Sun exposure and melanoma risk at different latitudes: a pooled analysis of 5700 cases and 7216 controls.
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).


CONCLUSIONS
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.
Chang
Yu-mei
YM
Section of Epidemiology and Biostatistics, Leeds Institute of Molecular Medicine, Leeds, UK. y.chang@leeds.ac.uk
Barrett
Jennifer H
JH
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D Timothy
DT
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Bruce K
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Bataille
Veronique
V
Bergman
Wilma
W
Berwick
Marianne
M
Bracci
Paige M
PM
Elwood
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JM
Ernstoff
Marc S
MS
Gallagher
Richard P
RP
Green
Adèle C
AC
Gruis
Nelleke A
NA
Holly
Elizabeth A
EA
Ingvar
Christian
C
Kanetsky
Peter A
PA
Karagas
Margaret R
MR
Lee
Tim K
TK
Le Marchand
Loïc
L
Mackie
Rona M
RM
Olsson
Håkan
H
Østerlind
Anne
A
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Timothy R
TR
Sasieni
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P
Siskind
Victor
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Swerdlow
Anthony J
AJ
Titus-Ernstoff
Linda
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Michael S
MS
Newton-Bishop
Julia A
JA
D001499:Bayes Theorem; D016022:Case-Control Studies; D005260:Female; D005843:Geography; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007642:Keratosis / Q000453:epidemiology* / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000453:epidemiology* / Q000473:pathology; D016017:Odds Ratio; D010641:Phenotype; D012307:Risk Factors; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000473:pathology; D013472:Sunlight / Q000009:adverse effects*