Oct. 11 (UPI) -- With colorectal cancer deaths rising among women younger than 50, a study found obesity was associated with mortality from the disease.
Researchers found obesity -- a body mass index of 30 or above -- was linked to the highest risk of colon and rectal cancer. The findings were published Thursday in JAMA Oncology.
"Given that most of these younger case are diagnosed symptomatically with more advanced tumors and with a significant influence on years of life lost, our findings reinforce the benefits of maintaining a healthy weight throughout life," the researchers wrote in the study. "Our findings suggest the promise of using body weight to personalize and complement early cancer screening strategies among adults younger than 50 years."
Colorectal cancer is the third most common cancer among both sexes in the United States, according to the Centers for Disease Control and Prevention, but men are diagnosed with the disease more often -- there are 43.5 cases per 100,000 men compared with 33.3 cases per 100,000 women.
Overall, the rates of colorectal cancer incidence and mortality have decreased by more than 45 percent since 1980, mainly because of greater screening uptake among average-risk adults, typically starting at 50 years of age, and favorable changes in some lifestyle risk factors, the authors noted.
But incidence and mortality have been increasing among all age groups between 20 and 49 years. By 2030, colon cancer will increase by 90 percent among individuals aged 20 to 34 years and by 28 percent among those aged 35 to 49 years, the researchers noted.
For the study, researchers analyzed data from the Nurses' Health Study II on 85,256 women ages 25 to 42, most of whom were white, and were free of cancer and inflammatory bowel disease when they enrolled in the study. The women were followed up with from 1989 through 2011.
Among the women, 114 cases of early-onset colorectal cancer were documented with a median age of 45.
Those with a body mass index of 30 and above had nearly double the risk of early-onset colorectal cancer compared with women with a body mass index of 18.5 to 22.9. Excluded were women with a BMI less than 18.5.
The researchers found the association between current BMI and risk of early onset CRC was similar when the analysis was restricted to women with no family history of cancer.
In addition, women with higher current weight were more likely to have diabetes. They engaged in less physical activity, consumed more red meat and had a history of smoking. Also, BMI at early adulthood and change in weight since early adulthood were associated with the risk of early-onset CRC.
The researchers report slightly stronger associations between obesity and rectal cancer compared with cancers of the colon.
"Because of the parallel increase in obesity and early onset CRC, a thorough examination of the role of current and early-life obesity is among the first steps in our understanding of the increasing burden of early-onset CRC," the authors wrote.