People born in the United States after 1983, especially around 1996, are more likely to develop colorectal cancer at a young age than people born before them. This pattern suggests that factors affecting people born in more recent decades may be influencing cancer risk.

People born after 1950 have a higher risk of developing colorectal cancer at a young age compared to earlier generations, suggesting that factors in their early environment or lifestyle, rather than aging or medical screening, are responsible for this trend.

From 1990 to 2021, the number of colorectal cancer cases in people aged 40 to 44 rose by 59%, and the rate adjusted for population age increased by 37%, showing that this age group experienced the fastest growth in cases among young adults.

Colorectal cancer rates are rising faster in younger people in Europe than in older generations, suggesting that something in the environment or lifestyle during childhood or early life may be responsible for this trend.

Between 2005 and 2016, colorectal cancer became more common each year among people in their 30s in Europe, and these individuals were diagnosed at older ages than people in their 20s, suggesting that environmental or lifestyle factors affecting younger generations began influencing their health earlier in life.

Between 1990 and 2021, the number of new cases of colorectal cancer in people under age 45 in the United States rose by 34%, from 32.9 to 43.9 cases per 100,000 people.