Prevalence of diabetes and IGT in Yonchon County, South Korea

Prevalence of type 2 diabetes mellitus and impaired glucose tolerance in a rural area of Japan. The Funagata diabetes study

PURPOSE

To determine the prevalence of type 2 diabetes and impaired sucrose tolerance (IGT) among people aged 40 and over in a rural area, Funagata, Japan, by using a 75-g oral glucose tolerance test (OGTT), and to compare the prevalence to that obtained from a more urban area, Hisayama, Japan.

METHODS AND RESULTS

Total eligible subjects for the Funagata study were 3526. Among them, 140 were confirmed to have diabetes judged by the 1985 WHO criteria. A 75-g OGTT was conducted, excluding the 140 known cases of diabetes. The 1985 WHO criteria were used to classify the current diabetes status of participants. The overall participation rate was 74.4%. The prevalence of diabetes (known and newly diagnosed cases combined) was 9.1% for men and 10.8% for women. The prevalence of IGT was 12. 0% for men and 16.5% for women. Age-adjusted prevalence (using 1990 Japanese census) of diabetes and IGT in men in Hisayama is two times higher than in Funagata (12.8% vs. 6.8% for diabetes, 19.5% vs. 10. 3% for IGT). Age-adjusted prevalence of IGT in women in Hisayama is significantly higher than in Funagata.

CONCLUSIONS

The prevalence of type 2 diabetes among people aged 40 and over is approximately 10% even in a rural area of Japan. Prevalence of diabetes and IGT is much higher in an urban area than in a rural area in Japan.

Comparison of glucose tolerance categories in the Korean population according to World Health Organization and American Diabetes Association diagnostic criteria

OBJECTIVES

To compare the prevalence and metabolic profiles of glucose tolerance categories according to World Health Organization(WHO) and 1997 American Diabetes Association(ADA) fasting criteria for the diagnosis of diabetes mellitus and impaired glucose metabolism in the Korean population.

METHODS

2251 subjects without previous history of diabetes, who participated in the Yonchon diabetes epidemiology survey in 1993, were classified according to both criteria. The prevalence of glucose tolerance categories and the agreement across all categories of glucose tolerance were calculated. Metabolic characteristics of different glucose tolerance categories were compared.

RESULTS

The prevalence of diabetes and impaired fasting glucose(IFG) according to ADA fasting criteria was similar to those of diabetes and impaired glucose tolerance(IGT) according to WHO criteria, respectively. However, 35.5% of the subjects who were diagnosed as diabetes by WHO criteria were reclassified as either IFG or normal fasting glucose (NFG), and 38.5% of diabetic patients according to ADA fasting criteria were IGT or normal glucose tolerance (NGT) by WHO criteria. Only 31.3% of IGT subjects remained as IFG and 62.1% were reclassified as NFG. Similarly, 69.4% of IFG subjects were NGT by WHO criteria. The agreement between the two criteria was poor (K = 0.31). Discordant diabetes groups had higher WHR, systolic and diastolic blood pressure, cholesterol and triglyceride levels than concordant non-diabetes group. Non-diabetes(WHO)/diabetes(ADA) group had higher WHR than diabetes (WHO)/non-diabetes(ADA) group. There were no differences in other metabolic characteristics between the two discordant diabetes groups. IGT/NFG and NGT/IFG group showed higher BMI, WHR, systolic and diastolic blood pressure, cholesterol and triglyceride levels than NGT/NFG group. Metabolic characteristics of IGT/NFG group were not different from those of NGT/IFG group except IGT/NFG subjects were older than NGT/IFG subjects.

CONCLUSION

The agreement between WHO and ADA fasting criteria was poor. ADA fasting criteria can detect new diabetic patients and subjects with impaired glucose metabolism who are not classified as diabetes or IGT by WHO criteria. However, a substantial number of subjects, who may have increased cardiovascular risk and/or increased risk for the development of diabetes and its complication, will be missed when using ADA fasting criteria.

High prevalence of impaired fasting glucose and type 2 diabetes mellitus in Penghu Islets, Taiwan: evidence of a rapidly emerging epidemic?

The purpose of this study was to estimate the prevalence of type 2 diabetes and impaired fasting glucose (IFG) in Penghu, Taiwan and compare these estimates with those of the US (NHANES III). Diabetes and IFG (American Diabetes Association criteria, 1997) were assessed among a stratified random sample of 2500 residents of Penghu Islands, Taiwan. The prevalence (age-adjusted to world adult population) of diabetes and IFG were 16.8% (95% CI 15.0-18.6) and 21.0% (95% CI 19.0-23.0), respectively, among Penghu Islanders in Taiwan. Age sex-specific diabetes prevalence ranged from 10.0% in men aged 40-49 years to 29.4% in women aged 60-69 years. Prevalence of IFG ranged from 14.7% in women aged 40-49 years to 30.7% in men aged 50-59 years. Age, body mass index (BMI), and family history of diabetes were each independently associated with both diabetes and IFG. In addition, female gender, apolipoprotein B and triglyceride concentrations were associated with diabetes, and hypertension and apolipoprotein B concentration with IFG. Among persons > or = 40 years in Penghu, Taiwan, the prevalence of diabetes is up to a third higher and the prevalence of IFG is up to three times higher than comparably aged Americans, despite their having a mean BMI 2.2-3.2 kg/m2 lower than Americans. The alarmingly high prevalence of IFG in Taiwan may indicate an emerging diabetes epidemic.

Decreased mitochondrial DNA content in peripheral blood precedes the development of non-insulin-dependent diabetes mellitus

Qualitative changes in mitochondrial DNA (mtDNA), such as mutations and deletions, have been implicated in the pathogenesis of diabetes mellitus. In addition to the qualitative changes, mtDNA is subject to quantitative changes, and is vulnerable to oxidative stress, resulting in both qualitative and quantitative changes. This study was performed to investigate whether quantitative changes in mtDNA occur in non-insulin-dependent diabetes mellitus (NIDDM) patients and also in pre-diabetic subjects. MtDNA content from peripheral blood was measured by slot-blot analysis in 55 NIDDM patients and 29 age- and sex-matched control subjects. We have also analysed the mtDNA copies by quantitative polymerase chain reaction (PCR) method in 23 pre-diabetic subjects who converted to diabetic in 2 years and 22 age- and sex-matched control subjects who remained non-diabetic. Mean mtDNA quantity measured by slot blot method was 35% lower in patients with NIDDM than in control subjects (12.3+/-8.1 vs. 19.1+/-8.2 AU/microg DNA; P < 0.05). MtDNA quantities did not correlate with age, body mass index, duration of diabetes or HbA1c levels. We have also found that the mtDNA copies in subjects who converted to diabetes in 2 years were lower than in controls even before the development of diabetes (102.8+/-41.5 vs. 137.8+/-67.7 copies/pg template DNA P < 0.05). Inverse correlations were noted between mtDNA content and baseline waist hip circumference ratio (WHR) (r = -0.31, P < 0.05), and fasting glucose level (r = - 0.35, P < 0.05), diastolic blood pressure (r = -0.36, P < 0.05), and WHR (r = -0.40, P < 0.01) after development of diabetes. In conclusion, we demonstrate that the content of mtDNA decreases in peripheral blood of patients with NIDDM and the lower mtDNA levels precede the development of diabetes.

The prevalence of type 2 diabetes and gestational diabetes mellitus in an inner city multi-ethnic population

Zeeburg', a multiethnic town borough in the Amsterdam-East region, has one of the city's highest rates of immigrants. In the total population of 19,825 Surinam (mainly Creole), Turkish, Moroccan, and Dutch adults the prevalence of known type 2 diabetes in 1994 and of gestational diabetes mellitus (GDM) between January 1992 and January 1997 was investigated. Based on World Health Organization (WHO) criteria of 1985, the age-standardized prevalence of type 2 diabetes was similar in men (6.4%; 95% confidence interval [CI]: 5.6-7.2) and women (6.4%: 95% CI: 5.8-7.0) for all ethnic groups combined. However, the age- and sex-standardized prevalence of type 2 diabetes was significantly greater in the non-Dutch inhabitants than in the Dutch inhabitants (17.3% [95% CI: 12.9-21.6] in Surinam inhabitants, 10.9% [95% CI: 9.7-12.2] in Turkish inhabitants, 12.4% [95% CI: 9.7-15.0] in Moroccan inhabitants, and 3.6% [95% CI: 3.2-3.9] in Dutch inhabitants). The odds ratios for type 2 diabetes for the separate immigrant groups relative to the Dutch group were 5.88 (95% CI: 4.54-7.69) for Surinam inhabitants, 4.00 (95% CI: 2.86-5.55) for Turkish inhabitants, and 4.17 (95% CI: 3.03-5.55) for Moroccan inhabitants. GDM was present in 2.59% of women of non-Dutch origin compared with 0.62% of women of Dutch origin. A significant positive association was found between the non-Dutch origin and the occurrence of GDM (chi2 = 6.7; p < 0.01). The study highlights a high prevalence of known type 2 diabetes and GDM in the immigrant inhabitants and emphasizes that appropriate interventions are necessarily with implications for health targets and capitation based budgets.

Past and current obesity in Koreans with non-insulin-dependent diabetes mellitus

To determine the prevalence of past and current obesity among patients with non-insulin-dependent diabetes mellitus (NIDDM) and to define the clinical characteristics of non-obese NIDDM patients in South Korea, we studied a cross-section of 749 NIDDM patients and a group of age- and sex-matched control subjects. Current height, weight and waist-to-hip ratio (WHR), the history of weight changes and the family history of diabetes were recorded. Obesity was defined as body mass index (BMI) > 25 kg/m2. The maximum lifetime BMI of diabetic patients was significantly higher than that of control subjects (P < 0.001). Compared with control subjects, current BMI was higher in diabetic women (P < 0.001) but not in diabetic men. In contrast, WHR of both diabetic men and women were significantly higher than those of controls (P < 0.05). BMI and WHR correlated significantly with fasting C-peptide levels and log-triglyceride levels in NIDDM patients. As a whole, 72% of the South Korean NIDDM patients had a history of past obesity as assessed by their maximum weight, while only 38% of them were currently obese. Compared with obese patients, non-obese patients were characterized by lower fasting serum C-peptide levels (P < 0.001), a higher percentage of insulin treatment (P < 0.05), lower maximum BMI (P < 0.001) and more pronounced weight loss from the time at their maximum weight (P < 0.001). In summary, increased upper body adiposity and a history of past obesity were associated with NIDDM in South Korea. Although most South Korean NIDDM patients were previously obese, many of them were currently not obese. Lower maximum BMI, lower serum C-peptide levels and a higher percentage of insulin treatment in non-obese NIDDM patients suggest that the capacity to increase insulin secretion in response to increasing weight gain is rather limited in these patients.

Low prevalence of immunogenetic markers of IDDM in adult Koreans with diabetes detected on OGTT

In the Asian populations, it is not uncommon for adult patients with NIDDM to eventually lose beta-cell function and develop IDDM. Accepting that IDDM is an autoimmune disease, which occurs on a genetic background, it could by hypothesized that by measuring autoantibody prevalence and HLA DQ gene polymorphism, known important prediagnostic markers of IDDM, the prevalence of adult-onset IDDM in patients with previously undiagnosed NIDDM patients could be estimated. To do this, anti-GAD prevalence and HLA DQ A1 and DQ B1 polymorphisms after PCR amplification of genomic DNA were analyzed in 121 newly diagnosed diabetic patients of Yonchon cohort and compared to the results with those of 100 matched health control subjects. We also compared the results with those of other populations to assess the difference of genotype distribution. The overall prevalence of anti-GAD antibodies was 1.7% (2 of 121) in patients with previously undiagnosed NIDDM, whereas 1 of 100 controls had positive antibodies. Among those who were positive, their titer of antibodies to GAD were not high. No statistically significant differences in the distribution of either mean levels of anti-GAD or DQA1 and DQB1 alleles were found comparing NIDDM patients to controls. Interestingly, the frequency of DQB1*non-Asp-57 and DQA1*Arg-52 alleles in the Korean adult control population was similar to that of US Caucasians (DQB1*non-Asp-57: 0.431 vs. 0.475; DQA1*Arg-52: 0.492 vs. 0.463). The low prevalence of anti-GAD antibodies and HLA-DQA1 and DQB1 susceptibility alleles among recent-onset NIDDM patients, not different compared to controls suggests that diabetes in Korean adults is unlikely to have an autoimmune component to its pathogenesis.

Community-based epidemiologic study on atherosclerotic cardiovascular risk factors

The present study was undertaken to determine the prevalence of hyperlipidemia and to find out the possible impact of serum lipid profiles on other cardiovascular risk factors in Yonchon County, Korea. Population-based cross-sectional study by random cluster sampling of registered residents over 30 years of age was performed. Out of the 3804 subjects scheduled for the survey, 2520 underwent the actual examination. The prevalence of hypercholesterolemia (serum cholesterol > or = 240 mg/dl) was only 1.2%, whereas that of hypertriglyceridemia (serum triglyceride > or = 250 mg/dl) was as high as 11.3%. The serum levels of cholesterol, triglyceride and HDL cholesterol correlated with anthropometric indices, body mass indices and waist hip ratios. The prevalences of diabetes and/or hypertension increased as either serum cholesterol or triglyceride level increased. In addition, the prevalence rates of obesity, impaired glucose tolerance, hypertriglyceridemia and hypercholesterolemia in its isolated form (free of the others) were much lower than overall prevalence indicating an existence of major overlap among these cardiovascular atherosclerotic risk factors in the form of multiple combinations. Central obesity was found to be an independent associated factor for the aggregation of the conditions related to the increase in cardiovascular risks. The prevalence of hypercholesterolemia in Yonchon County was substantially lower than that previously suggested, albeit that of hypertriglyceridemia was very high. We could also observe a varying degree of transition in cardiovascular risks related to insulin resistance from the rural to the urban area with rapid emergence of non-communicable diseases as a result of modernization.