Changing Urbanization Patterns in US Lung Cancer Mortality, 1950–2007

Abstract

This study examined disparities in lung cancer mortality rates among US men and women in metropolitan and non-metropolitan areas from 1950 through 2007. Annual age-adjusted mortality rates were calculated for men and women in metropolitan and non-metropolitan areas, and differences in mortality rates were tested for statistical significance. Log-linear regression was used to model annual rates of change in mortality over time, while Poisson regression was used to estimate relative risk after adjusting for age, sex, deprivation, and urbanization levels. Urbanization patterns in lung cancer mortality changed dramatically between 1950 and 2007. Compared to men in metropolitan areas, men aged 25–64 years in non-metropolitan areas had significantly lower lung cancer mortality rates from 1950 to 1977 and men aged ≥65 years in non-metropolitan areas had lower mortality rates from 1950 to 1985. Differentials began to reverse and widen by the mid-1980s for men and by the mid-1990s for younger women. In 2007, compared to their metropolitan counterparts, men aged 25–64 and ≥65 years in non-metropolitan areas had 49 and 19% higher lung cancer mortality and women aged 25–64 and ≥65 years in non-metropolitan areas had 32 and 4% higher lung cancer mortality, respectively. Although adjustment for deprivation levels reduced excess lung cancer mortality risk among those in non-metropolitan areas, significant rural–urban differences remained. Rural–urban patterns reversed because of faster and earlier reductions in lung cancer mortality among men and women in metropolitan areas. Temporal trends in rural–urban disparities in lung cancer mortality appear to be consistent with those in smoking.