G. Bentham et A. Aase, INCIDENCE OF MALIGNANT-MELANOMA OF THE SKIN IN NORWAY, 1955-1989 - ASSOCIATIONS WITH SOLAR ULTRAVIOLET-RADIATION, INCOME AND HOLIDAYS ABROAD, International journal of epidemiology, 25(6), 1996, pp. 1132-1138
Background. Norway has the highest incidence of melanoma in Europe. Th
is study analyses geographical variations in melanoma incidence within
Norway and their association with possible aetiological factors. Meth
ods. Data on melanoma incidence from the Norwegian Cancer Registry wer
e used to calculate standardized incidence ratios (SIR) for the 19 cou
nties in Norway for each 5-year period from 1955 to 1989. Multiple reg
ression analysis was used to examine the associations between these SI
R and local UVB levels, holidays abroad and income. Similar methods we
re also used to analyse changes in SIR between 1955-1969 and 1985-1989
. Results. There was a highly significant association between melanoma
incidence and UVB in each of the time periods studied. Income showed
a significant positive association in the 1960s and early 1970s but no
t later. Foreign holidays showed a significant positive association in
the 1980s, but not earlier. Changes in melanoma SIR between 1955-1969
and 1985-1989 were significantly positively associated with holidays
abroad and negatively with income levels. Conclusions. Melanoma incide
nce in Norway is closely related to local levels of UVB radiation inde
pendently of other factors suggesting that local exposures carry signi
ficant risk. Risks would probably increase if ozone depletion led to e
nhanced UVB flux (estimated as 1.6% rise in incidence for each 1% incr
ease in UVB). By the end of the study period income was no longer a si
gnificant factor but holidays abroad had started to have a detectable
effect on melanoma incidence.