Feasibility of a prospective study of smoking and mortality in Qidong, China.

Qidong is a rural county in eastern China with particularly good facilities for epidemiological research: cigarette use by adult males is widespread (70% now smoke), male lung cancer rates already appear to be rising, the population is stable and well served by a county-wide network of health care facilities, and systematic county-wide registration of all deaths has existed since the mid-1970s, causes currently being assigned according to the 9th International Classification of Diseases.