For both men and women, prophylactic daily aspirin use is associated with whether particular friends and family take aspirin or have had a recent cardiovascular event. This study adds to evidence that cardiovascular health behaviors spread through social networks.

Although the benefits of aspirin therapy are well-known, the rates of daily aspirin use are low. This study examined data from 2,724 adult children of participants in the Framingham Heart Study to determine whether these “egos” took aspirin daily, and whether usage was related to the aspirin usage or recent cardiovascular event (CVE) history of their friends and relatives (“alters”). Egos were limited to those most likely to be candidates for aspirin therapy, i.e., men, ages 45-79, and women, ages 55-70.

Key Findings:

• People were more likely to take aspirin if a friend or family member did so, but there were differences in the association by relationship (sibling, spouse, friend), gender, and gender composition of the relationship (e.g., brother and sister versus two brothers.)
• Overall, egos were 12 percent more likely to take aspirin if their alter recently took it, but there was no association between ego usage and an alter’s CVE history.
• Men were significantly more likely to use aspirin if their brother had recently had a CVE or a male friend used aspirin, but only slightly more likely if a male friend had had a CVE. There was no association between their recent aspirin usage and the CVE history of their sisters and wives.
• By comparison, women were significantly more likely to take aspirin if their brother recently did so, but there was only a slight association with the aspirin usage of their husbands, and none with the usage of their sisters or female friends. However, women were twice as likely to take aspirin daily if a female friend had recently suffered a CVE.

The study results add to the evidence that people’s health and health behaviors (including pharmacotherapy), are influenced by their social connections.

With funding from the Pioneer Portfolio, Nicholas Christakis is exploring how health outcomes and behaviors spread throughout a person’s social network.