The carpal tunnel is found in the wrist. In carpal tunnel syndrome, a nerve in the carpal tunnel becomes pinched due to swelling of the nerve and/or nearby tendons.
The pinched nerve can cause numbness, tingling, and sometimes pain in the fingers, hand, and forearm.
It's well known that people with diabetes are more likely to get carpal tunnel syndrome. But researchers wanted to find out if the risk actually goes up before diabetes develops -- when a person has pre-diabetes.
So, researchers, including Martin Gulliford, FRCP, of King's College in London, looked at 2,655 patients with pre-diabetes who later went on to develop diabetes. They were compared with nearly 5,300 people without the disease.
Next, Gulliford's team scrolled back through nearly nine years of the patients' medical records.
The researchers found that people who had been diagnosed with carpal tunnel syndrome were 36% more likely to later be diagnosed with diabetes, regardless of other diabetes risk factors.
That finding appears in the latest issue of Diabetes Care.
The study doesn't prove carpal tunnel syndrome causes diabetes.
Only 82 patients in the study had been diagnosed with carpal tunnel syndrome. That number may be too small to draw firm conclusions, the researchers note.
But nerve problems are associated with diabetes, Gulliford's team says.
If the study's finding is correct, it may show that high blood sugar and other metabolic abnormalities can start affecting the body years before diabetes is diagnosed.