Colorectal cancer screening disparities related to obesity and gender.

Background: Obesity is associated with a higher incidence of colorectal cancer and increased colorectal cancer mortality. Obese women are less likely to undergo breast and cervical cancer screening than non obese women. It is not known whether obesity is associated with a lower likelihood of colorectal cancer screening. 

Objective: To evaluate whether there is an association between body mass index (BMI) and rates of colorectal cancer screening. To examine whether BMI-related disparities in colorectal cancer screening differ between men and women. 

Design and Setting: The Behavioral Risk Factor Surveillance System, a cross-sectional random-digit telephone survey of non-institutionalized adults conducted by the Centers for Disease Control and Prevention and state health departments in the 50 states and Washington, DC in 1999. 

Patients: Survey respondents (N = 52,886) between 51 and 80 years of age representing 64,563,332 U.S. adults eligible for colorectal cancer screening. 

Interventions and Measurements: Adjusted rates of self-reported colorectal cancer screening with fecal occult blood testing within the past year or endoscopic screening (sigmoid-oscopy or colonoscopy) within the past 5 years. 

Results: The colorectal cancer screening rate was 43.8% overall. The rate of screening by FOBT within the last year or endoscopic screening within the past 5 years was 39.5% for the morbidly obese group, 45.0% for the obese group, 44.3% for the overweight group, and 43.5% for the normal weight group. The difference in screening rates was entirely attributable to differences in BMI among women. After statistical adjustment for potential confounders, morbidly obese women were less likely than normal weight women to be screened (adjusted rate difference, −5.6%; 95% confidence interval, −8.5 to −2.6). Screening rates among normal weight, overweight, and obese women, and among men in different weight groups did not differ significantly. 

Conclusions: Colorectal cancer screening rates among age-eligible persons in the U.S. are disturbingly low. Morbidly obese women, who are at higher risk than others to develop and to die from colorectal cancer, are less likely to be screened. Efforts to increase colorectal cancer screening are needed for all age-eligible groups, but should also include targeted screening of morbidly obese women since they could reap substantial clinical benefits from screening.