Attending religious services at least once a week may offer spiritual and social protection against suicide, a large US study suggests.Among nearly 90,000 women followed for over a decade in the Nurses' Health Study, those with regular religious attendance had a five-fold lower risk of suicide compared to women who didn't go to services."There was also some evidence that this varied by religious affiliation: Protestant women who attended services once or more per week were approximately 3 times less likely to subsequently commit suicide, whereas Catholic women who attended services once or more per week were about 20 times less likely to commit suicide," lead author Tyler J. VanderWeele said by email."These are very large effect estimates," said VanderWeele, of the Harvard T.H. Chan School of Public Health in Boston.The researchers analyzed data on female nurses who were recruited starting in 1976 when they were 30 to 55 years old and who answered extensive lifestyle questionnaires every two years. Focusing on the period between 1996 and 2010, the study team followed 89,708 participants.Among women with a religious affiliation, most were Protestant or Catholic, and about 2,000 identified as Jewish, Buddhist, Hindu or "other."