Multivariable analysis (standardised to the census population of China 2010).

a.Ref.: reference group.b.Sampling method: if the study included all the older people in the specific geographical areas, it was considered as “place” type of sampling unit. If the final sampling unit of the study was each individual, it was categorised as “people” type.c.Socioeconomic level of area: based on economic development information (average household income) and political status (municipality, city and county) of the provinces or areas in China Statistical Yearbook 2010 [10]. For Hong Kong and Taiwan, the two nationwide studies were separated as two categories and dropped because of collinearity.d.Diagnostic criteria: DSM-III/–IV: Diagnostic and Statistical Manual of Mental Disorder Third/Fourth Edition; ICD-9/10: the International Statistical Classification of Diseases 9th/10th; CCMD: Chinese Classification of Mental Disease; Mixed: multiple diagnostic criteria including DSM, ICD or CCMD.