Table 1.

Baseline characteristics of the three study groups

Variables	HAS(N = 504)	KNHANES(N = 10,152)	OAI(N = 4796)	P-value
Age (years), means ± SD	70.1 ± 7.9	64.3 ± 9.5	61.1 ± 9.1	< 0.0001
Female	54.3	56.9	58.5	0.0774
Diabetes	10.1	14.6	7.7	< 0.0001
CVA	6.3	3.4	2.9	0.0003
MI	4.5	5.1	1.9	< 0.0001
Hyperlipidemia	5.7	16.3	NA	< 0.0001
Osteoporosis	19.2	12.3	12.1	< 0.0001
BMI (kg/m2), means ± SD	24.6 ± 3.2	23.9 ± 3.1	28.6 ± 4.8	< 0.0001
Smoker	40.4	40.5	47.1	< 0.0001
Alcohol	41.4	77.5	80.3	< 0.0001
Low education	77.9	65.2	70.9	< 0.0001
Low income	45.9	75.2	75.7	< 0.0001
Marriage	68.8	77.7	66.8	< 0.0001
KL grade 4 in any tibio-femoral joint	9.3	7.6	11.5	< 0.0001

All data are presented as percentages unless otherwise specified. Low education level was defined as < 9 years of education in HAS and KNHANES, and as less than high school graduation in OAI. Low income was defined as the lowest quartile of yearly household income in HAS and KNHANES and as yearly household income lower than $100,000 USD in OAI. Continuous variables showing normal distribution (BMI) were tested using ANOVA. Age was tested using Kruskal Wallis test and categorical variables using chi-square test

HAS Hallym Aging Study, KNHANES Korean National Health and Nutrition Examination Survey, OAI Osteoarthritis Initiative, SD Standard deviation, CVA Cerebrovascular accident, MI Myocardial infarction, KL grade Kellgren–Lawrence grade