Obesity Linked to Increased Cancer Risk in Young Adults

Childhood obesity may have lasting effects that could permanently alter the likelihood of developing cancer.

Young adults with a history of obesity may be more likely to develop cancers typically associated with older adults, according to a recent review published in Obesity.

A researcher from Case Western Reserve University School of Medicine compiled evidence from more than 100 publications that suggests obesity elevates the risk of 13 different cancers in young adults. According to the data, cancer rates in younger adults are rising in tandem with obesity rates, indicating that childhood obesity may have lasting health effects. The review analyzes 13 cancers previously identified by the International Agency for Research on Cancer as linked to excess body fat and specifically addresses how obesity promotes the progression of these cancers.

Obesity causes changes, such as epigenetic modifications, to an individual’s DNA that can add up over time and increase cancer risk, even if weight loss occurs.

“If you are obese, you are at a higher risk of cancer,” study author Nathan A. Berger, MD, said in a press release. “If you lose weight, it improves the prognosis and may lower your risk, but it never goes away completely.”

According to Berger, data from clinical trials and animal obesity studies indicate that obesity accelerates cancer progression in a number of ways. For example, it overactivates the immune system to produce harmful byproducts such as peroxide and oxygen radicals that mutate DNA. Additionally, obesity alters individuals’ metabolism, causing growth factor and hormone imbalances that allow cancer cells to thrive. Obesity-induced gut changes and acid reflux can also lead to heightened risk of cancers.

“Even if one pathway is successfully blocked, obesity-induced cancer takes another path,” Berger said.

In one study of more than 1.1 million Israeli men tracked over time, overweight adolescents aged 16 to 19 years had a 1.5-fold increased risk of developing colon cancer by age 48, Berger cited. In another study, anecdotal evidence suggested long-term effects of childhood obesity on higher cancer incidence, which is further supported by analyses indicating that adults with a history of obesity are twice as likely to develop multiple myeloma. According to Berger, obesity can also shorten cancer timelines by shrinking the period between benign and malignant cancer progression.

Health care providers should document health data, such as body mass index, throughout a patient’s life to help determine overall risk. Because most patients with cancer present after significant weight loss, physicians may overlook obesity-related factors, Berger noted. However, the increased use of electronic medical records can help establish databases to detect weight loss patterns.

“By documenting characteristics like diet and environment of an obese person, we might be able to get an indication of a possible prognosis,” he said.

Health care providers can use this information to identify potential risks and provide effective interventions, such as early cancer screening in young adults.

However, Berger concluded that “the most effective way to curtail development of this problem is to prevent the expansion of the obesity pandemic in both children and adults.”

Reference

Obesity is Shifting Cancer to Young Adults [news release]. Case Western Reserve University’s website. http://casemed.case.edu/cwrumed360/news-releases/release.cfm?news_id=1107&news_category=8. Accessed March 28, 2018.