A dramatic rise in several types of cancer is linked to obesity among young adults

Recently published research reports that the incidence of 17 different types of cancer is higher among younger millennials than among older generations. The majority of these rising cancers are directly linked to obesity, demonstrating how excess weight significantly undermines the health of young adults.

Cancer is a disease caused by defective genes that accumulate during aging and it is for this reason that the incidence of cancer increases significantly with age. For example, while we observe about 250 cases of cancer per 100,000 people aged 40-45, this number explodes to almost 2,500 cases per 100,000 between 75-80 years of age, or 10 times more .

However, in most cases lifestyle has a strong influence on these procancer genes: obesity, smoking, a sedentary lifestyle and bad eating habits (too much meat and ultra-processed products, not enough plants) are all characteristics that create physiological conditions favorable to it. the development of cancer and which greatly accelerates the risk that the disease will develop prematurely, sometimes even from an early age. In other words, even if the risk of cancer is generally lower in young people, youth is not an infallible weapon against the disease if the body is under conditions that helpful for the appearance and progression of cancer cells.

Early cancers

This is clearly illustrated by a recent study that compared the incidence of 34 different cancers between millennials (born in 1990) and those affected by previous generations (1).

To compare cancer rates between generations, researchers calculated incidence and mortality rates specific to each birth cohort, separated by five-year intervals, from 1920 to 1990. The data were adjusted for the effect of age as well as the time in which people lived (to take into account medical advances and the increase in life expectancy).

The researchers found that the incidence rates of 8 cancers increased with each successive birth cohort born since 1920. This is particularly striking for the 1990 birth cohort (the millennials) who have an incidence rate of two to three times higher for pancreas, kidney cancers. and small intestine than in the 1955 birth cohort. They also noted that the rates of 9 cancers (including breast, uterus and colon) were increasing in cohorts younger, while these cancers decreased in older groups.

Therefore the increase in the number of cancers in recent generations indicates that these people were exposed very early in life to conditions that accelerate the appearance of cancer cells and/or their progression to adult cancer .

Cancers associated with excess weight

The excess weight of these young people is one of the most important factors involved, as 10 of the 17 cancers whose incidence is increasing in younger birth cohorts are obesity-related cancers (colorectal, kidney, gallbladder, uterus, pancreas, stomach, ER+ breast, ovary, myeloma, liver). This is very surprising for uterine (endometrial) cancer, the one most closely related to obesity: compared to older groups, the incidence rate of this cancer increased by 169% in the group born in 1990. This is consistent with a recent study. showed that excess body weight in early life (ages 18 to 40) was associated with an increased risk of 18 types of cancer (2).

These generational changes in cancer risk are a clear indication that today’s lifestyle, characterized by a high consumption of ultra-processed foods, a sedentary lifestyle and obesity, is completely un- compatible with maintaining good health. The fight against obesity should be a national priority, as was the fight against tobacco; the health of future generations and the survival of our health system are at stake.

(1) Sung He et al. Differences in cancer rates among adults born between 1920 and 1990 in the US: an analysis of population-based cancer registry data. Lancet Public Health; 2024; 9:e583.

(2) Recall of M et coll. Longitudinal body mass index and cancer risk: a cohort study of 2.6 million Catalan adults. Nat. Association. 2023; 14: 3816.