Incident cardiovascular disease and particulate matter air pollution in South Korea using a population-based and nationwide cohort of 0.2 million adults

Table 1 Descriptive statistics of individual- and area-level characteristics of 196,167 subjects of the National Health Insurance Service-National Sample Cohort 2.0 in South Korea for 2007–2015

Characteristics		Total (n = 196,167)
Sex (%)	Male	53.5
Average age (years, mean ± SD)		46.6 ± 11.0
Age (years, %)	30–64	92.1
Income percentile ^a (%)	0–20%	11.8
	20–50%	24.6
	50–80%	36.9
	80–100%	26.7
Insurance type (%)	Self-employed	40.3
Insurance type (%)	Employee	59.7
Smoking status (%)	Never	67.7
	Former	9.2
	Current	23.1
Alcohol use (%)	≥ 3 times/week	10.3
Physical activity (%)	≥ 3 times/week	20.4
BMI (%)	≥ 25 kg/m²	33.4
Comorbidity (%)	Hypertension	21.0
	Diabetes	6.4
	Hyperlipidemia	12.0
Region (%)	Metropolitan cities	45.3
Region (%)	Provinces	54.7
Gross Regional Domestic Products^b (%)	Very low	8.0
	Low	17.7
	High	36.0
	Very High	38.3
Percent of the high school graduated or more^c (%)	Very low	9.9
	Low	15.9
	High	34.4
	Very High	39.9
Percent of the elderly^d (%)	Very low	37.6
	Low	35.9
	High	16.1
	Very High	10.3
Cardiovascular disease (n, incidence per 10³ person-year)	Total	33,580 (21.3)
	Ischemic heart disease	20,604 (13.1)
	Myocardial infarction	1367 (0.9)
	Stroke	10,201 (6.5)
	Heart Failure	3033 (1.9)

Abbreviations: SD standard deviation; BMI body mass index
^a NHIS-NSC provided income as percentiles (“The manual for User of the National Health Insurance Service of National Sample Cohort Database”)
^b Gross regional domestic products were categorized as very low (< 1110 M USD), low (1110–2600 M USD), high (2600–8354 M USD), and very high (≥ 8354 M USD) based on the distribution across approximately 250 districts
^c Percent of high school graduates was categorized as very low (< 34.3%), low (34.3–46.6%), high (46.6–53.2%), and very high (≥ 53.2%) based on the distribution across approximately 250 districts
^d Percent of the elderly aged 65 years or more was categorized as very low (< 5.4%), low (5.4–8.2%), high (8.2–14.9%), and very high (≥14.9%) based on the distribution across approximately 250 districts

ISSN: 1476-069X