July 26, 2013
Height May Raise Cancer Risk In Women
redOrbit Staff & Wire Reports - Your Universe Online
Taller postmenopausal women are at greater risk for developing cancer, although other factors that influence height might also be involved, according to a study published Thursday in the journal Cancer Epidemiology, Biomarkers & Prevention.
The link was seen across a number of cancers, including breast, colon, endometrium, kidney, ovary, rectum, and thyroid, as well as multiple myeloma and melanoma. These associations did not change even after adjusting for factors known to influence these cancers, such as genes, nutrition, diet and other environmental influences, the researchers said.
"We were surprised at the number of cancer sites that were positively associated with height," said study leader Geoffrey Kabat, Ph.D., senior epidemiologist in the Department of Epidemiology and Population Health at Albert Einstein College of Medicine of Yeshiva University in New York.
However, the researchers don't believe that being tall gives a person cancer, but that height "should be thought of as a marker for one or more exposures that influence cancer risk, rather than a risk factor itself," the researchers said.
"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.
The study involved 20,928 postmenopausal women ages 50 and 79 identified from a large cohort of 144,701 women recruited to the Women's Health Initiative (WHI) between 1993 and 1998.
"In this data set, more cancers are associated with height than were associated with body mass index," Kabat said.
Kabat and colleagues began their study by asking WHI participants to answer questions about physical activity, and measuring their height and weight. The researchers then identified 20,928 women who had been diagnosed with one or more invasive cancers during a 12-year follow up period.
To study the effect of height, the researchers accounted for many factors that influence cancer, such as age, weight, education, smoking habits, alcohol consumption and hormone therapy.
They found that for every 3.94 inch (10 centimeter) increase in height, there was a 13 percent increase in risk of developing any cancer.
Among specific cancers, there was a 13 percent to 17 percent increase in the risk of developing melanoma and cancers of the breast, ovary, endometrium and colon, and a 23 percent to 29 percent increase in the risk of developing cancers of the kidney, rectum, thyroid, and blood.
Of the 19 cancers studied, none showed a negative association with height, the researchers said.
Because the ability to screen for certain cancers could have influenced the results, the researchers added the participants' mammography, Pap and colorectal cancer screening histories to the analyses, but found the results remained unchanged.
"Although it is not a modifiable risk factor, 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 with this area."
Some genetic variations associated with height are also linked to cancer risk, but more research is needed to examine how these variations predispose some men and women to cancer, the study's authors concluded.