Contrary to earlier reports, a new study finds that stress does not appear to increase a person's risk of developing multiple sclerosis (MS), according to a study published today in Neurology.

Researchers studied 2 groups of female nurses from the Nurses’ Health Study. The first study started in 1976 and followed 121,700 nurses between the ages of 30 and 55. The second study started in 1989 and followed 116,671 nurses between the ages of 25 and 42. Participants reported general stress at home and at work, including physical and sexual abuse in childhood and as teenagers. Of the first group, 77 people developed MS by 2005. In the second group, 292 people developed the disease by 2004.

"The risk of MS is particularly high among young women, and the difference in the number of cases is consistent with the different ages of women in the two groups at the beginning of the MS follow-up," said study author Trond Riise, PhD. 

After considering factors such as age, ethnicity, latitude of birth, body mass at age 18, and smoking, the study found that severe stress at home did not increase the risk of developing MS. There also was no significant increased risk in developing MS among those who reported severe physical or sexual abuse during childhood or adolescence.

"This rules out stress as a major risk factor for MS. Future research can now focus on repeated and more fine-tuned measures of stress," said Riise.