Millennials born after 1990 face nearly double the risk of contracting colon cancer and quadruple the risk of rectal cancer compared to people born in 1950, a new study shows.
The Journal of the National Cancer Institute published a study Tuesday showing that after risks had decreased previously, the rate of colon cancer increased 1 to 2 percent a year since the mid-1980s for the 20 to 39 age group. Rectal cancers have increased more than 3 percent since 1974 for adults 20-29.
Rates are also increasing, though less rapidly, for adults ages 40-54, while they are declining for those over 55, the study showed.
The study may prompt doctors to begin screening patients at younger ages; current recommendations start at age 50, with screenings at younger ages for those with a family history of the disease.
Although no definitive reason for the increased cancer risk for millennials was given, study leader Rebecca Siegel of the American Cancer Society said changes in diet, a sedentary lifestyle, being overweight, and low fiber consumption may be causing the rapid increase. HPV, which can cause anal cancer, was ruled out as a factor because it causes squamous cell cancers different from the intestinal polyps that characterize colorectal cancers, The Washington Post reported.
Siegel called the study results “just very shocking,” saying researchers had not expected the rates to rise so rapidly, the Post reported.
The study looked at 490,000 people and compared incidences of cancer in five-year periods by looking at years of birth and focusing on five-year age groups to determine cancer rates and risks.