Sonja Berndt

PhD, PharmD

National Cancer Institute

Senior Investigator

PLCO (Learn more about this study)

PLCO-716

Jan 14, 2021

The impact of body mass index (BMI) on cancer screening

Over the past 30 years, the prevalence of obesity has risen in the U.S. and in other countries worldwide. In 2018, the age-adjusted prevalence of obesity among adults in the U.S. was 42.4%, making it a substantial public health concern. Obesity is an established risk factor for colorectal cancer and a suspected risk factor for fatal prostate cancer. Obesity has been associated with lower PSA levels, possibly due to hemodilution. It is hypothesized that this may be one of the reasons that obese men are often diagnosed at a later stage, and it has been suggested that PSA thresholds for biopsy should lowered for obese men. Digital rectal exam may also be more difficult in obese men, leading to inadequate exams. Obesity has been associated with inadequate bowel preparation for colonoscopy, whereas lower BMI has been associated with incomplete colonoscopy. Within the PLCO Cancer Screening Trial, obesity was associated with reduced risk on inadequate sigmoidoscopy. Previous studies have suggested that body mass index (BMI) may be associated with reduced adherence to screening recommendations for breast, cervical, and colorectal cancer. Given the high rates of obesity in the U.S., we plan to further explore the impact of BMI on cancer screening and subsequent cancer risk and mortality in the PLCO Cancer Screening Trial.