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[SÃO PAULO] The number of people suffering from cancers associated with obesity or overweight — such as breast, colon and prostate tumours — is expected to double in Brazil by 2025, up from just over 15,000 for every 470,000 new cases diagnosed in 2012.
These are the conclusions of a study, published in the journal Cancer Epidemiology, which estimated the extent to which body mass index (BMI) is associated with cancer incidence in Brazil.
The results are worrisome because the prevalence of overweight and obesity is expected to increase in the coming years, according to Thomas Ong, an associate researcher at the Food Research Center in Brazil. Together with an ageing population, this is set to contribute to the increase of cancer cases in the country, he says.
The researchers used data from the Brazilian National Household Budget Survey and the National Health Survey from 2002 to 2013, looking for the distribution and prevalence of overweight and obesity among adults over 20 years of age across the country.
“People living in these regions have more access to ultra-processed foods, made in factories with industrial ingredients and additives invented by food technologists”
Leandro Fórnias Machado de Rezende
They also used data from the Brazilian National Cancer Institute and the Globocan project — a database that collects information on incidence, mortality and prevalence of major types of cancer in 184 countries worldwide — to estimate the country’s cancer incidence in 2012.
Their analysis verified that overweight or obesity are associated with a higher risk for 14 types of tumours, which together represented almost half of all cancer diagnoses in 2012.
Excess weight or obesity was linked to around 10,000 (5.2 per cent) and 5,000 (2.6 per cent) cancer cases in women and men, respectively. According to the authors, women face a higher risk as obesity prevalence has been increasing over the past few decades, affecting 25.2 per cent of women over 20 years of age in 2013.
For women, cervix, colon and breast cancer contributed most to the cases associated with overweight and obesity; while for men, being overweight or obese was mostly related to the development of colon, prostate, and liver tumours.
The researchers also found higher numbers of cancer cases linked to overweight or obesity in the country’s Southern and South-east states, which are richer and more developed.
“People living in these regions have more access to ultra-processed foods, made in factories with industrial ingredients and additives invented by food technologists,” Leandro Fórnias Machado de Rezende, from University of Sao Paulo’s School of Medicine and the study’s main author, told SciDev.Net.
“Sales of ultra-processed products increased by 103 per cent between 2000 and 2013 in Latin America. In the same period there was a sharp increase in overweight and obesity rates among adults in the region,” he points out.
Rezende argues that governmental policies regulating labelling, marketing and sales of ultra-processed products are necessary to reduce overweight and obesity and consequently mitigate the risk of cancer development.According to Ong, cancers linked to these conditions are more frequent in Brazil’s richer and more developed states because they are at the forefront of a ‘nutritional transition’: the trend of adopting eating habits characteristic of Westernized countries and associated with a higher risk for the disease.
“There is the greater consumption of foods rich in fat, sugars and salt, accompanied by lower consumption of fruits and vegetables in these regions,” he told SciDev.Net.
“However, this is a problem that is also reaching the northern and northeastern states, so obesity and cancer prevention strategies should focus on the country as a whole.”
The research in Cancer Epidemiology was supported by FAPESP, a SciDev.Net donor.