The incidence of early-onset colorectal cancer has been rising in high-income countries for 20 years. At the same time, the consumption of sugar-sweetened beverages, which can have adverse metabolic effects throughout life, has risen among successive birth cohorts. As part of the large, prospective Nurses' Health Study II (NHSII), researchers investigated the association between the intake of sweetened beverages-particularly those sweetened with sugar-in adulthood and adolescence and the risk of early-onset colorectal cancer.

The NHSII included 116,429 female RNs who were 25 to 42 years old when enrolled in 1989. Of these, 95,464 who reported adulthood beverage intake were included in the final analysis of this study. A subset of 41,272 participants reported beverage intake from 13 to 18 years of age.

During 24 years of follow-up, 109 cases of early-onset colorectal cancer were documented. Compared with women who consumed less than one serving per week of sugar-sweetened beverages in adulthood, those who consumed two or more servings per day had a 2.2-fold increased risk of early-onset colorectal cancer, with a 16% higher risk for each additional serving per day. No associations were found for artificially sweetened beverages or fruit juices. Each serving per day increment of sugar-sweetened beverages from 13 to 18 years of age was associated with a 32% higher risk of early-onset colorectal cancer. Replacing sugar-sweetened beverages with coffee or milk or reduced-fat milk in adulthood was associated with a reduced risk of early-onset colorectal cancer.

In addition to possible unmeasured confounding factors, other limitations of the study were that it included mostly White female nurses, and the findings may not be generalizable to other racial and ethnic groups.