Being overweight carries several health risks, with one of the most worrying being an increased likelihood of cancer. In fact, 40 percent of all cancers in the U.S. are now linked to excess weight.
Carrying excess weight is now associated with a higher risk for 13 types of cancer, including breast, ovarian, thyroid and liver cancer — the second deadliest form of cancer.
Even though studies have linked excess weight to specific types of cancers, there haven’t been any statistics showing just how many cases of a particular type of cancer can be associated with being overweight or obese.
But one country has done the numbers where thyroid cancer is concerned, and they don’t look good for those who carry excess weight — especially men who see their risks surpassing a disease that typically is 2.9-times more common in women…
Excess weight contributes to thyroid cancers
According to a recent study, one in five future thyroid cancer cases in Australia can be linked to being overweight or obese.
“This finding translates to close to 10,000 thyroid cancers in the next 10 years,” says study lead Dr. Maarit Laaksonen, a senior lecturer in data science at UNSW. “Obesity explains 75 percent of this burden in Australia.”
This is worrying since the obesity rate in Australia has doubled over the last two decades. About 75 percent of Australian men and 60 percent of Australian women are now classified as either overweight or obese.
The U.S. is in the same fix. An estimated 43 percent of U.S. adults are obese, with another 31 percent coming in as overweight. That means almost three-quarters of Americans are carrying excess weight and are likely facing the same advanced risk for thyroid cancer.
According to the World Health Organization’s International Agency for Research on Cancer, being overweight is a risk factor for a number of different cancers, including thyroid cancer. Therefore, preventing obesity and excess weight gain should be a priority for thyroid cancer prevention.
The UNSW-led study is the first to evaluate the thyroid cancer burden in relation to current levels of overweight and obese adults. It also is the first to break down and compare this burden by sex.
By doing this, the study discovered that being overweight or obese explains two in five thyroid cancer cases in men, compared with only one in 10 cases in women. This is interesting because thyroid cancer normally is two to three times as common in women as in men.
“It is still not well understood what causes the sex difference in overweight/obesity-related thyroid cancer risk,” Laaksonen says. “But our findings add evidence to the urgent need to halt and reverse the current global trend in weight gain, especially obesity and especially in men.”
More research is needed to determine precisely what might be causing the remaining four in five thyroid cancers not related to weight. Some other factors known to increase thyroid cancer risk include iodine deficiency, exposure to ionizing radiation, and genetic factors and family history.
“Thyroid cancer is a bit like prostate cancer that its risk factors are not yet very well understood,” Laaksonen says.
Laaksonen has previously studied preventable lung, colorectal, breast, endometrial, ovarian, pancreatic, kidney, bladder and head and neck cancers. She plans to conduct a study on the preventable burden of stomach and esophageal cancers, as well as a summary paper on preventable cancer burden in Australia across all cancers.
How being overweight impacts cancer risk
While the exact mechanism has yet to be found, we do know excess body weight can affect cancer risk in several ways. Being overweight can increase inflammation and impair immune system function. It can also wreak havoc with certain hormone levels such as insulin and estrogen, as well as factors that regulate cell growth and proteins that influence how your body uses certain hormones.
Obviously, the best way to reduce your risk of thyroid and other cancers is to lose weight. Even losing 5 percent of your body weight can help reduce inflammation markers and in turn lower your cancer risk.
It can be tempting to look for a quick and easy weight loss solution. But for shedding weight and keeping it off over the long term, it’s best to stick to the tried-and-true formula of eating a healthy diet and getting plenty of exercise.
A good meal plan to follow for weight management is the Mediterranean diet — particularly its “green” form, which eliminates red meat, emphasizes plenty of fruits and vegetables and includes green tea and plant-based protein.
Previous research has also found that the keto diet can help men lose weight and balance their hormones.
Sources:
One in five future thyroid cancers linked to excess weight — UNSW Sydney
Key Statistics for Thyroid Cancer — American Cancer Society
Prevalence of Overweight, Obesity, and Severe Obesity Among Adults Aged 20 and Over: United States, 1960–1962 Through 2017–2018 — Centers for Disease Control and Prevention
IARC identifies eight additional cancer sites linked to overweight and obesity — International Agency for Research on Cancer