The prevalence of diabetes in the kingdom of Tonga.
OBJECTIVE
To determine the prevalence of diabetes, impaired glucose metabolism, and related risk factors in Tonga.


METHODS
A randomly selected representative national sample of 1,024 people aged >15 years was surveyed. Each participant had fasting blood glucose and HbA(1c) measured. Subjects with a fasting blood glucose >5.0 mmol/l (90 mg/dl) and <11.1 mmol/l (200 mg/dl) or a fasting blood glucose < or =5.0 mmol/l and an HbA(1c) >6.0% and every fifth subject with a fasting blood glucose < or =5.0 mmol/l and a normal HbA(1c) had a 75-g oral glucose tolerance test (OGTT). A total of 472 individuals had an OGTT based on these criteria. Subjects with a fasting blood glucose > or =11.1 mmol/l and an elevated HbA(1c) were diagnosed as having diabetes.


RESULTS
The mean age was 41.3 years, and the mean BMI was 32.3 kg/m(2). The age-standardized prevalence of diabetes was 15.1% (CI 12.5-17.6), 12.2% (8.7-15.8) in men and 17.6% (14.0-21.1) in women (NS), of which only 2.1% was previously diagnosed. A total of 75% of people with newly diagnosed diabetes had a fasting plasma glucose > or =7.0 mmol/l (126 mg/dl). The prevalence of impaired glucose tolerance was 9.4% (7.3-11.5) and of impaired fasting glycemia 1.6% (0.7-2.6). Undiagnosed diabetes was significantly associated with increasing age, obesity, hypertension, and a family history of diabetes.


CONCLUSIONS
The current prevalence of diabetes in Tonga is 15.1%, of which 80% is undiagnosed. A similar survey in 1973 reported a 7.5% diabetes prevalence, indicating a doubling of diabetes over the past 25 years. In addition, lesser degrees of glucose intolerance are common, and much of the community is overweight
Colagiuri
Stephen
S
Australian Centre for Diabetes Strategies, Randwick, Australia. Diabetes Centre, Vaiola Hospital, Tonga.
Colagiuri
Ruth
R
Na'ati
Siva
S
Muimuiheata
Soana
S
Hussain
Zafirul
Z
Palu
Taniela
T
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D017678:Sex Distribution; D014058:Tonga / Q000453:epidemiology