The number of Americans diagnosed with diabetes is continuously rising, reaching double the cases diagnosed ten years ago, according to a study released Friday by the US Centers for Disease Control and Prevention.

The finding should come as no surprise considering the fact that obesity, a condition strictly related to diabetes, is also rising in the US, especially in the South, a region registering the lowest levels of physical activity.

The study was based on random-digit-dialed survey of more than 260,000 adults in 33 states between 1995-97 and 2005-07 for which the CDC had complete data.

Overall, the study found that an estimated 23.6 million American adults and children have diabetes, but about one-quarter of them do not know they have the disease. About 90-95 percent of cases are type 2 diabetes. The findings show that new diagnoses of type 2 diabetes rose from 4.8 per 1,000 people from 1995 to 1997 to 9.1 per 1,000 people from 2005 to 2007. However, there are states in the South which had rates higher than 9.1 per 1,000 people. For example, West Virginia, South Carolina, Alabama, Georgia, Texas and Tennessee had the highest rates, all at 11 cases per 1,000 or higher. On the other hand, Minnesota, Hawaii and Wyoming had the lowest rates, about 5/6 per 1,000 people.

The bad news is that type 2 diabetes is not easily recognized, so it’s often diagnosed when people develop one of the disease’s serious complications, such as heart attack, kidney failure, blindness or nerve damage that can lead to amputations.

What people can do to lower their risk of diabetes? Well, health care experts have always stressed the idea of maintaining a healthy lifestyle. This involves keeping a healthy weight, having a healthy diet and a regular program of exercises.

The study was published in the Oct. 31 issue of CDC’s Morbidity and Mortality Weekly Report.