Comparing medical expenditures of smokers and nonsmokers in studies using direct methodology in Japan.

Numerous epidemiologic studies have revealed that smoking is a significant risk factor of many diseases. Some studies reported increase in medical expenditure by smoking using odds or hazard ratios between smoking and diseases in epidemiologic studies. The purpose of the present study is to investigate the ratios of mean medical expenditures between smokers and nonsmokers from studies conducted observing medical expenditure directly in Japan. We collected 11 published articles of studies conducted observing medical expenditures of smokers and nonsmokers directly in Japan. The weighted geometric mean of ratios between age-adjusted mean medical expenditures for smokers and nonsmokers of National Health Insurance and Government-Managed Health Insurance beneficiaries which included many elderly individuals was somewhat greater than 1.0, while the value of Society-Managed Health Insurance that included a small number of elderly people was less than 1.0. Smoking and smokers' indifference to health increase the medical expenditure of the smokers, especially elderly smokers. It was not determined, however, whether the mean medical expenditure of smokers is actually greater than that of nonsmokers.