This study collected a lot of health information from healthy women, through surveys and reviews of medical records, over a number of years. All of the women in this study were health professionals. This study focused on 122 women who developed heart attacks or strokes during the years of the study and 244 women who did not develop these problems. All of the women gave blood samples at the beginning of the study. The researchers tested these samples to look for antibodies to four kinds of bacteria and viruses.
Antibodies are substances that develop in the blood to help fight infection.
If a person has antibodies to a certain bacteria or virus in their blood, this means they had an infection with that germ some time in the past. The researchers compared whether the women who had heart attacks or strokes were more likely than those that did not to have antibodies suggesting past infections. Women with blood tests that suggested they had not had past infections were just as likely to develop heart disease or strokes as women whose blood tests suggested they did have previous infections. The study could not rule out very small increases in heart attacks or strokes. Also, the researchers looked at only four types of bacteria or viruses.