IJE Advance Access originally published online on April 8, 2009
International Journal of Epidemiology 2009 38(3):814-830; doi:10.1093/ije/dyp166
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Sun exposure and melanoma risk at different latitudes: a pooled analysis of 5700 cases and 7216 controls
1 Section of Epidemiology and Biostatistics, Leeds Institute of Molecular Medicine, Leeds, UK.
2 School of Public Health, The University of Sydney, Sydney, Australia.
3 Twin Research and Genetic Epidemiology Unit, St Thomas' Campus, Kings College London, London, UK.
4 Dermatology Department, West Herts NHS Trust, Hemel Hempstead General Hospital, Herts, UK.
5 Department of Dermatology, Leiden University Medical Center, Leiden, the Netherlands.
6 Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA.
7 Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
8 Cancer Control Research Program, British Columbia Cancer Agency, Vancouver, BC, Canada.
9 Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
10 Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Brisbane, Australia.
11 Department of Surgery, University Hospital, Lund, Sweden.
12 Department of Biostatistics and Epidemiology and Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA, USA.
13 Department of Community and Family Medicine, Dartmouth Medical School and the Norris Cotton Cancer Center, Lebanon, NH, USA.
14 Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI, USA.
15 Department of Public Health and Health Policy, Faculty of Medicine, University of Glasgow, UK.
16 Department of Oncology, University Hospital, Lund, Sweden.
17 Kobenhaausevej 25, DK 3400 Hillerød, Denmark.
18 Wolfson Institute of Preventive Medicine, Barts & The London School of Medicine, London, UK.
19 Section of Epidemiology, Institute of Cancer Research, Sir Richard Doll Building, Sutton, Surrey, UK.
20 Department of Community and Family Medicine and Department of Pediatrics, Dartmouth Medical School and the Norris Cotton Cancer Center, Lebanon, NH, USA.
* Corresponding author. Cancer Genetics Building, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK. E-mail: y.chang{at}leeds.ac.uk
| Abstract |
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Background Melanoma risk is related to sun exposure; we have investigated risk variation by tumour site and latitude.
Methods We performed a pooled analysis of 15 case–control studies (5700 melanoma cases and 7216 controls), correlating patterns of sun exposure, sunburn and solar keratoses (three studies) with melanoma risk. Pooled odds ratios (pORs) and 95% Bayesian confidence intervals (CIs) were estimated using Bayesian unconditional polytomous logistic random-coefficients models.
Results Recreational sun exposure was a risk factor for melanoma on the trunk (pOR = 1.7; 95% CI: 1.4–2.2) and limbs (pOR = 1.4; 95% CI: 1.1–1.7), but not head and neck (pOR = 1.1; 95% CI: 0.8–1.4), across latitudes. Occupational sun exposure was associated with risk of melanoma on the head and neck at low latitudes (pOR = 1.7; 95% CI: 1.0–3.0). Total sun exposure was associated with increased risk of melanoma on the limbs at low latitudes (pOR = 1.5; 95% CI: 1.0–2.2), but not at other body sites or other latitudes. The pORs for sunburn in childhood were 1.5 (95% CI: 1.3–1.7), 1.5 (95% CI: 1.3–1.7) and 1.4 (95% CI: 1.1–1.7) for melanoma on the trunk, limbs, and head and neck, respectively, showing little variation across latitudes. The presence of head and neck solar keratoses was associated with increased risk of melanoma on the head and neck (pOR = 4.0; 95% CI: 1.7–9.1) and limbs (pOR = 4.0; 95% CI: 1.9–8.4).
Conclusion Melanoma risk at different body sites is associated with different amounts and patterns of sun exposure. Recreational sun exposure and sunburn are strong predictors of melanoma at all latitudes, whereas measures of occupational and total sun exposure appear to predict melanoma predominately at low latitudes.
Keywords Melanoma, recreational sun exposure, occupational sun exposure, total sun exposure, sunburn, solar keratoses
Accepted 25 February 2009