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.