Table 2. Multivariate analysis of risk factors potentially associated with the Giardia outbreak from a case–control study, Municipality A, Bologna province, north-eastern Italy, November 2018−May 2019 (n = 59 cases, n = 60 controls) .

Risk factor	OR	CI 95%		p value
Sex, female	1.78	0.56	5.67	0.33
Age (years)	0.99	0.95	1.02	0.39
Comorbidities	1.00	0.21	4.70	0.99
Consumption of tap water (n of glasses/day)a	1.98	1.40	2.80	< 0.01
Consumption of water from drinking fountain	4.03	0.60	27.29	0.15
Consumption of bottled water	1.91	0.43	8.40	0.39
Use of domestic water filtration systems	0.11	0.02	0.51	0.01
Contact with animals/owning pets	2.12	0.66	6.78	0.21
Gardening activities/cultivating a vegetable garden at home	4.44	1.14	17.29	0.03
Attending swimming pool	1.24	0.28	5.58	0.78
Weekly consumption of raw vegetables and fruits (n of servings/week)b	0.25	0.13	0.47	< 0.01
Residing in a high attack rate street	4.07	1.01	16.38	0.05

CI: confidence interval; OR: odds ratio.

^a OR was calculated for each additional glass of tap water per day.

^b OR was calculated for each additional serving of raw vegetables and fruits per week.