Table 2. Univariate conditional logistic regression analysis of factors associated with COVID-19 occurrence.

Factor	Unadjusted OR (95% CI)	P
Current smokers	0.83 (0.46–1.52)	0.545
Secondhand smoking exposure ≥ 1h per day	0.66 (0.3–1.20)	0.168
Low-dose alcohol intake a	0.37 (0.17–0.81)	0.013
Fruits intake daily	0.20 (0.12–0.36)	<0.001
Regular diets	0.32 (0.17–0.60)	<0.001
Lack of sleep b	1.75 (1.16–2.66)	0.008
Lunch break daily	0.55 (0.33–0.90)	0.017
Physical activities ≥ 5 times a week	2.45 (1.53–3.93)	<0.001
Hand hygiene	0.38 (0.23–0.63)	<0.001
Living alone	0.89 (0.39–2.04)	0.782
Spicy food intake ≥ 3 times a week	1.62 (0.95–2.76)	0.074
Playing Mahjong ≥ once a week	1.00 (0.60–1.66)	1.000
Cooking by oneself ≥ 5 times a week	0.65 (0.39–1.09)	0.654
Alopecia	3.63 (1.90–6.92)	<0.001
Constipation	1.07 (0.57–2.02)	0.829
Common cold ≥ 3 times a year	1.06 (0.46–2.47)	0.885

^a No more than 100g alcohol intake per week.

^b Lack of sleep referred to sleep duration <7h per night.

Abbreviation: OR, odds ratio.