Cancer Risk Increases as Waist Circumference and Waist-to-Hip Ratio Increase

Worldwide, over the past 40 years, the proportion of overweight and obese adults has increased more than 2-fold. Similar increases in obesity are observed in children and adolescents. When we consider the environmental factors causing cancer, we see that obesity is now the 2nd most important cause after smoking. Research even predicts that obesity will overtake smoking in 2020 to become the leading cause of cancer.

Recently, one of the important British scientific publications, British Journal of Cancer , published a meta-analysis emphasizing the importance of lifestyle. General obesity was compared with regional fat accumulation (particularly around the abdomen) in terms of increased cancer risk, and it was argued that excessive fat accumulation around the abdomen may be at least as important as general obesity.

Could Waist Circumference Be a Cancer Risk Independent of Obesity?

In 7 different European countries, among more than 43 thousand people followed for an average of 12 years, 1656 obesity-related cancer cases occurred. Among these cancers, those associated with obesity and excess weight [postmenopausal breast cancer (the period after menopause in women), colorectal, lower esophageal, upper stomach (the part joining the esophagus), liver, gallbladder, pancreatic, uterine, ovarian and kidney cancers] were examined. In the study, each proportional risk model of obesity indicators (body mass index BMI, waist circumference, hip circumference and waist-to-hip circumference) was analyzed as a separate variable.

The Relationship Between Obesity, Regional Fat Accumulation and Cancer

According to the research, for measuring general obesity, body mass index (BMI) increases were observed in all 10 obesity-related cancer types to raise overall risk by up to %11. Similarly, with regional fat accumulation, increased waist circumference (WR) raised risk by up to %13, and the waist-to-hip ratio (WHR) by up to % 15, demonstrating that these markers contribute toward cancer in the obesity–cancer relationship.

Furthermore, excessive regional fat accumulation (around the abdomen) was observed to be more closely associated particularly with colorectal cancer (%15-21) and breast cancer in postmenopausal women (on average %20).

This research can be considered valuable for showing that obesity is not simply an increase in body weight and illustrating how excessive regional fat accumulation and changes in body shape can increase cancer risk. It is also important for emphasizing that cancer risk can be reduced through positive lifestyle habits. However, to identify the underlying biological reasons and obtain more detailed analyses, more research is needed on this subject than the studies conducted on the relationship between BMI and cancer.