Thigh circumference and risk of heart disease and premature death: prospective cohort study

Thigh circumference and low ankle brachial index in US adults: results from the National Health and Nutrition Examination Survey 1999-2004

OBJECTIVE

Recent studies have suggested that smaller thighs are a disadvantage for health and survival, but the association of thigh circumference with atherosclerosis remains uncertain. The purpose of this study was to investigate the association between thigh circumference and peripheral arterial disease (PAD), as measured by ankle brachial index (ABI).

METHODS

This study used data from the National Health and Nutrition Examination Survey (1999-2004), in which participants' ABI and thigh circumference were measured simultaneously. A total of 5716 participants (2959 men and 2757 women) were included in the final analysis. A diagnosis of PAD was determined on the basis of ABI <0.9.

RESULTS

The overall prevalence of PAD in this sample was 6.6%. Thigh circumference of those with PAD was 50.1cm compared to 52.2 cm for those without PAD (p < 0.0001). After adjusting for potential covariates, the prevalence of PAD generally decreased as thigh circumference increased up to 55 cm. In the first quantile (smallest thigh circumference), men and women had as much as a 4.8-fold (95% CI, 2.28-10.29) and a 3-fold (95% CI, 1.45-6.18) increased risk of PAD, respectively. Above 55 cm, PAD was no longer related to thigh circumference.

CONCLUSIONS

Small thigh circumference may be associated with PAD, as measured by ABI.

A new body shape index predicts mortality hazard independently of body mass index

Background

Obesity, typically quantified in terms of Body Mass Index (BMI) exceeding threshold values, is considered a leading cause of premature death worldwide. For given body size (BMI), it is recognized that risk is also affected by body shape, particularly as a marker of abdominal fat deposits. Waist circumference (WC) is used as a risk indicator supplementary to BMI, but the high correlation of WC with BMI makes it hard to isolate the added value of WC.

Methods and Findings

We considered a USA population sample of 14,105 non-pregnant adults () from the National Health and Nutrition Examination Survey (NHANES) 1999–2004 with follow-up for mortality averaging 5 yr (828 deaths). We developed A Body Shape Index (ABSI) based on WC adjusted for height and weight:

ABSI had little correlation with height, weight, or BMI. Death rates increased approximately exponentially with above average baseline ABSI (overall regression coefficient of per standard deviation of ABSI [95% confidence interval: –]), whereas elevated death rates were found for both high and low values of BMI and WC. (–) of the population mortality hazard was attributable to high ABSI, compared to (–) for BMI and (–) for WC. The association of death rate with ABSI held even when adjusted for other known risk factors including smoking, diabetes, blood pressure, and serum cholesterol. ABSI correlation with mortality hazard held across the range of age, sex, and BMI, and for both white and black ethnicities (but not for Mexican ethnicity), and was not weakened by excluding deaths from the first 3 yr of follow-up.

Conclusions

Body shape, as measured by ABSI, appears to be a substantial risk factor for premature mortality in the general population derivable from basic clinical measurements. ABSI expresses the excess risk from high WC in a convenient form that is complementary to BMI and to other known risk factors.

Association between thigh muscle development and the metabolic syndrome in adults

BACKGROUND

Previous research has demonstrated an association between the metabolic syndrome (MS) and muscle mass; however, no studies have shown any relationship with a particular segment of the body, which would be more useful in clinical settings.

AIMS

To investigate the association between muscle development of different segments of the body and presence of the MS in adults.

METHODS

We used fractionation of body mass to calculate the development of muscle mass and correlated this with presence of the MS in a cross-sectional study in adults.

RESULTS

The mean age and body mass index were 42.7 ± 6.6 years and 25.3 ± 3.7 kg/m(2), respectively. 23.1% of adults suffered from the MS. After adjusting for multiple variables, the Z score of both thigh and chest muscle girths were significantly associated with the MS. There were significant differences between adults with or without the MS in the Z score of thigh [-0.686; 95% confidence interval (95% CI) -1.020 to -0.351], mid-thigh (-0.566; 95% CI -0.931 to -0.200) and chest (0.611; 95% CI 0.260-0.962) girths.

CONCLUSIONS

There is an association between muscle development and the MS; moreover, muscle thigh perimeter was larger in those without the MS. The use of muscle development of the thigh as an indicator of cardiovascular health-related metabolic alterations is proposed.

The association of insulin resistance and carotid atherosclerosis with thigh and calf circumference in patients with type 2 diabetes

Background

The relationship between body composition parameters such as thigh and calf circumference and insulin resistance or atherosclerosis in type 2 diabetes is poorly understood. The aim of this study was to investigate the relationship between insulin resistance, atherosclerosis, and thigh and calf circumference in patients with type 2 diabetes.

Methods

A total of 4,427 subjects with type 2 diabetes were enrolled in this study. Insulin sensitivity was assessed according the rate constant for plasma glucose disappearance (Kitt) determined via the short insulin tolerance test. Biochemical and anthropometric profiles were measured according to a standardized protocol. Visceral fat thickness and carotid intima media thickness (IMT) were measured by ultrasonography.

Results

Insulin sensitivity index (Kitt) was significantly correlated with weight adjusted thigh and calf circumference. Thigh circumference was inversely associated with IMT in men and women and calf circumference was negatively correlated with IMT in women. Multiple stepwise regression analysis revealed that thigh circumference was independently correlated with insulin sensitivity index (Kitt) and IMT. Furthermore, in multivariate logistic regression analysis, thigh circumference was an independent determinant factor for carotid atherosclerosis in patients with type 2 diabetes even after adjusting for other cardiovascular risk factors.

Conclusions

Thigh and calf circumference were correlated with insulin resistance and carotid atherosclerosis, and thigh circumference was independently associated with insulin resistance and carotid atherosclerosis in patients with type 2 diabetes.

Low-intensity exercise can increase muscle mass and strength proportionally to enhanced metabolic stress under ischemic conditions

Skeletal muscle bulk and strength are becoming important therapeutic targets in medicine. To increase muscle mass, however, intensive, long-term mechanical stress must be applied to the muscles, and such stress is often accompanied by orthopedic and cardiovascular problems. We examined the effects of circulatory occlusion in resistance training combined with a very low-intensity mechanical load on enhancing muscular metabolic stress and thereby increasing muscle bulk. Muscular metabolic stress, as indicated by the increases in inorganic phosphate (P(i)) and a decrease in intramuscular pH, was evaluated by (31)P-magnetic resonance spectroscopy during unilateral plantar-flexion at 20% of the one-repetition maximum (1-RM) with circulatory occlusion for 2 min in 14 healthy, male untrained participants (22 yr) at baseline. Participants performed two sets of the same exercise with a 30-s rest between sets, 2 times/day, 3 days/wk, for 4 wk. The muscle cross-sectional area (MCA) of the plantar-flexors and the 1-RM were measured at baseline and after 2 and 4 wk of training. MCA and 1-RM were significantly increased after 2 and 4 wk (P < 0.05, respectively). The increase in MCA at 2 wk was significantly (P < 0.05) correlated with the changes in P(i) (r = 0.876) and intramuscular pH (r = 0.601). Furthermore, the increases in MCA at 4 wk and 1-RM at 2 wk were also correlated with the metabolic stress. Thus enhanced metabolic stress in exercising muscle is a key mechanism for favorable effects by resistance training. Low-intensity resistance exercise provides successful outcomes when performed with circulatory occlusion, even with a short training period.

Body configuration as a predictor of mortality: comparison of five anthropometric measures in a 12 year follow-up of the Norwegian HUNT 2 study

BACKGROUND

Distribution of body fat is more important than the amount of fat as a prognostic factor for life expectancy. Despite that, body mass index (BMI) still holds its status as the most used indicator of obesity in clinical work.

METHODS

We assessed the association of five different anthropometric measures with mortality in general and cardiovascular disease (CVD) mortality in particular using Cox proportional hazards models. Predictive properties were compared by computing integrated discrimination improvement and net reclassification improvement for two different prediction models. The measures studied were BMI, waist circumference, hip circumference, waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR). The study population was a prospective cohort of 62,223 Norwegians, age 20-79, followed up for mortality from 1995-1997 to the end of 2008 (mean follow-up 12.0 years) in the Nord-Trøndelag Health Study (HUNT 2).

RESULTS

After adjusting for age, smoking and physical activity WHR and WHtR were found to be the strongest predictors of death. Hazard ratios (HRs) for CVD mortality per increase in WHR of one standard deviation were 1.23 for men and 1.27 for women. For WHtR, these HRs were 1.24 for men and 1.23 for women. WHR offered the greatest integrated discrimination improvement to the prediction models studied, followed by WHtR and waist circumference. Hip circumference was in strong inverse association with mortality when adjusting for waist circumference. In all analyses, BMI had weaker association with mortality than three of the other four measures studied.

CONCLUSIONS

Our study adds further knowledge to the evidence that BMI is not the most appropriate measure of obesity in everyday clinical practice. WHR can reliably be measured and is as easy to calculate as BMI and is currently better documented than WHtR. It appears reasonable to recommend WHR as the primary measure of body composition and obesity.

Ratio of waist-to-calf circumference and carotid atherosclerosis in Korean patients with type 2 diabetes

OBJECTIVE

To investigate whether waist circumference (WC), calf circumference (CC), and waist-to-calf ratio (WCR) are associated with carotid atherosclerosis in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was an observational study performed in 3,694 Korean patients with type 2 diabetes. Anthropometric measures and carotid ultrasound were performed on each subject. Carotid atherosclerosis was defined as having a clearly isolated focal plaque or mean carotid intima-media thickness (CIMT) ≥1.1 mm.

RESULTS

CIMT and the frequency of carotid atherosclerosis were higher with increasing WC quartiles and decreasing CC quartiles. There was an augmentative effect of CC and WC on the frequency of carotid atherosclerosis, which was dramatically higher in both the highest WC quartile and lowest CC quartile. However, except for the relationship between the quartile of CC with the frequency of carotid atherosclerosis in men, those associations disappeared after adjusting for potential confounders. In contrast, WCR was significantly related to CIMT (only in women) and carotid atherosclerosis, even after adjustment (adjusted odds ratio for carotid atherosclerosis for the highest quartile of WCR compared with the lowest quartile being 1.178 [95% CI 1.026-1.353] and 1.276 [1.053-1.545] in men and women, respectively).

CONCLUSIONS

A low CC and high WC seems to be associated with a carotid atherosclerotic burden in Korean diabetic patients. In particular, compared with each circumference, WCR is independently associated with carotid atherosclerosis. However, the cross-sectional nature of the study limits conclusions regarding the direction or causality. Further longitudinal study is warranted in this and other ethnic groups.

Body composition and coronary heart disease mortality--an obesity or a lean paradox?

OBJECTIVE

To determine the combined effects of body mass index (BMI) and body fat (BF) on prognosis in coronary heart disease (CHD) to better understand the obesity paradox.

PATIENTS AND METHODS

We studied 581 patients with CHD between January 1, 2000, and July 31, 2005, who were divided into low (<25) and high BMI (≥25), as well as low (≤25% men and ≤35% women) and high BF (>25% in men and >35% in women). Four groups were analyzed by total mortality during the 3-year follow-up by National Death Index: low BF/low BMI (n=119), high BF/low BMI (n=26), low BF/high BMI (n=125), and high BF/high BMI (n=311).

RESULTS

During the 3-year follow-up, mortality was highest in the low BF/low BMI group (11%), which was significantly (P<.001) higher than that in the other 3 groups (3.9%, 3.2%, and 2.6%, respectively); using the high BF/high BMI group as a reference, the low BF/low BMI group had a 4.24-fold increase in mortality (confidence interval [CI], 1.76-10.23; P=.001). In multivariate logistic regression for mortality, when entered individually, both high BMI (odds ratio [OR], 0.79; CI, 0.69-0.90) and high BF (OR, 0.89; CI, 0.82-0.95) as continuous variables were independent predictors of better survival, whereas low BMI (OR, 3.60; CI, 1.37-9.47) and low BF (OR, 3.52; CI, 1.34-9.23) as categorical variables were independent predictors of higher mortality.

CONCLUSION

Although both low BF and low BMI are independent predictors of mortality in patients with CHD, only patients with combined low BF/low BMI appear to be at particularly high risk of mortality during follow-up. Studies are needed to determine optimal body composition in the secondary prevention of CHD.

A simple ultrasound correlate of visceral fat

The roles of body fat and muscle masses for developing cardiometabolic disorders are opposed to each other. The aim of this study was to analyze whether abdominal visceral to thigh muscle thickness ratio (AVTMR) measured by ultrasonography can be a simple yet useful index assessing the disproportion between visceral fat and thigh muscle, and whether it is associated with carotid atherosclerosis. This was an observational study performed on 15 healthy men and 68 men with newly-diagnosed type 2 diabetes. Using ultrasonography, abdominal visceral thickness, mid-thigh muscle thickness and carotid artery intima-media thickness (CA-IMT) were determined. The visceral fat amount and lipid-rich muscle mass were increased and metabolic profile was poorer across AVTMR tertiles. The AVTMR was associated an increased CA-IMT independent of traditional risk factors. The AVTMR measure using ultrasonography might be a relevant index identifying individuals at an increased risk of cardiovascular disease.

Thigh circumference as a useful predictor of body fat in adolescent girls with anorexia nervosa

BACKGROUND/AIM

Girls with anorexia nervosa (AN) demonstrate severe depletion of body fat. The aim of this study was to determine an accurate anthropometric measurement for clinical assessment of fat depletion in girls with AN in connection with body composition measured by dual-energy X-ray absorptiometry (DXA).

METHODS

In 64 female AN patients aged 12.8-23.1 years (mean 16.0 ± 1.8), body mass index (BMI), skinfold thickness (subscapular, abdominal and triceps), mid-upper arm and thigh circumference, fat mass (FM) and lean mass were determined and compared with the data of 71 controls.

RESULTS

Girls with AN had lower anthropometric traits and were fat depleted compared to controls (14.9 ± 7.3 vs. 27.4 ± 6.4% of FM using DXA; all p < 0.001). BMI, thigh circumference and subscapular skinfold thickness demonstrated a very similar predictive value for DXA assessment of body fat. Based on the receiver-operating characteristic curve analysis and the determination of the positive predictive value, thigh circumference appeared the most specific and sensitive anthropometric predictor of fatness discriminating between AN and healthy girls, with the AUC value reaching 0.95 (95% CI = 0.92-0.97). Using a cutoff value of 49.6 cm, accuracy was 90.6%, sensitivity 93% and specificity 88.7%.

CONCLUSIONS

Thigh circumference strongly correlates with DXA-FM and demonstrates a slight clinical advantage over BMI. This simple measurement might also serve as a useful predictor of body fatness in adolescent girls with AN and should therefore be further evaluated in independent cohort studies.

Hip Hip Hurrah! Hip size inversely related to heart disease and total mortality

During the past decade a series of published reports have examined the value of studying the relation between hip circumferences and cardiovascular end points. Specifically, in a series of recent studies the independent effects of hip circumference have been studied after adjustment for general obesity and/or waist circumference. These studies have been remarkable in terms of their consistency, and in the unexpected finding of an adverse effect of small hip size, after statistically correcting for differences in general and abdominal size. The hazard related to a small hip size may be stronger for women than men, but is evident in both genders. In this 'viewpoint', we wish to draw attention to the emerging body of evidence and to encourage researchers to continue collecting measures of lower body size in their surveys.

Muscles and their myokines

In the past, the role of physical activity as a life-style modulating factor has been considered as that of a tool to balance energy intake. Although it is important to avoid obesity, physical inactivity should be discussed in a much broader context. There is accumulating epidemiological evidence that a physically active life plays an independent role in the protection against type 2 diabetes, cardiovascular diseases, cancer, dementia and even depression. For most of the last century, researchers sought a link between muscle contraction and humoral changes in the form of an 'exercise factor', which could be released from skeletal muscle during contraction and mediate some of the exercise-induced metabolic changes in other organs such as the liver and the adipose tissue. We have suggested that cytokines or other peptides that are produced, expressed and released by muscle fibres and exert autocrine, paracrine or endocrine effects should be classified as 'myokines'. Given that skeletal muscle is the largest organ in the human body, our discovery that contracting skeletal muscle secretes proteins sets a novel paradigm: skeletal muscle is an endocrine organ producing and releasing myokines, which work in a hormone-like fashion, exerting specific endocrine effects on other organs. Other myokines work via paracrine mechanisms, exerting local effects on signalling pathways involved in muscle metabolism. It has been suggested that myokines may contribute to exercise-induced protection against several chronic diseases.

Insulin resistance in the middle-aged women with "Tigerish Back and Bearish Waist"

The objective of this study was to elucidate the role of fat distribution in predicting insulin resistance in peri- or post-menopausal women. The results demonstrated that insulin resistance increases with waist circumference and subscapular skinfold thickness but decreases with higher thigh circumflex in the peri- and post-menopausal women.

Coronary heart disease and body fat distribution

Larger waist circumference or waist-hip ratio, as crude indicators of visceral fat mass, are associated with adverse metabolic profile, but their role in predicting future coronary heart disease (CHD) events has been less investigated. Recent epidemiologic findings suggest that these simple and inexpensive measures of abdominal fat distribution predict CHD independently of body mass index, and, to a certain extent, cardiovascular disease risk factors. The magnitude and shape of the association between abdominal adiposity and CHD have been shown to vary with age, gender, and ethnicity. Studies have also suggested that lower body fat is associated with reduced CHD risk, although the clinical relevance for this finding needs further elucidation. Assessing body fat distribution may be useful for improving CHD risk assessment, although more studies are needed to assess consistency in CHD risk predictions across populations. A consensus is also needed to define the clinically relevant cut-off points for waist circumference or waist-hip ratio.

Changes in waist circumference and mortality in middle-aged men and women

Background

Waist circumference (WC) adjusted for body mass index (BMI) is positively associated with mortality, but the association with changes in WC is less clear. We investigated the association between changes in WC and mortality in middle-aged men and women, and evaluated the influence from concurrent changes in BMI.

Methodology/Principal Findings

Data on 26,625 healthy men and women from the Danish Diet, Cancer and Health study was analyzed. WC and BMI were assessed in 1993–97 and in 1999–02. Information on mortality was obtained by linkage to the Danish central Person Register. Hazard ratios (HR) were estimated with Cox regression models. During 6.7 years of follow-up, 568 and 361 deaths occurred among men and women, respectively. Changes in WC were positively associated with mortality (HR per 5 cm for the sexes combined  = 1.09 (1.02∶1.16) with adjustment for covariates, baseline WC, BMI and changes in BMI), whereas changes in BMI were inversely associated with mortality (HR per kg/m2 for the sexes combined  = 0.91 (0.86, 0.97) with adjustment for covariates, baseline WC, BMI and changes in WC). Associations between changes in WC and mortality were not notably different in sub-groups stratified according to changes in BMI, baseline WC or when smokers or deaths occurring within the first years of follow-up were excluded.

Conclusions/Significance

Changes in WC were positively associated with mortality in healthy middle-aged men and women throughout the range of concurrent changes in BMI. These findings suggest a need for development of prevention and treatment strategies targeted against redistribution of fat mass towards the abdominal region.

Abdominal diameter index and 12-year cardiovascular disease incidence in male bridge and tunnel workers

BACKGROUND

A recent study has suggested that abdominal diameter index (ADI), that is, the supine sagittal abdominal diameter divided by thigh circumference, may be a better measure of the increased risk of abdominal adiposity for prevalent ischemic cardiovascular disease (CVD) than body mass index or waist circumference. The risk associated with all of these measures is believed to arise from the link between visceral obesity and insulin resistance.

METHODS

Male bridge and tunnel workers in New York City without ischemic CVD in the highest and lowest quartiles of ADI (n=218) in a 1993-1994 cross-sectional study of risk factors and prevalent coronary heart disease were administered telephone follow-up questionnaires after 12 years (2005-2006) to assess incident ischemic CVD (new-onset angina, coronary revascularization, myocardial infarction, stroke, peripheral vascular disease and cardiovascular death).

RESULTS

In the univariate analysis of 111 participants able to be contacted, study members in the highest quartile vs the lowest quartile of ADI had a significantly increased cumulative incidence of ischemic CVD (Relative risk (RR)=7.9, P=0.002). In a logistic regression analysis controlling for other cardiovascular risk factors including age, smoking, total cholesterol, high-density lipoprotein cholesterol, triglycerides, blood pressure and glucose, ADI lost statistical significance (RR=4.37, P=0.063), suggesting that ADI may be an anthropometric surrogate for these cardiovascular risk factors.

CONCLUSIONS

ADI is a powerful anthropometric index for 12-year cumulative incidence of ischemic CVD in working men in New York City.

Dose effect on intramuscular metabolic stress during low-intensity resistance exercise with blood flow restriction

Our previous study reported that metabolic stress in skeletal muscle achieved by combining moderate blood flow restriction (BFR) with low-intensity resistance exercise at 20% of one repetition maximum (1 RM) could not reach the level achieved by high-intensity resistance exercise. Since the previous protocol is typical of current regimens of this type, we sought in this study to optimize the exercise protocol for low-intensity resistance exercise with BFR by examining the dose effects of exercise intensity and pressure. Twelve healthy subjects participated in this study. They were asked to perform unilateral plantar flexion for 2 min (30 repetitions/min) under six different conditions: two resistance exercises (20% 1 RM and 65% 1 RM) without BFR, and four BFR protocols. The four BFR protocols included three different exercise intensities (20, 30, and 40% 1 RM) with moderate pressure (MP) using 130% of systolic blood pressure (147+/-17 mmHg, mean+/-SD) and 20% 1 RM with high pressure at 200 mmHg. Intramuscular metabolites and pH were obtained by 31P-magnetic resonance spectroscopy. Significant dose effects on intramuscular metabolites and pH were observed for exercise intensity (P<0.001) but not for BFR pressure. The BFR protocol combining 30% 1 RM with MP had similar results as the high-intensity load at 65% 1 RM. Intramuscular metabolic stress during BFR exercise might be susceptible to increasing exercise intensity. To replace high-intensity resistance exercise, the BFR protocol might require an intensity of >or=30% 1 RM.