Fat and Obesity Gene may Increase Risk of Hip Fractures

A new study by Australian researchers takes an in-depth look at a strong link at how the fat and obesity gene can affect hip fractures, particularly in women.

While previous research shows that the gene can affect diabetes and body fact, this is the first study to look at the high-risk for this health problem by as much as 82 percent.

Study authors Dr. Bich Tran and Professor Tuan Nguyen from Sydney's Garvan Institute of Medical Research worked to examine six gene variants of the FTO gene that's taken from the DNA of 934 women in the Dubbo Osteoporosis Epidemiology Study (DOES). All participants were over the age of 60 and their bone health was followed between 1989 and 2007. During that period, 102 had hip fractures, according to the study.

Background information from the study notes that the average risk of fracture is approximately 11 percent. For instance, if a woman has a low-risk genotype or gene variant, the risk fracture is 10 percent. However, if she has a high-risk genotype, the risk is greater at 16 percent.

"We found that for a woman of the same age and same clinical risk factors, those with the high-risk genotype have an increased risk of fracture of 82% - a very high effect in genetic terms," said Professor Tuan Nguyen, via a press release.

"A genome-wide association study published in 2007 suggested that genetic variants in the FTO gene were associated with variation in BMI. This led us to hypothesise that they might also be associated with variation in hip fracture risk." 

"The present study tested our hypothesis by examining the association between common variants in the FTO gene and hip fracture."

"Our results showed a strong association with hip fracture, with some gene variants doubling the risk of fracture. Interestingly, this was independent of both the bone density and BMI of the women we studied." 

"We also found that the FTO gene expresses in bone cells, and may have something to do with bone turnover, or remodelling, although its exact mechanisms are unclear."

"It's important to emphasise that, while promising, our finding is a first step.  It will need to be replicated in other studies, and its mechanisms clearly understood before it is useful in drug development."

"At Garvan, we developed a Fracture Risk Calculator several years ago, www.fractureriskcalculator.com, using algorithms based on data from the Dubbo study. The calculator, which is fairly accurate and easy to use, is very popular with patients and doctors."

"In the future, I would anticipate that genetic risk factors including this finding would be programmed into the calculator, making it an even more finely-tuned predictive tool."

More information regarding this study can be found via the journal Clinical Endocrinology.