Objective: To compare five alternative self-report methods for assessing the smoking status of Chinese urban residents, and to estimate their reliability or agreement.
Study design: Cross-sectional survey with multistage sampling.
Methods: Cross-sectional survey data were collected from residents in two Chinese cities, and the prevalence of smoking and smoking frequency were estimated by means of six methods of self-report labelled SMD, SM1, SM6, SMF, SMC and SM. SM, the method of smoking assessment endorsed by the World Health Organisation (WHO), served as a referent in estimating agreement among the domestic methods. Cohen's kappa measured overall intermethod agreement.
Results: Data on 1167 eligible respondents were analysed. kappa values ranged from 0.79 to 0.89 for current smoking, from 0.84 to 0.94 for daily smoking, and from 0.23 to 0.62 for occasional smoking. Compared with the referent (SM, 61%), SMD (53%), SM1 (57%), SM6 (54%) and SMC (55%) significantly understated the prevalence of current smoking among Chinese urban residents. SM1 (11%), SM6 (10%), SMD (6%) and SMC (6%) significantly understated the prevalence of occasional smoking compared with the refererent (SM, 14%). No variation emerged in prevalence estimates of daily smoking.
Conclusions: Despite some variability, the five domestic methods used to assess smoking status in China generally produced similar results to those based on SM, the method advocated by WHO. Discrepancies between domestic assessment methods peaked in estimating the prevalence of occasional smoking.
Copyright 2010 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.