Table 2.

Baseline Descriptive Characteristics of the CLHLS Study Sample

		Residence
Variables	Total (n = 17,333)	Urban (n = 2325)	Rural to Urban (n = 5059)	Rural (n = 9578)	Urban to Rural (n = 371)	P value
Demographic characteristics
Age, mean (SD)	77.9 (7.87)	77.3 (8.10)	78.3 (7.80)	77.5 (7.94)	77.8 (7.84)	<0.001
Male,%	51.40	51.74	49.99	82.05	52.02	0.122
Han ethnicity,%	93.69	96.00	95.77	91.98	94.88	<0.001
Socioeconomic Factors
Education,%
No education	52.28	31.14	49.38	59.11	47.98	<0.001
6 years of education	34.41	35.27	35.93	33.44	33.15
7+ years of education	13.31	33.59	14.69	7.44	18.87
Prof./admin. Occupation,%	10.62	25.55	15.81	4.20	11.86	<0.001
Economic independence,%	39.96	68.00	48.73	28.43	42.32	<0.001
Childhood SES, mean (SD)	1.73 (0.77)	1.80 (0.85)	1.72 (0.78)	1.73 (0.74)	1.86 (0.76)	<0.001
Family Support Factors
Married,%	50.22	53.68	49.26	49.79	52.56	0.002
High proximity to children,%	83.29	70.67	77.98	89.13	83.83	<0.001
Behavioral Factors
Current smoking,%	24.09	21.29	21.82	26.02	22.64	<0.001
Exercises regularly,%	34.86	55.61	46.67	23.07	48.25	<0.001
Consumes vegetables,%	89.35	91.57	90.16	88.36	90.16	<0.001
Consumes fish,%	30.65	41.20	35.11	25.42	38.54	<0.001
Health Status
Any chronic condition,%	60.53	69.25	64.18	56.59	57.95	<0.001
Any ADL disability,%	12.10	15.14	15.04	9.95	8.63	<0.001
Any IADL disability,%	49.91	46.62	50.56	50.29	51.75	0.007
MMSE, mean (SD)	25.7 (5.93)	26.85 (5.09)	25.87 (5.90)	25.26 (6.10)	26.30 (5.68)	<0.001
Died during study period,%	41.12	32.56	44.57	41.12	47.71	<0.001 <0.001
Loss to follow-up,%	28.60	45.42	35.86	19.25	33.42

Abbreviations: SD standard deviation