. 2021 Feb 23;21:393. doi: 10.1186/s12889-021-10418-3

Table 1.

Respondent characteristics and mask usage by selected variables at three time points. Poland 2020; n = 750–818

Variable		11.05					18.05					25.05
		Total		Mask usage			Total		Mask usage			Total		Mask usage
		N^a 750	%	n	%	p	N^a 818	%	n	%	p	N^a 785	%	n	%	p
Gender	Female	371	49.5%	294	79.2%	0.0005	434	53.1%	318	73.3%	< 0.0001	398	50.7%	284	71.4%	0.0008
Gender	Male	379	50.5%	258	68.1%	0.0005	384	46.9%	226	58.9%	< 0.0001	387	49.3%	232	59.9%	0.0008
Residence	Town ≤50,000 inhabitants	395	52.7%	302	40.3%	0.06	445	54.4%	296	36.2%	0.99	387	49.3%	264	33.6%	0.15
Residence	Town > 50,000 inhabitants	355	47.3%	250	33.3%	0.06	373	45.6%	248	30.3%	0.99	398	50.7%	252	32.1%	0.15
Region	R^b < 0.5	220	29.3%	160	72.7%	> 0.65	269	32.9%	164	61.0%	> 0.004	277	35.3%	171	61.7%	> 0.055
	R 0.5–1.0	410	54.7%	302	73.7%		428	52.3%	306	71.5%		389	49.6%	268	68.9%
	R > 1.0	120	16.0%	90	75.0%		121	14.8%	74	61.2%		119	15.2%	77	64.7%
Observation	Open space	578	78.1%	407	70.4%	< 0.0001	585	73.5%	359	61.4%	< 0.0001	577	74.5%	351	60.8%	< 0.0001
Observation	Closed space	162	21.9%	141	87.0%	< 0.0001	211	26.5%	179	84.8%	< 0.0001	198	25.5%	159	80.3%	< 0.0001
Activity^a	Walking	353	51.5%	261	73.9%	< 0.0001	351	47.4%	235	67.0%	< 0.0001	368	50.7%	243	66.0%	< 0.0001
	Playing sports	154	22.4%	97	63.0%		170	23.0%	91	53.5%		150	20.7%	73	48.7%
	Shopping	179	26.1%	152	84.9%		219	29.6%	179	81.7%		208	28.7%	167	80.3%

^athe number is smaller than the number of the total observations due to the difficulties in classifications

^bbasic reproductive number