Obesity Linked to Numerous Cancers

Obesity increases the risk of cancer.

The increased risks of diabetes and heart disease aren’t the only reasons to lose weight. New research has been finding that at least twenty types of cancers are associated with being overweight or obese.

Large European cancer study

In one – a large new European study from Germany’s University of Kiel’s Department of Epidemiology – researchers found liver and gallbladder cancer significantly linked to obesity and being overweight. The researchers studied a population of 359,525 European men and women. They collected data on each person’s weight, body mass index, waist and hip circumference, waist-to-hip and waist-to-height ratio, and weight change during adulthood. They cross-referenced this data with the incidence of both liver cancer and gallbladder cancer.

After a follow-up period of nearly nine years, the study found that all of the measures of obesity and increased weight were linked to an increase in liver and gallbladder cancers. Some of the strongest associations included the waist-to-hip and waist-to-height ratio, which was associated with over triple the risk of liver cancer. Weight gain during adulthood was associated with two-and-a-half times the risk of liver cancer.

The researchers concluded that their results “provide evidence of an association between obesity, particularly abdominal obesity, and risk of hepatocellular carcinoma and gallbladder cancer.”

Over 20 cancers linked to obesity

This confirms a recent finding from China Medical University’s Department of Gastroenterology that gallbladder cancer and over 20 other types of cancer are significantly linked with being obese and/or overweight.

Another recent study, this one published in May’s Cancer Causes Control Journal, found that cancers of the cervix, endometrium, gallbladder, lip, mouth, pharynx, liver, lung, ovaries, pancreas, stomach, and thyroid were related to obesity among Pacific Islanders in New Zealand.

To this we can add a study published last fall from Germany’s Cancer Research Center in Heidelberg. The researchers tracked 30,020 patients who had been hospitalized since 1964, and monitored their cancer incidence through 2006.

They found that obesity increased the risk of twelve cancers. Among the highest correlations, obesity increased the risk of nervous system cancer (hemangioma) by over 13 times, increased the risk of male genital cancer by nearly four times, increased the risk of intestinal cancer by almost three times, increased the risk of kidney cancer by 2-1/2 times, and increased the risk of endometrial cancer by over two times (232%).

The average increased risk was 20% among the whole population. The researchers also documented that “at least 20 different cancers” were also associated with obesity.

In 2010, researchers from the Washington University School of Medicine found that increased weight, weight gain, and obesity accounts for about one-fifth of all cancer cases. They found that obesity is related to esophageal cancer, thyroid cancer, colon cancer, renal cancer, liver cancer, melanoma cancer, multiple myeloma cancer, rectum cancer, gallbladder cancer, leukemia cancer, lymphoma cancer, prostate cancer, postmenopausal breast cancer and endometrial cancer.

“The burden of obesity on society continues to increase and warrants closer attention by clinicians for both cancer prevention and improved outcomes after diagnosis,” they concluded.

Oxford University researchers found that as body mass index increases, incidences of adenocarcinoma, colon cancer, post-menopausal breast cancer, endometrial cancer and kidney cancer all increase exponentially. They also found that gallbladder cancer, malignant melanoma, ovary cancers, thyroid cancers, non-Hodgkin lymphoma, multiple myeloma and leukemia incidence also increase among the overweight and obese.

Obesity is also linked to vitamin D deficiency. This may provide at least one causal link. Another is that environmental toxins are linked to obesity as well as cancer.

Researchers from Israel’s Sheba Medical Center found that the potential mechanisms for the obesity-cancer connection included increased intake of “potentially carcinogenic food,” excessive calories, less exercise (shown to reduce cancer risk) and the release of “carcinogenic factors” from adipose tissue mass. Other researchers have proposed metabolic associations between glucose and insulin metabolism among those who are obese and/or overweight.