A dose-response curve for sun exposure and basal cell carcinoma

Authors

  • Anne Kricker,

    Corresponding author
    1. International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372 Lyon Cedcx O8, France
    2. Cancer Epidemiology Research Unit, NSW Cancer Council, 153 Dowling St, Kings Cross NSW 2011
    • Cancer Epidemiology Research Unit. NSW Cancer Council. PO Box 572, Kings Cross NSW 2011. Australia. Fax: 61 2 368 08-43
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  • Bruce K. Armstrong,

    1. International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372 Lyon Cedcx O8, France
    2. Australiam Institute of Health and Welfare, GPO Box 570, Canberra, ACT 2601, Australia
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  • Dallas R. English,

    1. Departments of Public Health, University of Western Australia, Nedlands WA 6009, Australia
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  • Peter J. Heenan

    1. Pathology, University of Western Australia, Nedlands WA 6009, Australia
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Abstract

A population-based case-control study of sun exposure and basal cell carcinoma (BCC) was conducted in Western Australia in 1988. Its aim was to examine the relationship between risk of BCC and the amount and pattern of sun exposure. This report deals with amount of exposure. The odds ratios (ORs) for BCC on the head and neck and limbs decreased with increasing total exposure, whereas the opposite was observed for BCC on the less heavily exposed trunk, with the highest OR in those with the greatest exposure. In an analysis of all body sites together in which the total hours of exposure to the specific site was treated as a continuous variable, an initial rise in risk of BCC was seen with a peak OR of 1.4 at about 35,000 hr of exposure, followed by a fall. In contrast to these site-specific patterns, lifetime accumulated sun exposure of the whole body showed no appreciable association with BCC either in total or for working days only. Risk of BCC was positively associated with lifetime exposure on non-working days, however, with an OR for higher than baseline categories of around 1.7. There was a significant interaction between ability to tan and total and occupational sun exposure. Risk increased with increasing exposure in those who tanned well but not in those who tanned poorly. This pattern is consistent with other observations which indicate that beyond a certain level of sun exposure risk of BCC does not increase further.

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