Basal cell and squamous cell carcinomas

For both BCC and SCC, exposure-response functions were obtained from unpublished data derived from a previous study (Lucas et al. 2006).   This used ambient erythemally weighted UVR as the exposure metric to develop exposure-disease relationships for SCC and BCC as follows:

1. spreadsheets were developed (Microsoft Excel) to record data on incidence rates by sex and age group (recording all data by geographical position of the study region and year of publication for studies from 1979 to 2003; 
2. using these data, population-level exposure-response curves (annual ambient erythemal UVR vs. incidence rate) were constructed for each WHO age group, for lightly pigmented populations.

ERFs were available for males and females and for the following age groups: 0-4, 5-14, 15-29, 30-44, 45-59, 60-69, 70-79, 80+.  The relationships are not linear.

Estimates of mortality rates were estimated using incidence-mortality ratios (Lucas et al. 2006).  Results were combined with the population estimates in order to estimate skin cancer incidence (rates) and mortality (rates).  Attributable incidence and mortality were calculated using the upper and lower estimates of population attributable fractions (PAF) as estimated by the WHO (Lucas et al. 2006) (Table 1).

Exposure-response function used for malignant melanoma (CMM)

For mealignant melanoma, ERFS were derived using estimates of the biological amplification factor (BAF) presented by Scotto and Fears (1987).  This represents the relative change in disease risk (incidence in this case) due to a 10% increase in UVR exposure. The estimates are adjusted for age, and are based on US data; non-whites have been excluded as they are less likely to develop melanoma skin cancer. The ERF is linear. 

Scotto and Fears (1987) make a distinction between melanoma on different locations: face, head or neck (FHN) and upper extremity (UE), and the trunk & lower extremity (TL) (Table 2). Here, the data were applied as an indication of the change in disease risk of a decrease in UV exposure. The FHN/UE result is considered as the higher risk estimate and the TL result as the lower estimate.

Mortality rates were estimated using age-specific incidence-mortality ratios, based on the incidence and mortality rates in the EURA region, as presented by Lucas et al (2006).  The results were combined with the population data to provide an estimate of skin cancer incidence (rates) and mortality (rates). Attributable incidence/mortality were calculated using the upper (0.9) and lower (0.5) estimates of population attributable fractions (PAF) as estimated by the WHO (Lucas 2006).