A study published in the Journal of the National Cancer Institute made headlines last year for its startling and mysterious conclusion: The incidence of colorectal cancer in young adults has increased sharply in generations born after 1950. Individuals born in the 1990s (currently age 20 to 29) are twice as likely to develop colon cancer and four times as likely to develop rectal cancer than individuals born in the 1950s were at those ages.
Unfortunately, no one has discovered why is this type of cancer is suddenly on the rise in younger adults. Cancer researchers suspect contributing factors may include changes in diet, more sedentary lifestyles, and obesity. Another theory is that cancers are simply being detected much earlier than in past decades.