Skip to main content

Table 3 Relative risks (rate ratios with 95% confidence intervals) for self-reported influenza-like illness (ILI) stratified by household size and acute respiratory tract infection (ARI) stratified by health care work, both by different hand-washing frequency

From: Associations of hand-washing frequency with incidence of acute respiratory tract infection and influenza-like illness in adults: a population-based study in Sweden

Subset and strata   Typical hand-washing frequency  
n 2-4 times daily 5-9 times daily 10-19 times daily ≥20 times daily Interaction p-value
Among all responding participants, outcome = ILI   Rate ratio (95% confidence interval)  
Household size 1 person1 639 1 (reference) 0.69 (0.33-1.45) 1.89 (0.91-3.91) 1.04 (0.45-2.38) 0.09
Household size 2 persons1 1137 1 (reference) 1.16 (0.62-2.19) 1.27 (0.66-2.46) 1.25 (0.63-2.50)
Household size ≥3 persons1 706 1 (reference) 1.03 (0.52-2.04) 0.88 (0.43-1.82) 0.89 (0.41-1.93)
Among gainfully employed participants, outcome = ARI       
Non-health care work2 1104 1 (reference) 1.20 (0.85-1.69) 1.39 (0.97-2.00) 1.19 (0.80-1.76) 0.13
Health care work2 170 1 (reference) 0.31 (0.11-0.90) 0.49 (0.18-1.31) 0.45 (0.18-1.13)
  1. 1adjusted for age, gender, educational level, vaccination status, child- and overall contact, household size.
  2. 2adjusted for age, gender, educational level, vaccination status, household size, physical-, child-, and long contacts, and health care work status.