A family poses for a photo on a couch. They all smile.
Do siblings lower your cancer risk? New study finds people with big families are less likely to develop the disease. (For Spectrum Health Beat)

If you come from a large family, you may have a lower risk of cancer, a new study suggests.

Researchers analyzed data from 178 countries and found that people from larger families were less likely to get cancer than those from smaller families.

The link between family size and cancer risk was “independent of income, levels of urbanization and age,” study senior author Maciej Henneberg said in a University of Zurich news release. He’s a guest professor in the Institute of Evolutionary Medicine at the university, in Switzerland.

Family size included not just parents and their children, but also members of the extended family in the household.

This protective effect of a large family was stronger in men than in women, according to the study published recently in the journal BMC Cancer.

It’s important to note, however, that the study only found an association between family size and cancer risk. It did not prove a cause-and-effect connection.

Family life can be stressful, but can also provide positive emotional environments that can boost a person’s resistance to diseases, including cancer, the researchers said.

Family members supporting one another in following a healthy lifestyle may also provide protection against cancer, the study authors added.