Table 1. Baseline characteristics of Koreans in crude and weighted rates, based on data collected from the KNHANES between 1998 and 2021 (n=186,561)

Total 1998-2005 2007-2009 2010-2012 2013-2015 2016-2019 2020 2021
Overall, n 186,561 96,948 18,519 19,157 16,514 24,433 5,596 5,394
Crude rate (95% CI)
Age, years, (95% CI)
5-19 16.64 (16.47 to 16.80) 22.19 (21.93 to 22.45) 12.51 (12.03 to 12.98) 11.24 (10.80 to 11.69) 11.30 (10.82 to 11.78) 9.23 (8.87 to 9.60) 8.68 (7.95 to 9.42) 8.29 (7.55 to 9.02)
20-29 12.99 (12.83 to 13.14) 15.13 (14.90 to 15.35) 11.06 (10.61 to 11.51) 9.78 (9.36 to 10.20) 10.32 (9.85 to 10.78) 10.67 (10.28 to 11.06) 12.83 (11.95 to 13.71) 11.27 (10.43 to 12.12)
30-39 17.60 (17.43 to 17.78) 19.22 (18.98 to 19.47) 18.49 (17.94 to 19.05) 17.12 (16.59 to 17.66) 15.07 (14.53 to 15.62) 14.95 (14.50 to 15.40) 13.08 (12.20 to 13.96) 11.55 (10.70 to 12.40)
40-49 17.36 (17.19 to 17.53) 17.57 (17.33 to 17.81) 17.97 (17.42 to 18.52) 16.39 (15.86 to 16.91) 16.76 (16.19 to 17.33) 17.57 (17.10 to 18.05) 16.33 (15.36 to 17.30) 16.87 (15.87 to 17.87)
50-59 14.47 (14.31 to 14.63) 11.70 (11.50 to 11.90) 15.21 (14.69 to 15.73) 17.65 (17.11 to 18.19) 18.26 (17.67 to 18.85) 18.25 (17.76 to 18.73) 18.07 (17.06 to 19.07) 17.91 (16.89 to 18.93)
60-69 12.75 (12.60 to 12.90) 9.4 (9.29 to 9.66) 14.51 (14.00 to 15.02) 15.74 (15.22 to 16.25) 16.16 (15.60 to 16.72) 16.90 (16.43 to 17.37) 18.75 (17.72 to 19.77) 19.50 (18.45 to 20.56)
≥70 8.20 (8.08 to 8.33) 4.72 (4.59 to 4.85) 10.25 (9.81 to 10.69) 12.07 (11.61 to 12.54) 12.12 (11.63 to 12.62) 12.43 (12.02 to 12.84) 12.26 (11.40 to 13.12) 14.61 (13.67 to 15.55)
Sex, (95% CI)
Male 46.33 (46.10 to 46.55) 48.34 (48.02 to 48.65) 43.83 (43.11 to 44.54) 43.75 (43.05 to 44.45) 43.49 (42.73 to 44.25) 44.55 (43.93 to 45.18) 46.02 (44.71 to 47.32) 44.92 (43.59 to 46.25)
Female 53.67 (53.45 to 53.90) 51.66 (51.35 to 51.98) 56.17 (55.46 to 56.89) 56.25 (55.55 to 56.95) 56.51 (55.75 to 57.27) 55.45 (54.82 to 56.07) 53.99 (52.68 to 55.29) 55.08 (53.75 to 56.41)
Region of residence, (95% CI)
Urban 77.66 (77.48 to 77.85) 75.59 (75.32 to 75.86) 74.77 (74.14 to 75.39) 80.18 (79.62 to 80.75) 81.72 (81.14 to 82.31) 82.31 (81.84 to 82.79) 80.86 (79.83 to 81.89) 79.11 (78.02 to 80.19)
Rural 22.34 (22.15 to 22.52) 24.41 (24.14 to 24.68) 25.23 (24.61 to 25.86) 19.82 (19.25 to 20.38) 18.28 (17.69 to 18.86) 17.69 (17.21 to 18.16) 19.14 (18.11 to 20.17) 20.89 (19.81 to 21.98)
BMI* group, (95% CI)
Underweight (<18.5kg/m2) 4.57 (4.47 to 4.66) 3.09 (2.98 to 3.20) 7.14 (6.77 to 7.52) 6.69 (6.33 to 7.04) 6.08 (5.72 to 6.44) 5.42 (5.14 to 5.70) 5.24 (4.65 to 5.82) 5.47 (4.86 to 6.08)
Normal weight (18.5-22.9 kg/m2) 24.55 (24.35 to 24.74) 10.65 (10.46 to 10.85) 40.37 (39.67 to 41.08) 40.93 (40.23 to 41.63) 40.36 (39.61 to 41.11) 39.18 (38.57 to 39.80) 35.47 (34.22 to 36.73) 35.74 (34.46 to 37.02)
Overweight (23-24.9 kg/m2) 13.34 (13.18 to 13.49) 5.19 (5.05 to 5.33) 22.50 (21.90 to 23.10) 22.00 (21.42 to 22.59) 22.53 (21.90 to 23.17) 21.88 (21.36 to 22.40) 21.73 (20.65 to 22.81) 21.99 (20.88 to 23.09)
Obese (≥ 25.0 kg/m2) 18.52 (18.35 to 18.70) 6.31 (6.16 to 6.47) 29.53 (28.87 to 30.18) 30.01 (29.36 to 30.66) 30.94 (30.23 to 31.64) 33.27 (32.68 to 33.86) 36.74 (35.48 to 38.00) 35.65 (34.37 to 36.93)
Unknown 39.03 (38.81 to 39.25) 74.75 (74.48 to 75.03) 0.45 (0.36 to 0.55) 0.37 (0.28 to 0.46) 0.09 (0.04 to 0.14) 0.25 (0.19 to 0.31) 0.82 (0.59 to 1.06) 1.15 (0.87 to 1.43)
Education, (95% CI)
Elementary school or lower education 23.35 (23.16 to 23.55) 27.97 (27.69 to 28.26) 23.54 (22.93 to 24.15) 20.71 (20.14 to 21.29) 18.41 (17.82 to 19.01) 14.93 (14.48 to 15.37) 12.26 (11.40 to 13.12) 13.83 (12.91 to 14.75)
Middle school 14.72 (14.55 to 14.88) 14.94 (14.72 to 15.17) 16.10 (15.57 to 16.63) 15.36 (14.85 to 15.87) 14.59 (14.06 to 15.13) 13.26 (12.84 to 13.69) 12.79 (11.92 to 13.67) 12.57 (11.68 to 13.45)
High school 31.74 (31.53 to 31.95) 33.71 (33.41 to 34.01) 30.48 (29.82 to 31.15) 29.56 (28.91 to 30.21) 29.99 (29.29 to 30.69) 28.87 (28.30 to 29.43) 29.07 (27.88 to 30.26) 29.40 (28.19 to 30.62)
College or higher education 30.19 (29.99 to 30.40) 23.37 (23.11 to 23.64) 29.88 (29.22 to 30.54) 34.36 (33.69 to 35.04) 37.00 (36.26 to 37.74) 42.95 (42.33 to 43.57) 45.87 (44.57 to 47.18) 44.20 (42.87 to 45.52)
Smoking status, (95% CI)
Smoker 12.52 (12.37 to 12.67) 7.67 (7.51 to 7.84) 19.82 (19.25 to 20.40) 18.65 (18.10 to 19.20) 17.09 (16.51 to 17.66) 16.88 (16.41 to 17.35) 16.14 (15.17 to 17.10) 15.29 (14.33 to 16.26)
Ex-smoker 10.34 (10.20 to 10.48) 2.71 (2.61 to 2.81) 16.85 (16.31 to 17.39) 18.00 (17.45 to 18.54) 17.66 (17.08 to 18.24) 19.69 (19.20 to 20.19) 21.30 (20.23 to 22.37) 21.84 (20.74 to 22.94)
Non-smoker 37.83 (37.61 to 38.05) 15.19 (14.96 to 15.42) 57.00 (56.29 to 57.71) 63.35 (62.67 to 64.03) 65.25 (64.53 to 65.98) 63.43 (62.82 to 64.03) 62.56 (61.29 to 63.83) 62.87 (61.58 to 64.16)
Unknown 39.30 (39.08 to 39.52) 74.42 (74.15 to 74.70) 6.32 (5.97 to 6.67) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00)
Alcohol consumption, (95% CI)
Non-drinker 14.67 (14.51 to 14.83) 11.95 (11.74 to 12.15) 19.94 (19.36 to 20.51) 19.42 (18.86 to 19.98) 18.23 (17.64 to 18.82) 15.06 (14.61 to 15.51) 15.14 (14.20 to 16.07) 15.63 (14.66 to 16.60)
1–5 days/month 34.66 (34.45 to 34.88) 8.56 (8.39 to 8.74) 60.65 (59.95 to 61.35) 61.65 (60.97 to 62.34) 62.60 (61.86 to 63.34) 64.32 (63.72 to 64.92) 65.64 (64.39 to 66.88) 66.67 (65.41 to 67.92)
6-30days/month 11.98 (11.84 to 12.13) 5.06 (4.93 to 5.20) 19.37 (18.81 to 19.94) 18.93 (18.37 to 19.48) 19.17 (18.57 to 19.77) 20.62 (20.12 to 21.13) 19.23 (18.20 to 20.26) 17.70 (16.69 to 18.72)
Unknown 38.68 (38.46 to 38.90) 74.42 (74.15 to 74.70) 0.04 (0.01 to 0.07) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00)
Household Income, (95% CI)
Lowest quartile 19.03 (18.86 to 19.21) 20.55 (20.30 to 20.81) 19.48 (18.91 to 20.05) 17.86 (17.32 to 18.41) 17.19 (16.61 to 17.76) 16.49 (16.02 to 16.96) 14.76 (13.83 to 15.69) 16.02 (15.04 to 17.00)
Second quartile 25.09 (24.89 to 25.28) 25.09 (24.81 to 25.36) 24.86 (24.24 to 25.48) 25.83 (25.21 to 26.45) 25.65 (24.98 to 26.32) 24.86 (24.32 to 25.40) 23.86 (22.74 to 24.97) 23.82 (22.69 to 24.96)
Third quartile 27.90 (27.70 to 28.10) 27.68 (27.40 to 27.96) 27.60 (26.96 to 28.25) 27.98 (27.35 to 28.62) 28.30 (27.61 to 28.98) 28.03 (27.47 to 28.60) 29.63 (28.43 to 30.82) 28.92 (27.71 to 30.13)
Highest quartile 27.98 (27.77 to 28.18) 26.68 (26.40 to 26.96) 28.05 (27.41 to 28.70) 28.32 (27.69 to 28.96) 28.87 (28.18 to 29.56) 30.62 (30.04 to 31.20) 31.75 (30.54 to 32.97) 31.24 (30.00 to 32.48)
Weighted rate (95% CI)
Age (years), weighted % (95% CI)
5-19 14.16 (13.92 to 14.41) 21.29 (20.86 to 21.72) 12.87 (12.24 to 13.50) 12.71 (11.95 to 13.46) 11.85 (11.21 to 12.48) 9.78 (9.28 to 10.29) 9.01 (7.91 to 10.10) 8.54 (7.40 to 9.67)
20-29 16.17 (15.84 to 16.50) 16.43 (15.96 to 16.91) 17.11 (16.10 to 18.12) 16.11 (15.10 to 17.11) 15.88 (15.00 to 16.76) 15.67 (14.87 to 16.46) 15.90 (14.41 to 17.40) 15.57 (13.77 to 17.36)
30-39 18.39 (18.03 to 18.76) 19.76 (19.21 to 20.30) 20.09 (18.98 to 21.21) 18.85 (17.85 to 19.86) 17.54 (16.50 to 18.58) 16.77 (15.87 to 17.68) 16.17 (14.30 to 18.04) 15.80 (14.13 to 17.48)
40-49 18.98 (18.69 to 19.27) 18.42 (18.02 to 18.82) 20.21 (19.38 to 21.05) 19.64 (18.79 to 20.48) 18.95 (18.17 to 19.72) 18.93 (18.23 to 19.63) 18.42 (16.84 to 20.01) 18.14 (16.59 to 19.70)
50-59 15.58 (15.31 to 15.84) 11.22 (10.88 to 11.57) 14.66 (13.96 to 15.36) 16.44 (15.67 to 17.21) 17.90 (17.09 to 18.70) 18.72 (18.05 to 19.38) 19.13 (17.74 to 20.52) 18.48 (16.99 to 19.98)
60-69 10.41 (10.19 to 10.63) 8.46 (8.15 to 8.77) 9.18 (8.66 to 9.70) 9.58 (9.03 to 10.13) 10.62 (10.01 to 11.22) 12.43 (11.81 to 13.05) 14.13 (12.72 to 15.53) 15.22 (13.84 to 16.60)
≥70 6.31 (6.14 to 6.48) 4.42 (4.19 to 4.65) 5.88 (5.44 to 6.32) 6.68 (6.21 to 7.16) 7.28 (6.77 to 7.79) 7.70 (7.23 to 8.17) 7.25 (6.15 to 8.35) 8.26 (7.16 to 9.35)
Sex, weighted % (95% CI)
Male 49.97 (49.72 to 50.21) 49.61 (49.31 to 49.91) 50.32 (49.63 to 51.00) 50.19 (49.46 to 50.92) 49.49 (48.74 to 50.24) 50.13 (49.51 to 50.76) 50.71 (49.61 to 51.82) 50.50 (49.17 to 51.84)
Female 50.03 (49.79 to 50.28) 50.39 (50.09 to 50.69) 49.68 (49.00 to 50.37) 49.81 (49.08 to 50.54) 50.51 (49.76 to 51.26) 49.87 (49.24 to 50.49) 49.29 (48.18 to 50.39) 49.50 (48.16 to 50.83)
Region of residence, weighted % (95% CI)
Urban 83.05 (82.09 to 84.01) 82.40 (81.59 to 83.21) 81.26 (78.17 to 84.36) 80.70 (77.44 to 83.97) 83.37 (80.49 to 86.25) 85.55 (83.15 to 87.95) 85.45 (80.38 to 90.51) 84.88 (79.96 to 89.80)
Rural 16.95 (15.99 to 17.91) 17.60 (16.79 to 18.41) 18.74 (15.64 to 21.83) 19.30 (16.03 to 22.56) 16.63 (13.75 to 19.51) 14.45 (12.05 to 16.85) 14.55 (9.49 to 19.62) 15.12 (10.20 to 20.04)
BMI* group, weighted % (95% CI)
Underweight (<18.5kg/m2) 5.40 (5.22 to 5.57) 3.12 (2.80 to 3.44) 7.32 (6.81 to 7.83) 7.00 (6.55 to 7.46) 6.41 (5.92 to 6.90) 5.59 (5.22 to 5.96) 5.31 (4.50 to 6.11) 5.82 (4.89 to 6.75)
Normal weight (18.5-22.9 kg/m2) 30.74 (30.34 to 31.15) 9.23 (8.39 to 10.07) 40.49 (39.65 to 41.33) 41.08 (40.13 to 42.02) 41.01 (40.13 to 41.88) 39.33 (38.57 to 40.09) 34.91 (33.29 to 36.53) 36.27 (34.63 to 37.91)
Overweight (23-24.9 kg/m2) 16.71 (16.44 to 16.99) 4.85 (4.40 to 5.30) 22.22 (21.54 to 22.90) 21.34 (20.61 to 22.07) 21.93 (21.18 to 22.69) 21.46 (20.85 to 22.07) 21.91 (20.71 to 23.12) 20.84 (19.43 to 22.25)
Obese (≥ 25.0 kg/m2) 24.31 (23.97 to 24.65) 6.06 (5.50 to 6.63) 29.49 (28.66 to 30.31) 30.15 (29.27 to 31.04) 30.54 (29.68 to 31.40) 33.34 (32.55 to 34.14) 37.14 (35.52 to 38.76) 36.13 (34.34 to 37.91)
Unknown 22.84 (22.14 to 23.54) 76.73 (74.68 to 78.78) 0.48 (0.31 to 0.66) 0.42 (0.29 to 0.55) 0.12 (0.04 to 0.19) 0.28 (0.19 to 0.36) 0.73 (0.47 to 0.99) 0.95 (0.63 to 1.27)
Education, weighted % (95% CI)
Elementary school or lower education 16.05 (15.75 to 16.35) 24.51 (24.00 to 25.02) 16.12 (15.26 to 16.98) 14.75 (13.90 to 15.59) 12.94 (12.16 to 13.73) 10.37 (9.74 to 10.99) 8.13 (6.91 to 9.35) 8.79 (7.50 to 10.08)
Middle school 12.73 (12.52 to 12.95) 13.84 (13.50 to 14.17) 14.53 (13.89 to 15.18) 13.81 (13.21 to 14.40) 12.28 (11.71 to 12.86) 10.90 (10.40 to 11.40) 9.99 (8.92 to 11.07) 9.84 (8.82 to 10.85)
High school 32.05 (31.68 to 32.42) 34.03 (33.49 to 34.57) 33.05 (32.03 to 34.07) 32.39 (31.33 to 33.46) 31.22 (30.16 to 32.29) 29.74 (28.85 to 30.62) 30.18 (28.27 to 32.08) 30.25 (28.38 to 32.12)
College or higher education 39.17 (38.65 to 39.70) 27.63 (26.90 to 28.35) 36.29 (34.90 to 37.69) 39.05 (37.64 to 40.47) 43.55 (42.16 to 44.94) 49.00 (47.69 to 50.31) 51.70 (48.71 to 54.69) 51.12 (48.38 to 53.86)
Smoking status, weighted % (95% CI)
Smoker 17.17 (16.83 to 17.51) 7.35 (6.68 to 8.02) 24.02 (23.22 to 24.81) 23.76 (22.89 to 24.64) 20.66 (19.80 to 21.52) 19.80 (19.06 to 20.54) 18.32 (16.88 to 19.76) 17.45 (15.99 to 18.91)
Ex-smoker 14.24 (14.00 to 14.48) 3.16 (2.83 to 3.50) 17.33 (16.72 to 17.95) 17.44 (16.77 to 18.10) 17.68 (16.99 to 18.37) 19.86 (19.29 to 20.43) 22.12 (20.96 to 23.28) 22.89 (21.54 to 24.24)
Non-smoker 45.96 (45.42 to 46.51) 15.45 (14.10 to 16.79) 51.74 (50.72 to 52.77) 58.80 (57.91 to 59.69) 61.66 (60.78 to 62.54) 60.34 (59.59 to 61.09) 59.56 (57.97 to 61.15) 59.66 (57.85 to 61.48)
Unknown 22.63 (21.88 to 23.38) 74.05 (71.80 to 76.29) 6.91 (6.16 to 7.65) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00)
Alcohol consumption, weighted % (95% CI)
Non-drinker 14.29 (13.89 to 14.69) 12.88 (11.74 to 14.02) 16.92 (16.22 to 17.62) 16.38 (15.66 to 17.11) 15.50 (14.81 to 16.20) 13.05 (12.52 to 13.58) 12.70 (11.49 to 13.91) 13.06 (11.76 to 14.37)
1-5 days/month 47.77 (47.32 to 48.23) 8.97 (8.14 to 9.80) 61.89 (60.95 to 62.83) 62.36 (61.42 to 63.31) 63.55 (62.61 to 64.48) 65.05 (64.32 to 65.78) 66.35 (64.85 to 67.86) 67.99 (66.51 to 69.47)
6-30days/month 16.16 (15.88 to 16.44) 4.10 (3.69 to 4.51) 21.15 (20.37 to 21.94) 21.25 (20.48 to 22.02) 20.95 (20.14 to 21.75) 21.90 (21.26 to 22.53) 20.95 (19.58 to 22.32) 18.95 (17.61 to 20.29)
Unknown 21.78 (21.03 to 22.53) 74.05 (71.80 to 76.29) 0.04 (0.00 to 0.07) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00) 0.00 (0.00 to 0.00)
Income, weighted % (95% CI)
Lowest quartile 15.70 (15.29 to 16.10) 19.46 (18.65 to 20.28) 15.23 (14.15 to 16.30) 15.23 (14.17 to 16.30) 14.04 (13.00 to 15.07) 13.79 (12.91 to 14.67) 12.11 (10.14 to 14.07) 11.70 (9.90 to 13.50)
Second quartile 25.14 (24.67 to 25.61) 25.60 (24.83 to 26.38) 24.87 (23.57 to 26.18) 27.55 (26.16 to 28.93) 25.11 (23.75 to 26.47) 24.16 (23.11 to 25.21) 22.18 (19.88 to 24.47) 22.91 (20.64 to 25.17)
Third quartile 29.14 (28.67 to 29.60) 27.46 (26.73 to 28.19) 29.48 (28.16 to 30.80) 29.35 (28.09 to 30.61) 30.14 (28.73 to 31.55) 29.61 (28.55 to 30.68) 30.82 (28.59 to 33.06) 31.21 (28.95 to 33.48)
Highest quartile 30.03 (29.38 to 30.68) 27.47 (26.41 to 28.54) 30.42 (28.51 to 32.33) 27.87 (26.35 to 29.39) 30.71 (28.90 to 32.52) 32.44 (30.89 to 33.99) 34.89 (31.38 to 38.41) 34.18 (30.33 to 38.03)
Abbreviations: n, number; BMI, body mass index; CI, confidence interval; KNHANES, Korea National Health and Nutrition Examination Survey.
According to the Asian-Pacific guidelines, the BMI is divided into four groups: underweight (<18.5 kg/m2), normal (18.5-22.9 kg/m2), overweight (23–24.9 kg/m2), and obese (≥25 kg/m2).