Table 3. Participation according to Baseline characteristics of participants of the PSMAR breast cancer screening program in the BHA affected by the COVID-19 pandemic in the area of reference of Parc de Salut Mar (PSMAR), in Barcelona, Spain in the period 2012–2021 by screening round.

		Pre-COVID 4 round		Pre-COVID 3 round		Pre-COVID 2 round		Pre-COVID 1 round		Pre-COVID total		Post-COVID +1 round		Difference post–pre	p valor
		(2012–2013)		(2014–2015)		(2016–2017)		(2018–2019)		(2012–2019)		(2020–2021)
		n	%	n	%	n	%	n	%	n	%	n	%
Age group	50–54	4550	49.98	4596	48.40	4546	48.10	4434	49.20	18,126	48.91	4073	46.59	−2.32%	<0.001*
	55–59	3912	54.69	3901	53.11	3985	52.65	4089	53.58	15,887	53.50	4038	51.12	−2.37%	<0.001*
	60–64	3784	56.59	3729	56.73	3710	55.44	3780	56.71	15,003	56.36	3664	53.64	−2.73%	<0.001*
	65–70	3325	58.46	3352	58.23	3225	57.66	3220	59.77	13,122	58.52	3020	54.87	−3.65%	<0.001*
Socioeconomic index level	Low	3282	73.62	3223	72.07	3201	73.23	3226	73.80	12,932	73.18	3065	67.57	−5.61%	<0.001*
	Middle-low	1603	69.60	1612	68.42	1620	69.56	1630	69.72	6465	69.32	1586	63.29	−6.03%	<0.001*
	Middle-high	8363	54.99	8537	54.49	8508	53.63	8626	55.45	34,034	54.63	8164	52.33	−2.30%	<0.001*
	High	2323	34.87	2206	33.06	2137	31.70	2041	31.74	8707	32.85	1981	31.27	−1.58%	0.016*
Type of screening
Prevalent	First invitation	2058	46.68	1957	42.81	1876	43.92	1850	48.29	7741	45.32	2133	41.71	−3.61%	<0.001*
	Previous nonparticipant	812	9.56	771	8.92	750	8.29	763	8.47	3096	8.80	802	9.48	0.69%	0.05*
	Total	2870	22.24	2728	20.65	2626	19.71	2613	20.35	10,837	20.73	2935	21.63	0.90%	0.024*
Incident	Regular participant	12,003	89.51	12,116	89.89	12,095	89.63	12,098	90.35	48,312	89.84	11,166	85.43	−4.41%	<0.001*
	Irregular participant	698	30.15	734	29.58	745	29.92	812	32.95	2989	30.66	695	29.74	−0.92%	0.38
	Total	12,701	80.77	12,850	80.52	12,840	80.33	12,910	81.43	51,301	80.76	11,861	76.98	−3.78%	<0.001*
Total		15,571	54.39	15,578	53.41	15,466	52.78	15,523	54.09	62,138	53.66	14,795	51.06	−2.60%	<0.001*

Pre-COVID totals calculated as the sum of the four pre-COVID screening rounds. Percentages show the proportion of participants among women invited for each category. p values obtained with chi-square test comparing the total pre- and post-COVID proportions. * indicates statistical significance, with a p-value < of equal to 0.05.