Body mass index and colon cancer screening: A systematic review and meta-analysis

Background: Obesity is associated with increased colon cancer mortality and lower rates of mammography and Pap testing. Methods: We conducted a systematic review to determine whether obesity is associated with lower rates of colon cancer screening. We searched the PubMed, CINAHL, and Cochrane Library databases. Two investigators reviewed citations, abstracts, and articles independently. Two investigators abstracted study information sequentially and evaluated quality independently using standardized forms. We included all studies in our qualitative syntheses.Weused random effects meta-analyses to combine those studies providing screening results by the following body mass index (BMI) categories: Normal, 18.5-24.9 kg/m ² (reference); overweight, 25-29.9 kg/m ²; class I obesity, 30-34.9 kg/m ²; class II obesity, 35-39.9 kg/m ²; and class III obesity,≥40 kg/m ². Results: Of 5,543 citations, we included 23 articles. Almost all studies were cross-sectional and ascertained BMI and screening through self-report. BMI was not associated with colon cancer screening overall. The subgroup of obese white women reported lower rates of colon cancer screening compared with those with a normal BMI with combined ORs (95% CI) of 0.87 (0.82-0.93), 0.80 (0.65-0.99), and 0.73 (0.58-0.94) for class I, II, and III obesity, respectively. Results were similar among white men with class II obesity. Conclusions: Overall, BMI was not associated with colon cancer screening. Obese white men and women may be less likely to undergo colon cancer screening compared with those with a normal BMI. Impact: Further investigation of this disparity may reduce the risk of obesity-related colon cancer death.