Alternative for estimating the burden of lung cancer from occupational exposures - some calculations based on data from Swedish men

Objectives This study attempts to demonstrate a calculation of the occupational lung cancer burden using economically active men in Sweden as an example. Methods Estimates were calculated using Swedish register data on occupation in 1970, lung cancer incidence in 1971-1989, smoking frequencies in 1963, and the formula I-0 = RI0F + I-0(1-F), where I-0 is the overall incidence, R is the relative risk associated with a factor (here smoking), F is the fraction of persons at risk (smokers), and I is the incidence among those not at risk (nonsmokers). Results Farmers, gardeners, forestry workers, and fishermen had the lowest lung cancer risk (42.1 per 100000 person-years) and a smoking frequency of 44.7%. Their I-0 was 12.6 or 8.4 per 100 000 person-years, taking R for smoking as 6 or 10, respectively. From these I-0 estimates, the expected rates for white- and blue-collar workers (smoking frequencies 52.7 and 57.7%, respectively) were 45.8 and 49.1 per 100 000 person-years, as compared with the 22% and 57% higher observed rates, respectively. Weighing these excesses proportionally according to the sizes of the three occupational categories gave, respectively for R equal to 6 and 10, occupation-related excesses of 39% and 32% and population-attributable risks of 28% and 24%. Conclusions About one-fourth of the lung cancers that occur among economically active Swedish men seem to have been related to occupation. This figure agrees with estimates made by other methods in Nordic countries. Due to interaction, the population-attributable risk from smoking is still high, 73% and 83% at relative risk values of 6 and 10, respectively.