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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

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

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
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
Provinces 54.7
Gross Regional Domestic Productsb (%) Very low 8.0
Low 17.7
High 36.0
Very High 38.3
Percent of the high school graduated or morec (%) Very low 9.9
Low 15.9
High 34.4
Very High 39.9
Percent of the elderlyd (%) 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)
  1. Abbreviations: SD standard deviation; BMI body mass index
  2. a NHIS-NSC provided income as percentiles (“The manual for User of the National Health Insurance Service of National Sample Cohort Database”)
  3. 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
  4. 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
  5. 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