Today's lifestyles, tomorrow's cancers: trends in lifestyle risk factors for cancer in low- and middle-income countries

Background: The global burden of cancer is projected to increase from 13.3 to 21.4 million incident cases between 2010 and 2030 due to demographic changes alone, dominated by a growing burden in low-and middle-income countries (LMICs). Lifestyle risk factors for cancer are also changing in these countries and may further influence this burden. Design: We consider examples of changes already occurring in population-level distributions of tobacco and alcohol consumption, body weight, and reproductive lives of women to gauge the magnitude of their projected impact on cancer incidence in future decades. Results: Trends in lifestyle factors vary greatly between settings and by sex. Some common trends point to considerable increases in cancers of the (i) lung in men due to tobacco smoking; (ii) upper aerodigestive tract (UADT) due to increasing tobacco and alcohol consumption, worse in men; (iii) colon from increasing body mass index, and alcohol and tobacco consumption; and (iv) in women, breast due particularly to consistent international trends of younger age at menarche, smaller family size, and, at postmenopausal ages, increasing body weight. Conclusions: In many LMICs, the future cancer burden will be worsened by changing lifestyles. Affected common cancer sites likely to experience the largest increases are lung, colon, UADT, and breast.