Analysis of cancer risk related to longitudinal information on smoking habits.

Radiation Effects Research Foundation (RERF) has followed the RERF Life Span Study (LSS) cohort consisting of atomic bomb survivors and unexposed subjects for more than 40 years. The information on their lifestyles, including smoking habits, has been collected in the past 25 years through two mail surveys of the entire LSS cohort and three interview surveys of a subcohort for the biennial medical examination program. In the present study an attempt was made to consolidate the information of smoking habits obtained from the five serial surveys, and then a risk analysis was conducted to evaluate the effect of updating the smoking information on the smoking-related risk estimates for lung cancer. The estimates of smoking-related risk became larger and estimates of dose-response became sharper by updating smoking information using all of the data obtained from the five serial surveys. Analyses were also conducted for cancer sites other than lung. The differences in risk estimates between the two approaches were not as evident for the other cancer sites as for lung.