Cadmium absorption from smoking cigarettes: Calculation using recent findings from Japan

Consumed substances, including food, drink, and tobacco, produced in the environment are exposure sources of Cd. The object of the present study was to estimate Cd exposure and absorption amount from smoking cigarettes, one exposure source of Cd, using recent findings from Japan. The market share of cigarettes produced in foreign countries has increased in Japan, the proportion of tobacco leaves harvested in foreign countries has increased in cigarettes produced in Japan, and the percentage of smokers in Japan has changed. Therefore, obtaining the absorption value of Cd from smoking cigarettes using recent findings from Japan is significant.We collected information on (1) the concentrations of Cd in tobacco leaves by country of harvest and in cigarettes by country of production, (2) the concentrations of Cd in cigarette smoke, (3) the proportion of tobacco leaves harvested in foreign countries used in cigarettes made and sold in Japan, (4) the absorption rate of Cd in the airways for cigarette smoke, (5) the smoking rate by gender, age, and year in Japan, (6) the number of cigarettes sold in Japan by year and country of production, (7) the number of cigarettes smoked by smokers per day according to gender and age in Japan, and (8) the population size in 1998 by gender and age in Japan. The mean amount of Cd absorbed via the airways by smoking for smokers in Japan was calculated to be 0.89-1.78 μg/day from the above information. The values are not small in comparison with the amount of Cd absorbed from the digestive organs.The concentration of Cd in tobacco leaves harvested in Japan and cigarettes produced in Japan is generally higher than that of leaves harvested and cigarettes produced in foreign countries. The increase in the market share of cigarettes produced in foreign countries and sold in Japan and the increase in the proportion of tobacco leaves harvested in foreign countries used in cigarettes made and sold in Japan have decreased the amount of Cd absorbed by smoking for smokers in Japan.