Influenza Vaccination and Cardiovascular Mortality in Women and Men at Least 60 Years of Age in the Metropolitan Area of São Paulo, Brazil

Abstract

Objectives: Influenza (flu) vaccination has been associated with a reduction in cardiovascular mortality in a metropolitan area of Brazil. Nevertheless, it is unknown whether sex influences this outcome. The aim of the study was analyze the cardiovascular disease (CVD) mortality in women and men before and after the initiation of a flu vaccination program. Methods: We analyzed the mortality of ischemic heart disease (IHD), stroke, and external causes (EC) in women and men at least 60 years of age in the metropolitan area of São Paulo before and after the initiation of a flu vaccination program. Estimates of the population were obtained from the Brazilian Institute of Geography and Statistics and the mortality data from the Ministry of Health for the period between 1980 and 2006. The risk of death was adjusted by the direct method using the 1960 world standard population. Results: Change in trend in mortality after vaccination was significant only for IHD (-9.3% vs -30.2%; P = .022) and remained unchanged for stroke (-31.4% vs -25.3%; P =.931) and EC (-8.5% vs -1.2%; P = .941). The decline in IHD pre- (1980-1995) and post-vaccination (1996-2006) was greater in women (-3.8% vs -28.8%; P = .001) than in men (-12.9% vs -30.4%; P = .054). Conclusion: Flu vaccination was associated with a significant reduction of IHD mortality, more so in women than in men.