Effects of A Small Dose of Biomass Smoke on The Morbidity of Community-acquired Pneumonia; A Multivariate Regression Analysis of 1600 Patients

Abstract

The annual number of deaths from pneumonia has markedly increased with the decrease in the prevalence of smoking since the 1980s in Japan. A small dose of biomass smoke functions as a disinfectant against droplet-borne biologic microbes, and smokeless residence has been proposed as one cause of the high incidence of pneumonia. The present study retrospectively investigated the effects of biomass smoke on the morbidity of pneumonia using a multivariate regression analysis.

This study analyzed 1600 patients with pneumonia or parapneumonic pleuritis between 2010 to 2021. A total of 181 health examinees for chest CT screening in 2019 were used as the control group. The following variables were selected for the analysis; sex, age, the smoking status, nursing care status, comorbidities, disease history, vaccination status, season, residence smoking status, pathogens, disease severity, medical interventions, and disease prognosis. The primary outcome was the morbidity of pneumonia, and the secondary outcomes were disease prognosis and the detection of pathogens.

Most pathogens were resident flora of droplet-borne contamination. A smokeless environment significantly increased the detection rate of pathogens associated with sever disease and a poor outcome. Patients with a low performance status had a significantly worse outcome. Indoor seasons and smokeless environments significantly increased morbidity, while vaccination and current smoking markedly reduced morbidity.

The main cause of pneumonia was speculated to be droplet-borne infection in smokeless community spaces. Smokeless residences appear to have increased the morbidity of pneumonia.