Background: Body mass index (BMI) has been constantly increasing over the last decades in most parts of the world, most notably in transitioning nations such as Brazil. High BMI (>22 kg/m2) is associated with an increased risk of 14 types of cancer. We estimated the extent to which reducing high BMI could lower cancer incidence in Brazil, nationally as well as at regional and state levels.
Methods: We calculated fractions of cancer incidence in 2012 attributable to high BMI as well as projections for attributable cases in 2025 using BMI data from representative national surveys and relative risks published in meta-analyses. Estimates of cancer incidence were retrieved from GLOBOCAN and the Brazilian National Cancer Institute.
Results: We found that 15,465 (3.8%) of all new cancer cases diagnosed in Brazil in 2012 were attributable to high BMI, with a higher burden in women (5.2%) than in men (2.6%). The cancer sites contributing most to the number of attributable cases were breast (n = 4777), corpus uteri (n = 1729), and colon (n = 681) in women, and colon (n = 1062), prostate (n = 926), and liver (n = 651) in men. The highest population attributable fractions (PAFs) for all cancers were found in the richer states of the country, located in the south (1.5% men/3.4% women) and the southeast (1.5% men/3.3% women).
Conclusions: Cancer cases attributable to high BMI will reach 29,490, which will be 4.6% of all cancers in Brazil in 2025; the extent will be greater in women (6.2% or 18,837) than in men (3.2% or 10,653). This information is a tool to support policy makers for future cancer prevention strategies in Brazil.
Keywords: Body mass index; Cancer; Epidemiology; Obesity; Population attributable fraction.
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