Metabolic and clinical characteristics of south Asians and Europeans in Coventry

Panethnic Differences in Blood Pressure in Europe: A Systematic Review and Meta-Analysis

BACKGROUND

People of Sub Saharan Africa (SSA) and South Asians(SA) ethnic minorities living in Europe have higher risk of stroke than native Europeans(EU). Study objective is to provide an assessment of gender specific absolute differences in office systolic(SBP) and diastolic(DBP) blood pressure(BP) levels between SSA, SA, and EU.

METHODS AND FINDINGS

We performed a systematic review and meta-analysis of observational studies conducted in Europe that examined BP in non-selected adult SSA, SA and EU subjects. Medline, PubMed, Embase, Web of Science, and Scopus were searched from their inception through January 31st 2015, for relevant articles. Outcome measures were mean SBP and DBP differences between minorities and EU, using a random effects model and tested for heterogeneity. Twenty-one studies involving 9,070 SSA, 18,421 SA, and 130,380 EU were included. Compared with EU, SSA had higher values of both SBP (3.38 mmHg, 95% CI 1.28 to 5.48 mmHg; and 6.00 mmHg, 95% CI 2.22 to 9.78 in men and women respectively) and DBP (3.29 mmHg, 95% CI 1.80 to 4.78; 5.35 mmHg, 95% CI 3.04 to 7.66). SA had lower SBP than EU(-4.57 mmHg, 95% CI -6.20 to -2.93; -2.97 mmHg, 95% CI -5.45 to -0.49) but similar DBP values. Meta-analysis by subgroup showed that SA originating from countries where Islam is the main religion had lower SBP and DBP values than EU. In multivariate meta-regression analyses, SBP difference between minorities and EU populations, was influenced by panethnicity and diabetes prevalence.

CONCLUSIONS

1) The higher BP in SSA is maintained over decades, suggesting limited efficacy of prevention strategies in such group in Europe;2) The lower BP in Muslim populations suggests that yet untapped lifestyle and behavioral habits may reveal advantages towards the development of hypertension;3) The additive effect of diabetes, emphasizes the need of new strategies for the control of hypertension in groups at high prevalence of diabetes.

Culturally appropriate health education for people in ethnic minority groups with type 2 diabetes mellitus

BACKGROUND

Ethnic minority groups in upper-middle-income and high-income countries tend to be socioeconomically disadvantaged and to have a higher prevalence of type 2 diabetes than is seen in the majority population.

OBJECTIVES

To assess the effectiveness of culturally appropriate health education for people in ethnic minority groups with type 2 diabetes mellitus.

SEARCH METHODS

A systematic literature search was performed of the following databases: The Cochrane Library, MEDLINE, EMBASE, PsycINFO, the Education Resources Information Center (ERIC) and Google Scholar, as well as reference lists of identified articles. The date of the last search was July 2013 for The Cochrane Library and September 2013 for all other databases. We contacted authors in the field and handsearched commonly encountered journals as well.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) of culturally appropriate health education for people over 16 years of age with type 2 diabetes mellitus from named ethnic minority groups residing in upper-middle-income or high-income countries.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. When disagreements arose regarding selection of papers for inclusion, two additional review authors were consulted for discussion. We contacted study authors to ask for additional information when data appeared to be missing or needed clarification.

MAIN RESULTS

A total of 33 trials (including 11 from the original 2008 review) involving 7453 participants were included in this review, with 28 trials providing suitable data for entry into meta-analysis. Although the interventions provided in these studies were very different from one study to another (participant numbers, duration of intervention, group versus individual intervention, setting), most of the studies were based on recognisable theoretical models, and we tried to be inclusive in considering the wide variety of available culturally appropriate health education.Glycaemic control (as measured by glycosylated haemoglobin A1c (HbA1c)) showed improvement following culturally appropriate health education at three months (mean difference (MD) -0.4% (95% confidence interval (CI) -0.5 to -0.2); 14 trials; 1442 participants; high-quality evidence) and at six months (MD -0.5% (95% CI -0.7 to -0.4); 14 trials; 1972 participants; high-quality evidence) post intervention compared with control groups who received 'usual care'. This control was sustained to a lesser extent at 12 months (MD -0.2% (95% CI -0.3 to -0.04); 9 trials; 1936 participants) and at 24 months (MD -0.3% (95% CI -0.6 to -0.1); 4 trials; 2268 participants; moderate-quality evidence) post intervention. Neutral effects on health-related quality of life measures were noted and there was a general lack of reporting of adverse events in most studies - the other two primary outcomes for this review. Knowledge scores showed improvement in the intervention group at three (standardised mean difference (SMD) 0.4 (95% CI 0.1 to 0.6), six (SMD 0.5 (95% CI 0.3 to 0.7)) and 12 months (SMD 0.4 (95% CI 0.1 to 0.6)) post intervention. A reduction in triglycerides of 24 mg/dL (95% CI -40 to -8) was observed at three months, but this was not sustained at six or 12 months. Neutral effects on total cholesterol, low-density lipoprotein (LDL) cholesterol or high-density lipoprotein (HDL) cholesterol were reported at any follow-up point. Other outcome measures (blood pressure, body mass index, self-efficacy and empowerment) also showed neutral effects compared with control groups. Data on the secondary outcomes of diabetic complications, mortality and health economics were lacking or were insufficient.Because of the nature of the intervention, participants and personnel delivering the intervention were rarely blinded, so the risk of performance bias was high. Also, subjective measures were assessed by participants who self-reported via questionnaires, leading to high bias in subjective outcome assessment.

AUTHORS' CONCLUSIONS

Culturally appropriate health education has short- to medium-term effects on glycaemic control and on knowledge of diabetes and healthy lifestyles. With this update (six years after the first publication of this review), a greater number of RCTs were reported to be of sufficient quality for inclusion in the review. None of these studies were long-term trials, and so clinically important long-term outcomes could not be studied. No studies included an economic analysis. The heterogeneity of the studies made subgroup comparisons difficult to interpret with confidence. Long-term, standardised, multi-centre RCTs are needed to compare different types and intensities of culturally appropriate health education within defined ethnic minority groups, as the medium-term effects could lead to clinically important health outcomes, if sustained.

Asian indians and insulin resistance syndrome: global perspective

Insulin resistance syndrome (IRS) is a crucial factor in causation of type 2 diabetes mellitus (T2DM) in Asian Indians. Approximately one-fifth of the migrant Asian Indians have evidence of metabolic syndrome. Furthermore, insulin resistance as estimated by homeostatic model assessment (HOMA-IR) was reported to be present in one-fifth of children and young adult Asian Indians with normal body mass index (BMI) and ~45-67% of those having high BMI. The cause(s) of such high prevalence of IRS in Asian Indians is not clear; however, inherent genetic predisposition, physical inactivity, excess regional body fat, and factors associated with migration may play an important role. It is important that lifestyle factor modification to prevent IRS and T2DM in Asian Indians should start in early childhood.

Adult-onset diabetes among Arabs and Jews in Israel: a population-based study

AIMS

To study the age at presentation and factors associated with adult-onset diabetes (≥ 20 years) among Arabs and Jews in Israel.

METHODS

Participants (n = 1100) were randomly selected from the urban population of the Hadera District in Israel. The study sample was stratified into equal groups according to sex, ethnicity (Arabs and Jews) and age. Information on age at diabetes presentation, family history of diabetes, history of gestational diabetes, socio-demographic and lifestyle characteristics was obtained through personal interviews. Self reports of diabetes were compared with medical records and were found reliable (κ = 0.87). The risk for diabetes was calculated using Kaplan-Meier survival analysis. Factors associated with diabetes in both ethnic groups were studied using Cox proportional hazard model.

RESULTS

The prevalence of adult-onset diabetes was 21% among Arabs and 12% among Jews. Arab participants were younger than Jews at diabetes presentation. By the age of 57 years, 25% of Arabs had diagnosed diabetes; the corresponding age among Jews was 68 years, a difference of 11 years (P < 0.001). The greater risk for diabetes among Arabs was independent of lifestyle factors, family history of diabetes and, among women, history of gestational diabetes; adjusted hazard ratio 1.70; 95% confidence interval 1.19-2.43.

CONCLUSIONS

Arabs in Israel are at greater risk for adult-onset diabetes than Jews and are younger at diabetes presentation. Culturally sensitive interventions aimed at maintaining normal body weight and active lifestyle should be targeted at this population. Possible genetic factors and gene-environmental interactions underlying the high risk for diabetes among Arabs should be investigated.

Support systems for and barriers to diabetes management in South Asians and Whites in the UK: qualitative study of patients' perspectives

OBJECTIVES

To explore experiences of UK-based South Asian and White patients with diabetes in relation to their support systems for and barriers to diabetes management.

DESIGN

Qualitative study (semistructured interviews analysed using a form of Interpretative Phenomenological Analysis).

PARTICIPANTS

20 outpatients with diabetes (12 British South Asians and 8 British Whites) with either good or poor glycaemic control.

SETTING

Hillingdon Hospital, Uxbridge, UK.

RESULTS

Qualitative analysis revealed distinct themes for the two ethnic groups. For the South Asian participants, challenges surrounding diet management and social stigma attached to having diabetes were the two predominant barriers to effective diabetes management. Support from immediate family members was commonly reported as a strong support system for optimising diabetes management by the South Asian sample in addition to the perceived positive impact of religion (healing power of prayer), the valuable informational support from their diabetes-care team, patient leaflets and diabetes magazines. Similar to the South Asians, adhering to dietary recommendations was the most difficult aspect of diabetes management for the White participants followed by the inconveniences surrounding injecting insulin. The hospital diabetes-care team was considered as the most effective support system for diabetes management by the White sample and interestingly, this was the only dominant theme in their reported sources of support.

CONCLUSIONS

Both South Asian and White participants emphasised adherence to dietary recommendations as the most difficult aspect of living with diabetes. In addition, social stigma attached to diabetes was a prominent concern among South Asian participants that seemed to have a significant negative impact on their diabetes control and overall management. Given South Asian patients' reliance on their family for the management of their condition, interventions targeting improved diabetes outcomes in this population may prove more successful if they are designed to involve significant family members.

GLUT4 gene polymorphisms and their association with type 2 diabetes in south Indians

BACKGROUND AND OBJECTIVES

The GLUT4 gene, which encodes glucose transporter 4, is a candidate gene for type 2 diabetes mellitus (T2DM). The aim of this study was to screen the GLUT4 gene for polymorphisms and to study association of such polymorphisms with T2DM in an Asian Indian population in southern India.

METHODS

The GLUT4 gene was sequenced in 25 normal glucose tolerance (NGT) and 25 T2DM subjects, and the variants found were then genotyped by polymerase chain reaction-restriction fragment length polymorphism in a pilot study population of 552 NGT and 643 T2DM subjects, randomly selected from the Chennai Urban Rural Epidemiology Study. Two of the variants (rs5435 and the novel variant), which showed significantly higher minor allele frequency in T2DM compared with NGT individuals in the pilot study population, were then retested with an additional 465 NGT and 363 T2DM subjects, giving a final sample size of 1,017 NGT and 1,006 T2DM subjects.

RESULTS

Sequencing of the GLUT4 gene revealed three known polymorphisms (rs5418, rs5421, and rs5435) and one novel T→G variant in the 3' untranslated region (UTR) at nucleotide position 6787483. The rs5418 and rs5421 polymorphisms did not show any association with diabetes. The rs5435 [Asn130Asn(C→T)] polymorphism was found to be associated with diabetes, with the odds ratio for the CT+TT genotype being 1.26 (95% confidence interval, 1.00-1.57; P=0.043) when the CC genotype was taken as reference. The frequency of the TG genotype of the novel 3'UTR T→G variant was significantly higher in diabetes subjects (1%) compared with NGT subjects (0.2%) (P=0.021). There was a significant difference in the proportion of the ACGT haplotype of the rs5418(A→G), rs5435(C→T), rs5421(C→G), and the T→G 3'UTR variant between the NGT (7.5%) and diabetes (5%) groups (P=0.003).

CONCLUSION

The rs5435 (C→T) polymorphism of the GLUT4 gene is associated with type 2 diabetes in this south Indian population.

Body size, body composition and fat distribution: comparative analysis of European, Maori, Pacific Island and Asian Indian adults

Although there is evidence that Asian Indians, Polynesians and Europeans differ in their body fat (BF)-BMI relationships, detailed comparative analysis of their underlying body composition and build characteristics is lacking. We investigated differences in the relationships between body fatness and BMI, fat distribution, muscularity, bone mineral mass, leg length and age-related changes in body composition between these ethnic groups. Cross-sectional analysis of 933 European, Maori, Pacific Island and Asian Indian adult volunteers was performed for total and percentage of BF, abdominal fat, thigh fat, appendicular muscle mass, bone mineral content and leg length measured by dual-energy X-ray absorptiometry. Asian Indian men and women (BMI of 24 and 26 kg/m2, respectively) had the same percentage of BF as Europeans with a BMI of 30 kg/m2 or Pacific men and women with BMI of 34 and 35 kg/m2, respectively. Asian Indians had more fat, both total and in the abdominal region, with less lean mass, skeletal muscle and bone mineral than all other ethnic groups. Leg length was relatively longer in Pacific men and Asian and Pacific women than in other ethnic groups. In Asian Indians, abdominal fat increased with increasing age, while the percentage of BF showed little change. In the other ethnic groups, both abdominal and total BF increased with age. In conclusion, ethnic differences in fat distribution, muscularity, bone mass and leg length may contribute to ethnic-specific relationships between body fatness and BMI. The use of universal BMI cut-off points may not be appropriate for the comparison of obesity prevalence between ethnic groups.

Culturally appropriate health education for type 2 diabetes mellitus in ethnic minority groups

BACKGROUND

Ethnic minority groups in upper-middle and high income countries tend to be socio-economically disadvantaged and to have higher prevalence of type 2 diabetes than the majority population.

OBJECTIVES

To assess the effectiveness of culturally appropriate diabetes health education on important outcome measures in type 2 diabetes.

SEARCH STRATEGY

We searched the The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, ERIC, SIGLE and reference lists of articles. We also contacted authors in the field and handsearched commonly encountered journals.

SELECTION CRITERIA

RCTs of culturally appropriate diabetes health education for people over 16 years with type 2 diabetes mellitus from named ethnic minority groups resident in upper-middle or high income countries.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Where there were disagreements in selection of papers for inclusion, all four authors discussed the studies. We contacted study authors for additional information when data appeared to be missing or needed clarification.

MAIN RESULTS

Eleven trials involving 1603 people were included, with ten trials providing suitable data for entry into meta-analysis. Glycaemic control (HbA1c), showed an improvement following culturally appropriate health education at three months (weight mean difference (WMD) - 0.3%, 95% CI -0.6 to -0.01), and at six months (WMD -0.6%, 95% CI -0.9 to -0.4), compared with control groups who received 'usual care'. This effect was not significant at 12 months post intervention (WMD -0.1%, 95% CI -0.4 to 0.2). Knowledge scores also improved in the intervention groups at three months (standardised mean difference (SMD) 0.6, 95% CI 0.4 to 0.7), six months (SMD 0.5, 95% CI 0.3 to 0.7) and twelve months (SMD 0.4, 95% CI 0.1 to 0.6) post intervention. Other outcome measures both clinical (such as lipid levels, and blood pressure) and patient centred (quality of life measures, attitude scores and measures of patient empowerment and self-efficacy) showed no significant improvement compared with control groups.

AUTHORS' CONCLUSIONS

Culturally appropriate diabetes health education appears to have short term effects on glycaemic control and knowledge of diabetes and healthy lifestyles. None of the studies were long-term, and so clinically important long-term outcomes could not be studied. No studies included an economic analysis. The heterogeneity of studies made subgroup comparisons difficult to interpret with confidence. There is a need for long-term, standardised multi-centre RCTs that compare different types and intensities of culturally appropriate health education within defined ethnic minority groups.

Obesity and intermediate clinical outcomes in diabetes: evidence of a differential relationship across ethnic groups

AIM

To examine associations between obesity, ethnicity and intermediate clinical outcomes in diabetes.

METHODS

Population-based, cross-sectional study using electronic primary care medical records of 7300 people with diabetes from White, Black and south Asian ethnic groups.

RESULTS

The pattern of obesity differed within ethnic groups, with rates significantly higher in younger when compared to older Black (women, 63% vs. 44%, P = 0.002; men, 37% vs. 20%, P = 0.005) and south Asian (women, 47% vs. 27%, P = 0.01; men, 21% vs. 13%, P = 0.05) people. Obese people with diabetes were significantly less likely to achieve an established target for blood pressure control (adjusted odds ratio 0.50, 95% confidence interval 0.42, 0.59). Differences in mean systolic blood pressure in obese and normal weight persons were significant in the White group but not in the Black groups or south Asian groups (6.9 mmHg, 1.9 mmHg and 2.7 mmHg, respectively). Differences in mean diastolic blood pressure between obese and normal weight persons were 4.8 mmHg, 3.6 mmHg and 3.4 mmHg in the White, Black and south Asian groups. Mean HbA(1c) and achievement of an established treatment target did not differ significantly with obesity in any ethnic group.

CONCLUSIONS

Obesity is more prevalent amongst younger people than older people with diabetes in ethnic minority groups. The relationship between obesity and blood pressure control in diabetes differs markedly across ethnic groups. Major efforts must be implemented, especially in young people, to reduce levels of obesity in diabetes and improve long-term outcomes.

The G1057D polymorphism of IRS-2 gene and its relationship with obesity in conferring susceptibility to type 2 diabetes in Asian Indians

OBJECTIVE

To investigate the association of insulin receptor substrate-2 (IRS-2) G1057D polymorphism with type 2 diabetes and obesity in Asian Indians.

METHODS

The study comprised of 1193 normal glucose tolerant (NGT) subjects and 1018 subjects with type 2 diabetes, aged >/=20 years with an average body mass index of 23.7+/-4.6 and 25.3+/-4.2 kg/m(2), respectively. The subjects were unrelated and randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), a population-based study in Chennai in southern India. The G1057D polymorphism of the IRS-2 gene was genotyped using PCR-RFLP assay.

RESULTS

The genotype frequency of the IRS-2 G1057D polymorphism was significantly different between the NGT and type 2 diabetic groups (P=0.0007) in the total study subjects and among the obese subjects (P=0.00007). Logistic regression analysis showed that the DD genotype showed an increased susceptibility to diabetes with an odds ratio (adjusted for age and sex) of 2.19 (95% CI: 1.34-3.57, P=0.002) when compared to the GG+GD genotype, among the obese subjects, but not in non obese subjects. In order to explore possible interaction with obesity, logistic regression analysis was performed and the coefficient corresponding to the interaction parameter (genotype x obesity) was significant (P=0.0001).

CONCLUSION

In Asian Indians, the DD genotype increases susceptibility to type 2 diabetes by interacting with obesity.

Peroxisome proliferator-activated receptor-gamma co-activator-1alpha (PGC-1alpha) gene polymorphisms and their relationship to Type 2 diabetes in Asian Indians

AIMS

The objective of the present investigation was to examine the relationship of three polymorphisms, Thr394Thr, Gly482Ser and +A2962G, of the peroxisome proliferator activated receptor-gamma co-activator-1 alpha (PGC-1alpha) gene with Type 2 diabetes in Asian Indians.

METHODS

The study group comprised 515 Type 2 diabetic and 882 normal glucose tolerant subjects chosen from the Chennai Urban Rural Epidemiology Study, an ongoing population-based study in southern India. The three polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Haplotype frequencies were estimated using an expectation-maximization (EM) algorithm. Linkage disequilibrium was estimated from the estimates of haplotypic frequencies.

RESULTS

The three polymorphisms studied were not in linkage disequilibrium. With respect to the Thr394Thr polymorphism, 20% of the Type 2 diabetic patients (103/515) had the GA genotype compared with 12% of the normal glucose tolerance (NGT) subjects (108/882) (P = 0.0004). The frequency of the A allele was also higher in Type 2 diabetic subjects (0.11) compared with NGT subjects (0.07) (P = 0.002). Regression analysis revealed the odds ratio for Type 2 diabetes for the susceptible genotype (XA) to be 1.683 (95% confidence intervals: 1.264-2.241, P = 0.0004). Age adjusted glycated haemoglobin (P = 0.003), serum cholesterol (P = 0.001) and low-density lipoprotein (LDL) cholesterol (P = 0.001) levels and systolic blood pressure (P = 0.001) were higher in the NGT subjects with the XA genotype compared with GG genotype. There were no differences in genotype or allelic distribution between the Type 2 diabetic and NGT subjects with respect to the Gly482Ser and +A2962G polymorphisms.

CONCLUSIONS

The A allele of Thr394Thr (G --> A) polymorphism of the PGC-1 gene is associated with Type 2 diabetes in Asian Indian subjects and the XA genotype confers 1.6 times higher risk for Type 2 diabetes compared with the GG genotype in this population.

Foot ulcer risk is lower in South-Asian and african-Caribbean compared with European diabetic patients in the U.K.: the North-West diabetes foot care study

OBJECTIVE

To determine 1) foot ulcer rates for European, South-Asian, and African-Caribbean diabetic patients in the U.K and 2) the contribution of neuropathy and peripheral arterial disease (PAD) differences to altered ulcer risk between the groups.

RESEARCH DESIGN AND METHODS

In this U.K. population-based study, we screened 15,692 type 1 and type 2 diabetic patients in the community health care setting for foot ulcers, foot deformities, neuropathy, and PAD plus other characteristics. In total, 13,409 were European (85.5%), 1,866 were South Asian (11.9%), and 371 were African Caribbean (2.4%).

RESULTS

The age-adjusted prevalence of diabetic foot ulcers (past or present) for Europeans, South Asians, and African Caribbeans was 5.5, 1.8, and 2.7%, respectively (P < 0.0001). Asians and African Caribbeans had less neuropathy, PAD, and foot deformities than Europeans (P = 0.003). The unadjusted risk of ulcer (odds ratio [OR]) for Asians versus Europeans was 0.29 (95% CI 0.20-0.41) (P < 0.0001). PAD, neuropathy, foot deformities, and insulin use attenuated the age-adjusted OR from 0.32 to 0.52 (0.35-0.76) (P < 0.0001). African-Caribbean versus European ulcer risk in males was attenuated from 0.60 to 0.71 by vibration sensation.

CONCLUSIONS

South Asians with diabetes in the U.K. have about one-third the risk of foot ulcers of Europeans. The lower levels of PAD, neuropathy, insulin usage, and foot deformities of the Asians account for approximately half of this reduced foot ulcer risk. Lower neuropathy is the main contributor to the reduced African-Caribbean ulcer rate, particularly in men. The reasons for these ethnic differences warrant further investigation.

A population-based study of the association between areca nut chewing and type 2 diabetes mellitus in men (Keelung Community-based Integrated Screening programme No. 2)

AIMS/HYPOTHESIS

The aim of this study was to assess whether the diabetogenicity of areca nut (Areca catechu or 'betel-nut'), which has previously been demonstrated experimentally in mice, independently contributes to the risk of hyperglycaemia or type 2 diabetes in men in Taiwan, where the habit has become established relatively recently.

METHODS

We used data from a population-based cross-sectional survey and a multiple-disease-screening programme that tested for hyperglycaemia, type 2 diabetes and risk factors related to type 2 diabetes. Data on habitual areca nut chewing were available for 14,816 men. Multiple logistic regression models were used to determine whether areca nut chewing was an independent risk factor for type 2 diabetes.

RESULTS

Compared with non-chewers, areca nut chewers had higher age-adjusted prevalence rates for hyperglycaemia (11.4% vs 8.7%) and type 2 diabetes (10.3% vs 7.8%). Areca nut chewing independently increased the risk of hyperglycaemia (adjusted odds ratio [OR] 1.19, 95% CI 0.97-1.45) and type 2 diabetes (adjusted OR 1.29, 95% CI 1.04-1.60). The independent effects of duration of chewing were dose-dependent for type 2 diabetes (adjusted OR 1.32 for the duration of 10-19 years and 1.41 for the duration of > or =20 years), as were the effects of increased rates of areca nut chewing (adjusted OR 1.14 for <10 pieces/day, 1.30 for 10-19 pieces/day and 2.02 for > or =20 pieces/day); similar findings were noted for hyperglycaemia.

CONCLUSIONS/INTERPRETATION

The habit of chewing areca nut independently contributes to the risk of both hyperglycaemia and type 2 diabetes in Taiwanese men. This association is dose-dependent with respect to the duration of areca nut use and the quantity of areca nut chewed per day.

Insulin resistance syndrome (metabolic syndrome) and obesity in Asian Indians: evidence and implications

OBJECTIVES

This review describes prevalence, determinants, and possible pathophysiologic mechanisms and suggests management and research directions for insulin resistance syndrome (metabolic syndrome) in Asian Indians.

METHOD

We reviewed the topic using the terms Asian Indians, Asians, South Asians, and Indians coupled with the terms insulin resistance, hyperinsulinemia, metabolic syndrome, and obesity from the databases Pubmed (National Library of Medicine, Bethesda, MD, USA) and Current Contents (Institute for Scientific Information, Thomson Scientific, Philadelphia, PA, USA) and from non-indexed publications of the medical research and governmental institutions in India.

RESULTS

Asian Indians have a high prevalence of insulin resistance syndrome that may underlie their greater than normal tendency to develop diabetes mellitus and early atherosclerosis. Important reasons could be their excess body fat and adverse body fat patterning including abdominal adiposity even when the body mass index is within the currently defined normal limits. Some of these features have been reported at birth and childhood. Whether Asian Indians also have tendency to develop insulin resistance de novo, independent of total or regional adiposity, needs further investigation. Underlying genetic tendency or early-life adverse events may contribute to such a phenotype, but lifestyle factors alone or modulated by inherited factors appear to play an important role because obesity and dyslipidemia become worse with urbanization and migration. Systemic stress may contribute to insulin resistance syndrome in the intra-country and inter-country migrant Asian Indians.

CONCLUSIONS

High prevalences of excess body fat, adverse body fat patterning, hypertriglyceridemia, and insulin resistance beginning at a young age have been consistently recorded in Asian Indians irrespective of their geographic locations. These data suggest that primary prevention strategies should be initiated early in this ethnic group.

Differences in the process of diabetic care between south Asian and white patients in inner-city practices in Nottingham, UK

The prevalence and complication rate of diabetes is higher amongst British south Asians when compared to the rest of the adult population. There is some evidence to suggest that there are differences in access to healthcare in the UK for different ethnic groups, but there has been little research examining differences in processes of care between ethnic groups and place of delivery of diabetic care. The present study was a retrospective, multi-practice audit exploring differences in the processes of diabetic care provided to white and south Asian patients. Data were obtained from eight practices located in deprived areas in Nottingham, UK. A review of the evidence-based protocols for the monitoring of diabetic care generated a list of process criteria to be measured. All primary care data sources were examined over a 12-month period by a single investigator. The data were analysed with respect to patient ethnicity and place of diabetic care after adjusting for confounders. Eight hundred and thirty-nine diabetic patients were included in the audit and 671 (80.0%) received a formal annual diabetic review. One hundred and five (12.5%) patients were classified as south Asian. They were significantly less likely to have their blood pressure [86% versus 89%, odds ratio (OR) = 0.62, 95% confidence interval (95% CI) = 0.54-0.72] or serum creatinine (67% versus 76%, OR = 0.41, 95% CI = 0.32-0.52) measured when compared to white patients. Patients receiving shared care from a hospital-based diabetic team were more likely to have a range of items of the annual review recorded. When examined by ethnicity, south Asians receiving shared care were again less likely than white patients to have their blood pressure and serum creatinine measured. There was also some evidence that they may be less likely to have their body mass index recorded and their feet examined. The findings of the present study showed that, although most diabetic patients received a formal annual clinical review, scope for improvement remained. Shared care of patients with a hospital-based team produced better results when processes of care were examined. However, this benefit did not apply equally to south Asian and white patients. Further studies are indicated to confirm these results, which may have wider implications for the planning and provision of diabetic care.

The associations of body mass index, C-peptide and metabolic status in Chinese Type 2 diabetic patients

BACKGROUND

Chinese Type 2 diabetic subjects are generally less obese than their Caucasian counterparts. We hypothesized that lean and obese Chinese Type 2 diabetic subjects have different metabolic and insulin secretory profiles. We compared the clinical features, C peptide and metabolic status between lean/normal weight and obese diabetic subjects.

STUDY DESIGN

We conducted a cross-sectional study on 521 consecutive diabetic subjects newly referred to a Diabetes Clinic in 1996. The subjects were categorized into underweight (< 18.5 kg/m(2)), normal weight (18.5-23 kg/m(2)) and overweight (>/= 23 kg/m(2)) according to the re-defined WHO criterion for obesity in Asia Pacific Region. Metabolic and anthropometric parameters were compared between groups with different levels of obesity.

RESULTS

In this cohort, 5.8, 30.6 and 63.7% of subjects were underweight, normal weight and overweight, respectively, using the 'Asian' criteria. Of these 521 subjects, 20% had fasting C-peptide less than 0.2 nmol/l, suggesting insulin deficiency. Fasting C-peptide showed linear increasing trend (P < 0.001) while HbA(1c) showed decreasing trend (P = 0.001) with BMI after adjustment for duration of disease. There were more subjects in the underweight group who were treated with insulin (41.3% vs. 13.9 and 8.2%, P < 0.001). Although homeostasis model assessment was similar amongst the three groups, systolic (P = 0.006) and diastolic blood pressure (P < 0.001) and triglyceride (P < 0.001) showed increasing, while HDL-C (P < 0.001) showed decreasing, trends across different BMI groups. The underweight patients had the lowest C-peptide and highest HbA(1c) while overweight patients had the highest C-peptide, blood pressure, triglyceride but lowest HbA(1c) levels.

CONCLUSION

In Chinese Type 2 diabetic patients, lean subjects had predominant insulin deficiency and obese subjects had features of metabolic syndrome. Clinicians should have low threshold to initiate insulin therapy in lean Type 2 diabetic patients with suboptimal glycaemic control. In obese diabetic patients, aggressive control of multiple cardiovascular risks is of particular importance.

Fetal overnutrition in polynesian pregnancies and in gestational diabetes may lead to dysregulation of the adipoinsular axis in offspring

OBJECTIVE

To compare umbilical cord leptin concentrations in different ethnic groups and between pregnancies with and without gestational diabetes mellitus (GDM) in Auckland, New Zealand.

RESEARCH DESIGN AND METHODS

A cross-sectional study of 116 European, Polynesian, and South Asian women and their infants with and without GDM. Maternal metabolic measures were recorded at 36 weeks' gestation, umbilical cord samples were collected at birth, and neonatal anthropometric measures were recorded 24 h after delivery.

RESULTS

Compared with Europeans and South Asians, samples of Polynesian umbilical cords had higher leptin concentrations (8.7 and 9.5 vs. 14.9 ng/ml, respectively; P = 0.026). Umbilical cord samples from pregnancies complicated by GDM had higher leptin concentrations than those from normal pregnancies (22.3 vs. 13.8 ng/ml, respectively; P = 0.022). Maternal leptin concentrations at 36 weeks were similar across ethnic groups and with and without GDM. Cord leptin correlated with birth weight, measures of fetal size, and cord insulin in normal pregnancies and those complicated by GDM. In multivariate analyses, cord leptin was related to birth weight (P < 0.001), gestation at delivery (P = 0.038), and ethnic group (P = 0.017) in normal pregnancies and to birth weight (P < 0.001), gestation at delivery (P < 0.001), and sex (P = 0.003) but not maternal diabetes status (P = 0.909) in pregnancies complicated by GDM.

CONCLUSIONS

Offspring of Polynesian women are relatively hyperleptinemic, independent of birth size. Offspring of women with GDM are also relatively hyperleptinemic at birth, but this was associated with their increased birth weight. We speculate that this GDM-associated relative hyperleptinemia may be due to fuel-mediated teratogenesis affecting the adipoinsular axis, which in turn could also lead to leptin resistance and obesity in adult life. The reason for the ethnic difference in hyperleptinemia is unclear.

Polynesians: prone to obesity and Type 2 diabetes mellitus but not hyperinsulinaemia

AIMS

To compare the extent of hyperinsulinaemia among New Zealand Europeans and Polynesians (an ethnic group at high risk of Type 2 diabetes mellitus).

METHODS

A cross-sectional survey from randomly selected households was conducted in inner urban South Auckland. Subjects were either European, Maori or Pacific Islands Polynesians aged 40-79 years and were screened for diabetes using a random blood glucose. Those with an elevated result, and 20% randomly selected from those with a normal screening result, were invited to a 75-g glucose tolerance test. WHO criteria (1998) for diabetes were used.

RESULTS

In those aged 40-59 years, total prevalence of diabetes was 7.5 (6.2-9.0)% in Europeans but 21.1 (16.6-25.6)% among Maori and 25.0 (19.8-30.1)% among Pacific peoples; obesity (body mass index >or= 31.0 kg/m2) was present in 26% Europeans, 63% Maori and 69% Pacific peoples. Non-diabetic Polynesians were relatively hyperglycaemic and hyperinsulinaemic. After adjusting for the degree of obesity, Polynesians had similar insulin levels to Europeans.

CONCLUSIONS

These findings indicate that Polynesians are not intrinsically insulin resistant as a group, a prerequisite found in most other ethnic groups at high risk of Type 2 diabetes mellitus. The high prevalence of Type 2 diabetes in Polynesians could be the result of their high prevalence of obesity.

Ethnicity and risk factors for coronary heart disease in diabetes mellitus

INTRODUCTION

The Framingham equation can be used to predict the risk of coronary heart disease (CHD) and so to target risk factor intervention. Reservations have been applied to its use in south Asian populations since the high CHD mortality in this group may not be accounted for by traditional risk factors.

METHODS

We applied the Framingham equation to 1826 patients with diabetes of whom 1215 were of white Caucasian and 611 south Asian origin. Having calculated the 10-year CHD risks the contribution of risk factors were compared between ethnic groups.

RESULTS

Mean 10-year CHD risk was the same in the two ethnic groups (20.7 vs. 21.5%, white Caucasian vs. south Asian men and 16.5 vs. 15.9%, white Caucasian vs. south Asian women). However, the risk factor profile was different between the two groups. Mean total cholesterol was lower in south Asians (5.23 vs. 5.41 mmol/l, south Asian vs. white Caucasian men (p = 0.01) and 5.38 vs. 5.68 mmol/l, south Asian vs. white Caucasian women (p < 0.001)). HDL cholesterol levels were also lower (median HDL cholesterol 0.94 vs. 1.11 mmol/l, south Asian vs. white Caucasian men (p < 0.001) and 1.07 vs. 1.3 mmol/l, south Asian vs. white Caucasian women (p < 0.0001)) leading to higher total: HDL cholesterol ratios (5.48 vs. 4.78, south Asian vs. white Caucasian men (p = 0.032) and 4.91 vs. 4.26, south Asian vs. white Caucasian women (p < 0.001).

CONCLUSION

Calculated 10-year CHD risks are the same in south Asian and white Caucasian diabetic patients but the factors contributing to this risk differ. Different management of these risk factors may account for the higher mortality from CHD in those of south Asian origin.

Dietary practices among Europeans and different South Asian groups in Coventry

The dietary customs of people of South Asian origin living in Britain are important determinants of health but have been relatively little studied. As part of the Coventry study of diabetes carried out in the Foleshill ward of the city, subjects undergoing oral glucose tolerance tests provided information on this aspect of lifestyle. A questionnaire was completed by all of the last 612 subjects undergoing testing. These included 304 of European origin, 118 Punjabi Sikhs, seventy-six Pakistani/Punjabi Moslems, twenty-eight Gujerati Moslems, twenty-five Punjabi Hindus and forty-seven Gujerati Hindus. There were no discernible differences in the dietary customs of those with normal glucose tolerance, impaired glucose tolerance and newly diagnosed diabetes. Subjects of South Asian origin ate significantly fewer meals per day than European subjects. Evening meal times were 2-3 h later among South Asians. Europeans ate less fruit but more vegetables and more brown rice than South Asians. Gujeratis ate more rice, fried snacks and white flour. Moslems were least likely to be vegetarians, to drink alcohol and to use home-made ghee and yoghurt, and Punjabi Sikhs and Hindus ate dhal more frequently than Pakistani Moslems, Gujerati Moslems or Hindus. Most South Asians ate Indian sweets and 'Western' snacks.

Diabetes care in South Asian and white European patients with type 2 diabetes

Aspects of diabetes care in South Asian and white European patients with Type 2 diabetes attending a hospital review clinic were explored. Among the clinic population of 1710 patients, 258 (15%) were of South Asian origin. A significantly greater proportion (95% CI for difference in proportions 8-22%) of these patients was treated with oral hypoglycaemic drugs than in white Europeans, in whom there was a correspondingly greater proportion receiving insulin treatment. In a case-control study, where 154 patients in each racial group were stratified according to treatment regimen, significantly more South Asian patients (13/30 vs 6/30, p < 0.05) on insulin were treated with a once-daily regimen. Despite these observed differences in treatment of diabetes, glycaemic control was no worse in South Asian patients when compared to their white European counterparts. South Asian diabetic patients attending hospital diabetes clinics in the UK can experience similar levels of glycaemic control to white Europeans.

Increased secretion of 32,33 split proinsulin after intravenous glucose in glucose-tolerant first-degree relatives of patients with non-insulin dependent diabetes of European, but not Asian, origin

OBJECTIVE

The aetiology of non-insulin dependent diabetes is unknown, but defective insulin secretion is a feature. The disease also has a strong genetic basis and first-degree relatives of patients have an increased risk of future diabetes. To investigate whether beta-cell dysfunction is an early feature of the disease, we studied insulin secretion in healthy first-degree relatives of patients with non-insulin dependent diabetes.

DESIGN

Each subject underwent a 1-hour intravenous glucose tolerance test (0.3 g/kg).

PATIENTS

Seventeen first-degree relatives of patients (10 of European and 7 of Asian (Indian subcontinent) origin) with normal glucose tolerance were compared with 17 matched control subjects with no family history of diabetes.

MEASUREMENTS

Plasma immunoreactive insulin (IRI) was measured by radioimmunoassay, and specific insulin, intact and 32,33 split proinsulin were measured by specific immunoradiometric assays (IRMA) for the 1st phase (0-10 minutes) and 2nd phase (10-60 minutes) responses. Glucose and intermediary metabolites were measured enzymatically.

RESULTS

Fasting concentrations of IRI, IRMA insulin, intact and 32,33 split proinsulin were similar in relatives and controls in each group. Fasting glucose levels were similar in European relatives and controls but lower in Asian relatives compared to their controls (mean +/- SE 4.9 +/- 0.2 vs 5.5 +/- 0.2 mmol/l, P < 0.05). Following intravenous glucose, European relatives had similar IRI and glucose levels to their controls. Secretion of 32,33 split proinsulin was increased in European relatives compared to their controls, significantly so for 2nd phase secretion (1st phase median (range): 71 (7-352) vs 55 (17-118) pmol/l min, NS; 2nd phase: 433 (115-1459) vs 234 (55-745) pmol/l min, P < 0.05). Secretion of IRMA insulin and intact proinsulin were similar in European relatives and controls (IRMA insulin: 1st phase 2757 (700-10,969) vs 2830 (632-4682) pmol/l min; 2nd phase 6387 (3006-15,865) vs 5284 (2060-18,605) pmol/l min; intact proinsulin: 1st phase 31 (13-113) vs 32 (16-72) pmol/l min; 2nd phase: 174 (87-737) vs 159 (97-298) pmol/l min). European relatives had a greater percentage of proinsulin-like molecules (intact + 32,33 split proinsulin) to total insulin (sum of IRMA insulin + intact + 32,33 split proinsulin) during the 2nd phase of secretion (9.1 (5.0-11.8) vs 5.9 (4.3-12.6)%, P < 0.05). In contrast, Asian relatives had similar secretion of IRI, IRMA insulin, intact and 32,33 split proinsulin to their controls. Glucose disappearance (KG) was similar in relatives and controls within each ethnic group (Europeans: relatives 725 +/- 101 vs controls 668 +/- 47/min; Asian: relatives 610 +/- 97 vs controls 783 +/- 936/min). Asian relatives had higher fasting circulating glycerol (65 +/- 7 vs 44 +/- 4 mumol/l, P < 0.05), non-esterified fatty acid (569 +/- 59 vs 375 +/- 64 mumol/l, P < 0.05) and 3-hydroxybutyrate levels (147 (44-187) vs 35 (21-57) mumol/l, P < 0.01) than their controls and this persisted following intravenous glucose. This difference was not observed in the European group.

CONCLUSION

First-degree relatives of European patients with NIDDM possess early signs of beta-cell dysfunction, with increased and disproportionate secretion of 32,33 split proinsulin after intravenous glucose, whilst glucose tolerance is still normal.

Serum lipoprotein levels and plasma concentrations of insulin, intact and 32, 33 split proinsulin in normoglycaemic relatives of patients with type 2 diabetes

Type 2 diabetes is associated with abnormal lipoprotein levels and altered plasma concentrations of insulin, intact and 32, 33 split proinsulin. To investigate whether these are early features of the disease, we studied 36 normoglycaemic first-degree relatives of patients with Type 2 diabetes (13 European, 15 of Asian (Indian-subcontinent), and 8 of Afro-Caribbean origin) and 36 control subjects with no family history of diabetes. Relatives and controls were matched for age (mean +/- S.E. 33 +/- 2 vs 34 +/- 2 years), body mass index (23.7 +/- 0.5 vs 23.7 +/- 0.6 kg m-2), sex (17 M, 19 F) and ethnic origin. After an overnight fast, blood was sampled for measurement of serum lipids, plasma glucose and insulin, intact and 32, 33 split proinsulin by specific immunoradiometric assays. Relatives and controls had similar fasting concentrations of glucose (5.0 +/- 0.1 vs 4.9 +/- 0.1 mmol l-1), total cholesterol (4.51 +/- 0.13 vs 4.54 +/- 0.17 mmol l-1), HDL-cholesterol (1.21 +/- 0.06 vs 1.10 +/- 0.05 mmol l-1), LDL-cholesterol (2.84 +/- 0.14 vs 2.96 +/- 0.14 mmol l-1) and triglyceride (median (range) 0.78 (0.44-2.45) vs 0.83 (0.41-4.03) mmol l-1). Fasting levels of insulin (50.4 (18.9-174.0) vs 51.6 (10.0-118.0) pmol l-1, intact proinsulin (2.8 (0.1-15.0) vs 2.1 (0.6-6.4) pmol l-1 and 32, 33 split proinsulin (2.0(0-23.7) vs 1.6 (0.3-6.0) pmol l-1) were not significantly different between relatives and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences in umbilical cord insulin and birth weight in non-diabetic pregnancies of women from different ethnic groups in New Zealand

Many ethnic groups at high risk of non-insulin-dependent diabetes mellitus are hyperinsulinaemic by early adult life. This study assessed whether such hyperinsulinaemia is present at birth. Cross sectional comparisons of maternal biochemistry, umbilical cord biochemistry and neonatal anthropometry were made between one 'low risk' and three 'high risk' ethnic groups, without diabetes in pregnancy in Auckland, New Zealand. The study comprised 123 European, Polynesian (Maori and Pacific Islands) and Indian normal pregnancies. Indian mothers were the smallest, with the highest insulin and non-esterified fatty acid concentrations. Polynesian mothers were the most obese with a higher fructosamine concentration. From these pregnancies, Indian neonates were smaller, slimmer, with the highest cord triglyceride (0.6 mmol/l vs 0.4 mmol/l, p < 0.01), and lowest cord insulin concentrations (7.1 mU/l vs 8.6 mU/l (European), 9.2 mU/l (Polynesian), p < 0.05). Polynesian babies had a high cord insulin: C-peptide ratio (52.5 mU/nmol vs 44.4 mU/nmol (European), 44.1 mU/nmol (Indian), p = 0.05). Although reduced intrauterine growth may contribute to the excess of diabetes and heart disease in Indians, it cannot explain the excess of diabetes in Polynesians. Exposure to minor relative maternal hyperglycaemia in the mother and abnormal neonatal insulin handling (as demonstrated by the higher insulin: C-peptide ratio) may be of long-term significance in Polynesians.