Accuracy of body fat percent and adiposity indicators cut off values to detect metabolic risk factors in a sample of Mexican adults

White Blood Cell and C-Reactive Protein Levels Are Similar in Obese Hispanic White Women Reporting Adherence to a Healthy Plant, Unhealthy Plant, or Animal-Based Diet, unlike in Obese Non-Hispanic White Women

While modifying dietary patterns can reduce the effects of inflammation in obesity, less is known about the impact of dietary patterns on inflammation levels in women of different ethnicities. This study investigated the link between dietary patterns and mediators associated with inflammation, such as C-reactive protein (CRP) and white blood cells (WBCs), among obese Hispanic and Non-Hispanic White women. CRP and WBC counts were extracted from the National Health and Nutrition Examination Survey conducted between 2003 and 2010. Based on their recorded responses to two 24 h recall interviews, individuals were grouped into one of three dietary patterns: healthy plant-based, less healthy plant-based, or animal-based. Comparisons were run between obese Hispanic and Non-Hispanic women assigned to the same dietary pattern groups and between dietary pattern groups within ethnic groups. CRP and WBCs increased in obese Non-Hispanics as dietary patterns moved from healthy plant-based to animal-based (pCRP = 0.002 and pWBC = 0.017). Regardless of the dietary pattern, CRP and WBC expression were similar in Hispanic women. In addition, WBCs were higher in Hispanics compared to Non-Hispanics when both populations adhered to healthy plant and less healthy plant dietary patterns. The results indicate that dietary patterns may influence Hispanics' inflammation differently than Non-Hispanics.

Predictors of Cardiac Autonomic Dysfunction in Obesity-Related Hypertension

INTRODUCTION

Cardiac Autonomic Dysfunction (CAD) is an overlooked cardiovascular risk factor in individuals with obesity-related hypertension. Despite its clinical significance, there is a notable lack of clarity regarding the pathophysiological correlates involved in its onset and progression.

AIM

The present study aimed to identify potential predictors of CAD in obesity-related hypertension.

METHODS

A total of 72 participants (34 men and 38 women) were enrolled. Comprehensive evaluations were conducted, including cardiac autonomic function assessments, body composition estimation and biochemical analysis. Participants were categorized as CAD-positive or CAD-negative based on Ewing's criteria for autonomic dysfunction. Univariate logistic regression analysis was performed to identify potential predictors for CAD. Multivariate logistic regression models were further constructed by adjusting clinically relevant covariates to identify independent predictors of CAD.

RESULTS

Multivariate logistic regression analysis revealed that resting heart rate (HRrest), (odds ratio, confidence interval: 0.85, 0.78-0.93; p = 0.001) and percentage body fat (BF%), (odds ratio, confidence interval: 0.78, 0.64-0.96; p = 0.018) were significant independent predictors of CAD. Receiver Operating Characteristic curve analysis depicted optimal cut-off values for HRrest and BF% as > 74.1 bpm and > 33.6%, respectively. Multicolinearity analysis showed variance inflation factors (VIF) below the cautionary threshold of 3.

CONCLUSIONS

The HRrest and BF% emerged as significant independent predictors of CAD in obesity-related hypertension. Therapeutic strategies should target HRrest < 74.1 bpm and BF% < 33.6% to mitigate CAD risk in this population. Future trials are required to establish causal relationships and may consider additional confounding variables in obesity-related hypertension.

A New Approach Using BMI and FMI as Predictors of Cardio-Vascular Risk Factors among Mexican Young Adults

The study aimed to identify accurate cut-off points for waist circumference (WC), body fat percentage (BF%), body mass index (BMI), fat mass index (FMI), and fat-free mass index (FFMI), and to determine their effective accuracy to predict cardiovascular risk factors (CVRFs) among Mexican young adults. A cross-sectional study was conducted among 1730 Mexican young adults. Adiposity measures and CVRFs were assessed under fasting conditions. The optimal cut-off points were assessed using the receiver operating characteristic curve (ROC). Age-adjusted odds ratios (OR) were used to assess the associations between anthropometric measurements and CVRFs. The cut-off values found, in females and males, respectively, for high WC (≥72.3 and ≥84.9), high BF% (≥30 and ≥22.6), high BMI (≥23.7 and ≥24.4), high FMI (≥7.1 and ≥5.5), and low FFMI (≤16 and ≤18.9) differ from those set by current guidelines. High BMI in women, and high FMI in men, assessed by the 50th percentile, had the best discriminatory power in detecting CVRFs, especially high triglycerides (OR: 3.07, CI: 2.21-4.27 and OR: 3.05, CI: 2.28-4.08, respectively). Therefore, these results suggest that BMI and FMI measures should be used to improve the screening of CVRFs in Mexican young adults.

Performance of Body Fat Percentage, Fat Mass Index and Body Mass Index for Detecting Cardiometabolic Outcomes in Brazilian Adults

Obesity is a recognized risk factor for the development of cardiometabolic outcomes. Therefore, it is essential to evaluate anthropometric and body composition indicators used for its diagnosis. This study aimed to assess the diagnostic performance of body fat percentage (BF%), fat mass index (FMI) and body mass index (BMI) for detecting cardiometabolic outcomes in adults. A cross-sectional study was conducted involving adults at 30 years of age from Pelotas, RS (n = 3517) and at 37-39 years from Ribeirão Preto, SP (n = 1696). Receiver operating characteristic (ROC) curves were used to determine the cut-off points for predicting cardiometabolic risk factors, including altered blood pressure, blood glucose, triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDDL-c), C-reactive protein and glycated hemoglobin. The cut-off points of BF% ranged from 25.2 to 27.8 in men and from 37.4 to 39.7 in women at 30 years, and from 26.1 to 27.8 in men and from 38.5 to 42.2 in women at 37-39 years. For FMI (kg/m2), the cut-off points ranged from 6.3 to 7.5 in men and from 9.5 to 10.8 in women at 30 years, and from 7.3 to 7.8 in men and from 10.2 to 12.2 in women at 37-39 years. The BMI cut-off points (kg/m2) ranged from 26.3 to 27.3 in men and from 25.4 to 27.2 in women at 30 years, and from 28.3 to 29.0 in men and from 27.2 to 29.6 in women at 37-39 years. The areas under the curve were similar for the three indicators, ranging from 0.523 to 0.746. BMI showed a performance similar to that of the body fat-based indicators in identifying cardiometabolic outcomes. The cut-off points of the three indicators showed acceptable discriminatory power in subjects with cardiometabolic risk factors.

Sex differences in overweight and obesity among Mexican Americans in the National Health and Nutrition Examination Survey: A comparison of measures

The increasing prevalence of overweight and obesity in the United States, and disparities by race, ethnicity, and gender, have caused concern among public health practitioners, health care providers, and others, in part because overweight and obesity may be linked to chronic health problems and weight stigma. Researchers have traditionally relied upon body mass index (BMI) as a measure of overweight and obesity, despite its limitations. In this study we apply an intersectional framework and use data from the 2011-2018 waves of the nationally representative National Health and Nutrition Examination Survey (NHANES) to study sex differences in the risk of overweight and obesity among Mexican Americans, triangulating three measures that proxy for overweight and obesity: BMI, high waist circumference, and high percent body fat. We assess heterogeneity across nativity, education, income by parenthood status, food security, time in the United States (for immigrants), and receipt of SNAP/WIC benefits (for the low-income sample). Results from logistic regression models indicate choice of cutoff values and measure are critical to determining whether sex disparities exist. We find no evidence of disparities in BMI but evidence of greater risk for females using traditional cutoff values for high waist circumference and high percent body fat. Adjusted cutoff values provide differing results. Minimal heterogeneity is seen. Results reinforce the importance of considering sex disparities and emphasize the importance of critically examining measures that proxy for overweight and obesity risk, given the high stakes surrounding weight stigma.

Analysis on the Change of College Students' Life Pattern and its Impact during the COVID-19 Outbreak in China

Objectives: Our objective was to analyze changes in lifestyle patterns of Chinese college students at home during the COVID-19 outbreak. Methods: According to a structured online questionnaire covering socio- demographic information, anthropometric data, and changes in food intake, physical activity, and sleep during the COVID-19 outbreak, the relationships between the above data before and during the outbreak were analyzed. Results: Among the 781 participants, 38.5% had significantly increased their total food intake and 29.1% had significantly decreased their physical activity. Overall, 44% of participants reported weight gain. The average weight gain was 0.7±2.5 kg. The main causes of weight gain were increased food intake (p < .001), decreased physical activity (p < .01), and an excessive increase or reduction in sleep duration (p < .024). Conclusion: During the COVID-19 outbreak, college students' food intake was found to be increased and physical activity decreased; sleep duration was irregular, and all these factors influenced weight gain.

Characterization of Redox Environment and Tryptophan Catabolism through Kynurenine Pathway in Military Divers’ and Swimmers’ Serum Samples

Endurance and resistance exercises, alone or in combination, induce metabolic changes that affect tryptophan (Trp) catabolism. The kynurenine pathway (KP) is the main route of Trp degradation, and it is modulated by the inflammatory and redox environments. Previous studies have shown that KP metabolites work as myokines that mediate the positive systemic effects related to exercise. However, it is poorly understood how different exercise modalities and intensities impact the KP. The aim of this study was to characterize the effect of two different exercise modalities, military diving and swimming, on the KP and the redox environment. A total of 34 healthy men from the Mexican Navy were included in the study, 20 divers and 14 swimmers, who started and stayed in military training consistently during the six months of the study; 12 Mexican men without fitness training were used as the control group. Physical fitness was determined at the beginning and after 6 months of training; criteria included body composition; serum levels of Trp, kynurenine (KYN), kynurenic acid (KYNA) and 3-hydroxykynurenine (3-HK); the glutathione ratio (GSH/GSSG); and malondialdehyde (MDA).. Results showed a significant loss of body fat in both the diver and swimmer groups. Compared with the control group, divers showed a decrease in Trp and 3-HK levels, but no changes were observed in the KYN/Trp, KYNA/Trp or 3-HK/Trp ratios, while swimmers showed a decrease in KYN levels and an increase in the KYNA and 3-HK levels. Additionally, divers showed a decrease in the GSH/GSSG ratio and an increase in MDA levels, in contrast to the swimmers, who showed a decrease in MDA levels and an increase in GSH/GSSG levels. Our findings suggest a differential shift in the KP and redox environment induced by diving and swimming. Swimming promotes an antioxidant environment and a peripheral overactivation of the KP.

The Correlation of Total Percent Fat With Alterations in Cholesterol and Triglycerides in Adults

Background

To evaluate the detailed relationship between total percent fat (TPF) and cardiovascular disease (CVD)-related lipid biomarkers among adults and find a non-invasive indicator for screening and monitoring of the high CVD risk population.

Methods

Data of 13,160 adults were obtained from the National Health and Examination Survey (NHANES) from 1999 to 2018. TPF was assessed by dual-energy x-ray absorptiometry (DXA), and CVD-related lipid biomarkers included total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Multivariable linear regression models were used to examine associations between TPF with four kinds of lipid biomarkers, and smooth curve fittings and generalized additive models were used to address the non-linear relationship between them. The inflection points were calculated by the recursive algorithm when non-linearities were detected and then weighted two-piecewise linear regression models were constructed.

Results

In multivariable regression, increasing TPF was positively associated with TC, TG, and LDL-C and negatively with HDL-C (all p < 0.001). In addition, the non-linear relationships between them were also identified by generalized additive models and smooth curve fittings. When further stratified TPF by sex, the fitted smooth curves were nearly inverted U-shaped and U-shaped curves, the inflection points were calculated, and the weighted two-piecewise linear regression models were constructed, respectively. The same results existed between android percent fat and these four lipid biomarkers.

Conclusions

Total percent fat was significantly associated with CVD-related lipid biomarkers in adults, positively with TC, TG, and LDL-C and negatively with HDL-C. It could be used as a non-invasive screener and monitor of high CVD risk population when their TPF values were less than the inflection points.

Longitudinal assessment of kidney function in migrant farm workers

Chronic kidney disease of unknown etiology (CKDu) is an epidemic that affects young agricultural workers in several warm regions of the world. However, there is a lack of monitoring of kidney issues in regions with extremely warm environments such as the Northwest of Mexico, a semi-arid region with a growing agricultural industry, where migrant and seasonal farm workers (MSFWs) travel to work in the fields. The objective of this study was to longitudinally assess kidney functioning of MSFWs in relation to pesticide exposure, heat stress and dehydration in a large-scale farm in Mexico. We enrolled 101 MSFWs, of whom 50 were randomly selected to work in an organic certified area and 51 were randomly selected to work in a conventional area. We also enrolled 50 office workers within the same region as a reference group. We collected urine and blood samples from all workers in addition to demographic, behavioral, and occupational characteristics. The physiological strain index (PSI) was used to estimate workers' heat strain. Sampling was conducted at pre-harvest (March) and late in the harvest (July). Linear mixed models were built with the estimated glomerular filtration rate (eGFR) as the dependent variable. We found a significant decrease in kidney function in MSFWs compared to office workers. By the late harvest, one MSFW developed kidney disease, two MSFWs suffered a kidney injury, and 14 MSFWs were at risk of a kidney injury. We found that the eGFR in MSFWs decreased significantly from pre-harvest (125 ± 13.0 mL/min/1.73 m2) to late harvest (109 ± 13.6 mL/min/1.73 m2) (p < 0.001), while no significant change was observed in office workers. The eGFR was significantly lower in MSFWs who worked in the conventional field (101.2 ± 19.4 mL/min/1.73 m2) vs the organic field (110.9 ± 13.6 mL/min/1.73 m2) (p = 0.002). In our final model, we found that dehydration was associated with the decrease of eGFR. We also found an interaction between heat strain and job category, as a significant decline in eGFR by job category (conventional/organic MSFWs and office workers) was related to an increase in heat strain. This suggests that pesticide exposure needs to be considered in combination with heat stress and dehydration. This study provides valuable information on kidney function in MSFWs, and it shows the importance of early long-term monitoring in farm workers in other regions where CKDu has not been evaluated yet.

Comparison of bioelectrical body and visceral fat indices with anthropometric measures and optimal cutoffs in relation to hypertension by age and gender among Chinese adults

Background

Few studies have compared bioelectrical body and visceral fat indices with anthropometric measures, or evaluated their optimal cutoffs in relation to hypertension among Asians. We compared the efficiencies of bioelectrical indices (percentage of body fat, PBF; visceral fat area, VFA) with anthropometric measures (body mass index, BMI; waist-hip ratio, WHR) for hypertension and re-evaluated the optimal cutoffs of each index by age and gender.

Methods

We conducted a cross-sectional survey among 8234 adults for health examination. PBF, VFA, BMI, WHR, and data on hypertension and behaviors were collected. Receiver operating characteristic (ROC) curve and areas under curves (AUCs) were used to analyze the efficiencies of the indices for hypertension, optimal cutoffs were estimated using the Youden index.

Results

A total of 8234 individuals aged 21–91 with median age 44 (interquartile range [IQR] 33–56) years were included and 40.56% were men. The overall prevalence of hypertension was 27.47%. The studied indices were all associated with hypertension in all age-specific groups both among men and women except for WHR in 21–29 years old men and PBF in in 21–29 years old women. Among males, there were no statistical differences in powers of four indices for hypertension in all age-specific groups, except for 40–49 years, in which WHR was better than VFA. Among females, no differences were found among the indices in 30–39 and 70–79 years groups, while WHR was the best in 21–29 years group, VFA was better than PBF in 30–39 and 50–59 years groups, BMI was better than PBF and WHR in 60–69 years group. The optimal cutoffs of PBF, VFA, BMI and WHR ranged from 23.9 to 28.7%, 86.4 to 106.9cm², 23.5 to 27.1 kg/m², 0.92 to 0.96 across the age categories in males, and 32.8 to 36.3%, 75.9 to 130.9cm², 21.9 to 26.4 kg/m², 0.84 to 0.95 across the age categories in females, respectively.

Conclusions

The obesity indices’ efficiencies for hypertension varied by age and gender, and their cutoff values varied across the age categories and gender. Specific indices and cutoffs based on person’s age and gender should be used to identify individuals with hypertension.

Diagnostic performance of body mass index in detection of obesity using different cutoff points for excess body fat

OBJECTIVES

The aim of this study was to assess the diagnostic sensitivity of body mass index (BMI) in detecting obesity according to different cutoff points in order to classify a high body fat percentage (%BF) in adolescents and young adults.

METHODS

This was a cross-sectional study conducted with 2447 adolescents 18 and 19 y of age residing in São Luís, Brazil and 951 young adults 21 to 23 y of age residing in Ribeirão Preto, Brazil. Three references were used to define a high %BF (i.e., those of Williams et al., Ramírez-Vélez et al., and Macias et al.). The area under the receiver operating characteristic area under the curve (AUC) was used to assess the performance of BMI.

RESULTS

Sensitivity ranged from 38.3% to 54.1% among boys and from 12.7% to 72.7% among girls. Among young adults, it ranged from 52.3% to 67.1% in men and from 33.7% to 86.6% in women. The AUC ranged from 0.69 to 0.76 among boys, from 0.56 from 0.85 among girls, from 0.75 to 0.80 among men, and from 0.67 to 0.88 among women. The best cutoff points for the BMI were 24.79 to 25.10 kg/m² for boys, 21.89 to 27.04 kg/m² for girls, 26.43 to 28.22 kg/m² for men, and 23.34 to 29.28 kg/m² for women.

CONCLUSION

The use of different references for the classification of a high %BF implied a difference in the diagnostic sensitivity of the BMI. Higher cutoff points resulted in greater sensitivity and ability to differentiate individuals with and without obesity.

Optimal cut-off values for anthropometric measures of obesity in screening for cardiometabolic disorders in adults

Excessive accumulation of body fat (BF) promotes obesity, whilst posing a significant health hazard. There being no agreed, optimal quantifying methods, application of BF variable in clinical practice is not deemed an effective assessment option. The study, involving 4,735 patients (33.6% men), aged 45-64, aimed to identify optimal cut-off values for anthropometric indicators of obesity to evaluate cardiometabolic risk. A minimum P-value approach was applied to calculate the cut-offs for BF%. Threshold values for body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height (WHTR) ratio, facilitating optimal differentiation of cardiometabolic risk, were based on BF%, expressed as a binary classifier. The newly estimated cut-off values for predicting cardiometabolic risk, based on BMI, were lower than the referential obesity thresholds, whereas the threshold values of WC, WHR, and WHTR were higher. Apart from dyslipidemia, the odds of cardiometabolic disorders were higher, when the anthropometric indicators under study exceeded the cut-off points in both sexes. The proposed cut-offs proved instrumental in predicting cardiometabolic risk, whilst highlighting diagnostic and clinical potential of BF%, whereas BMI boasted the highest predictive potential. Cardiometabolic risk also proved significantly higher even in the overweight patients.

Unique Finite Element Modelling of Human Body Inside Accelerating Car to Predict Accelerations and Frequencies at Different Human Segments

The comfort level of the human occupant inside a dynamic vehicle is dependent on the level of vibration generated inside the different segments of the human body. Some technologies have been developed to provide the final level of vibration inside an automotive-seated human, but those technologies considered only a specific portion of human segments. In the present work, a unique and comprehensive finite element simulation model was proposed to predict the final level of vibration at different segments of a seated human driver inside a moving car. The main aim of this unique simulation methodology was to replace the time-consuming and expensive real life vibration testing for a car-seated human body, with a non-robust and correctly postured virtual human model in a finite element environment. The output of this research work focused on the vertical accelerations, vertical displacement, and frequency, and the results obtained from this research work were validated through comparison to real life test data and information provided in other similar research works. The validation study showed that this unique simulation methodology can successfully be implemented to anticipate accelerations and frequencies at different points of a car-seated human body in order to optimize human health, comfort, and safety.

Acute Physiological Responses Following a Bout of Vigorous Exercise in Military Soldiers and First Responders with PTSD: An Exploratory Pilot Study

Post-traumatic stress disorder (PTSD) is a prevalent and debilitating condition associated with psychological conditions and chronic diseases that may be underpinned by dysfunction in the autonomic nervous system (ANS), the hypothalamic-pituitary-adrenal (HPA) axis and chronic systemic low-grade inflammation. The objective of this pilot study was to determine psychological, ANS [heart rate variability (HRV)], HPA (salivary cortisol) and inflammatory (salivary C-Reactive Protein) responses to a bout of vigorous exercise in male first responders, military veterans and active duty personnel with (n = 4) and without (n = 4) PTSD. Participants (50.1 ± 14.8 years) performed a thirteen-minute, vigorous intensity (70%–80% of heart rate max), one-on-one boxing session with a certified coach. Physiological and psychological parameters were measured before, during, immediately after to 30 min post-exercise, and then at 24 h and 48 h post. The effect sizes demonstrated large to very large reductions in HRV that lasted up to 48 h post-exercise in the PTSD group compared with unclear effects in the trauma-exposed control (TEC) group. There were unclear effects for depression, anxiety and stress as well as salivary biomarkers for both groups at all time-points. Findings may reflect stress-induced changes to the ANS for PTSD sufferers.

Dual-energy X-ray absorptiometry-assessed adipose tissues in metabolically unhealthy normal weight Asians

Normal body mass index (BMI) is associated with lower risk for cardiometabolic diseases. However, there is a subset of individuals with BMI in this range who present with this metabolic abnormality (called metabolically unhealthy normal weight, MUHNW). Here we aimed to assess the adipose characteristics of people with MUHNW using dual-energy X-ray absorptiometry (DXA). This study included 3259 people with normal BMI who underwent health examinations from January 1, 2007 through December 31, 2016. Body fat percentage (%BF), android-gynoid percent fat ratio (AG ratio), and visceral adipose tissue (VAT) were measured simultaneously using DXA CoreScan software. Those with MUHNW comprised 12.67% of the sample. Among those with MUHNW, 71.6% of the women and 56.5% of the men showed high VAT amounts, but less than 40% of either showed high %BFs. Furthermore, considering the combined effects of fat amount and distribution, a normal BMI accompanied by high AG ratio and/or high VAT mass but low %BF presents a much higher risk for metabolic syndrome than when %BF is high, most predominantly in women. In conclusion, using DXA-measured abdominal fat, particularly VAT accumulation, is clinically more important than using %BF when assessing metabolic syndrome in those with normal BMI.

Impact of smoking and physical inactivity on self-rated health in women in Colombia

The aim of this study was to assess the association between poor and fair self-rested health, smoking, and leisure-time physical inactivity in Colombian women. A cross-sectional study using the data from the 2010 Colombian National Demographics and Health (ENDS) and Nutritional Situation (ENSIN) Surveys was conducted. Multivariate logistic analysis for self-perceived health status in 12,431 women aged 13–49 years old and 8224 women aged 18–64 years old were performed. Independent variables included smoking, leisure-time physical inactivity, anthropometric and socio-demographic information. Current smoking and leisure-time physical inactivity were associated with poor and fair self-rated health status (OR 1.78, CI 1.41, 2.25; OR 1.30, CI 1.03, 1.62; respectively). Other significantly associated variables were age (OR 1.68, CI 1.46, 1.92 for 30–49 years; OR 2.32, CI 1.96, 2.74 for 50–64 years), socio-economic strata (OR 7.24, CI 3.81, 13.76 for strata 1–3), educational level (OR 1.70 to 2.77 compared to technical or university), obesity (OR 0.81, CI 0.70, 0.93 for normal body mass index), geographical region (OR 0.67, CI 0.53, 0.85 for Bogotá, compared to Amazon and Orinoco regions), and no affiliation to health system (OR 1.22, CI 1.03, 1.44). Smoking and leisure-time physical inactivity were significantly associated with poor and fair self-rated health in Colombian women. Promoting leisure-time physical activity and implementing smoking cessation strategies specifically in female population, mainly from low to medium strata are suggested to improve their self-perceived health status and control chronic noncommunicable diseases.

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The prevalence of current smoking in Colombian adult women in 2010 was 3% and leisure-time physical inactivity was 94%.

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Poor and fair self-perceived health status was significantly associated with the above and with increased age and obesity.

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Low education, low to medium socio-economic strata, region, and no affiliation to health system were also associated.

An anthropometry-based equation of fat mass percentage as a valid discriminator of obesity

OBJECTIVE

To develop a new predictive equation for fat mass percentage (%FM) based on anthropometric measurements and to assess its ability to discriminate between obese and non-obese individuals.

DESIGN

Cross-sectional study.

SETTING

Mexican adults.ParticipantsAdults (n 275; 181 women) aged 20-63 years with BMI between 17·4 and 42·4 kg/m2.

RESULTS

Thirty-seven per cent of our sample was obese using %FM measured by air-displacement plethysmography (BOD POD®; Life Measurement Instruments). The fat mass was computed from the difference between weight and fat-free mass (FFM). FFM was estimated using an equation obtained previously in the study from weight, height and sex of the individuals. The %FM estimated from the obtained FFM showed a sensitivity of 90·3 (95 % CI 86·8, 93·8) % and a specificity of 58·0 (95 % CI 52·1, 63·8) % in the diagnosis of obesity. Ninety-three per cent of participants with obesity and 65 % of participants without obesity were correctly classified.

CONCLUSIONS

The anthropometry-based equation obtained in the present study could be used as a screening tool in clinical and epidemiological studies not only to estimate the %FM, but also to discriminate the obese condition in populations with similar characteristics to the participant sample.

A descriptive study on selected growth parameters and growth hormone receptor gene in healthy young adults from the American Midwest

CONTEXT

The first study of growth hormone receptor (GHR) genotypes in healthy young adults in the United States attending a Midwestern university and impact on selected growth parameters.

OBJECTIVE

To describe the frequency of GHR genotypes in a sample of healthy young adults from the United States attending a university in the Midwest and analyze the relationship between GHR genotypes and selected growth parameters.

DESIGN

Saliva was collected from 459 healthy young adults (237 females, 222 males; age range = 18-25 y) and DNA isolated for genotyping of GHR alleles (fl/fl, fl/d3, or d3/d3). Selected growth parameters were collected and GHR genotype data examined for previously reported associations (e.g., height, weight or bone mass density) or novel findings (e.g., % body water and index finger length).

RESULTS

We found 219 participants (48%) homozygous for fl/fl, 203 (44%), heterozygous fl/d3 and 37 (8%) homozygous d3/d3. The distribution of GHR genotypes in our participants was consistent with previous reports of non-US populations. Several anthropometric measures differed by sex. The distribution of GHR genotypes did not significantly differ by sex, weight, or other anthropometric measures. However, the fl/d3 genotype was more common among African-Americans.

CONCLUSIONS

Our study of growth and anthropometric parameters in relationship to GHR genotypes found no association with height, weight, right index finger length, BMI, bone mass density, % body fat or % body water in healthy young adults. We did identify sex differences with increased body fat, decreased bone density, body water and index finger length in females.

Indicators of accumulated fat are stronger associated with prehypertension compared with indicators of circulating fat: A cross-sectional study

Recently, prehypertension has been considered as a risk factor for cardiovascular disease because it can progress to hypertension. The association between obesity and dyslipidemia with raised blood pressure has been reported in some studies; however, the ability of indicators of such conditions to predict prehypertension has been scarcely explored. In this cross-sectional study, we compared the ability of indicators of accumulated and circulating fat to discriminate between prehypertensive and normotensive Mexico City residents (n = 1377). The indicators were classified based on the parameters needed for their calculation: including only circulating fat (IOCFi) (e.g., Castelli risk indexes), including only accumulated fat (IOAFi) (e.g., waist circumference [WC]), and mixed (e.g., lipid accumulation product [LAP]). We compared the areas under the receiving operating characteristic curves (AURCs) and estimated the cutoff points for each indicator and their associated risk of prehypertension. The IOAFi had the greatest AURCs, followed by mixed and IOCFi; the AURCs for WC were the highest (AURC = 0.688 and 0.666 for women and men, respectively). The highest odds ratios for prehypertension were those associated with the cutoff points for IOAFi and LAP (e.g., OR = 2.8 for women with WC > 83.5 cm and OR = 2.6 for men with WC > 87.5 cm). Early detecting people at risk of cardiovascular disease is a necessity and given that WC had a better performance than the other indexes and it is relatively easy to measure, it has the potential of being used as a complementary measure in routine clinical examinations and by the general population as an auto-screening measurement to detect prehypertension.

Central obesity and body fat, but not body mass index, are associated with the Pro12Ala polymorphism in the peroxisome proliferator-activated receptor γ gene in a population with a high consumption of saturated and trans-fatty acids

The relationship of the Pro12Ala polymorphism in the peroxisome proliferator-activated receptor γ (PPARγ) gene with obesity and its modulation by dietary fat has been proposed, but the few studies addressing this issue have yielded controversial results. In a Mexican population characterized by high-fat consumption, we hypothesized that the Pro12Ala PPARγ genotype is related to obesity and this relationship is modulated by intake of saturated fatty acids (SFAs) and trans-fatty acids (TFAs). We recruited 69 adults for this cross-sectional study. The Pro12Ala PPARγ polymorphism was determined from blood genomic DNA by using real-time polymerase chain reaction. Univariate and multivariate logistic regression analyses were performed. Pro12Ala showed a positive association with central obesity (adjusted odds ratio, 7.38; 95% confidence interval, 1.19-45.77; P = .032) and percentage of body fat (%BF; adjusted odds ratio, 1.08; 95% confidence interval, 1.00-1.17; P = .048), suggesting that Pro12Ala carriers are more likely to have central obesity and a higher %BF than Pro12Pro carriers. A modifying effect was observed for the SFAs strata: we found a significant association between the Pro12Ala polymorphism and %BF in the high-SFA-intake stratum (P < .04), but not in the low-intake stratum (P > .7). No modifying effect was observed for the TFAs strata. In addition, the impact of total energy intake on obesity in Pro12Ala carriers seemed to be stronger than that in the wild-type genotype carriers. As hypothesized, our data demonstrated a relationship between the Pro12Ala PPARγ polymorphism and the presence of obesity, which is modulated by SFA intake but not TFA intake.

Predictive capacity of indicators of adiposity in the metabolic syndrome in elderly individuals

ABSTRACT Objective To evaluate the predictive ability of adiposity indicators as MetS predictors in elderly individuals. Methods Cross-sectional study enrolled in the Estratégia Saúde da Família (Family Health Strategy). Anthropometric measurements were measured. Body Mass Index, Waist-Hip Ratio, Waist-Height Ratio, Conicity Index and Body Adiposity Index were calculated. Blood was collected and resting blood pressure was measured. MetS was classified according to the harmonizing criteria. The predictive ability of anthropometric variables was evaluated using Receiver Operating Characteristic curves. Results Regarding male individuals, our research indicates that the BMI, Waist-Height Ratio and Waist Hip Ratio are better predictors and they are equivalent to each other. As for female individuals, results show that the Body Mass Index and Waist-Height Ratio are better predictors and equivalent to each other. Conclusion Waist-Height Ratio and Body Mass Index are good MetS predictors for elderly individuals, especially among men. More research in this area is important. Comitê de Ética em Pesquisa com Seres Humanos da Universidade Federal de Viçosa. (Viçosa University Ethics Committee in Research with Human Beings) (nº 039/2011).

Percentage of Body Fat and Fat Mass Index as a Screening Tool for Metabolic Syndrome Prediction in Colombian University Students

High body fat is related to metabolic syndrome (MetS) in all ethnic groups. Based on the International Diabetes Federation (IDF) definition of MetS, the aim of this study was to explore thresholds of body fat percentage (BF%) and fat mass index (FMI) for the prediction of MetS among Colombian University students. A cross-sectional study was conducted on 1687 volunteers (63.4% women, mean age = 20.6 years). Weight, waist circumference, serum lipids indices, blood pressure, and fasting plasma glucose were measured. Body composition was measured by bioelectrical impedance analysis (BIA) and FMI was calculated. MetS was defined as including more than or equal to three of the metabolic abnormalities according to the IDF definition. Receiver operating curve (ROC) analysis was used to determine optimal cut-off points for BF% and FMI in relation to the area under the curve (AUC), sensitivity, and specificity in both sexes. The overall prevalence of MetS was found to be 7.7%, higher in men than women (11.1% vs. 5.3%; p < 0.001). BF% and FMI were positively correlated to MetS components (p < 0.05). ROC analysis indicated that BF% and FMI can be used with moderate accuracy to identify MetS in university-aged students. BF% and FMI thresholds of 25.55% and 6.97 kg/m² in men, and 38.95% and 11.86 kg/m² in women, were found to be indicative of high MetS risk. Based on the IDF criteria, both indexes’ thresholds seem to be good tools to identify university students with unfavorable metabolic profiles.

Fatness mediates the influence of muscular fitness on metabolic syndrome in Colombian collegiate students

The purpose of this study was two-fold: to analyze the association between muscular fitness (MF) and clustering of metabolic syndrome (MetS) components, and to determine if fatness parameters mediate the association between MF and MetS clustering in Colombian collegiate students. This cross-sectional study included a total of 886 (51.9% women) healthy collegiate students (21.4 ± 3.3 years old). Standing broad jump and isometric handgrip dynamometry were used as indicators of lower and upper body MF, respectively. Also, a MF score was computed by summing the standardized values of both tests, and used to classify adults as fit or unfit. We also assessed fat mass, body mass index, waist-to-height ratio, and abdominal visceral fat, and categorized individuals as low and high fat using international cut-offs. A MetS cluster score was derived by calculating the sum of the sample-specific z-scores from the triglycerides, HDL cholesterol, fasting glucose, waist circumference, and arterial blood pressure. Linear regression models were used to examine whether the association between MF and MetS cluster was mediated by the fatness parameters. Data were collected from 2013 to 2016 and the analysis was done in 2016. Findings revealed that the best profiles (fit + low fat) were associated with lower levels of the MetS clustering (p <0.001 in the four fatness parameters), compared with unfit and fat (unfit + high fat) counterparts. Linear regression models indicated a partial mediating effect for fatness parameters in the association of MF with MetS clustering. Our findings indicate that efforts to improve MF in young adults may decrease MetS risk partially through an indirect effect on improvements to adiposity levels. Thus, weight reduction should be taken into account as a complementary goal to improvements in MF within exercise programs.

Waist-to-height ratio is the best anthropometric predictor of hypertension: A population-based study with women from a state of northeast of Brazil

The WHO recommends the use of some anthropometric parameters as a screening resource for individuals under cardiometabolic risk. However, in the validation of these indicators, Brazilian women were not included. These women have different anthropometric profile compared to women who integrated the samples of the validation studies. We aimed to verify the accuracy of anthropometric indicators as a resource for the screening of women with hypertension. A cross-sectional study, with a probability sample of 3143 women (20-49 years) from the state of Alagoas (northeast of Brazil), was carried out. Hypertension was identified by systolic blood pressure (SBP) ≥140 mm Hg and/or diastolic BP ≥90 mm Hg and/or regular use of antihypertensive drugs. The anthropometric indicators analyzed were BMI, waist circumference, waist-to-hip ratio, waist-to-height ratio (WHtR), body fat percentage, and conicity index. The accuracy definition of the indicators and the identification of best cut-off points were carried out on the basis of ROC curve analysis and Youden index, respectively. The prevalence of hypertension was 21.8%. All indicators used in hypertension identification had area under the ROC curve (AUC) >0.5. The WHtR with cut-off point of 0.54 was the best performance indicator (AUC = 0.72; P < 0.05; sensitivity = 67%, specificity = 66%). The WHtR with cut-off point of 0.54 has constituted the most accurate indicator in the screening of women with hypertension. In the absence of specific studies and considering the largest ethnic proximity and environmental/epidemiological similarity, the findings now obtained can be extended to women of other Brazilian states, especially those in the Northeastern region.

Cardiometabolic risk in young adults from northern Mexico: Revisiting body mass index and waist-circumference as predictors

BACKGROUND

A body mass index (BMI) ≥30 kg/m(2) and a waist circumference (WC) ≥80 cm in women (WCF) or ≥90 cm in men (WCM) are reference cardiometabolic risk markers (CMM) for Mexicans adults. However, their reliability to predict other CMM (index tests) in young Mexicans has not been studied in depth.

METHODS

A cross-sectional descriptive study evaluating several anthropometric, physiological and biochemical CMM from 295 young Mexicans was performed. Sensitivity (Se), specificity (Sp) and Youden's index (J) of reference BMI/WC cutoffs toward other CMM (n = 14) were obtained and their most reliable cutoffs were further calculated at Jmax.

RESULTS

Prevalence, incidence and magnitude of most CMM increased along the BMI range (p < 0.01). BMI explained 81 % of WC's variance [Se (97 %), Sp (71 %), J (68 %), Jmax (86 %), BMI = 30 kg/m(2)] and 4-50 % of other CMM. The five most prevalent (≥71 %) CMM in obese subjects were high WC, low HDL-C, and three insulin-related CMM [Fasting insulin, HOMA-IR, and QUICKI]. For a BMI = 30 kg/m(2), J ranged from 16 % (HDL-C/LDL-C) to 68 % (WC), being moderately reliable (Jmax = 61-67) to predict high uric acid (UA), metabolic syndrome (MetS) and the hypertriglyceridemic-waist phenotype (HTGW). Corrected WCM/WCF were moderate-highly reliable (Jmax = 66-90) to predict HTGW, MetS, fasting glucose and UA. Most CMM were moderate-highly predicted at 27 ± 3 kg/m(2) (CI 95 %, 25-28), 85 ± 5 cm (CI 95 %, 82-88) and 81 ± 6cm (CI 95 %, 75-87), for BMI, WCM and WCF, respectively.

CONCLUSION

BMI and WC are good predictors of several CMM in the studied population, although at different cutoffs than current reference values.