Epidemiological studies of exercise in diabetes prevention

CaMKII activity and metabolic imbalance-related neurological diseases: Focus on vascular dysfunction, synaptic plasticity, amyloid beta accumulation, and lipid metabolism

Metabolic syndrome (MetS) is characterized by insulin resistance, hyperglycemia, excessive fat accumulation and dyslipidemia, and is known to be accompanied by neuropathological symptoms such as memory loss, anxiety, and depression. As the number of MetS patients is rapidly increasing globally, studies on the mechanisms of metabolic imbalance-related neuropathology are emerging as an important issue. Ca2+/calmodulin-dependent kinase II (CaMKII) is the main Ca2+ sensor and contributes to diverse intracellular signaling in peripheral organs and the central nervous system (CNS). CaMKII exerts diverse functions in cells, related to mechanisms such as RNA splicing, reactive oxygen species (ROS) generation, cytoskeleton, and protein-protein interactions. In the CNS, CaMKII regulates vascular function, neuronal circuits, neurotransmission, synaptic plasticity, amyloid beta toxicity, lipid metabolism, and mitochondrial function. Here, we review recent evidence for the role of CaMKII in neuropathologic issues associated with metabolic disorders.

Nutritional Avocado Intervention Improves Physical Activity Measures in Hispanic/Latino Families: A Cluster RCT

Introduction

Nutrition and physical activity are key components for the prevention of cardiovascular disease. There remains a paucity of trial data on the effect of specific nutritional interventions on physical activity and sedentary time. One question is how a common nutrient-dense food such as avocado may impact physical activity and sedentary time in Hispanic/Latino families, a group that reports the lowest levels of physical activity.

Design

This is a 6-month clustered RCT.

Setting/participants

Seventy-two families (235 individuals) who identified as Hispanic/Latino were enrolled through the San Ysidro Health Center (San Diego, CA) between April 2017 and June 2018.

Intervention

After a 2-week run-in period, 35 families were randomized to the intervention arm (14 avocados/family/week), and 37 families were assigned to the control arm (3 avocados/family/week).

Main outcome measures

Linear mixed-effects models were used to assess changes in physical activity (MET minutes per week) between the groups during the 6-month trial. Secondary outcomes included sedentary time (minutes/week), BMI, and systolic and diastolic blood pressures.

Results

An adherence goal of >80% was achieved for both arms. Total mean physical activity increased by 2,197 MET minutes per week more in the intervention group (p<0.01) than in the control group, driven by between-group differences in moderate (p<0.01) versus vigorous (p=0.06) physical activity. After accounting for longitudinal repeated measures per participant and nested family effects, total adult physical activity remained significantly higher in the intervention than in the control group (+1,163 MET minutes per week on average per participant), with a significant intervention interaction term (p<0.01). There were no significant changes in sedentary time, BMI, or blood pressure.

Conclusions

Higher allocation of avocados was associated with significantly higher physical activity and no adverse changes in BMI or blood pressure, suggesting that this nutritional intervention may have beneficial pleiotropic effects.Trial registration: This study is registered at www.clinicaltrials.gov as NCT02903433.

Incidence of Parkinson disease in North America

Parkinson disease (PD) is the second most common age-related neurodegenerative condition diagnosed in North America. We recently demonstrated, using multiple epidemiological data sources, that the prevalence of PD diagnoses was greater than previously reported and currently used for clinical, research, and policy decision-making. Prior PD incidence estimates have varied, for unclear reasons. There is a need for improved estimates of PD incidence, not only for care delivery planning and future policy but also for increasing our understanding of disease risk. The objective of this study was thus to investigate the incidence of Parkinson disease across five epidemiological cohorts in North America in a common year, 2012. The cohorts contained data on 6.7 million person-years of adults ages 45 and older, and 9.3 million person-years of adults ages 65 and older. Our estimates of age-sex-adjusted incidence of PD ranged from 108 to 212 per 100,000 among persons ages 65 and older, and from 47 to 77 per 100,00 among persons ages 45 and older. PD incidence increased with age and was higher among males. We also found persistent spatial clustering of incident PD diagnoses in the U.S. PD incidence estimates varied across our data sources, in part due to case ascertainment and diagnosis methods, but also possibly due to the influence of population factors (prevalence of genetic risk factors or protective markers) and geographic location (exposure to environmental toxins). Understanding the source of these variations will be important for health care policy, research, and care planning.

Critical Evaluation of the Case for Pausing California's School-based Fitness Testing

Objective

We undertook a literature review to evaluate the evidence for an association among school-based fitness testing and bullying, weight-based teasing (WBT), and/or gender discrimination.

Methods

We searched the peer-reviewed literature using PubMed, ERIC and GOOGLE Scholar to identify articles related to school-based physical fitness testing (K-12) on the one hand and bullying, WBT, and/or gender discrimination on the other.

Results

We identified 12 studies on the impact of school-based physical fitness testing (PFT) on bullying and WBT. These studies do not support the assertion that PFT places students at elevated risk for bullying and/or WBT as compared to other school settings. There is a dearth of studies investigating an association between PFT and gender discrimination.

Conclusions

The concerns about PFT as a widespread cause of bullying and WBT are not supported by the evidence. It is likely that school climate is a stronger determinant overall of these negative student interactions and that more rigorous teacher training would ameliorate student concerns about fitness testing. Nevertheless, more rigorous research is warranted to determine with confidence that PFT does not elevate students' risks for bullying and WBT and to examine the risks for students with non-binary gender.

Exercise, CaMKII, and type 2 diabetes

Individuals who exercise regularly are protected from type 2 diabetes and other metabolic syndromes, in part by enhanced gene transcription and induction of many signaling pathways crucial in correcting impaired metabolic pathways associated with a sedentary lifestyle. Exercise activates Calmodulin-dependent protein kinase (CaMK)II, resulting in increased mitochondrial oxidative capacity and glucose transport. CaMKII regulates many health beneficial cellular functions in individuals who exercise compared with those who do not exercise. The role of exercise in the regulation of carbohydrate, lipid metabolism, and insulin signaling pathways are explained at the onset. Followed by the role of exercise in the regulation of glucose transporter (GLUT)4 expression and mitochondrial biogenesis are explained. Next, the main functions of Calmodulin-dependent protein kinase and the mechanism to activate it are illustrated, finally, an overview of the role of CaMKII in regulating GLUT4 expression, mitochondrial biogenesis, and histone modification are discussed.

Physical Activity Monitoring in Patients with Neurological Disorders: A Review of Novel Body-Worn Devices

Aim

The aim was to conduct a systematic review to examine the literature reporting the validity and reliability of wearable physical activity monitoring in individuals with neurological disorders.

Method

A systematic search of the literature was performed using a specific search strategy in PubMed and CINAHL. A search constraint of articles published in English, including human participants, published between January 2008 and March 2017 was applied. Peer-reviewed studies which enrolled adult participants with any neurological disorder were included. For the studies which sought to explore the validity of activity monitors, the outcomes measured using the monitor were compared to a criterion measure of physical activity. The studies' methodological quality was assessed using an adapted version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) framework. Data extracted from each study included the following: characteristics of the study participants, study setting, devices used, study protocol/methods, outcomes measured, and the validity/reliability of measurement produced.

Results

Twenty-three studies examining the validity and reliability of 16 different monitors were included. The identified studies comprised participants with a range of different disorders of neurological origin. The available evidence suggests that biaxial or triaxial accelerometer devices positioned around the ankle produce the most accurate step count measurements in patients with neurological disorders. The findings regarding the reliability and validity of activity counts and energy expenditure are largely inconclusive in this population.

Discussion

Ankle-worn biaxial or triaxial accelerometer-type devices provide the most accurate measurement of physical activity. However, further work is required in this field before wearable activity monitoring can be more widely implemented clinically. Standardised activity monitoring protocols are required for implementing these devices in clinical trials and clinical practice, and consensus is required as to the reporting and interpretation of derived variables.

ATIVIDADE FÍSICA E MODULAÇÃO DO RISCO CARDIOVASCULAR

RESUMO Introdução: As doenças cardiovasculares são responsáveis por alto grau de morbidade e mortalidade na população mundial. Em populações saudáveis, a estimativa do risco cardiovascular tem sido calculada a partir de modelos de predição derivados de estudos prospectivos e observacionais. O escore de Framingham é um algoritmo tradicionalmente utilizado como estratégia primária de prevenção de doenças cardiovasculares em pessoas assintomáticas em um período de 10 anos. Para a determinação desse escore são considerados como fatores de risco os níveis séricos de colesterol total, colesterol HDL, pressão sistólica, diabetes mellitus, tabagismo e idade dos pacientes. Objetivo: Avaliar se a prática de atividade física é uma variável importante capaz de modular o risco obtido pelo escore de Framingham. Métodos: Foram considerados dados de 1004 indivíduos, divididos em adultos (18 a 59 anos) e idosos (> 60 anos), usando o software Statistical Package for Social Sciences (SPSS) para as análises estatísticas e adotando-se o nível de significância de 5% (P < 0,05) para todos os testes aplicados. Resultados: A correlação entre os fatores idade, sexo, tabagismo, hipertensão arterial e níveis séricos de HDL e o escore de Framingham foi confirmada tanto no grupo adulto como no idoso. Adicionalmente, nossas análises demonstraram correlação estatisticamente significativa entre a prática de atividade física e o risco calculado por esse escore, ficando evidente que indivíduos adultos ou idosos que praticam atividade física moderada ou intensa apresentam menor risco de desenvolver doença cardiovascular num período de 10 anos. Conclusão: Nossos dados demonstram que a prática de atividade física moderada ou intensa pode modular o escore de Framingham e assim como idade, sexo, tabagismo, hipertensão arterial e níveis séricos de colesterol total e HDL, deve ser considerada entre os fatores de risco de doenças cardiovasculares.

Predictors of cardiorespiratory fitness in female and male adults with different body mass index: National Health and Nutrition Examination Survey 1999-2004 dataset

BACKGROUND

The aim of this study was to explore factors affecting cardiorespiratory fitness in males and females with different body mass index (BMI).

METHODS

The National Health and Nutrition Examination Survey 1999-2004 data were used for this retrospective study. Estimated maximal oxygen uptake (VO_2max) is surrogate for cardiorespiratory fitness (CRF). Univariate and multivariate linear regression analyses were performed to explore whether study variables were associated with estimated VO_2max stratified by gender and BMI categories.

RESULTS

A total of 3292 subjects 20-49 years of age were included in the analysis. CRF significantly decreased as BMI increased in both females and males. Ethnic difference was found in normal BMI in both genders and obese females; homocysteine was significantly negatively associated with estimated VO_2max, as was total cholesterol. Obese male subjects with diabetes had a lower estimated VO_2max than those without diabetes, and C-reactive protein (CRP) level and vitamin B12 level were significantly negatively associated with CRF. Female subjects with diabetes had higher estimated VO_2max than those without diabetes. Folate was significantly positively correlated with estimated VO_2max, whereas CRP was negatively correlated in obese female.

CONCLUSIONS

There are different predictors of CRF in males and females, and in individuals with different BMI. Key messages Different BMI classes are associated with different predictors of cardiorespiratory fitness. Indicators of cardiorespiratory fitness differ between sexes.

Obesity, Prediabetes, and Perceived Stress in Municipal Workers

The primary cause of death for men and women in the United States is heart disease. Obesity and diabetes are major contributors to heart disease, and the risk is worsened in the presence of stress. It is clinically useful to identify predictors of obesity and prediabetes in a working population. The purpose of this current cross-sectional, correlational study was to examine relationships among obesity, prediabetes, and perceived stress in municipal workers using a subset of worksite wellness program data from employees screened in 2010 and 2011. Multiple regression models indicated that age, gender, race, HA1c, shift schedule, physical activity, and occupation were significant predictors of obesity in municipal workers ( p < .01). Prediabetes in municipal workers was predicted by age, Black race, and body mass index (BMI; p < .01). Perceived stress was not a significant predictor of obesity or prediabetes in municipal workers. Overall, the findings of this study provide guidance to occupational health nurses when evaluating individuals in an occupational health setting. Further research is needed to examine relationships among the variables and validate the models.

Physical activity energy expenditure vs cardiorespiratory fitness level in impaired glucose metabolism

AIM/HYPOTHESIS

Little is known about the relative roles of physical activity energy expenditure (PAEE) and cardiorespiratory fitness (CRF) as determinants of glucose regulation. The aim of this study was to examine the associations of PAEE and CRF with markers of glucose metabolism, and to test the hypothesis that CRF modifies the association between PAEE and glucose metabolism.

METHODS

We analysed cross-sectional data from 755 adults from the Danish ADDITION-PRO study. On the basis of OGTT results, participants without known diabetes were classified as having normal glucose tolerance, isolated impaired fasting glycaemia (i-IFG), isolated impaired glucose tolerance (i-IGT), combined IFG + IGT or screen-detected diabetes mellitus. Markers of insulin sensitivity and beta cell function were determined. PAEE was measured using a combined heart rate and movement sensor. CRF (maximal oxygen uptake) was estimated using a submaximal 8 min step test. The associations were examined by linear regression analysis. Results were adjusted for relevant confounders.

RESULTS

PAEE and CRF were reduced in individuals with i-IGT, combined IFG + IGT and screen-detected diabetes mellitus, but were not significantly different in individuals with i-IFG compared with those with normal glucose tolerance. When adjusting CRF for PAEE and vice versa, PAEE and CRF were both associated with lower fasting and 2 h insulin and higher peripheral insulin sensitivity. CRF was additionally associated with lower fasting and 2 h glucose and higher insulin sensitivity and beta cell function. There was no interaction between CRF and PAEE for any markers of glucose metabolism.

CONCLUSIONS/INTERPRETATION

Only CRF, not PAEE, appears to be independently associated with plasma glucose levels and beta cell function, suggesting that CRF may be particularly important for glycaemic control.

Association of cardiorespiratory fitness and overweight with risk of type 2 diabetes in Japanese men

Objective

Existing evidence is limited on what extent fitness can counterbalance type 2 diabetes mellitus (T2DM) risk associated with obesity. We investigated the joint association of weight status and estimated VO_2max, a marker of fitness, with the risk of developing T2DM among Japanese men using haemoglobin A1c and fasting glucose criterion.

Methods

The present study included 3,523 male employees aged 18–61 years without diabetes who provided health check-up and fitness data in Japan in 2003–2005. We calculated hazard ratios and 95% confidence intervals for incident diabetes using the Cox regression model.

Results

During a mean follow-up of 6.0 years, 199 men developed diabetes. Multivariable-adjusted hazard ratios (95% confidence interval) of diabetes were 1.00 (reference), 1.44 (1.01–2.07), and 1.48 (1.03–2.13) for the highest through the lowest tertile of fitness (P for trend  = 0.04). Additional adjustment for body mass index largely attenuated the association of fitness with diabetes. Joint analysis showed that adjusted hazard ratios of diabetes were 1.00, 1.32, 2.94, and 1.83 in normal weight high-fit men, normal weight low-fit men, overweight high-fit men, and overweight low-fit men, respectively.

Conclusion

The results suggest that weight control is more important than fitness in prevention of type 2 diabetes in Japanese men.

Overtime work and prevalence of diabetes in Japanese employees: Japan epidemiology collaboration on occupational health study

Objective

Epidemiologic evidence on long working hour and diabetes has been conflicting. We examined the association between overtime work and prevalence of diabetes among Japanese workers.

Methods

The subjects were 40,861 employees (35,170 men and 5,691 women), aged 16 to 83 years, of 4 companies in Japan. Hours of overtime were assessed using self-reported questionnaires. Diabetes was defined as a fasting plasma glucose ≥126 mg/dl (7.0 mmol/l), hemoglobin A1c ≥6.5% (48 mmol/mol), or current use of anti-diabetic drug. Multiple logistic regression analysis was used to calculate odds ratio of diabetes for each category of overtime.

Results

After adjustment for age, sex, company, smoking, and BMI, there was a suggestion of U-shaped relationship between overtime work and prevalence of diabetes (P for quadratic trend = 0.07). Compared with those who worked <45 hours of overtime per month, the adjusted odds ratios (95% confidence interval) of diabetes were 0.86 (0.77–0.94), 0.69 (0.53–0.89), and 1.03 (0.72–1.46) for those who worked 45–79, 80–99, and ≥100 hours of overtime per month, respectively. In one company (n = 33,807), where other potential confounders including shift work, job position, type of department, alcohol consumption, sleep duration, leisure time physical activity, and family history of diabetes was additionally adjusted for, similar result was obtained (P for quadratic trend = 0.05).

Conclusions

Long hours of overtime work may not be associated with increased prevalence of diabetes among Japanese workers.

Diagnosis and treatment of polycystic ovary syndrome: an Endocrine Society clinical practice guideline

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and treatment of polycystic ovary syndrome (PCOS).

PARTICIPANTS

An Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer developed the guideline.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines. Two systematic reviews were conducted to summarize supporting evidence.

CONCLUSIONS

We suggest using the Rotterdam criteria for diagnosing PCOS (presence of two of the following criteria: androgen excess, ovulatory dysfunction, or polycystic ovaries). Establishing a diagnosis of PCOS is problematic in adolescents and menopausal women. Hyperandrogenism is central to the presentation in adolescents, whereas there is no consistent phenotype in postmenopausal women. Evaluation of women with PCOS should exclude alternate androgen-excess disorders and risk factors for endometrial cancer, mood disorders, obstructive sleep apnea, diabetes, and cardiovascular disease. Hormonal contraceptives are the first-line management for menstrual abnormalities and hirsutism/acne in PCOS. Clomiphene is currently the first-line therapy for infertility; metformin is beneficial for metabolic/glycemic abnormalities and for improving menstrual irregularities, but it has limited or no benefit in treating hirsutism, acne, or infertility. Hormonal contraceptives and metformin are the treatment options in adolescents with PCOS. The role of weight loss in improving PCOS status per se is uncertain, but lifestyle intervention is beneficial in overweight/obese patients for other health benefits. Thiazolidinediones have an unfavorable risk-benefit ratio overall, and statins require further study.

Psychological need satisfaction, intrinsic motivation and affective response to exercise in adolescents

OBJECTIVES

To further understanding of the factors influencing adolescents' motivations for physical activity, the relationship of variables derived from Self-Determination Theory to adolescents' affective response to exercise was examined.

DESIGN

Correlational.

METHOD

Adolescents (N = 182) self-reported psychological needs satisfaction (perceived competence, relatedness, and autonomy) and intrinsic motivation related to exercise. In two clinic visits, adolescents reported their affect before, during, and after a moderate-intensity and a hard-intensity exercise task.

RESULTS

Affective response to exercise and psychological needs satisfaction independently contributed to the prediction of intrinsic motivation in hierarchical linear regression models. The association between affective response to exercise and intrinsic motivation was partially mediated by psychological needs satisfaction.

CONCLUSIONS

Intrinsic motivation for exercise among adolescents may be enhanced when the environment supports perceived competence, relatedness, and autonomy, and when adolescents participate in activities that they find enjoyable.

Evidence for the benefit of exercise therapy in patients with type 2 diabetes

Exercise interventions are recommended in most guidelines for the treatment of type 2 diabetes. Although most guidelines suggest a combination of both aerobic and resistance training, the exact benefits of these interventions remain unclear. Although either modality alone or in combination seems to have an identical impact on glycated hemoglobin levels, resistance training and aerobic training have independent effects on other parameters of cardio-metabolic risk. This review examines the current evidence for aerobic and resistance training on glycemic control, lipid profile, body composition, vascular health, and mental health in patients with type 2 diabetes. The uncertainties surrounding exercise modality, volume and intensity are also addressed.

Mechanistic studies of lifestyle interventions in type 2 diabetes

AIM: To investigate the effect of lifestyle interventions in the non-pharmacological management of type 2 diabetes via a mechanistic approach.

METHODS: A randomized controlled trial was carried out on 60 type 2 diabetic male and female volunteers that fulfilled the inclusion criteria, with their proper consent and permission of the International Electrotechnical Commission for 1 year. 30 patients were included in the test group and 30 patients in the control group. Demographic details, anthropometrical status, physical activity, food habits and blood glucose lipid profile of the volunteers were recorded at baseline, the test group was directed for lifestyle intervention and final blood glucose lipid data were collected at the end of one year of patient follow-up.

RESULTS: After 1 year, the test group who had a lifestyle intervention was found to show a significant improvement in blood glucose lipid profile. The fasting plasma glucose level (FPG), postprandial plasma glucose level (PPG), glycosylated hemoglobin (HbA1c) and body mass index (BMI) values of the test group were reduced significantly, up to 145 ± 2.52, 174 ± 2.59, 6.3 ± 0.32 and 25 ± 0.41 respectively at the end of the study period, in comparison to the control group where FPG, PPG, HbA1c and BMI values were 193 ± 3.36, 249 ± 4.24, 7.2 ± 0.42 and 26 ± 0.65 respectively. Improvement in the total cholesterol (TC), triglyceride (TG), high-density lipoproteins (HDL) and low-density lipoproteins (LDL) values of the test group was also remarkable in comparison to the control group. The TC, TG, HDL and LDL values of the test group were reduced significantly, up to 149 ± 3.32, 124 ± 2.16, 58 ± 0.62 and 118 ± 2.31, respectively.

CONCLUSION: The significant improvement in the blood glucose lipid profile of the test group after 1 year signifies the value of non-pharmacological management of type 2 diabetes via lifestyle intervention strategies.

Exercise and type 2 diabetes: new prescription for an old problem

During the past 50 years, the prevalence of a cluster of chronic, inactivity-related diseases including obesity, insulin resistance and type 2 diabetes mellitus (T2DM), collectively referred to as 'metabolic syndrome' (MetS) has reached global epidemic proportions. Appropriate exercise training is a clinically proven, cost-effective, primary intervention that delays and in many cases prevents the health burdens associated with MetS. Indeed, there is no single intervention with greater efficacy than physical exercise to reduce the risk of virtually all chronic diseases simultaneously. However compliance to National guidelines for physical activity remains low, with "a lack of time" the most frequently cited barrier to exercise participation by adults, irrespective of age, sex and ethnic background. Part of the growing apathy to modify lifestyle habits is that current public health recommendations may be unrealistic and unattainable for the majority of the populace. Hence, there is an urgent need for innovations in exercise prescription that can be incorporated into daily living and induce clinically beneficial health outcomes. Here we focus attention on a novel form of exercise prescription, high-intensity interval training (HIT), and provide evidence that HIT is a time-efficient and well-tolerated therapeutic intervention to improve cardio-metabolic health in a number of pre-clinical and clinical populations.

Patterns of yoga practice and physical activity following a yoga intervention for adults with or at risk for type 2 diabetes

BACKGROUND

The current study described patterns of yoga practice and examined differences in physical activity over time between individuals with or at risk for type 2 diabetes who completed an 8-week yoga intervention compared with controls.

METHODS

A longitudinal comparative design measured the effect of a yoga intervention on yoga practice and physical activity, using data at baseline and postintervention months 3, 6, and 15.

RESULTS

Disparate patterns of yoga practice occurred between intervention and control participants over time, but the subjective definition of yoga practice limits interpretation. Multilevel model estimates indicated that treatment group did not have a significant influence in the rate of change in physical activity over the study period. While age and education were not significant individual predictors, the inclusion of these variables in the model did improve fit.

CONCLUSIONS

Findings indicate that an 8-week yoga intervention had little effect on physical activity over time. Further research is necessary to explore the influence of yoga on behavioral health outcomes among individuals with or at risk for type 2 diabetes.

Change of energy expenditure from physical activity is the most powerful determinant of improved insulin sensitivity in overweight patients with coronary artery disease participating in an intensive lifestyle modification program

The objective was to evaluate the determinants of change (Δ) in insulin sensitivity in overweight coronary artery disease male patients without diabetes after an intensive lifestyle intervention. All patients received nutritional counseling and performed 4 months of exercise training (ET) according to 1 of 2 protocols: aerobic ET (65%-70% of peak aerobic capacity [VO(2)]) 25 to 40 minutes 3 times a week (n = 30) or walking (50%-60% of peak VO(2)) 45 to 60 minutes at least 5 times a week (n = 30). Data from participants of both ET groups were pooled, and post-intensive lifestyle intervention results were compared with baseline data. The primary outcome was Δ insulin sensitivity (m-value) assessed by the criterion standard technique, the euglycemic-hyperinsulinemic clamp. Changes in weight, body mass index, total and percentage fat mass (by dual-energy x-ray absorptiometry scan), waist circumference, total abdominal and visceral fat (by computed tomographic scan), high-sensitivity C-reactive protein, peak VO(2), daily energy intake, and physical activity energy expenditure (PAEE) (by doubly labeled water technique) were also assessed. Daily energy intake decreased by 335 kcal, and PAEE increased by 482 kcal/d (all P < .0001). The mean weight loss was 6.4 kg, and the mean improvement in m-value was 1.6 mg/kg fat-free mass per minute. Univariate determinants of Δ m-value were low baseline PAEE, walking protocol, Δ weight, Δ body mass index, Δ total and percentage fat mass, Δ waist circumference, Δ total abdominal and visceral fat, and Δ PAEE (all P < .05). In multivariate analysis, the only significant determinant of Δ m-value was Δ PAEE (P < .02). In this analysis, the most powerful determinant of improved insulin sensitivity in overweight coronary artery disease patients is the change in PAEE.

Associations of cardiorespiratory fitness and parental history of diabetes with risk of type 2 diabetes

AIMS

We examined the independent and joint associations of cardiorespiratory fitness (CRF) and parental diabetes history on type 2 diabetes risk.

METHODS

A cohort of 11,627 individuals aged 20-79 years was free of baseline diabetes, cardiovascular disease, and cancer. We measured CRF using a maximal treadmill exercise test, and parental diabetes by a medical history questionnaire.

RESULTS

During an average 5.5 year follow-up, 572 cases of type 2 diabetes occurred. Compared with the least fit 20%, the multivariate hazard ratio (HR) (95% CI) was 0.59 (0.43-0.83) for the middle fit 40%, and 0.53 (0.38-0.75) for the high fit 40%. Those with parental diabetes had a 1.40-fold higher risk for developing type 2 diabetes. In combined analyses using fit, no parental diabetes as the referent, unfit with no parental diabetes was 1.79 (95% CI 1.25-2.57) times more likely to develop type 2 diabetes, while the risk with parental diabetes was 1.41 (95% CI 1.12-1.78) and 2.37 (95% CI 1.25-4.49) times higher in the fit and unfit, respectively.

CONCLUSIONS

While high CRF did not fully attenuate the risk of diabetes associated with parental diabetes, being fit reduces diabetes risk regardless of parental history.

Predictors of healthcare professionals' intention and behaviour to encourage physical activity in patients with cardiovascular risk factors

BACKGROUND

Healthcare professionals can play a crucial role in optimizing the health status of patients with cardiovascular risk factors (abdominal obesity, high blood pressure, low HDL cholesterol, elevated triglycerides and elevated blood glucose). In order to do this, it is imperative that we understand the social-cognitive determinants (including habits) that underlie healthcare professionals' intention and the corresponding behavior of actually encouraging patients with cardiovascular risk factors to engage in physical activity.

METHODS

In this longitudinal Professionals' Intention and Behavior (PIB) study, healthcare professionals (N = 278, aged 20-61 years with approximately 60% having attained an education level exceeding bachelor's degree, types of healthcare professionals 60% in physiotherapy and 40% in nursing) completed online surveys measuring the social-cognitive determinants of healthcare professionals' intention and the corresponding behavior of actually encouraging patients with cardiovascular risk factors to engage in physical activity.

RESULTS

Social-cognitive determinants accounted for 41% (p < .001) of the variance in healthcare professionals' intention to encourage physical activity among cardiovascular patients. Important correlates of intention were attitude (β = .443, p < .001), subjective norms (β = .201, p < .001) and perceived behavioral control (β = .137, p < .01). With respect to the self-reported behavior of encouraging patients, social-cognitive determinants accounted for 29% (p < .001) of the variance. Intentions (β = .311 p < .001), habit (β = .163 p < .01), and barriers (β = -.239 p < .001) were significant correlates of professionals' behavior of encouraging patients to engage in physical activity.We explored the congruence between healthcare professionals' intention to encourage patients and the self-reported behavior of encouraging patients. We found that intention and behavior were congruent in 39.7% of the healthcare professionals. Additionally, the intention to encourage and the corresponding behavior of encouraging was incongruent in 31.7% of the healthcare professionals.

CONCLUSIONS

In the prevention of cardiovascular disease, healthcare professionals' intention to encourage physical activity among patients and subsequent behavior of encouraging patients is important for the improvement of patients' cardiovascular risk profiles. We found that the intentions and self-reported behavior of healthcare professionals working with patients with cardiovascular risk factors can be predicted by social-cognitive determinants thus implying that efforts to change and strengthen the intention-behavior relationship of healthcare professionals may have beneficial effects for cardiovascular risk patients (Trial ID: ECP-92).

Scorpion in Combination with Gypsum: Novel Antidiabetic Activities in Streptozotocin-Induced Diabetic Mice by Up-Regulating Pancreatic PPARγ and PDX-1 Expressions

The management of diabetes without any side effects remains a challenge in medicine. In this study, antidiabetic activity and the mechanism of action of scorpion combined with gypsum (SG) were investigated. Streptozotocin-induced diabetic mice were orally administrated with scorpion (200 mg kg(-1) per day) in combination with gypsum (200 mg kg(-1) per day) for 5 weeks. SG treatment resulted in decreased body weight, blood glucose and lipid levels, and increased serum and pancreatic insulin levels in diabetic mice. Furthermore, SG significantly increased the number and volume of beta cells in the Islets of Langerhans and promoted peroxisome proliferator-activated receptor gamma and pancreatic duodenal homeobox 1 expressions in pancreatic tissues. However, scorpion or gypsum alone had no significant effect in this animal model. Metformin showed a slight or moderate effect in this diabetic model, but this effect was weak compared with that of SG. Taken together, SG showed a new antidiabetic effect in streptozotocin-induced diabetic mice. This effect may possibly be involved in enhancing beta-cell regeneration and promoting insulin secretion by targeting PPARγ and PDX-1. Moreover, this new effect of SG offers a promising step toward the treatment of diabetic patients with beta-cell failure as a complementary and alternative medicine.

Upright water-based exercise to improve cardiovascular and metabolic health: a qualitative review

Research regarding the benefits of exercise for cardiovascular and metabolic health is extensive and well-documented. However, weight-bearing exercise may not be suitable for individuals with orthopaedic or musculoskeletal limitations, excess adiposity or other medical conditions. Water-based exercise may provide an attractive alternative to land-based exercise for achieving improved health and fitness in these populations. Although swimming is a popular form of water-based exercise it requires specific skills and is often undertaken at intensities that may not be safely prescribed in patient populations. Therefore upright, water-based exercise has been suggested as a viable water-based alternative. However, surprisingly little is known about the effects of upright water-based exercise on improvements in cardiovascular and metabolic health. Limited evidence from water-based studies indicate that regular deep or shallow water exercise can exert beneficial effects on cardiorespiratory fitness, strength, and body fat distribution. However, the impacts of water-based exercise on lipid profile, bodyweight, and carbohydrate metabolism are still unclear. Further studies are warranted to establish the effects of non-swimming, water-based exercise on cardiometabolic risks in humans.

Cardiovascular risk profile: cross-sectional analysis of motivational determinants, physical fitness and physical activity

BACKGROUND

Cardiovascular risk factors are associated with physical fitness and, to a lesser extent, physical activity. Lifestyle interventions directed at enhancing physical fitness in order to decrease the risk of cardiovascular diseases should be extended. To enable the development of effective lifestyle interventions for people with cardiovascular risk factors, we investigated motivational, social-cognitive determinants derived from the Theory of Planned Behavior (TPB) and other relevant social psychological theories, next to physical activity and physical fitness.

METHODS

In the cross-sectional Utrecht Police Lifestyle Intervention Fitness and Training (UP-LIFT) study, 1298 employees (aged 18 to 62) were asked to complete online questionnaires regarding social-cognitive variables and physical activity. Cardiovascular risk factors and physical fitness (peak VO2) were measured.

RESULTS

For people with one or more cardiovascular risk factors (78.7% of the total population), social-cognitive variables accounted for 39% (p < .001) of the variance in the intention to engage in physical activity for 60 minutes every day. Important correlates of intention to engage in physical activity were attitude (beta = .225, p < .001), self-efficacy (beta = .271, p < .001), descriptive norm (beta = .172, p < .001) and barriers (beta = -.169, p < .01). Social-cognitive variables accounted for 52% (p < .001) of the variance in physical active behaviour (being physical active for 60 minutes every day). The intention to engage in physical activity (beta = .469, p < .001) and self-efficacy (beta = .243, p < .001) were, in turn, important correlates of physical active behavior.In addition to the prediction of intention to engage in physical activity and physical active behavior, we explored the impact of the intensity of physical activity. The intensity of physical activity was only significantly related to physical active behavior (beta = .253, p < .01, R2 = .06, p < .001). An important goal of our study was to investigate the relationship between physical fitness, the intensity of physical activity and social-cognitive variables. Physical fitness (R2 = .23, p < .001) was positively associated with physical active behavior (beta = .180, p < .01), self-efficacy (beta = .180, p < .01) and the intensity of physical activity (beta = .238, p < .01).For people with one or more cardiovascular risk factors, 39.9% had positive intentions to engage in physical activity and were also physically active, and 10.5% had a low intentions but were physically active. 37.7% had low intentions and were physically inactive, and about 11.9% had high intentions but were physically inactive.

CONCLUSIONS

This study contributes to our ability to optimize cardiovascular risk profiles by demonstrating an important association between physical fitness and social-cognitive variables. Physical fitness can be predicted by physical active behavior as well as by self-efficacy and the intensity of physical activity, and the latter by physical active behavior.Physical active behavior can be predicted by intention, self-efficacy, descriptive norms and barriers. Intention to engage in physical activity by attitude, self-efficacy, descriptive norms and barriers. An important input for lifestyle changes for people with one or more cardiovascular risk factors was that for ca. 40% of the population the intention to engage in physical activity was in line with their actual physical active behavior.

The future: genes, physical activity and health

The assigned title for the Lindhard presentation was to examine the future of genes, physical activity and health. The current review is a summary of this presentation. Caution is expressed that technology is improving so rapidly that a future view is limited to a few years as opposed to the 100 years passing since Lindhard's achievements. The near futuristic opportunities and challenges for four major topic topics are reviewed here. Concerns are expressed over current usage of the terms 'control' group and 'non-responders' in exercise research. Our view is that 'control' needs to be differentiated between its usage for treatments of exercise to restore natural functions in individuals with less than healthy levels of physical activity and the inherited genome's expectation for physical activity levels to maintain normal function. For the second discussed topic, it is proposed that the term 'non-responders' should be replaced by the term 'low sensitivity' as there may be no such human who is a non-responder to every exercise adaptation. The third futuristic topic is exercise prescription as envisioned for individualized medicine. However, numerous limitations and challenges exist to truly optimal exercise medicine at the level of one individual. Finally, preventative physical activity medicine is discussed. Physical activity as a therapy now exists to prevent most of the chronic diseases. The future needs to understand the molecular basis for how the body becomes dysfunctional when its level of physical activity does not match the norm of physical activity that selected our inherited genome.

Muscular fitness in relation to physical activity and television viewing among young adults

PURPOSE

To study how time spent in physical activity and that in television (TV) viewing are associated with muscular fitness among young adults.

METHODS

The study population consisted of a cross-sectional sample of 381 males and 493 females aged 19.1 yr (SD 0.3) from the Northern Finland Birth Cohort 1986. Muscular fitness was measured by trunk muscle strength tests (trunk extension, flexion, and rotation) and jumping height test. Time spent on moderate- to vigorous-intensity physical activity and on TV viewing was self-reported by a questionnaire.

RESULTS

The most physically active young adults performed significantly better in most trunk muscle strength tests and the jumping test than the least active subjects. The mean difference between the most and least active groups was at minimum 1.6 kg (95% confidence interval (CI) = -0.5 to 3.7) and at maximum 10.6 kg (95% CI = 4.7-16.5) for different trunk muscle strength tests and at minimum 4.4 cm (95% CI = 2.7-6.1) for the jumping height test. Males and females who watched TV for >or=2 h x d(-1) performed significantly worse in trunk extension and flexion tests and females also performed worse in the jumping test compared with those who watched TV <2 h x d(-1), independent of their physical activity level. The mean difference between low and high TV users was at minimum -3.8 kg (95% CI = -6.7 to -0.9) for trunk extension and flexion strength and -1.2 cm (95% CI = -2.0 to -0.4) for jumping height in females.

CONCLUSIONS

Among young adults, daily TV viewing for >or=2 h, irrespective of physical activity level, was associated with poorer muscular fitness.

Differential relationship between physical activity and progression to diabetes by glucose tolerance status: the Inter99 Study

AIMS/HYPOTHESIS

The aim of the study was to analyse how strongly commuting and leisure-time physical activity affect progression to diabetes and to study whether this relationship is different in individuals with isolated impaired fasting glucose (i-IFG) and isolated impaired glucose tolerance (i-IGT).

METHODS

We studied the incidence of diabetes in 4,031 individuals without diabetes at baseline who participated in the baseline and 5 year follow-up examinations of a population-based primary prevention study, the Inter99 Study. Glucose tolerance status at baseline and at follow-up were based on OGTTs. Commuting and leisure-time physical activity at baseline were assessed by questionnaire. We present rate ratios from Poisson regression analyses adjusted for relevant confounders.

RESULTS

The progression rate to diabetes was lower among physically active individuals in the total study population and particularly among those with i-IGT. The associations were attenuated and lost statistical significance after further adjustment for BMI. We observed no impact of physical activity on the progression to diabetes in individuals with i-IFG.

CONCLUSIONS/INTERPRETATION

Physical activity was associated with a lower progression to diabetes in the total study population and in individuals with i-IGT, a condition primarily characterised by muscle insulin resistance. Physical activity did not predict progression to diabetes in individuals with i-IFG, a condition primarily characterised by hepatic insulin resistance. Our results suggest that there is a differential relationship between physical activity and progression to diabetes among those with i-IFG and i-IGT. Therefore, clinical trials testing the effect of physical activity on progression from i-IFG to diabetes are needed.

TRIAL REGISTRATION

ClinicalTrials.gov ID No.: NCT00289237

FUNDING

The Danish Medical Research Council, the Danish Center for Evaluation and Health Technology Assessment, Novo Nordisk, Copenhagen County, the Danish Heart Foundation, the Danish Diabetes Association, the Danish Pharmaceutical Association, the Augustinus Foundation, the Ib Henriksen Foundation and the Becket Foundation.

Nonpharmacologic therapy and exercise in the prevention of type 2 diabetes

OBJECTIVE

To review the current knowledge about nonpharmacologic approaches in the prevention and early treatment of type 2 diabetes.

RESEARCH DESIGN AND METHODS

This study reviewed the research reports dealing with nonpharmacologic interventions aimed at preventing type 2 diabetes with early lifestyle interventions.

RESULTS

The results from the randomized controlled trials all show that people with impaired glucose tolerance who received enhanced lifestyle advice had significantly lower (on average approximately 50% reduced) incidence of type 2 diabetes compared with those allocated to receive "usual care." Individuals who were able to correct their lifestyle habits as recommended for usual healthy life patterns were mostly protected against type 2 diabetes. Thus, compelling evidence exists that most of the cases of type 2 diabetes can be prevented or at least the onset of the disease can be significantly delayed.

CONCLUSIONS

Randomized controlled trials have unequivocally demonstrated that lifestyle management is highly efficient in the prevention and also in the early management of type 2 diabetes. This evidence of lifestyle modification in diabetes prevention is stronger than for most other multifactorial diseases.

Personality, physical fitness, and affective response to exercise among adolescents

PURPOSE

Evidence shows that aspects of personality are associated with participation in physical activity. We hypothesized that, among adolescents, behavioral activation (BAS) and behavioral inhibition (BIS) systems would be associated with physical fitness (cardiovascular fitness and percent body fat), enjoyment of exercise, tolerance of and persistence in high-intensity exercise, and affective response to an acute exercise bout.

METHODS

One hundred and forty-six healthy adolescents completed a cardiovascular fitness test, percent body fat assessment (dual-energy x-ray absorptiometer), and two 30-min cycle ergometer exercise tasks at moderate and hard intensities. Questionnaires evaluated BIS/BAS, enjoyment of exercise, and preference and tolerance for high-intensity activity. Affect in response to exercise was assessed using the Feeling Scale (FS) and the Activation Deactivation Adjective Check List (AD ACL).

RESULTS

BIS was negatively correlated with cardiovascular fitness and tolerance for high-intensity exercise, and adolescents with high BIS scores reported more negative FS in response to exercise at both moderate and hard intensities. BAS was positively correlated with enjoyment of exercise, and adolescents with high BAS scores reported having more positive FS and higher energetic arousal on the AD ACL in response to moderate-intensity exercise. The association between BAS and affect was attenuated for the hard-intensity exercise task.

CONCLUSION

These findings suggest that both the drive to avoid punishing stimuli (BIS) and the drive to approach rewarding stimuli (BAS) are related to the affective response to exercise. The BIS may be more strongly associated with fitness-related exercise behavior among adolescents than the BAS, whereas the BAS may play a relatively greater role in terms of subjective exercise enjoyment.

Metabolic links between diabetes and Alzheimer's disease

There is a cluster of risk factors for Type 2 diabetes and vascular disease that include high blood glucose, obesity, high blood pressure, increased blood triacylglycerols and insulin resistance. All of these factors, both individually and collectively, increase the risk of Alzheimer's disease (AD) and vascular dementia. Alterations in insulin signaling, glucose and fatty acid metabolism, as well as the accumulation of oxidatively modified and glycated proteins, are associated with both diabetes and the dementias. Data from animal and cell culture models have shown that there is a synergistic interaction between most of these stresses in both AD and diabetes, and with the elevated beta-amyloid peptide levels that are also linked to AD. Some of these parameters can be modified by diet and others may require novel drugs. However, because of the multiplicity of physiological pathways involved, conventional drug therapies directed against a single target are not going to be effective in treating AD or the complications of diabetes. It is therefore likely that the only successful therapy will involve the use of drugs with multiple targets in concert with changes in diet and lifestyle.

Components of the Metabolic Syndrome among a Sample of Overweight and Obese Costa Rican Schoolchildren

Background

The term “pediatric metabolic syndrome” includes a cluster of cardiovascular risk factors such as insulin resistance, dyslipidemia (including increased triglycerides and decreased HDL cholesterol), hypertension, and obesity in children. No studies have been performed on this syndrome in a pediatric population in Costa Rica.

Objective

To establish the prevalence of metabolic syndrome and its components in 8- to 10-year old prepuberal overweight and obese schoolchildren.

Methods

This cross-sectional survey was conducted in 214 overweight and obese boys and girls, aged 8 to 10 years, who were selected from six urban schools from San José, Costa Rica. Anthropometric measurements and determinations of blood glucose, insulin, triglycerides, total cholesterol, HDL cholesterol, and high-sensitivity C-reactive protein (hs-CRP) were performed. The home-ostasis model assessment of insulin resistance (HOMA-IR) index and the Castelli index were calculated to assess insulin resistance and cardiovascular risk, respectively. Social and lifestyle variables were obtained through validated questionnaires.

Results

A total of 110 boys and 104 girls participated in this study; 37.9% of them were overweight and 62.1% were obese. Compared with boys, girls were more sedentary and had higher insulin levels (16.05 ± 10.45 μIU/mL vs. 12.72 ± 7.63 μIU/mL, p = .008), body fat (36.5% vs. 30.9%, p < .001), and HOMA-IR indexes (3.5 ± 2.4 vs. 2.8 ± 1.7, p = .014) but lower HDL cholesterol (0.99 ± 0.23 mmol/L vs. 1.08 ± 0.27 mmol/L, p = .009). Obese children had significantly higher mean serum concentrations of insulin, hs-CRP, and triglycerides and higher insulin resistance (estimated by HOMA-IR) than overweight children, but lower mean serum levels of HDL cholesterol. The prevalence of metabolic syndrome in the study population was 5.6%. Other risk factors for developing cardiovascular disease and type 2 diabetes had high prevalence rates among the children: sedentarism (40.6%), family history of type 2 diabetes (73.3%), high LDL cholesterol levels (≥ 2.84 mmol/L) (57.0%), hyperinsulinemia (> 10.5 μIU/mL) (59.8%), insulin resistance (estimated by HOMA-IR ≥ 2.4) (55.1%), and total cholesterol (> 4.39 mmol/L) (60.7%). Children with metabolic syndrome had significantly higher body mass indexes, glucose levels, and triglyceride levels and lower HDL cholesterol levels than children without metabolic syndrome. Insulin had a very strong positive correlation with HOMA-IR values ( r = 0.982), and hs-CRP had a mild positive correlation with body mass index ( r = 0.296) and body fat ( r = 0.320).

Conclusions

This study reported a prevalence of 5.6% of metabolic syndrome among a sample of Costa Rican overweight and obese prepuberal children. Lifestyle interventions focusing on weight reduction and increasing physical activities should be promoted by education and health authorities in order to avoid the early development and onset of type 2 diabetes and atherosclerosis in childhood.

Prevalence of diabetes and impaired fasting glucose among 769,792 rural Chinese adults

OBJECTIVE

To investigate the prevalence of diabetes and impaired fasting glucose (IFG) among rural Chinese adults.

METHODS

A cross-sectional whole-population health survey of 364781 men and 405011 women aged 35 years and over was undertaken in 2004 in Tianjin rural area. An overnight fasting capillary whole blood specimen was collected for glucose measurement and information on history of previously diagnosed diabetes was obtained by a standard questionnaire.

RESULTS

Using the World Health Organization standard, the age-standardized prevalence of IFG (fasting capillary whole blood glucose 5.6-6.0 mmol/l), screen-detected (previously undiagnosed) diabetes (>or=6.1 mmol/l) and previously diagnosed diabetes were 13.7%, 7.9% and 0.4% in men, 14.5%, 9.7% and 0.9% in women, and 14.1%, 8.8% and 0.7% in men and women combined, respectively. The prevalence of IFG, screen-detected diabetes and previously diagnosed diabetes was higher in women than in men (all p<0.001). The prevalence of IFG and diabetes was higher in participants of rural Tianjin than in the overall Chinese rural and urban population based on the Fourth National Nutritional Survey carried out in 2002.

CONCLUSION

The prevalence of IFG and diabetes is relatively high in the rural population in Tianjin and it has become an important public health problem in China.

Fatty liver is associated with insulin resistance, risk of coronary heart disease, and early atherosclerosis in a large European population

Patients with fatty liver (FL) disease have a high risk of developing diabetes and cardiovascular diseases. The aim was to evaluate the association between FL, insulin resistance (IR), coronary heart disease (CHD) risk, and early atherosclerosis in a large European population (RISC Study). In 1,307 nondiabetic subjects (age 30-60 years) recruited at 19 centers, we evaluated liver enzymes, lipids, insulin sensitivity (by euglycemic-hyperinsulinemic clamp), glucose tolerance (by 75 g oral glucose tolerance test), carotid atherosclerosis as intima media thickness (IMT), CHD risk by the Framingham Heart study prediction score, and physical activity (by accelerometer). The presence of FL was estimated using the fatty liver index (FLI; >60, likelihood >78% presence FL; FLI <20 likelihood >91% absence of FL). Subjects were divided into three groups: G1: FLI <20 (n = 608); G3: FLI >60 (n = 234), G2: intermediate group (n = 465). Compared to G1, G3 included more men (70% versus 24%) and people with impaired glucose tolerance (23% versus 5%). IMT increased with FLI (G3 = 0.64 +/- 0.08 versus G1 = 0.58 +/- 0.08 mm, P < 0.0001). FLI was associated with increased CHD risk (r = 0.48), low-density lipoprotein cholesterol (r = 0.33), alanine aminotransferase (r = 0.48), aspartate aminotransferase (r = 0.25), systolic blood pressure (r = 0.39) and IMT (r = 0.30), and reduced insulin sensitivity (r = -0.43), high-density lipoprotein cholesterol (r = -0.50), adiponectin (r = -0.42), and physical activity (r = -0.16, all P < 0.0001). The correlations hold also in multivariate analysis after adjusting for age, gender, and recruiting center.

CONCLUSION

In middle-age nondiabetic subjects, increased IMT, CHD risk, and reduced insulin sensitivity are associated with high values of FLI.

Preventing type 2 diabetes

The rapid and often relentless progression of type 2 diabetes suggests that high-risk patients should be provided with an equally aggressive strategy to protect their remaining beta-cell function and endogenous insulin secretion. Management of patients with prediabetes should incorporate both lifestyle and pharmacologic intervention. Although no specific recommendations are published for the management of prediabetes, one can assume that preservation of pancreatic beta-cell function, improvement in peripheral insulin resistance and pancreatic insulin secretion, reducing pancreatic alpha-cell secretion of glucagon, preventing long- and short-term diabetes-related complications, and assisting patients to loose weight are beneficial. Aggressive, timely, and physiologic management of prediabetes should be advocated.

Associations of cardiorespiratory fitness and obesity with risks of impaired fasting glucose and type 2 diabetes in men

OBJECTIVE

The purpose of this study was to examine the associations of cardiorespiratory fitness (hereafter fitness) and various obesity measures with risks of incident impaired fasting glucose (IFG) and type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a prospective cohort study of 14,006 men (7,795 for the analyses of IFG), who did not have an abnormal electrocardiogram or a history of heart attack, stroke, cancer, or diabetes.

RESULTS

Of the men, 3,612 (39,610 person-years) and 477 (101,419 person-years) developed IFG and type 2 diabetes, respectively. Compared with the least fit 20% in multivariate analyses, IFG and type 2 diabetes risks in the most fit 20% were 14 and 52% lower, respectively (both P < 0.001). Men with BMI > or =30.0 kg/m2, waist girth >102.0 cm, or percent body fat > or =25 had 2.7-, 1.9-, and 1.3-fold higher risks for type 2 diabetes, respectively, compared with those for nonobese men (all P < 0.01), and the results for IFG were similar. In the combined analyses, obese unfit (least fit 20%) men had a 5.7-fold higher risk for type 2 diabetes compared with normal-weight fit (most fit 80%) men. We observed similar trends for the joint associations of BMI and fitness with IFG and those of waist girth or percent body fat and fitness with both IFG and type 2 diabetes.

CONCLUSIONS

Low fitness and obesity increased the risks of IFG and type 2 diabetes by approximately similar magnitudes. When considered simultaneously, fitness attenuated but did not eliminate the increased risks of IFG and type 2 diabetes associated with obesity, and the highest risk was found in obese and unfit men.

A tailored Internet-plus-email intervention for increasing physical activity among ethnically-diverse women

OBJECTIVE

To evaluate the feasibility and efficacy of an individually tailored, Internet-plus-email physical activity intervention designed for adult women.

METHOD

Healthy and ethnically-diverse adult females (N=156) (mean age=42.8 years, 65% Caucasian) from California were randomly assigned to an intervention (access to a tailored website and weekly emails) or wait-list control group. Participants completed web-based assessments of physical activity, stage of behavior change, and psychosocial variables at baseline, one month, two months, and three months. Data were collected during 2006-2007. Multilevel random coefficient modeling examined group differences in rates of change.

RESULTS

As compared to the control condition, the intervention group increased walking (+69 versus +32 min per week) and total moderate-to-vigorous physical activity (+23 versus -25 min per week) after three months. The intervention did not impact stage of behavior change or any of the other psychosocial variables.

CONCLUSION

A tailored, Internet-based intervention for adult women had a positive effect on walking and moderate-to-vigorous physical activity in an ethnically-diverse sample. However, given the lack of comparable research contact in the control group, these findings should be taken cautiously.

Social and physical environments of sports and exercise reported among adults in the American Time Use Survey

OBJECTIVE

Demographic and temporal patterns in the social and physical environments of sports and exercise in the American Time Use Survey (years 2003-2006) are described.

METHOD

The sample consisted of adult respondents (ages 21+) reporting at least one bout of sports or exercise (N=8844). During the interview, participants reported where (e.g., outdoors, home, work) and with whom (e.g., alone, family, coworkers) each bout occurred. Sample-weighted multinomial logistic regression analyses estimated the adjusted proportion of bouts occurring in each environment by gender, age, education, race/ethnicity, season, weekend/weekday, and time of day.

RESULTS

Among members of the oldest age group (ages 60+), more exercise bouts occurred alone and outdoors compared to younger age groups. Among college graduates, more exercise bouts occurred at a gym/health club compared to groups with lower levels of education. Exercise bouts occurring alone were most likely to happen in the winter, on weekdays, and in the morning. Exercise bouts occurring outdoors were most likely to happen in the summer, on weekend days, and in the morning.

CONCLUSION

Future research and intervention efforts exploring where, when and with whom exercise bouts occur may prove beneficial to addressing public health concerns about physical inactivity.

Cessation of daily wheel running differentially alters fat oxidation capacity in liver, muscle, and adipose tissue

Physical inactivity is associated with the increased risk of developing chronic metabolic diseases. To understand early alterations caused by physical inactivity, we utilize an animal model in which rats are transitioned from daily voluntary wheel running to a sedentary condition. In the hours and days following this transition, adipose tissue mass rapidly increases, due in part to increased lipogenesis. However, whether a concurrent decrease in fatty acid oxidative capacity (FAO) in skeletal muscle, liver, and adipose tissue occurs during this period is unknown. Following 6 wk of access to voluntary running wheels (average distance of approximately 6 km a night), rats were rapidly transitioned to a sedentary state by locking the wheels for 5 h (WL5) or 173 h (WL173). Complete ([(14)C]palmitate oxidation to (14)CO(2)) and incomplete ([(14)C]palmitate oxidation to (14)C-labeled acid soluble metabolites) was determined in isolated mitochondrial and whole homogenate preparations from skeletal muscle and liver and in isolated adipocytes. Strikingly, the elevated complete FAO in the red gastrocnemius at WL5 fell to that of rats that never ran (SED) by WL173. In contrast, hepatic FAO was elevated at WL173 above both WL5 and SED groups, while in isolated adipocytes, FAO remained higher in both running groups (WL5 and WL173) compared with the SED group. The alterations in muscle and liver fat oxidation were associated with changes in carnitine palmitoyl transferase-1 activity and inhibition, but not significant changes in other mitochondrial enzyme activities. In addition, peroxisome proliferator-activated receptor coactivator-1alpha mRNA levels that were higher in both skeletal muscle and liver at WL5 fell to SED levels at WL173. This study is the first to demonstrate that the transition from high to low daily physical activity causes rapid, tissue-specific changes in FAO.

Insulin resistance and impaired glucose tolerance in overweight and obese Costa Rican schoolchildren

BACKGROUND

Worldwide obesity has become an unprecedented public health challenge. In addition, a notable increase in the risk of insulin resistance and type 2 diabetes mellitus has emerged. In Costa Rica, there are no epidemiological data to establish the prevalence of type 2 diabetes in the pediatric population. However, information from the Endocrinology Department of the Children's National Hospital indicates an increased number of cases in the last 2 to 3 years.

OBJECTIVE

To determine the prevalence of insulin resistance and impaired glucose tolerance in overweight and obese schoolchildren.

METHODS

This cross-sectional study was conducted among 214 healthy 8- to 10-year-old children from urban schools of San José, Costa Rica. Anthropometric measurements and blood determinations of glucose, insulin, proinsulin, glycosylated hemoglobin, C-peptide, and leptin were performed. Indexes were calculated to assess insulin resistance. Information on social and lifestyle variables was obtained from questionnaires, and acanthosis nigricans was certified by a physician. Statistical analysis was performed with SPSS software for Windows, version 10.0.

RESULTS

The prevalence of type 2 diabetes mellitus was very low (0.5%) in the studied population. However, hyperinsulinemia and impaired glucose tolerance were present in 20.6% and 6.5% of the subjects, respectively. On the basis of the Fasting Glucose-to-Insulin Resistance Ratio (FGIR), 46.7% of the children showed insulin resistance. Girls and obese children (body mass index > or = 95th percentile) were more likely to have higher serum insulin levels and insulin resistance than boys and overweight children (BMI > or = 85th percentile). Compared with the lowest quintile, children in the highest quintile of body-fat tissue had higher insulin resistance but had similar serum concentrations of glucose, C-peptide, and proinsulin. Positive family histories of type 2 diabetes mellitus and sedentarism (73.7% and 40.7%, respectively) were highly prevalent among overweight and obese children.

CONCLUSIONS

The prevalence of impaired glucose tolerance and insulin resistance in obese children indicates a worrisome trend in the incidence of type 2 diabetes in Costa Rica. Strategies for weight reduction, obesity prevention, and promotion of healthy lifestyles are necessary to prevent the onset of type 2 diabetes during childhood and adolescence.

How should the clinician most effectively prevent type 2 diabetes in the obese person at high risk?

The dramatic increase in newly diagnosed cases of type 2 diabetes (T2D) has developed into a major public health concern worldwide. Conversely, several clinical studies have demonstrated that preventive efforts can significantly reduce the risk of developing diabetes. There is a clear consensus that action is needed to develop targeted community-based prevention programs and strategies for T2D. Currently, numerous prevention management concepts that can be implemented into clinical practice exist in various countries. Finland is the pioneer country in implementing community-wide diabetes prevention programs. Nevertheless, population-based nationwide strategies are still lacking in virtually all countries. We report on intervention strategies to prevent T2D in people with increased diabetes risk, as well as strategies on how to implement diabetes prevention programs into the real world of public health or clinical care. The implementation of managed prevention concepts will realistically help to improve the ability to prevent T2D in the public health framework.