The prevalence of diabetes in the USA has increased 5% annually since 1990 and the rise will continue unless prevention of the disease is prioritised further, according to a new report.

A study from the Centers for Disease Control and Prevention, presented at the American Diabetes Association's annual meeting in Chicago, noted that there are nearly 21 million sufferers in the USA and Linda Geiss, chief of diabetes surveillance at the CDC noted that the rise “is likely tied to the growth in obesity in this country, and if we are going to stem the growing burden of diabetes, we must improve our prevention efforts."

The study used data from the 1963-2005 National Health Interview Survey and researchers examined weight trends among adults age 20 and over and found that obesity in the US population began to increase at a more rapid rate in 1986, four years prior to the time when diabetes began to increase significantly. Diabetes costs $132 billion a year in the USA including direct medical expenses as well as indirect costs such as disability, lost work and premature death, the CDC report noted.

Also at the ADA meeting, Jinan Saaddine, a medical epidemiologist at the CDC, stated that the number of people in the USA suffering from diabetic retinopathy, which is currently 5.5 million, will reach 16 million by 2050, while Catherine Cowie, an epidemiologist with the US National Institute of Diabetes and Digestive and Kidney Diseases, focused on hearing problems caused by the disease.

Collected data on 5,140 people who had had their hearing tested during 1999-2004, Dr Cowie's team found that among the 399 people with diabetes, 31.6% had low-frequency hearing impairment, compared with 14.5% of the 4,741 non-diabetics. For higher frequencies, 56.8% of diabetics had impaired hearing, as opposed to 35.8% of non-diabetics.

Another presentation, by Xuanping Zhang of the CDC's Division of Diabetes Translation, revealed that an estimated 2.8% of people in the USA have diabetes but do not know it, and his study noted that lack of access to health care due to lack of insurance was the primary reason for this.

However another presentation suggested that while more Americans are suffering from diabetes, the level of control of the disease has risen. A study conducted by Quest Diagnostics, using data gleaned from four million people, showed that more than half of diabetics reached recommended targets for controlling blood sugar last year, compared to around a third in 2001.