Table 3.

Adjusted odds ratios for association of demographic factors with first diagnosis of confirmed COVID-19.

Characteristic	First round (n = 4621)		Second round (n = 4359)		Third round (n = 4094)		Fourth round (n = 3937)
	OR (95% CI)	p-value	OR (95% CI)	p-value	OR (95% CI)	p-value	OR (95% CI)	p-value
Sex
Female
Male	0.92 (0.48–1.75)	0.82	1.06 (0.48–2.29)	0.88	1.02 (0.75–1.39)	0.90	0.80 (0.67–0.95)	0.01
Age group (years)
0–19
20–59	1.40 (0.71–2.84)	0.37	2.58 (0.95–8.58)	0.09	1.75 (1.17–2.66)	0.01	3.30 (2.41–4.58)	<0.01
60+	1.18 (0.19–4.82)	0.84	3.00 (0.33–23.67)	0.29	1.92 (0.92–3.81)	0.09	2.30 (1.59–3.32)	<0.01
Ethnicity
Khalkh
Kazakh	2.12 (0.64–6.81)	0.24	0.00 (0.00- >99)	0.99	0.33 (0.03–1.42)	0.25	0.98 (0.47–2.03)	0.95
Buriad	0.24 (0.04–0.78)	0.06	0.40 (0.06–1.44)	0.25	0.23 (0.06–0.64)	0.02	0.70 (0.35–1.30)	0.30
Others	0.48 (0.12–1.28)	0.24	2.76 (1.03–6.35)	0.03	1.23 (0.67–2.10)	0.49	1.67 (1.05–2.64)	0.04
Region
Ulaanbaatar
Central	0.04 (0.00–0.20)	<0.01	1.11 (0.37–2.92)	0.85	0.22 (0.06–0.60)	0.02	0.17 (0.06–0.41)	<0.01
Eastern	0.72 (0.20–1.88)	0.57	0.38 (0.08–1.11)	0.14	0.64 (0.30–1.22)	0.23	0.47 (0.36–0.60)	<0.01
Khangai	0.50 (0.07–2.01)	0.41	0.59 (0.09–2.50)	0.53	0.23 (0.08–0.52)	<0.01	0.18 (0.12–0.28)	<0.01
Western	0.46 (0.15–1.23)	0.18	0.10 (0.01–0.38)	0.01	0.05 (0.01–0.16)	<0.01	0.39 (0.25–0.58)	<0.01
Occupation
Healthcare worker
Other	0.36 (0.19–0.70)	<0.01	0.10 (0.03–0.32)	<0.01	0.31 (0.20–0.48)	<0.01	0.70 (0.50–1.00)	0.06
Any comorbidity
No
Yes	1.01 (0.33–2.62)	0.99	1.27 (0.55–2.74)	0.56	1.21 (0.86–1.69)	0.29	1.38 (1.11–1.70)	<0.01

OR = Odds Ratio, CI = Confidence Interval.