A recent study led by epidemiologist Hermann Brenner of the German Cancer Research Center (DKFZ) reveals that being overweight or obese poses a greater risk for developing several cancers than previously understood. The research indicates that up to 11.5% of cancer cases may be attributable to excess body weight, nearly doubling earlier estimates that ranged between 2% and 8%.
The findings underscore the importance of abdominal fat in cancer risk and suggest efforts to prevent obesity could have a more significant impact on cancer prevention than once thought.
Beyond Body Mass Index: Measuring Abdominal Fat
Previous studies mainly relied on body mass index (BMI) to assess obesity-related cancer risks. However, BMI does not distinguish between fat and muscle mass or reflect fat distribution, which is critical because fat accumulation around the abdomen behaves differently than fat elsewhere.
Abdominal fat triggers a chronic inflammatory metabolic state by releasing signaling molecules called adipokines. These substances circulate through the bloodstream and influence processes such as cell growth, division, and inhibition of programmed cell death — all mechanisms that can promote tumor formation and growth.
To reflect this, the DKFZ team incorporated measurements of waist circumference and waist-to-hip ratio along with BMI. They analyzed health data from 458,543 participants in the UK Biobank, tracking them for an average of 12 years and documenting 50,000 new cancer cases.
Addressing Previous Underestimations
The researchers also addressed potential biases in earlier studies by excluding cancer cases occurring within the first seven years after participants enrolled. This approach helped avoid skewed results due to weight loss caused by developing cancer before diagnosis, which could mask the true relationship between obesity and cancer risk.
Gender Differences and Hormone-Dependent Cancers
The study found that overweight women might face a higher proportion of obesity-related cancers compared to men, although additional research is needed to confirm this. Hormone-dependent cancers such as breast, uterine, and ovarian cancers, which are influenced by estrogen levels, appear to be particularly linked to excess abdominal fat, which can elevate estrogen in the body.
Implications for Cancer Prevention
While obesity’s connection to cardiovascular disease and diabetes is widely recognized, this study highlights the need to emphasize its role in cancer risk. According to Michael Leitzmann, an epidemiologist not involved in the study, preventing obesity could contribute significantly to reducing cancer incidence. He views the findings as encouraging, suggesting that controlling body weight may enhance cancer prevention efforts more than previously assumed.
