Further studies on skin melanomas apparently dependent on female sex hormones.

In the British Isles the incidence of mortality rates from malignant melanoma of the skin have been shown to be higher in females than in males in the later years of reproductive life. In populations with higher rates for malignant melanoma of skin (Scandinavia, Australasia etc), and also in Japan, where the rates are low, the ratio of female to male deaths is lower than in the British Isles. However, a similar pattern of age-specific sex ratios (risks for females compared with males peaking at some age in the latter half of reproductive life, and relatively low in middle age) is found in these populations. This 'gynaecologic' factor is not an artifact of interactions between age and year of birth effects, and appears to act multiplicatively with other aetiologic factors. These findings have implications for studies of the aetiology and pathogenesis of malignant melanoma, as well as for the descriptive mathematical modelling of the rates for purposes of environmental legislation.