. 2020 Sep 25;7:545328. doi: 10.3389/fvets.2020.545328

Table 3.

Results from univariable and multivariable logistic regression models using the chronic status (case/control) for herds experiencing particularly long breakdowns as the outcome variable.

Variable (number of herds with information)	Exposure level	Controls		Cases		Total	OR	95% CI	P-value^a	OR	95% CI	P-value^a	P-value^b
		Number	%	Number	%
							Univariable			Multivariable
Relative change in herd size at the disclosing bTB-positive herd test (%) (n = 1,741)	1Q (−100 – −7.2)	339	24.2	89	26.2	428	1	NA	0.891
	2Q (−7.21–2.3)	359	25.6	84	24.7	443	0.89	0.6–1.2
	3Q (2.31–14.3)	360	25.7	87	25.6	447	0.92	0.7–1.3
	4Q (14.31–3,800)	343	24.5	80	23.5	423	0.89	0.6–1.3
Median herd size in the year the bTB breakdown started (n = 1,790)	Small	424	29.4	24	6.9	448	1	NA	<0.001	1	NA	–	<0.001
	Medium	742	51.4	148	42.7	890	3.52	2.3–5.6		4.85	2.6–9.7	<0.001
	Large	277	19.2	175	50.4	452	11.16	7.2–17.9		9.45	4.8–19.8	<0.001
In-degree in the 3 years prior to the start of the bTB breakdown (n = 1,739)	0	377	26.2	54	18	431	0.57	0.4–0.8
	1	330	22.9	74	24.7	404	0.89	0.6–1.3
	2–3	405	28.1	90	30	495	0.89	0.6–1.2
	>3	327	22.7	82	27.3	409	1	NA	0.018
Number of incoming animals in the 3 years prior to the start of the bTB breakdown (n = 1,739)	0	377	26.2	54	18	431	0.32	0.2–0.4		0.56	0.3–0.9	0.039
	1	303	21.1	53	17.7	356	0.39	0.3–0.6		0.83	0.5–1.4	0.49
	2–4	464	32.2	62	20.7	526	0.3	0.2–0.4		0.49	0.3–0.8	0.007
	>4	295	20.5	131	43.6	426	1	NA	<0.001	1	NA	–	0.027
County-level herd prevalence in the year prior to the start of the bTB breakdown (n = 1,660)	0	900	63.6	104	42.3	1004	1	NA	<0.001	1	NA	–	0.004
	0.01–0.06	260	18.4	61	24.8	321	2.03	1.4–2.9		1.89	1.1–3.1	0.012
	0.061–0.1	138	9.8	36	14.6	174	2.26	1.5–3.4		1.51	0.8–2.8	0.191
	0.11–0.2	92	6.5	30	12.2	122	2.82	1.8–4.4		1.34	0.7–2.6	0.394
	0.21–1	24	1.7	15	6.1	39	5.41	2.7–10.5		2.78	1–7.4	0.044
Production type (n = 1,790)	Beef/fattening	1,203	83.4	305	87.9	1508	1	NA	<0.001
	Bullfighting	6	0.4	19	5.5	25	12.49	5.2–34.5
	Dairy/mixed	234	16.2	23	6.6	257	0.39	0.3–0.6
Province (n = 1,790)	Avila	208	14.4	70	20.2	278	1	NA	<0.001	1	NA	–	0.002
	Burgos	144	10	10	2.9	154	0.21	0.1–0.4		1.06	0.4–2.6	0.903
	Leon	178	12.3	24	6.9	202	0.40	0.2–0.6		1.43	0.6–3.2	0.408
	Palencia	57	4	9	2.6	66	0.47	0.2–0.9		0.55	0.1–1.8	0.358
	Salamanca	544	37.7	155	44.7	699	0.85	0.6–1.2		1.07	0.6–1.9	0.82
	Segovia	128	8.9	24	6.9	152	0.56	0.3–0.9		1.55	0.7–3.5	0.285
	Soria	52	3.6	19	5.5	71	1.09	0.6–1.9		4.73	1.9–11.7	<0.001
	Valladolid	15	1	11	3.2	26	2.18	0.9–4.9		5.32	1.5–17.4	0.007
	Zamora	117	8.1	25	7.2	142	0.63	0.4–1		1.91	0.8–4.4	0.135
Number of SIT reactors in the disclosing test (n = 1,790)	0	78	5.4	143	41.2	221	16.93	11.9–24.2		1.69	1.1–3	0.05
	1	831	57.6	90	25.9	921	1	NA	<0.001	1	NA	–	<0.001
	2–4	461	31.9	83	23.9	544	1.67	1.2–2.3		1.37	0.8–2.2	0.198
	≥5	73	5.1	31	8.9	104	3.92	2.4–6.3		2.75	1.25.9	0.011
Number positive to bacteriology in the disclosing test (n = 1,790)	0	1,321	91.5	102	29.4	1423	1	NA	<0.001	1	NA	–	<0.001
	1	109	7.6	150	43.2	259	17.82	13–24.6		26.53	16.3–44.1	<0.001
	2	10	0.7	32	9.2	42	41.44	20.5–91.1		25.48	9.1–75.9	<0.001
	≥3	3	0.2	63	18.2	66	271.9	98.7–1,126.5		89.96	28.1–408	<0.001
Number of days between the disclosing and follow-up tests (n = 1,790)	0–70	382	26.5	62	17.9	444	1	NA	<0.001	1	NA	–	<0.001
	71–90	601	41.6	66	19	667	0.68	0.5–0.9		0.93	0.5–1.6	0.792
	91–124	401	27.8	76	21.9	477	1.17	0.8–1.7		1.49	0.9–2.6	0.146
	>124	59	4.1	143	41.2	202	14.93	10–22.6		14.4	7.6–27.7	<0.001

Walds test.

Chi-square test.

bTB, bovine tuberculosis; OR, odds ratio; SIT, single intradermal test.