Effect of FAB on health related quality of life in the combined subsample, with propensity score techniques to control the confounding factors in 20% of the total respondents, a cross sectional study in five cities, china, 2007–2008 (n = 3,179).

Role emotional refers to role limitations due to emotional problems; Role physical, refers to role limitations due to physical problems;
*P<0.05, **P<0.01, ***P<0.001;
aThe brief self-administered questionnaire SF-36 was used to measure health related quality of life. Item scores for each SF-36 domains were coded, summed and transformed to a scale from 0 (worst possible health state) to 100 (best possible health state).