Table 3. Weighted odds ratio of before and during the pandemic, weighted % (95% CI), data was collected from the KNHANES

	2007-2009 versus 1998–2005 (reference)	P-value	2010-2012 versus 2007-2009 (reference)	P-value	2013-2015 versus 2010-2012 (reference)	P-value	2016-2019 versus 2013-2015 (reference)	P-value	2020 versus 2016-2019 (reference)	P-value	2021 versus 2020 (reference)	P-value
Overall	3.74 (3.34 to 4.20)	<.0001	0.75 (0.67 to 0.85)	<.0001	0.89 (0.77 to 1.03)	0.109	0.92 (0.80 to 1.05)	0.212	1.05 (0.87 to 1.26)	0.621	0.86 (0.67 to 1.10)	0.225
Age group
5-19	9.94 (3.76 to 26.33)	<0.001	0.13 (0.02 to 1.04)	0.055	0.74 (0.05 to 11.93)	0.831	1.61 (0.10 to 25.84)	0.736	NA	NA	NA	NA
20-29	2.69 (1.68 to 4.29)	<0.001	0.80 (0.45 to 1.43)	0.443	0.71 (0.36 to 1.43)	0.339	0.90 (0.44 to 1.81)	0.760	1.05 (0.36 to 3.08)	0.926	NA	NA
30-39	3.06 (2.38 to 3.93)	<0.001	0.67 (0.49 to 0.91)	0.010	0.81 (0.55 to 1.19)	0.276	0.66 (0.44 to 1.00)	0.052	0.78 (0.37 to 1.67)	0.528	0.66 (0.21 to 2.10)	0.482
40-49	3.69 (2.91 to 4.69)	<0.001	0.77 (0.59 to 1.02)	0.065	0.80 (0.58 to 1.10)	0.172	0.89 (0.65 to 1.20)	0.436	0.92 (0.55 to 1.56)	0.769	0.71 (0.35 to 1.43)	0.337
50-59	3.40 (2.69 to 4.31)	<0.001	0.75 (0.59 to 0.95)	0.017	0.94 (0.73 to 1.22)	0.657	0.78 (0.60 to 1.00)	0.049	1.17 (0.81 to 1.69)	0.412	1.15 (0.70 to 1.87)	0.582
60-69	3.39 (2.67 to 4.30)	<0.001	0.67 (0.53 to 0.85)	0.001	0.97 (0.75 to 1.24)	0.777	0.90 (0.71 to 1.14)	0.384	1.07 (0.76 to 1.50)	0.707	0.76 (0.48 to 1.18)	0.219
≥70	3.13 (2.35 to 4.17)	<0.001	0.80 (0.62 to 1.04)	0.093	0.76 (0.58 to 1.01)	0.055	1.19 (0.91 to 1.55)	0.207	0.98 (0.64 to 1.51)	0.931	0.88 (0.52 to 1.50)	0.639
Sex
Male	3.73 (3.23 to 4.31)	<0.001	0.72 (0.61 to 0.85)	<0.001	0.90 (0.74 to 1.08)	0.243	0.90 (0.76 to 1.08)	0.251	1.09 (0.87 to 1.38)	0.461	0.79 (0.57 to 1.09)	0.152
Female	3.75 (3.16 to 4.44)	<0.001	0.80 (0.67 to 0.96)	0.014	0.89 (0.72 to 1.09)	0.254	0.93 (0.76 to 1.14)	0.480	0.98 (0.70 to 1.37)	0.893	0.98 (0.66 to 1.46)	0.919
Region of residence
Urban	3.85 (3.39 to 4.38)	<0.001	0.78 (0.68 to 0.89)	<.0001	0.82 (0.69 to 0.97)	0.018	0.95 (0.81 to 1.11)	0.499	1.07 (0.87 to 1.31)	0.545	0.87 (0.66 to 1.14)	0.316
Rural	3.30 (2.60 to 4.21)	<0.001	0.65 (0.50 to 0.84)	0.001	1.29 (0.97 to 1.70)	0.076	0.81 (0.61 to 1.06)	0.120	0.95 (0.69 to 1.30)	0.732	0.81 (0.53 to 1.22)	0.310
Education
Elementary school or lower education	5.00 (4.11 to 6.08)	<0.001	0.75 (0.60 to 0.93)	0.009	0.88 (0.67 to 1.15)	0.342	1.22 (0.93 to 1.60)	0.146	1.18 (0.75 to 1.88)	0.473	0.62 (0.30 to 1.29)	0.202
Middle school	4.17 (3.17 to 5.48)	<0.001	0.65 (0.48 to 0.88)	0.006	1.05 (0.75 to 1.47)	0.777	0.92 (0.67 to 1.27)	0.608	1.06 (0.66 to 1.72)	0.804	0.71 (0.37 to 1.39)	0.318
High school	3.64 (2.96 to 4.48)	<0.001	0.73 (0.58 to 0.92)	0.009	1.12 (0.87 to 1.42)	0.378	0.74 (0.59 to 0.93)	0.010	1.38 (1.00 to 1.91)	0.052	0.71 (0.45 to 1.12)	0.139
College or higher education	3.12 (2.53 to 3.84)	<0.001	0.84 (0.67 to 1.04)	0.107	0.72 (0.56 to 0.91)	0.007	1.02 (0.81 to 1.27)	0.892	0.85 (0.62 to 1.18)	0.335	1.15 (0.77 to 1.70)	0.494
Household income
Lowest quartile	3.46 (2.77 to 4.32)	<0.001	0.78 (0.60 to 1.01)	0.055	0.81 (0.60 to 1.07)	0.140	1.04 (0.79 to 1.38)	0.759	0.86 (0.56 to 1.30)	0.464	1.10 (0.64 to 1.88)	0.736
Second quartile	3.71 (2.96 to 4.64)	<0.001	0.74 (0.58 to 0.94)	0.013	0.94 (0.71 to 1.24)	0.648	0.96 (0.74 to 1.26)	0.770	1.09 (0.79 to 1.52)	0.595	0.72 (0.44 to 1.16)	0.173
Third quartile	4.58 (3.67 to 5.71)	<0.001	0.69 (0.55 to 0.88)	0.003	0.87 (0.67 to 1.14)	0.320	0.94 (0.73 to 1.22)	0.658	1.05 (0.69 to 1.57)	0.834	0.78 (0.47 to 1.30)	0.335
Highest quartile	3.66 (2.92 to 4.59)	<0.001	0.81 (0.63 to 1.03)	0.079	0.94 (0.71 to 1.26)	0.694	0.79 (0.60 to 1.04)	0.089	1.18 (0.86 to 1.60)	0.303	0.95 (0.63 to 1.44)	0.812

Abbreviations: CI, confidence interval; KNHANES, Korea National Health and Nutrition Examination Survey.
The numbers in bold indicate a significant difference (p<0.05).