Time trends in ovarian cancer mortality in Europe (1955-1993): effect of age, birth cohort and period of death

Abstract

The time trend in ovarian cancer mortality in the European Union over the period 1955-1993, and the age, period-of-death and birth cohort components underlying the trend's evolution were analysed using log-linear Poisson models to quantify risk of dying from ovarian cancer in the different countries and regions of Europe, and ascertain the relative annual trend for each country. Furthermore, age-period-cohort models were fitted for each country in order to ascertain the effect on time trend exerted by the respective age, period-of-death and birth cohort components. Ovarian cancer mortality proved 2.77-fold (95% confidence interval (CI) 2.60-2.95) higher in northern versus southern Europe over the period 1955-1993. Denmark registered the highest adjusted rates, namely, 14.3 per 100000 person-years for the 1989-1993 5-year period, the last studied, with Portugal (4.5 per 100000) and Greece (4.5 per 100000) being the countries with the lowest rates. Spain and Greece, with annual rises of 5.8% (95% CI 5.3-6.3) and 5.1% (95% CI 4.2-6.0) respectively, were the countries that displayed the greatest increase in ovarian cancer mortality. Risk of death associated with the birth cohort effect declined in all northern countries from 1920 to 1930. In the south, Italy and France recorded a decline in risk from 1930. Women in Spain and Greece registered an increase in birth cohort-associated mortality, which became less pronounced after 1930. Ovarian cancer mortality in Europe evinces a south-north distribution pattern. The mortality risk for women cohorts born in northern Europe witnessed a gradual decline from 1920 to 1930. In the southern region: (1) Italy and France display a cohort effect of decreased risk from 1930; and (2) Greece and Spain show a cohort effect of increased risk among the different generations of women, though this became less pronounced from 1930 onwards.