Hormone level linked to colorectal cancer risk
Low levels of a hormone secreted by fat cells, independent of body mass index (BMI)—a measure of Obesity—are associated with an increased risk of colorectal cancer in men, according to a report in the Journal of the National Cancer Institute.
Previous reports have linked body fat and insulin resistance with colorectal cancer risk. Since adiponectin, an insulin-related hormone secreted by fat cells, is inversely associated with both these factors, Dr. Esther K. Wei, from Harvard Medical School in Boston, and colleagues hypothesized that it too would be tied to the risk of this malignancy.
The analysis involved 18,225 men who participated in the Health Professionals Follow-up Study. Adiponectin levels were measured in blood samples given in 1994 and the subjects were followed through 2002 to identify cases of colorectal cancer. For risk determination, the patients who developed colorectal cancer were matched to two control subjects by birth year and date of blood draw.
During follow-up, 179 men developed colorectal cancer. Men with the highest adiponectin levels were 52 percent less likely to develop this cancer than their peers with the lowest levels. Moreover, factoring in BMI and other major risk factors for colorectal cancer had little effect on the strength of this association.
“There’s been more and more evidence that (fat) tissue isn’t just inert, that it’s actually secreting hormones,” Wei told Reuters Health. “So it may be involved in disease processes.”
“The fact that the link between adiponectin levels and colorectal cancer risk remained after accounting for BMI, suggests that it’s not simply a proxy measure of body fatness,” Wei said.
“Studies are needed to investigate this association in women,” Wei added. “In general, BMI is not as strongly tied to colorectal cancer in women as in men. Also, adiponectin levels differ between the sexes, so it’s possible that the association seen in men does not apply to women.”
SOURCE: Journal of the National Cancer Institute, November 16, 2005.
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