Cancer risk higher in tall women

[Jackie07]

I remember someone asked the question about our height one time and discussed a little bit about the relation of our height and cancer risk. Well, the verdict is in:

Cancer Risk Higher in Tall Women
By Nancy Walsh, Staff Writer, MedPage Today
Published: July 20, 2011
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
Tall women are at greater overall risk for cancer than their short counterparts, although the degree of risk varies depending on the type of cancer, a large U.K. prospective study confirmed.

Overall, for every four-inch increase in height over 5 feet, women had a 16% greater risk of developing cancer (95% CI 1.14 to 1.17, P<0.0001), according to Jane Green, DPhil, of the University of Oxford, and colleagues.

So, women who were 5 feet 9 inches tall had a relative risk for cancer of 1.37 (95% CI 1.33 to 1.42) compared with those who topped out at just 5 feet (P<0.0001), the researchers reported online in Lancet Oncology.

The highest relative risks per four-inch height increase were for malignant melanoma, RR 1.32 (95% CI 1.24 to 1.40), kidney cancer, RR 1.29 (95% CI 1.19 to 1.41), and leukemia, RR 1.26 (95% CI 1.15 to 1.38).
Previous studies have found an increase in cancer risk in taller people, but data on specific cancer sites and how other factors such as smoking and socioeconomic status might contribute have been lacking.
To explore these associations, Green and her colleagues analyzed data from the Million Women Study, which enrolled 1.3 million women between 1996 and 2001.
Participants' mean age was 56, and mean height was 5 feet 3 inches.
During 11.7 million person-years of follow-up there were 97,376 new cases of cancer.
Statistically significant increases in risk for each four-inch increase in height also were found for these specific cancers:

• Colon, RR 1.25 (95% CI 1.19 to 1.30)
• Rectum, RR 1.14 (95% CI 1.07 to 1.22)
• Breast, RR 1.17 (95% CI 1.15 to 1.19)
• Endometrium, RR 1.19 (95% CI 1.13 to 1.24)
• Ovarian, RR 1.17 (95% CI 1.11 to 1.23)
• Central nervous system cancers, RR 1.20 (95% CI 1.12 to 1.29)
• Non-Hodgkin lymphoma, RR 1.21 (95% CI 1.14 to 1.29)

"It's remarkable that the effects of height were so similar for cancer with very different etiologies and risk factors," observed Bruce J. Trock, PhD, of Johns Hopkins.
"There are also data from other studies that suggest even in utero exposures such as the hormonal and nutritional milieu may influence risk later in life," Trock, who was not involved in the study, said in an email to MedPage Today and ABC News.
When the researchers considered personal factors that might influence height-related cancer risk -- such as socioeconomic status, age at menarche and at birth of the first child, smoking, physical activity, and use of oral contraceptives -- they found a correlation only with smoking.
But it was a negative correlation -- current smokers, had a lower risk of cancer for each four-inch increase in height than women who had never smoked (P<0.0001).
Green's group then conducted a meta-analysis including their findings and data from 10 additional prospective studies that evaluated height and cancer risk in both women and men in many populations around the world.
They found an overall relative risk of 1.14 (95% CI 1.13 to 1.15) for each four-inch increase in height, with the risk being slightly lower for men (1.10 versus 1.15, P<0.0001).
The higher height-related risk among women may be explained by the fact that fewer women than men were active smokers, according to the researchers.
But in general, the meta-analysis found "very consistent" results over time and across populations and for heights ranging from 60 to 70 inches.
"The similarity of the height-associated RR for different cancers and in different populations suggests that a basic common mechanism, possibly acting in early life, might be involved," the researchers observed.
Among possible contributing factors are genetics, nutrition, and hormones such as insulin-like growth factors, they said.
"Another possibility is that height predicts cancer risk because taller people have more cells (including stem cells) and thus a greater opportunity for mutations leading to malignant transformation," the researchers explained.
In a comment accompanying the study, Andrew G. Renehan, PhD, of the University of Manchester in England, called for more investigation into other factors that could affect later-life cancer risk.
"In the future, researchers need to explore the predictive capacities of direct measures of nutrition, psychosocial stress, and illness during childhood, rather than final adult height," he stated.
Other experts not involved in the study pointed out in emails to MedPage Today and ABC News the greater significance of other risk factors.
"Two-thirds of cancer risk is attributable to lifestyle factors such as diet and physical activity," wrote Denise Snyder, RD, of Duke University.
"The public should follow the World Cancer Research Fund and American Institute for Cancer Research recommendations for the prevention of cancer," she added.
"No one can modify their height, and the increased risk with height is small," noted Trock.
"The real challenge is to identify modifiable risk factors," stated David M. Euhus, MD, of the University of Texas Southwestern Medical Center in Dallas.
http://www.medpagetoday.com/Hematolo...&userid=317363