A new study published in the journal Lancet reveals that taller women are at a greater risk of developing one of 10 different cancers.
Researchers observed and studied nearly 1.3 million middle-aged women in the UK for several years. They found that with every 4 inches or 10 centimeters increase in height, the risk of cancer increased by about 16%.
The question “why” continues to perplex us!
The lead author of the study and clinical epidemiologist at Oxford University, Jane Green, said that compared to the shortest group comprising women who were 5 feet and shorter, the tallest group comprising women 5 feet 9 or taller were 37% more prone to develop cancer. This observation was independent of factors such as age, socioeconomic status, body-mass index, and amount of physical activity.
Around 97,376 occurrences of cancers were reported among the women. Height related occurrences were maximum for the following types including colon, malignant melanoma, breast, endometrial, kidney, central nervous system, non-Hodgkin lymphoma, and leukemia.
Although other studies have found an association between cancer and height, the authors of this study did not examine what it was about height that contributed to the increased risk. While the study authors are uncertain about the factors that increase cancer risk, they are of the opinion that there are several other theories that necessitate further investigation.
Firstly, the authors suggest that “taller people have more cells, and thus a greater opportunity for mutations leading to malignant transformation.”
Insulin-like growth factors causing varied hormone levels both in childhood and in adult life could be another possibility.
In an email, Green explained that “Growth hormones increase cell growth and rate of division, and inhibit cell death. Both of these might be relevant to cancer either directly or perhaps just by increasing the number of cell divisions during which mutations can occur in the cell DNA.”
Earlier this year, researchers in Ecuador published a study demonstrating that Ecuadorians were at a lower risk of developing cancer and diabetes due to a condition that arrests the growth of extremely short Ecuadorians. A specific mutation in the growth hormone receptor gene was observed in all the patients of the study.
Experts at the American Cancer Society are of the opinion that tall people should not be anxious because of these findings.
Strategic director of pharmacoepidemiology, Eric Jacobs, explains that “The underlying biological reason for the slightly higher risk among taller people is not known. Nobody will be trying to make themselves shorter to lower their cancer risk, and the current results do not mean tall people need additional cancer screening.”
Smoking was found to be a much stronger risk factor, according to the study. Smoking-related cancers are not as strongly related to height in current smokers, and this according to Jacob, underlines the overwhelming significance of smoking in cancer risk.
He says, “The bottom line is that both short and tall people can lower their risk of developing and dying from cancer by not smoking, maintaining a healthy weight, and getting the recommended cancer screening tests.”
The authors note that since certain populations are continuing to increase in height, this topic necessitates further research. The study authors say that throughout the 20th century, the average height of Europeans has increased by about 1 cm (or .39 inch) per decade.
The Centers for Disease Control reported that between 1960 and 2002 in the US, the average height of a woman increased to 5 feet 4 inches from just over 5 feet 3 while that of an adult man increased to 5 feet 9 and ½ inches from just over 5 feet 8 inches.
The authors report that “The increase in adult height during the past century could thus have resulted in an increase in cancer incidence some 10–15% above that expected.”