Objectives: In 2003, the International Agency for Research on Cancer as part of the World Health Organization concluded that sufficient evidence existed for a causal link between obesity and increased risk of colorectal cancer (CRC). Previous studies have found that obese people have 50% to three-fold increased risk of CRC compared to normal weight, as well as 23-90% increased risk of mortality from CRC. Thus, colorectal cancer screening (CRS) in this high risk population may be a key factor in decreasing CRC morbidity and mortality. Studies found that obese individuals were less likely to be screened for CRC or breast cancer. Whether this phenomenon is also happened in the Asian-American population remains unknown. The purposes of this study were to: 1) evaluate whether there was an association between body mass index (BMI) and rates of colorectal cancer screening (CRS) among Asian Americans; and 2) examine whether BMI-related disparities in CRS differ between Asian men and women.

Methods: This was a cross-sectional study using data collected from the Chicago Asian Community Survey (CACS). Participants were recruited from three Asian communities, Chinese, Cambodian and Vietnamese, using a three-stage random sampling of the Chinese community and Respondent Driven Sampling (RDS) of the Cambodian and Vietnamese communities. The CACS consisted of face-to-face interviews and was conducted following cultural and language-specific survey guidelines. The survey questionnaire was developed from several validated national health surveys, including the Centers for Disease Control and Prevention's Behavioral Risk Factor Surveillance System (BRFSS), National Health and Nutrition Examination Survey (NHANES), and the National Health Interview Survey (NHIS). In this study, BMI was calculated using self-reported height and weight. Overweight was defined as BMI ≥ 24kg/m2, which is the recommendation cut-off for Asian populations by the World Health Organization. The main dependent variable was self-reports of having either sigmidoscopy or colonoscopy in the past.

Results: A total of 783 participants completed the survey, and 482 met the age criterion (50 or older). The proportion of participants who reported ever having a sigmoidoscopy or a colonoscopy was 27% for the Chinese, 31% for the Vietnamese, and 36% for the Cambodian, and there were no significant differences among the three communities. About 36% of the participants had BMI ≥ 24kg/m2. Only 24% whose BMI ≥ 24kg/m2 have ever screened for CRS compared to 34% of those whose BMI < 24kg/m2 (OR = .54, 95% CI .34 - .86). Even after adjusting for the socioeconomic status (insurance coverage, a regular place for health care, employment status, family annual income, years in the U.S., and education level), the difference remained significant (OR = .52, 95% CI .32 - .84). BMI-related disparities in CRS did not exist between overweight men and women, only 23% overweight women and 27% overweight men, whose BMI ≥ 24kg/m2, have ever had CRS.

Conclusion: Although avoidance of weight gain should become one of the mainstays of CRC prevention, compliance of CRS guidelines for CRC among overweight and obese adults can reap substantial clinic benefits. Colorectal cancer screening rates among age-eligible Asian-Americans in the U.S. are disturbingly low. Efforts to increase CRS in age-eligible Asian-Americans are urgently needed, but should also include targeted screening of overweight and obese adults. Barriers to CRS in overweight Asian-Americans other than socioeconomic status may exist, and further exploration is needed to identify these barriers.

Citation Format: Edwin Chandraskar, Helen Lam, Karen Kim. Colorectal cancer screening among overweight versus non-overweight Asian Americans. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr A77. doi:10.1158/1538-7755.DISP13-A77