Secular Trends in the Mortality by Cerebrovascular Diseases in Portugal: 1902-2012

Abstract

Introduction: Cerebrovascular diseases (CVD) are one of the main causes of death in Portugal. Research on the epi- demiologic history might help to understand the phenomenon and guide intervention strategies. Objectives: (1) Describe historic trends in mortality. (2) Estimate the impact of demographic variations on the registered number of cases.

Methods: (1) We calculated rates, specific and standard- ized, for deaths registered as CVD (ICD-10: I60-I69, G45; ICD- 8/9: 430-438; ICD-6/7: 330-334) by sex (1902-2012) and by sex and age groups (1913-2012). We used Join point analysis to identify statistically significant changes in standardized death rates, and multivariate regression models, Poisson and negative binomial, controlling for demographic dynamics and time trend, from 1913 to 2012. (2) We calculated the contribution of demographic variations using the application RiskDiff. (3) We evaluated if changes in coding rules might have been a source of bias. Data source: National Institute of Statistics.

Results: (1) We gathered the longest and most discriminated mortality series from CVD in Portugal with data since the beginning of nationwide collection. Mortality increases exponentially with age and is higher in men. (2) We observed sig- nificant variations in age-standardized time trends (1913-1933: APC 2.0%; 1933-1955: APC -0.9%; 1955-1974: 2.9%; 1974- 1996: -2.4%; 1996-2012: -6.5%). (3) Population ageing exerted a significant pressure to increase the number of deaths, particularly in the second half of the twentieth century. However, this effect was counterweighted by protective factors.

Conclusion: CVD mortality in Portugal is particularly expressive when compared to other European countries, although significant gains have been observed in the last decades. Population ageing combined with a transition between the morbid and mortality dimensions changed the public health paradigm.