March 2 (Bloomberg) -- The World Health Organization's estimate of 39 percent growth in diabetes cases between 2000 and 2030 may be an underestimate, according to a study of cases in Canada published in the Lancet.

In just 10 years, the disease's prevalence in Ontario rose by 69 percent to nearly nine out of 100 people, according to analysis of local medical databases done by Lorraine Lipscombe of the Institute for Clinical Evaluative Sciences in Toronto and colleagues. The researchers urged more attention to obesity.

At least 171 million people have diabetes worldwide, and the number will climb to 366 million by 2030, WHO estimates. The chronic disease can lead to blindness, heart disease, kidney damage and death. Governments, which are already struggling to pay health costs for citizens, may have to spend more or cut benefits for other conditions.

``Rising rates of obesity could be a cause of this striking growth, and, accordingly, effective public-health interventions to manage and prevent obesity are sorely needed,'' Lipscombe, the lead author, said in the study. WHO likely under-estimates the disease's advance because its forecast presumes obesity rates will remain constant, she said.

The International Diabetes Federation in December said it expects more than 380 million people to have diabetes by 2025, which is ``a very conservative estimate,'' said Martin Silink, president of the organization.

Exceeding Estimates

``What we have seen since 1995, when the first estimates of prevalence were made, is that each time the prediction was made, it was exceeded,'' Silink said in a telephone interview from Sydney. The Canadian study results come as ``no surprise whatsoever,'' he said.

Diabetes comes from a person's inability to make enough, or any, insulin, a hormone that prevents sugar from accumulating in the blood. Health-care costs to treat and prevent diabetes and its complications will reach $232 billion this year and rise to more than $302.5 billion in 2025, IDF estimates.

People of African and Caribbean, Latin American and Asian descent are more susceptible to the disease, and should be targeted by testing, the Lancet said.

``Regular screening programs must be available for those most at risk, to ensure early diagnosis and effective control,'' the Lancet said in an editorial.

General screening of populations wouldn't be cost-effective, Silink said. Screening should be targeted to adults who meet four criteria: over 40, overweight, family history of diabetes and sedentary lifestyle. Children who appear at risk should be tested when they visit the doctor for unrelated reasons, he said.

While WHO estimates the percentage of diabetics worldwide will reach 6.4 percent, up from 4.6 percent in 2000, the percentage of Ontario residents who had the disease rose from 5.2 percent in 1995 to 8.8 percent in 2005, the study found. Older people were more likely to have the disease, yet its spread was more rapid among people, particularly women, from ages 20 to 49.

``This pattern might be due to a greater rise in obesity in younger than older adults,'' the researchers wrote. A greater number of people genetically susceptible to diabetes may also explain the high rate, it said. The percentage of immigrants from south Asia, who are more prone to the disease, rose 51 percent from 1995 to 2001.

WHO estimated 1.6 billion people worldwide were overweight in 2005 and at least 400 million were obese, with the numbers expected to climb to 2.3 billion and 700 million, respectively, by 2015. It attributed the rise to a shift to foods rich in fat and sugar and to a decline in physical activity.

To contact the reporter on this story: Frances Schwartzkopff in Copenhagen at fschwartzkop@bloomberg.net

Last Updated: March 2, 2007 09:59 EST