Abstract
BACKGROUND: We estimated the incidence, viral aetiology and risk factors of acute lower respiratory infection (ALRI) and severe ALRI among community-dwelling older adults at four sites in India. METHODS: Adults ≥60 years were recruited and followed between July 2018 and March 2023. Each week, trained nurses screened all participants for ALRI using modified British Thoracic Society criteria. ALRI was further categorised as severe ALRI if the respiratory rate was >30 breaths per minute or the SPO(2) was <94% or the patient was hospitalised with respiratory symptoms. Combined nasal and throat swabs from ALRI cases were tested for multiple viral pathogens. The incidence of ALRI, severe ALRI and respiratory hospitalisation per 1000 person-years (TPY) was estimated. Adjusted rate ratios (aRR) were calculated by multilevel Poisson regression to identify risk factors for ALRI and severe ALRI. RESULTS: We followed 7240 participants for 19 914 person-years; 59.5% were women. Their mean age was 66.2 years. The incidence of ALRI, severe ALRI and respiratory hospitalisation was 98.0/TPYs, 22.1/TPYs and 12.1/TPYs, respectively. Males (aRR: 1.2), those with body mass index <18.5 kg/m(2) (aRR: 1.6) or ≥30 (aRR: 1.5), coronary artery disease (aRR: 1.5), current or past tuberculosis (aRR: 2.4), chronic respiratory disease (aRR: 5.4) and the use of solid fuel in the household (aRR: 2.0) had higher risk of severe ALRI. Viruses were detected in 16.8% of ALRI cases, influenza (8.8%) was the most detected viral pathogen followed by rhinovirus (2.7%). CONCLUSION: Rates of ALRI and severe ALRI were high; malnutrition, chronic morbidities and the use of solid fuel were important risk factors for severe ALRI.