The Preventability Of Cancer Due To Overweight And Obesity Assessing The Global Prevention Potential

Melina ARNOLD, International Agency for Research on Cancer (IARC), France
COLDITZ G. 3 , LEITZMANN M. 2 , SOERJOMATARAM I. 1 , BRAY F. 1 , ROMIEU I. 4

1 Section of Cancer Surveillance, International Agency for Research on Cancer (IARC), Lyon, France
2 Department of Epidemiology and Preventive Medicine, University of Regensburg, Germany
3 Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, St. Louis, USA
4 Section of Nutrition and Metabolism, Nutritional Epidemiology Group, International Agency for Research on Cancer (IARC), Lyon, France

Purpose: In 2012, nearly half a million cancer cases have been attributed to overweight and obesity. Yet, it is unclear how many of these cases could have realistically been avoided by public health efforts. In this study, we aim to assess and quantify the global prevention potential of cancer related to high body mass index (BMI).
 
Methods: Estimates of mean BMI in adults by age, sex, and country and relative risks obtained from published meta-analyses were used to calculate preventable fractions. The number and proportion of cancer cases that could have been avoided through realistic reductions in mean BMI was compared across five different prevention scenarios. This was done using more plausible counterfactual BMI distributions that have been achieved in the past, have been observed within the same world region or could be reached using public health interventions.
 
Results: Depending on the scenario, between 23% and 53% out of 481,000 estimated cancer cases attributable to overweight and obesity could have been avoided through prevention (17-56% in males, 26-54% in females), ranging up to 72% in cases occurring below age 50. Overall, the global prevention potential was greatest if countries adopted the lowest (healthy) mean BMI as observed in a neighbouring country of the same world region. Global prevention efforts to reduce mean BMI by one unit could decrease the cancer burden attributable to excess weight by 39%, translating into about 180,000 fewer cases in 2012. Different potential impacts were observed across the world regions, reflecting the different stages of the obesity epidemic.
 
Conclusions: The majority of the global cancer burden attributable to overweight and obesity is realistically avoidable through prevention efforts. Yet it seems that region-specific approaches are required to halt the obesity epidemic and its impact on cancer.

Funding Source: World Cancer Research Fund International (grant number SG 2012/619).