The prevalence of diabetes mellitus in a traditional-living Polynesian population: the Wallis Island survey

A Hypothesis: Moderate Consumption of Alcohol Contributes to Lower Prevalence of Type 2 Diabetes Due to the Scavenging of Alpha-Dicarbonyls by Dietary Polyphenols

The world is experiencing an epidemic of type-2-diabetes mellitus (T2DM). This has led to increased morbidity and mortality, explosive growth in health care budgets, and an even greater adverse, if indirect, impact on societies and economies of affected countries. While genetic susceptibility to T2DM is a major determinant of its prevalence, changes in lifestyles also play a role. One such change has been a transition from traditional diets characterized by low caloric and high nutrient density to calorie-rich but nutrient-poor Western diets. Given this, one solution to the epidemic of T2DM would be to abandon Western diets and revert to traditional eating patterns. However, traditional diets cannot provide enough calories for the increasing global population, so transition from traditional to Western foodstuffs appears to be irreversible. Consequently, the only practical solution to problems caused by these changes is to modify Western diets, possibly by supplementing them with functional foods containing nutrients that would compensate for these dietary deficits. I present in this study a hypothesis to explain why shifts from traditional to Western diets have been so problematic and to suggest nutrients that may counteract these adverse effects. I postulate that the components of traditional diets that may compensate for deficiencies of Westerns diets are scavengers of reactive α-dicarbonyls produced as unavoidable by-products of glucose and lipid metabolism. Most important among these scavengers are some plant secondary metabolites: polyphenols, phlorotannins, and carotenoids. They are found in alcoholic beverages and are abundant in seasonings, cocoa, coffee, tea, whole grains, pigmented vegetables, fruits, and berries.

Overweight and obesity in New Caledonian adults: Results from measured and adjusted self-reported anthropometric data

AIMS

To estimate the overweight (OW) and obesity (Ob) prevalence and associated socio-demographic risk factors in New Caledonian adults aged 18-67years.

METHODS

From a randomly selected cross-sectional population survey, self-reported (n=2513) and measured (n=736) height and weight data were collected. Separate linear regression analyses for measured weight and height were performed, using cases with both self-reported weight and height and socio-demographic variables. The final weight and height assigned to each case was either measured or predicted from the regression (n=2075). OW prevalence was defined as: Body Mass Index (BMI) ≥25 and <30kg/m^-2; and Ob: BMI ≥30kg/m^-2. Samples were weighted to the general adult population. Prevalence and Odds ratios (ORs) were calculated by gender, and adjusted for socio-demographic variables, to assess differentials in OW, Ob and OW-Ob, using multinomial and logistic regressions.

RESULTS

Male (M) OW was 35% (95% CI: 31-38), Ob 29% (95% CI: 26-32) and OW-Ob 64% (95% CI: 60-67); female (F) OW was 26% (95% CI: 23-28), Ob 34% (95% CI: 31-37) and OW-Ob 60% (95% CI: 57-63). Compared to Melanesians (OR=1.0) for male/female: Polynesians had the highest prevalence of OW (1.7/1.5), Ob (4.7/3.5), and OW-Ob (3.0/2.5); New Caledonian-born Europeans had greater OW, Ob and OW-Ob (0.3/0.4) than immigrant Europeans (0.2/0.2).

CONCLUSIONS

Findings contribute to obesity comparisons with other Pacific Islands, and they establish trends in New Caledonia for targeting policies and strategies of prevention.

Glucose homeostasis can be differentially modulated by varying individual components of a western diet

Chronic overconsumption of a Western diet has been identified as a major risk factor for diabetes, yet precisely how each individual component contributes to defects in glucose homeostasis independent of consumption of other macronutrients remains unclear. Eight-week-old male Sprague Dawley rats were randomized to feeding with one of six semi-pure diets: control, processed (high advanced glycation end products/AGE), high protein, high dextrose (glucose polymer), high in saturated fat (plant origin), or high in saturated fat (animal origin). After chronic feeding for 24 weeks, body composition was determined by bioelectrical impedance spectroscopy and glucose homeostasis was assessed. When compared to the control and high AGE diets, excess consumption of the diet high in saturated fat (animal source) increased body weight and adiposity, and decreased insulin sensitivity, as defined by HOMA IR, impaired skeletal muscle insulin signaling and insulin hypersecretion in the context of increased circulating glucagon-like peptide (GLP-1). Compared to the control diet, chronic consumption of the high AGE, protein or dextrose diet increased fasting plasma glucose, decreased fasting plasma insulin and insulin secretion. These diets also reduced circulating GLP-1 concentrations. These data suggest that individual components of a western diet have differential effects in modulating glucose homeostasis and adiposity. These data provide clear evidence of a link between over-consumption of a western diet and the development of diabetes.

Type 2 diabetes and impaired glucose tolerance in aboriginal populations: a global perspective

OBJECTIVE

To perform a systematic review of the prevalence of type 2 diabetes and impaired glucose tolerance (IGT) in aboriginal populations worldwide.

RESEARCH DESIGN AND METHODS

A Medline search from 1966 to 2005 was conducted. Studies were selected if they utilized accepted diagnostic criteria for type 2 diabetes. Year of study, sample size, response rate, age range, and prevalence of type 2 diabetes and IGT were documented.

RESULTS

Forty-two studies were selected, comprising 59 populations. Although the majority demonstrated a several-fold elevation of type 2 diabetes prevalence as compared to non-aboriginal populations, this was not a universal finding; a small number of populations studied actually had a low prevalence of type 2 diabetes and IGT. Lower prevalences were found in rural compared with urban populations. Interestingly, we were also able to document an inverse relationship between the ratio of IGT/type 2 diabetes and type 2 diabetes prevalence. These data are consistent with the hypothesis that those populations with the very highest rates of type 2 diabetes appear to have progressed past the prediabetes stages in the natural history of this metabolic disorder.

CONCLUSIONS

Type 2 diabetes and IGT prevalence rates vary widely amongst the world's aboriginal populations. Despite very different histories and cultures, the consequences of rapid changes in nutrition and exercise appear to have very similar metabolic consequences on aboriginal populations, the magnitude of which may be determined by the strength of the genetic susceptibility.

Glucose tolerance and ancestral genetic admixture in six semitraditional pacific populations

Population-based data on 1,842 subjects from six semitraditional Pacific communities, collected in the years 1978-1983, have been compared in order to examine the hypotheses that differences in the distribution of plasma glucose concentration between populations are to some extent genetically determined, and that non-Austronesian (NAN) Melanesians are relatively resistant to glucose intolerance. Semitraditional communities were chosen for study so that the comparison would be minimally confounded by either known or as yet undetermined environmental factors associated with nontraditional living, the effects of which may vary between populations. The samples were also selected so as to provide a gradient of proportional NAN and AN admixture. They were drawn from the following regions: the highlands of Papua New Guinea, New Caledonia, Fiji, the Wallis Islands, Western Samoa, and Kiribati (formerly the Gilbert Islands). The Papua New Guinea highlanders, of entirely NAN ancestry, were regarded as the baseline population. A gradient of increasing mean 2-hr plasma glucose concentration was observed across the six populations and differences persisted between populations, after controlling for age and obesity. Variations in diet, physical activity, and degree of sociocultural modernization were not considered a sufficient or consistent explanation of these findings and they therefore lend tentative support to the hypothesis of a genetic component to variability in glucose tolerance. The relationship between population estimates of glucose tolerance and estimates of the genetic distance from the baseline NAN Melanesian sample was examined. With the notable exception of Fiji, there was evidence of a linear correlation between the two parameters.

Prevention of type 2 diabetes in young people: a theoretical perspective

Type 2 diabetes in youth is an increasing public health concern, especially in certain minority populations. The current paper consists of four sections. First, we establish the significance of the problem by presenting an overview of epidemiological and physiological evidence. Second, we discuss behavioral issues relevant to the prevention of type 2 diabetes in youth. Third, a qualitative review of existing prevention interventions specific to type 2 diabetes in youth is presented. Results suggest that modest improvements in social cognitive, dietary, and exercise outcomes are possible with diabetes intervention studies, although beneficial changes are difficult to sustain over the long term. Although theoretical frameworks are not always explicit, most studies have utilized elements of the social cognitive theory. Less attention has been paid to sociocultural and community organization variables. Finally, the paper discusses issues of risk definition and intervention sustainability, and presents a comprehensive, theoretically diverse model for the prevention of type 2 diabetes in youth. In summary, we suggest that theories of the natural history and pathophysiology of type 2 diabetes are important to identify modifiable risk factors, while theories of behavioral change are essential to modify the risk factors identified. The combination of sound physiological and behavioral theories should form the basis of prevention intervention design. In addition, an ecologic approach that takes into consideration the dynamic interactions of personal, social, and environmental factors would best promote the long-term adoption of healthful behaviors in a supportive, meaningful, and personally enjoyable context.

A case-control study of physical activity and non-insulin dependent diabetes mellitus (NIDDM). the San Luis Valley Diabetes Study

PURPOSE

The purpose of this study was to examine the association between physical activity and non-insulin dependent diabetes mellitus (NIDDM).

METHODS

We conducted a population-based case-control study in Hispanic and non-Hispanic white men and women, ages 20-74. A total of 167 cases with NIDDM and 1100 controls with normal glucose tolerance were included. All subjects completed an oral glucose tolerance test.

RESULTS

Persons with recently diagnosed NIDDM reported significantly lower levels of physical activity than control subjects. For total metabolic units, the odds ratio for subjects in the highest tertile compared to those in the lowest tertile was 0.60 (95% confidence interval (CI) = 0.37-0.98) after adjusting for age, sex, ethnicity, and family history of diabetes. The adjusted odds ratio for persons reporting high levels of vigorous activity (at least three times per week for 20 minutes) was also less than 1, but was not statistically significant (odds ratio (OR) = 0.73, 95% CI = 0.47-1.14). Similar adjusted odds ratios were observed for high versus low levels of self-assessed work activity (OR = 0.50, 95% CI = 0.34-0.74) and leisure time physical activity (OR = 0.62, 95% CI = 0.44-0.90). Further adjustments for body mass index attenuated the strength of the association between physical activity and NIDDM. This is consistent with the hypothesis that obesity is one consequence of physical inactivity that puts individuals at increased risk for NIDDM. The association of physical activity and NIDDM was stronger in Hispanic than in non-Hispanic white subjects, although this difference was not statistically significant.

CONCLUSIONS

High levels of physical activity are associated with lower odds of NIDDM and this relationship may be stronger in Hispanic subjects.

American College of Sports Medicine position stand. Exercise and type 2 diabetes

Physical activity, including appropriate endurance and resistance training, is a major therapeutic modality for type 2 diabetes. Unfortunately, too often physical activity is an underutilized therapy. Favorable changes in glucose tolerance and insulin sensitivity usually deteriorate within 72 h of the last exercise session: consequently, regular physical activity is imperative to sustain glucose-lowering effects and improved insulin sensitivity. Individuals with type 2 diabetes should strive to achieve a minimum cumulative total of 1,000 kcal x wk(-1) from physical activities. Those with type 2 diabetes generally have a lower level of fitness (VO2max) than nondiabetic individuals. and therefore exercise intensity should be at a comfortable level (RPE 10-12) in the initial periods of training and should progress cautiously as tolerance for activity improves. Resistance training has the potential to improve muscle strength and endurance, enhance flexibility and body composition, decrease risk factors for cardiovascular disease, and result in improved glucose tolerance and insulin sensitivity. Modifications to exercise type and/or intensity may be necessary for those who have complications of diabetes. Individuals with type 2 diabetes may develop autonomic neuropathy, which affects the heart rate response to exercise, and as a result, ratings of perceived exertion rather than heart rate may need to be used for moderating intensity of physical activity. Although walking may be the most convenient low-impact mode, some persons, because of peripheral neuropathy and/or foot problems, may need to do non-weight-bearing activities. Outcome expectations may contribute significantly to motivation to begin and maintain an exercise program. Interventions designed to encourage adoption of an exercise regimen must be responsive to the individual's current stage of readiness and focus efforts on moving the individual through the various "stages of change."

Low-intensity endurance exercise training, plasma lipoproteins and the risk of coronary heart disease

Physically active individuals generally show a reduced risk of coronary heart disease (CHD) compared to the sedentary population. However, whether such reduction in CHD risk mainly results from the concomitant improvement in cardiorespiratory fitness or from the alterations in CHD risk factors has yet to be clearly established. Furthermore, there is still some controversy regarding the potential associations between endurance training-induced changes in metabolic variables considered as CHD risk factors (plasma glucose, insulin and lipoprotein levels) and the magnitude of improvement in cardiorespiratory fitness. From the results of several studies discussed in this article, it is proposed that prolonged endurance exercise of low intensity (approximately 50% VO2max), performed on an almost daily basis, seems to significantly improve metabolic variables considered as CHD risk factors through mechanisms that are likely to be independent from the training-related changes in cardiorespiratory fitness. The notion of 'metabolic fitness' is introduced and can be defined as the state of a ste of metabolic variables relevant to CHD risk and affected by the level of physical activity. Evidence available suggests that these metabolic variables are not closely related to the adaptation of cardiorespiratory fitness in response to exercise training. The concept of metabolic fitness has several implications for the prescription of exercise and for the primary and secondary prevention of CHD. Indeed, emphasis should not be placed on aiming at increasing VO2max through high-intensity exercise, but rather on producing a substantial increase in daily energy expenditure that will eventually lead to weight loss and related improvements in carbohydrate and lipid metabolism. Therefore, from a practical standpoint, although a 1 h daily walk may not have marked effects on cardiorespiratory fitness, it probably represents an exercise prescription that is likely to substantially improve 'metabolic fitness', thereby reducing the risk of CHD.

Cardiovascular risk factor levels in ethnic Hawaiians

We report a cardiovascular risk factor survey of "native" Hawaiians 20-59 years old (70 percent, or 257), living on the Hawaiian Homestead lands on the island of Molokai, Hawaii. More than 60 percent of both sexes were overweight. Among males, 42 percent were smokers. The percent of the population with systolic blood pressure greater than 140 mm Hg or a diastolic pressure greater than 90 mm Hg or taking hypertensive medications was 14 percent of those ages 20-39 and 36 percent of those ages 40-59. The percent with serum cholesterol greater than or equal to 6.2 mmol/L ranged from 8 percent of those 20-29 years old to 46 percent in those 50-59 years old. Two percent of those ages 20-29 had a history of diabetes, or 2 + or greater glycosuria by dipstick, as did 23 percent of those ages 50-59. The majority of the known diabetics exhibited glycosuria and elevated glycohemoglobin levels, indicating poor control. Hypertension, although usually known to the participant, was frequently uncontrolled. From these data, it appears that among this group of Hawaiians major risk factors for cardiovascular disease were frequent, while at the same time the levels of awareness and/or control for most of these factors were low.

Determining diabetes prevalence: a rational basis for the use of fasting plasma glucose concentrations?

The World Health Organization and the National Diabetes Data Group each recommend a diagnostic cut-off point for diabetes of 7.8 mmol l-1 for fasting plasma glucose concentrations as part of the diagnostic criteria for epidemiological studies. However, this cut-off has been shown to be insensitive compared with a screening test based on 2-h plasma glucose levels. In thirteen Pacific populations, from four ethnic groups (Asian Indian, Melanesian, Micronesian, and Polynesian), we have examined whether a different cut-off point for fasting plasma glucose would be more accurate for obtaining an estimate of the prevalence of diabetes when compared with 2-h levels. A fasting plasma glucose diagnostic cut-off of 7.0 mmol l-1 gave an estimate of prevalence not significantly different from that based on the 2-h plasma glucose in 12 of the 13 populations (mean difference 0.27, range -1.51 to +2.44,%). On the other hand, when a cut-off of 7.8 mmol l-1 for fasting plasma glucose was used, the resulting prevalence over-estimated the 2-h glucose prevalence in all populations (mean difference 1.91, range 0.14-5.80,%). Thus for Pacific populations, a fasting plasma glucose cut-off of 7.0 mmol l-1 provides estimates of prevalence that are equivalent to those based on 2-h plasma glucose levels. In epidemiological studies designed to estimate diabetes prevalence, we recommend use of a fasting plasma glucose cut-off of 7.0 mmol l-1 in preference to a detection level of 7.8 mmol l-1, if glucose loading is not possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of abnormal glucose tolerance in six Solomon Islands populations

A survey of blood glucose levels in six Solomon Islands populations may support the hypothesis that susceptibility to diabetes is almost absent among non-Austronesian-speaking Melanesians regardless of their level of modernization. Among Austronesian-speaking Melanesians, however, diabetes is emerging. Differences in prevalence rates of diabetes between Austronesians and non-Austronesian speakers in this survey are significant (P less than .0001).

Glucose tolerance in Polynesia: association with obesity and island of residence

Data on five Polynesian populations, obtained by standardized population surveys conducted during the years 1978-1980, were examined for associations between glucose tolerance and both obesity and island of residence. In both sexes, after allowing for the influence of age and obesity, there was a significant difference in glucose tolerance between the three populations considered, subjectively, to be the less traditional and the two considered as retaining a more traditional lifestyle. Regression models predicting diabetic status were weaker than those using glucose tolerance as the dependent variable, probably due to the small number of diabetic subjects in the samples. As all subjects were of Polynesian ancestry, and the results could not be explained by knowledge of ancestral affiliations between the five populations, environmental, rather than genetic factors may have been the determinants of the observed differences in glucose tolerance. This finding highlights the need for a more sophisticated approach to the study of the association between socio-cultural modernization and chronic disease in the Pacific.

Glucose tolerance in Polynesia. Population-based surveys in Rarotonga and Niue

Glucose tolerance and the prevalence of impaired glucose tolerance (IGT) and diabetes in the Polynesian populations of Rarotonga and Niue were studied in 1980. Both Rarotongans and Niueans have been considerably influenced by sociocultural modernization and (in the case of Rarotonga) tourism. In both populations, the prevalence of abnormal glucose tolerance exceeded 10% in men and 15% in women. There was an association between glucose tolerance and age and obesity in both sexes, but not between glucose tolerance and physical activity. Glucose tolerance did not differ between Rarotongans and Niueans after allowing for differences in age and obesity. Comparisons between normal subjects, those with impaired glucose tolerance (IGT) and diabetic subjects with respect to factors that are traditionally associated with glucose intolerance provided some support for IGT as a truly intermediate diagnostic category of glucose tolerance.

Diabetes in Wallis Polynesians: a comparison of residents of Wallis Island and first generation migrants to Noumea, New Caledonia

A comparative study of diabetes, impaired glucose tolerance and obesity was undertaken in samples of rural Wallisians of Wallis Island and first generation Wallisian migrants in the urban centre of Noumea, New Caledonia. Approximately 20-25% of the adult population of the 2 communities was included in the study. Wallisians in Noumea tended to be more obese than those in Wallis (particularly females). The prevalence of diabetes was 7 and 4 times higher in Noumea compared to Wallis for males and females respectively. Differences in the extent of obesity appeared to account for some of the difference in prevalence of diabetes, but other environmental factors (such as constituents of the diet, and exercise) must be operative as well. The results of this study are consistent with previous findings concerning environmental determinants of diabetes in Pacific populations.

Physical activity and prevalence of diabetes in Melanesian and Indian men in Fiji

In Fiji Melanesian and Indian men, prevalence of diabetes is more than twice as high in those graded as sedentary or undertaking light activity as in those classed as performing moderate or heavy exercise. This difference was present in both ethnic groups, and maintained when age, obesity, and urban/rural- status were taken into account. It is concluded that, in the population under study, there is epidemiological evidence for the role of physical inactivity as an independent risk factor for Type 2 (non-insulin-dependent) diabetes.