Among older men in an ethnically and socioeconomically diverse California population, those who received pneumococcal vaccine did not have a lower risk of acute MI or stroke than did those who were unvaccinated.
Influenza vaccination has been shown to reduce the risk of MI, stroke, sudden cardiac death, cardiac hospitalization, and the need for revascularization, and similar results recently have been reported for vaccination against pneumococcus, said Hung Fu Tseng, Ph.D., of Kaiser Permanente Southern California, Pasadena, and his associates.
It is thought that respiratory infections can trigger an exaggerated inflammatory response that causes destabilization of atherosclerotic plaques and activation of the coagulation cascade.
To explore the possible protective effect of pneumococcal vaccine against MI and stroke, Dr. Tseng and his colleagues reviewed data from 84,170 men enrolled in the Kaiser health plan who were 45–69 years of age at baseline in 2000 and were followed through 2007.
There were 2,705 incident acute MIs and 1,134 incident strokes.
The rate of MI was 10.7 per 1,000 person-years in men who received at least one pneumococcal vaccination, compared with 6.1 per 1,000 person-years in men who had not received any pneumococcal vaccinations. The rate of stroke was 5.3 per 1,000 person-years in vaccinated men and 1.9 per 1,000 person-year in unvaccinated men.
“We found no evidence for an association between pneumococcal vaccine and reduced risk of acute MI or stroke” in the general study population. Moreover, there also was no protective effect in important subgroups such as smokers, men with diabetes, men with hypertension, and men with low cardiovascular risk (JAMA 2010;303:1699-706).
These results contrast with a well-publicized recent case-control study. Dr. Tseng's study was different in that it controlled for subjects' dietary habits, disease history, and lifestyle factors such as smoking and level of physical activity.
This study was funded by California Cancer Research Program and Kaiser Permanente. Dr. Tseng and his associates reported ties to Merck, the developer of a pneumococcal vaccine, and GlaxoSmithKline.
The MI rate was 10.7/1,000 person-years with vaccination and 6.1 without.
Source ©Pamela Moore/iStockphoto.com