Approximately 5.6% of all incident cancers in 2012 were attributable to the combined effects of diabetes and high BMI as independent risk factors, according to a new analysis published in The Lancet Diabetes & Endocrinology.
In a comprehensive global analysis of cancer incidence and published literature assessing the associations of diabetes and high BMI with site-specific cancers, the researchers also found that BMI of at least 25 kg/m² was responsible for twice as many cancer cases as diabetes (544,300 vs. 280,100 cases).
“As the prevalence of these cancer risk factors increases, clinical and public health efforts should focus on identifying preventive and screening measures for populations and for individual patients,” Jonathan Pearson-Stuttard, BMBCh, honorary clinical research fellow at the School of Public Health at Imperial College London, United Kingdom, said in a press release. “It is important that effective food policies are implemented to tackle the rising prevalence of diabetes, high BMI and the diseases related to these risk factors.”
Pearson-Stuttard and colleagues estimated population attributable fractions for 12 cancers by age and sex for 175 countries in 2012. Researchers used comprehensive prevalence estimates for diabetes and BMI categories in 2002, assuming a 10-year lag between exposure to diabetes or high BMI (defined as BMI 25 kg/m²) and incidence of cancer, combined with RRs from published estimates, to quantify the contribution of diabetes and high BMI to site-specific cancers, both individually and combined as independent risk factors. Researchers also used a conservative model assuming a full overlap of the risk from diabetes and high BMI. The researchers also used GLOBOCAN 2012 cancer incidence data to estimate the number of cancer cases attributable to the two risk factors, and estimated the number of cancer cases in 2012 attributable to increases in the prevalence of diabetes and high BMI from 1980 to 2002. All analyses were done at the individual country level and grouped by region.
Researchers found that 5.6% of all incident cancers in 2012 reported by GLOBOCAN were attributable to the combined effects of diabetes and high BMI as independent risk factors, corresponding to 792,600 new cases. Additionally, diabetes and high BMI contributed to 24.5% of the 766,000 cases of liver cancer and 38.4% of the 317,000 cases of endometrial cancer worldwide, and cancer cases attributable to diabetes and high BMI were nearly twice as common in women as men (496,700 vs. 295,900).
Globally, 38.2% of cancer cases attributable to diabetes and high BMI in 2012 occurred in high-income, Western countries, according to researchers, whereas 24.1% of such cancers occurred in East Asia and Southeast Asia.
“At the two extremes, just 7% of cancer cases in 2012 attributable to diabetes were due to increased diabetes prevalence in women in central and eastern Europe, compared with 48% in men in south Asia,” the researchers wrote.
In the conservative estimate, about 4.5%, or 626,900 new cases of all incident cancers assessed, were attributable to diabetes and high BMI combined. From 1980 to 2002, 26.1% of diabetes-related cancers (77,000 new cases) and 31.9% of high BMI-related cancers (174,040 new cases) were attributable to increases in the prevalence of these risk factors, according to researchers.
“Increases in diabetes and high BMI worldwide could lead to a substantial increase in the proportion of cancers attributable to these risk factors, if nothing is done to reduce them,” Pearson-Stuttard said in the release. “These projections are particularly alarming when considering the high and increasing cost of cancer and metabolic diseases, and highlight the need to improve control measures and increase awareness of the link between cancer, diabetes and high BMI.” – by Regina Schaffer
Disclosure: One of the study authors reports he received a charitable grant from the Young Health Program of AstraZeneca and personal fees from Third Bridge, Prudential and Scor.