There are 1,400,000 new cases of colorectal cancer each year worldwide, representing about 15% of cancer incidence. In drawing attention to the “height” criterion in the risk of this cancer, a Johns Hopkins Medicine team, in the journal Cancer Epidemiology Biomarkers & Prevention, suggests the importance of more regular screening in taller adults.
With this meta-analysis, the Baltimore team adds to evidence showing that taller adults are more likely than shorter people to develop colorectal cancer or colon polyps that can then develop into malignancies. Although this link between height and cancer risk has been studied before, this analysis, the largest to date, reinforces previously suggested links between greater body height and colorectal cancer risk.
Height is an overlooked risk factor
This meta-analysis of 47 studies included data from 280,660 cases of colorectal cancer and 14,139 cases of colorectal adenoma, as well as, in a related study, data from 1,459 patients who underwent colonoscopy. 459 patients who underwent a colonoscopy to investigate the relationship between cancer and biofilm bacteria in the colon, it appears that size may confer an order of magnitude risk of colorectal cancer, comparable to better-known modifiable factors such as smoking, drinking alcohol, and eating processed red meat. This conclusion remains valid after adjustment for most of the possible confounding factors (demographic, socioeconomic, behavioral, and other variables) known to be associated with colorectal cancer. These risk factors include so-called non-modifiable factors, such as age, personal or family history of colorectal cancer or adenomas, and personal history of chronic inflammatory bowel disease).
Lead author Dr. Gerard Mullin, associate professor of gastroenterology and hepatology at Johns Hopkins Medicine, emphasizes the need to take this hitherto neglected criterion into colorectal cancer screening. Although the study does not show a causal effect height seems to be as important a factor in the link as age or genetics.
One possible explanation for this link is that adult height correlates with body organ size. More active proliferation in the organs of taller people could increase the likelihood of mutations leading to malignant development,” adds Dr. Elinor Zhou, one of the lead authors of the analysis.
Making the public and doctors more aware of this neglected criterion is no small feat. This criterion should be added to the better-known adaptive dietary associations for colorectal cancer. Finally, it is very important that tall people should be screened earlier and perhaps more often.