Table 1.
Baseline characteristics of Koreans from 1998 to 2021, based on KNHANES data (N = 159,896), including both crude and weighted rates.
| Total | Pre-pandemic | During the pandemic | ||||||
|---|---|---|---|---|---|---|---|---|
| 1998–2021 | 1998–2005 | 2007–2009 | 2010–2012 | 2013–2015 | 2016–2019 | 2020 | 2021 | |
| Overall, n | 159,896 | 76,829 | 16,646 | 17,484 | 15,144 | 23,208 | 5331 | 5254 |
| Crude rate, n(%) | ||||||||
| Age (years), n(%) | ||||||||
| 20-39 | 57,064 (35.69) | 33,303 (43.35) | 5473 (32.88) | 5154 (29.48) | 4193 (27.69) | 6260 (26.97) | 1450 (27.20) | 1231 (23.43) |
| 40-59 | 59,378 (37.14) | 28,375 (36.93) | 6145 (36.92) | 6521 (37.30) | 5784 (38.19) | 8752 (37.71) | 1925 (36.11) | 1876 (35.71) |
| ≥60 | 43,454 (27.18) | 15,151 (19.72) | 5028 (30.21) | 5809 (33.22) | 5167 (34.12) | 8196 (35.32) | 1956 (36.69) | 2147 (40.86) |
| Sex, n(%) | ||||||||
| Men | 71,776 (44.89) | 36,071 (46.95) | 7054 (42.38) | 7414 (42.4) | 6381 (42.14) | 10,130 (43.65) | 2408 (45.17) | 2318 (44.12) |
| Women | 88,120 (55.11) | 40,758 (53.05) | 9592 (57.62) | 10,070 (57.60) | 8763 (57.86) | 13,078 (56.35) | 2923 (54.83) | 2936 (55.88) |
| Region of residence, n(%) | ||||||||
| Urban | 122,366 (76.53) | 56,893 (74.05) | 12,201 (73.30) | 13,820 (79.04) | 12,250 (80.89) | 18,850 (81.22) | 4266 (80.02) | 4086 (77.77) |
| Rural | 37,530 (23.47) | 19,936 (25.95) | 4445 (26.70) | 3664 (20.96) | 2894 (19.11) | 4358 (18.78) | 1065 (19.98) | 1168 (22.23) |
| BMI groupa, n(%) | ||||||||
| Underweight | 4389 (2.74) | 936 (1.22) | 751 (4.51) | 779 (4.46) | 637 (4.21) | 861 (3.71) | 199 (3.73) | 226 (4.30) |
| Normal weight | 40,314 (25.21) | 8221 (10.70) | 6543 (39.31) | 6993 (40.00) | 5965 (39.39) | 8896 (38.33) | 1845 (34.61) | 1851 (35.23) |
| Overweight | 23,959 (14.98) | 4619 (6.01) | 3970 (23.85) | 4072 (23.29) | 3578 (23.63) | 5313 (22.89) | 1205 (22.60) | 1202 (22.88) |
| Obese | 33,540 (20.98) | 5757 (7.49) | 5292 (31.79) | 5572 (31.87) | 4949 (32.68) | 8055 (34.70) | 2018 (37.85) | 1897 (36.11) |
| Unknown | 57,694 (36.08) | 57,296 (74.58) | 90 (0.54) | 68 (0.39) | 15 (0.10) | 83 (0.36) | 64 (1.20) | 78 (1.48) |
| Education, n(%) | ||||||||
| Elementary school or lower | 36,391 (22.76) | 18,697 (24.34) | 4524 (27.18) | 4159 (23.79) | 3217 (21.24) | 4138 (17.83) | 766 (14.37) | 890 (16.94) |
| Middle school | 18,870 (11.80) | 9566 (12.45) | 1980 (11.89) | 2037 (11.65) | 1741 (11.50) | 2457 (10.59) | 552 (10.35) | 537 (10.22) |
| High school | 50,443 (31.55) | 27,230 (35.44) | 4818 (28.94) | 4927 (28.18) | 4258 (28.12) | 6258 (26.96) | 1485 (27.86) | 1467 (27.92) |
| College or higher | 54,192 (33.89) | 21,336 (27.77) | 5324 (31.98) | 6361 (36.38) | 5928 (39.14) | 10,355 (44.62) | 2528 (47.42) | 2360 (44.92) |
| Household income, n(%) | ||||||||
| Lowest quartile | 33,377 (20.87) | 17038 (22.18) | 3565 (21.42) | 3435 (19.65) | 2944 (19.44) | 4456 (19.20) | 923 (17.31) | 1016 (19.34) |
| Second quartile | 39,557 (24.74) | 18855 (24.54) | 4161 (25.00) | 4509 (25.79) | 3829 (25.28) | 5705 (24.58) | 1254 (23.52) | 1244 (23.68) |
| Third quartile | 43,197 (27.02) | 20711 (26.96) | 4424 (26.58) | 4753 (27.18) | 4117 (27.19) | 6245 (26.91) | 1507 (28.27) | 1440 (27.41) |
| Highest quartile | 43,765 (27.37) | 20225 (26.32) | 4496 (27.01) | 4787 (27.38) | 4254 (28.09) | 6802 (29.31) | 1647 (30.89) | 1554 (29.58) |
| Perceived stress level, n(%) | ||||||||
| Greatly | 5411 (3.38) | 1540 (2.00) | 877 (5.27) | 750 (4.29) | 656 (4.33) | 1083 (4.67) | 264 (4.95) | 241 (4.59) |
| Quite a lot | 25,034 (15.66) | 6928 (9.02) | 3861 (23.19) | 3847 (22.00) | 3026 (19.98) | 5078 (21.88) | 1205 (22.60) | 1089 (20.73) |
| A little | 58,414 (36.53) | 11,552 (15.04) | 9011 (54.13) | 10,065 (57.57) | 8647 (57.10) | 13,089 (56.40) | 3041 (57.04) | 3009 (57.27) |
| Hardly at all | 17,813 (11.14) | 3858 (5.02) | 2875 (17.27) | 2787 (15.94) | 2659 (17.56) | 3904 (16.82) | 820 (15.38) | 910 (17.32) |
| Unknown | 53,224 (33.29) | 52,951 (68.92) | 22 (0.13) | 35 (0.20) | 156 (1.03) | 54 (0.23) | 1 (0.02) | 5 (0.10) |
| Weight change, n(%) | ||||||||
| No weight change | 66,081 (41.33) | 12,743 (16.59) | 10,915 (65.57) | 11,813 (67.56) | 9477 (62.58) | 14,753 (63.57) | 3235 (60.68) | 3145 (59.86) |
| Weight loss | 16,379 (10.24) | 4769 (6.21) | 2517 (15.12) | 2504 (14.32) | 2153 (14.22) | 2958 (12.75) | 730 (13.69) | 748 (14.24) |
| Weight gain | 24,176 (15.12) | 6347 (8.26) | 3186 (19.14) | 3127 (17.88) | 3358 (22.17) | 5440 (23.44) | 1366 (25.62) | 1352 (25.73) |
| Unknown | 53,260 (33.31) | 52,970 (68.95) | 28 (0.17) | 40 (0.23) | 156 (1.03) | 57 (0.25) | 0 (0.00) | 9 (0.17) |
| Occupation category, n(%) | ||||||||
| White collar job | 22,024 (13.77) | 3601 (4.69) | 3040 (18.26) | 3638 (20.81) | 3352 (22.13) | 5834 (25.14) | 1319 (24.74) | 1240 (23.60) |
| Blue collar job | 55,855 (34.93) | 24,833 (32.32) | 6683 (40.15) | 6698 (38.31) | 5507 (36.36) | 8307 (35.79) | 1899 (35.62) | 1928 (36.70) |
| Others | 55,674 (34.82) | 22,109 (28.78) | 6907 (41.49) | 7139 (40.83) | 6274 (41.43) | 9049 (38.99) | 2110 (39.58) | 2086 (39.70) |
| Unknown | 26,343 (16.48) | 26,286 (34.21) | 16 (0.10) | 9 (0.05) | 11 (0.07) | 18 (0.08) | 3 (0.06) | 0 (0.00) |
| Weighted rate (95 % CI) | ||||||||
| Age (years), weighted % (95 % CI) | ||||||||
| 20–39 | 39.37 (38.89–39.85) | 45.17 (44.41–45.94) | 41.94 (40.49–43.39) | 39.29 (37.94–40.65) | 37.08 (35.79–38.36) | 34.89 (33.76–36.02) | 34.30 (31.88–36.72) | 33.14 (30.87–35.41) |
| 40–59 | 39.36 (38.96–39.77) | 37.01 (36.36–37.65) | 39.32 (38.09–40.55) | 40.54 (39.46–41.62) | 40.87 (39.80–41.95) | 40.49 (39.53–41.45) | 40.16 (37.96–42.36) | 38.69 (36.90–40.48) |
| ≥60 | 21.27 (20.88–21.66) | 17.82 (17.27–18.36) | 18.74 (17.80–19.69) | 20.17 (19.17–21.16) | 22.05 (21.01–23.09) | 24.62 (23.56–25.68) | 25.54 (23.12–27.95) | 28.17 (25.76–30.58) |
| Sex, weighted % (95 % CI) | ||||||||
| Men | 49.14 (48.89–49.40) | 48.37 (48.07–48.68) | 49.55 (48.83–50.27) | 49.41 (48.66–50.16) | 48.78 (48.01–49.56) | 49.50 (48.86–50.15) | 50.21 (49.09–51.33) | 49.86 (48.53–51.18) |
| Women | 50.86 (50.60–51.11) | 51.63 (51.32–51.93) | 50.45 (49.73–51.17) | 50.59 (49.84–51.34) | 51.22 (50.44–51.99) | 50.50 (49.85–51.14) | 49.79 (48.67–50.91) | 50.14 (48.82–51.47) |
| Region of residence, weighted % (95 % CI) | ||||||||
| Urban | 82.27 (81.28–83.25) | 81.05 (80.27–81.83) | 80.57 (77.48–83.66) | 79.96 (76.70–83.23) | 82.89 (80.02–85.76) | 84.89 (82.46–87.32) | 84.89 (79.78–90.00) | 84.09 (79.07–89.11) |
| Rural | 17.73 (16.75–18.72) | 18.95 (18.17–19.73) | 19.43 (16.34–22.52) | 20.04 (16.77–23.30) | 17.11 (14.24–19.98) | 15.11 (12.68–17.54) | 15.11 (10.00–20.22) | 15.91 (10.89–20.93) |
| BMI groupa, weighted % (95 % CI) | ||||||||
| Underweight | 3.49 (3.36–3.63) | 1.04 (0.91–1.17) | 4.71 (4.29–5.14) | 4.73 (4.32–5.13) | 4.63 (4.21–5.05) | 3.94 (3.63–4.25) | 3.91 (3.20–4.61) | 4.33 (3.70–4.95) |
| Normal weight | 30.64 (30.23–31.04) | 9.06 (8.24–9.89) | 39.35 (38.46–40.24) | 39.71 (38.73–40.70) | 39.87 (38.95–40.79) | 38.26 (37.48–39.04) | 33.65 (32.06–35.23) | 35.81 (34.17–37.45) |
| Overweight | 18.17 (17.88–18.47) | 5.52 (5.00–6.04) | 23.61 (22.88–24.34) | 22.76 (21.98–23.54) | 23.01 (22.21–23.81) | 22.50 (21.86–23.14) | 22.94 (21.72–24.17) | 21.66 (20.25–23.08) |
| Obese | 26.63 (26.26–27.00) | 7.09 (6.43–7.75) | 31.81 (30.91–32.70) | 32.36 (31.40–33.33) | 32.39 (31.49–33.29) | 34.93 (34.13–35.74) | 38.50 (36.89–40.11) | 37.05 (35.23–38.86) |
| Unknown | 21.07 (20.45–21.70) | 77.29 (75.29–79.28) | 0.52 (0.36–0.68) | 0.44 (0.30–0.58) | 0.11 (0.04–0.17) | 0.36 (0.26–0.46) | 1.00 (0.71–1.30) | 1.16 (0.79–1.52) |
| Education, weighted % (95 % CI) | ||||||||
| Elementary school or lower | 16.04 (15.69–16.39) | 20.08 (19.43–20.73) | 18.56 (17.57–19.56) | 17.17 (16.17–18.17) | 14.94 (14.01–15.87) | 12.39 (11.62–13.16) | 9.48 (7.93–11.03) | 10.43 (8.77–12.09) |
| Middle school | 9.87 (9.64–10.09) | 11.3 (10.92–11.68) | 10.71 (10.09–11.34) | 10.35 (9.74–10.97) | 9.40 (8.82–9.98) | 8.60 (8.10–9.11) | 7.77 (6.70–8.83) | 7.56 (6.56–8.56) |
| High school | 31.13 (30.73–31.53) | 36.2 (35.52–36.87) | 31.39 (30.28–32.50) | 30.54 (29.43–31.66) | 29.20 (28.12–30.29) | 27.40 (26.51–28.30) | 28.71 (26.73–30.68) | 28.93 (27–30.87) |
| College or higher | 42.96 (42.38–43.55) | 32.42 (31.53–33.3) | 39.33 (37.77–40.89) | 41.93 (40.42–43.45) | 46.46 (44.95–47.96) | 51.6 (50.15–53.05) | 54.05 (50.75–57.35) | 53.08 (49.99–56.17) |
| Household income, weighted % (95 % CI) | ||||||||
| Lowest quartile | 16.85 (16.44–17.27) | 20.78 (19.95–21.61) | 16.26 (15.16–17.35) | 16.00 (14.97–17.03) | 15.28 (14.19–16.36) | 15.47 (14.53–16.41) | 13.81 (11.70–15.91) | 13.52 (11.53–15.51) |
| Second quartile | 24.80 (24.34–25.25) | 25.15 (24.41–25.89) | 25.09 (23.80–26.37) | 27.22 (25.89–28.54) | 24.63 (23.33–25.93) | 23.90 (22.89–24.90) | 21.73 (19.57–23.89) | 22.72 (20.59–24.85) |
| Third quartile | 28.62 (28.17–29.07) | 26.95 (26.24–27.66) | 28.78 (27.49–30.06) | 29.18 (27.97–30.39) | 29.55 (28.17–30.92) | 28.89 (27.88–29.91) | 29.86 (27.74–31.98) | 30.42 (28.21–32.64) |
| Highest quartile | 29.72 (29.09–30.35) | 27.12 (26.11–28.14) | 29.88 (28.06–31.70) | 27.60 (26.14–29.05) | 30.55 (28.80–32.30) | 31.74 (30.25–33.24) | 34.60 (31.11–38.09) | 33.34 (29.49–37.18) |
| Perceived stress level, weighted % (95 % CI) | ||||||||
| Hardly at all | 11.87 (11.61–12.13) | 4.63 (4.16–5.10) | 14.89 (14.13–15.65) | 13.32 (12.67–13.98) | 15.4 (14.69–16.12) | 14.71 (14.15–15.26) | 13.23 (11.98–14.48) | 15.2 (13.98–16.42) |
| A little | 46.10 (45.59–46.62) | 15.23 (13.86–16.61) | 55.66 (54.72–56.60) | 58.93 (58.03–59.83) | 57.55 (56.55–58.55) | 57.03 (56.25–57.82) | 57.58 (55.85–59.3) | 58.53 (57.03–60.03) |
| Quite a lot | 19.10 (18.74–19.45) | 8.59 (7.81–9.38) | 24.12 (23.36–24.88) | 23.10 (22.27–23.93) | 21.51 (20.68–22.33) | 23.20 (22.50–23.90) | 23.85 (22.13–25.57) | 21.7 (20.24–23.16) |
| Greatly | 4.05 (3.91–4.20) | 1.99 (1.75–2.23) | 5.21 (4.79–5.63) | 4.45 (4.10–4.81) | 4.61 (4.19–5.04) | 4.89 (4.55–5.22) | 5.33 (4.53–6.12) | 4.52 (3.85–5.18) |
| Unknown | 18.88 (18.11–19.65) | 69.55 (66.91–72.20) | 0.12 (0.06–0.19) | 0.19 (0.11–0.28) | 0.93 (0.73–1.13) | 0.18 (0.12–0.23) | 0.01 (0.00–0.04) | 0.05 (0.00–0.09) |
| Weight change, weighted % (95 % CI) | ||||||||
| No weight change | 49.53 (48.99–50.08) | 16.59 (15.12–18.05) | 63.22 (62.30–64.13) | 64.48 (63.45–65.50) | 60.32 (59.27–61.36) | 61.36 (60.51–62.20) | 58.12 (56.31–59.94) | 57.83 (56.03–59.63) |
| Weight loss | 11.72 (11.46–11.99) | 5.52 (4.99–6.06) | 14.94 (14.28–15.61) | 14.29 (13.58–15.00) | 14.52 (13.76–15.28) | 12.97 (12.44–13.50) | 13.93 (12.85–15.01) | 13.69 (12.55–14.82) |
| Weight gain | 19.85 (19.48–20.22) | 8.30 (7.52–9.09) | 21.70 (20.89–22.52) | 21.04 (20.15–21.94) | 24.24 (23.32–25.17) | 25.48 (24.73–26.23) | 27.95 (26.33–29.56) | 28.39 (26.80–29.97) |
| Unknown | 18.90 (18.13–19.67) | 69.59 (66.94–72.23) | 0.14 (0.07–0.20) | 0.19 (0.10–0.28) | 0.92 (0.72–1.12) | 0.20 (0.14–0.26) | NA | 0.09 (0.03–0.15) |
| Occupation category, weighted % (95 % CI) | ||||||||
| White collar job | 20.35 (19.95–20.75) | 5.43 (5.07–5.79) | 22.03 (20.99–23.06) | 23.68 (22.65–24.71) | 25.76 (24.68–26.84) | 28.64 (27.56–29.72) | 28.27 (25.90–30.64) | 27.28 (25.14–29.43) |
| Blue collar job | 35.54 (35.10–35.98) | 28.95 (28.37–29.53) | 39.46 (38.17–40.75) | 41.21 (39.93–42.50) | 37.11 (35.87–38.35) | 36.40 (35.33–37.46) | 35.38 (32.95–37.8) | 36.38 (34.19–38.57) |
| Others | 34.20 (33.82–34.58) | 28.91 (28.25–29.57) | 38.40 (37.34–39.46) | 35.05 (34.02–36.07) | 37.04 (36.03–38.05) | 34.88 (34.01–35.75) | 36.29 (34.34–38.23) | 36.34 (34.60–38.08) |
| Unknown | 9.91 (9.68–10.13) | 36.71 (36.12–37.30) | 0.12 (0.04–0.20) | 0.06 (0.00–0.11) | 0.09 (0.03–0.16) | 0.09 (0.04–0.13) | 0.07 (0.00–0.15) | NA |
Abbreviations: BMI, body mass index; CI, confidence interval; KNHANES, Korea National Health and Nutrition Examination Survey.
a
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 (23.0–24.9 kg/m2), and obese (≥25.0 kg/m2).