Diabetes diagnoses are on the decline among American adults

Less adults are being diagnosed with diabetes than were a decade ago, a new study reports. But scientists aren't sure why.

The study, published on Tuesday, found that the rate of new diabetes cases among adults in the U.S. rose from 1990 to 2009, and since then has decreased. "But health officials are not celebrating," Stat News explained, because researchers can't pinpoint a reason behind the decline. The data is especially confusing because diabetes and obesity are two diseases that typically go hand in hand — yet obesity rates are rising in the U.S., while diabetes is on the decline.

One possibility is the prevalence of "pre-diabetes," the condition where blood sugar levels are high, but not high enough to count as diabetes. Doctors are increasingly looking out for the early warning signs, and it's possible that they encourage patients to improve their health before they are diagnosed.

Another theory suggests that a new, easier diabetes test may not be detecting as many new cases as older tests. The older tests are getting less popular because they take a long time, require fasting, or require multiple blood draws. But the new test may miss early cases of diabetes that the old tests might have caught, experts say.

With a downward trend in new diagnoses, the number of diabetic adults in the U.S. is holding steady at about 80 cases for every 1,000 people. That amounts to 21 million American adults who have diabetes. Read more at Stat News.