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

An Interdisciplinary Intervention Based on Prescription of Physical Activity, Diet, and Positive Mental Health to Promote Healthy Lifestyle in Patients with Obesity: A Randomized Control Trial

This study used a multimodal approach to address the issue of obesity among individuals with a Body Mass Index (BMI) between 30 and 40 residing in a rural region of north-east Spain. A pretest-posttest model was employed in a clinical trial design, comparing an intervention group with a control group. The intervention, which lasted for a period of nine months, was based on three main strategies: the prescription of physical activity, the promotion of healthy nutritional habits, and the management of emotional wellbeing through Positive Mental Health (PMH). A variety of assessment tools were employed, including the CLASS-AF scale and a stress test for physical activity levels; advanced anthropometry and blood analysis for metabolic and body composition variables; a Mediterranean diet adherence questionnaire for nutritional habits; and a PMH multifactorial questionnaire for the assessment of emotional management. The results revealed significant improvements in the level of physical activity and adherence to the Mediterranean diet in favor of the intervention group, where 89.4% (n = 17) of the participants went from being not very active/sedentary to being active. Also, adherence to the Mediterranean diet improved with a mean increase of 2.2 points on the scale [mean: 10.5 (CI 95%: 9.90, 11.09)]. In addition, significant reductions in body fat [mean: -2.50 kg (CI 95%: -3.56, -1.44)] and free fat mass [mean: -3.38% (IC 95%: -4.34, -2.41), along with decreased cholesterol levels (196 vs. 182 mg/dL), were observed, suggesting a decrease in cardiovascular and metabolic risk. In conclusion, this multimodal intervention was effective at improving the lifestyle of people with obesity and reducing their cardiovascular and metabolic risk. The combination of interventions focused on physical activity, diet, Positive Mental Health, and metabolic changes and were perceived as a comprehensive and complementary strategy in obesity care. These findings highlight the importance of approaching this condition from multiple perspectives to ensure optimal health outcomes.

Role of Cardiorespiratory Fitness and Mitochondrial Oxidative Capacity in Reduced Walk Speed of Older Adults With Diabetes

Cardiorespiratory fitness and mitochondrial oxidative capacity are associated with reduced walking speed in older adults, but their impact on walking speed in older adults with diabetes has not been clearly defined. We examined differences in cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity between older adults with and without diabetes, as well as determined their relative contribution to slower walking speed in older adults with diabetes. Participants with diabetes (n = 159) had lower cardiorespiratory fitness and mitochondrial respiration in permeabilized fiber bundles compared with those without diabetes (n = 717), following adjustments for covariates including BMI, chronic comorbid health conditions, and physical activity. Four-meter and 400-m walking speeds were slower in those with diabetes. Mitochondrial oxidative capacity alone or combined with cardiorespiratory fitness mediated ∼20-70% of the difference in walking speed between older adults with and without diabetes. Additional adjustments for BMI and comorbidities further explained the group differences in walking speed. Cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity contribute to slower walking speeds in older adults with diabetes.

ARTICLE HIGHLIGHTS

Parental cardiorespiratory fitness influences early life energetics and metabolic health

High cardiorespiratory fitness (CRF) is associated with a reduced risk of metabolic disease and is linked to superior mitochondrial respiratory function. This study investigated how intrinsic CRF affects bioenergetics and metabolic health in adulthood and early life. Adult rats selectively bred for low and high running capacity [low capacity runners (LCR) and high capacity runners (HCR), respectively] underwent metabolic phenotyping before mating. Weanlings were evaluated at 4-6 wk of age, and whole body energetics and behavior were assessed using metabolic cages. Mitochondrial respiratory function was assessed in permeabilized tissues through high-resolution respirometry. Proteomic signatures of adult and weanling tissues were determined using mass spectrometry. The adult HCR group exhibited lower body mass, improved glucose tolerance, and greater physical activity compared with the LCR group. The adult HCR group demonstrated higher mitochondrial respiratory capacities in the soleus and heart compared with the adult LCR group, which coincided with a greater abundance of proteins involved in lipid catabolism. HCR and LCR weanlings had similar body mass, but HCR weanlings displayed reduced adiposity. In addition, HCR weanlings exhibited better glucose tolerance and higher physical activity levels than LCR weanlings. Higher respiratory capacities were observed in the soleus, heart, and liver tissues of HCR weanlings compared with LCR weanlings, which were not owed to greater mitochondrial content. Proteomic analyses indicated a greater potential for lipid oxidation in the contractile muscles of HCR weanlings. In conclusion, offspring born to parents with high CRF possess an enhanced capacity for lipid catabolism and oxidative phosphorylation, thereby influencing metabolic health. These findings highlight that intrinsic CRF shapes the bioenergetic phenotype with implications for metabolic resilience in early life.NEW & NOTEWORTHY Inherited cardiorespiratory fitness (CRF) influences early life bioenergetics and metabolic health. Higher intrinsic CRF was associated with reduced adiposity and improved glucose tolerance in early life. This metabolic phenotype was accompanied by greater mitochondrial respiratory capacity in skeletal muscle, heart, and liver tissue. Proteomic profiling of these three tissues further revealed potential mechanisms linking inherited CRF to early life metabolism.

Independent and joint associations of cardiorespiratory fitness and BMI with dementia risk: the Cooper Center Longitudinal Study

OBJECTIVE

This study aimed to examine the association of midlife fitness and body mass index (BMI) with incident dementia later in life.

DESIGN AND PARTICIPANTS

A cohort study of 6428 individuals (mean age 50.9±7.6 years) from the Cooper Center Longitudinal Study.

MEASURES

Cardiorespiratory fitness and BMI were assessed twice (1970-1999) during visits to the Cooper Clinic, a preventive medicine clinic in Dallas, Texas. These measures were examined as continuous and categorical variables. As continuous variables, fitness and BMI were examined at baseline (averaged of two examinations) and as absolute change between exams (mean time 2.1±1.8 years). Variables were categorised: unfit versus fit and normal versus overweight/obese. Medicare claims data were used to obtain all-cause dementia incidence (1999-2009). Mean follow-up between midlife examinations and Medicare surveillance was 15.7 ((SD=6.2) years. Multivariable models were used to assess the associations between fitness, BMI and dementia.

RESULTS

During 40 773 person years of Medicare surveillance, 632 cases of dementia were identified. After controlling for BMI and covariates, each 1-metabolic equivalent increment in fitness was associated with 5% lower (HR 0.95; 95% CI 0.90 to 0.99) dementia risk. In comparison, after controlling for fitness and covariates, each 1 kg/m2 increment in BMI was associated with a 3.0% (HR 1.03; 95% CI 1.00 to 1.07) higher risk for dementia, yet without significance (p=0.051). Similar findings were observed when the exposures were categorised. Changes in fitness and BMI between examinations were not related to dementia. Jointly, participants who were unfit and overweight/obese had the highest (HR 2.28 95% CI 1.57 to 3.32) dementia risk compared with their fit and normal weight counterparts.

CONCLUSION

Lower midlife fitness is a risk marker for dementia irrespective of weight status. Being unfit coupled with overweight/obese status might increase one's risk for dementia even further.

Role of Cardiorespiratory Fitness and Mitochondrial Energetics in Reduced Walk Speed of Older Adults with Diabetes in the Study of Muscle, Mobility and Aging (SOMMA)

Rationale

Cardiorespiratory fitness and mitochondrial energetics are associated with reduced walking speed in older adults. The impact of cardiorespiratory fitness and mitochondrial energetics on walking speed in older adults with diabetes has not been clearly defined.

Objective

To examine differences in cardiorespiratory fitness and skeletal muscle mitochondrial energetics between older adults with and without diabetes. We also assessed the contribution of cardiorespiratory fitness and skeletal muscle mitochondrial energetics to slower walking speed in older adults with diabetes.

Findings

Participants with diabetes had lower cardiorespiratory fitness and mitochondrial energetics when compared to those without diabetes, following adjustments for covariates including BMI, chronic comorbid health conditions, and physical activity. 4-m and 400-m walking speeds were slower in those with diabetes. Mitochondrial oxidative capacity alone or combined with cardiorespiratory fitness mediated ∼20-70% of the difference in walk speed between older adults with and without diabetes. Further adjustments of BMI and co-morbidities further explained the group differences in walk speed.

Conclusions

Skeletal muscle mitochondrial energetics and cardiorespiratory fitness contribute to slower walking speeds in older adults with diabetes. Cardiorespiratory fitness and mitochondrial energetics may be therapeutic targets to maintain or improve mobility in older adults with diabetes.

ARTICLE HIGHLIGHTS

Why did we undertake this study? To determine if mitochondrial energetics and cardiorespiratory fitness contribute to slower walking speed in older adults with diabetes. What is the specific question(s) we wanted to answer? Are mitochondrial energetics and cardiorespiratory fitness in older adults with diabetes lower than those without diabetes? How does mitochondrial energetics and cardiorespiratory fitness impact walking speed in older adults with diabetes? What did we find? Mitochondrial energetics and cardiorespiratory fitness were lower in older adults with diabetes compared to those without diabetes, and energetics, and cardiorespiratory fitness, contributed to slower walking speed in those with diabetes. What are the implications of our findings? Cardiorespiratory fitness and mitochondrial energetics may be key therapeutic targets to maintain or improve mobility in older adults with diabetes.

Association between estimated cardiorespiratory fitness and breast cancer: a prospective cohort study

OBJECTIVE

To examine the association between cardiorespiratory fitness (CRF) and the risk of breast cancer in postmenopausal women.

METHODS

This study used data from 17 840 cancer-free postmenopausal women with a CRF assessment from the UK Biobank. High estimated CRF (eCRF) was categorised as being >80th percentile within 10-year age bands. Fine and Gray regression was used to examine the association between eCRF and breast cancer risk, accounting for both non-breast cancer diagnoses and all-cause mortality as competing risks. Age was used as the time scale. Several different models were produced, including those adjusting for known breast cancer risk factors, and stratified by measures of body fat (body mass index and per cent body fat).

RESULTS

Over a median follow-up of 11.0 years there were 529 cases of invasive breast cancer, 1623 cases of non-breast cancer disease and 241 deaths. With adjustment for breast cancer risk factors, high eCRF was associated with a 24% (subdistribution HR (SDHR) 0.76, 95% CI 0.60 to 0.97) lower risk of breast cancer. When stratified by measures of body fat, we found evidence of effect measure modification. Mainly, having high eCRF was only associated with a lower risk of breast cancer among those classified as having overweight/obesity (SDHR 0.33, 95% CI 0.11 to 1.01) or percentage body fat above the 1st quintile (SDHR 0.65, 95% CI 0.45 to 0.94).

CONCLUSION

Having higher CRF may be a protective factor against breast cancer in postmenopausal women but only for women with elevated body fat.

Nonexercise machine learning models for maximal oxygen uptake prediction in national population surveys

OBJECTIVE

Nonexercise algorithms are cost-effective methods to estimate cardiorespiratory fitness (CRF), but the existing models have limitations in generalizability and predictive power. This study aims to improve the nonexercise algorithms using machine learning (ML) methods and data from US national population surveys.

MATERIALS AND METHODS

We used the 1999-2004 data from the National Health and Nutrition Examination Survey (NHANES). Maximal oxygen uptake (VO2 max), measured through a submaximal exercise test, served as the gold standard measure for CRF in this study. We applied multiple ML algorithms to build 2 models: a parsimonious model using commonly available interview and examination data, and an extended model additionally incorporating variables from Dual-Energy X-ray Absorptiometry (DEXA) and standard laboratory tests in clinical practice. Key predictors were identified using Shapley additive explanation (SHAP).

RESULTS

Among the 5668 NHANES participants in the study population, 49.9% were women and the mean (SD) age was 32.5 years (10.0). The light gradient boosting machine (LightGBM) had the best performance across multiple types of supervised ML algorithms. Compared with the best existing nonexercise algorithms that could be applied to the NHANES, the parsimonious LightGBM model (RMSE: 8.51 ml/kg/min [95% CI: 7.73-9.33]) and the extended LightGBM model (RMSE: 8.26 ml/kg/min [95% CI: 7.44-9.09]) significantly reduced the error by 15% and 12% (P < .001 for both), respectively.

DISCUSSION

The integration of ML and national data source presents a novel approach for estimating cardiovascular fitness. This method provides valuable insights for cardiovascular disease risk classification and clinical decision-making, ultimately leading to improved health outcomes.

CONCLUSION

Our nonexercise models provide improved accuracy in estimating VO2 max within NHANES data as compared to existing nonexercise algorithms.

Association between Estimated Cardiorespiratory Fitness and Abnormal Glucose Risk: A Cohort Study

BACKGROUND

Cardiorespiratory fitness (CRF) is a predictor of chronic disease that is impractical to routinely measure in primary care settings. We used a new estimated cardiorespiratory fitness (eCRF) algorithm that uses information routinely documented in electronic health care records to predict abnormal blood glucose incidence.

METHODS

Participants were adults (17.8% female) 20-81 years old at baseline from the Aerobics Center Longitudinal Study between 1979 and 2006. eCRF was based on sex, age, body mass index, resting heart rate, resting blood pressure, and smoking status. CRF was measured by maximal treadmill testing. Cox proportional hazards regression models were established using eCRF and CRF as independent variables predicting the abnormal blood glucose incidence while adjusting for covariates (age, sex, exam year, waist girth, heavy drinking, smoking, and family history of diabetes mellitus and lipids).

RESULTS

Of 8602 participants at risk at baseline, 3580 (41.6%) developed abnormal blood glucose during an average of 4.9 years follow-up. The average eCRF of 12.03 ± 1.75 METs was equivalent to the CRF of 12.15 ± 2.40 METs within the 10% equivalence limit. In fully adjusted models, the estimated risks were the same (HRs = 0.96), eCRF (95% CIs = 0.93-0.99), and CRF (95% CI of 0.94-0.98). Each 1-MET increase was associated with a 4% reduced risk.

CONCLUSIONS

Higher eCRF is associated with a lower risk of abnormal glucose. eCRF can be a vital sign used for research and prevention.

Descriptive Epidemiology of Cardiorespiratory Fitness in UK Adults: The Fenland Study

INTRODUCTION

Cardiorespiratory fitness (CRF) is rarely measured in population studies. Most studies of CRF do not examine differences by population subgroups or seasonal trends. We examined how estimated CRF levels vary by anthropometric, sociodemographic, and behavioral characteristics in a population-based cohort of UK adults (the Fenland Study).

METHODS

We used a validated submaximal exercise test to obtain CRF estimates (CRF estimated ) in 5976 women and 5316 men, residing in the East of England. CRF estimated was defined as estimated maximal oxygen consumption per kilogram total body mass (V̇O 2 max tbm ) and fat-free mass (V̇O 2 max ffm ). Descriptive statistics were computed across anthropometric and sociodemographic characteristics, and across the year. Progressive multivariable analyses were performed to examine associations with physical activity energy expenditure (PAEE) and body mass index (BMI).

RESULTS

Mean ± SD V̇O 2 max tbm was lower in women (35.2 ± 7.5 mL·min -1 ·kg -1 ) than men (41.7 ± 7.3 mL·min -1 ·kg -1 ) but V̇O 2 max ffm was similar (women: 59.2 ± 11.6 mL·min -1 ·kg -1 ; men: 62.0 ± 10.3 mL·min -1 ·kg -1 ). CRF estimated was inversely associated with age but not after adjustment for PAEE. People in more physically demanding jobs were fitter compared with those in sedentary jobs, but this association was attenuated in women and reversed in men after adjustment for total PAEE. Physical activity energy expenditure and BMI were positively associated with CRF estimated at all levels of adjustment when expressed relative to fat-free mass. CRF estimated was 4% higher in summer than in winter among women, but did not differ by season among men.

CONCLUSIONS

CRF estimated was inversely associated with age but less steeply than anticipated, suggesting older generations are comparatively fitter than younger generations. Physical activity energy expenditure and BMI were stronger determinants of the variance in CRF estimated than other characteristic including age. This emphasizes the importance of modifiable physical activity behaviors in public health interventions.

Epidemiological, mechanistic, and practical bases for assessment of cardiorespiratory fitness and muscle status in adults in healthcare settings

Given their importance in predicting clinical outcomes, cardiorespiratory fitness (CRF) and muscle status can be considered new vital signs. However, they are not routinely evaluated in healthcare settings. Here, we present a comprehensive review of the epidemiological, mechanistic, and practical bases of the evaluation of CRF and muscle status in adults in primary healthcare settings. We highlight the importance of CRF and muscle status as predictors of morbidity and mortality, focusing on their association with cardiovascular and metabolic outcomes. Notably, adults in the best quartile of CRF and muscle status have as low as one-fourth the risk of developing some of the most common chronic metabolic and cardiovascular diseases than those in the poorest quartile. The physiological mechanisms that underlie these epidemiological associations are addressed. These mechanisms include the fact that both CRF and muscle status reflect an integrative response to the body function. Indeed, muscle plays an active role in the development of many diseases by regulating the body's metabolic rate and releasing myokines, which modulate metabolic and cardiovascular functions. We also go over the most relevant techniques for assessing peak oxygen uptake as a surrogate of CRF and muscle strength, mass, and quality as surrogates of muscle status in adults. Finally, a clinical case of a middle-aged adult is discussed to integrate and summarize the practical aspects of the information presented throughout. Their clinical importance, the ease with which we can assess CRF and muscle status using affordable techniques, and the availability of reference values, justify their routine evaluation in adults across primary healthcare settings.

Associations of cardiorespiratory fitness and body mass index with incident restrictive spirometry pattern

OBJECTIVES

Restrictive spirometry pattern (RSP) suggests an impairment of lung function associated with a significantly increased risk of premature mortality. We evaluated the independent and joint associations of cardiorespiratory fitness (CRF) and body mass index with incident RSP.

METHODS

Data from the Aerobics Centre Longitudinal Study included 12 360 participants (18-82 years). CRF was assessed by maximal treadmill test and categorised into five groups. Body mass index was categorised into normal weight (<25.0 kg/m²), overweight (25.0-29.9 kg/m²) or obesity (≥30.0 kg/m²). RSP was defined as the simultaneous occurrence of forced expiratory volume in 1 s/force vital capacity ≥lower limit of normal and forced vital capacity <lower limit of normal.

RESULTS

There were 900 (7.3%) cases of RSP (mean follow-up: 6.9 years). Compared with category 1 ('least fit'), HRs (95% CIs) of RSP were 0.78 (0.63 to 0.96), 0.68 (0.54 to 0.86), 0.70 (0.55 to 0.88) and 0.59 (0.45 to 0.77) in categories 2, 3, 4 and 5 (most fit), respectively, after adjusting for confounders including body mass index. Compared with normal weight, HRs (95% CIs) of RSP were 1.06 (0.91 to 1.23) and 1.30 (1.03 to 1.64) in overweight and obese, respectively. However, the association between obesity and RSP was attenuated when additionally adjusting for CRF (HR 1.08, 95% CI 0.84 to 1.39). Compared with the 'unfit and overweight/obese' group, HRs (95% CIs) for RSP were 1.35 (0.98 to 1.85), 0.77 (0.63 to 0.96) and 0.70 (0.56 to 0.87) in the 'unfit and normal weight,' 'fit and overweight/obese' and 'fit and normal weight' groups, respectively.

CONCLUSIONS

Low CRF was associated with a greater incidence of RSP, irrespective of body mass index. Future studies are needed to explore potential underlying mechanisms of this association and to prospectively evaluate if improving CRF reduces the risk of developing RSP.

Type 2 Diabetes Incidence and Mortality: Associations with Physical Activity, Fitness, Weight Loss, and Weight Cycling

Cardiometabolic diseases, including cardiovascular disease (CVD) and type 2 diabetes (T2D), are the leading cause of death globally. Because T2D and obesity are strongly associated, weight loss is the cornerstone of treatment. However, weight loss is rarely sustained, which may lead to weight cycling, which is associated with increased mortality risk in patients with T2D. Meta-analyses show that weight loss is not generally associated with reduced mortality risk in T2D, whereas weight cycling is associated with increased all-cause and CVD mortality. This may be attributable in part to increased variability in CVD risk factors that often accompany weight cycling, which studies show is consistently associated with adverse CVD outcomes in patients with T2D. The inconsistent associations between weight loss and mortality risk in T2D, and consistent findings of elevated mortality risk associated with weight cycling, present a conundrum for a weight-loss focused T2D prevention and treatment strategy. This is further complicated by the findings that among patients with T2D, mortality risk is lowest in the body mass index (BMI) range of ~25-35 kg/ m 2 . Because this "obesity paradox" has been consistently demonstrated in 7 meta-analyses, the lower mortality risk for individuals with T2D in this BMI range may not be all that paradoxical. Physical activity (PA), cardiorespiratory fitness (CRF), and muscular fitness (MF) are all associated with reduced risk of T2D, and lower risk of CVD and all-cause mortality in individuals with T2D. Reducing sedentary behavior, independent of PA status, also is strongly associated with reduced risk of T2D. Improvements in cardiometabolic risk factors with exercise training are comparable to those observed in weight loss interventions, and are largely independent of weight loss. To minimize risks associated with weight cycling, it may be prudent to adopt a weight-neutral approach for prevention and treatment of individuals with obesity and T2D by focusing on increasing PA and improving CRF and MF without a specific weight loss goal.

Independent and joint associations of non-exercise cardiorespiratory fitness and obesity with risk of type 2 diabetes mellitus in the Rural Chinese Cohort Study

BACKGROUND AND AIMS

An association between cardiorespiratory fitness (CRF) and type 2 diabetes mellitus (T2DM) has not been established in the Chinese population. This study aimed to estimate the independent and joint associations of CRF and obesity with T2DM incidence in the rural Chinese population.

METHODS AND RESULTS

We conducted a prospective study of 11,825 non-T2DM subjects among rural Chinese adults. Cox regression models were used to estimate the independent and joint associations between CRF and obesity exposure on T2DM. Restricted cubic splines were used to model the dose-response association. During a median follow-up of 6.01 years, 835 participants developed T2DM. In comparison to quartile 1 of CRF, the multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) of quartiles 2, 3, 4 were 0.75 (0.61-0.91), 0.54 (0.43-0.68), and 0.42 (0.32-0.55), respectively. When stratified by sex, the results were similar. Joint analyses showed that overweight/obesity-unfit individuals had a 2.28 times higher risk of developing T2DM than the normal weight-fit referent (HR 2.28, 95% CI 1.84-2.83; P_interaction <0.001). The risk for the overweight/obesity-fit category (HR 1.61, 95% CI 1.21-2.15) was larger than for the normal weight-unfit category (HR 1.38, 95% CI 0.97-1.95) versus the normal weight-fit referent. Similar joint associations for waist circumference and CRF with T2DM were also observed.

CONCLUSION

A negative association was observed between CRF and risk of T2DM. Overweight/obese or abdominal obesity and unfit participants showed the highest risks of T2DM. It is therefore strongly recommended that fitness-enhancing be encouraged for the prevention of T2DM, especially among obesity participants.

The combination of cardiorespiratory fitness and muscular fitness, and prevalence of diabetes mellitus in middle-aged and older men: WASEDA'S Health Study

Background

Although the negative relationship between cardiorespiratory fitness (CRF) or muscular fitness and diabetes mellitus were respectively observed in many previous studies, there is still a lack of studies that include CRF and muscular fitness simultaneously. Therefore, this study aimed to investigate the relationship between the combination of CRF and muscular fitness and diabetes through a cross-sectional study. 

Methods

This study was part of WASEDA'S Health Study, a cohort study launched in 2014. We used a part of the baseline data collected for this study. Maximal exercise test using a cycle ergometer and leg extension power (LEP) test were respectively used to evaluate CRF and muscular fitness. Since LEP is affected by body weight, relative LEP (rLEP) which is LEP per body weight, was used as an index of muscular fitness. 796 men (56.5 ± 10.4 years old) who completed a medical examination and fitness tests, were divided into two groups based on CRF and rLEP, respectively. The prevalence of diabetes was collected based on a self-reported questionnaire or blood test. Odds ratios and 95% confidence intervals (CIs) for the prevalence of diabetes were obtained using logistic regression models while adjusting for age, body mass index, exercise habits, family history of diabetes, smoking habits, and drinking habits.

Results

55 (7%) participants had diabetes. Compared to participants with lower CRF or rLEP, the odds ratio (95% CIs) of diabetes in those with higher CRF or rLEP was 0.46 (0.21–0.98) or 0.34 (0.16–0.74), respectively. Furthermore, using the lower CRF and lower rLEP group as the reference, the odds ratio (95% CIs) for the lower CRF and higher rLEP group was 0.32 (0.12–0.88), and higher CRF and higher rLEP group was 0.21 (0.07–0.63), after adjusting for potential confounding factors.

Conclusions

CRF and rLEP have independent and joint inverse associations with diabetes prevalence. In addition, participants with high CRF and high rLEP had a lower prevalence of diabetes compared to those with only high CRF or only high rLEP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12971-x.

Comparison of Fitness and Physical Activity Levels of Obese People with Hypertension

This study assessed the relationships between the current level of physical activity (PA) and PA in childhood and the level of physical fitness (PF) of obese people aged 40+ with co-existing hypertension (HT). The study included 82 obese patients with co-existing HT in their history. In order to assess the level of PA, we used the IPAQ. PF was assessed by observing the performance of patients in a fitness test (a 30-s chair stand, a handgrip strength test, a sit-and-reach test, a one leg stand test, a plank test, a wall squat test, and a 2-min step-in-place test). According to the IPAQ category, 24.4% were classified as having a high level of PA, 45.1% a sufficient level of PA, and 30.5% an insufficient level of PA. We noted that the higher the level of PA, the higher the PF—even in obese participants with HT. On the other hand, co-existing diabetes lowered almost all analysed parameters, both biochemical and fitness. The current PA level, a deficiency in which seems to be related to low PF and/or HT, does seem to be related to the degree of PF.

Association of Estimated Cardiorespiratory Fitness in Midlife With Cardiometabolic Outcomes and Mortality

IMPORTANCE

The associations of estimated cardiorespiratory fitness (eCRF) during midlife with subclinical atherosclerosis, arterial stiffness, incident cardiometabolic disease, and mortality are not well understood.

OBJECTIVE

To examine associations of midlife eCRF with subclinical atherosclerosis, arterial stiffness, incident cardiometabolic disease, and mortality.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included 2962 participants in the Framingham Study Second Generation (conducted between 1979 and 2001). Data were analyzed from January 2020 to June 2020.

EXPOSURES

eCRF was calculated using sex-specific algorithms (including age, body mass index, waist circumference, physical activity, resting heart rate, and smoking) and was categorized as: (1) tertiles of standardized eCRF at examination cycle 7 (1998 to 2001); (2) tertiles of standardized average eCRF between examination cycles 2 and 7 (1979 to 2001); and (3) eCRF trajectories between examination cycles 2 and 7, with the lowest tertile or trajectory (ie, low eCRF) as referent group.

MAIN OUTCOMES AND MEASURES

Subclinical atherosclerosis (carotid intima-media thickness [CIMT], coronary artery calcium [CAC] score); arterial stiffness (carotid-femoral pulse wave velocity [-1000/CFPWV]); incident hypertension, diabetes, chronic kidney disease (CKD), cardiovascular disease (CVD), and mortality after examination cycle 7.

RESULTS

A total of 2962 participants were included in this cohort study (mean [SD] age, 61.5 [9.2] years; 1562 [52.7%] women). The number of events or participants at risk after examination cycle 7 (at a mean follow-up of 15 years) was 728 of 1506 for hypertension, 214 of 2268 for diabetes, 439 of 2343 for CKD, 500 of 2608 for CVD, and 770 of 2962 for mortality. Compared with the low eCRF reference value, high single examination eCRF was associated with lower CFPWV (β [SE], -11.13 [1.33] ms/m) and CIMT (β [SE], -0.12 [0.05] mm), and lower risk of hypertension (hazard ratio [HR], 0.63; 95% CI, 0.46-0.85), diabetes (HR, 0.38; 95% CI, 0.23-0.62), and CVD (HR, 0.71; 95% CI, 0.53-0.95), although it was not associated with CKD or mortality. Similarly, compared with the low eCRF reference, high eCRF trajectories and mean eCRF were associated with lower CFPWV (β [SE], -11.85 [1.89] ms/m and -10.36 [1.54] ms/m), CIMT (β [SE], -0.19 [0.06] mm and -0.15 [0.05] mm), CAC scores (β [SE], -0.67 [0.25] AU and -0.63 [0.20] AU), and lower risk of hypertension (HR, 0.54; 95% CI, 0.34-0.87 and HR, 0.48; 95% CI, 0.34-0.68), diabetes (HR, 0.27; 95% CI, 0.15-0.48 and HR, 0.31; 95% CI, 0.18-0.54), CKD (HR, 0.63; 95% CI, 0.40-0.97 and HR, 0.64; 95% CI, 0.44-0.94), and CVD (HR, 0.46; 95% CI, 0.31-0.68 and HR, 0.43; 95% CI, 0.30-0.60). Compared with the reference value, a high eCRF trajectory was associated with lower risk of mortality (HR, 0.69; 95% CI, 0.50-0.95).

CONCLUSIONS AND RELEVANCE

In this cohort study, higher midlife eCRF was associated with lower burdens of subclinical atherosclerosis and vascular stiffness, and with a lower risk of hypertension, diabetes, chronic kidney disease, cardiovascular disease, and mortality. These findings suggest that midlife eCRF may serve as a prognostic marker for subclinical atherosclerosis, arterial stiffness, cardiometabolic health, and mortality in later life.

The association of fitness and fatness with intermediate hyperglycemia incidence in women: A cohort study

The purpose of this study was to examine the associations of cardiorespiratory fitness, general adiposity, and central adiposity with incident intermediate hyperglycemia (IH) in women. We conducted a prospective cohort study of 1534 women aged 20-79 years old who had an annual health check-up with no history of major chronic diseases. At baseline, fitness was assessed by a Balke graded exercise test, and the estimated metabolic equivalents were used to create quartile groups. Women were also grouped based on their body mass index (<25 kg/m², 25-29.9 kg/m², and ≥ 30 kg/m²) and waist-to-height ratio (≥0.50 or < 0.50). Cox proportional hazards models were conducted to assess the association of fitness and fatness variables with incident IH defined as fasting glucose of 5.6-6.9 mmol/L. Overall, 18.1% (n = 277) of the women developed IH during an average follow-up of 5.06 years. Fitness, body mass index, and waist-to-height ratio at baseline were the independent predictors of the IH incidence in separate age-adjusted models; yet when all three variables were included in the same model along with confounding variables, only fitness remained significant and demonstrated a clear inverse association with incident IH (P-for-trend <0.001). Health promotion efforts should focus on improving fitness for the prevention of IH in women.

The association between cardiorespiratory fitness, liver fat and insulin resistance in adults with or without type 2 diabetes: a cross-sectional analysis

Background

Exercise-induced improvements in cardiorespiratory fitness (CRF) often coincide with improvements in insulin sensitivity and reductions in liver fat content. However, there are limited data concerning the relationship between CRF and liver fat content in adults with varying degrees of metabolic dysfunction.

Methods

The aim of this study was to examine the association between CRF, liver fat content, and insulin resistance in inactive adults with obesity and with or without type 2 diabetes (T2D), via cross-sectional analysis. CRF was determined via a graded exercise test. Liver fat content was assessed via proton magnetic resonance spectroscopy and insulin resistance was assessed via homeostatic model of insulin resistance (HOMA-IR). A partial correlation analysis, controlling for age and gender, was performed to determine the association between CRF, demographic, cardiometabolic, and anthropometric variables. Independent t tests were performed to compare cardiometabolic outcomes between participants with T2D and participants without T2D.

Results

Seventy-two adults (46% male) with a mean age of 49.28 ± 10.8 years, BMI of 34.69 ± 4.87 kg/m², liver fat content of 8.37 ± 6.90%, HOMA-IR of 3.07 ± 2.33 and CRF of 21.52 ± 3.77 mL/kg/min participated in this study. CRF was inversely associated with liver fat content (r = − 0.28, p = 0.019) and HOMA-IR (r = − 0.40, p < 0.001). Participants with T2D had significantly higher liver fat content (+ 3.66%, p = 0.024) and HOMA-IR (+ 2.44, p < 0.001) than participants without T2D. Participants with T2D tended to have lower CRF than participants without T2D (− 1.5 ml/kg/min, p = 0.094).

Conclusion

CRF was inversely associated with liver fat content and insulin resistance. Participants with T2D had lower CRF than those without T2D, however, the difference was not statistically significant. Further longitudinal studies are required to elucidate the relationship between CRF and the progression of obesity-related diseases such as T2D.

Registration: ACTRN12614001220651 (retrospectively registered on the 19th November 2014) and ACTRN12614000723684 (prospectively registered on the 8th July 2014).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-021-00261-9.

Plasma Interleukin-10 and Cholesterol Levels May Inform about Interdependences between Fitness and Fatness in Healthy Individuals

Relationships between demographic, anthropometric, inflammatory, lipid and glucose tolerance markers in connection with the fat but fit paradigm were investigated by supervised and unsupervised learning. Data from 81 apparently healthy participants (87% females) were used to generate four classes of fatness and fitness. Principal Component Analysis (PCA) revealed that the principal component was preponderantly composed of glucose tolerance parameters. IL-10 and high-density lipoprotein, low-density lipoprotein (LDL), and total cholesterol, along with body mass index (BMI), were the most important features according to Random Forest based recursive feature elimination. Decision Tree classification showed that these play a key role into assigning each individual in one of the four classes, with 70% accuracy, and acceptable classification agreement, κ = 0.54. However, the best classifier with 88% accuracy and κ = 0.79 was the Naïve Bayes. LDL and BMI partially mediated the relationship between fitness and fatness. Although unsupervised learning showed that the glucose tolerance cluster explains the highest quote of the variance, supervised learning revealed that the importance of IL-10, cholesterol levels and BMI was greater than the glucose tolerance PCA cluster. These results suggest that fitness and fatness may be interconnected by anti-inflammatory responses and cholesterol levels. Randomized controlled trials are needed to confirm these preliminary outcomes.

Nativity and prevalence of cardiometabolic diseases among U.S. Asian immigrants

AIMS

Acculturation has been shown to be an important factor for immigrants' health in the United States. We investigate whether nativity is associated with a greater risk for cardiometabolic diseases among Asian Americans (Asians) vs. non-Hispanic whites (whites).

METHODS

Based on data from the U.S. National Health Interview Survey in 2006-2015, 146,862 Asians and whites aged ≥30 years were evaluated. Nativity as a proxy for acculturation was defined using a combination of birthplace and the duration of U.S. residency. Cardiometabolic diseases were defined based on self-reported diagnoses of diabetes, prediabetes, or cardiovascular diseases (CVD). Using 10-year pooled data accounting for complex sampling designs and weights, multiple logistic regression models were used to assess associations. Four Asian subgroups, including Chinese, Filipinos, Asian Indians and other Asians, were evaluated in subgroup analyses.

RESULTS

Compared to U.S.-born whites, prevalent type 2 diabetes and prediabetes were higher among Asians depending on nativity. However, the prevalence of CVD was lower among Asians than among whites regardless of nativity (OR≥15 years = 0.5 [95% CI:0.5-0.6], ORU.S-born = 0.7 [95% CI:0.6-0.8]). In addition, compared to U.S.-born whites, prevalent type 2 diabetes and prediabetes increased with an increasing length of U.S. residency for foreign-born Asians among Asians overall (≥15 years: ORdiabetes = 1.5 [95% CI:1.3-1.7]; ORprediabetes = 1.3 [95% CI:1.2-1.6]) and Asian Indians and Filipinos. Furthermore, a significant graded association between prediabetes and length of U.S. residency was found among foreign-born Asians.

CONCLUSIONS

The prevalence of diabetes and prediabetes is higher among Asian immigrants who have spent more years in the U.S., than those in U.S.-born whites. Monitoring and prevention efforts for diabetes should target this group.

Exercise and metabolic health: beyond skeletal muscle

Regular exercise is a formidable regulator of insulin sensitivity and overall systemic metabolism through both acute events driven by each exercise bout and through chronic adaptations. As a result, regular exercise significantly reduces the risks for chronic metabolic disease states, including type 2 diabetes and non-alcoholic fatty liver disease. Many of the metabolic health benefits of exercise depend on skeletal muscle adaptations; however, there is plenty of evidence that exercise exerts many of its metabolic benefit through the liver, adipose tissue, vasculature and pancreas. This review will highlight how exercise reduces metabolic disease risk by activating metabolic changes in non-skeletal-muscle tissues. We provide an overview of exercise-induced adaptations within each tissue and discuss emerging work on the exercise-induced integration of inter-tissue communication by a variety of signalling molecules, hormones and cytokines collectively named 'exerkines'. Overall, the evidence clearly indicates that exercise is a robust modulator of metabolism and a powerful protective agent against metabolic disease, and this is likely to be because it robustly improves metabolic function in multiple organs. Graphical abstract.

Cardiorespiratory Fitness, Body Mass Index, and Markers of Insulin Resistance in Apparently Healthy Women and Men

BACKGROUND

Insulin resistance may be present in healthy adults and is associated with poor health outcomes. Obesity is a risk factor for insulin resistance, but most obese adults do not have insulin resistance. Fitness may be protective, but the association between fitness, weight, and insulin resistance has not been studied in a large population of healthy adults.

METHODS

A cross-sectional analysis of cardiorespiratory fitness, body mass index, and markers of insulin resistance was performed. Study participants were enrolled at the Cooper Clinic in Dallas, Texas. The analysis included 19,263 women and 48,433 men with no history of diabetes or cardiovascular disease. Cardiorespiratory fitness was measured using exercise treadmill testing. Impaired fasting glucose (100-125 mg/dL) and elevated fasting triglycerides (≥150 mg/dL) were used as a markers of insulin resistance.

RESULTS

Among individuals with normal weight, poor fitness was associated with 2.2-fold higher odds of insulin resistance in women (1.4-3.6; P = .001) and 2.8-fold higher odds in men (2.1-3.6; P <.001). The impact of fitness remained significant for overweight and obese individuals, with the highest risk group being the unfit obese. Among obese women, the odds ratio for insulin resistance was 11.0 for fit women (8.7-13.9; P <.001) and 20.3 for unfit women (15.5-26.5; P <.001). Among obese men, the odds ratio for insulin resistance was 7.4 for fit men (6.7-8.2; P < .001) and 12.9 for unfit men (11.4-14.6; P < .001).

CONCLUSIONS

Independent of weight, poor fitness is associated with risk of insulin resistance. Obese individuals, particularly women, may benefit from the greatest absolute risk reduction by achieving moderate fitness.

Independent and combined associations of cardiorespiratory fitness and muscle strength with metabolic syndrome in older adults: A cross-sectional study

BACKGROUND

Studies have shown that low cardiorespiratory fitness (CRF) and low muscle strength are independently associated with metabolic syndrome (MetS) in older adults. This study investigated the isolated and combined associations of low CRF and muscle strength with MetS in older adults.

METHODS

This cross-sectional study included 184 older adults (71% women; aged 65.6 ± 4.3 years) without a prior history of cardiovascular disease. CRF and muscle strength were assessed by the six-minute walking test and 30-s chair stand test, respectively. Results below the 25th percentile of the cohort were used to define low CRF and low muscle strength. MetS was defined according to NCEP-ATP III criteria. Poisson's regression with robust variance was used to determine the prevalence ratio (PR) for MetS. Reference group was composed by older adults with both CRF and muscle strength above 25th percentile.

RESULTS

Prevalence of low CRF, low muscle strength, and combined low CRF and muscle strength was 22.8%, 17.9%, and 10.9%, respectively. The prevalence of MetS was 56.5% in the full cohort. Isolated low CRF (PR 1.05, 95% CI 0.73 to 1.52; p = 0.793) and muscle strength (PR 1.09, 95% CI 0.74 to 1.61; p = 0.651) were not associated with MetS in the adjusted analysis. Combined low CRF and muscle strength was associated with MetS (PR 1.45, 95% CI 1.09 to 1.93; p = 0.011).

CONCLUSIONS

Older adults with combined, but not isolated, low CRF and muscle strength showed an increased risk for MetS.

A position statement on screening and management of prediabetes in adults in primary care in Australia

Prediabetes has a high prevalence, with early detection essential to facilitate optimal management to prevent the development of conditions such as type 2 diabetes and cardiovascular disease. Prediabetes can include impaired fasting glucose, impaired glucose tolerance and elevated HbA1c. This position statement outlines the approaches to screening and management of prediabetes in primary care. There is good evidence to implement intensive, structured lifestyle interventions for individuals with impaired glucose tolerance. The evidence for those with impaired fasting glucose or elevated HbA1c is less clear, but individuals should still be provided with generalised healthy lifestyle strategies. A multidisciplinary approach is recommended to implement healthy lifestyle changes through education, nutrition and physical activity. Individuals should aim to lose weight (5-10% of body mass) using realistic and sustainable dietary approaches supported by an accredited practising dietitian, where possible. Physical activity and exercise should be used to facilitate weight maintenance and reduce blood glucose. Moderate-vigorous intensity aerobic exercise and resistance training should be prescribed by an accredited exercise physiologist, where possible. When indicated, pharmacotherapy, metabolic surgery and psychosocial care should be considered, in order to enhance the outcomes associated with lifestyle change. Individuals with prediabetes should generally be evaluated annually for their diabetes status.

Obesity Phenotypes, Diabetes, and Cardiovascular Diseases

This review addresses the interplay between obesity, type 2 diabetes mellitus, and cardiovascular diseases. It is proposed that obesity, generally defined by an excess of body fat causing prejudice to health, can no longer be evaluated solely by the body mass index (expressed in kg/m²) because it represents a heterogeneous entity. For instance, several cardiometabolic imaging studies have shown that some individuals who have a normal weight or who are overweight are at high risk if they have an excess of visceral adipose tissue-a condition often accompanied by accumulation of fat in normally lean tissues (ectopic fat deposition in liver, heart, skeletal muscle, etc). On the other hand, individuals who are overweight or obese can nevertheless be at much lower risk than expected when faced with excess energy intake if they have the ability to expand their subcutaneous adipose tissue mass, particularly in the gluteal-femoral area. Hence, excessive amounts of visceral adipose tissue and of ectopic fat largely define the cardiovascular disease risk of overweight and moderate obesity. There is also a rapidly expanding subgroup of patients characterized by a high accumulation of body fat (severe obesity). Severe obesity is characterized by specific additional cardiovascular health issues that should receive attention. Because of the difficulties of normalizing body fat content in patients with severe obesity, more aggressive treatments have been studied in this subgroup of individuals such as obesity surgery, also referred to as metabolic surgery. On the basis of the above, we propose that we should refer to obesities rather than obesity.

Validation of Maximal, Submaximal, and Nonexercise Indirect [Formula: see text]O2max Estimations at 2600 m Altitude

Aim: To study the criterion validity of three indirect maximal oxygen uptake ([Formula: see text]O₂max) assessment equations at altitude. Methods: We studied 64 young adults (53% men) at Bogota, Colombia (2600 m altitude). Direct [Formula: see text]O₂max was measured by indirect calorimetry using a maximal incremental treadmill protocol. Indirect [Formula: see text]O₂max was estimated by two exercise field tests (the 20-m shuttle-run test [20-MST] and the 2-km walking test (UKK)) and one nonexercise method (the perceived functional ability-physical activity rating questionnaire [PFA-PAR]). Altitude-adjusted PFA-PAR was estimated as a 13% linear reduction in PFA-PAR. We calculated Lin concordance coefficients (LCC) and standard error of the estimates (SEEs), and we performed Bland-Altman analyses for each indirect method. Results: Mean [Formula: see text]O₂max was 41.2 ± 5.8 mL/kg/min in men and 32.2 ± 3.6 mL/kg/min in women. We found the highest agreement with direct [Formula: see text]O₂max for the 20-MST (LCC = 0.79, SEE = 3.91 mL/kg/min), followed in order by the altitude-adjusted PFA-PAR (LCC = 0.71, SEE = 4.12 mL/kg/min), the UKK (LCC = 0.67, SEE = 5.48 mL/kg/min), and the unadjusted PFA-PAR (LCC = 0.57, SEE = 4.75 mL/kg/min). The unadjusted PFA-PAR tended to overestimate [Formula: see text]O₂max, but Bland-Altman analysis showed that this bias disappeared after altitude adjustment. Conclusion: Several maximal, submaximal, and nonexercise methods provide estimates of [Formula: see text]O₂max with acceptable validity for use in epidemiological studies of populations living at moderate altitude.

Leisure-Time Running Reduces the Risk of Incident Type 2 Diabetes

OBJECTIVES

We examined the overall association as well as the dose-response relationship between leisure-time running and incident type 2 diabetes.

METHODS

Participants were 19,347 adults aged 18-100 years who were free of cardiovascular disease, cancer, and diabetes at baseline, and who received at least 2 extensive preventive medical examinations between 1974 and 2006. Running and other types of aerobic physical activity were assessed by self-reported leisure-time activities. Type 2 diabetes was defined as fasting glucose ≥126 mg/dL (7.0 mmol/L), physician diagnosis, or insulin use.

RESULTS

During an average follow-up of 6.5 years, 1015 adults developed type 2 diabetes. Approximately 29.5% of adults participated in leisure-time running at baseline. Runners had a 28% (hazard ratio [HR] 0.72; 95% confidence interval [CI], 0.62-0.84) lower risk of developing type 2 diabetes compared with nonrunners during follow-up. The HRs (95% CIs) of type 2 diabetes were 0.98 (0.75-1.28), 0.69 (0.51-0.92), 0.62 (0.45-0.85), 0.78 (0.59-1.04), and 0.57 (0.42-0.79) across quintiles of running time (minutes/week) compared with nonrunners after adjusting for potential confounders, including levels of nonrunning aerobic physical activity. Similar dose-response relationships between running distance (miles/week), frequency (times/week), total amount (MET-minutes/week), and speed (mph) were also observed.

CONCLUSIONS

Participating in leisure-time running is associated with a lower risk of developing type 2 diabetes in adults. Consistent linear dose-response relationships were observed between various running parameters and incident type 2 diabetes, supporting the prescription of running to prevent type 2 diabetes.

Intrinsic High Aerobic Capacity in Male Rats Protects Against Diet-Induced Insulin Resistance

Low aerobic capacity increases the risk for insulin resistance but the mechanisms are unknown. In this study, we tested susceptibility to acute (3-day) high-fat, high-sucrose diet (HFD)-induced insulin resistance in male rats selectively bred for divergent intrinsic aerobic capacity, that is, high-capacity running (HCR) and low-capacity running (LCR) rats. We employed hyperinsulinemic-euglycemic clamps, tracers, and transcriptome sequencing of skeletal muscle to test whether divergence in aerobic capacity impacted insulin resistance through systemic and tissue-specific metabolic adaptations. An HFD evoked decreased insulin sensitivity and insulin signaling in muscle and liver in LCR rats, whereas HCR rats were protected. An HFD led to increased glucose transport in skeletal muscle (twofold) of HCR rats while increasing glucose transport into adipose depots of the LCR rats (twofold). Skeletal muscle transcriptome revealed robust differences in the gene profile of HCR vs LCR on low-fat diet and HFD conditions, including robust differences in specific genes involved in lipid metabolism, adipogenesis, and differentiation. HCR transcriptional adaptations to an acute HFD were more robust than for LCR and included genes driving mitochondrial energy metabolism. In conclusion, intrinsic aerobic capacity robustly impacts systemic and skeletal muscle adaptations to HFD-induced alterations in insulin resistance, an effect that is likely driven by baseline differences in oxidative capacity, gene expression profile, and transcriptional adaptations to an HFD.

Association of Muscular Strength and Incidence of Type 2 Diabetes

OBJECTIVE

To examine the association between muscular strength and incident type 2 diabetes, independent of cardiorespiratory fitness (CRF).

PATIENTS AND METHODS

A total of 4681 adults aged 20 to 100 years who had no type 2 diabetes at baseline were included in the current prospective cohort study. Participants underwent muscular strength tests and maximal treadmill exercise tests between January 1, 1981, and December 31, 2006. Muscular strength was measured by leg and bench press and categorized as age group- and sex-specific thirds (lower, middle, and upper) of the combined strength score. Type 2 diabetes was defined on the basis of fasting plasma glucose levels, insulin therapy, or physician diagnoses.

RESULTS

During a mean follow-up of 8.3 years, 229 of the 4681 patients (4.9%) had development of type 2 diabetes. Participants with the middle level of muscular strength had a 32% lower risk of development of type 2 diabetes (hazard ratio, 0.68; 95% confidence interval, 0.49-0.94; P=.02) compared with those with the lower level of muscular strength after adjusting for potential confounders, including estimated CRF. However, no significant association between the upper level of muscular strength and incident type 2 diabetes was observed.

CONCLUSION

A moderate level of muscular strength is associated with a lower risk of type 2 diabetes, independent of estimated CRF. More studies on the dose-response relationship between muscular strength and type 2 diabetes are needed.

Type 1 versus type 2 diabetes and thromboembolic risk in patients with atrial fibrillation: A Danish nationwide cohort study

BACKGROUND

Atrial fibrillation is a common cause of stroke, and diabetes increases stroke risk. Stroke risk may vary depending on the type of diabetes. We investigated whether type 1 and type 2 diabetes are associated with different risks of thromboembolism among patients with atrial fibrillation.

METHODS

We used data from Danish nationwide registries to identify patients with a prior diagnosis of diabetes and an incident nonvalvular atrial fibrillation diagnosis in the period of January 1, 2005 to December 31, 2015. Cox regression analysis was used to estimate hazard ratios (HR) for the outcome thromboembolism.

RESULTS

The study population included 10,058 patients with a prior diagnosis of diabetes and an incident diagnosis of atrial fibrillation. At three-year follow-up, type 2 diabetes was not associated with a higher risk of thromboembolism compared to type 1 diabetes, with an adjusted HR of 1.15 (95% CI: 0.91-1.44). In an age-stratified analysis, patients aged below 65 years of age had an adjusted HR of 1.97 (95% CI: 1.07-3.61), whereas patients aged 65-74 years or ≥75 years had adjusted HRs of 0.99 (95% CI: 0.67-1.46) and 1.10 (95% CI: 0.80-1.51), respectively.

CONCLUSION

We found no overall credible association between the type of diabetes and risk of thromboembolism in this cohort of non-anticoagulated patients with incident atrial fibrillation. Nonetheless, the subset of patients aged below 65 years of age displayed a higher risk of thromboembolism among patients with type 2 diabetes as compared to patients with type 1 diabetes.

Association Between Cardiorespiratory Fitness and Risk of Type 2 Diabetes: A Meta-Analysis

OBJECTIVE

This meta-analysis aimed to (1) quantify the association of cardiorespiratory fitness (CRF) with type 2 diabetes risk in the general population and statin users and (2) investigate the joint effects of CRF and fatness with type 2 diabetes risk.

METHODS

Databases were searched for cohort studies reporting the association between CRF and type 2 diabetes risk. Summary hazard ratios (HRs) were obtained using random-effects models.

RESULTS

Fifteen studies were included. The HRs of type 2 diabetes for every 1-metabolic equivalent increase in CRF were 0.90 (95% CI: 0.86-0.94) for the general population and 0.92 (95% CI: 0.87-0.97) for statin users, and the HRs were linearly shaped (both P_nonlinearity  > 0.40). Compared with the nonstatin cohort, there was an increased risk of type 2 diabetes in statin users with the lowest and moderate CRF categories, but this was not present in the highest CRF category. The HR of type 2 diabetes for overweight/obesity-fit category versus normal weight-fit category was larger than that of the normal weight-unfit category versus the normal weight-fit category (P_interaction   = 0.004).

CONCLUSIONS

There was an inverse and dose-dependent association between CRF and type 2 diabetes risk. High CRF may eliminate the diabetogenic effect from statins, yet decreased body weight index seems superior in preventing type 2 diabetes.

The relationship of one-leg standing time with peripheral nerve function and clinical neuropathy in patients with type 2 diabetes

Objective

This study aimed at exploring physical fitness including postural stability in relation to peripheral nerve function and clinical neuropathy in patients with type 2 diabetes across a wide range of ages.

Methods

We analyzed data collected from 139 patients with type 2 diabetes aged between 19 and 81 years, which included the peripheral nerve conduction parameters and coefficient of variation for normal R-R intervals (CVRR) at rest and during deep breathing. The results of neurological examinations to diagnose probable and confirmed diabetic neuropathies based on the minimal criteria proposed by the Toronto diabetic neuropathy expert group and a battery of physical fitness tests including one-leg standing time with eyes open were also assessed. Multiple linear and logistic regressions were used to estimate the relationships of the physical fitness measures with the parameters of peripheral and cardiac autonomic nerve functions and clinical neuropathies, respectively. Receiver operating characteristic curves were generated to depict the relation between sensitivity and specificity of one-leg standing time for probable and confirmed neuropathies.

Results

After adjustment for age and other potential confounders, one-leg standing time correlated with peripheral and cardiac autonomic nerve functions as well as with probable and confirmed neuropathies. The one-leg standing time of 23 s was found to be 66 and 63% sensitive and 81 and 77% specific for diagnosing probable and confirmed neuropathies, respectively.

Conclusions

Short one-leg standing time was associated with peripheral and cardiac autonomic nerve dysfunction and clinical neuropathy in patients with type 2 diabetes, independent of age.

Cardiorespiratory fitness and development of abdominal obesity

Both, cardiorespiratory fitness and abdominal obesity are independently associated with developing cardiovascular disease and its risk factors. However, the relationship between both attributes is unclear. We examine the relationship between cardiorespiratory fitness and the risk of developing abdominal obesity, and secondarily, other adiposity measures. Retrospective observational study of a cohort of 1284 sedentary patients, who had participated in a clinical trial of physical activity promotion carried out in Spain (2003-2007). At baseline, they were free of cardiovascular disease, hypertension, diabetes, dyslipidemia and/or abdominal obesity, with an indirect VO₂max measurement, were 19-80 years old, 62% women, and had completed the two year follow-up. The exposure factor was cardiorespiratory fitness categorized as high, moderate or low, according to tertiles of VO₂max values. The main outcome measure was the risk of developing abdominal obesity, as defined by waist circumference >102 (men) and >88 (women) cm. Secondary outcomes were the risk of developing: general obesity, excess body fat, and their combination ("defined" obesity). At two years, 10.5% of the participants had developed abdominal obesity: 6.1% in the high cardiorespiratory fitness tertile, 9.7% in the moderate tertile (adjusted odds ratio, 1.20; 95% confidence interval 0.68-2.10), and 15.7% in the low tertile (adjusted odds ratio, 2.29; 95% confidence interval 1.34-3.91). Moreover, 2.2% of participants in the high cardiorespiratory fitness tertile developed "defined" obesity as did 5.4% in the low tertile (adjusted odds ratio, 2.90; 95% confidence interval 1.15-7.29). Low cardiorespiratory fitness levels are associated with a higher risk of developing abdominal and "defined" obesity.

The Effectiveness of MyPlate and Paleolithic-based Diet Recommendations, both with and without Exercise, on Aerobic Fitness, Muscular Strength and Anaerobic Power in Young Women: A Randomized Clinical Trial

The purpose of this study was to evaluate the effectiveness of recommending a MyPlate or a Paleolithic-based diet, both with and without exercise, on aerobic fitness, strength, and anaerobic power over eight weeks. Participants (n=20) were randomized to one of four groups, (1) a MyPlate diet (MP), (2) Paleolithic-based diet (PD), (3) MyPlate and exercise (MP + Ex), and (4) Paleolithic-based diet and exercise (PD + Ex). The exercise included two days of unsupervised aerobic and resistance exercise. At baseline and final, absolute and relative peak oxygen consumption (absVO_2peak and relVO_2peak), anaerobic power, and upper and lower body strength were determined. Data were analyzed using repeated measures two-way analysis of variance (ANOVA). The ANOVA indicated that there was no significant interaction between time point (TP)*diet (D)*exercise (Ex) for all variables except relVO_2peak (p = 0.016). The MP + Ex group (Δ+4.4 ml·kg^-1·min^-1) had a greater change from baseline compared to the MP group (Δ-2.7 ml·kg^-1·min^-1, p = 0.002), and PD + Ex group (Δ-0.3 ml·kg^-1·min^-1, p = 0.03). The results suggest recommending a MyPlate diet with both aerobic and resistance training are effective at improving aerobic fitness when compared to PD recommendations with exercise, although these conclusions may be confounded by low compliance to exercise recommendations.

Trends in the prevalence of type 2 diabetes and its association with mortality rates in Asians vs. Whites: Results from the United States National Health Interview Survey from 2000 to 2014

AIMS

To identify the prevalence and mortality of type 2 diabetes in Asian Americans (Asians) vs. non-Hispanic whites (Whites).

METHODS

We analyzed a nationally representative sample of 237,354 U.S. adults aged ≥30 years using National Health Interview Survey data from 2000 to 2014 to estimate the prevalence and trends of type 2 diabetes. Additionally, 144,638 Asians and Whites represented in surveys from 2000 to 2009 were included in the mortality analysis with follow-up to 2011.

RESULTS

Type 2 diabetes was higher in Asians than Whites (7.0-11.2 vs. 5.6-8.3%) and increased over time. Prevalence rates increased from 8.1 (2000-2002) to 9.6% (2012-2014) in Asians and from 6.0 (2000-2002) to 7.9% (2012-2014) in Whites (both P < 0.05). The age-standardized mortality rates were 72.7 and 138.8 per 1000 person-years in Asians and Whites with diabetes, respectively, and 58.1 and 77.8 per 1000 person-years, respectively, in those without diabetes. Among Asians and Whites with diabetes, hazard ratios for total and CVD mortality were 0.7 (95% CI: 0.5-0.9) and 0.3 (95% CI: 0.1-0.6), respectively, with no difference in cancer mortality. Asians and Whites without diabetes exhibited no differences in total or cause-specific mortality.

CONCLUSIONS

Type 2 diabetes was more prevalent in Asians, with a significant upward trend since 2000, but overall mortality was lower in Asians than Whites with diabetes. Asians are susceptible to type 2 diabetes; thus, prevention programs are still needed.

Importance of Achieving a "Fit" Cardiorespiratory Fitness Level for Several Years on the Incidence of Type 2 Diabetes Mellitus: A Japanese Cohort Study

Background

The “Physical Activity Reference for Health Promotion 2013” provides “fit” reference values for cardiorespiratory fitness (CRF) for good health. The importance of achieving a fit CRF level for several years on the subsequent prevention of type 2 diabetes mellitus (T2DM) remains to be clarified.

Methods

This cohort study was conducted in 2,235 nondiabetic males aged 21 to 59 years, enrolled in April 1986 through March 1987. We calculated the ratio of the area under the curve (AUC_ratio) for actual measured values and the AUC for the reference values of CRF in each individual during an 8-year measurement period before the baseline. According to whether they met a fit CRF level or not, participants were categorized into groups based on the AUC_ratio (Fit_AUC or Unfit_AUC) and initial CRF (Fit_initial or Unfit_initial), respectively. T2DM was evaluated on health checkups until March 2010.

Results

During the follow-up period, 400 men developed T2DM. After adjustment for confounders, as compared with those in the Fit_AUC group, the hazard ratio (HR) for those in the Unfit_AUC group was 1.33 (95% confidence interval [CI], 1.06–1.65). A combined analysis with the categories of initial value and AUC_ratio showed that, compared with the Fit_initial and Fit_AUC group, the HRs of Fit_initial and Unfit_AUC, Unfit_initial and Fit_AUC, and Unfit_initial and Unfit_AUC groups were 1.41 (95% CI, 0.99–2.00), 1.18 (95% CI, 0.81–1.70), and 1.40 (95% CI, 1.08–1.83), respectively.

Conclusion

Achievement of a fit CRF level established in the Japan physical activity guideline for several years was associated with lower subsequent risk of T2DM.

A systematic review and meta-analysis of cardiorespiratory fitness among Indigenous populations in North America and circumpolar Inuit populations

Indigenous populations experience health disparities including increased obesity, diabetes and cardiovascular disease rates. Cardiorespiratory fitness is beneficial for maintaining positive health outcomes. The objective of this systematic review is to evaluate cardiorespiratory fitness among Indigenous populations including comparisons across genders, Indigenous identities, age groups, decades, socio-demographic variables and in comparison to non-Indigenous groups. Included articles reported various cardiorespiratory fitness measures using maximal treadmill or cycle ergometer tests, 20 m shuttle run, 1 mile run/walk test and 6 min walk test. From 14 databases searched in March 2017, including MEDLINE, EMBASE and Scopus, 1069 citations were evaluated and 39 articles included, representing 32 investigations and 10,579 individuals. First Nations/American Indian (FN/AI) adults have greater cardiorespiratory fitness than Inuit. Inuit and FN/AI men and boys have higher cardiorespiratory fitness than women and girls. Lower cardiorespiratory fitness is associated with obesity, metabolic syndrome and a western lifestyle. Cardiorespiratory fitness has declined among Inuit adults, averaging 51.7 ± 7.9 mL·kg^-1·min^-1 in 1970 to 37.7 ± 6.9 mL·kg^-1·min^-1 in 2000. Among men, FN/AI have greater cardiorespiratory fitness compared to European-descents, and European-descents have greater cardiorespiratory fitness compared to Inuit. The 1 mile run/walk time showed that FN/AI boys, girls, and youth had faster times compared to European-descendants, but 20 m shuttle run showed that European-descent boys and youth advanced to further stages compared to FN/AI populations. Cardiorespiratory fitness is declining, and among some Indigenous populations to lower levels than European-descent populations. Improving cardiorespiratory fitness for Indigenous populations should be considered a primary health strategy.

Insulin sensitivity is reduced in children with high body-fat regardless of BMI

PURPOSE

To examine the association between insulin sensitivity and adiposity in children stratified according to their body mass index (BMI: normal weight, NW; overweight or obese, OW/OB) and body-fat percentage (BF%: adipose or NonAdipose), and determine whether cardiorespiratory fitness (CRF) ameliorates any deleterious associations.

METHODS

This prospective cohort study comprises a cross-sectional and longitudinal analyses of data collected at baseline and 2 years later on children (7.7-13.4 years) attending public school in Denmark. Levels of CRF were measured using the Andersen test, whereas BF% was measured by dual-energy X-ray absorptiometry (DXA). Fasting plasma glucose and insulin concentrations were measured and the homoeostatic model assessment of insulin resistance (HOMA-IR) used to assess insulin sensitivity.

RESULTS

Approximately 8% of children classified as normal weight by BMI had high BF% (NW + Adipose). Children with high BF% had significantly higher insulin (NW + adipose: 32.3%; OW/OB + Adipose: 52.2%) and HOMA-IR scores (NW + Adipose: 32.3%; OW/OB + Adipose: 55.3%) than children classified as NW without high BF% (reference group; NW + NonAdipose). Adjusting for CRF reduced this difference, but did not completely ameliorate these associations. Longitudinally, children with high BF% (OW/OB + Adipose or NW + Adipose) had significantly worse insulin sensitivity 2 years later than NW + NonAdipose children (All p < 0.001). The few children (n = 14) who improved their BMI or BF% during the 2 years follow-up, no longer had significantly worse insulin sensitivity than children with NW + NonAdipose.

CONCLUSION

High BF% in children is associated with significantly lower insulin sensitivity even when BMI is considered NW. Longitudinally, insulin sensitivity is lower in children with high BF% with or without high BMI. The CRF was a significant covariate in these models, but CRF did not completely ameliorate the effects of high BF% on insulin sensitivity.

Cardiorespiratory fitness, fatness and incident diabetes

AIMS

Increases in prevalence have led to a diabetes pandemic. Obesity and low cardiorespiratory fitness (CRF) are considered to be central mechanisms. We investigated if the effect of CRF on diabetes risk was equivalent across levels of fatness among healthy men.

METHODS

In total 4988 middle-aged Caucasian employed men free of cardiovascular disease, diabetes and cancer were included from the Copenhagen Male Study starting in 1970-71. CRF was assessed using a sub-maximal bicycle ergometer test and body mass index (BMI) was measured by height and weight. Their interaction and stratified associations with diabetes incidence were estimated in multivariable Cox-models including conventional risk factors and social class. Diabetes incidence was assessed through a national register.

RESULTS

During 44 years of follow-up, 518 (10.4%) incident cases of diabetes occurred. In the multi-adjusted model, the obese had a significantly higher risk of diabetes compared to normal weight men (Hazard Ratio (HR):4.89; 95% CI: 3.62-6.61) and CRF was significantly inversely associated with diabetes (HR:0.86; 95% CI: 0.75-0.98 per 10-unit increase in ml/kg/min¹ CRF). A significant multi-adjusted interaction between CRF, BMI and diabetes was found (p=0.009). The stratified multi-adjusted analyses on BMI showed a significantly stronger reduced risk of diabetes per 10-unit increase in ml/kg/min¹ of CRF among the obese (HR:0.58; CI: 0.38-0.89), but a weaker association among overweight (HR:0.86; CI: 0.71-1.03) and normal weight (HR:0.97; CI: 0.76-1.23).

CONCLUSION

High CRF has a stronger protective effect on diabetes among obese than among normal weight men, supporting the recommendation of fitness-enhancing physical activity for preventing diabetes among the obese.

Cardiorespiratory Fitness and Incidence of Type 2 Diabetes in United States Veterans on Statin Therapy

BACKGROUND

Impact of cardiorespiratory fitness on statin-related incidence of type 2 diabetes has not been assessed. We assessed the cardiorespiratory fitness and diabetes incidence association in dyslipidemic patients on statins.

METHODS

We identified dyslipidemic patients with a normal exercise test performed during 1986 and 2014 at the Veterans Affairs Medical Centers in Washington, DC or Palo Alto, Calif. The statin-treated patients (n = 4092; age = 58.8 ± 10.9 years) consisted of 2701 Blacks and 1391 Whites. None had evidence of type 2 diabetes prior to statin therapy. We formed 4 fitness categories based on age and peak metabolic equivalents achieved: Least-fit (n = 954), Low-fit (n = 1201), Moderate-fit (n = 1242), and High-fit (n = 695). The non-statin-treated cohort (n = 3001; age = 57.2 ± 11.2 years) with no evidence of type 2 diabetes prior to the exercise test served as controls.

RESULTS

Diabetes incidence was 24% higher in statin-treated compared with non-statin-treated patients (P <.001). In the statin-treated cohort, 1075 (26.3%) developed diabetes (average annual incidence rate of 30.6 events/1000 person-years). Compared with the Least-fit, adjusted risk decreased progressively with increasing fitness and was 34% lower for High-fit patients (hazard ratio [HR] 0.66; 95% confidence interval [CI], 0.53-0.82; P <.001). Compared with the nonstatin cohort, elevated risk was evident only in the Least-fit (HR 1.50; 95% CI, 1.30-1.73; P <.001) and Low-fit patients (HR 1.22; 95% CI, 1.06-1.41; P = .006).

CONCLUSIONS

Risk of diabetes in statin-treated dyslipidemic patients was inversely and independently associated with cardiorespiratory fitness. The increased risk was evident only in relatively low-fitness patients. Improving fitness may modulate the potential diabetogenic effects of statins.

Relation of Exercise Capacity to Risk of Development of Diabetes in Patients on Statin Therapy (the Henry Ford Exercise Testing Project)

High exercise capacity (EC) has been associated with a lower risk of incident diabetes, whereas statin therapy has been associated with a higher risk. We sought to investigate whether the association between EC and diabetes risk is modified by statin therapy. This retrospective cohort study included 47,337 patients without diabetes or coronary artery disease at baseline (age 53 ± 13 years, 48% women, 66% white) who underwent clinical treadmill stress testing within the Henry Ford Health System from January 1, 1991, to May 31, 2009. The patients were stratified by baseline statin use and estimated peak METs achieved during exercise testing. Hazard ratios for incident diabetes were calculated using Cox proportional hazards models adjusted for demographic characteristics, co-morbidities, pertinent medications, and stress test indication. We observed 6,921 new diabetes cases (14.6%) over a median follow-up period of 5.1 years (interquartile interval of 2.6 to 8.2 years). Compared with the statin group, the no-statin group achieved higher mean METs (8.9 ± 2.7 vs 9.6 ± 3.0, respectively; p <0.001). After adjustment for covariates, a higher EC was associated with a lower risk of incident diabetes, irrespective of statin use (p-interaction = 0.15). Each 1-MET increment was associated with an 8%, 8%, and 6% relative risk reduction in the total cohort, the no-statin, and the statin groups, respectively (95% confidence interval, 0.91 to 0.93, 0.91 to 0.93, and 0.91 to 0.96, respectively; p <0.001 for all). We conclude that a higher EC is associated with a lower risk of incident diabetes regardless of statin use.

Prevalence and Associated Characteristics of Metabolically Healthy Obese Phenotypes in a Community Dwelling Population

Background

Recent research has focused on overweight and obese individuals with healthy metabolic profiles. Metabolically healthy and obese (MHO) individuals may have unique characteristics, compared to metabolically unhealthy obese (MUO) individuals. The purpose of this study was to evaluate the prevalence and clinical characteristics of both MHO and metabolically unhealthy normal-weight (MUNW) phenotypes in a community dwelling population.

Methods

Data from women (n=1,916) and men (n=867) aged 20 to 73 years who participated in the Health Examination of Nowon Health Care Center were analyzed. Subjects were categorized according to the presence, absence, or combination of metabolic syndrome and Asian-specific body mass index (BMI) criteria for overweight and obesity.

Results

The proportions of metabolic healthy individuals in the overweight and obese categories were 67% (overweight) and 39% (obese), respectively. The prevalence rate of the MUNW was 12% of normal weight individuals. Within the overweight and obese categories, MHO individuals tended to be younger compared with their MUO counterparts. High waist circumference (WC) and low high-density lipoprotein cholesterol (HDL-C)levels were two of the most common metabolic risk factors observed in the metabolically unhealthy group.

Conclusion

The prevalence of both MHO and MUNW phenotypes is relatively high in this community-dwelling population. There is an urgent need for the implementation of lifestyle intervention, consisting of regular exercise and healthy eating in the Nowon Health Care Center.

Does fitness improve the cardiovascular risk profile in obese subjects?

BACKGROUND AND AIMS

Good cardiorespiratory fitness has been suggested to reduce the risk of cardiovascular disease in obesity. We explored the association of fitness with the prevalences of major cardiovascular risk factor like hypertension (HT), diabetes and metabolic syndrome (MetS) in overweight and obese subjects.

METHODS AND RESULTS

Clinical data from 491 participants in the FAT associated CardiOvasculaR dysfunction (FATCOR) study were analyzed. Physical fitness was assessed by ergospirometry, and subjects with at least good level of performance for age and sex were classified as fit. HT subtypes were identified from clinic and 24-h ambulatory blood pressure in combination. Diabetes was diagnosed by oral glucose tolerance test. MetS was defined by the American Heart Association and National Heart, Lung and Blood Institute criteria. The participants were on average 48 years old (60% women), and mean body mass index (BMI) was 32 kg/m². 28% of study participants were classified as fit. Fitness was not associated with lower prevalences of HT or HT subtypes, diabetes, MetS or individual MetS components (all p > 0.05). In multivariable regression analysis, being fit was characterized by lower waist circumference, BMI < 30 kg/m², non-smoking and a higher muscle mass (all p < 0.05).

CONCLUSION

In the FATCOR population, fitness was not associated with a lower prevalence of major cardiovascular risk factors like HT, diabetes or MetS. Given the strong association of cardiovascular risk factor burden with risk of clinical cardiovascular disease, these findings challenge the notion that fitness alone is associated with lower risk of cardiovascular disease in obesity.

Combined Association of Cardiorespiratory Fitness and Body Fatness With Cardiometabolic Risk Factors in Older Norwegian Adults: The Generation 100 Study

Objective

To investigate the independent and combined associations of fitness and fatness with cardiometabolic risk factors in older Norwegian women and men.

Patients and Methods

We conducted a cross-sectional study of 505 women and 417 men aged 70 to 77 years enrolled in the Generation 100 study in Norway. Fitness was assessed as peak oxygen uptake and fatness as high body mass index (BMI; ≥25 kg/m²), waist circumference (WC) of 88 cm or greater for women and 102 cm or greater for men, and percent body fat (%BF) of 35% or greater and 25% or greater for women and men, respectively. High cardiometabolic risk was defined as the presence of 2 or more of the following risk factors: elevated triglyceride level, reduced high-density lipoprotein cholesterol concentration, elevated blood pressure, and elevated fasting glucose level or pharmacological treatment of these conditions.

Results

Receiver operating characteristic curve analyses identified fitness levels of less than 25.7 and less than 30.7 mL/kg per minute in women and men, respectively, as critical thresholds for having high cardiometabolic risk. Individuals with levels below these thresholds had an adjusted odds ratio of 2.77 (95% CI, 2.09-3.66) for having high cardiometabolic risk, while high BMI, WC, and %BF had odds ratios (95% CIs) of 3.58 (2.69-4.77), 3.06 (2.29-4.10), and 3.26 (2.47-4.30), respectively. In our combined analyses, being lean did not attenuate the cardiometabolic risk associated with low fitness, and combinations of low fitness and/or high BMI, WC, or %BF cumulatively increased cardiometabolic risk.

Conclusion

Low fitness and indication of fatness were independently and cumulatively associated with poor cardiometabolic health. Our results emphasize the importance of including both physical fitness and body fatness in the assessment of cardiometabolic risk and health promotion efforts in older adults.

Pre-diabetes tsunami: incidence rates and risk factors of pre-diabetes and its different phenotypes over 9 years of follow-up

AIMS

To investigate the incidence of pre-diabetes and its different phenotypes and the related risk factors during 9 years of follow-up.

METHODS

A total of 5879 people (2597 men and 3282 women) aged ≥ 20 years, free of diabetes and pre-diabetes, took part in the study. Multivariable Cox proportional hazard models were used to evaluate hazard ratios (HR) and 95% confidence intervals (CI) for all potential risk factors.

RESULTS

Overall, 853 men and 902 women developed pre-diabetes. Incidence rates of pre-diabetes were 46.1 per 1000 person-years in men and 36.8 per 1000 person-years in women, while isolated impaired fasting glucose had the highest incidence rate among all pre-diabetes phenotypes. In both sexes, age, family history of diabetes, fasting plasma glucose and 2-hour post-challenge plasma glucose were related to incident pre-diabetes. Among women, waist-to-height ratio [HR: 1.02 (1.00-1.03)] and being divorced/widowed compared with married [HR: 0.67 (0.52-0.87)] were significant predictors of pre-diabetes; whereas among men, community-based intervention [HR: 0.79 (0.68-0.90)], higher level of education and being single [HR: 0.77 (0.6-0.97)] were protective against progression to pre-diabetes. Moreover, hip circumference among women [HR: 0.95 (0.93-0.98)] and current smoking among men [HR: 1.69 (1.15-2.48)] were related to incident combined impaired fasting glucose and impaired glucose tolerance.

CONCLUSION

More than 4% of the Iranian population develop pre-diabetes each year, emphasizing the important role of socio-economic factors (marital status, education and smoking habits) and community-based intervention in progression to impaired glucose regulations. Thus, emergent intervention is necessary to halt the tsunami of pre-diabetes among the Iranian population.