Pneumococcal vaccination and risk of acute myocardial infarction and stroke in men.

BACKGROUND

Multiple studies have shown that preventing influenza by vaccination reduces the risk of vascular events. However, the effect of pneumococcal polysaccharide vaccine on vascular events remains controversial.

OBJECTIVE

To examine the association between pneumococcal vaccination and risk of acute myocardial infarction (MI) and stroke among men.

METHODS

A prospective cohort study of Kaiser Permanente Northern and Southern California health plans with 84 170 participants aged 45 to 69 years from the California Men's Health Study who were recruited between January 2002 and December 2003, and followed up until December 31, 2007. The cohort was similar to the population of health plan members and men who responded to a general health survey in California on important demographic and clinical characteristics. Demographic and detailed lifestyle characteristics were collected from surveys. Vaccination records were obtained from the Kaiser Immunization Tracking System.

METHODS

Incidence of acute MI and stroke during the follow-up period in men who had no history of such conditions.

RESULTS

During follow-up, there were 1211 first MIs in 112,837 vaccinated person-years (10.73 per 1000 person-years) compared with 1494 first MI events in 246,170 unvaccinated person-years (6.07 per 1000 person-years). For stroke, there were 651 events in 122,821 vaccinated person-years (5.30 per 1000 person-years) compared with 483 events in 254,541 unvaccinated person-years (1.90 per 1000 person-years). With propensity score adjustment, we found no evidence for an association between pneumococcal vaccination and reduced risk of acute MI (adjusted hazard ratio [HR], 1.09; 95% confidence interval [CI], 0.98-1.21) or stroke (adjusted HR, 1.14; 95% CI, 1.00-1.31). An inverse association was also not found in men of different age and risk groups. The results appeared to be consistent, because using more specific International Classification of Diseases, Ninth Revision codes for the outcome definition did not change the estimations.

CONCLUSIONS

Among a cohort of men aged 45 years or older, receipt of pneumococcal vaccine was not associated with subsequent reduced risk of acute MI and stroke.