Table 1

Definition of variables and description for adults in China 1997–2011

Variables	1997		2000		2004		2006		2009		2011
Variables	N	%	N	%	N	%	N	%	N	%	N	%
LNINCOME, mean (SE)	8.07	0.01	8.24	0.01	8.51	0.01	8.62	0.01	9.01	0.01	9.25	0.01
Gender
Female*	4256	51.42	4798	52.21	4653	52.32	4581	52.76	4857	52.61	6555	53.06
Male	4021	48.58	4392	47.79	4240	47.68	4102	47.24	4375	47.39	5799	46.94
Urban
Rural*	5700	68.5	6311	68.33	6173	68.91	6025	68.89	6400	68.88	7182	57.69
Urban	2621	31.5	2925	31.67	2785	31.09	2721	31.11	2892	31.12	5268	42.31
Health insurance
No*	6053	73.47	6996	77.54	6455	72.41	4355	49.79	832	8.95	612	4.92
Yes	2186	26.53	2027	22.46	2459	27.59	4391	50.21	8460	91.05	11 838	95.08
Education attainment
Illiteracy*	2335	28.97	2061	23.1	1885	21.09	2152	24.67	2112	22.76	2455	19.75
Primary school	1808	22.43	1991	22.31	2070	23.16	1569	17.99	1801	19.41	2029	16.32
Middle school	2354	29.21	2832	31.73	2801	31.33	2671	30.62	3084	33.23	3847	30.95
High school	1030	12.78	1205	13.5	1238	13.85	1223	14.02	1101	11.86	1640	13.19
College and above	532	6.6	835	9.36	945	10.57	1107	12.69	1183	12.75	2458	19.78
Marriage
Single*	1142	13.84	1078	12.12	777	8.72	615	7.04	586	6.31	687	5.52
Married	6527	79.08	7182	80.72	7357	82.57	7328	83.89	7782	83.78	10 475	84.18
Else	585	7.09	637	7.16	776	8.71	792	9.07	921	9.91	1282	10.3
Age group
18–30*	2100	25.24	1868	20.23	1261	14.08	1014	11.59	1072	11.54	1374	11.04
31–45	2811	33.78	3152	34.13	2782	31.06	2729	31.2	2663	28.66	3207	25.76
46–60	2041	24.53	2614	28.3	3011	33.61	2983	34.11	3228	34.74	4516	36.27
>60	1369	16.45	1602	17.35	1904	21.25	2020	23.1	2329	25.06	3353	26.93
Smoke
No*	5603	67.73	6277	68.52	6057	67.74	6001	68.67	6388	68.77	8638	69.4
Yes	2670	32.27	2884	31.48	2884	32.26	2738	31.33	2901	31.23	3808	30.6
Drink
No*	5202	63.53	5819	64.73	6007	67.19	5946	67.99	6229	67.06	8227	66.09
Yes	2986	36.47	3171	35.27	2933	32.81	2799	32.01	3060	32.94	4221	33.91
Tea consumption, mean (SE)	0.62	0.01	0.67	0.01	0.64	0.01	1.91	0.02	2.13	0.02	2.24	0.01
Activity
No*	7435	89.35	8438	91.36	8216	91.72	7964	91.06	8546	91.97	10 692	85.88
Yes	886	10.65	798	8.64	742	8.28	782	8.94	746	8.03	1758	14.12
Area
East*	1120	15.28	1132	13.69	1059	13.24	982	12.75	1144	13.84	3426	30.01
Middle	3832	52.28	4967	60.06	4769	59.62	4561	59.23	5007	60.57	4840	42.4
West	2378	32.44	2171	26.25	2171	27.14	2158	28.02	2116	25.6	3150	27.59

LNINCOME means natural logarithm of per capital household income; tea consumption means the average of water and tea consumption per day, and LNINCOME and tea consumption are considered as continue variables. Dummy variables were generated for category variables in regression models.
*Reference levels; mean and SE were calculated for continuous variables and observations (N) and percentage (%) was used for category variables.