Obesity is the main cause behind over a half a million new cancer cases worldwide each year -with the problem being particularly serious in North America -a new report by the World Health Organization’s cancer research agency revealed.
This means that about 3.6% of all cancers worldwide and two-thirds of overweight-related cancers can be found in North America and Europe, WHO said.
The report, which was published in the medical journalLancet Oncology, gathered its information from 184 countries.
The WHO’s International Agency for Research on Cancer (IARC) added that high body mass index (BMI) – a person’s weight in kilograms divided by the square of their height in meters – has now become the main signifier of cancer risk. BMI has become the standard in determining whether someone is at a healthy body weight.
Scientists hypothesize that obesity and being overweight trigger cancer by changing insulin, glucose and hormone levels, and increasing chronic inflammation. This is believed to be more common and likely to occur in women’s bodies.
Dr. Melina Arnold, the study’s lead researcher of the International Agency for Research on Cancer said during an interview with CBC News:
“For women, we know there’s more cancer sites that are related to obesity, such as post-menopausal breast cancer but also breast cancer and cancer of the womb. So, those are very common cancers that are only affecting women. That’s why we found this higher burden.”
She also added in a journal news release:
“Our findings add support for a global effort to address the rising trends in obesity. The global prevalence of obesity in adults has doubled since 1980. If this trend continues, it will certainly boost the future burden of cancer, particularly in South America and North Africa, where the largest increases in the rate of obesity have been seen over the last 30 years.”
The study mainly focused on the ‘number of cancers caused by obesity’ including cancers of the oesophagus, colon, rectum, kidney, pancreas, gallbladder, postmenopausal breast, ovary and endometrium. The rates of obesity-related cancers were different from one country to another.
The results also showed that it’s not only economic dependence that contributes to why more and more people are becoming obese, but also corresponded to the human development index (HDI). That’s why North America leads the ratings with the worst cancer problem caused by obesity: almost a quarter of global cancer cases associated with high BMI, or 111,000 obesity-related cancers diagnosed in 2012.
Christopher Wild, IARC’s director claimed that the results emphasized the importance of helping people maintain a healthy weight to reduce their risk of developing a diversified amount of cancers, and of helping developing countries avoid the problems currently faced by wealthier ones. He said:
“The number of cancers linked to obesity and overweight is expected to rise globally along with economic development.”
According to the study:
“Among men, rates were particularly high in the Czech Republic (5.5% of new cancer cases in 2012), Jordan and Argentina (4.5%), and the U.K. and Malta (4.4%). Among women, rates were highest in Barbados (12.7%), Czech Republic (12%), and Puerto Rico (11.6%).”
Meanwhile, rates were lowest in the countries of sub-Saharan Africa, not surprisingly, with less than 2% in men and less than 4% in women.
Moreover:
- Approximately 65,000 cases were recorded in Europe
- A mortality rate of 50,000 in China
- 6,000 cancer cases per year in Canada
Dr. Benjamin Cairns, from the University of Oxford in the U.K., wrote in an accompanying editorial:
“If 3.6 percent of all cancers are associated with [overweight and obesity], that is nearly half a million cancers, but this number is large mainly because the world population is large. Global health resources specifically for cancer prevention are not so large, and the resources targeted at obesity must be balanced against those for other important causes of cancer, particularly infections and tobacco use, which are each associated with much larger proportions of cases.”
Dr. Darren Brenner, who works with Alberta Health Services and is not linked to the Lancet Oncology-published study, talked about Canadian cases after she also studied the link between obesity and cancer:
“In Canada, that works out to be about 6,000 cancer cases per year that are attributable to excess body weight. So when we think about it in those absolute terms, I think it’s very very important that people take these results seriously.”
