Table 3. Difference between before and during the COVID-19 pandemic by the ratio of wORs on osteoporosis, weighted % (95% CI), in the data obtained from the KNHANES

	Overall		Pre-pandemic (2001-2019)		During-pandemic (2019-2021)		Ratio of wORs (95% CI)
	wORs (95% CI)	p-value	wORs (95% CI)	p-value	wORs (95% CI)	p-value	wORs (95% CI)	p-value
Osteoporosis
Age group, years
50-59	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
60-69	3.09 (2.79 to 3.42)	<0.001	2.98 (2.68 to 3.32)	<0.001	3.40 (2.81 to 4.12)	<0.001	1.14 (0.92 to 1.42)	0.239
70-79	5.49 (4.94 to 6.10)	<0.001	5.33 (4.77 to 5.96)	<0.001	6.97 (5.78 to 8.41)	<0.001	1.31 (1.05 to 1.63)	0.016
≤ 80	4.95 (4.34 to 5.65)	<0.001	4.46 (3.84 to 5.17)	<0.001	7.44 (6.02 to 9.20)	<0.001	1.67 (1.29 to 2.16)	<0.001
Sex
Male	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Female	15.39 (13.37 to 17.71)	<0.001	15.72 (13.52 to 18.27)	<0.001	15.99 (12.60 to 20.30)	<0.001	1.02 (0.77 to 1.35)	0.906
Region of residence
Urban	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Rural	1.29 (1.19 to 1.40)	<0.001	1.33 (1.21 to 1.45)	<0.001	1.31 (1.14 to 1.51)	<0.001	0.98 (0.83 to 1.16)	0.859
Household income
Lowest and second quartile	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Third and highest quartile	2.15 (2.00 to 2.32)	<0.001	2.07 (1.91 to 2.25)	<0.001	2.67 (2.35 to 3.03)	<0.001	1.29 (1.11 to 1.50)	0.001
Education level
High school or lower education	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
College or higher education	3.33 (3.06 to 3.62)	<0.001	3.39 (3.08 to 3.72)	<0.001	3.87 (3.40 to 4.39)	<0.001	1.14 (0.97 to 1.34)	0.102
BMI, kg/m2*
Underweight	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Normal and overweight	1.16 (1.08 to 1.24)	<0.001	1.15 (1.07 to 1.24)	<0.001	1.24 (1.10 to 1.39)	<0.001	1.08 (0.94 to 1.24)	0.286
Obese	1.59 (1.30 to 1.95)	<0.001	1.50 (1.20 to 1.87)	<0.001	2.31 (1.68 to 3.17)	<0.001	1.54 (1.05 to 2.27)	0.029
Menopausal status
Postmenopausal	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Premenopausal	3.76 (3.24 to 4.36)	<0.001	3.65 (3.08 to 4.33)	<0.001	4.19 (3.36 to 5.23)	<0.001	1.15 (0.87 to 1.52)	0.333
Osteoporosis with menopause
Age group, years
50-59	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
60-69	3.65 (3.26 to 4.09)	<0.001	3.46 (3.07 to 3.91)	<0.001	4.30 (3.47 to 5.33)	<0.001	1.24 (0.97 to 1.59)	0.084
70-79	5.99 (5.31 to 6.75)	<0.001	5.69 (5.01 to 6.47)	<0.001	8.57 (6.88 to 10.68)	<0.001	1.51 (1.17 to 1.94)	0.002
≤ 80	4.51 (3.87 to 5.25)	<0.001	3.89 (3.27 to 4.63)	<0.001	7.84 (6.17 to 9.96)	<0.001	2.02 (1.50 to 2.71)	<0.001
Region of residence
Urban	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Rural	1.34 (1.22 to 1.47)	<0.001	1.37 (1.23 to 1.52)	<0.001	1.41 (1.19 to 1.66)	<0.001	1.03 (0.84 to 1.25)	0.775
Household income
Lowest and second quartile	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Third and highest quartile	1.98 (1.82 to 2.16)	<0.001	1.89 (1.73 to 2.07)	<0.001	2.52 (2.18 to 2.91)	<0.001	1.33 (1.12 to 1.58)	0.001
Education level
High school or lower education	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
College or higher education	2.57 (2.34 to 2.82)	<0.001	2.47 (2.23 to 2.75)	<0.001	3.38 (2.93 to 3.89)	<0.001	1.37 (1.15 to 1.63)	<0.001
BMI, kg/m2*
Underweight	1.00 (reference)		1.00 (reference)		1.00 (reference)		1.00 (reference)
Normal and overweight	1.13 (1.04 to 1.22)	0.005	1.13 (1.03 to 1.23)	0.007	1.13 (0.99 to 1.29)	0.080	1.00 (0.85 to 1.17)	1.000
Obese	1.50 (1.19 to 1.90)	0.001	1.45 (1.11 to 1.88)	0.006	1.79 (1.24 to 2.57)	0.002	1.23 (0.79 to 1.94)	0.359

BMI, body mass index; CI, confidence interval; KNHANES, Korea National Health and Nutrition Examination Survey.
The KNHANES data from 2012, 2013, and 2014 were excluded.
According to the Asian-Pacific guidelines, the BMI is divided into three groups: underweight (> 18.5 kg/m²), normal and overweight (18.5-24.9 kg/m²), and obese (≤ 25.0 kg/m²).
Bolded data indicate significant differences in the regression model (P <0.05)