Married Indian women who are physically or sexually abused by their husbands are four times more likely to become infected with HIV than women who are not abused, Reuters reports.

Researchers at the Harvard School of Public Health in Boston confirmed through earlier studies that men who have sex outside of marriage—including unprotected sex with sex workers—are the main source of HIV infection for India's women. This study, which examined data from India's National Family Health Survey between 2005 and 2006, found that HIV risk for women who suffered both physical and sexual abuse increased 3.9 times over those who suffered no abuse at all.

“A women who is abused by her husband is truly placed in a situation of ‘double jeopardy' regarding HIV infection,” said Jay Silverman, lead author of the study published in The Journal of the American Medical Association. “[The husband's] sexual behavior outside of the marriage makes it more likely he is infected with the virus, and his abusive behavior inside the marriage leaves her with little control over sex or sexual protection.”