the sunscreen in the adulthood: never ‐ occasionally ‐ regularly | Use of the sunscreen in the adulthood: never ‐ ever | OR | 0.63 (0.36–1.12)4 | None | 0.19 (0.09–0.43)4 | Freckles/nevi, sunburns in childhood, sunscreen in childhood, sunbathing in adulthood, sun exposure, time of day of sun exposure, holidays at seaside, holidays in mountains, solarium use |
| Population‐based case–control studies | |||||||
| Holman (1986)24 | Use of sunscreens: never ‐ <10 years ‐ ≥10 years | Use of sunscreens: never ‐ ever | OR | nr | 1.11 (0.82–1.49) | Age, sex, electoral subdivision, chronic and acute skin reaction to sunlight, hair colour, ethnic origin, age at arrival in Australia | |
| Østerlind (1988)25 | Use of sunscreens: never ‐ <10 years ‐ ≥10 years | Use of sunscreens: never ‐ ever | OR | 1.23 (0.98–1.55)4 | None | nr | |
| Beitner (1990)26 | Employment of sun protection agents: never ‐ rarely ‐ often/very often | Employment of sun protection agents: never ‐ ever | OR | nr | 1.59 (1.17–2.15)3 | Age, sex, hair colour | |
| Herzfeld (1993)27 | Using sunscreens: no ‐ yes | Using sunscreens: no ‐ yes | OR | 0.81 (0.58–1.12) | None | nr | |
| Autier (1995)28 | Regular sunscreen use: never ‐ ever | Regular sunscreen use: never ‐ ever | OR | 1.59 (1.18–2.14) | Conditional regression | 1.50 (1.09–2.06) | Age, sex, hair colour, holiday weeks in sunny resorts, municipality |
| Holly (1995)29 | Use of sunscreen 5 years before diagnosis: never ‐ sometimes ‐ almost always | Use of sunscreen 5 years before diagnosis: never ‐ ever | OR | 0.67 (0.51–0.87)4 | None | 0.52 (0.37–0.73) | Sunburns ≤12 years, skin reaction to sun, hair colour, nevi, complexion, maternal ethnicity, history of skin cancer, age |
| Westerdahl (1995)30 | Use of sunscreens: never ‐ sometimes ‐ almost always | Use of sunscreens: never ‐ ever | OR | 1.65 (1.24–2.20) | Matched analysis | 1.47 (1.08–2.01) | Sunburns, sunbathing in summer, outdoor employment in summer, nevi, hair colour, eye colour, freckling, age, gender, parish |
| Whiteman5 (1997)32 | Sunscreen use at school: never/rarely ‐ sometimes ‐ often ‐ always | Sunscreen use at school: never/rarely ‐ ever | OR | 1.73 (0.97–3.08) | Matched analysis | 1.01 (0.50–2.05) | Tanning ability, freckling, nevi, sex, school, grade |
| Westerdahl (2000)36 | Use of sunscreens: never ‐ sometimes ‐ always initially of the year then sometimes ‐ always | Use of sunscreens: never ‐ ever | OR | 1.35 (1.08–1.69) | Conditional regression | 1.30 (0.90–1.90) | Hair colour, sunburns, sunbathing in summer, duration of sunbathing, age, sex, parish |
| Youl6 (2002)38 | Average lifetime index of sunscreen use at home: never/rarely ‐ sometimes ‐ often/always | Average lifetime index of sunscreen use at home: never/rarely – ever | OR | 1.05 (0.63–1.74) | Conditional regression | nr | |
| Lazovich (2011)40 | Routine sunscreen use: nonusers in both decades ‐ middle ‐ high in both decades | Routine sunscreen use: nonusers in both decades ‐ users in both decades | OR | 1.33 (0.91–1.95) | Age, gender | 1.12 (0.78–1.62) | Age, gender, phenotype risk score, moles, income, education, family history, sunburns, sun exposure, solarium use |
| Savoye (2018)66 | Sunscreen use since age 25: no protection ‐ SPF <8 ‐ SPF 8–15 ‐ SPF >15 | Sunscreen use since age 25: no protection ‐ SPF <8/SPF 8‐15/SPF >15 | OR | 1.71 (1.29–2.27) | Conditional regression | 1.50 (1.10–2.06) | Skin sensitivity, nevi, freckling, eye colour, skin colour, hair colour, hours of recreational sun exposure, recreational UV score, sunburns >25 years, age, birth county, education |
| Prospective ecological study | |||||||
| Kojo (2006)67 | Rate ratio for CM per 1 euro increase per capita in sunscreen sales | Rate ratio per 1 euro increase per capita in sunscreen sales | RR | nr | 0.48 (0.35–0.66) | Age, gender, 10 year lag time, sunny resort holidays, holiday duration | |
| Prospective cohort studies | |||||||
| Cho7 (2005)68 | Percent of time of sunscreen use when outside at the pool or beach in the past summer: 0–25 ‐ 50 ‐ 75 ‐ 100 | Percent of time sunscreen used outside at the pool or beach in past summer: 0 ‐ ≥25 | HR | 1.66 (1.41–1.96) | Age | 1.42 (1.21–1.68) | Age, alcohol consumption, sunburns, childhood reaction to sun, hair colour, smoking, BMI, exercise, UV flux, moles, caffeine, family history of CM |
| Ghiasvand (2016)69 | Sunscreen use from time‐dependent analysis: never ‐ ever | Sunscreen use from time‐dependent analysis: never ‐ ever | HR | 1.45 (1.11–1.90) | Age, calendar year | 1.13 (0.85–1.50) | Age, calendar year, hair colour, freckles, ambient UV, weeks sunbathing, sunburns, solarium use |
| Stenehjem8 (2017)70 | Present sunscreen use: never/rarely ‐ often ‐ almost always | Present sunscreen use: never/rarely ‐ often/almost always | HR | 1.11 (0.69–1.76) | Age | 1.10 (0.77–1.57) | Age, benzene exposure, education |
| Randomised controlled trial | |||||||
| Green (2011)21 | Random assignment to daily or discretionary sunscreen application to head and arms | Sunscreen application to head and arms: daily ‐ discretionary | HR | 0.50 (0.24–1.02) | 0.49 (0.24–1.02) | Sex, skin type, nevi, history of cancer, sun exposure | |
Abbreviations: BMI, body mass index; CI, confidence interval; CM, cutaneous melanoma; HR, hazard ratio; nr, not reported; OR, odds ratio; Publ., publication; SPF, sun protection factor; RR, rate ratio; RCT, randomised controlled trial; UV, ultraviolet.
1
If sunscreen exposure was reported in more than two categories they were aggregated into two categories (ever‐ vs. never‐use).
2
As reported by the authors.
3
Estimate from individual‐matched case–control study that did not take the matching into account in the statistical analysis, or did not report it.
4
Estimate from frequency‐matched case–control study that did not adjust for the matching variables in the statistical analysis, or did not report it.
5
Sunscreen and melanoma in childhood.
6
Sunscreen and melanoma in adolescence.
7
Estimates received upon author request because they were not reported in the cited article.
8
Case‐cohort study design.