Vitamin D3and gargling for the prevention of upper respiratory tract infections: a randomized controlled trial

BMC Infectious Diseases

Table 3 Frequency, severity, duration and viral load associated with URTI according to gargling allocation

Outcome measure	Clinical URTI				Laboratory confirmed URTI
Outcome measure	Gargling (n = 256)	Control (n = 236)	Effect measure (95% CI)	P value	Gargling (n = 254)	Control (n = 235)	Effect measure (95% CI)	P value
Imputed URTI episodes, No. (%)	106 (35.3)	100 (33.3)	^*RR: 1.1 (0.78-1.44)	0.69
Complete case URTI episodes, No. (%)	85 (33.2)	65 (27.5)	^*RR: 1.2 (0.92-1.57)	0.19	33 (13.0)	37 (18.7)	^*RR:0.82 (0.53-1.26)	0.36
^€Viral load, mean (SD)					6.24 (1.3)	5.95 (1.5)		0.43
^†Symptom duration, mean days (SD)	6.2 (1.3)	6.0 (1.6)	^*HR: 0.85 (0.38-1.89)	0.69	5.9 (1.3)	6.1 (1.4)	^*HR: 0.43 (0.56-4.0)	0.43
^†Symptom severity, mean (SD)	225.3 (123.9)	191.8 (105.1)		0.13	210.5 (105.3)	191.8 (98.8)		0.49

RR: relative risk, HR: Hazard ratio.
^*The Poisson and Cox regression models were adjusted exclusively for randomization strata: vitamin D allocation, gargling allocation, year of participation and type of housing.
^€Viral load was measured as log₁₀ viral copies/mL.
^†Symptom duration and severity was measured only in participants who self-reported illness (ie. not for adjudicated events), n = 106. For clinical URTI, n = 55 and n = 51 in the gargling and control groups respectively. For laboratory confirmed URTI n = 26 and n = 30 in the gargling and control groups respectively.

ISSN: 1471-2334