Experts are sounding the alarm as rates of 17 types of cancer in millennials and Gen X-ers have risen dramatically in recent years, a new study shows. For certain cancers, people born in 1990 face two-to-three times the risks that those born in 1955 did, according to the research published in the journal Lancet Public Health. The findings echo the recent worrying rise in young people developing colorectal cancer, but add more forms of the disease to the list of concerns.
It’s too soon to say what is driving the increase in what experts call “early onset” cancers, but they warn that it’s not just due to better screening; people are dying of these diseases at rates and ages not seen in their parents’ generations.
On average, the rates of 17 types of cancer, including pancreatic, breast and gastric cancer, have risen with each new generation since 1920, the study found. Previous ACS research had shown that rates of 11 cancers, including pancreatic, colorectal, kidney, uterine and testicular cancer, had been increasing among young adults.
While the new study doesn’t answer why this is happening, Sung and other experts have a prime suspect in their sights: obesity. Ten out of 17 of the cancers that are becoming more common over the generations have been linked to obesity, the study authors noted.
Research to suss out exactly how obesity might contribute to or cause cancer is ongoing, but there are some leading theories, Timothy Rebbeck, professor of cancer prevention at the Dana-Farber Cancer Institute, tells Yahoo Life. “When someone is obese, a lot of things change in the body, including chronic inflammation that leads to years and years worth of damage to cells and tissues in the body, which can lead to cancer,” he explains.
According to the MD Anderson Cancer Center, it may not be a person’s body mass index (BMI) directly; rather changes to insulin sensitivity and an increase in certain hormones might fuel out-of-control cell growth and, in turn, lead to cancer.
Coinciding rises in obesity and cancer rates, especially among young adults, suggest that the problem may begin in childhood or perhaps even before people are born, says Rebbeck. “That process of damage to your cells is starting earlier and earlier, so if there’s a 20-year lag from this obesity exposure and it starts at age 10, it’s in your 30s or 40s when cancer risk arises,” he hypothesizes. The timelines also suggest there may be other early life environmental exposures, including factors like antibiotic use or diet that may alter your gut bacteria, which may influence a person’s cancer risk.