Malignant melanoma. A controlled study of possibly associated factors

126

Summary. The incidence of, and mortality from, malignant melanoma of skin in whites are strongly influenced by socio-economic conditions. Professional and administrative workers have the highest rates of all. Clerks and salesmen have higher rates than skilled manual workers, who have higher rates than unskilled workers.Women, when classified by the occupation of their husbands, show a similar relationship to social status.The biases of incidence data from systems of cancer registration, and mortality data from death certificates are different, and the consistency of the data from different periods and from different populations suggests that the relationship is real.The bulk of the data is from Britain, but there is sufficient from the U.S. to indicate that the effect is not restricted to one country.No consistent increase in risk was found in outdoor workers compared with indoor workers of similar socio-economic status.

Section: Discussionmentioning

confidence: 99%

Malignant melanoma: social status and outdoor work

Lee¹,

Strickland²

1980

126

“…It has been demonstrated from inter-racial comparisons that dark pigmentation protects against melanoma (Oettle, 1966;Crombie, 1979). There have also been reports that even among so-called whites those with very fair complexions are more susceptible to melanoma induction (Lancaster & Nelson, 1957;Gellin et al, 1969). Within Europe there is a marked contrast in skin colour between the olive-complexioned, darkhaired Mediterraneans in the south, and the fair-skinned, blond-haired Scandinavians.…”

Section: Discussionmentioning

confidence: 99%

Variation of melanoma incidence with latitude in North America and Europe

Crombie¹

1979

107

Summary.-The relationship between melanoma incidence and latitude was investigated in North America and Europe, using the data collected by 43 population-based cancer registries. In North America melanoma incidence increased with decreasing latitude, supporting the role of UV light in the induction of melanoma. Within England the data from the National Cancer Registration scheme also showed the trend of increased frequency of melanoma with decreasing latitude. In contrast, across Europe the trend was in the opposite direction, of increasing melanoma incidence with increasing latitude. It is suggested that across Europe there is a range of skin colour from dark in the south to light in the north, which gives rise to a range of susceptibility to the induction of melanoma by UV. The effect of this susceptibility must be large enough to overwhelm the opposing effect of decreased UV intensity at higher latitudes, and this emphasizes the dangers of excessive solar exposure to fair-skinned individuals. The population of England may be a sufficiently random mix of skin colour, owing to repeated invasions, for the effect of UV intensity to be observed.

“…Melanin granules may exert a protective effect by absorbing UV, thereby preventing damage to the DNA of the melanocytes. Thus there is an increased susceptibility to melanoma among the more fair-skinned of Caucasians (Lancaster & Nelson, 1957;Gellin et al, 1969), particularly among those of Celtic descent (Miyaji, 1963). In contrast there have been several reports of a low incidence of melanoma among darkskinned races living in tropical latitudes (Oettle, 1966;Camain et al, 1972;Miyaji, 1963).…”

mentioning

confidence: 99%

Racial differences in melanoma incidence

Crombie¹

1979

113

Summary.-The incidences of malignant melanoma recorded by 59 populationbased cancer registries were investigated to determine the effects of racial and skincolour differences. White populations exhibited a wide range of melanoma incidences and females commonly, though not invariably, had a higher incidence than males. Non-white populations experienced in general a much lower incidence of melanoma although there was some overlap of white and non-white rates. No predominant sex difference emerged among non-whites.Populations of African descent were found to have a higher incidence than those of Asiatic origin, but it was concluded that this was due largely to the high frequency of tumours among Africans on the sole of the foot. A clear negative correlation between degree of skin pigmentation and melanoma incidence emerged for the exposed body sites. These data provide strong support for the hypotheses that UV radiation is a major cause of malignant melanoma and that melanin pigmentation protects against it. Further research is required to elucidate the aetiology of melanoma of the sole of the foot.