The number of people with diabetes in Tonga has decreased, according to new Australian research.
The finding contradicts a prediction by the World Health Organisation that the diabetes rates would double.
Researchers from the University of New South Wales and the Baker IDI Heart & Diabetes Institute say that tests carried out for the World Health Organisation in Tonga (2004) and Fiji and Samoa (2002) were flawed.
Their work has been published as an article, ‘Erroneous inflation of diabetes prevalence: Are there global implications?’ in the Journal of Diabetes.
And according to members of the same team, there are so many discrepancies between the different methods used to test for diabetes around the world that the true global figure for the disease may have been underestimated by up to 100 million people.
The WHO surveys looked at the prevalence of diabetes in those countries. The researchers compared the results with follow-up surveys done 11 years later.
They said that because an incorrect procedure had been used in the original WHO surveys, the rate of the increase of diabetes appeared to be double what it actually was.
In Tonga the prevalence surveys suggested a 12% increase, from 22.4% in 2004 to 34.4% in 2012. The new research said that the actual rate from corrected data showed it had actually decreased by 3.4% to 19.0%.
According to current WHO figures, 19.1% of males and 24.5% of females in Tonga have diabetes. The figures are matched by much higher levels of obesity, a situation which has led Tonga to be christened “the diabetes heavyweight of the Pacific.”
The WHO predicts a doubling of the number of the number of cases in Tonga by 2030, a progression it makes for other Pacific island countries as well.
The report said the inflated reports on the prevalence of diabetes 2 had affected public health policy, monitoring, and evaluation, as well as advocacy and program planning in the Pacific region.
The report’s co-author, Professor Richard Taylor, said the WHO surveys were crucial because they gave an indication of the success, or otherwise, of health intervention programs.
“These WHO surveys are widely cited and used as a reference by many organisations and individuals to make public health decisions which then influence future health program planning in the Pacific region,” Professor Taylor said.
Report co-author Professor Paul Zimmet, said it might be necessary to recalculate results in other countries where diabetes rates might now be suspect.
In an interview with the Australian Broadcasting Corporation earlier this year, Professor Zimmett said three different methods were used to test for diabetes.
Because they did not all sample the same things, overall global figures for diabetes might be wrong.
He told the ABC that the true figure may have been underestimated by 100 million.
Zimmett cited a paper published in Nature Reviews earlier this year which said that while the official prediction of diabetes sufferers was 415 million people, it could actually be more than 500 million people.
The main points
- The number of people with diabetes in Tonga has decreased, according to new Australian research.
- The finding contradicts a prediction by the World Health Organisation that the diabetes rates would double.
- The report said that in Tonga the WHO prevalence surveys suggested a 12% increase, from 22.4% in 2004 to 34.4% in 2012.
- The actual rate from corrected data decreased by 3.4% to 19.0%.
For more information
Dramatic rise in Pacific Islands diabetes cases questioned due to ‘methodological errors’ (Gary Scattergood)
WHO diabetes programme
Tonga health profile 2016 (WHO)
Tonga – the diabetes heavy weight of the Pacific
Diabetes prevalence could be severely underestimated: Researchers
