Table 6.

Logistic regression of a case control study of mastitis.

	Univariate analysis			Multivariate analysis Model 1 (n = 192)				Multivariate analysis Model 2 (n = 192) (No demographic variables)
	Odds Ratio	(95% CI)		Odds Ratio	(95% CI)		P	Odds Ratio	(95% CI)		P
Income
<Aus$70,000	Reference			Reference				-	-	-	-
>Aus$70,001	0.37	0.20	0.68	0.31	0.13	0.71	0.006	-	-	-	-
Missing	0.67	0.22	2.06	0.28	0.06	1.14	0.120	-	-	-	-
PHI
No	Reference			Reference				-	-	-	-
Yes	0.27	0.14	0.51	0.23	0.10	0.55	0.001	-	-	-	-
Difficulty breastfeeding
No	Reference			Reference				Reference
Yes	7.76	3.86	15.58	6.32	2.53	15.76	0.000	4.64	2.11	10.22	0.001
Cracked nipple
No	Reference			Reference				Reference
Yes	15.02	5.60	40.33	9.34	2.99	29.20	0.000	9.39	3.24	27.21	0.000
Tight bra
No	v			Reference				Reference
Yes	2.31	1.21	4.41	3.47	1.30	9.22	0.013	2.38	1.06	5.36	0.036
Baby nasal S. aureus
No	Reference			Reference				Reference
Yes	3.70	1.85	7.40	3.23	1.30	8.27	0.017	2.70	1.19	6.14	0.018
Missing	4.56	1.41	14.71	3.49	0.78	15.50	0.101	3.20	0.83	12.38	0.092

(n = 98 women with mastitis and 94 breastfeeding controls). Melbourne, Australia, 2002–2004. Model 1 includes income, private health insurance, difficulty with breastfeeding, damaged nipple, tight bra, baby nasal S. aureus, and Model 2 includes difficulty with breastfeeding, damaged nipple, tight bra and baby nasal S. aureus.