Table 2.

Multivariate unadjusted and adjusted^* relative risk of health-service utilization (HSU) for upper respiratory tract infection (URTI) in relation to serum 25-hydroxyvitamin D and vitamin D supplementation, TARGet Kids! cohort, Toronto, Canada, 2008–2013

	Any HSU (Total HSU)†				Hospital admissions (HA)‡				Emergency department visits (ED)‡				Outpatient sick visits (SV)‡
	RR	95 % CI	aRR	95 % CI	RR	95 % CI	aRR	95 % CI	RR	95 % CI	aRR	95 % CI	RR	95 % CI	aRR	95 % CI
Serum 25-hydroxyvitamin D (n 2962)§	1·01	0·99, 1·02	1·01	0·99, 1·02	1·01	0·93, 1·10	1·01	0·92, 1·10	0·99	0·95, 1·02	0·99	0·96, 1·02	1·01	0·99, 1·02	1·01	1·00, 1·02
Prenatal vitamin D supplementation (n 4672)	1·01	0·90, 1·12	0·95	0·86, 1·06	0·89	0·44, 1·78	0·89	0·44, 1·82	0·98	0·76¸ 1·28	0·90	0·70, 1·18	1·01	0·91¸1·13	0·96	0·86, 1·07
Child vitamin D supplementation (n 4132)	1·00	0·99, 1·01	1·01	1·00, 1·02	1·03	0·98, 1·08	1·03	0·98, 1·08	0·98	0·95, 1·01	0·99	0·96, 1·02	1·00	0·99, 1·01	1·01	1·00, 1·02

RR, relative risk; aRR, adjusted relative risk.

^*Adjusted for age, sex, BMI Z-score, number of children in the household and day care/pre-school attendance.

^†Any HSU for URTI (HA+ED+SV).

^‡Risk of one hospital admission, one emergency department visit or one outpatient sick visit for URTI.

^§Serum 25-hydroxyvitamin D in 10 nmol/l increments.