(Good Medical Health) – Reflecting the decades-old increase in obesity rates in the United States, a new study suggests that cancers attributed, at least in part, to excess weight are also increasing.

The researchers reported in The Lancet Public Health that rates of six of the twelve obesity-related cancers had increased in successive generations of young adults, with the largest increases seen in age groups the lowest. younger.

The new study could serve as a warning: in the coming years, if obesity epidemics persist, there could be an explosion of these fat-sensitive cancers, said the chief author of the study, Dr. Ahmedin Jemal, scientific vice president in charge of surveillance and health. research on services at the American Cancer Society.

"This discovery points to a future increased burden of obesity-related cancers among seniors and calls for action to alleviate this burden," he said in an e-mail.

The researchers analyzed data from a central database of state cancer registries, focusing on new diagnoses made between 1995 and 2014 on 30 types of cancer, of which 12 are associated with a excess weight. They had complete data from 25 states representing about two-thirds of the US population.

During this 20-year period, there were approximately 14.7 million new cases out of the 30 cancers. For at least eight cancers, including smoking-related and HIV-associated cancers, incidence rates have dropped.

But for six of the 12 cancers linked to obesity – colorectal, endometrial, gallbladder, kidney, pancreas and multiple myeloma – the incidence has increased steadily over the years, with larger increases in young adults .

The annual increase in the number of new cases of kidney cancer, for example, was 6.23% among 25- to 29-year-olds, but about 3% in the 45-49 age group. years. Similarly, the incidence of pancreatic cancer increased by 4.3% each year among 25 to 29 year olds, but by less than 1% per year among those aged 45 to 49 years.

Overall, rates of colorectal, endometrial, pancreatic and gallbladder cancers in millennia – young adults born around 1985 – were about double those of people born in the 1950s of the same age, the researchers said. .

The increase in the rate of kidney cancers has been particularly striking. Millennials were nearly five times more likely than baby boomers to develop kidney cancer.

In contrast, for all 18 non-obesity-related cancers except two, rates stabilized or decreased in younger cohorts of successive births.

Jemal hopes new discoveries will sound the alarm for doctors treating young adults. "Less than half of primary care physicians routinely evaluate body mass index despite national screening recommendations," he said. "In addition, only one-third of patients say they have been diagnosed or consulted about weight loss."

Public health measures, such as restrictions on advertising for unhealthy foods loaded with calories, could also be helpful, as well as more campaigns to promote healthy lifestyles, said Jemal.

The issue of cancer and obesity "is a very important topic because we have had an obesity crisis for several decades," said John Jakicic, professor and director of the Healthy Lifestyle Institute at the University of Pittsburgh, Pennsylvania. . "At one point, we started to see that diabetes was following the treatment of obesity. What we are seeing now is similar to some cancers. "

Cancer prevention will most likely involve "preventing anything else that could precipitate cancer," said Jakicic, who did not participate in the study. And although we do not yet know exactly how obesity could increase cancer rates, it's "extremely important" to see observational studies showing an association between the two, he noted.

SOURCE: bit.ly/2DRtGKO The Lancet Public Health, online February 4, 2019.