Table 3. Weighted odds ratio of before and during the pandemic, OR (95% CI), in the data obtained from the KNHANES

	1998–2005 (reference) versus 2007-2009	P-value	2007-2009 (reference) versus 2010-2012	P-value	2010-2012 (reference) versus 2013-2015	P-value	2013-2015 (reference) versus 2016-2019	P-value	2016-2019 (reference) versus 2020	P-value	2020 (reference) versus 2021	P-value
Overall
Preschool (2-5 years)	2.87 (1.88 to 4.37)	<.0001	1.31 (0.87 to 1.98)	0.189	0.51 (0.31 to 0.82)	0.005	0.62 (0.35 to 1.11)	0.105	0.27 (0.07 to 0.97)	0.045	0.55 (0.05 to 5.62)	0.614
School age (6-18 years)	4.70 (3.48 to 6.35)	<.0001	1.19 (0.94 to 1.50)	0.159	0.90 (0.68 to 1.18)	0.438	0.72 (0.54 to 0.95)	0.021	0.82 (0.51 to 1.33)	0.420	1.10 (0.57 to 2.13)	0.774
Adults (19-39 years)	2.88 (2.17 to 3.83)	<.0001	1.47 (1.09 to 1.98)	0.012	1.08 (0.82 to 1.44)	0.579	1.14 (0.88 to 1.47)	0.334	1.13 (0.78 to 1.62)	0.527	0.86 (0.53 to 1.37)	0.516
Adults (40-59 years)	1.59 (1.27 to 1.99)	<.0001	0.98 (0.74 to 1.31)	0.912	0.84 (0.62 to 1.14)	0.252	0.92 (0.70 to 1.22)	0.569	0.99 (0.63 to 1.55)	0.947	1.18 (0.69 to 2.02)	0.543
Older population (≥60 years)	1.07 (0.90 to 1.27)	0.426	0.90 (0.74 to 1.10)	0.316	0.86 (0.69 to 1.06)	0.154	0.92 (0.75 to 1.13)	0.410	0.88 (0.66 to 1.17)	0.368	1.20 (0.84 to 1.72)	0.321
Male
Preschool (2-5 years)	3.12 (1.89 to 5.15)	<.0001	1.24 (0.76 to 2.03)	0.394	0.51 (0.29 to 0.90)	0.020	0.69 (0.35 to 1.33)	0.266	0.34 (0.09 to 1.27)	0.109	NA	NA
School age (6-18 years)	4.84 (3.32 to 7.05)	<.0001	1.24 (0.93 to 1.65)	0.149	0.80 (0.58 to 1.11)	0.187	0.70 (0.50 to 0.99)	0.043	1.09 (0.64 to 1.86)	0.740	1.15 (0.53 to 2.49)	0.721
Adults (19-39 years)	2.44 (1.58 to 3.76)	<.0001	1.84 (1.18 to 2.88)	0.007	0.92 (0.61 to 1.38)	0.670	1.35 (0.94 to 1.94)	0.106	1.13 (0.72 to 1.78)	0.602	0.70 (0.36 to 1.33)	0.273
Adults (40-59 years)	1.39 (0.99 to 1.96)	0.058	0.87 (0.55 to 1.39)	0.563	0.99 (0.59 to 1.65)	0.960	0.71 (0.44 to 1.15)	0.166	1.40 (0.70 to 2.81)	0.342	1.12 (0.48 to 2.60)	0.793
Older population (≥60 years)	0.82 (0.62 to 1.07)	0.135	0.96 (0.70 to 1.32)	0.800	0.59 (0.42 to 0.84)	0.004	1.36 (0.95 to 1.93)	0.090	0.86 (0.53 to 1.40)	0.538	0.84 (0.43 to 1.62)	0.595
Female
Preschool (2-5 years)	2.43 (1.14 to 5.19)	0.021	1.53 (0.76 to 3.06)	0.232	0.49 (0.22 to 1.10)	0.082	0.48 (0.18 to 1.25)	0.130	NA	NA	NA	NA
School age (6-18 years)	4.52 (2.82 to 7.26)	<.0001	1.10 (0.76 to 1.59)	0.632	1.08 (0.72 to 1.62)	0.704	0.74 (0.50 to 1.11)	0.149	0.47 (0.20 to 1.10)	0.082	0.98 (0.32 to 3.05)	0.971
Adults (19-39 years)	3.44 (2.35 to 5.03)	<.0001	1.13 (0.75 to 1.68)	0.562	1.34 (0.91 to 1.96)	0.137	0.91 (0.64 to 1.30)	0.599	1.12 (0.63 to 2.00)	0.696	1.11 (0.56 to 2.19)	0.767
Adults (40-59 years)	1.76 (1.30 to 2.38)	0.000	1.06 (0.74 to 1.50)	0.758	0.75 (0.52 to 1.08)	0.117	1.09 (0.79 to 1.52)	0.602	0.78 (0.43 to 1.42)	0.414	1.24 (0.59 to 2.58)	0.569
Older population (≥60 years)	1.29 (1.03 to 1.60)	0.025	0.87 (0.67 to 1.13)	0.290	1.02 (0.78 to 1.33)	0.895	0.77 (0.60 to 0.98)	0.034	0.89 (0.63 to 1.26)	0.515	1.44 (0.94 to 2.21)	0.095
Urban
Preschool (2-5 years)	2.59 (1.66 to 4.06)	<.0001	1.37 (0.87 to 2.14)	0.171	0.46 (0.27 to 0.80)	0.006	0.59 (0.30 to 1.15)	0.118	0.36 (0.09 to 1.34)	0.125	0.54 (0.05 to 5.55)	0.606
School age (6-18 years)	4.49 (3.27 to 6.15)	<.0001	1.23 (0.96 to 1.58)	0.104	0.73 (0.54 to 0.99)	0.043	0.76 (0.55 to 1.04)	0.088	0.71 (0.40 to 1.25)	0.236	1.38 (0.65 to 2.92)	0.406
Adults (19-39 years)	3.12 (2.30 to 4.22)	<.0001	1.45 (1.06 to 1.99)	0.021	1.09 (0.81 to 1.48)	0.571	1.01 (0.77 to 1.33)	0.942	1.19 (0.80 to 1.76)	0.385	0.89 (0.54 to 1.47)	0.642
Adults (40-59 years)	1.35 (1.04 to 1.76)	0.024	1.15 (0.83 to 1.60)	0.396	0.77 (0.55 to 1.08)	0.132	0.93 (0.69 to 1.27)	0.663	1.05 (0.65 to 1.70)	0.857	1.19 (0.66 to 2.13)	0.568
Older population (≥60 years)	1.13 (0.90 to 1.42)	0.279	0.98 (0.77 to 1.27)	0.901	0.79 (0.61 to 1.03)	0.079	0.94 (0.74 to 1.20)	0.625	0.85 (0.61 to 1.18)	0.329	1.19 (0.78 to 1.83)	0.416
Rural
Preschool (2-5 years)	5.48 (1.56 to 19.30)	0.008	1.09 (0.41 to 2.87)	0.864	0.73 (0.27 to 1.95)	0.526	0.83 (0.27 to 2.55)	0.747	NA	NA	NA	NA
School age (6-18 years)	9.02 (3.44 to 23.64)	<.0001	0.93 (0.46 to 1.85)	0.829	2.48 (1.24 to 4.97)	0.011	0.63 (0.34 to 1.18)	0.148	1.55 (0.72 to 3.30)	0.261	0.37 (0.13 to 1.06)	0.064
Adults (19-39 years)	1.50 (0.68 to 3.29)	0.313	1.67 (0.71 to 3.92)	0.243	1.03 (0.44 to 2.38)	0.955	2.76 (1.31 to 5.80)	0.008	0.78 (0.29 to 2.10)	0.619	0.54 (0.15 to 1.92)	0.337
Adults (40-59 years)	2.73 (1.71 to 4.37)	<.0001	0.59 (0.32 to 1.11)	0.100	1.18 (0.57 to 2.43)	0.658	0.91 (0.48 to 1.70)	0.759	0.72 (0.21 to 2.40)	0.589	1.16 (0.29 to 4.68)	0.830
Older population (≥60 years)	0.99 (0.77 to 1.26)	0.902	0.74 (0.54 to 1.01)	0.057	1.04 (0.72 to 1.48)	0.847	0.85 (0.60 to 1.19)	0.333	0.99 (0.58 to 1.69)	0.980	1.21 (0.62 to 2.35)	0.580
Education (high school or lower education)
Preschool (2-5 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
School age (6-18 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
Adults (19-39 years)	2.88 (1.83 to 4.53)	<.0001	1.51 (0.89 to 2.55)	0.129	1.22 (0.69 to 2.15)	0.497	0.94 (0.54 to 1.66)	0.837	1.86 (0.87 to 4.00)	0.110	0.42 (0.16 to 1.09)	0.074
Adults (40-59 years)	1.54 (1.21 to 1.96)	<.0001	1.06 (0.77 to 1.45)	0.733	0.77 (0.53 to 1.12)	0.178	0.88 (0.61 to 1.26)	0.488	1.08 (0.54 to 2.16)	0.835	0.68 (0.28 to 1.67)	0.401
Older population (≥60 years)	1.13 (0.95 to 1.34)	0.178	0.90 (0.73 to 1.10)	0.305	0.94 (0.76 to 1.17)	0.601	0.86 (0.70 to 1.06)	0.163	1.09 (0.81 to 1.45)	0.585	1.03 (0.73 to 1.47)	0.861
Education (college or higher education)
Preschool (2-5 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
School age (6-18 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
Adults (19-39 years)	2.85 (1.97 to 4.13)	<.0001	1.46 (1.01 to 2.10)	0.046	1.11 (0.80 to 1.54)	0.532	1.16 (0.87 to 1.55)	0.305	0.99 (0.65 to 1.50)	0.956	0.99 (0.58 to 1.69)	0.962
Adults (40-59 years)	2.20 (1.26 to 3.82)	0.005	0.85 (0.47 to 1.52)	0.581	1.28 (0.74 to 2.20)	0.377	0.95 (0.62 to 1.43)	0.791	0.91 (0.51 to 1.63)	0.750	1.64 (0.83 to 3.26)	0.158
Older population (≥60 years)	0.42 (0.18 to 0.97)	0.043	1.24 (0.45 to 3.41)	0.675	0.76 (0.32 to 1.82)	0.532	2.02 (1.02 to 4.00)	0.045	0.36 (0.12 to 1.05)	0.062	2.67 (0.73 to 9.78)	0.137
Income (lowest-second quartile)
Preschool (2-5 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
School age (6-18 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
Adults (19-39 years)	2.90 (1.79 to 4.71)	<.0001	1.46 (0.88 to 2.41)	0.145	0.83 (0.50 to 1.36)	0.455	1.53 (0.95 to 2.46)	0.082	1.22 (0.67 to 2.23)	0.514	0.70 (0.33 to 1.48)	0.346
Adults (40-59 years)	1.30 (0.94 to 1.80)	0.109	0.82 (0.52 to 1.28)	0.371	0.74 (0.43 to 1.27)	0.274	1.28 (0.77 to 2.12)	0.335	1.59 (0.89 to 2.84)	0.119	0.86 (0.38 to 1.94)	0.719
Older population (≥60 years)	1.11 (0.92 to 1.34)	0.284	0.86 (0.69 to 1.07)	0.172	0.88 (0.69 to 1.13)	0.307	0.95 (0.74 to 1.20)	0.646	0.85 (0.60 to 1.21)	0.355	1.07 (0.69 to 1.67)	0.754
Income (third-highest quartile)
Preschool (2-5 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
School age (6-18 years)	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
Adults (19-39 years)	2.90 (2.02 to 4.15)	<.0001	1.47 (1.00 to 2.18)	0.051	1.22 (0.85 to 1.76)	0.277	1.00 (0.73 to 1.36)	0.987	1.09 (0.71 to 1.67)	0.693	0.93 (0.53 to 1.65)	0.811
Adults (40-59 years)	2.02 (1.48 to 2.75)	<.0001	1.10 (0.77 to 1.57)	0.610	0.88 (0.61 to 1.26)	0.480	0.79 (0.57 to 1.11)	0.176	0.71 (0.38 to 1.33)	0.283	1.50 (0.73 to 3.07)	0.267
Older population (≥60 years)	0.95 (0.64 to 1.41)	0.792	1.10 (0.69 to 1.76)	0.683	0.82 (0.53 to 1.27)	0.374	0.87 (0.60 to 1.26)	0.455	1.02 (0.63 to 1.66)	0.937	1.46 (0.82 to 2.63)	0.200

Abbreviations: CI, confidence interval; KNHANES, Korea National Health and Nutrition Examination Survey; OR, odds ratio.