A new meta-analysis provides more evidence that
“There are well-known modifiable dietary associations for colorectal cancer, such as processed red meats and smoking, but guidelines currently are fixated on family history, and height is clinically neglected when it comes to risk screening,” study investigator Gerard Mullin, MD, with Johns Hopkins University, Baltimore, said in a news release. This large study “builds on evidence that taller height is an overlooked risk factor and should be considered when evaluating and recommending patients for colorectal cancer screenings.”
The study was published online March 1 in Cancer Epidemiology, Biomarkers & Prevention.
The evidence: Height and cancer risk
Height has been actively studied as a potential nonmodifiable risk factor for a range of cancers, including CRC.
In one large prospective study of postmenopausal women, researchers found a modest but statistically significant positive association between height and risk for any cancer and for melanoma, multiple myeloma, and cancers of the thyroid, ovary, colorectum, and endometrium.
A separatefound that tall men, especially those who are long-legged, may be at increased risk for prostate cancer, including high-grade tumors, relative to men of more modest stature.
However, the study authors point out, past studies have also produced mixed results, used inconsistent measures of height, and failed to include the risk of adenomas.
In the current meta-analysis, the investigators included 47 international, observational studies involving 280,644 adults with CRC and 14,139 cases of colorectal adenoma.
Because the definition of tallness differs around the world, the researchers compared the highest versus the lowest height percentile of various study groups. The findings were adjusted for demographic, socioeconomic, behavioral, and other known risk factors for CRC.
Overall, the investigators found that the tallest individuals within the highest percentile of height had a 24% higher risk of developing CRC compared to the shortest individuals within the lowest percentile (hazard ratio [HR], 1.24; P < .001).
In addition, they found that every 10-cm increase (about 4 inches) in height was associated with a 14% increased risk of developing CRC (HR, 1.14; P < .001) and a 6% increased likelihood of adenomas (odds ratio [OR], 1.06; P = .03).
In the United States, the average height for men is 5 feet, 9 inches, and for women it is 5 feet, 4 inches, which means men who are 6 feet, 1 inch and women who are 5 feet, 8 inches or taller have a 14% increased risk of CRC and a 6% increased risk of adenomas, the researchers explained.
According to co–first author Elinor Zhou, MD, also with Johns Hopkins University, a potential explanation for this link “is that adult height correlates with body organ size. More active proliferation in organs of taller people could increase the possibility of mutations leading to malignant transformation.”
The study authors said more research is needed to identify particular subgroups of tall people at risk for CRC.
“For instance, tall athletes and individuals with inherited tallness, such as those with Marfan syndrome, could be screened earlier and the impact of height further explored,” Dr. Zhou said.
Plus, Dr. Zhou added, more studies are needed to “definitively say at what height you would need earlier colorectal cancer screening.”
The current study was supported by grants from Bloomberg Philanthropies, intramural funds, and the Johns Hopkins Cancer Center Support Grant. The authors declared no conflicts of interest.
A version of this article first appeared on.