Monday, July 29, 2013

Odds N’ Ends: Are Tall Women More Likely to Get Cancer?

It’s rare for my work life as a health news editor and my personal time as your humble femme to intersect. But last week a story came across my desk I knew I had to cover (and share with you).

Tall Women at Higher Risk for Many Common Types of Cancer

Researchers have reached a startling conclusion after studying 145,000 post-menopausal women.

tallwomanCan height really predict a woman's likelihood of developing cancer? Researchers at Albert Einstein College of Medicine at Yeshiva University in New York City have drawn a connection between the two. 

Senior study author Dr. Thomas Rohan, chair and professor of epidemiology and population health at Albert Einstein, told Healthline that looking at how height affects the development of the disease was part of a larger exploration of obesity's role.

Four Inches Means Almost 30 Percent Greater Risk

The researchers identified nearly 21,000 cancer cases during a 12-year period among a group of about 145,000 post-menopausal women. They used formulas to control for factors other than height that could influence a person’s cancer risk: age, weight, education level, smoking and drinking habits, past cancer screenings, and whether or not they used hormone replacement therapy.

The scientists found that for every additional 4 inches of height, the women had a 13 to 17 percent greater risk of skin, breast, ovarian, endometrial, and colon cancers. Further, they had a 23 to 29 percent greater risk of kidney, rectal, thyroid, and blood cancers.

"We were surprised at the number of cancer sites that were positively associated with height. In this data set, more cancers are associated with height than were associated with body mass index," said lead study author Geoffrey Kabat, Ph.D., a senior epidemiologist at Albert Einstein, in a press release.

But body mass index, or BMI, which is one way to measure how much body fat a person is carrying, is actually a much better indication of their cancer risk, according to Dr. David Fishman, a professor in the department of Obstetrics, Gynecology, and Reproductive Medicine and director of the National Ovarian Cancer Early Detection Program at the Mount Sinai Medical Center in New York City.

“BMI is a tremendous risk factor for the development of disease, and that I think is something more tangible,” Fishman told Healthline. “This is an interesting observational study, but BMI is a much more significant factor for the development of cancer, especially endometrial cancer.” (Endometrial cancers are the most common gynecologic cancers in the United States.)

What’s the Connection?

The link between height and cancer risk shows correlation, not causation. So being tall won’t give you cancer, but some underlying factor may be responsible for both rapid childhood growth and the overactive growth of cancer cells in adulthood.

"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,” Kabat said.

Again, Fishman is skeptical. “I think that that is reaching for the stars,” he said. “It’s a well-done study, it makes one think, but there are literally thousands of scientists working on a molecular level on [what causes] malignant transformation, so to speak, so I don’t think it’s something having to do with height or a factor that makes you taller. I think there are other, better explanations.”

What This Means for Tall Women

Does this mean doctors should take a woman’s height into account when they decide how often to screen her for cancer?

Not so fast, Fishman says. “These epidemiological studies are making cultural observations,” he said. “It could also be said that blue-eyed women have a greater skin cancer risk, but it’s not because of their eye color.”

Rohan says there is no evidence to support screening tall women for cancer more often than their shorter peers. But Kabat still believes his findings are valuable and may point to a relationship between things that promote or prevent growth in childhood, such as diet, and the risk of disease later in life.

"Although it is not a modifiable risk factor [one that can be changed or treated], the association of height with a number of cancer sites suggests that exposures in early life, including nutrition, play a role in influencing a person's risk of cancer," said Kabat. "There is currently a great deal of interest in early-life events that influence health in adulthood. Our study fits within this area."

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What do you think? Is Dr. Fishman right, that the study finding was simply a coincidence? Or is Dr. Kabat on the right track when he says tall women are more likely to get cancer because of something in their genes or childhoods?