Obesity-Related Cancers Are Rising Markedly in Young Adults

Among young adults aged 25-49, of the 12 obesity-related cancers, 6 were shown to be rising significantly. The study was published in February 2019 in Lancet Public Health .

Of all cancers, %65 occur at age 65 and older, so cancer is generally known as a “disease of aging.” It occurs in childhood and youth too, though rarely. Rising obesity rates, however, are sounding an alarm for cancer incidence in young adulthood.

Risk factors in young adults are less understood than in older adults. The authors showed that early, prolonged exposure to carcinogens such as excess weight may affect individual cancer risk, particularly certain obesity-linked cancers.

Researchers limited analysis to diagnoses in the United States over a 20-year period (1995-1999, 2000–2004, 2005–2009, and 2010–2014, described in 4-year increments), involving 30 cancer types. Cancer rates in young adults rose significantly over time.

The selected 12 obesity-related cancers were the following (excluding meningioma):

The other 18 cancer types were relatively common in the 25-49 age group: anal, brain, central nervous system, cervical, esophageal squamous cell, gastric (non-cardia), laryngeal, lung and bronchial, oropharyngeal, prostate, testicular, bladder and vulvar cancers, Kaposi sarcoma, leukemia, lymphoma (Hodgkin and non-Hodgkin), and skin melanoma. Overall, representing 30 cancer types, 14 million cases were identified.

During 1995-2014, among young adults (aged 25-49), multiple myeloma and colorectal, uterine (womb), gallbladder, kidney, and pancreatic cancer incidence increased. Except for colorectal cancer, smaller increases were seen in older adults.

In particular, for these 6 cancers, the younger the age group, the larger the increase. For example, the average percentage change in pancreatic cancer incidence (annual new-case rate) for people aged 40 to 84 was <% 1, while moving from ages 35-39 to 25-29 it rose from % 1.3 to % 4.3. The authors noted, however, that these cancers remain more common in older than younger age groups. Of the other 18 cancers unrelated to obesity, only 2 (non-cardia gastric cancer and leukemia) increased as patient age decreased.

Related Topic:

• Adolescent Obesity Increases Pancreatic Cancer Risk 4-Fold 

The authors emphasized that these findings “the obesity epidemic may help generate hypotheses about its relationship with young-onset cancer, but do not provide evidence of a causal relationship”.