A well-known study in 1979 found that people who socialize with others live longer than people who keep to themselves. A new study shows that socializing online may have health benefits as well.

　　To test the theory, researchers from Harvard, Yale, Northeastern and the University of California at San Diego looked at the Facebook profiles of 12 million people. Then they compared the profiles with the California Department of Public Health records over a two-year period from 2011 to 2013.

　　The researchers found that that people with more friends online were less likely to die than similar people who were not as connected.

　　The researchers published their findings in an article titled "Online social integration is associated with reduced mortality risk" in the Proceedings of the National Academy of Sciences.

　　Findings of the Study

　　Not all Facebook usage was connected to a longer life. Getting friend requests related to reduced mortality, but sending friend requests did not.

　　Similarly, posting photos and being tagged in photos was connected to living longer, but sending messages on Facebook was not. People who were tagged in many photos had the lowest mortality rates in the study.

　　Some diseases had a significant reduction of mortality with Facebook users. Deaths from infections, diabetes, mental illness or dementia, heart disease, stroke, other cardiovascular diseases, liver disease, and homicide all were significantly lower for Facebook users than for non-users.

　　Other causes of death did not show a relation to Facebook usage, including sexually transmitted diseases, several types of cancer, unintentional injuries, drug overdoses, and suicides.

　　Limitations of the Study

　　The study did not examine any other social media sites to see if using them prolonged life. Also, two of the researchers worked at Facebook while the study was being conducted.

　　William Hobbes, one of the researchers who was a postdoctorate fellow at Northeastern University, and co-author of the study, worked at Facebook as a research intern in 2013.

　　Hobbes said that Facebook agreed not to interfere with the research, no matter what the result was. But, he added, researchers "were pretty confident that we were going to find this result."

　　The researchers were careful to say that their results showed an associative relationship between using Facebook and living longer, not a causal one. In other words, researchers did not prove that using Facebook makes someone live longer. The study simply showed a connection between a longer life and some activities users do on Facebook.

　　The researchers say the findings may be able to help show how online social networks can help improve people's health on a global scale.