Risk prediction models for the development of diabetes in Mauritian Indians.

AIMS: To develop risk prediction models of future diabetes in Mauritian Indians. METHODS: Three thousand and ninety-four Mauritian Indians (1141 men, aged 20-65 years) without diabetes in 1987 or 1992 were followed up to 1992 or 1998. Subjects underwent repeated oral glucose tolerance tests and diabetes was diagnosed according to 2006 World Health Organization/International Diabetes Federation criteria. Cox regression models for interval censored data were performed using data from 1544 randomly selected participants. Predicted probabilities for diabetes were calculated and validated in the remaining 1550 subjects. RESULTS: Over 11 years of follow-up, there were 511 cases of diabetes. Among variables tested, family history of diabetes, obesity (body mass index, waist circumference) and glucose were significant predictors of diabetes. Predicted probabilities derived from a simple model fitted with sex, family history of diabetes and obesity ranged from 0.05 to 0.64 in men and 0.03 to 0.49 in women. To predict the onset of diabetes, area under the receiver operating characteristic (ROC) curve (AROC) of predicted probabilities was 0.62 (95% confidence interval, 0.56-0.68) in men and 0.64 (0.59-0.69) in women. At a cut-off point of 0.12, the sensitivity and specificity were 0.72 (0.71-0.74) and 0.47 (0.45-0.49) in men and 0.77 (0.75-0.78) and 0.50 (0.48-0.52) in women, respectively. Addition of fasting plasma glucose (FPG) to the model improved the prediction slightly [AROC curve 0.70 (0.65-0.76) in men, 0.71 (0.67-0.76) in women]. CONCLUSIONS: A diabetes prediction model based on obesity and family history yielded moderate discrimination in Mauritian Indians, which was slightly inferior to the model with the FPG but may be useful in low-income countries to promote identification of people at high risk of diabetes.

The metabolic syndrome as a predictor of incident diabetes mellitus in Mauritius.

AIMS: To assess the utility of the metabolic syndrome (MetS) and a Diabetes Predicting Model as predictors of incident diabetes. METHODS: A longitudinal survey was conducted in Mauritius in 1987 (n = 4972; response 80%) and 1992 (n = 3685; follow-up 74.2%). Diabetes status was retrospectively determined using 1999 World Health Organization (WHO) criteria. MetS was determined according to four definitions and sensitivity, positive predictive value (PPV), specificity and the association with incident diabetes before and after adjustment for MetS components calculated. RESULTS: Of the 3198 at risk, 297 (9.2%) developed diabetes between 1987 and 1992. The WHO MetS definition had the highest prevalence (20.3%), sensitivity (42.1%) and PPV (26.8%) for prediction of incident diabetes, the strongest association with incident diabetes after adjustment for age and sex [odds ratio 4.6 (3.5-6.0)] and was the only definition to show a significant association after adjustment for its component parts (in men only). The low prevalence and sensitivity of the International Diabetes Federation (IDF) and ATPIII MetS definitions resulted from waist circumference cut-points that were high for this population, particularly in men, and both were not superior to a diabetes predicting model on receiver operating characteristic analysis. CONCLUSIONS: Of the MetS definitions tested, the WHO definition best identifies those who go on to develop diabetes, but is not often used in clinical practice. If cut-points or measures of obesity appropriate for this population were used, the IDF and ATPIII MetS definitions could be recommended as useful tools for prediction of diabetes, given their relative simplicity.

Leptin predicts the development of diabetes in Mauritian men, but not women: a population-based study.

OBJECTIVE: To determine if levels of the adipocyte-derived hormone, leptin, predict the development of type 2 diabetes. METHODS: Population-based surveys were undertaken in the multiethnic nation of Mauritius in 1987, 1992 and 1998. Questionnaires, anthropometric measurements, and a 2-h 75-g oral glucose tolerance test were included. A cohort of 2330 participants who were free of diabetes, aged 25-79 years in 1987, and who were followed-up in 1992 and 1998 was studied. Serum leptin was measured in baseline samples. Glucose tolerance was classified according to WHO (World Health Organization) 1999 criteria. RESULTS: In total, 456 subjects developed diabetes over 11 years with similar incidences in all ethnic groups (P=0.2). Baseline leptin correlated positively with anthropometric measurements, fasting and postload insulin and homeostasis model assessment indices (all P<0.001), and inversely with subsequent weight increase. Participants with incident diabetes had higher serum levels of leptin at baseline than those remaining nondiabetic (P<0.001). After adjustment for confounders, high leptin levels and high leptin/body mass index ratio were independently associated with incident diabetes over 11 years in men (odds ratio for top versus bottom quartile of leptin 2.18; 95% CI: 1.09-4.35), but not in women. CONCLUSION: We conclude that high leptin levels are associated with the future development of diabetes, and the association is independent of other factors in men, but not in women.

Dietary Westernisation: conceptualisation and measurement in Mauritius.

OBJECTIVES: The aims of the study were to provide information that will contribute to conceptualising what is called "dietary Westernisation", and to provide an example of measuring it on an individual level. DESIGN: Food consumption frequency and demographic data on adults in Mauritius were examined in 1988, 1992 and 1998. In 1992, a 24-hour recall was also included. The cross-sectional samples consisted of 1115 (age 25-74 years) Mauritians in 1987/88, 1917 (age 30-74 years) in 1992 and 2239 (age 20-74 years) in 1998. Principal components analysis was carried out on daily consumption frequencies of 10 indicator foods (white rice, white bakery bread, pulses, processed meat, poultry, fresh/frozen fish, butter, margarine, whole milk and skimmed/low-fat milk). Correlations between dietary patterns and selected food consumption frequencies were examined in each survey year. RESULTS: Four dietary patterns were identified as being related to dietary Westernisation. The Traditional dietary pattern was characterised by higher consumption frequencies of Indian breads, salted/smoked fish and sugar-sweetened tea. The Western dietary pattern was characterised by higher consumption frequencies of cakes/pastries, meat and many Western fast foods like burgers, but, surprisingly, also by brown bread, breakfast cereals and salad. The Bread/butter dietary pattern predominantly described more frequent consumption of bread compared with rice. The Margarine/milk dietary pattern was inconsistently related with staple foods. Younger, educated and wealthier Mauritians appeared to adopt Western dietary patterns earlier. CONCLUSIONS: This study suggests that relatively few indicator foods are needed for measuring dietary Westernisation. Dietary Westernisation in a non-Western country may also include shifts towards voluntary consumption of healthier foods.

Increasing prevalence of Type 2 diabetes mellitus in all ethnic groups in Mauritius.

AIMS: To describe the prevalence of different stages of glucose intolerance in a population from Mauritius followed over 11 years. METHODS: Population-based surveys were undertaken in the multiethnic nation of Mauritius in 1987, 1992 and 1998, with 5083, 6616, and 6291 participants, respectively. Questionnaires, anthropometric measurements, and a 2-h 75-g oral glucose tolerance test were included. Subjects aged between 25 and 75 years with classifiable data were identified; 4991, 6463 and 5392 from 1987, 1992 and 1998, respectively. Glucose tolerance was classified according to WHO 1999 criteria. RESULTS: The prevalence of Type 2 diabetes increased significantly during the period studied, from 12.8% in 1987, to 15.2% in 1992, and 17.9% in 1998. The increasing prevalence was seen in both men and women, and in all age groups. The prevalence of known diabetes (KDM) increased progressively, and more markedly than the increase in newly diagnosed diabetes (NDM). A diagnosis of impaired glucose tolerance (IGT) was more prevalent amongst women whereas impaired fasting glucose (IFG) was more common amongst men. The prevalences of IGT and IFG did not change markedly during the period. The prevalence of diabetes and IGT was similar for participants of Indian, Creole and Chinese background in each survey, and the increasing prevalence of diabetes was seen in all ethnic groups. CONCLUSION: In this study, we report an increasing prevalence of diabetes over an 11-year period in Mauritius. This increase was seen in both sexes, and in all age and ethnic groups, and was mainly due to an increase in the numbers of those with known diabetes.

High incidence of type 2 diabetes and increasing conversion rates from impaired fasting glucose and impaired glucose tolerance to diabetes in Mauritius.

OBJECTIVE: To describe the incidence of different stages of glucose intolerance in a population from Mauritius followed over 11 years. RESEARCH DESIGN, METHODS AND SUBJECTS: Population-based surveys were undertaken in the multi-ethnic nation of Mauritius in 1987, 1992 and 1998 with 5083, 6616 and 6291 participants, respectively. Questionnaires, anthropometric measurements, and a 2-h 75-g oral glucose tolerance test were included. Three cohorts aged between 25 and 79 years with classifiable glucose tolerance data were identified; 3680 between 1987 and 1992, 4178 between 1992 and 1998, and 2631 between 1987 and 1998. Glucose tolerance was classified according to WHO 1999 criteria. RESULTS: The incidence rate of type 2 diabetes was higher between 1992 and 1998 than between 1987 and 1992. In men, the incidence was similar between cohorts (24.5 and 25.4 per 1000 person-years) whereas the incidence increased in women (23.3 and 16.4 per 1000 person-years). The incidence of diabetes peaked in the 45-54 year age group and then plateaued or fell. The incidences of impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) decreased in both men and women. Of normoglycaemic subjects at baseline, more women than men developed IGT and more men than women developed IFG. Of those labelled as IFG in 1987, 38% developed diabetes after 11 years. The corresponding figure for IGT was 46%. CONCLUSIONS: In this study, we report changes in incidence rates of glucose intolerance over a 11-year period. In particular, differences between men and women were observed. The increased incidence of IGT in women compared with men, and increased incidence of IFG in men compared with women was consistent with, and explains the sex biases seen in the prevalences of these states.

Gender differences in the prevalence of impaired fasting glycaemia and impaired glucose tolerance in Mauritius. Does sex matter?

OBJECTIVE: To examine gender differences in the characteristics and prevalence of various categories of glucose tolerance in a population study in Mauritius. RESEARCH DESIGN AND METHODS: In 1998, a community-based cross-sectional survey was conducted in Mauritius. Categories of glucose metabolism were determined in 5388 adults, with an oral glucose tolerance test given to those who did not have previously diagnosed diabetes (n=4036). Other cardiovascular risk factors were assessed among those without known diabetes. RESULTS: For men and women the prevalence of diabetes (22.0 vs. 21.8%, respectively) and the prevalence of coexisting impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) (3.2 vs. 2.9%) were similar. However, men were twice as likely as women to have isolated IFG [5.1% (4.2-6.0) vs. 2.9% (2.3-3.5)], despite being younger, thinner and with lower plasma insulin but higher lipids. Conversely, the prevalence of isolated IGT was lower in men [9.0% (7.9-10.2) vs. 13.9% (12.6-15.1)]. Among non-diabetic individuals, fasting glucose was higher in men than women, whereas 2-h glucose was higher in women. In people without diabetes, women had significantly higher body mass index, beta cell function (HOMA-B), fasting and 2-h insulin than men and significantly lower waist-hip ratios, waist circumference, insulin sensitivity (HOMA-S) and triglycerides. CONCLUSION: In Mauritius, the distribution of impaired glucose metabolism differs by sex. The observation that IFG is more prevalent in men and IGT more prevalent in women raises important questions about their underlying aetiology and the ability of the current glucose thresholds to equally identify men and women at high-risk of developing diabetes. IFG should be seen as a complimentary category of abnormal glucose tolerance, rather than a replacement for IGT.

Association of physical activity and serum insulin concentrations in two populations at high risk for type 2 diabetes but differing by BMI.

OBJECTIVE: Physical activity and insulin sensitivity are related in epidemiological studies, but the consistency of this finding among populations that greatly differ in body size is uncertain. The present multiethnic epidemiological study examined whether physical activity was related to insulin concentrations in two populations at high risk for diabetes that greatly differ by location, ethnic group, and BMI. RESEARCH DESIGN AND METHODS: The study populations consisted of 2,321 nondiabetic Pima Indian men and women aged 15-59 years from Arizona and 2,716 nondiabetic men and women aged 35-54 years from Mauritius. Insulin sensitivity was estimated by mean insulin concentration (average of the fasting and postload insulin), and total (i.e., leisure and occupational) physical activity was assessed by questionnaire. RESULTS: Pima men and women who were more active had significantly (P < 0.05) lower mean insulin concentrations than those less active (BMI and age-adjusted means were 179 vs. 200 and 237 vs. 268 pmol/l). Similar findings were noted in Mauritian men and women (94 vs. 122 and 127 vs. 148 pmol/l). In both populations, activity remained significantly associated with mean insulin concentration controlled for age, BMI, waist-to-thigh or waist-to-hip ratio, and mean glucose concentrations. CONCLUSIONS: Physical activity was negatively associated with insulin concentrations both in the Pima Indians, who tend to be overweight, and in Mauritians, who are leaner. These findings suggest a beneficial role of activity on insulin sensitivity that is separate from any influence of activity on body composition.

Leptin and other components of the Metabolic Syndrome in Mauritius--a factor analysis.

OBJECTIVE: To use factor analysis to examine the putative role of leptin in the Metabolic Syndrome, and to define better the associations among observed variables and the identified factors. DESIGN: Factor analysis of cross-sectional data from a 1987 survey. SUBJECTS: Non-diabetic residents of Mauritius who participated in population-based surveys in 1987 and 1992 (1414 men and 1654 women). MEASUREMENTS: Fasting and 2 h plasma glucose and insulin following a 75 g oral glucose load; seated blood pressure; body mass index (BMI); waist-to-hip ratio (WHR); and fasting serum triglycerides, HDL-cholesterol, leptin and uric acid concentrations. RESULTS: Principal components factor analysis revealed three factors for men and women that explained between 54 and 55% of the observed variance of the 12 measured variables. General features of these factors were as follows: factor 1, WHR, BMI, leptin, fasting and 2 h insulin, triglycerides, and HDL-cholesterol; factor 2, systolic and diastolic blood pressure, uric acid (men only), and fasting glucose (women only); and factor 3, fasting and 2 h glucose and insulin. Only three variables loaded on more than one factor with a loading > or = 0.4 (fasting and 2 h insulin, fasting glucose in women only). Leptin loaded on one factor only in both men and women. CONCLUSIONS: Since multiple factors underlie the Metabolic Syndrome, and since no observed variable loads on all three factors, more than one mechanism might account for the observed clustering of risk characteristics. Leptin does not unite features of this syndrome due to its loading on one factor only. Uric acid is related to a different factor in men and women. The absence of gender differences in factor loadings argues for similar mechanisms for the Metabolic Syndrome in men and women in Mauritius. International Journal of Obesity (2001) 25, 126-131

Features of the metabolic syndrome predict higher risk of diabetes and impaired glucose tolerance: a prospective study in Mauritius.

OBJECTIVE: To assess the independent and joint effects of the components of the metabolic syndrome, including leptin, which is a recently proposed addition to this syndrome, in predicting the cumulative incidence of impaired glucose tolerance (IGT) and diabetes among individuals with normal glucose tolerance. RESEARCH DESIGN AND METHODS: This prospective study involved 2,605 residents of Mauritius with normal glucose tolerance who were followed for 5 years for IGT or diabetes onset in relation to total and regional adiposity (BMI, waist-to-hip ratio [WHR]), fasting and 2-h 75-g oral glucose load glucose and insulin, total and HDL cholesterol, blood pressure, serum uric acid, triglyceride, and leptin levels. RESULTS: A multivariate logistic regression model adjusted for age, sex, ethnicity, and diabetes family history showed a significantly higher linear increase in risk of IGT and diabetes in association with the following variables only: fasting glucose (odds ratio 1.89 [95% CI 1.51-2.34]), 2-h glucose (1.68 [1.50-1.88]), WHR (1.30 [1.10-1.52]), BMI (1.04 [1.00-1.08]), and serum uric acid (1.37 [1.20-1.57]). However, a nonlinear increase was seen with serum triglyceride and plasma leptin concentrations. No risk factors resulted in joint effects that were greater than expected from combining individual effects. CONCLUSIONS: Metabolic syndrome features independently predict a higher risk of diabetes or IGT in normoglycemic subjects but in combination confer no higher-than-expected risk of these outcomes. At higher concentrations of triglycerides and leptin, risk plateaus and even declines slightly.

Decreasing prevalence of cigarette smoking in the middle income country of Mauritius: questionnaire survey.

OBJECTIVES: To describe changes in the prevalence of cigarette smoking in the middle income country of Mauritius from 1987 to 1998, and to relate these changes to legislative and health promotion efforts over the same period. DESIGN: Questionnaire survey. SETTING: Mauritius, an island in the Indian Ocean with a population of about 1.2 million (about 70% south Asian, 2% Chinese, and 28% Creole). PARTICIPANTS: Data were obtained from 5072 participants in 1987, 6573 in 1992, and 6281 in 1998. MAIN OUTCOME MEASURES: Prevalence of current smoking in 1987, 1992, and 1998, sales of cigarettes in Mauritius, and information on activities for control of tobacco. RESULTS: Self reported cigarette smoking has been decreasing in Mauritius since 1987, with the largest decrease between 1987 and 1992. From 1987 to 1998 smoking prevalence decreased by 23% in men and 61% in women. Smoking decreased across all age and ethnic groups and across different levels of income and education. Sales of cigarettes also decreased in line with smoking prevalence. CONCLUSIONS: The introduction of cigarette taxes, a limited health promotion programme, and the absence of massive promotional campaigns by the sole tobacco company on Mauritius have led to a striking and continued decrease in smoking prevalence and cigarette consumption on the island.

Impaired fasting glucose: how low should it go?

OBJECTIVE: Impaired fasting glucose (IFG) has been recently introduced as a stage of abnormal carbohydrate metabolism, but the evidence on which its glucose limits (fasting plasma glucose [FPG] 6.1-6.9 mmol/l) are based is not strong. The aim of this study was to determine if 6.1 mmol/l represents a clear cutoff in terms of the risk of future diabetes and in terms of elevated cardiovascular risk factor levels, and to examine the use of other lower limits of IFG. RESEARCH DESIGN AND METHODS: A population-based survey of the island of Mauritius was undertaken in 1987, with a follow-up survey 5 years later. On both occasions, an oral glucose tolerance test was performed and cardiovascular risk factors were measured. RESULTS: Data were available from 4,721 nondiabetic people at baseline, and from 3,542 at follow-up. At baseline, blood pressure, lipids, and obesity increased in a linear fashion with increasing FPG, with no evidence of a threshold effect. The risk of developing hypertension at follow-up was greater for those people with baseline FPG > or =6.1 mmol/l (P<0.001). The risk of developing diabetes at follow-up increased with increasing baseline FPG, but there was little evidence of a threshold near 6.1 mmol/l. CONCLUSIONS: Cardiovascular risk and risk of future diabetes increase continually with increasing FPG, and there is no threshold value on which to base a definition of IFG. If a lower limit of approximately 5.8 mmol/l is used, the category defines a group more similar to the group with impaired glucose tolerance, with regard to total prevalence and the risk of subsequent diabetes.

Isolated post-challenge hyperglycaemia confirmed as a risk factor for mortality.

AIMS/HYPOTHESIS: The aim of this study was to examine the possible link between isolated post-challenge hyperglycaemia (2-h post-challenge plasma glucose >/= 11.1 mmol/l, and fasting plasma glucose < 7.0 mmol/l) and mortality. METHODS: The data from three population based longitudinal studies (in Mauritius, Fiji and Nauru) were pooled and mortality rates were determined in 9179 people who were followed for between 5 and 12 years. RESULTS: There were 595 people with previously diagnosed diabetes, and 799 with newly diagnosed diabetes, of whom 243 (31) had isolated post-challenge hyperglycaemia. In comparison with people without diabetes, people with isolated post-challenge hyperglycaemia had an increased risk of all-cause mortality [Cox proportional hazards ratio (95 % CI): 2.7 (1.8-3.9) - men; 2.0 (1.3-3.3) - women], and of cardiovascular mortality [2.3 (1.2-4.2) - men; 2.6 (1.3-5.1) - women]. In addition, men with isolated post-challenge hyperglycaemia had a high risk of cancer death [8.0 (3.6-17.9)]. CONCLUSION/INTERPRETATION: These data show that isolated post-challenge hyperglycaemia, which can only be identified by the 2-h glucose, is common, and at least doubles the mortality risk. This should be considered in the design of screening programmes that use only fasting glucose.

Impaired fasting glucose or impaired glucose tolerance. What best predicts future diabetes in Mauritius?

OBJECTIVE: To determine if impaired fasting glucose (IFG; fasting plasma glucose level 6.1-6.9 mmol/l) can predict future type 2 diabetes as accurately as does impaired glucose tolerance (IGT; 2-h plasma glucose level 7.8-11.0 mmol/l). RESEARCH DESIGN AND METHODS: A longitudinal population-based study was performed with surveys in 1987 and 1992 on the island of Mauritius, assessing diabetes status by the oral glucose tolerance test. A total of 3,717 subjects took part in both surveys. Of these subjects, 3,229 were not diabetic in 1987 and formed the basis of this study. RESULTS: At baseline, there were 607 subjects with IGT and 266 subjects with IFG. There were 297 subjects who developed diabetes by 1992. For predicting progression to type 2 diabetes, the sensitivity, specificity, and positive predictive values were 26, 94, and 29% for IFG and 50, 84, and 24% for IGT, respectively. Only 26% of subjects that progressed to type 2 diabetes were predicted by their IFG values, but a further 35% could be identified by also considering IGT. The sensitivities were 24% for IFG and 37% for IGT in men and 26% for IFG and 66% for IGT in women, respectively. CONCLUSIONS: These data demonstrate the higher sensitivity of IGT over IFG for predicting progression to type 2 diabetes. Screening by the criteria for IFG alone would identify fewer people who subsequently progress to type 2 diabetes than would the oral glucose tolerance test.

Do leptin levels predict weight gain?--A 5-year follow-up study in Mauritius. Mauritius Non-communicable Disease Study Group.

OBJECTIVE: To investigate whether relative baseline leptin levels predict long-term changes in adiposity and/or its distribution. RESEARCH METHODS AND PROCEDURES: In a longitudinal study of 2888 nondiabetic Mauritians aged 25 years to 74 years who participated in population-based surveys in 1987 and 1992, changes in body mass index (BMI), waist/hip ratio (WHR), and waist circumference were compared between "hyperleptinemic," "normoleptinemic," and "hypoleptinemic" groups. "Relative leptin levels" were calculated as standardized residuals from the regression of log10 leptin on baseline BMI to provide a leptin measure independent of BMI. Analyses were performed within each sex. A linear regression model was used to assess the effect of standardized residuals on changes in BMI, WHR, and waist circumference, independent of baseline BMI, age, fasting insulin, and ethnicity. RESULTS: After adjusting for age and baseline BMI by analysis of covariance, there was no difference in changes in BMI, WHR, or waist circumference between men with low, normal, or high relative leptin levels. Among women, there was a significant difference in deltaWHR across leptin groups, such that the largest increase occurred in the "normal" leptin group. For both men and women, the linear regression models explained approximately 10% of variation in dependent variables, and the only significant independent variables were age, BMI, and being of Chinese origin, compared with Indian origin. DISCUSSION: These findings do not support a role for leptin concentration in predicting weight gain or changes in fat distribution in adults over a 5-year period.

Is there a relationship between leptin and insulin sensitivity independent of obesity? A population-based study in the Indian Ocean nation of Mauritius. Mauritius NCD Study Group.

OBJECTIVE: It has been shown previously in smaller studies that fasting serum leptin and insulin concentrations are highly correlated, and insulin sensitive men have lower leptin levels than insulin resistant men matched for fat mass. We have examined the association between insulin resistance (assessed by fasting insulin) and leptin after controlling for overall and central adiposity in a population-based cohort. DESIGN: Leptin levels were compared across insulin resistance quartiles within three categories of obesity (tertiles of body mass index (BMI)). Partial correlation coefficents and multiple linear regression models were used to assess the relationship between leptin and fasting insulin after adjusting for BMI and waist to hip ratio (WHR) or waist circumference. SUBJECTS: Subjects were normoglycemic participants of a 1987 non-communicable diseases survey conducted in the multiethnic population of Mauritius. 1227 men and 1310 women of Asian Indian, Creole and Chinese ethnicity had normal glucose tolerance and fasting serum leptin measurements. RESULTS: Mean serum leptin concentration increased across quartiles of fasting insulin in each BMI group and gender, after controlling for BMI, WHR and age. Furthermore, fasting insulin was a significant determinant of serum leptin concentration, independent of BMI and WHR, in both men and women. Similar results were found if waist circumference replaced BMI and WHR in the model. CONCLUSION: These results suggest that insulin resistance/concentration may contribute to the relatively wide variation in leptin levels seen at similar levels of body mass or alternatively, leptin may play a role in the etiology of insulin resistance. Further studies will be important to determine whether the hyperleptinemia/insulin resistance relationship has a role in the natural history of obesity, Type 2 diabetes mellitus and the other metabolic abnormalities associated with insulin resistance.

Physical inactivity and glucose intolerance in the multiethnic island of Mauritius.

The island nation of Mauritius, located in the southwest Indian Ocean, has a high prevalence of non-insulin-dependent diabetes mellitus (NIDDM) among all of its ethnic groups (Hindu and Muslim Indians, African-origin Creoles, and Chinese). These high rates of NIDDM among groups of varying genetic background provide strong support for the importance of environmental components in the etiology of the disease. Research in Mauritius using a simple activity scale has suggested that physical inactivity may be one of these components. The current investigation further examined the association between glucose tolerance and physical activity in middle-aged nondiabetic residents of Mauritius using a more extensive physical activity questionnaire (the Modifiable Activity Questionnaire). Excluding individuals with NIDDM, a statistically significant (P < 0.05) inverse relationship between physical activity and 2-h post-load glucose concentration was found for both males (rho = -0.14) and females (rho = -0.11). Stratifying by ethnic group, similar inverse correlations were observed in Hindu, Creole, and Chinese males, and in Hindu females (P < 0.05), as well as weaker relationships in Muslim males and Creole females (P < 0.10). Total physical activity remained an independent predictor of 2-h post-load glucose concentration after controlling for body mass index, waist-hip ratio, age, and family history of NIDDM. These data are supportive of a potentially important role of physical activity in the prevention of NIDDM in middle-aged inhabitants of Mauritius.

Changes in population cholesterol concentrations and other cardiovascular risk factor levels after five years of the non-communicable disease intervention programme in Mauritius. Mauritius Non-communicable Disease Study Group.

OBJECTIVE: To study changes in the prevalence of risk factors for cardiovascular disease after a five year population-wide intervention programme promoting a healthy lifestyle in a developing country. DESIGN: Cross sectional cluster surveys in 1987 and 1992. Methodology included a two hour 75 g oral glucose tolerance test, measurement of body mass index, waist:hip ratio, basal lipid concentrations, and blood pressure; and a lifestyle questionnaire. SETTING: Mauritius, in the Indian Ocean. SUBJECTS: All adults aged 25-74 years residing in geographically defined clusters. MAIN OUTCOME MEASURES: Age standardised prevalence of categorical disease and risk factor conditions and mean levels and frequency distributions of continuous variables. RESULTS: Response rates were 86.2% (5080/5892) in 1987 and 89.5% (5162/5770) in 1992. Significant decreases were found in the prevalence of hypertension (15.0% to 12.1% in men and 12.4% to 10.9% in women); cigarette smoking (58.2% to 47.2% and 6.9% to 3.7% respectively); and heavy alcohol consumption (38.2% to 14.4% and 2.6% to 0.6% respectively). Moderate leisure physical activity increased from 16.9% to 22.1% in men and from 1.3% to 2.7% in women. Mean population serum total cholesterol concentration fell appreciably from 5.5 mmol/l to 4.7 mmol/l (P < 0.001). The prevalence of overweight or obesity increased, and the rates of glucose intolerance changed little. The population frequency distributions of blood pressure, serum lipid concentration, and a composite risk factor score shifted advantageously. CONCLUSIONS: Lifestyle intervention projects can be implemented and have positive effects in developing countries. A pronounced improvement in the population lipid profile in Mauritius was probably related to a change in the saturated fat content of a widely used cooking oil.

Is hyperinsulinaemia a central characteristic of a chronic cardiovascular risk factor clustering syndrome? Mixed findings in Asian Indian, Creole and Chinese Mauritians. Mauritius Noncommunicable Disease Study Group.

The aim of the study was to investigate whether the constellation of cardiovascular disease risk factors, described as Insulin Resistance Syndrome, exists in the multi-ethnic population of Mauritius, and to assess whether hyperinsulinaemia is the key feature of this syndrome. A sample of 5080 Mauritian subjects (aged 25-74 years) was examined in a noncommunicable diseases survey in 1987. Survey procedure included an oral glucose tolerance test, and anthropometric, blood pressure, plasma lipids and serum insulin measurements. Abnormal glucose tolerance (diabetes and impaired glucose tolerance), general obesity, upper-body obesity, hypertension, low HDL-cholesterol, and hypertriglyceridaemia were defined as risk factor conditions. Mean values for a series of risk factor variables were compared between reference subjects (no risk factors) and those with a risk factor condition (either one condition only, or in combination with one or more others). Prevalence estimates for each risk factor condition in combination with three or more other conditions were three to four times greater than expected by chance, and levels of risk factors for subjects with more than one risk factor condition were further away from the reference levels than for those with just one condition. Fasting and 2-h serum insulin levels were elevated for each condition when in combination with others, or to a lesser extent when isolated. However, this was not the case for isolated hypertension where insulin levels were not elevated. When adjusted for age, sex, and body mass index, insulin levels were only significantly elevated in subjects with upper-body obesity if in association with general obesity.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin and blood pressure levels are not independently related in Mauritians of Asian Indian, Creole or Chinese origin. The Mauritius Non-communicable Disease Study Group.

OBJECTIVES: There is conflicting evidence of a link between circulating insulin concentrations and blood pressure. The aim of this study, therefore, was to investigate this relationship in a representative population sample of different ethnic groups. DESIGN: A cross-sectional study was performed, using a random cluster sample of 5080 adults aged 25-74 years from the Indian Ocean island of Mauritius. METHODS: Glucose tolerance was assessed with a 75-g oral glucose tolerance test. Hypertension and glucose tolerance were classified using World Health Organization criteria. Subjects known to have diabetes before the survey were excluded from these analyses, leaving 3104 Asian Indian, 1256 African-origin Creole and 384 Chinese subjects eligible for this study. RESULTS: There were statistically significant linear correlations between fasting and 2-h insulin and mean blood pressure in all sex-ethnic subgroups, except for Chinese men. However, after controlling for age and the body mass index, partial correlations were much reduced and remained significant only for fasting insulin in Indian men (r = 0.07, P < 0.01) and women (r = 0.09, P < 0.001) and 2-h insulin in Chinese women (r = 0.15, P < 0.05). After controlling for age and body mass index, mean fasting and 2-h insulin concentrations were not significantly different between hypertensive and normotensive subjects in any of 36 possible subgroups defined by ethnic group, gender or glucose tolerance (normal, impaired glucose tolerance or newly diagnosed diabetes). In both men and women with normal glucose tolerance (ethnic groups combined) there was no evidence of increasing systolic or diastolic blood pressure across quartiles of either fasting or 2-h serum insulin within any quartile of the body mass index. By contrast, at any given level of serum insulin there was a clear association between an increasing body mass index and increasing blood pressure, suggesting strongly that insulin is not the final pathway by which obesity influences blood pressure. CONCLUSIONS: This study of three ethnic groups does not support the hypothesis that the circulating insulin concentration is an independent determinant of blood pressure in populations.