Kidney cancer mortality in The Netherlands, 1950-94: prediction of a decreasing trend.

Background: Incidence and mortality rates of kidney cancer are known to be increasing world-wide. The reasons for these increases are not clear, but despite this it may still be possible to predict changes in the trend of occurrence.

Methods: Male and female kidney (plus ureter and urethra) cancer mortality per 10(5) person-years, from 1950 to 94, were calculated using national demographic and mortality data. Changes in the age structure of the Dutch population were adjusted using direct standardisation to the European standard population. The effects of age, calendar period and birth cohort on the temporal trend in mortality were evaluated using log-linear modelling.

Results: Male mortality from kidney cancer increased from three per 10(5) person-years in the 1950s to eight per 10(5) in the mid 1980s and remained relatively stable thereafter. Female mortality rates showed a comparable trend, from two per 10(5) in the 1950s to four per 10(5) in the 1980s. In addition to the effects of age, the temporal trend in males can be sufficiently explained as a birth cohort effect. Successive birth cohorts appear to have higher risks of dying from kidney cancer until the 1930 cohort. The younger birth cohorts appear to have lower risks. The trend in women is comparable to that in men but is less pronounced and shows only after excluding women under the age of 45.

Conclusion: The decreasing risk for generations born after 1930 will probably result in a decreasing trend in kidney cancer mortality in the near future. It is suggested that at least part of this changing trend in men (but not in women) is caused by the changing smoking behaviour of the Dutch population.