The prevalence of Type 2 diabetes worldwide has more than doubled since 1980, climbing from an estimated 153 million three decades ago to about 347 million in 2008, researchers reported Saturday. About 3 million deaths every year are directly attributable to the disease, which is caused by the body's inability to effectively use insulin secreted by the pancreas. About one in every 10 men around the world and one in every 11 women suffers from the disorder, the researchers wrote in the journal Lancet. The researchers concluded that about 70% of the increase was due to aging of the population and the remaining 30% was due to the growing incidence ofobesity, which is a major risk factor for diabetes.
A team led by epidemiologists Majid Ezzati of the School of Public Health at Imperial College London and Dr. Goodarz Danaei of the Harvard School of Public Health in Boston collected fasting blood sugars from 2.7 million people worldwide for their analysis. Fasting blood sugars are measured after a person has not eaten for 12 to 14 hours and are a good measure of that person's ability to metabolize sugars. A level below 5.6 millimoles per liter is considered normal, a level above 7 millimoles is diagnostic of diabetes, and a level between 5.6 and 7 millimoles is considered pre-diabetic. Over the 30 years of the study, the average level for men rose from 5.3 millimoles per liter 5.5, while the lever for women rose from 5.2 millimoles per liter to 5.4.
Extrapolating from their population, the researchers concluded that between 314 million and 382 million people had diabetes in 2008, with the most likely number being 347 million. A previous study using less accurate methods had estimated that the world had 285 million diabetics in 2010.
"Diabetes is one of the biggest causes of morbidity and mortality worldwide," Ezzati said in a statement. "Our study has shown that diabetes is becoming more common almost everywhere in the world. This is in contrast to blood pressure and cholesterol, which have both fallen in many regions. Diabetes is much harder to prevent and treat than these other conditions."
The team found wide variations around the world. The greatest growth was in the Pacific Island nations. In the Marshall Islands, for example, one in three women and one in four men have diabetes. Glucose levels and diabetes were also particularly high in south Asia, Latin America, the Caribbean, Central Asia, North Africa and the Middle East. Among high-income countries, the rise in diabetes was relatively small in Western Europe and highest in North America. Diabetes rates were highest in the United States, Greenland, Malta, New Zealand and Spain, and lowest in the Netherlands, Austria and France.
Of the 347 million people with diabetes, 138 million live in China and India and another 36 million in the U.S. and Russia. The region with the lowest glucose levels was sub-Saharan Africa.
The study was funded by the Bill and Melinda Gates Foundation and the World Health Organization.