Colorectal cancer (CRC) is the third most diagnosed type of cancer in both men and women in the United States and, recently, CRC incidence has been increasing in young adults. This unfortunate trend has prompted a new interest in detecting early-onset CRC (diagnosed in individuals under 50). A recent prospective study published in Gastroenterology suggests that higher vitamin D intake is associated with reduced early-onset CRC in young women.
The study analyzed data from the Nurses' Health Study II (NHS II), a long-term questionnaire-based study following over 94,000 female nurses aged 25 to 42 who provide updates on their demographic, lifestyle, and medical information on a bi-yearly basis. The research team identified 111 cases of early-onset CRC and 3,317 serrated polyps, a known precursor of CRC, in the NHS II cohort.
The median vitamin D intake was 372 IU/day. Women under 50 with higher vitamin D intake tended to exhibit lower BMI, be more likely to be physically active, and have a healthy dietary pattern than counterparts with lower Vitamin D intake. High vitamin D was also associated with reduced alcohol and cigarette use, consumption of red meat, and increased use of aspirin and multivitamins.
The study accessed both dietary and supplemental vitamin D intake. Although both sources were inversely associated with early-onset CRC, dietary vitamin D, primarily acquired from dairy products, was associated with a lower risk of developing early-onset CRC. The study demonstrated a similar association with serrated polyps.
While the investigators note limitations of the study, including the low number of cases, they conclude that higher total vitamin D intake is associated with decreased risks of early-onset CRC and its precursors. They also suggest that preventing vitamin D deficiency is very important for young women, particularly those at high risk of developing CRC. Finally, the authors indicate that these findings could lead to a new, inexpensive, low-risk strategy for CRC prevention in young women.