A team of researchers at Mayo Clinic has found that genetics often determine the amount and location of abdominal fat in postmenopausal women. Abdominal fat is a proven risk factor for diabetes, heart disease, breast cancer and many other chronic conditions.
"We have gathered additional evidence showing a major gene influence on the distribution of abdominal fat in postmenopausal women," says Mayo Clinic researcher, Janet Olson, Ph.D., whose findings were recently published in the May 2001 edition of Genetic Epidemiology. "With this information, we can conduct further studies to try to locate the gene that influences how and where excess weight is carried in our bodies."
Dr. Olson and colleagues drew their conclusions from a method called segregation analysis, which looks at how a trait moves across generations in a family. Women from the Family Studies of Cancer were investigated for this analysis. This study started about 50 years ago, when a doctor at the University of Minnesota collected pedigrees from more than 500 women. Today, information from this group of women and their families continue to be collected and studied by Mayo Clinic researchers.
There are different ways to measure the amount of abdominal fat in a person’s body. Dr. Olson and colleagues used the measurement called the "waist-to-hip ratio," which is the measurement of a woman’s waist circumference divided by her hip circumference (WHR). This measurement method is commonly used in large-scale studies. "In general, lower levels of abdominal fat are better, and a low waist-to-hip ratio is healthier," Dr. Olson says.
Researchers looked at the group of women in three ways: premenopausal women alone, postmenopausal women alone, and all women combined. "Abdominal fat distribution did not appear to be influenced by a major gene in premenopausal women, as opposed to what was found in postmenopausal women," Olson explains. She adds that women tend to carry their fat differently after menopause, meaning that "there may be a difference in how genes are expressed after menopause."
With this evidence, researchers have decided to continue their study. "Since we have evidence that a gene influences abdominal fat distribution, we’re going to do a ‘linkage analysis’ to locate the major gene influencing fat distribution," Olson said. This involves obtaining blood samples from family members to directly examine their genes.
This group of women and their families will continue to be studied, as the researchers collect additional information and expand their study to include future generations and more distant relatives.
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