Gastric cancer in the European Union (1968-1992): mortality trends and cohort effect.

PURPOSE: To analyze patterns and trends in gastric cancer mortality in the European Union (EU) over the period 1968-1992, paying special attention to changes associated with birth cohort.
METHODS: Poisson log-linear models were used to quantify geographic differences and relative annual changes. To assess trends associated with birth cohort, invariant parameters from sex-specific age-period-chohort models (net drift and curvature), for each country, were used to choose a restricted slope range for cohort effect.
RESULTS: Gastric cancer mortality declined throughout the EU. The male-to-female ratio stood at around 2 in all countries, yet showed a slight rise over time. Portugal reported the highest age-adjusted rates for men and women (45.63 and 23.31 per 100,000 person-years, respectively). The rate ratio between two extreme countries (Portugal/Denmark) exceeded 3. Quantitative intercountry differences were found in trend slopes, with a decrease of 5% per annum in Finland. Risk of dying associated with birth cohort decreased over successive generations. Small local rises in risk, in almost all countries among generations born around the 1940s, support the importance of diet early in life in the etiology of gastric cancer.
CONCLUSIONS: Despite the substantial decline in gastric cancer mortality witnessed in the EU, stress must be accounted for the wide differences among countries and the smaller decline in the youngest generations, particularly among women. This latter finding suggests a possible stabilization or even a rise in the rates in future, rendering it important for these trends to be monitored over the next few years.