Predisposing factors to acquisition of acute respiratory tract infections in the community: a systematic review and meta-analysis

BACKGROUND: Preventing respiratory tract infections (RTIs) could have profound effects on quality of life, primary care workload, antibiotic prescribing and stewardship. We aimed to identify factors that increase and decrease RTI acquisition within Organisation for Economic Cooperation and Development (OECD) member countries. METHODS: Systematic search of Medline, Embase, Cochrane and ISI Web of Knowledge for studies conducted up to July 2020 reporting predisposing factors for community RTI acquisition. Pooled odds ratios were calculated using a random-effects model. RESULTS: 23 studies investigated risk factors associated with community-acquired pneumonia (n = 15); any RTI (n = 4); influenza like illness (n = 2); and lower RTI (n = 2). Demographic, lifestyle and social factors were: underweight BMI (pooled odds ratio (OR(p) 2.14, 95% CI 1.58 to 2.70, p = 0.97); male sex (OR(p) 1.30, 95% CI 1.27 to 1.33, p = 0.66); contact with pets (OR(p) 1.35, 95% CI 1.16 to 1.54, p = 0.72); contact with children (OR(p) 1.35, 95% CI 1.15 to 1.56, p = 0.05); and ex-smoking status (OR(p) 1.57, 95% CI 1.26 to 1.88, p = 0.76). Health-related factors were: chronic liver condition (OR(p) 1.30, 95% CI 1.09 to 1.50, p = 0.34); chronic renal condition (OR(p) 1.47, 95% CI 1.09 to 1.85, p = 0.14); and any hospitalisation in previous five years (OR(p) 1.64, 95% CI 1.46 to 1.82, p = 0.66). CONCLUSIONS: We identified several modifiable risk factors associated with increased likelihood of acquiring RTIs in the community, including low BMI, contact with children and pets. Modification of risk factors and increased awareness of vulnerable groups could reduce morbidity, mortality and antibiotic use associated with RTIs. PROSPERO REGISTRATION: CRD42019134176. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-021-06954-3.