by Kanae Kondo, Ichizo Morita, Shigemitsu Sakuma, Isao Ohsawa Objectives This study aimed to longitudinally examine nationwide changes in smoking behavior among the Japanese population in response to the COVID-19 pandemic. Design and setting A secondary analysis was conducted using cigarette sales data from the Tobacco Institute of Japan, monthly tobacco expenditures from the Family Income and Expenditure Survey conducted by the Ministry of Internal Affairs and Communications, and smoking prevalences from the National Database of Open Data Japan.
An interrupted time-series segmented regression model adjusted for seasonality and autocorrelation was used to examine changes in cigarette sales and monthly tobacco expenditures before and after the first declaration of a state of emergency. Participants Depending on the data source, data from 2014 to 2022, from 2015 to 2025, or from 2015 to February 2026 were used.
Primary and secondary outcome measures Changes in level and slope were evaluated before and after the first state of emergency and after COVID-19 was downgraded to a common infectious disease.
PLOS ONE (Medicine) published a clinical update in Research Highlights on 05 Jun 2026.
The item focuses on Changes in tobacco sales before, during, and after the COVID-19 pandemic in Japan: An interrupted time series analysis.
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