How Height Is Connected to Cancer

Jealous of your long-legged peers? Turns out they may not have won the gene pool after all.

New research published in the journal Cancer Epidemiology, Biomarkers & Prevention found a surprising correlation between height and cancer risk among postmenopausal women; the taller the woman, the greater her risk for the disease.

The researchers studied more than 20,900 women ages 50 to 79 who participated in the Women’s Health Initiative (WHI)  study, an on-going analysis of post menopausal women and the factors that contribute to their health. They separated the women into five groups based on their height, starting with women shorter than 5 feet 1 inch, and matched them to data on their cancer rates.

They discovered that for every 10 centimeters of height, a woman’s risk of developing a range of different cancers increased by 13%. When they looked at all the cancers together, they found that taller women had a 13% to 17% greater risk of developing melanoma, breast cancer, ovarian cancer, endometrial cancer and colon cancer. They also had a 23% to 29% greater risk of developing kidney, rectum, thyroid and blood cancers.  All of the cancers showed a positive association with height; none of the taller women showed a lower risk of cancer compared to their shorter counterparts.

While the connection seems odd, previous studies have exposed the same association;  it’s possible, for example, that on the most basic level, the greater number of cells and tissues that taller people possess simply increases the odds that some of those cells will develop abnormally and become malignant. Alternatively, some of the same processes that fuel the growth that contributes to height may also feed tumors.

“Ultimately, cancer is a result of processes having to do with growth, so it makes sense that hormones or other growth factors that influence height may also influence cancer risk, said Geoffrey Kabat, a senior epidemiologist in the Department of Epidemiology and Population Health at Albert Einstein College of Medicine of Yeshiva University in a statement.

Some of those common factors may be genetic, while others could be linked to environmental exposures or nutrition early in life.  As the authors write:

Adult height is determined both by genetics and by early life exposures, and environmental circumstances influence the attainment of one’s genetic potential. The influence of environmental exposures on height is evidenced by the secular increase in the height of populations in many countries beginning in the 19th century, probably reflecting improvements in hygiene and nutrition. Height should thus be thought of as a marker for one or more exposures that influence cancer risk rather than a risk factor itself.

Women raised in higher socioeconomic households, for example, tended to be taller than those raised in lower income settings, reflecting the fact that different nutritional exposures may have played a role in both their height and cancer risk. Height may simply be a marker for factors such as nutrition, and identifying them may yield new understanding of about how to prevent and treat tumors more effectively, “[The association between height and cancer] raises some interesting biological questions, and investigators can come up with [new] explanations,” says the study’s senior author, Dr. Thomas Rohan, the chair and professor of epidemiology and population health at Albert Einstein College of Medicine.

In the meantime, Rohan and his colleagues say the study doesn’t imply that cancer is inevitable for every tall woman. The study found an association, not a cause-and-effect relationship. And it’s unlikely that diseases as complex as cancer can be traced to just one developmental process such as growth.

Source: http://healthland.time.com