Association of the metabolic syndrome with both vigorous and moderate physical activity

Fructose-rich diet leads to reduced aerobic capacity and to liver injury in rats

The main purpose of this research was to investigate the alterations in the aerobic capacity and appearance of metabolic alterations in Wistar rats fed on fructose-rich diet. We separated twenty-eight rats into two groups according to diet: a control group (C) (balanced diet) and a fructose-rich diet group (F). The animals were fed these diets for 60 d (d 120 to 180). We performed insulin, glucose as well as a minimum lactate test, at d 120 and 180. At the end of the experiment, sixteen animals were euthanized, and the following main variables were analysed: aerobic capacity, the serum aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio, serum and liver triglyceride concentrations, serum and liver thiobarbituric acid reactive substance (TBARS) concentrations, serum and liver catalase and superoxide dismutase (SOD) activity and haematoxylin-eosin histology (HE) in hepatocytes. The remaining twelve animals were submitted to an analysis of their hepatic lipogenic rate. The animals fed a fructose-rich diet exhibited a reduction in aerobic capacity, glucose tolerance and insulin sensitivity and increased concentrations of triglycerides and TBARS in the liver. Catalase and SOD activities were reduced in the livers of the fructose-fed animals. In addition, the serum AST/ALT ratio was higher than that of the C group, which indicates hepatic damage, and the damage was confirmed by histology. In conclusion, the fructose-rich diet caused significant liver damage and a reduction in insulin sensitivity in the animals, which could lead to deleterious metabolic effects.

Metabolic and cardiac autonomic effects of high-intensity resistance training protocol in Wistar rats

The aim of this study was to assess the effects of metabolic and autonomic nervous control on high-intensity resistance training (HRT) as determined by pancreatic glucose sensitivity (GS), insulin sensitivity (IS), blood lactate ([La]), and heart rate variability (HRV) in rats. Thirty male, albino Wistar rats (292 ± 20 g) were divided into 3 groups: sedentary control (SC), low-resistance training (LRT), and HRT. The animals in the HRT group were submitted to a high-resistance protocol with a progressively increasing load relative to body weight until exhaustion, whereas the LRT group performed the same exercise regimen with no load progression. The program was conducted 3 times per week for 8 weeks. The [La], parameters related to the functionality of pancreatic tissue, and HRV were measured. There was a significant increase in peak [La] only in the HRT group, but there was a reduction in [La] when corrected to the maximal load in both trained groups (LRT and HRT, p < 0.05). Both trained groups exhibited an increase in IS; however, compared with SC and LRT, HRT demonstrated a significantly higher GS posttraining (p < 0.05). With respect to HRV, the low-frequency (LF) band, in milliseconds squared, reduced in both trained groups, but the high-frequency band, in milliseconds squared and nu, increased, and the LF in nu, decreased only in the HRT group (p < 0.05). The HRT protocol produced significant and beneficial metabolic and cardiac autonomic adaptations. These results provide evidence for the positive benefits of HRT in counteracting metabolic and cardiovascular dysfunction.

Influence of change in aerobic fitness and weight on prevalence of metabolic syndrome

Introduction

The metabolic syndrome is the clustering of several cardiometabolic risk factors that can lead to the development of coronary heart disease and type 2 diabetes. We evaluated whether a change in aerobic fitness resulting from a lifestyle intervention could significantly change the odds of metabolic syndrome prevalence.

Methods

Participants (n = 810) were recruited into PREMIER, a multicenter, randomized, controlled clinical trial with outcome assessments at 6 and 18 months. The primary eligibility criterion was a diagnosis of prehypertension or stage 1 hypertension. PREMIER randomized participants to 2 lifestyle interventions, both of which included increased physical activity, or an advice-only control group. Participants completed a submaximal treadmill exercise test; we used reduction in heart rate as the measure of improved aerobic fitness. We used logistic regression to determine intervention effects on metabolic syndrome prevalence. Our models controlled for dietary pattern change.

Results

The lifestyle interventions had no significant effect on metabolic syndrome prevalence at 6 months or 18 months. When combining intervention and control groups, at 6 and 18 months, a 1-beat-per-minute reduction in heart rate was associated with a 4% reduction in prevalence of metabolic syndrome (P < .001). When we tested for weight change as a mediator, the association was no longer significant.

Conclusion

Increased aerobic fitness may reduce prevalence of metabolic syndrome. This association appears to be mediated through concomitant weight change.

Prevalence and anthropometric risk of metabolic syndrome in taiwanese adolescents

Background. To evaluate the prevalence and the importance of anthropometric indexes on metabolic syndrome (MetS) among young adolescents in Taiwan. Methods. We conducted a cross sectional survey to obtain a representative sampling among Taipei adolescents in 2003, totally enrolled of 1,562 adolescents (764 boys and 798 girls) from age 11 to 15. We used modified NCEP-ATP III criteria to diagnose metabolic syndrome in young adolescents including: blood pressure ≧90th percentile, fasting glucose ≧90th, TG ≧ 90th, HDL-C ≦ 10th, and BMI or WC ≧ 90th according to age and gender specific recommendations. Results. The overall prevalence of MetS was 4.8% for boys and 3.9% for girls. BMI and WC were significantly associated with MetS for both boys and girls, even after adjusting for age, cigarette smoking, alcohol drinking and pubertal status. However, after further adjusting for BMI or WC, WC for boys (OR = 1.14, 95% CI = 1.05–1.24) and BMI for girls (OR = 1.36, 95% CI = 1.13–1.64) were significantly associated with MetS. Conclusions. Adolescents with abnormal BMI or waist circumference had 10 to 20 times higher odds of MetS when compared to normal subjects. Obesity, either general or central adiposity, may play an important role in the development of MetS among adolescents.

Metabolic syndrome in adult cancer survivors: a meta-analysis

BACKGROUND

Cross-sectional studies have reported inconsistent findings on whether the risk of metabolic syndrome is high among cancer survivors. We conducted a meta-analysis of cross-sectional studies.

METHODS

We searched MEDLINE (PubMed) and EMBASE in April 2010. Two evaluators independently reviewed and selected articles, based on pre-determined selection criteria.

RESULTS

Out of 257 articles meeting our initial criteria, 9 cross-sectional studies, which involved 6763 participants (1762 cases and 5001 controls) were included in the final analysis. Compared with the healthy control groups, the cancer survivors were at an increased risk of metabolic syndrome, in the random-effects meta-analysis of all 9 cross-sectional studies (OR=1.84; 95% CI=1.14-2.97; I(2)=80.5). In the subgroup meta-analysis by cancer type, a significant positive association was observed for hematologic malignancies, including ALL (acute lymphoblastic leukemia), AML (acute myelogenous leukemia), NHL (non-Hodgkin's lymphoma), and CML (chronic myelogenous leukemia) (OR=1.94; 95% CI=1.06-3.55; I(2)=68.1%), whereas no significant association was found for non-hematologic malignancies, including testicular tumor, prostate cancer, sarcoma, and epithelial ovarian cancer.

CONCLUSIONS

Our meta-analyses of cross-sectional studies found that adult cancer survivors with hematologic malignancies were at an increased risk of metabolic syndrome.

Physical exercise in southern Germany: a cross-sectional study of an urban population

OBJECTIVES

The aim of this study was to investigate the degree of physical exercise and self-assessment of physical fitness (PF) and their relationship to health- and behaviour-specific factors in a randomly selected sample of an urban population in southern Germany.

DESIGN

Cross-sectional study.

SETTING

In the southern German city of Leutkirch.

PARTICIPANTS

2187 subjects randomly selected from the registry of inhabitants. Of the selected group, aged 18-65 years, 52.1% were women and 47.9% men.

PRIMARY AND SECONDARY OUTCOME MEASURES

Participants were asked how many hours per week they spent on physical exercise and sports. They were also asked to rate their own performance and/or PF.

RESULTS

Overall, 38.9% of the participants reported no physical exercise. Men reported a higher level of physical exercise than did women. Less exercise was reported by subjects with diabetes, high body mass index and waist-to-hip ratio and by those who were underweight. Alcohol consumption, smoker status and higher educational level showed a positive association with physical exercise. A negative trend with respect to moderate physical exercise was observed for those with metabolic syndrome, diabetes, hypertension and hepatic steatosis, but this was statistically significant only for subjects with diabetes. In both men and women, there was a relationship between self-assessed 'good' PF and high physical exercise.

CONCLUSIONS

The data show that a large proportion of the study population is not physically active; specific risk groups (overweight subjects, older subjects, smokers or subjects with low educational level) are even less active. The data suggest that there is a great potential for measures promoting physical exercise in these groups.

Interaction of physical activity level and metabolic syndrome among the adult Asian Indians living in Calcutta, India

OBJECTIVES

The present community-based cross-sectional study was aimed to study the interaction of physical activity level (PAL) and metabolic syndrome (MS) among the adult Asian Indians.

METHODS

A total of 448 adult (> 30 years) individuals (males and females) inhabiting in and around Calcutta, India participated in the study. Anthropometric measures, blood pressure, metabolic profiles and intake of dietary fatty acids were obtained from participants using standard guidelines. Metabolic syndrome (MS) was defined accordingly. The dietary intake (gram/week) of fatty acids namely total fat (TFA); saturated fatty acids (SFA); monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) were obtained using nutritive values of Indian foodstuffs. Physical activity level (PAL) was categorized in to three different level: 1) high PAL - who exercised regularly and had physically demanding occupation 2) moderate PAL - who either exercised regularly or had physically demanding occupation, and 3) low PAL - who neither exercised regularly nor had physically demanding occupation.

RESULTS

The prevalence of MS was found to be inversely related with PAL. Individuals with low PAL had higher prevalence of MS as compared to their counterparts. Moreover individuals with low PAL had significantly higher BMI, WC, WHR as well as TFA and SFA than individuals with moderate and high PAL.

CONCLUSION

PAL is playing a vital role in the constellation of risk factors associated with MS. Habitual physical activity may be beneficial to prevent growing incidence of MS phenotypes in people of Asian Indian origin.

Dietary, behavioural and socio-economic determinants of the metabolic syndrome among adults in Luxembourg: findings from the ORISCAV-LUX study

OBJECTIVE

The purpose of the present research was to investigate the epidemiological profile of the metabolic syndrome (MetS) and to explore its potential dietary, behavioural and socio-economic determinants among European adults residing in Luxembourg.

DESIGN

Cross-sectional, population-based ORISCAV-LUX survey.

SETTING

European adults aged 18-69 years residing in Luxembourg.

SUBJECTS

A total of 1349 Europid adults, who participated in the ORISCAV-LUX survey, were included in the study. The prevalence of MetS was estimated according to the Revised-Adult Treatment Panel (R-ATPIII) criteria. Multivariate logistic regression was used to identify the dietary, behavioural and socio-economic factors independently associated with MetS.

RESULTS

The overall prevalence of MetS was 24.7 % with significant gender difference (18.5 % for women v. 30.8 % for men, P < 0.0001). Age, male gender, primary level of education, physical inactivity, family history of diabetes and hypertension and inadequate protein intake were identified as significant determinants of MetS, after adjusting for other socio-economic, family medical history and lifestyle factors.

CONCLUSIONS

MetS is a common condition among Europid adults in Luxembourg and increases dramatically with age, in both genders. Several dietary, socio-economic and behavioural factors explain the disparity observed. These findings highlight the importance of a comprehensive approach to MetS encompassing dietary, lifestyle and socio-economic aspects, both in clinical and community settings.

Association between physical activity and metabolic syndrome in middle-aged Japanese: a cross-sectional study

BACKGROUND

Although many studies have reported an association between self-reported physical activity and metabolic syndrome (MetS), there is limited information on the optimal level of physical activity required to prevent MetS. This study aimed to determine the association between objectively measured physical activity and MetS in middle-aged Japanese individuals. We also determined the optimal cutoff value for physical activity required to decrease the risk of developing MetS.

METHODS

A total of 179 men and 304 women, aged between 30 and 64 years, participated in this study. Participants were divided into two groups using the Japanese criteria for MetS as those with MetS or pre-MetS, and those without MetS. Participants were considered to be physically active if they achieved a physical activity level of 23 metabolic equivalents (METs) h/week, measured using a triaxial accelerometer. The association between physical activity and MetS was analyzed using logistic regression with the following covariates: sex, age, sedentary time, low intensity activity, calorie intake, smoking, menopause and body mass index. We also evaluated the factors that determined the association between the prevalence of MetS and pre-MetS and the physical activity cutoff value using classification and regression tree (CART) analysis.

RESULTS

The odds ratio for MetS and pre-MetS was 2.20 for physically inactive participants (< 23 METs h/week), compared with physically active participants (≥ 23 METs h/week). The corresponding odds ratios for men and women were 2.27 (P < 0.01) and 1.95 (not significant), respectively. CART analyses revealed that moderate-vigorous physical activity of > 26.5 METs h/week was sufficient to decrease the prevalence of MetS and pre-MetS in middle-aged Japanese men and women.

CONCLUSIONS

The results of this cross-sectional study indicate that the Exercise and Physical Activity Reference for Health Promotion 2006 is inversely associated with the prevalence of MetS in men. Our results also suggest that moderate physical activity of > 26.5 METs h/week may decrease the risk of developing MetS and pre-MetS in middle-aged Japanese individuals.

Alcohol use behaviors and risk of metabolic syndrome in South Korean middle-aged men

Background

It is thought that small volumes of alcohol may have positive effects on health. However, excessive drinking results in serious health problems. An accurate method to determine individual alcohol use behaviors are needed to assess objectively the extent to which drinking affects health. This study investigated the association between risk of metabolic syndrome (MetS) and alcohol use behaviors in middle-aged South Korean men using the Alcohol Use Disorders Identification Test.

Methods

This study used data from the South Korea National Health and Nutrition Examination (KNHANES) IV (2008), which extracted the standard survey household by using the proportional systematic sampling method. Data of 714 participants from KNHANES IV, 2008 were analyzed using Surveyfreq and Surveylogistic regression to investigate the association between MetS and alcohol use behaviors in middle-aged South Korean men.

Results

After adjustment for education, smoking, and physical activity, alcohol use behaviors were significantly associated with an increased risk of hypertension [odds ratio (OR) = 2.54, 95% confidence interval (CI) = 1.5-4.06 in the hazardous group; OR = 2.99, 95% CI = 1.84-4.92 in the problem group]; impaired fasting glucose (OR = 2.15, 95% CI = 1.16-3.99 in the hazardous group; OR = 2.48, 95% CI = 1.42-4.33 in the problem group); dyslipidemia (OR = 2.19, 95% CI = 1.38-3.47 in the problem group); abdominal obesity (OR = 1.93, 95% CI = 1.17-3.19 in the hazardous group; OR = 1.85, 95% CI = 1.17-2.92 in the problem group); and MetS (OR = 2.16, 95% CI = 1.24-3.77 in the hazardous group; OR = 2.54, 95% CI = 1.41-4.58 in problem group).

Conclusions

This study found that excessive alcohol use behaviors increased the risk of hypertension, diabetes, dyslipidemia, abdominal obesity, and MetS. Considering the rising rate of alcohol consumption and heavy drinking at single sittings, a culture of less risky alcohol consumption must be established to promote health among middle-aged men.

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).

Exercise counteracts fatty liver disease in rats fed on fructose-rich diet

BACKGROUND

This study aimed to analyze the effects of exercise at the aerobic/anaerobic transition on the markers of non-alcoholic fatty liver disease (NAFLD), insulin sensitivity and the blood chemistry of rats kept on a fructose-rich diet.

METHODS

We separated 48 Wistar rats into two groups according to diet: a control group (balanced diet AIN-93 G) and a fructose-rich diet group (60% fructose). The animals were tested for maximal lactate-steady state (MLSS) in order to identify the aerobic/anaerobic metabolic transition during swimming exercises at 28 and 90 days of age. One third of the animals of each group were submitted to swimming training at an intensity equivalent to the individual MLSS for 1 hours/day, 5 days/week from 28 to 120 days (early protocol). Another third were submitted to the training from 90 to 120 days (late protocol), and the others remained sedentary. The main assays performed included an insulin tolerance test (ITT) and tests of serum alanine aminotransferase [ALT] and aspartate aminotransferase [AST] activities, serum triglyceride concentrations [TG] and liver total lipid concentrations.

RESULTS

The fructose-fed rats showed decreased insulin sensitivity, and the late-exercise training protocol counteracted this alteration. There was no difference between the groups in levels of serum ALT, whereas AST and liver lipids increased in the fructose-fed sedentary group when compared with the other groups. Serum triglycerides concentrations were higher in the fructose-fed trained groups when compared with the corresponding control group.

CONCLUSIONS

The late-training protocol was effective in restoring insulin sensitivity to acceptable standards. Considering the markers here evaluated, both training protocols were successful in preventing the emergence of non-alcoholic fatty liver status disease.

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.

Physical activity and obesity gap between black and white women in the southeastern U.S

BACKGROUND

Differences between black and white women in the associations of sedentary and active behaviors and obesity are mostly unknown.

PURPOSE

To examine associations of sedentary and active behaviors with BMI, a marker of overall obesity, in a large group of black and white women and to determine whether there are differences by race in these associations.

METHODS

Associations between time spent in sedentary and active behaviors and BMI were examined using cross-sectional data collected from 2002 to 2006 at enrollment into the Southern Community Cohort Study (SCCS) from 22,948 black and 7830 white women living in the southeastern U.S. These associations were examined using linear and polytomous logistic regression models controlling for age, race, income, education, occupational status, tobacco use, marital status, and comorbidities.

RESULTS

Time spent in sedentary behaviors was directly related to BMI whereas time spent in active behaviors such as moderate and vigorous physical activity was inversely related to BMI, with stronger associations for whites than blacks. White women in the highest quartile of sedentary behaviors were more likely to be moderately (BMI=30-39) or severely (BMI>40) obese than women in the lowest quartile (OR=2.3, 95% CI=1.8, 2.9 for moderate, and OR=4.0, 95% CI=3.1, 5.3 for severe obesity), whereas the ORs among similarly sedentary black women were modestly elevated (ORs of 1.4, 95% CI=1.2, 1.6; and 1.6, 95% CI=1.4, 1.8).

CONCLUSIONS

There are significant differences in the association of physical activity patterns and obesity between black and white women living in the southeastern U.S. Although most guidelines for prevention of obesity and maintaining weight promote increased time in moderate and vigorous physical activity, these results indicate that a reduction in sedentary behavior time may represent another useful strategy in this population.

"Proportion explained": a causal interpretation for standard measures of indirect effect?

The assessment of indirect effects is an important tool for epidemiologists interested in exploring the mechanisms of exposure-disease relations. A standard way of expressing an indirect effect is in terms of the "proportion explained"; this is the proportion of the total effect that is explained by a particular mediator (or set of mediators). There are several ways to calculate the proportion explained, based on both additive and multiplicative models. However, these standard methods (particularly those based on multiplicative models) have been criticized for lacking a causal interpretation. To address this issue, the author uses a framework of potential outcomes to define the indirect effects of interest (natural effects) and assess the correspondence between the natural effects and standard measures. The author finds that standard additive measures represent an unbiased weighted average of the effects of interest; standard multiplicative measures, on the other hand, yield a biased weighted average of these effects. If the investigator is primarily interested in whether or not an indirect effect exists, standard measures for mediation will often yield the correct answer. In contrast, if valid quantification of the indirect effect is desired, counterfactual-based methods should be used.

Trajectories of entering the metabolic syndrome: the framingham heart study

BACKGROUND

We evaluated the progression of the metabolic syndrome (MetS) and its components, the trajectories followed by individuals entering MetS, and the manner in which different trajectories predict cardiovascular disease and mortality.

METHODS AND RESULTS

Using data from 3078 participants from the Framingham Offspring Study (a cohort study) who attended examinations 4 (1987), 5 (1991), and 6 (1995), we evaluated the progression of MetS and its components. MetS was defined according to the Adult Treatment Panel III criteria. Using logistic regression, we evaluated the predictive ability of the presence of each component of the MetS on the subsequent development of MetS. Additionally, we examined the probability of developing cardiovascular disease or mortality (until 2007) by having specific combinations of 3 that diagnose MetS. The prevalence of MetS almost doubled in 10 years of follow-up. Hyperglycemia and central obesity experienced the highest increase. High blood pressure was most frequently present when a diagnosis of MetS occurred (77.3%), and the presence of central obesity conferred the highest risk of developing MetS (odds ratio, 4.75; 95% confidence interval, 3.78 to 5.98). Participants who entered the MetS having a combination of central obesity, high blood pressure, and hyperglycemia had a 2.36-fold (hazard ratio, 2.36; 95% confidence interval, 1.54 to 3.61) increase of incident cardiovascular events and a 3-fold (hazard ratio, 3.09, 95% confidence interval, 1.93 to 4.94) increased risk of mortality.

CONCLUSIONS

Particular trajectories and combinations of factors on entering the MetS confer higher risks of incident cardiovascular disease and mortality in the general population and among those with MetS. Intense efforts are required to identify populations with these particular combinations and to provide them with adequate treatment at early stages of disease.

The Influence of Exercise on Metabolic Syndrome in Youth: A Review

The metabolic syndrome (MetS) is a clustering of dyslipidemia, hypertension, glucose intolerance, and central obesity or waist circumference that places individuals at high risk for developing cardiovascular or heart disease. Although first characterized in adults, it has been found in children, but the definition of MetS in children is still controversial. Although MetS is most closely associated with obesity in children, 2 factors believed to affect MetS are physical activity (PA) and aerobic power or fitness. Studies using accelerometry to estimate PA of children have shown that low levels are associated with increased risk of developing MetS. Conversely, high levels of PA at moderate to vigorous intensities reduce the risk. Similarly, low levels of aerobic fitness increase the likelihood of developing MetS. These effects appear to be independent of obesity. Studies have also shown that interventions that increase PA levels and improve aerobic fitness cause a reduction in MetS risk; however, an exact prescription for exercise cannot be presently provided. This review provides an in-depth analysis of what is presently known about the relationship between MetS and PA and aerobic fitness in children. In addition, information is presented regarding potential mechanisms for exercise to affect the major markers of MetS.

Association between physical activity and metabolic syndrome in Iranian adults: national surveillance of risk factors of noncommunicable diseases (SuRFNCD-2007)

Metabolic syndrome (MetS) is a common health problem in developing countries. We aimed to assess the association between different aspects of physical activity and MetS in our country. A standardized international questionnaire (Global Physical Activity Questionnaire) recommended by the World Health Organization was used in the third national survey of risk factors of noncommunicable diseases (SuRFNCD-2007) to collect physical activity data from a nationally representative sample of Iranian adults. Physical activity was evaluated in 3 domains: work, commuting, and recreational activities. Both duration and intensity of activity were considered. Biochemical measurements were carried out, and MetS was defined by the International Diabetes Federation and the Adult Treatment Panel III criteria. The data collected from a total of 3296 individuals were analyzed. The national prevalence of MetS was estimated to be between 24% and 30%, depending on sex and the criteria used. The prevalence of MetS among individuals with high-, moderate-, and low-category activity was 18.7% +/- 1.5%, 25.8% +/- 2.0%, and 27.9% +/- 2.0%, respectively (P < .001). These rates were 12.6% +/- 1.6%, 26.0% +/- 1.5%, and 34.1% +/- 3.2% among individuals with vigorous activity, with nonvigorous activity, and without activity, respectively (P < .001). We demonstrated a significant linear association between the number of metabolic abnormalities and lower levels of various aspects of physical activity (total physical activity, duration of domain-specific activity, and duration of intensity-specific activity; P < .001 for all). Notably, the risk for MetS increased 1.28-fold with every 30-min/d reduction in vigorous-intensity activity (95% confidence interval = 1.15-1.42, P < .001). The results of the present study should be considered for future public health programs in Iran.

Gender differences relating to metabolic syndrome and proinflammation in Finnish subjects with elevated blood pressure

Fasting insulin, adiponectin, high-sensitivity C-reactive protein (hs-CRP), and interleukin-1 receptor antagonist (IL-1Ra) were determined in 278 men and 273 women with blood pressure > or = 130 and/or > or = 85 mmHg and/or with antihypertensive medication. Metabolic syndrome (MetS) with the National Cholesterol Education Program (NCEP) criteria was observed in 35% of men and 34% of women. Men with MetS had lower hs-CRP and IL-1Ra than women. The absolute gender difference in adiponectin was smaller and those in IL-1Ra and hs-CRP were greater in subjects with MetS compared to those without. After adjustment with body mass index the association between insulin and the odd's ratio (OR) for MetS remained significant in both genders, in females also the association between the OR for MetS and adiponectin. There are gender differences in subjects with elevated blood pressure and MetS with respect to inflammatory markers and the relationship between adiponectin levels and MetS.

Physical activity and risk of metabolic syndrome in an urban Mexican cohort

Background

In the Mexican population metabolic syndrome (MS) is highly prevalent. It is well documented that regular physical activity (PA) prevents coronary diseases, type 2 diabetes and MS. Most studies of PA have focused on moderate-vigorous leisure-time activity, because it involves higher energy expenditures, increase physical fitness, and decrease the risk of MS. However, for most people it is difficult to get a significant amount of PA from only moderately-vigorous leisure activity, so workplace activity may be an option for working populations, because, although may not be as vigorous in terms of cardio-respiratory efforts, it comprises a considerable proportion of the total daily activity with important energy expenditure. Since studies have also documented that different types and intensity of daily PA, including low-intensity, seem to confer important health benefits such as prevent MS, we sought to assess the impact of different amounts of leisure-time and workplace activities, including low-intensity level on MS prevention, in a sample of urban Mexican adults.

Methods

The study population consisted of 5118 employees and their relatives, aged 20 to 70 years, who were enrolled in the baseline evaluation of a cohort study. MS was assessed according to the criteria of the National Cholesterol Education Program, ATP III and physical activity with a validated self-administered questionnaire. Associations between physical activity and MS risk were assessed with multivariate logistic regression models.

Results

The prevalence of the components of MS in the study population were: high glucose levels 14.2%, high triglycerides 40.9%, high blood pressure 20.4%, greater than healthful waist circumference 43.2% and low-high density lipoprotein 76.9%. The prevalence of MS was 24.4%; 25.3% in men and 21.8% in women. MS risk was reduced among men (OR 0.72; 95%CI 0.57–0.95) and women (OR 0.78; 95%CI 0.64–0.94) who reported an amount of ≥30 minutes/day of leisure-time activity, and among women who reported an amount of ≥3 hours/day of workplace activity (OR 0.75; 95%CI 0.59–0.96).

Conclusion

Our results indicate that both leisure-time and workplace activity at different intensity levels, including low-intensity significantly reduce the risk of MS. This finding highlights the need for more recommendations regarding the specific amount and intensity of leisure-time and workplace activity needed to prevent MS.

The association of levels of physical activity with metabolic syndrome in rural Australian adults

Background

Physical activity (PA) reduces risk factors related to metabolic syndrome. Rurality influences the way people incorporate physical activity into daily life. The aim of this study is to determine the association of PA level with metabolic syndrome in a rural Australian population. The influence of adiposity on these associations is also investigated.

Methods

Three cross-sectional population health surveys were conducted in south-east Australia during 2004–2006 using a random population sample (n = 1563, participation rate 49%) aged 25–74 years. PA was assessed via a self-administered questionnaire, and components of the metabolic syndrome via anthropometric measurements taken by specially trained nurses and laboratory tests.

Results

Approximately one-fifth of participants were inactive in leisure-time and over one-third had metabolic syndrome (men 39%, women 33%; p = 0.022). There was an inverse association between level of PA and metabolic syndrome (p < 0.001). Men who were inactive in leisure-time were more than twice as likely and women more than three times as likely to have metabolic syndrome compared with those having high PA. Body mass index (BMI) is a mediating factor in the association between level of PA and metabolic syndrome.

Conclusion

Some PA is better than none if adults, particularly women, are to reduce their risk of metabolic syndrome and associated vascular diseases. Specialised interventions that take rurality into consideration are recommended for adults who are inactive.

Independent and combined influence of physical activity and perceived stress on the metabolic syndrome in male law enforcement officers

OBJECTIVE

: To examine the independent and combined interrelationships among physical activity, perceived stress, and the metabolic syndrome in law enforcement officers (LEOs).

METHODS

: Perceived stress, self-reported physical activity, and metabolic syndrome risk factors were assessed in 386 white male LEOs.

RESULTS

: Among the LEOs, 23.1% had the metabolic syndrome. The metabolic syndrome was not significantly associated with perceived stress (r = 0.047) whereas physical activity was (r = -0.225, P < 0.0001). The odds ratios (95% CI) for possessing the metabolic syndrome in the low and moderate physical activity groups compared to the high physical activity group were 3.13 (95% CI = 1.56 to 6.26) and 2.30 (95% CI = 1.29 to 4.09), respectively.

CONCLUSIONS

: Regardless of stress level, physical inactivity is an important risk factor in the metabolic syndrome among this unique occupational group.

Sports activity and risk of type 2 diabetes in Chinese

An association between physical inactivity and obesity risk has been established. However, the relationship between sports activity and the risk of diabetes among Chinese populations is still unclear. We prospectively investigated the association between sports activity and incidence of type 2 diabetes in a Chinese population. Habitual physical activity in the presumed last year was obtained from a questionnaire developed by Baecke and colleagues. During a median 9.02-year follow-up period among the 1936 participants with complete questionnaire data, 312 participants developed diabetes. After adjusting for age, gender and body mass index, the relative risk (RR) of diabetes according to quartiles of sports activity were 0.86, 0.71 and 0.72 (95% Confidence Interval [CI], 0.52-0.99, P for trend, 0.048). Participants with the highest quartiles of sports activity had a significantly lower risk than the participants with the lowest quartiles among the obese group (multivariate RR, 0.61, 95% CI, 0.41-0.92, P for trend=0.018). Furthermore, the RRs of diabetes were 2.24 (95% CI, 1.58-3.19) for participants who were obese and sedentary, compared with those who were of a healthy weight and participated actively in sports. The findings suggest a significant inverse association between sports activity and incidence of type 2 diabetes in middle to older-aged Chinese individuals.

Associations of physical activity with inflammatory factors, adipocytokines, and metabolic syndrome in middle-aged and older chinese people

BACKGROUND

Inflammatory factors, adipocytokines, and the metabolic syndrome are important determinants of cardiometabolic disease. It remains unclear how physical activity is related to these risk factors. Our objective was to investigate single and joint associations of physical activity with inflammatory factors, adipocytokines, and the metabolic syndrome among middle-aged and older Chinese people.

METHODS AND RESULTS

A total of 3289 individuals (1458 men, 1831 women) 50 to 70 years of age participated in a population-based cross-sectional survey in Beijing and Shanghai, China. Levels of total physical activity were assessed with the International Physical Activity Questionnaire. High-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-alpha receptor 2, adiponectin, and retinol-binding protein 4 were measured. The metabolic syndrome was defined using the updated National Cholesterol Education Program/Adult Treatment Panel III criteria for Asian Americans. Plasma concentrations of high-sensitivity C-reactive protein were 1.58, 1.74, and 1.27 mg/L (P=0.0138) and of adiponectin were 16.12, 16.20, and 17.21 mg/L (P=0.0078) among individuals with low, medium, and high levels of total physical activity, respectively, with adjustment for potential confounders. In the multivariable-adjusted logistic regression analyses, participants with higher levels of total physical activity had a lower risk of having the metabolic syndrome (odds ratio, 0.68; 95% confidence interval, 0.54 to 0.85; P for trend=0.001) compared with those with lower levels.

CONCLUSIONS

Being physically active is associated with a better profile of inflammatory factors and adipocytokines and a reduced risk of having the metabolic syndrome among Chinese people.

Relationship between insulin resistance-associated metabolic parameters and anthropometric measurements with sugar-sweetened beverage intake and physical activity levels in US adolescents: findings from the 1999-2004 National Health and Nutrition Examination Survey

OBJECTIVE

To evaluate the relationship between insulin resistance-associated metabolic parameters and anthropometric measurements with sugar-sweetened beverage intake and physical activity levels.

DESIGN

A cross-sectional analysis of the National Health and Nutrition Examination Survey data collected by the National Center for Health Statistics.

SETTING

Nationally representative samples of US adolescents participating in the National Health and Nutrition Examination Survey during the years 1999-2004.

PARTICIPANTS

A total of 6967 adolescents aged 12 to 19 years.

MAIN EXPOSURE

Sugar-sweetened beverage consumption and physical activity levels.

OUTCOME MEASURES

Glucose and insulin concentrations, a homeostasis model assessment of insulin resistance (HOMA-IR), total, high-density lipoprotein, and low-density lipoprotein cholesterol concentrations, triglyceride concentrations, systolic and diastolic blood pressure, waist circumference, and body mass index (calculated as weight in kilograms divided by height in meters squared) percentile for age and sex.

RESULTS

Multivariate linear regression analyses showed that increased sugar-sweetened beverage intake was independently associated with increased HOMA-IR, systolic blood pressure, waist circumference, and body mass index percentile for age and sex and decreased HDL cholesterol concentrations; alternatively, increased physical activity levels were independently associated with decreased HOMA-IR, low-density lipoprotein cholesterol concentrations, and triglyceride concentrations and increased high-density lipoprotein cholesterol concentrations. Furthermore, low sugar-sweetened beverage intake and high physical activity levels appear to modify each others' effects of decreasing HOMA-IR and triglyceride concentrations and increasing high-density lipoprotein cholesterol concentrations.

CONCLUSIONS

Sugar-sweetened beverage intake and physical activity levels are each independently associated with insulin resistance-associated metabolic parameters and anthropometric measurements in adolescents. Moreover, low sugar-sweetened beverage intake and high physical activity levels appear to modify each others' effects on several health-related outcome variables.

Physical activity and the metabolic syndrome in elderly German men and women: results from the population-based KORA survey

OBJECTIVE

The purpose of this study is to determine the optimal duration and intensity of exercise for elderly people for the prevention of the metabolic syndrome.

RESEARCH DESIGN AND METHODS

The population-based Cooperative Research in the Region of Augsburg (KORA) S4 Survey with 1,653 participants aged 55-74 years was used to investigate the relationship between the metabolic syndrome and physical activity.

RESULTS

Fifty-seven percent of men and 48% of women showed clinical symptoms of the metabolic syndrome. Leisure activities were common (>80% walked >30 min/day). Sports activities performed regularly for <or=1 h per week reduced the odds of having the metabolic syndrome (odds ratio 0.70 [95% CI 0.49-1.02] for men and 0.74 [0.53-1.04] for women), and sports activities >2 h per week were even more effective (0.62 [0.42-0.92] for men and 0.59 [0.39-0.89] for women). In contrast, activities such as walking and cycling did not have an additional influence.

CONCLUSIONS

Intense physical activity by the elderly should be promoted in addition to leisure physical activity for the prevention of the metabolic syndrome.

Metabolic syndrome and physical activity in southern Brazilian community-dwelling elders: a population-based, cross-sectional study

BACKGROUND

The association between a sedentary lifestyle and obesity is well documented, and is linked to an increased prevalence of metabolic syndrome (MS). There is some evidence that information regarding the health benefits of physical activity is beginning to impact on the elderly people and is beginning to change their behavior. We aimed to investigate the level of physical activity undertaken by elderly people with MS and those without this condition.

METHODS

We evaluated 362 community-dwelling elders of Novo Hamburgo, southern Brazil. Diagnosis of MS was based on the International Diabetes Federation criteria and the physical activity (PA) level was estimated by the International Physical Activity Questionnaire. Analysis of covariance was carried out to verify associations between MS risk factors and the level of PA. Logistic regression was used to estimate the MS odds ratio for each level of PA.

RESULTS

No significant association was found between MS and the level of physical activity, irrespective of sex. The odds ratio for the presence of MS adjusted for sex and age and using insufficiently active elderly people as reference was 1.04 (95% CI, 0.6 to 1.7) in sufficiently active elderly people and 1.15 (95% CI, 0.7 to 2.0) in very active elderly people.

CONCLUSION

The elderly citizens of a southern Brazilian community who were diagnosed with MS presented the same levels of PA as the individuals who did not have this diagnosis. This may imply that information on the importance of physical activity has already reached this higher risk population.

Central adiposity and associated lifestyle factors in Cree children

Aboriginal children are prone to central adiposity (CA), a component of the metabolic syndrome. The objective of this study was to determine if lifestyle factors were associated with CA in Canadian Cree children. Children aged 9-12 years were classified as having CA if their waist circumference met or exceeded the 85th percentile of the NHANES III reference. Weight status was determined using the CDC growth reference, dietary intake using three 24 h dietary recalls, physical activity using pedometers, and fitness by completion of the 20 m shuttle run test. Of the 178 children (79% participation rate), 32.6% were normal weight, 23.6% were overweight, and 43.8% were obese. Half (52.2%) of the children had CA (97.4% of obese children, 35.7% of overweight children, and 2.2% of normal weight children). Waist circumference was negatively correlated with pedometer step counts (r = -0.187, p = 0.012) and shuttle run time (r = -0.508, p < 0.001). In children with CA, waist circumference was positively correlated with sweetened beverage intake (r = 0.250, p = 0.016). The odds ratio (adjusted for age and sex) for CA for children consuming 3 or more fruits and vegetables per day was 0.43 (95% CI 0.18 - 0.98), for meeting step recommendations for a healthy body weight was 0.45 (95% CI 0.24 - 0.84), and for relative fitness was 0.12 (95% CI 0.04 - 0.33). CA was prevalent in children who were overweight and obese. Preventive strategies might include promoting a healthy diet, physical activity, and fitness.

Biological and behavioural explanations of social inequalities in coronary heart disease: the Whitehall II study

AIMS/HYPOTHESIS

We determined the degree to which metabolic syndrome components, inflammation and health behaviours account for the social gradient in CHD.

METHODS

A total of 5312 men, initially aged 39 to 63 years, were followed for 13.1 years for incident coronary death or non-fatal myocardial infarction according to socioeconomic position (employment grade). The contribution of explanatory factors to socioeconomic differences in CHD was assessed by the reduction in hazard ratios computed using Cox models. The effects of measurement error were taken into account.

RESULTS

Coronary events were more common in lower employment grades than in higher, with a hazard ratio (relative index of inequality) of 2.2 (95% CI 1.3-3.7), after adjustment for age and ethnic group. Behavioural risk factors (mainly smoking and diet) explained a third of the socioeconomic gradient in CHD incidence. Components of the metabolic syndrome and inflammatory markers predicted CHD incidence and also explained a third of the gradient. Combined, these two groups of predictors, i.e. behavioural and biological, accounted for over half of the socioeconomic gradient in incident CHD. Adding body height as a marker of the effects of early life increased this figure to about 60%.

CONCLUSIONS/INTERPRETATION

A major question has been how someone's socioeconomic position can lead to increased risk of CHD. Socioeconomic differences in components of the metabolic syndrome (and inflammatory markers) provide part of the answer. This was, to an important degree, independent of the contribution of health behaviours to the socioeconomic differentials in CHD.

Objective measures of neighborhood environment and self-reported physical activity in spinal cord injured men

OBJECTIVES

To assess the relationship between objective neighborhood environment and self-reported physical activity (PA) and between PA and obesity-related risk factors in people with spinal cord injury (SCI).

DESIGN

A cross-sectional study.

SETTING

Urban university.

PARTICIPANTS

Men with SCI (N=131), 20 to 59 years old, at least 1 year postinjury and using wheelchair for mobility most of the time.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Metabolic syndrome (abdominal obesity, elevated blood pressure, glucose, triglycerides, and low-high density lipoprotein cholesterol) and high C-reactive protein (CRP), as well as total PA metabolic equivalent score.

RESULTS

Lower PA was associated with higher prevalence rate for elevated triglycerides, metabolic syndrome, and high CRP. Compared with those in low PA tertile, those in high PA tertile had significantly lower odds for elevated triglycerides (odds ratio [OR]=.19; 95% confidence interval [CI], .04-.80), metabolic syndrome (OR=.15; 95% CI, .03-.66) and high CRP (OR=.17; 95% CI, .04-.71) while adjusting for relevant factors. In crude analysis, lower PA was associated with neighborhood environmental characteristics including shorter distance to nearest transit stops, smaller mean block area, greater number of transit stops, high vacant housing, and higher neighborhood crime rate. In multivariate analysis higher total crime was the only risk factor significantly associated with lower PA level. Those living in higher crime rate neighborhoods had 86% lower odds of having greater than median PA level (OR=.14; 95% CI, .04-.49) than their counterparts.

CONCLUSIONS

In men with SCI, lower PA is independently associated with having elevated triglycerides, metabolic syndrome, and high CRP. Additionally, lower PA is associated with higher neighborhood crime rate.

Association between television viewing and the risk of metabolic syndrome in a community-based population

BACKGROUND

As a result of metabolic syndrome becoming an important issue during recent decades, many studies have explored the risk factors contributing to its development. However, less attention has been paid to the risk associated with sedentary behavior, especially television viewing. This study examined the association between television viewing time and the risk of having metabolic syndrome in a population of Taiwanese subjects.

METHODS

This community-based cross-sectional study included 2,353 subjects (1,144 men and 1,209 women) aged 40 and over from October, 2004 to September, 2005. Information about the time spent watching TV was obtained using a self-administered questionnaire. The definition of metabolic syndrome was according to the Third Report of the National Cholesterol Education Program's Adult Treatment Panel modified for Asians.

RESULTS

Compared to subjects who viewed TV < 14 hr/week, those who viewed TV > 20 hr/week had a 1.50-fold (95% confidence intervals (CI): 1.10, 2.03) risk for men and a 1.93-fold (95% CI: 1.37, 2.71) risk for women of having metabolic syndrome, after adjusting for physical activity and other covariates. Stratifying by the three categories of total activity levels, TV viewing time > 20 hr/week was found to still hold a significant risk for having metabolic syndrome in the lowest of the three categories of total activity level for men and in all three categories of total activity level for women.

CONCLUSION

The findings suggest that TV viewing is an independent risk factor associated with metabolic syndrome in Taiwanese people.

Fatores de risco para síndrome metabólica em cadeirantes: jogadores de basquetebol e não praticantes

A atividade física tem sido sistematicamente estudada como fator preventivo no acometimento de enfermidades crônico-degenerativas, especialmente a síndrome metabólica e doenças cardiovasculares. Sedentarismo está relacionado à diminuição ou ausência de parâmetros mínimos de exigência física diária além do estado de repouso, sendo este fortemente associado à redução na condição de saúde dos indivíduos portadores de deficiência física. As respostas metabólicas do organismo mediante a ausência de determinada musculatura, ou sua inatividade pela falta de estímulos, conduzem a diferenças significativas na estruturação da composição corporal. Esta pesquisa teve como objeto o exercício físico regular e a condição de saúde de indivíduos portadores de deficiência física, através da determinação do perfil antropométrico e bioquímico sangüíneo, e ainda pela determinação da prevalência de fatores de risco para síndrome metabólica. Foram estudados 27 homens com paraplegia (T2-L1), portadores de seqüelas de poliomielite ou amputados, divididos em jogadores de basquetebol cadeirantes (JBC) e não jogadores de basquetebol cadeirantes (NJBC). Os JBC apresentaram circunferência de cintura menor comparada aos NJBC, 76,40±8,44 e 89,25±9,73 cm respectivamente (p<0,05). A pressão arterial sistólica foi significativamente maior nos NJBC 123,33±13,70 e 114,00±9,85 mmHg para JBC (p<0,05), não sendo verificada diferença para PAD. Os NJBC apresentaram valores superiores aos JBC para a bioquímica sangüínea de glicemia, TG, CT e frações, exceto para HDL-C (p<0,05). Os indivíduos NJBC apresentaram alta prevalência para fatores de risco da SM, sendo hipertensão arterial prevalente em 58,33% dos indivíduos, dislipidemia de HDL-C presente em 50% e circunferência de cintura acima da normalidade em 41,66%. Os achados do presente estudo sugerem um papel importante do exercício físico na prevenção da síndrome metabólica, embora estudos adicionais devam ser realizados para a melhor compreensão dos mecanismos que promovem a saúde dos deficientes físicos ativos.

Increasing overall physical activity and aerobic fitness is associated with improvements in metabolic risk: cohort analysis of the ProActive trial

AIMS/HYPOTHESIS

Our aim was to examine the association between change in physical activity energy expenditure (PAEE), total body movement (counts per day) and aerobic fitness (maximum oxygen consumption [VO2max] over 1 year and metabolic risk among individuals with a family history of diabetes.

METHODS

Three hundred and sixty-five offspring of people with type 2 diabetes underwent measurement of energy expenditure (PAEE measured using the flex heart rate method), total body movement (daily activity counts from accelerometry data), [VO2max] predicted from a submaximal graded treadmill exercise test and anthropometric and metabolic status at baseline and 1 year (n = 321) in the ProActive trial. Clustered metabolic risk was calculated by summing standardised values for waist circumference, fasting triacylglycerol, insulin and glucose, blood pressure and the inverse of HDL-cholesterol. Linear regression was used to quantify the association between changes in PAEE, total body movement and fitness and clustered metabolic risk at follow-up.

RESULTS

Participants increased their activity by 0.01 units PAEE kJ kg(-1) day(-1) over 1 year. Total body movement increased by an average of 9,848 counts per day. Change in total body movement (beta = -0.066, p = 0.004) and fitness (beta = -0.056, p = 0.003) was associated with clustered metabolic risk at follow-up, independently of age, sex, smoking status, socioeconomic status and baseline metabolic score.

CONCLUSIONS/INTERPRETATION

Small increases in activity and fitness were associated with a reduction in clustered metabolic risk in this cohort of carefully characterised at-risk individuals. Further research to quantify the reduction in risk of type 2 diabetes associated with feasible changes in these variables should inform preventive interventions.

Adolescents with metabolic syndrome have a history of low aerobic fitness and physical activity levels

Purpose

Metabolic syndrome (MS) is a clustering of cardiovascular disease risk factors that identifies individuals with the highest risk for heart disease. Two factors that may influence the MS are physical activity and aerobic fitness. This study determined if adolescent with the MS had low levels of aerobic fitness and physical activity as children.

Methods

This longitudinal, exploratory study had 389 participants: 51% girls, 84% Caucasian, 12% African American, 1% Hispanic, and 3% other races, from the State of North Carolina. Habitual physical activity (PA survey), aerobic fitness (VO₂max), body mass index (BMI), blood pressure, and lipids obtained at 7–10 y of age were compared to their results obtained 7 y later at ages 14–17 y.

Results

Eighteen adolescents (4.6%) developed 3 or more characteristics of the MS. Logistic regression, adjusting for BMI percentile, blood pressure, and cholesterol levels, found that adolescents with the MS were 6.08 (95%CI = 1.18–60.08) times more likely to have low aerobic fitness as children and 5.16 (95%CI = 1.06–49.66) times more likely to have low PA levels.

Conclusion

Low levels of childhood physical activity and aerobic fitness are associated with the presence of the metabolic syndrome in adolescents. Thus, efforts need to begin early in childhood to increase exercise.

Walking, vigorous physical activity, and markers of hemostasis and inflammation in healthy men and women

The impact of walking on cardiovascular health, as compared with vigorous physical activity, remains controversial. We performed a cross-sectional analysis including 185 healthy participants drawn from the Whitehall II epidemiological cohort to examine whether there is an independent association between walking and markers of hemostasis and inflammation after controlling for vigorous physical activity. Blood was drawn for the assessment of von Willebrand factor antigen (vWF), fibrinogen, interleukin (IL)-6, IL-1 receptor antagonist (IL-1ra), and tumor necrosis factor-alpha (TNF-alpha). Self-reported levels and types of physical activity were recorded, including time spent walking per week and frequency of participation in vigorous physical activity. Multiple linear regression analyses, adjusted for age, body mass index, blood pressure, gender, smoking, alcohol, grade of employment, and frequency of vigorous physical activity revealed that time spent walking was inversely related to vWF (beta=-0.13, P=0.086), fibrinogen (beta=-0.16, P=0.016), IL-6 (beta=-0.12, P=0.087), and TNF-alpha (beta=-0.16, P=0.039). In addition, vigorous activity was inversely associated with hemostatic markers but not with inflammatory cytokines. Regular walking is associated with lower levels of hemostatic and inflammatory markers independently of vigorous physical activity in healthy men and women.

Unfairness and the social gradient of metabolic syndrome in the Whitehall II Study

OBJECTIVES

Little work has investigated the relationship between unfairness and risk factors for heart disease. We examine the role of unfairness in predicting the metabolic syndrome and explaining the social gradient of the metabolic syndrome.

METHODS

The design is a prospective study with an average follow-up of 5.8 years. Participants were 4128 males and 1715 females of 20 civil service departments in London (Whitehall II study). Sociodemographics, unfairness, employment grade, behavioral risk factors, and other psychosocial factors were measured at baseline (Phase 3, 1991-1993). Waist circumference, triglycerides, high-density lipoprotein (HDL) cholesterol, fasting glucose, and hypertension were used to define metabolic syndrome at follow-up (Phase 5, 1997-2000), according to the National Cholesterol Education Program/Adult Treatment Panel III guidelines.

RESULTS

Unfairness is positively associated with waist circumference, hypertension, triglycerides, and fasting glucose and negatively associated with serum HDL cholesterol. High levels of unfairness are also associated with the metabolic syndrome [odds ratio (OR)=1.72, 95% CI=1.31-2.25], after adjustment for age and gender. After additional adjustment for employment grade, behavioral risk factors, and other psychosocial factors, the relationship between high unfairness and metabolic syndrome weakened but remained significant (OR=1.37, 95% CI=1.00-1.93). When adjusting for unfairness, the social gradient of metabolic syndrome was reduced by approximately 10%.

CONCLUSION

Unfairness may be a risk factor for the metabolic syndrome and its components. Future research is needed to study the biological mechanisms linking unfairness and the metabolic syndrome.

Leisure time physical activity in middle age predicts the metabolic syndrome in old age: results of a 28-year follow-up of men in the Oslo study

Background

Data are scarce on the long term relationship between leisure time physical activity, smoking and development of metabolic syndrome and diabetes. We wanted to investigate the relationship between leisure time physical activity and smoking measured in middle age and the occurrence of the metabolic syndrome and diabetes in men that participated in two cardiovascular screenings of the Oslo Study 28 years apart.

Methods

Men residing in Oslo and born in 1923–32 (n = 16 209) were screened for cardiovascular diseases and risk factors in 1972/3. Of the original cohort, those who also lived in same area in 2000 were invited to a repeat screening examination, attended by 6 410 men. The metabolic syndrome was defined according to a modification of the National Cholesterol Education Program criteria. Leisure time physical activity, smoking, educational attendance and the presence of diabetes were self-reported.

Results

Leisure time physical activity decreased between the first and second screening and tracked only moderately between the two time points (Spearman's ρ = 0.25). Leisure time physical activity adjusted for age and educational attendance was a significant predictor of both the metabolic syndrome and diabetes in 2000 (odds ratio for moderately vigorous versus sedentary/light activity was 0.65 [95% CI, 0.54–0.80] for the metabolic syndrome and 0.68 [0.52–0.91] for diabetes) (test for trend P < 0.05). However, when adjusted for more factors measured in 1972/3 including glucose, triglycerides, body mass index, treated hypertension and systolic blood pressure these associations were markedly attenuated. Smoking was associated with the metabolic syndrome but not with diabetes in 2000.

Conclusion

Physical activity during leisure recorded in middle age prior to the current waves of obesity and diabetes had an independent predictive association with the presence of the metabolic syndrome but not significantly so with diabetes 28 years later in life, when the subjects were elderly.

Metabolic syndrome: psychosocial, neuroendocrine, and classical risk factors in type 2 diabetes

This article summarizes some aspects of stress in the metabolic syndrome at the psychosocial, tissue, and cellular levels. The metabolic syndrome is a valuable research concept for studying population health and social-biological translation. The cluster of cardiovascular risk factors labeled the metabolic syndrome is linked with low socioeconomic status. Systematic differences in diet and physical activity contribute to social patterning of the syndrome. In addition, psychosocial factors including chronic work stress are linked with its development. Psychosocial factors could lead to metabolic perturbations and increase cardiovascular risk via activation of neuroendocrine responses, for example, in the autonomic nervous system and in several hormonal pathways. High glucocorticoid levels will promote lipid storage in visceral rather than subcutaneous adipose tissue. Adipocytes secrete several proinflammatory cytokines, which considered major contributors to increase in oxidants and cell injury. Upregulation of heme oxygenase 1 (HO-1) and peroxidase in the early development of diabetes produces a decrease in oxidative-mediated injury. Increased HO activity is associated with a significant decrease in superoxide, endothelial cell shedding and blood pressure. Finally, it is proposed that overexpression of glutathione peroxidase in beta cells may protect beta cell deterioration from oxidative stress during development of diabetes and hyperglycemia and this may result in attenuation of beta cell failure. If this proves to be the case, then the scene will be set to develop glutathione peroxidase mimetics for use in preclinical and clinical trials.

Physical activity in prevention and treatment of the metabolic syndrome

Randomised controlled trials have shown that exercise training has a mild or moderate favourable effect on many metabolic and cardiovascular risk factors that constitute or are related to the metabolic syndrome (MetS). Epidemiological studies suggest that regular physical activity prevents type 2 diabetes, cardiovascular disease, and premature mortality in large part through these risk factors. Although randomized controlled trials with the prevention or treatment of the MetS as the main outcome have not been published, several large randomized controlled trials provide strong evidence that favourable lifestyle changes, including regular physical activity, are effective in the prevention of type 2 diabetes in individuals who are overweight and have impaired glucose tolerance. Compliance with the current recommendations to increase the total volume of moderate-intensity physical activity and to maintain good cardiorespiratory and muscular fitness appears to markedly decrease the likelihood of developing the MetS, especially in high-risk groups. Walking is the most common form of physical activity--it improves health in many ways and is generally safe. Therefore, brisk walking for at least 30 min daily can be recommended as the principal form of physical activity at the population level. If there are no contraindications, more vigorous physical exercise or resistance training should also be considered to obtain additional health benefits. Unstructured and low-intensity physical activity may also decrease the likelihood of developing the MetS, especially when substituted for sedentary behaviours such as watching television. The measurement of maximal oxygen consumption may provide an efficient means to target even individuals with relatively few metabolic risk factors who may benefit from more intensive intervention.