Hukou	Chinese household registration system
NCMS	New Rural Cooperative Medical Insurance
URBMI	urban residents’ basic medical insurance system
URRBMI	urban and rural residents’ basic medical insurance system
CLDS	China Labor-Force Dynamic Survey
SAH	self-assessed of health status
CI	concentration index
ICC	Intra-Class Correlation Coefficient
M	mean value
SD	standard deviation
ID	interquartile distance