Correlates of screening sigmoidoscopy use among men in a large nonprofit health plan.

Background: As the majority of patients diagnosed with colorectal cancer have no known risk factors, regular screening is strongly recommended. The authors examined factors associated with screening sigmoidoscopy use among participants in the California Men's Health Study (CMHS).

Methods: The authors conducted a cross-sectional study over a 5-year period nested within a prospective cohort study. The CMHS enrolled a large multiethnic cohort (n = 84,170) of men from 2 major California health plans. Because screening sigmoidoscopy was the preferred and most commonly used test for patients at average risk of colorectal cancer in the health plans, the authors excluded from the analysis men who completed a barium enema colonoscopy or a fecal occult blood test.

Results: Eligible subjects included 39,559 men at average risk for colorectal cancer. Prevalence of screening sigmoidoscopy use decreased with older age and increased with higher education and household income over the 5-year study period. Compared with whites, Asians (adjusted OR, 1.42; 95% CI, 1.30-1.56) and African Americans (adjusted OR, 1.18; 95% CI, 1.08-1.29) were more likely to undergo screening sigmoidoscopy. Screening increased with the number of outpatient visits and with having a primary care provider in internal medicine. Men who did not undergo prostate-specific antigen testing were also less likely to undergo sigmoidoscopy screening. Only 24.5% of current smokers had a screening sigmoidoscopy examination and were 25% less likely to undergo this procedure compared with nonsmokers (adjusted OR, 0.75; 95% CI, 0.69-0.82).

Conclusions: In this insured population for whom financial barriers are minimized, screening sigmoidoscopy use was as low as reported in the general population. However, minority patients were not less likely to be screened.