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'Obesity Signature' Written in Pee

A heavy woman stands back-to-back with a thin woman.
(Image credit: hartphotography/Shutterstock)

A person's urine could reveal whether he or she is at risk for obesity and its related harmful conditions, a new study suggests.

Researchers analyzed information from more than 2,000 people in the United States and United Kingdom. The subjects had samples of their urine collected over two separate 24-hour period periods, three weeks apart.

The researchers found 25 chemical markers in the urine that were linked with the participants' body mass index (BMI), a ratio of height and weight that is an indicator of body fatness. The researchers call these 25 markers a "metabolic signature" of obesity.

"Our results point to patterns of metabolic markers in the urine associated with obesity," Dr. Paul Elliott, a co-author of the study and the head of the department of epidemiology and biostatistics at Imperial College London, said in a statement.

Nine of the markers that the researchers found were compounds that gut bacteria produce when they break down food, a finding that agrees with previous research linking gut bacteria with obesity. And at least one marker was a breakdown product in a biological pathway that is linked to heart disease.

Some of the markers of were related to muscle metabolism, with lower levels of these markers found in people with higher BMIs. This finding may support the idea that not only diet, but also exercise has a role in controlling obesity, the researchers said.

The study also found that higher blood-sugar levels were linked with high BMI, and some participants' levels were high enough that it could indicate undiagnosed diabetes, the researchers said.

In addition, a compound tied to fruit intake was linked with low BMI. [5 Ways Gut Bacteria Affect Your Health]

It may be possible to identify nonobese people who have this metabolic signature of obesity in their urine, Elliott said. "These people could be at risk of developing obesity and other metabolic diseases, and might benefit from personalized preventative interventions," he said.

"In this way, the future disease burden associated with the obesity epidemic may be reduced," the researchers wrote in the April 29 issue of the journal Science Translational Medicine.

Because the study was conducted at one point in time, it cannot directly determine whether the markers are a cause or effect of obesity, the researchers said. More research is also needed to identify exactly how alterations in metabolism produce the obesity "signature."

Follow Rachael Rettner @RachaelRettner. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Rachael Rettner
Rachael has been with Live Science since 2010. She has a masters degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a Bachelor of Science in molecular biology and a Master of Science in biology from the University of California, San Diego.