Table 2.

Univariate logistic model of individual factors related to C. burnetii seropositivity in non-dairy sheep farm residents (P < 0·20, −2LL)

Variable	Category	Frequency (N) (N = 266)	Sero-prevalence (%)	OR (95% CI)
Gender*	Male	144	57·6	1·77 (1·09–2·88)
	Female	122	43·4	Reference
Age (years)*	12–19	21	57·1	2·04 (0·72–5·76)
	20–39	45	51·1	1·60 (0·70–3·63)
	40–49	68	58·8	2·18 (1·03–4·63)
	50–59	84	50·0	1·53 (0·74–3·13)
	>60	48	39·6	Reference
Work and/or live on farm	Work and live	188	53·7	1·61 (0·83–3·15)
	Work, but not live	35	48·6	1·31 (0·53–3·22)
	Not work, but live	43	41·9	Reference
Function	Farmer	136	58·8	2·51 (1·42–4·44)
	Spouse	80	36·3	Reference
	Child†	39	53·9	2·05 (0·94–4·46)
	Other‡	11	54·6	2·11 (0·59–7·53)
How often in stable	Every day	185	55·7	Reference
	Every week	56	41·1	0·56 (0·30–1·02)
	Every month	10	50·0	0·80 (0·22–2·84)
	Less than once a month/never	15	33·3	0·40 (0·13–1·21)
Amount of work at farm*	Full working week	61	63·9	2·39 (1·25–4·56)
	Up to half a working week	97	52·9	1·49 (0·86–2·59)
	Never/occasionally	108	42·6	Reference
Feed sheep*	Yes	225	55·6	3·41 (1·63–7·14)
	No	41	26·8	Reference
Load and unload sheep	Yes	194	56·2	2·14 (1·23–3·72)
	No	72	37·5	Reference
General healthcare of sheep	Yes	201	55·7	2·15 (1·21–3·82)
	No	65	36·9	Reference
Remove manure	Yes	180	57·8	2·31 (1·36–3·92)
	No	86	37·2	Reference
Spread manure*	Yes	124	58·9	1·80 (1·10–2·92)
	No	142	44·4	Reference
Clean stables	Yes	167	56·3	1·75 (1·06–2·89)
	No	99	42·4	Reference
Administrative work	Yes	193	54·4	1·62 (0·94–2·78)
	No	73	42·5	Reference
Wear overalls or boots*	Yes	234	54·3	3·03 (1·35–6·84)
	No	32	28·1	Reference
Contact with cattle at own or other farm*§	Yes	172	63·4	4·29 (2·49–7·40)
	No	94	28·7	Reference
Contact with horses at own or other farm*§	Yes	145	59·3	2·07 (1·27–3·38)
	No	121	41·3	Reference
Contact with pigs at own farm*§	Yes	24	37·5	0·54 (0·23–1·29)
	No	242	52·5	Reference
Indirect contact with poultry at own farm*∥	Yes	93	57·0	1·44 (0·87–2·39)
	No	173	48·0	Reference
Indirect contact with rats at own farm*∥	Yes	45	64·4	1·93 (0·99–3·76)
	No	221	48·4	Reference
Contact with goats at other farm*§	Yes	32	62·5	1·70 (0·79–3·63)
	No	234	49·6	Reference
Contact with sheep at other farm*§	Yes	102	60·8	1·89 (1·14–3·12)
	No	164	45·1	Reference
Contact with dogs at other farm*§	Yes	112	58·9	1·72 (1·05–2·82)
	No	154	45·5	Reference
Indirect contact with poultry at other farm∥	Yes	38	63·2	1·78 (0·87–3·61)
	No	228	49·1	Reference
Indirect contact with cats at other farm*∥	Yes	81	59·3	1·60 (0·95–2·72)
	No	185	47·6	Reference
Direct contact with wool*	Yes	113	60·2	1·89 (1·15–3·09)
	No	153	44·4	Reference
Direct contact with hay, straw or animal feed*	Yes	228	54·8	2·98 (1·41–6·29)
	No	38	29·0	Reference
Direct contact with raw milk	Yes	72	62·5	1·91 (1·10–3·32)
	No	193	46·6	Reference
Drink raw milk from cattle*	Yes	45	66·7	2·17 (1·11–4·26)
	No	221	48·0	Reference
Direct contact with cattle manure	Yes	110	68·2	3·30 (1·97–5·52)
	No	155	39·4	Reference
Direct contact with live-born animals during lambing period	Yes	246	53·3	3·42 (1·21–9·69)
	No	20	25·0	Reference
Direct contact with dead-born animals/placenta*	Yes	210	54·3	1·84 (1·01–3·35)
	No	56	39·3	Reference
Tick bite*	Yes	61	42·6	0·64 (0·36–1·14)
	No	205	53·7	Reference
Did not work in animal husbandry/agriculture in the past	Yes	114	39·5	0·44 (0·27–0·72)
	No	152	59·9	Reference
Employment in cattle sector in the past*	Yes	107	64·5	2·49 (1·50–4·14)
	No	159	42·1	Reference
Worked in animal transport/ transport of agricultural products in the past*	Yes	37	70·3	2·56 (1·21–5·42)
	No	229	48·0	Reference
As a child lived at:	Cattle farm	151	59·6	2·04 (1·18–3·53)
	Other kind of farm	34	35·3	0·75 (0·33–1·73)
	No farm	81	42·0	Reference
As a child worked in animal care/with manure/hay/in vegetation care*	Yes	178	56·2	1·85 (1·10–3·11)
	No	88	40·9	Reference

N, Total number of individuals; OR, odds ratio; CI, confidence interval, −2LL, likelihood ratio test.

^*Variables included in subsequent multivariate individual analyses before manual backward elimination.

^†Children aged <18 years (n = 17) and older children (n = 22) of the farmer.

^‡Employees, shepherds, other family members.

^§See animals at <5 m or touch animals.

^∥See animals at <5 m.