Limitations
The present study also has limitations. The predominance of women in the sample precluded the detection of possible gender differences in the results. Using self-report instruments to measure the primary outcome may also introduce bias into the results. Other major limitations include the limited sample size and the relatively high loss of participants during the follow-up period. Additionally, an NSA group with positive results indicates the need to investigate better the mechanisms of action and nonspecific outcomes associated with AA.