Regional trends in Portuguese gastric cancer mortality (1984-1999).

The international decline in gastric cancer is mainly attributed to improved socio-economic conditions. However, some southern and eastern European countries showed slower and later decline, reflecting a less favourable general environment The same probably applies to regional differences within countries, making national indicators potentially misleading. Fitting log-linear Poisson models we compared trends in gastric cancer mortality (1984-1999) across 18 Portuguese regions. Pearson correlation coefficients were computed to assess the regional association between decline in cancer mortality and baseline cancer mortality and variation in indices of social development and medical care. National gastric cancer mortality changed -2.0% year in men and -2.2% year in women. The regional yearly variation in mortality ranged from -3.5% [95% confidence interval (CI) -4.5 to -2.5] to -0.6% (95% CI -1.4 to 0.2) in men, and from -3.7% (95% CI -4.8 to -2.7) to -0.8% (95% CI -1.6 to 0.0) in women. Regional variation was not significantly associated with baseline gastric cancer mortality (r = 0.18, P = 0.47), but with the variation in post-neonatal mortality (r = 0.59, P = 0.01). In Portugal, gastric cancer shows a wide regional variation in frequency trends. The correlation with known indicators of social and economic development indicates that future improvement in gastric cancer rates is expected in parallel with a more widespread development.