Design and baseline data of a population-based metabonomics study of eye diseases in eastern China: the Yueqing Ocular Diseases Investigation

Table 2 Comparing the characteristics of the participants with nonparticipants in the Yueqing Ocular Diseases Investigation

Characteristics	Participants		Non-participants		P value†
Characteristics	Number	Percentage	Number	Percentage	P value†
Gender					<0.001
Male	2175	45.6%	393	71.5%
Female	2594	54.4%	157	28.5%
Age (yrs)					<0.001
50–59	1884	39.5%	151	27.5%
60–69	1375	28.8%	203	36.9%
70–79	753	15.8%	113	20.5%
80–89	664	13.9%	55	10.0%
≥ 90	93	2.0%	28	5.1%
Median age (P25, P75)	62 (56, 74)		66 (58, 73)		P = 0.001
Marital status					P = 0.154
Married	4026	84.4%	468	85.1%
Unmarried	20	0.4%	4	0.7%
Widowed	709	14.9%	74	13.5%
Divorced	14	0.3%	4	0.7%
Educational background					<0.001
Illiteracy or semi-illiteracy‡	1419	29.8%	106	19.3%
Primary school (1–5 years)	2172	45.5%	259	47.1%
Middle school (6–8 years)	958	20.1%	139	25.3%
High school or above (9 years or above)	156	3.3%	36	6.5%
Unknown	64	1.3%	10	1.8%
History of diseases
History of hypertension	2390	50.1%
History of diabetes	479	10.0%
History of heart diseases	107	2.2%
History of stroke	51	1.1%
Sample collection
Serum and Plasma	1909	40.0%

†Chi-square test for categorical variables: gender, age groups, marital status, and educational background; Mann-Whitney U test for abnormal variables: age; and binary logistic regression analysis for the association of gender (P < 0.001), age (P = 0.004), educational background (P = 0.013) with a response to participate
‡“illiteracy” was defined as an inability to read any Chinese words; “semi-illiteracy” was defined as having some understanding of Chinese words, but obtained little to no useful information through reading

ISSN: 2326-0254