WEDNESDAY, July 20, 2011 (HealthDay News) -- Tall folks may be more likely than shorter people to develop cancer, new British research says.
Among women, the risk of breast, ovarian, uterine and bowel cancer, leukemia or melanoma appears to go up about 16 percent for every 4-inch bump in stature, the researchers said.
"Taller women in our study had increased risk of a wide range of cancers," said study co-author Jane Green, from the cancer epidemiology unit at the University of Oxford in England. "And all the evidence from past studies is that this link is seen equally in men and women."
The findings also suggest that gains in height over the 20th century -- Europeans' average height grew nearly half an inch per decade -- might help explain some of the cancer differences seen in recent generations, the researchers said.
While the study found an association between height and cancer risk, it did not prove a cause-and-effect.
One expert from the American Cancer Society said the finding should not spur panic among the more statuesque.
"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," Eric Jacobs, strategic director for pharmacoepidemiology at the cancer society, said in a statement.
And, he added, the advice to Americans of any height remains the same: "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."
For their report, published online July 21 in The Lancet Oncology, the researchers analyzed data from the Million Women Study, conducted in the United Kingdom between 1996 and 2001.
The nearly 1.3 million middle-aged women enrolled in the study had undergone an initial routine breast-screening exam and completed a basic questionnaire that collected their weight and height.
None had been diagnosed with any cancer (other than some non-melanoma skin cancers), and they were tracked for more than nine years on average.
The study authors divided the women into six height categories, starting with those women less than 5 feet 1 inches tall, then adding four more groups of increasing height, and ending with the tallest group, which included women 5 feet 9 and taller.
Generally speaking, taller women tended to drink more alcohol and had fewer children than shorter women, the researchers found. Taller women were also less obese, less likely to smoke, wealthier, and more active.
Overall, regardless of most of these factors, taller women were significantly more likely to develop most cancers, with risk ratcheting upward with every increment in height.
One exception was that among women who smoked, smoking played a more pivotal role than height in influencing cancer risk.
The research team also reviewed the findings of 10 prior studies and found a similar association between height and cancer, a connection they said held across many different populations, including those in Europe, North America, Asia, and Australasia.
Of course, "people cannot change their height," Green acknowledged, "and being tall also has health advantages, such as lower risk of heart disease."
The American Cancer Society's Jacobs called the study "large and well designed" and he offered up some theories on what might be behind the link between height and cancer risk.
"One possibility is that taller people may have higher levels of growth-related hormones, both in childhood and in adulthood, and these growth-related hormones may modestly increase cancer risk," he said.
Many factors influence height, including childhood diet and health, genes and hormone levels, the study authors noted.
"The study is important not for individual or public health, but because it may help us to understand better how cancer develops," Green said.
For more on cancer risk factors, visit the U.S. National Cancer Institute.
SOURCES: Jane Green, B.M., B.Ch., D.Phil., cancer epidemiology unit, University of Oxford, Oxford, England; Eric Jacobs, Ph.D., strategic director for pharmacoepidemiology, American Cancer Society; July 21, 2011, The Lancet Oncology, online
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