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

High-Intensity Interval Training Reversed High-Fat Diet-Induced M1-Macrophage Polarization in Rat Adipose Tissue via Inhibition of NOTCH Signaling

Introduction

There is accumulating evidence on the beneficial effect of exercise intervention in the management of metabolic disorders; however, the molecular mechanism is still unclear. Here, the current study aimed to compare the effect of high-intensity interval training (HIIT) and continuous endurance training (CET) on serum and adipose-tissue markers of M1/M2 macrophage polarization.

Methods

A total of 45 healthy male Wistar rats were divided into groups of normal chow (n=10) and high-fat diet (HFD) (n=35). Then, rats receiving the HFD were randomly divided into four groups. Training programs were performed for 5 days/week over 10 weeks. The CET protocol included 30 minutes running at 50%–60% of VO_2max. The HIIT protocol consisted of five repeated intervals of 2-minute sprints on the treadmill at 80%–90% VO_2max workload with 1 minute's 30%–35% VO_2max interval for each rat. Then, biochemical parameters were assessed. Macrophage-polarization markers were assessed at mRNA and protein levels by real-time PCR and Western blotting, respectively.

Results

Both exercise-training programs, especially HIIT, reversed increased serum biochemical parameters (glucose, triglycerides, cholesterol, Homeostatic Model Assessment of Insulin Resistance, and hsCRP), M1-polarization markers (circulating IL6, TNFα, and adipose-tissue mRNA expression of IL6, TNFα and iNOS), M2 markers (CD206, CD163, and IL10 expression), as well as pIκKB, pNFκB, and NICD expression in HFD-induced diabetes.

Conclusion

Our findings suggest that despite devoting less time, the HIIT workout is a more effective intervention for diabetes management. Moreover, HIIT reverses HFD-induced macrophage polarization by targeting the NFκB and NOTCH signaling pathways.

Associated risk factors and their interactions with type 2 diabetes among the elderly with prediabetes in rural areas of Yiyang City: A nested case-control study

To explore associated risk factors and their interactions with type 2 diabetes (T2DM) among the elderly with prediabetes in rural areas in China.A nested case-control study was conducted in a fixed cohort to identify the risk factors for T2DM among the elderly with prediabetes in rural areas of Yiyang City in China. A total of 37 elderly with T2DM were included in the cases group and 111 elderly subjects with prediabetes were matched in the control group. Data related to sociodemographic characteristics, lifestyle behavior, and anthropometric variables were collected by trained staff using standard tools. The risk factors for T2DM were determined using conditional logistic regression analysis, and their additive interactions were also explored.Multivariable conditional logistic regression analysis results showed that overweight/obesity (odds ratio [OR] = 4.80, 95% confidence interval [CI]: 1.20-12.28), family history of diabetes (OR = 3.63, 95% CI: 1.03-12.81), physically inactive (OR = 3.08, 95% CI: 1.14-8.30), high waist-to-hip ratio (WHR) (OR = 3.15, 95% CI: 1.27-7.80), and inadequate diabetes-specific health literacy (DSHL) (OR = 3.92, 95% CI: 1.14-13.48) increased the risk for T2DM. Additive interactions for T2DM were observed between a family history of diabetes and high WHR with a relative excess risk of interaction (RERI) of 10.02 (95% CI: 4.25, 15.78), and between high WHR and overweight or obesity, with an RERI of 3.90 (95% CI: 0.36, 7.44).The independent risk factors for T2DM are overweight or obesity, high WHR, family history of diabetes, physically inactive, and inadequate DSHL. High WHR as a risk factor for T2DM has additive interactions with family history of diabetes and overweight or obesity.

Physical activity is associated with lower insulin and C-peptide during glucose challenge in children and adolescents with family background of diabetes

AIMS

Children and adolescents with a family history of diabetes are at increased risk of overweight, but little is known about the potentially beneficial effects of physical activity on these children. The objective of this study was to investigate the association between moderate to vigorous physical activity (MVPA) and metabolic and inflammatory risks in children and adolescents with a family background of Type 1 diabetes or gestational diabetes.

METHODS

Valid MVPA measurements, made with accelerometers, were available from 234 participants (median age, 10.2 years) who had a first-degree relative with either Type 1 or gestational diabetes. Anthropometric and metabolic measurements were made and cytokines measured, and were correlated with MVPA measurements, with stepwise adjustment for confounding factors, in a cross-sectional analysis.

RESULTS

MVPA was negatively associated with insulin and C-peptide during challenge with an oral glucose tolerance test. MVPA was also significantly positively associated with the insulin sensitivity index, whereas no consistently significant associations were found between MVPA and BMI, blood pressure or cytokine levels.

DISCUSSION

Our findings indicate that physical activity may have beneficial effects on insulin and C-peptide metabolism in children and adolescents with a family background of diabetes, but show no evidence of a protective association with other health-related outcomes.

Physical Activity Patterns and Risk of Type 2 Diabetes and Metabolic Syndrome in Middle-Aged and Elderly Northern Chinese Adults

The main aim of this study is to quantitatively describe the status of physical activity and evaluate its levels in a rural population and to investigate the association between the quantifiable physical activity and type 2 diabetes and metabolic syndrome. In total, 2076 participants aged over 40 years were included in a cross-sectional analysis. Physical activity status and the contributions of different types of activity were evaluated. The association between social behaviors and physical activities was analyzed. In addition, the impact of physical activities on type 2 diabetes mellitus and metabolic syndrome was also analyzed by logistic regression. Approximately half of the total activity in rural areas consisted of work-related activity (49.3%) followed by commuting (30.2%) and recreational activity (20.5%). In rural areas, the prevalence of physical activity levels was 28.6% for low levels, 47.3% for moderate levels, and 24.1% for high levels. Educational level showed a significant negative association with the physical activity level. Lower physical activity shows a strong and significant association with type 2 diabetes and metabolic syndrome. In conclusion, insufficient physical activity among rural people over 40 years old increases the risk of type 2 diabetes and metabolic syndrome. Population-wide and individualized guidelines for physical activities especially recreational physical activities should be developed.

Environmentally Driven Increases in Type 2 Diabetes and Obesity in Pima Indians and Non-Pimas in Mexico Over a 15-Year Period: The Maycoba Project

OBJECTIVE

The global epidemics of type 2 diabetes and obesity have been attributed to the interaction between lifestyle changes and genetic predisposition to these diseases. We compared the prevalences of type 2 diabetes and obesity in Mexican Pima Indians, presumed to have a high genetic predisposition to these diseases, to those in their non-Pima neighbors, both of whom over a 15-year period experienced a transition from a traditional to a more modern lifestyle.

RESEARCH DESIGN AND METHODS

Prevalence of diabetes, impaired fasting glucose, impaired glucose tolerance, and obesity in Mexican Pimas (n = 359) and non-Pima Mexicans (n = 251) were determined in 2010 using methods identical to those used in 1995.

RESULTS

During this 15-year period, age-adjusted diabetes prevalence was unchanged in Pima men (5.8% in 1995 vs. 6.1% in 2010) yet increased in non-Pima men from 0.0 to 8.6% (P < 0.05). Diabetes prevalence tended to increase in both Pima women (9.4 vs. 13.4%) and non-Pima women (4.8 vs. 9.5%). Age-adjusted prevalence of obesity increased significantly in all groups (6.6 vs. 15.7% in Pima men; 8.5 vs. 20.5% in non-Pima men; 18.9. vs 36.3% in Pima women; 29.5 vs. 42.9% in non-Pima women).

CONCLUSIONS

Type 2 diabetes prevalence increased between 1995 and 2010 in non-Pima men, and to a lesser degree in women of both groups, but it did not increase in Pima men. Prevalence of obesity increased among Pimas and non-Pimas of both sexes. These changes occurred concomitantly with an environmental transition from a traditional to a more modernized lifestyle.

Psychological wellbeing and biochemical modulation in response to weight loss in obese type 2 diabetes patients

BACKGROUND

Obesity in type 2 diabetes patients is a serious health issue by itself; it is also associated with other health problems including psychiatric illnesses. The psychological effects of dieting and weight loss have been a matter of controversy in the field of obesity management.

OBJECTIVE

The aim of this study was to compare the impact of weight loss because of aerobic exercise training and dietary measures on psychological wellbeing and biochemical modulation in obese type 2 diabetes patients.

MATERIAL AND METHODS

One hundred obese type 2 diabetes patients of both sexes participated in this study, and were included into two equal groups. The first group (A) received aerobic exercise training, three sessions per week for three months combined with dietary measures. The second group (B) received no training intervention for three months.

RESULTS

There was a significant decrease in body mass index (BMI), leptin, total cholesterol (TC), low density lipoprotein cholesterol (LDL-c), triglycerides(TG), homeostasis model assessment-insulin resistance- index (HOMA-IR) , beck depression inventory (BDI ) & profile of mood states(POMS) and increase in high density lipoprotein cholesterol (HDL-c) & Rosenberg self-esteem scale (RSES) of group (A) after treatments, but the changes of group (B) were not significant. Moreover, there were significant differences between mean levels of the investigated parameters of group (B) and group (A) at the end of the study.

CONCLUSION

Physical training and dietary measures can be used as methods of choice for psychological wellbeing and biochemical modulation in obese type 2 diabetes patients.

Comparison of two indices of diet quality with acculturation factors and demographics in Haitian Americans

This study examined associations of language preference and length of stay in the United States and diet among 132 Haitian Americans aged ≥35, born in Haiti. Two dietary indices, Healthy Eating Index (HEI) and Alternative Healthy Eating Index (AHEI), were used to assess dietary quality. Years in the United States (>15 years; B = 0.063, p = .012) and female gender (B = 5.63, p = .028) were positively associated with AHEI. Lower HEI scores were associated with speaking no English (B = -6.11, p = .026). Participants reporting an income under 20,000/yr had lower AHEI scores (B = -7.63, p = .014). Concurrent use of these indices would provide a screening tool for nutrition intervention. Public health programs targeting low-cost resources, such as community gardening, are recommended to reduce health disparities among this population.

Physical activity energy expenditure is associated with 2-h insulin independently of obesity among Inuit in Greenland

AIMS

Indigenous populations throughout the Arctic are experiencing a rapid increase in the prevalence of obesity and type 2 diabetes. The role of physical activity in relation to glucose metabolism in Arctic populations is not well studied. We examined the association between objectively measured physical activity energy expenditure (PAEE) and glucose metabolism in a population-based study of adult Inuit in Greenland.

METHODS

Cross-sectional data were collected by combined accelerometry and heart rate monitoring (ACC+HR) among Inuit (18+ years) in Greenland during 2005-2010 (n=1545). PAEE was calculated and the associations with fasting glucose, 2-h glucose, fasting insulin, 2-h insulin concentrations and body composition were analysed by linear regression.

RESULTS

An inverse association between PAEE and fasting insulin, 2-h insulin, 2-h glucose, fat percentage, BMI and waist circumference (WC) was found after adjustments by age and sex. Only the association between PAEE and 2-h insulin remained significant after adjustment by WC (P=0.01), most pronounced at low levels of PAEE indicating a threshold around 35-40kJ/kg/day. No overall linear trend was found for fasting glucose and 2-h glucose.

CONCLUSIONS

This population-based study showed that PAEE was associated with 2-h insulin independently of obesity in an inverse dose-response relation. Insufficient physical activity may contribute to impaired glucose tolerance through a pathway including alterations in obesity and fat distribution. Both obesity and low levels of PAEE may be important contributing risk factors for the increasing prevalence of type 2 diabetes mellitus among Inuit in Greenland, but additional risk factors should be examined in this indigenous population.

Metabolic syndrome and insulin resistance: underlying causes and modification by exercise training

Metabolic syndrome (MS) is a collection of cardiometabolic risk factors that includes obesity, insulin resistance, hypertension, and dyslipidemia. Although there has been significant debate regarding the criteria and concept of the syndrome, this clustering of risk factors is unequivocally linked to an increased risk of developing type 2 diabetes and cardiovascular disease. Regardless of the true definition, based on current population estimates, nearly 100 million have MS. It is often characterized by insulin resistance, which some have suggested is a major underpinning link between physical inactivity and MS. The purpose of this review is to: (i) provide an overview of the history, causes and clinical aspects of MS, (ii) review the molecular mechanisms of insulin action and the causes of insulin resistance, and (iii) discuss the epidemiological and intervention data on the effects of exercise on MS and insulin sensitivity.

Increased risk of type 2 diabetes with ascending social class in urban South Indians is explained by obesity: The Chennai urban rural epidemiology study (CURES-116)

AIM

The aim of this study is to determine the factors responsible for differences in the prevalence of diabetes mellitus (DM) in subjects of different social class in an urban South Indian population.

MATERIALS AND METHODS

Analyses were based on the cross-sectional data from the Chennai Urban Rural Epidemiology Study of 1989 individuals, aged ≥20 years. Entered in the analyses were information obtained by self-report on (1) household income; (2) family history of diabetes; (3) physical activity; (4) smoking status; (5) alcohol consumption. Biochemical, clinical and anthropometrical measurements were performed and included in the analyses. Social class was classified based on income as low (Rs. <2000) intermediate (Rs. 2000-5000`) and high (Rs. 5000-20000).

RESULTS

The prevalence rates of DM were 12.0%, 18.4% and 21.7% in low, intermediate and high social class, respectively (P < 0.001). A significant increase in the risk of diabetes was found with ascending social class (Intermediate class: Odds ratio [OR], 1.7 [confidence interval [CI], 1.2-2.3]; High class: OR, 2.0 [CI-1.4-2.9]). The multivariable adjusted logistic regression analysis revealed that the effect of social class on the risk of diabetes remained significant (P = 0.016) when age, family history of diabetes and blood pressure were included. However, with the inclusion of abdominal obesity in the model, the significant effect of social class disappeared (P = 0.087).

CONCLUSION

An increased prevalence of DM was found in the higher social class in this urban South Indian population, which is explained by obesity.

Deficits in physical function among young childhood cancer survivors

PURPOSE

Childhood cancer survivors (CCSs) are at risk for physical disability. The aim of this investigation was to characterize and compare physical performance among CCSs and a group of siblings age < 18 years and determine if diagnosis, treatment, and physical activity levels were associated with lower performance scores.

METHODS

CCSs ≥ 5 years from diagnosis and a sibling comparison group were recruited and evaluated for strength, mobility, and fitness. Physical performance measures were compared in regression models between survivors and siblings by diagnosis and among survivors by treatment exposures and physical activity levels.

RESULTS

CCSs (n = 183; mean age ± standard deviation [SD], 13.5 ± 2.5 years; 53% male) scored lower than siblings (n = 147; mean age ± SD, 13.4 ± 2.4 years; 50% male) on lower-extremity strength testing, the timed up-and-go (TUG) test, and the 6-minute walk (6MW) test, despite reporting similar levels and types of habitual physical activity. The lowest scores were prevalent among survivors of CNS tumors and bone and soft tissue sarcomas on strength testing (score ± SD: CNS tumors, 76.5 ± 4.7; sarcoma 67.1 ± 7.2 v siblings, 87.3 ± 2.4 Newton-meters quadricep strength at 90° per second; P = .04 and .01, respectively) and among CNS tumor survivors on the TUG (score ± SD: 5.1 ± 0.1 v siblings, 4.4 ± 0.1 seconds; P < .001) and 6MW tests (score ± SD: 533.3 ± 15.6 v siblings, 594.1 ± 8.3 m; P < .001).

CONCLUSION

CCSs may have underlying physiologic deficits that interfere with function that cannot be completely overcome by participation in regular physical activity. These survivors may need referral for specialized exercise interventions in addition to usual counseling to remain physically active.

Physical activity is related to insulin sensitivity in children and adolescents, independent of adiposity: a review of the literature

In adults, there is evidence that physical activity effectively improves insulin sensitivity regardless of adiposity. Whether this is also the case in children and adolescents is less clear. Clarifying this matter may help to identify the best outcomes to target in exercise programs for these age groups, where changes in adiposity may not always be desirable or realistic. A review of the literature was conducted on studies that examined the relationships of physical activity, cardiorespiratory fitness and strength with insulin sensitivity independent of adiposity in children and adolescents. Experimental (intervention) and correlational (longitudinal and cross-sectional) studies on participants ages 18 years and younger were identified. A total of 42 studies were included in this review. Sample sizes in the studies ranged from 14 to 4955 participants, with individual ages ranging from 5 to 19 years. A significant relationship with insulin sensitivity existed in 78% of studies on physical activity, 69% of studies on cardiorespiratory fitness and 66% of studies on strength. In studies that examined both physical activity and cardiorespiratory fitness concurrently, evidence suggests that they are both correlated with insulin sensitivity independent of adiposity, especially when physical activity is at higher intensities. However, the strength of this relationship might be influenced by study design, measurement techniques and participant characteristics. This is the first review of its type to take research design into account and to examine study outcomes according to participant ethnicity, gender, age, pubertal status and weight status.

Leisure time and occupational physical activity in relation to obesity and insulin resistance: a population-based study from the Skaraborg Project in Sweden

The objective was to study obesity and insulin resistance in relation to leisure time physical activity (LTPA) and occupational physical activity (OPA) in a Swedish population, with particular focus on sex differences. Using a cross-sectional design, waist circumference, body mass index (BMI), glucose/insulin metabolism, blood pressure, heart rate, self-reported education, smoking, alcohol consumption, LTPA, and OPA were assessed in 1745 men and women (30-74 years) randomly chosen from 2 municipalities in southwestern Sweden. In both men and women, LTPA was inversely associated with BMI, waist circumference, and the homeostasis model assessment of insulin resistance (HOMA-IR), respectively. These associations remained statistically significant after adjustments for age, OPA, education, alcohol consumption, smoking, and study area, and also for BMI in the analyses concerning waist circumference and HOMA-IR. A statistically significant interaction term (P = .030), adjusted for multiple confounders, revealed a stronger association between LTPA and HOMA-IR in women compared with men. Occupational physical activity was positively associated with BMI (P < .001), waist circumference (P < .001), and HOMA-IR (P = .001), however, only in women. These associations remained when adjusting for multiple confounders. The sex differences were confirmed by statistically significant interaction terms between sex and OPA in association with BMI, waist circumference, and HOMA-IR, respectively. The observed sex differences regarding the strength of the association between LTPA and insulin resistance, and the positive association between OPA and obesity and insulin resistance found solely in women, warrant further investigation. Although exploration of the metabolic effects of OPA appears to be needed, thorough measurement of potential confounders is also vital to understand contextual effects.

Metabolic profile in two physically active Inuit groups consuming either a western or a traditional Inuit diet

Objectives

To evaluate the effect of regular physical activity on metabolic risk factors and blood pressure in Inuit with high BMI consuming a western diet (high amount of saturated fatty acids and carbohydrates with a high glycemic index).

Study design

Cross sectional study, comparing Inuit eating a western diet with Inuit eating a traditional diet.

Methods

Two physically active Greenland Inuit groups consuming different diet, 20 eating a traditional diet (Qaanaaq) and 15 eating a western diet (TAB), age (mean (range)); 38, (22–58) yrs, BMI; 28 (20–40) were subjected to an oral glucose tolerance test (OGTT), blood sampling, maximal oxygen uptake test, food interview/collection and monitoring of physical activity.

Results

All Inuit had a normal OGTT. Fasting glucose (mmol/l), HbA1c (%), total cholesterol (mmol/l) and HDL-C (mmol/l) were for Qaanaaq women: 4.8±0.2, 5.3±0.1, 4.96±0.42, 1.34±0.06, for Qaanaaq men: 4.9±0.1, 5.7±0.1, 5.08±0.31, 1.28±0.09, for TAB women: 5.1±0.2, 5.3±0.1, 6.22±0.39, 1.86±0.13, for TAB men: 5.1±0.2, 5.3±0.1, 6.23±0.15, 1.60±0.10. No differences were found in systolic or diastolic blood pressure between the groups. There was a more adverse distribution of small dense LDL-C particles and higher total cholesterol and HDL-C concentration in the western diet group.

Conclusions

Diabetes or impaired glucose tolerance was not found in the Inuit consuming either the western or the traditional diet, and this could, at least partly, be due to the high amount of regular daily physical activity. However, when considering the total cardio vascular risk profile the Inuit consuming a western diet had a less healthy profile than the Inuit consuming a traditional diet.

The Healthy Eating Index and the Alternate Healthy Eating Index as predictors of 10-year CHD risk in Cuban Americans with and without type 2 diabetes. Public Health Nutr. 2011;14:2006-2014. [PMID: 21729463 DOI: 10.1017/s1368980011001054]

OBJECTIVE

To examine the relationship between dietary patterns, as measured by the Healthy Eating Index (HEI) and the Alternate Healthy Eating Index (AHEI), and 10-year predicted CHD risk in Cuban Americans with and without type 2 diabetes (T2D).

DESIGN

In a cross-sectional study participants were selected from two randomly generated mailing lists of individuals with and without T2D. HEI and AHEI scores were calculated from a self-reported FFQ. CHD risk was determined using the 10-year CHD risk calculator of the Adult Treatment Panel III.

SETTING

Miami Dade and Broward Counties, FL, USA.

SUBJECTS

Cuban Americans (n 358) aged ≥30 years.

RESULTS

Participants with T2D had a higher waist circumference (P = 0·001) and 10-year CHD risk score (P = 0·008) compared with those without T2D. Participants without T2D had a higher energy intake (P = 0·034), total blood cholesterol (P = 0·007), HDL cholesterol (P = 0·001) and HEI score (P = 0·006) compared with participants with T2D. AHEI score was a significant predictor of 10-year CHD risk (F(1,351) = 4·44, P = 0·036). An association between AHEI and 10-year CHD risk was found only for participants with T2D (β = -0·244, se = 0·049, P = 0·001).ConclusionThe present study showed that only participants with T2D with significantly higher AHEI scores had lower scores for 10-year predicted CHD risk. No association was found between HEI score and CHD risk among Cuban Americans. Individuals with T2D are advised to follow the AHEI dietary pattern.

Dietary glycemic index and load in relation to cardiovascular disease risk factors in Cuban American population

OBJECTIVE

To examine whether dietary glycemic index (GI) or glycemic load (GL) had an effect on the cardiovascular disease (CVD) risk factors and whether the effects were dependent on the diabetes status in the Cuban American population.

DESIGN

A case–control, single-time-point study.

METHODS

A total of 324 middle-aged Cuban American adults had completed data on fasting blood lipids, physical activity level and usual dietary intake using a validated food frequency questionnaire. Published GI values were assigned to food items and average dietary GI and GL were calculated per participant.

RESULTS

Subjects without type 2 diabetes (T2D) were 3.3 times more likely to be in the recommended, highest high-density lipoprotein-cholesterol category if they were in the second dietary GL tertile as compared with those in the first dietary GL tertile (P = 0.042, 95% confidence interval = 1.94, 10.78).

CONCLUSIONS

The results of the present study suggest that in this sample of Cuban Americans a high GI or GL diet do not adversely affects blood lipids, especially among subjects without T2D.

Differences in insulin resistance in Mexican and U.S. Pima Indians with normal glucose tolerance

CONTEXT

Insulin resistance is a major risk factor for the development of type 2 diabetes in Pima Indians, a population with the highest prevalence of type 2 diabetes mellitus in the world. Their Mexican counterpart, living a traditional lifestyle in the mountains of Sonora, have at least 5 times less diabetes than the U.S. Pima Indians.

OBJECTIVE

We evaluated whether Mexican Pima Indians had lower insulin resistance than U.S. Pima Indians.

DESIGN AND PATIENTS

We compared fasting insulin and homeostasis model assessment for insulin resistance (HOMA-IR) in 194 Mexican Pima Indians (100 females, 94 males) and 449 U.S. Pima Indians (246 females, 203 males) with normal glucose tolerance from a cross-sectional study. Adjusted differences of log-transformed outcomes (fasting insulin and HOMA-IR) between groups were evaluated using multiple linear regression models and paired t test in a matched subset.

RESULTS

Unadjusted fasting insulin and HOMA-IR were much lower in the Mexican Pima Indians than in their U.S. counterparts. After adjusting by obesity, age, and sex, mean (95% confidence interval) for fasting insulin was 6.22 (5.34-7.24) vs. 13.56 μU/ml (12.27-14.97) and for HOMA-IR 1.40 (1.20-1.64) vs. 3.07 (2.77-3.40), respectively, for Mexican Pima and U.S. Pima Indians. Results were confirmed in subset matched for age, sex, and body fat.

CONCLUSION

Our results indicate that Mexican Pima Indians have lower insulin resistance in comparison with their genetically related U.S. counterparts, even after controlling for differences in obesity, age, and sex. This finding underscores the importance of lifestyle factors as protecting factors against insulin resistance in individuals with a high propensity to develop diabetes.

Effect of physical activity and obesity on type 2 diabetes in a middle-aged population

BACKGROUND

The physical activity has been associated with a reduced risk of type 2 diabetes. The aim of this study was to examine the effect of physical activities such as occupational, household and daily lifestyle activities and obesity on the prevalence of type 2 diabetes in middle-aged population.

METHODS

All people (n = 2053), aged 45-64 years were selected for this study from the large sample of population-based cross-sectional data collected in the 1990-1994 by National Health Survey of Pakistan. The participants completed in-person interviews at baseline; the overall response rate was 92.6%. The Cox proportional hazards model was used to estimate the risk of developing the type 2 diabetes.

RESULTS

Stair climbing was found to be inversely associated with the risk of diabetes and cycling was also associated with a reduced risk of type 2 diabetes (RR = 0.82; 95% CI 0.68-1.00, P = .048). The relationship between physical activity and reduced risk of diabetes adjusted for age and body mass index was statistically significant only in women (P < .01).

CONCLUSIONS

This study provides an incentive that physical activity in leisure-time exercise or daily activity reduces the risk of type 2 diabetes in a high-risk population.

Genetic influences on type 2 diabetes and metabolic syndrome related quantitative traits in Mauritius

Epidemiological studies report a high prevalence of type 2 diabetes and metabolic syndrome in the island nation of Mauritius. The Mauritius Family Study was initiated to examine heritable factors that contribute to these high rates of prevalence and consists of 400 individuals in 24 large extended multigenerational pedigrees. Anthropometric and biochemical measurements relating to the metabolic syndrome were undertaken in addition to family and lifestyle based information for each individual. Variance components methods were used to determine the heritability of the type 2 diabetes and metabolic syndrome related quantitative traits. The cohort was made up of 218 females (55%) and 182 males with 22% diagnosed with type 2 diabetes and a further 30% having impaired glucose tolerance or impaired fasting glucose. Notably BMI was not significantly increased in those with type 2 diabetes (P= .12), however a significant increase in waist circumference was observed in these groups (P= .02). The heritable proportion of trait variance was substantial and greater than values previously published for hip circumference, LDL and total cholesterol, diastolic and systolic blood pressure and serum creatinine. Height, weight and BMI heritabilities were all in the upper range of those previously reported. The phenotypic characteristics of the Mauritius family cohort are similar to those previously reported in the Mauritian population with a high observed prevalence rate of type 2 diabetes. A high heritability for key type 2 diabetes and metabolic syndrome related phenotypes (range 0.23 to 0.68), suggest the cohort will have utility in identifying genes that influence these quantitative traits.

Self-reported low physical function is associated with diabetes mellitus and insulin resistance in HIV-positive and HIV-negative men

AIM

To investigate the association between self-reported physical function (as a surrogate for physical activity) and diabetes mellitus (DM) and insulin resistance (IR) among HIV-positive and -negative men.

METHOD

A total of 384 HIV-negative and 274 HIV-positive men from the Pitt Men's Study contributed data. DM was defined by fasting serum glucose levels. IR was calculated using the homeostasis model assessment. The Physical Functioning 10 Scale from the Short Form-36 Health Survey measured physical function. Multivariate logistic regression assessed the independent association between physical function and DM and IR.

RESULTS

Physical function, older age and Black race were associated with DM in multivariate analyses. Physical function/HIV interaction, older age, higher body mass index, HIV infection and Black race were associated with IR in multivariate analyses.

CONCLUSION

Self-reported low physical function is associated with DM and IR in HIV-negative and -positive men.

Does home-based exercise improve body mass index in patients with type 2 diabetes? Results of a feasibility trial

AIMS

This feasibility trial evaluated the use, safety, and short-term benefits of a home-based exercise intervention designed to increase physical activity among adults with diabetes.

METHODS

Participants with type 2 diabetes in a group practice were recruited and randomly assigned to the home-based exercise intervention or usual care. Participants were given diabetes self-management education, instructed to exercise 30 min 5 days/week, and were followed for 3 months. The intervention contained three exercise routines (aerobic and resistance exercises). Outcomes included changes from baseline at 3 months between groups in body mass index (BMI), quality of life, A1C, and blood pressure.

RESULTS

Seventy-six sedentary adults completed the study: 49% intervention group, 68% women, 47% black, mean age 56.6+/-9.6 years. Using intention to treat analysis, a trend towards improvement between groups for BMI (mean change -0.4 versus 0.1, respectively; P=0.06) was identified. Thirty-eight percent of the intervention group adhered to 80% of the exercise recommendation and significantly improved BMI (-1.07; P<0.05). No other differences were detected between groups.

CONCLUSIONS

Home-based exercise interventions have potential to reduce BMI in patients with diabetes. The results provide variance estimates necessary to power a larger study of longer duration.

Orlistat in the prevention of diabetes in the obese patient

There has been an increase in the concern about preventing type 2 diabetes mellitus (T2DM), a disease with great and increasing prevalence. The prevalence of obesity, physical inactivity, Western processed diet, important risk factors for the development of T2DM, are also rising. Free fatty acids are increased in obesity and reduce insulin clearance and increase hepatic glucose production. Implementation of a healthy lifestyle has been show to slow the progression of impaired glucose tolerance to T2DM. Orlistat is an inhibitor of lipase activity, with proved efficacy in body weight reduction and long-term management of obesity and more favorable effects on carbohydrate metabolism and it was prospectively shown in XENDOS study that orlistat promoted long-term weight loss and prevented T2DM onset in obese individuals with normal and impaired glucose tolerance at baseline over four years. This benefit could be associated to the weight loss itself, to the limited absorption of lipids and reduction of plasma free fatty acids, to increased production of incretins or to modulation of secretion of cytokines by adipocytes, all effects secondary to orlistat treatment. A proposed strategy is to identify subjects at highest risk to receive a drug intervention, using lifestyle interventions alone at the community level.

Low physical activity and obesity: causes of chronic disease or simply predictors?

BACKGROUND AND PURPOSE

Many studies have shown associations between risk of morbidity and mortality with both obesity and low physical activity (PA), but association does not imply causality. Moreover, there is an inverse relationship between PA and obesity; therefore, controlling for one of these factors when investigating the risk associated with the other is essential. The purpose of this review is to determine whether low PA and obesity actually cause metabolic dysfunction and chronic disease, especially type 2 diabetes (T2D), rather than simply operating as predictors or markers.

METHODS

The case for causality is strengthened if the following two conditions are satisfied: first, that significant associations between obesity or low PA and risk persist after controlling appropriately; and second, that the physiological mechanisms by which obesity or low PA may exert a causal effect are clearly established. The studies examined include those that have used cardiorespiratory (CR) fitness as a surrogate measure for PA, thus also providing evidence for low CR fitness as an independent risk factor in its own right.

RESULTS AND CONCLUSIONS

Low PA and poor CR fitness are independent predictors of mortality related to type 2 diabetes and chronic disease in general. Together with well-demonstrated mechanisms, there is strong evidence that low PA and low CR fitness are direct, independent causes of metabolic dysfunction and type 2 diabetes. Despite some reports to the contrary, there is evidence that both general and visceral obesity are predictors of mortality and morbidity after controlling for PA. However, in the absence of established mechanisms, evidence is insufficient to conclude that either general or visceral obesity is a direct, independent cause of metabolic dysfunction or type 2 diabetes.

The importance of free fatty acids in the development of Type 2 diabetes

The recent increase in the prevalence of obesity has been associated with a coincident rise in the prevalence of Type 2 diabetes, whereas weight loss has been shown to decrease the risk of Type 2 diabetes. The pathophysiological mechanisms that have been proposed to explain this link are fundamentally concerned with insulin resistance and the decline in pancreatic B-cell function that accompanies an increase in visceral obesity. They involve the rise in the plasma concentrations of free fatty acids (FFAs) that are associated with an increase in fat mass. Elevated levels of FFAs can lead to insulin resistance, and evidence is growing that B-cell function is impaired through lipotoxicity. Factors such as tumour necrosis factor-alpha (TNF-alpha) and adiponectin, released from adipose tissue, can also modulate insulin resistance. Many interventions that are helpful in treating or preventing Type 2 diabetes, such as weight loss and certain pharmacological interventions, reduce circulating FFA concentrations to a greater or lesser extent. Recent study results suggest that peroxisome proliferator-activated receptor (PPAR)gamma agonists have an effect on the development of Type 2 diabetes. However, in light of concerns over the apparent increase in congestive heart failure with PPARgamma agonists, their place in the prevention of Type 2 diabetes remains to be determined.

An update on the etiology and epidemiology of diabetes mellitus

Diabetes mellitus is one of the most common endocrine disorders affecting almost 6% of the world's population. The number of diabetic patients will reach 300 million in 2025 (International Diabetes Federation, 2001). More than 97% of these patients will have type II diabetes. The projected increase in the number of diabetic patients will strain the capabilities of healthcare providers the world over. Thus it is of paramount importance to revisit the causes and epidemiology of diabetes mellitus. Diabetes mellitus is caused by both environmental and genetic factors. The environmental factors that may lead to the development of diabetes mellitus include physical inactivity, drugs and toxic agents, obesity, viral infection, and location. While type I diabetes is not a genetically predestined disease, an increased susceptibility can be inherited. Genetic susceptibility plays a crucial role in the etiology and manifestation of type II diabetes, with concordance in monozygotic twins approaching 100%. Genetic factors may have to be modified by environmental factors for diabetes mellitus to become overt. An individual with a susceptible gene may become diabetic if environmental factors modify the expression of these genes. Since there is an increase in the trend at which diabetes prevail, it is evident that environmental factors are playing a more increasing role in the cause of diabetes mellitus. The incidence of type I diabetes ranged from 1.9 to 7.0/100,000/yr in Africa, 0.13 to 10/100,000/yr in Asia, approximately 4.4/100,000/yr in Australasia, 3.4 to 36/100,000/yr in Europe, 2.62 to 20.18/100,000/yr in the Middle East, 7.61 to 25.7/100,000/yr in North America, and 1.27 to 18/100,000/yr in South America. The epidemiology of type II diabetes is equally bleak. The prevalence of type II diabetes ranged from 0.3 to 17.9% in Africa, 1.2 to 14.6% in Asia, 0.7 to 11.6% in Europe, 4.6 to 40% in the Middle East, 6.69 to 28.2% in North America, and 2.01 to 17.4% in South America.

Daytime sleepiness, exercise, and physical function in older adults

The purpose of this study was to describe the association between sleepiness, exercise, and physical function in older adults, testing the hypothesis that sleepiness predicts decreased exercise and impaired physical function in this population. We performed a secondary analysis of data from the National Sleep Foundation's Sleep in America Poll, comparing frequency of exercise and ability to perform functional tasks between sleepy and non-sleepy subjects. Trained interviewers administered a scripted telephone survey. Participants (n = 1506) were community-dwelling older Americans (55-84 years) randomly chosen from geographically representative households with listed telephone numbers. Sleepiness 'so severe that it interferes with daytime activity' was dichotomized as 'daily/frequently' or 'never/rare'. Exercise frequency was scored 1-4 ('less than once a week' to 'more than five times a week'). Responses to five questions (walk 0.5 mile, climb stairs, push/pull heavy object, stoop/crouch/or kneel, write, handle small objects), rated 1-5 ('no difficulty' to 'unable to do'), were summed; a mean score of > or = 2.5 was considered impaired physical function. Daytime sleepiness predicted low exercise frequency while controlling for age and body mass index (BMI) (OR = 1.40, 95% CI 1.031-1.897, P = 0.031). Frequent daytime sleepiness predicted impaired physical function (OR = 2.76, 95%CI = 0.237-0.553, P = 0.001) after controlling for age, BMI, income and number of co-morbid conditions. The conclusion was that daytime sleepiness in older adults is associated with physical functional impairments and decreased exercise frequency. The findings suggest that sleepiness in older adults is not benign but has implications for continued physical decline and warrants attention.

Beneficial associations of physical activity with 2-h but not fasting blood glucose in Australian adults: the AusDiab study

OBJECTIVE

We examined the associations of physical activity with fasting plasma glucose (FPG) and with 2-h postload plasma glucose (2-h PG) in men and women with low, moderate, and high waist circumference.

RESEARCH DESIGN AND METHODS

The Australian Diabetes, Obesity and Lifestyle (AusDiab) study provided data on a population-based cross-sectional sample of 4,108 men and 5,106 women aged >or=25 years without known diabetes or health conditions that could affect physical activity. FPG and 2-h PG were obtained from an oral glucose tolerance test. Self-reported physical activity level was defined according to the current public health guidelines as active (>or=150 min/week across five or more sessions) or inactive (<150 min/week and/or less than five sessions). Sex-specific quintiles of physical activity time were used to ascertain dose response.

RESULTS

Being physically active and total physical activity time were independently and negatively associated with 2-h PG. When physical activity level was considered within each waist circumference category, 2-h PG was significantly lower in active high-waist circumference women (beta -0.30 [95% CI -0.59 to -0.01], P = 0.044) and active low-waist circumference men (beta -0.25 [-0.49 to -0.02], P = 0.036) compared with their inactive counterparts. Considered across physical activity and waist circumference categories, 2-h PG levels were not significantly different between active moderate-waist circumference participants and active low-waist circumference participants. Associations between physical activity and FPG were nonsignificant.

CONCLUSIONS

There are important differences between 2-h PG and FPG related to physical activity. It appears that 2-h PG is more sensitive to the beneficial effects of physical activity, and these benefits occur across the waist circumference spectrum.

Integrating conventional science and aboriginal perspectives on diabetes using fuzzy cognitive maps

There is concern among Aboriginal communities in Canada that conventional approaches to the treatment of diabetes are ineffective in part because they fail to recognize the local Aboriginal perspective on the causal determinants of diabetes. While this shortcoming has been recognized, there have been no explicit attempts to practically define these perspectives and prescribe how conventional health management might be altered to incorporate them. In part, this may be due to difficulties in communicating Aboriginal perspectives in a manner which permits incorporation into conventional science-based frameworks. Here we use fuzzy cognitive mapping (FCM) as a technique to represent and compare Canadian Aboriginal and conventional science perspectives on the determinants of diabetes as contained in published articles drawn from a search of Medline and PubMed (1966-2005). The FCM allows for a detailed description of the complex system of culture, spirituality and balance at the root of the Aboriginal view. It also highlights how, for these less tangible factors, it is possible to identify more concrete stressors and outcomes which are amenable to management and monitoring. This preliminary comparison of conventional and Aboriginal views also demonstrates the potential for FCM as a technique to extract, compare and integrate perspectives of different knowledge systems into health management and policy development.

Association of leisure time physical activity and abdominal obesity with fasting serum insulin and 2-h postchallenge plasma glucose levels

AIMS

We investigated the joint associations of leisure time physical activity and abdominal obesity with fasting insulin and 2-h glucose levels and with the risk of impaired glucose tolerance (IGT) and Type 2 diabetes (Type 2 DM).

METHODS

A cross-sectional population-based random sample of 1812 Finnish adults 45-74 years of age without a history of cardiovascular disease or diabetes. Relative energy expenditure during the previous 12 months (METh/week), assessed by a questionnaire, was used as a measure of leisure time physical activity. Waist-hip ratio (WHR) was used as a measure of abdominal obesity. IGT and Type 2 DM were assessed by a 2-h oral glucose tolerance test and were defined according to the World Health Organization guidelines.

RESULTS

While 2-h glucose and fasting insulin levels increased with increasing WHR (P < 0.001 and P < 0.001, respectively), both of them decreased with increasing physical activity (P = 0.015 and P < 0.001, respectively). The highest 2-h glucose and fasting insulin levels were found among individuals who had most abdominal obesity and were least physically active. Physically inactive individuals had a higher prevalence of IGT and Type 2 DM in all WHR tertiles than physically active persons.

CONCLUSIONS

Higher levels of leisure time physical activity are associated with lower 2-h glucose and fasting insulin levels and a reduced risk of having IGT and Type 2 DM, independent of the level of abdominal obesity.

Increased physical activity reduces prevalence of periodontitis

OBJECTIVES

Physical activity has been shown to have a protective relationship with several chronic diseases. Recently, physical activity was also found to reduce the risk of periodontitis in a study in male health professionals. However, the relationship between physical activity and periodontitis in a diverse group of individuals is not thoroughly examined. The purpose of this study was to examine if there is an association between sustained physical activity and periodontitis in a subset of the third national health and nutrition examination survey (NHANES III).

METHODS

NHANES III participants 18 years of age or older who had had a periodontal examination and reported to have a similar physical activity (or inactivity) level for 10 years or longer were selected (n=2521). Multivariable logistic regression analysis was used to estimate the association between physical activity and periodontitis. The analysis was adjusted for: age, gender, race, education, smoking, body mass index, poverty index, vitamin use, healthy eating index, time since last dental visit, gingival bleeding, and dental calculus.

RESULTS

Engaging in the recommended level of physical activity was significantly associated with lower periodontitis prevalence (OR=0.58, 95% CI, 0.35-0.96). Smoking, however, was found to modify this relationship. The association was strong and significant among never (OR=0.46, 95% CI, 0.23-0.93) and former smokers (OR=0.26, 95% CI: 0.09-0.72), but not among current smokers (OR=1.10, 95% CI: 0.48-2.53).

CONCLUSIONS

These results suggest that engaging in the recommended level of exercise is associated with lower periodontitis prevalence, especially among never and former smokers.

Pediatric obesity and insulin resistance: chronic disease risk and implications for treatment and prevention beyond body weight modification

The study of childhood obesity has continued to grow exponentially in the past decade. This has been driven in part by the increasing prevalence of this problem and the widespread potential effects of increased obesity in childhood on lifelong chronic disease risk. The focus of this review is on recent findings regarding the link between obesity and disease risk during childhood and adolescence. We describe recent reports relating to type 2 diabetes in youth (2), prediabetes (69, 166), metabolic syndrome (33, 35), polycystic ovarian syndrome (77), and nonalcoholic fatty liver disease (58, 146), and the mediating role of insulin resistance in these conditions. In addition, we review the implications of this research for the design of more effective treatment and prevention strategies that focus more on the improvement of obesity-related metabolic abnormalities and chronic disease risk reduction than on the conventional energy balance approach that focuses on weight management.

Lifestyle intervention for the prevention of type 2 diabetes mellitus: putting theory to practice

Type 2 diabetes mellitus is a serious, growing, and costly public health problem. The disease is chronic and degenerative, and thus primary prevention is desirable. Observational studies have linked type 2 diabetes to specific lifestyle behaviors. Several recent major clinical trials confirm that type 2 diabetes can be delayed or prevented in people at high risk; multicomponent lifestyle modification can reduce the incidence of diabetes up to 58%. The American Diabetes Association has recently recommended that lifestyle interventions to prevent or delay diabetes be delivered to people with prediabetes. Delivery of lifestyle interventions in practice is fraught with challenges, but there are several tools and practical strategies available for the implementation of trial findings.

Physical activity and type 2 diabetes: tailoring exercise to optimize fitness and glycemic control

Physical activity decreases insulin resistance and can aid in both preventing type 2 diabetes mellitus and managing the disease. Before patients with type 2 diabetes begin an exercise program, they should undergo a preparticipatory clinical assessment and screening for micro- and macrovascular disease. Patients older than 35 and those with additional cardiovascular risk factors, peripheral vascular disease, long-standing disease, or peripheral neuropathy should have an exercise stress test. Adequate glycemic control and selection of appropriate physical activity, such as brisk walking or swimming, are essential to avoid associated complications. Patients on diabetes medications should monitor blood glucose levels and adjust their diet to minimize fluctuations in blood glucose during exercise.

Weight, adiposity, and physical activity as determinants of an insulin sensitivity index in pima Indian children

OBJECTIVE

To determine whether measures of physical activity are related to an insulin sensitivity index ([ISI] 10(4)/fasting insulin x glucose) independent of weight or adiposity in children.

RESEARCH DESIGN AND METHODS

We conducted a longitudinal study of 90 Pima Indian children (39 boys and 51 girls) at 5 and 10 years of age measuring adiposity (dual-energy X-ray absorptiometry), physical activity behavior (questionnaire: number of activities per week [ACT], average hours per week [TIME]), and energy expenditure (doubly labeled water: physical activity level [PAL]).

RESULTS

In cross-sectional analyses, ACT was correlated with ISI at 5 years of age (r = 0.24, P = 0.02) and at 10 years of age (r = 0.21, P = 0.05), but these relationships were not independent of weight or adiposity. PAL was correlated with ISI at 10 years of age (r = 0.39, P = 0.03) but was not independent of weight or adiposity. Longitudinally, ISI decreased from 5 to 10 years of age, and increases in weight and adiposity were associated with decreases in ISI (r = -0.51 and -0.41, respectively; both P < 0.0001). ACT decreased from 5 to 10 years of age, but children who had smaller decreases in ACT had smaller decreases in ISI, independent of increases in weight or adiposity (partial r = 0.22, P = 0.04 adjusted for either weight or adiposity).

CONCLUSIONS

These data suggest that early establishment and maintenance of an active lifestyle can have a beneficial effect on ISI that is partially independent of changes in weight or adiposity. This is particularly relevant considering the current epidemics of both obesity and type 2 diabetes in children.

Can a physically active lifestyle prevent type 2 diabetes?

Recent clinical trials demonstrated that physical activity plays an important role in type 2 diabetes prevention. Their activity goals resembled public health recommendations: 150 min weekly of moderate intensity physical activity (brisk walking). The flexibility of this goal will make it easier to adopt by individuals of all ages and backgrounds and has the potential for being maintained over time.

Influência da gordura corporal no controle clínico e metabólico de pacientes com diabetes mellitus tipo 2

Avaliamos a influência da gordura corporal (GC) determinada por bioimpedância, índice de massa corpórea (IMC) e a medida da cintura abdominal (CA) em determinadas variáveis clínicas e laboratoriais em 43 pacientes com diabetes tipo 2 (DM2), 26F/17M, pareados pela idade, com 13,6±9,1 anos de duração do DM. As mulheres apresentaram maior IMC: 30,3±5,4 vs. 26,9±2,9kg/m² (p= 0,04), GC: 35,4±6,2 vs. 19,6±6,2% (p= 0,000), níveis de colesterol total (CT): 235±41 vs. 204± 39mg/dL (p= 0,017), triglicerídeos (TG): 146± 61 vs. 116±57mg/dL (p= 0,06) e HbA1c (HPLC): 7,1±1,7 vs. 6,9±1,4% (p= 0,02) do que os homens, não havendo diferença entre HDL e LDL colesterol. A GC correlacionou-se significativamente com os níveis de TG, HbA1c, pressão arterial diastólica (PAD), IMC e CA. Na regressão múltipla com GC, CA e IMC como variáveis independentes e TG (r= 0,34; r²= 0,11; p= 0,02) e PAD (r= 0,39; r²= 0,15; p= 0,008) como dependentes, a GC foi a variável independente significativa. No mesmo modelo com a HBA1c como variável dependente, a GC (r= 0,31; r²= 0,10; p= 0,037) e o IMC (r= 0,43; r²= 0,19; p= 0,01) foram as variáveis significativas. Concluímos que o aumento da GC no paciente com DM2 constituiu um importante fator de risco para piora do controle metabólico e dos níveis tensionais. As mulheres, por terem tido maior percentual de GC e níveis de lipídios, devem ter uma abordagem mais agressiva e diferenciada para sua redução.

Reduction of risk factors following lifestyle modification programme in subjects with type 2 (non-insulin dependent) diabetes mellitus

Exercise and improved diet is known to be beneficial in the management of type 2 (non-insulin dependent) diabetes mellitus. In practice, however, it is difficult for patients to implement these changes unaided. We hypothesized that a lifestyle modification programme involving residential visits would result in beneficial effects on glycaemic control and lipid profile. Three hundred and four individuals with type 2 diabetes participated in a lifestyle modification programme, involving three residential visits (2 weeks, 1 week and one 3-day visit) spaced over 31 weeks. The subjects were all referred for treatment following repeated failure to achieve metabolic control in primary care settings. Participants received information and practical guidance regarding exercise training, nutrition, as well as stress management and psychological counselling. Clinical parameters were determined at each visit. After completion of the programme, subjects showed significant improvements in glycaemic control (P<0.0001). Oxygen uptake was significantly improved (P<0.0001) and blood pressure (P<0.0001), body mass index (P<0.0001) and serum cholesterol (P<0.001) was significantly reduced, while HDL cholesterol (P<0.05) was significantly increased. There were no changes in LDL cholesterol values. Subjects also reported increased well-being and reduced stress. In conclusion, a 31-week lifestyle modification programme results in marked improvements in glycaemic control, blood pressure and well-being in subjects with type 2 diabetes. Thus, this type of lifestyle modification programme is a powerful treatment option to reduce risk factors associated with diabetes and diabetic complications, even in patients who have not responded to conventional diabetic therapy.

[Epidemiology of diabetes and its non-coronary complications]

Diabetes mellitus is among the diseases with great impact on health and society, not only for its high prevalence but also for its chronic complications and high mortality. The most precise method to investigate the prevalence of diabetes is by oral glucose tolerance testing. In Spain, the prevalence of diabetes in the 30-65 year-old population is estimated to be 6.5% among 30-to-65- year old, and 10.3% among the 30-to-89 year-old population. The ratio of known to unknown diabetes ranges from 1:3 to 2:3. The incidence of diabetes mellitus type 2 in Spain is 8/1000 persons per year, and the incidence of type 1 is 11 to 12 cases per 100,000 persons per year. The prevalence of chronic complications varies according to type of diabetes, time since onset and degree of metabolic control: neuropathy 25%, retinopathy 32% and nephropathy 23%. Diabetes is one of the most important causes of death in Spain, occupying third place for women and seventh for men.

Physical activity, physical fitness, and insulin and glucose concentrations in an isolated Native Canadian population experiencing rapid lifestyle change

OBJECTIVE

Little is known about the relation of physical activity and physical fitness to insulin resistance and glucose intolerance in isolated subarctic Native Canadian populations. The purpose of this effort was to examine the relation between activity and fitness and obesity and glucose concentrations in such a unique population.

RESEARCH DESIGN AND METHODS

This study describes 530 men and women from the community of Sandy Lake, Ontario, located in the boreal forest region of central Canada. Fasting blood glucose and insulin concentrations were determined after an overnight fast. Past year physical activity levels were assessed using a modified version of an interviewer-administered questionnaire. Maximal oxygen uptake, a measure of cardiovascular fitness, was estimated using a submaximal step test.

RESULTS

Total (leisure and occupational) physical activity and physical fitness were significantly associated with fasting insulin concentrations after adjusting for age, BMI or percent body fat, waist circumference, and fasting glucose concentration in men but not in women. The relations between physical activity, fitness, and fasting glucose concentrations were not as strong or as consistent as they were when fasting insulin concentration was the dependent variable.

CONCLUSIONS

In this isolated Native Canadian community, both physical activity and fitness were independently associated with fasting insulin concentrations, suggesting a beneficial role of physical activity/fitness on insulin sensitivity that is separate from any influence of activity on body composition. The fact that this relation was found in men but not in women is most likely explained by issues related to the measurement of activity and fitness in this study and the fact that the women in this population appear to be less active than the men.

Current literature in diabetes

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of diabetes/metabolism. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General; 3 Genetics; 4 Epidemiology; 5 Immunology; 6 Prediction; 7 Prevention; 8 INTERVENTION: a&rpar General; b&rpar Pharmacology; 9 Pathology: a&rpar General; b&rpar Cardiovascular; c&rpar Neurological; d&rpar Renal; 10 Endocrinology & Metabolism; 11 Nutrition; 12 Animal Studies; 13 Techniques. Within each section, articles are listed in alphabetical order with respect to author (9 Weeks journals - Search completed at 1st Aug 2001)