Joint association between body fat and its distribution with all-cause mortality: A data linkage cohort study based on NHANES (1988-2011)

Advantages and Limitations of the Body Mass Index (BMI) to Assess Adult Obesity

Obesity reflects excessive fat deposits. At-risk individuals are guided by healthcare professionals to eat fewer calories and exercise more, often using body mass index (BMI; weight/height2) thresholds for screening and to guide progress and prognosis. By conducting a mini-narrative review of original articles, websites, editorials, commentaries, and guidelines, we sought to place BMI in the context of its appropriate use in population health, clinical screening, and monitoring in clinical care. The review covers studies and publications through 2023, encompassing consensus reviews and relevant literature. Recent consensus reviews suggest that BMI is a valuable tool for population surveys and primary healthcare screening but has limitations in predicting the risk of chronic diseases and assessing excess fat. BMI can guide nutritional and exercise counseling, even if it is inadequate for reliable individual risk prediction. BMI cut-offs must be reconsidered in populations of varying body build, age, and/or ethnicity. Since BMI-diagnosed overweight persons are sometimes physically and physiologically fit by other indicators, persons who are overweight on BMI should be more fully evaluated, diagnosed, and monitored with combined anthropometric and performance metrics to better clarify risks. The use of combined anthropometric and performance metrics involves integrating measurements of body composition with assessments of physical function and fitness to provide a more comprehensive evaluation of an individual's health and fitness status. Eligibility for bariatric surgery or semaglutide satiety/appetite-reduction medications should not be determined by BMI alone. Awareness of the advantages and limitations of using BMI as a tool to assess adult obesity can maximize its appropriate use in the context of population health and in rapid clinical screening and evaluation.

The longitudinal association of adipose-to-lean ratio with incident cardiometabolic morbidity: The CARDIA study

AIM

To assess the association of adipose-to-lean ratio (ALR) with incident type 2 diabetes mellitus (T2DM), hypertension, and dyslipidemia in middle adulthood.

METHOD

Black and White Coronary Artery Risk Development in Young Adults participants without T2DM, hypertension, or dyslipidemia in 2005-06 (baseline) were included. Baseline adipose and lean mass were assessed via dual-energy X-ray absorptiometry. ALR was calculated as adipose divided by lean mass and then standardized within sex strata. Single time-point incident morbidity was assessed every five years from baseline through 2016. Cox proportional hazards regression was used to estimate hazard ratios (HR) for morbidity over 10 years per 1-SD increment in ALR adjusted for cardiovascular risk factors.

RESULT

The cumulative incidence of T2DM was 7.9 % (129 events/N = 1643; 16,301 person-years), 26.7 % (485 events/N = 1819; 17,895 person-years) for hypertension, and 49.1 % (435 events/N = 855, 8089 person-years) for dyslipidemia. In the adjusted models, ALR was positively associated with a risk of T2DM (HR [95 % CI]; 1.69 [1.31, 2.19]) and hypertension (1.23 [1.08, 1.40]). There was no significant interaction between ALR and sex for any morbidity.

CONCLUSION

ALR in middle adulthood is associated with incident T2DM and hypertension. The extent to which localized body composition measures might inform morbidity risk merits further investigation.

Association between neck circumference and pulmonary function in Korean adults

Neck circumference (NC) is associated with various diseases. However, its association with pulmonary diseases remains unclear. This study aimed to investigate the association between NC and pulmonary function in Korean adults. Data from the 2019 Korean National Health and Nutrition Examination Survey were used, including forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). A total of 3818 adults aged 40 to 79 years were included in the analysis. Multivariable logistic regression models were used to examine factors associated with low pulmonary function (<80% of the predicted value) and calculate odds ratios (ORs) and 95% confidence intervals (CIs) for decreased lung function per 1-cm increase in NC. A negative correlation was observed between the NC and pulmonary function in both sexes. In multivariate logistic regression analyses, in contrast to men, women exhibited a notable relationship between increased NC and impaired pulmonary function, with a more pronounced effect observed in FVC (OR, 1.14; 95% CI, 1.05-1.24). Central obesity may play a role in pulmonary function decline. Understanding this relationship can inform preventive strategies and interventions to improve the respiratory health of individuals with central obesity.

Update on Adipose Tissue and Cancer

Adipose tissue is the largest endocrine organ and an accepted contributor to overall energy homeostasis. There is strong evidence linking increased adiposity to the development of 13 types of cancer. With increased adiposity comes metabolic dysfunction and insulin resistance, and increased systemic insulin and glucose support the growth of many cancers, including those of the colon and endometrium. There is also an important direct crosstalk between adipose tissue and various organs. For instance, the healthy development and function of the mammary gland, as well as the development, growth, and progression of breast cancer, are heavily impacted by the breast adipose tissue in which breast epithelial cells are embedded. Cells of the adipose tissue are responsive to external stimuli, including overfeeding, leading to remodeling and important changes in the secretion of factors known to drive the development and growth of cancers. Loss of factors like adiponectin and increased production of leptin, endotrophin, steroid hormones, and inflammatory mediators have been determined to be important mediators of the obesity-cancer link. Obesity is also associated with a structural remodeling of the adipose tissue, including increased localized fibrosis and disrupted angiogenesis that contribute to the development and progression of cancers. Furthermore, tumor cells feed off the adipose tissue, where increased lipolysis within adipocytes leads to the release of fatty acids and stromal cell aerobic glycolysis leading to the increased production of lactate. Both have been hypothesized to support the higher energetic demands of cancer cells. Here, we aim to provide an update on the state of the literature revolving around the role of the adipose tissue in cancer initiation and progression.

Associations of artificially sweetened beverages, sugar-sweetened beverages, and pure fruit/vegetable juice with visceral adipose tissue mass

OBJECTIVE

To test the associations of sugar-sweetened beverage, artificially sweetened beverage, and pure fruit/vegetable juice consumption with visceral adipose tissue (VAT) mass at baseline and follow-up and to determine whether BMI and genetic risk of VAT mass modified the associations.

METHODS

A total of 203,348 participants from UK Biobank with consumption data on three beverages were included. Participants were categorized into nonconsumers and consumers with >0-1, >1-2 and >2 L/week. A sex-specific prediction model was used to calculate VAT mass. A weighted genetic risk score for high VAT mass was calculated.

RESULTS

The participants with a sugar-sweetened beverage and artificially sweetened beverage consumption of >2 L/week had the greatest B values [B (95% CI): 24.02 (16.53, 31.51) and 60.81 (52.08, 69.54) in men, respectively; 10.20 (5.92, 14.48) and 24.72 (20.80, 28.64) in women]. Low and moderate intake of pure fruit/vegetable juices showed a significantly inverse association with VAT mass in men [-10.52 (-15.37, -5.67); -6.46 (-11.27, -1.65)] and women [-6.70 (-8.99, -4.41); -5.93 (-8.33, -3.54)]. Regarding changes in VAT mass, participants who consumed >2 L/week of sugar-sweetened beverages and artificially sweetened beverages had greater changes. BMI but not genetic risk modified the associations between beverage intake and VAT mass, which were strengthened in participants with BMI ≥25 kg/m2 for sugar-sweetened and artificially sweetened beverage consumption.

CONCLUSIONS

Higher consumption of sugar-sweetened beverages or artificially sweetened beverages was associated with greater VAT mass regardless of genetic risk. Mild-to-moderate intake of pure fruit/vegetable juices was linked to lower VAT mass.

Temporal trends in obesity defined by the relative fat mass (RFM) index among adults in the United States from 1999 to 2020: a population-based study

OBJECTIVES

The body mass index (BMI) largely underestimates excess body fat, suggesting that the prevalence of obesity could be underestimated. Biologically, women are known to have higher body fat than men. This study aimed to compare the temporal trends in general obesity by sex, ethnicity and age among adults in the USA using the relative fat mass (RFM), a validated surrogate for whole-body fat percentage and BMI.

DESIGN

Population-based study.

SETTING

US National Health and Nutrition Examination Survey, from 1999-2000 to 2017-March 2020.

PARTICIPANTS

A representative sample of adults 20-79 years in the USA.

MAIN OUTCOME MEASURES

Age-adjusted prevalence of general obesity. RFM-defined obesity was diagnosed using validated cut-offs to predict all-cause mortality: RFM≥40% for women and ≥30% for men. BMI-defined obesity was diagnosed using a cut-off of 30 kg/m2.

RESULTS

Analysis included data from 47 667 adults. Among women, RFM-defined obesity prevalence was 64.7% (95% CI 62.1% to 67.3%) in 2017-2020, a linear increase of 13.9 percentage points (95% CI 9.0% to 18.9%; p<0.001) relative to 1999-2000. In contrast, the prevalence of BMI-defined obesity was 42.2% (95% CI 39.4% to 45.0%) in 2017-2020. Among men, the corresponding RFM-defined obesity prevalence was 45.8% (95% CI 42.0% to 49.7%), a linear increase of 12.0 percentage points (95% CI 6.6% to 17.3%; p<0.001). In contrast, the prevalence of BMI-defined obesity was 42.0 (95% CI 37.8% to 46.3%). The highest prevalence of RFM-defined obesity across years was observed in older adults (60-79 years) and Mexican Americans, in women and men. Conversely, the highest prevalence of BMI-defined obesity across years was observed in middle-age (40-59 years) and older adults, and in African American women.

CONCLUSIONS

The use of a surrogate for whole-body fat percentage revealed a much higher prevalence of general obesity in the USA from 1999 to 2020, particularly among women, than that estimated using BMI, and detected a disproportionate higher prevalence of general obesity in older adults and Mexican Americans.

Trends in global health research among universities in China: a bibliometric analysis

BACKGROUND

There has been considerable progress in developing global health education and research in China. Nevertheless, evidence of the progress of Chinese universities' contributions to global health research is limited. More efforts are needed to depict the progress Chinese universities have collectively made in advancing the field of global health. This study aimed to examine Chinese universities' collective contributions to global health research by describing the longitudinal trends in global health research publications, uncovering research themes in global health, and exploring collaboration patterns.

METHODS

A comprehensive bibliometric analysis was conducted for original research studies of the ten founding members of the China Consortium of Universities for Global Health, one of the largest networks of global health research and education in China.

RESULTS

We found that (1) the number of research publications in the field of global health has steadily increased from 2014 to 2020, (2) non-communicable disease was the most popular research topic, accounting for over one-third of total publications, followed by maternal and child health and neurological and mental disorders and diseases, (3) less than one-fifth of papers involved primary data collection, with the majority of the study populations from low-income and lower-middle-income countries in Asia and Africa, and (4) a sizable collaboration network has been established with co-authors from over 200 oversea universities or organizations, with about one third from the US.

CONCLUSIONS

Despite a variety of challenges and barriers, Chinese universities have been playing an increasingly important role in global health research as assessed by peer-reviewed publications over the last decade. More concerted efforts by multiple stakeholders, including government, private sectors, funding agencies, academic institutions, and researchers, are needed to advance the development of global health research in China.

U-shaped relationship between subcutaneous adipose tissue index and mortality in liver cirrhosis

BACKGROUND

Subcutaneous and visceral adipose tissues are important body components, but their effects on the mortality in patients with liver cirrhosis remain controversial based on the current evidence.

METHODS

We retrospectively identified 372 eligible patients in whom subcutaneous adipose tissue index (SATI) and visceral adipose tissue index (VATI) could be measured by computed tomography images at the third lumbar vertebra. The association of SATI and VATI with the risk of death was evaluated on a continuous scale with restricted cubic spline curves based on Cox proportional hazards models. Cumulative probability of mortality was estimated by Nelson-Aalen cumulative risk curve analyses. Independent predictors of death were evaluated by competing risk analyses after adjusting for age, sex, and model for end-stage liver disease score.

RESULTS

Majority of patients were male (69.4%) with a mean age of 55.40 ± 10.68 years. SATI had a U-shaped association with mortality (P for non-linearity <0.001). Cutoff values of SATI were 19.7 and 51.8 cm² /m² at the points where hazard ratios were just <1.2. SATI was categorized as low (<19.7 cm² /m² ), moderate (19.7-51.8 cm² /m² ), and high (>51.8 cm² /m² ) level. There was no significant difference in the cumulative probability of mortality between low versus moderate SATI groups (Gray's test, P = 0.052) and high versus moderate SATI groups (Gray's test, P = 0.054). Competing risk analyses demonstrated that low SATI could increase the mortality compared with moderate SATI (subdistribution hazard ratio [sHR] = 1.66, 95% confidence interval [CI]: 0.992-2.78, P = 0.054) and was an independent predictor of death (sHR = 1.86, 95% CI: 1.059-3.28, P = 0.031). Competing risk analyses also demonstrated that high SATI could significantly increase the mortality compared with moderate SATI (sHR = 1.6, 95% CI: 1-2.54, P = 0.049), and was an independent predictor of death (sHR = 2.007, 95% CI: 1.195-3.37, P = 0.0085). VATI had an irregularly shaped association with mortality (P for non-linearity <0.001). Cutoff values of VATI were 9.8 and 40.2 cm² /m² at the points where hazard ratios were just <1.2. VATI was categorized as low (<9.8 cm² /m² ), moderate (9.8-40.2 cm² /m² ), and high (>40.2 cm² /m² ) level. There was no significant difference in the cumulative probability of mortality between low versus moderate VATI groups (Gray's test, P = 0.381) and high versus moderate VATI groups (Gray's test, P = 0.787). Competing risk analyses demonstrated that neither low (sHR = 1.27, 95% CI: 0.599-2.7, P = 0.53) nor high VATI (sHR = 0.848, 95% CI: 0.539-1.34, P = 0.48) was an independent predictor of death compared with moderate VATI.

CONCLUSIONS

Both excessive deficiency and accumulation of subcutaneous adipose tissues negatively influence the outcomes of cirrhotic patients.

Age-specific and sex-specific associations of visceral adipose tissue mass and fat-to-muscle mass ratio with risk of mortality

BACKGROUND

Limited studies have explored the association between visceral adipose tissue (VAT) mass and fat-to-muscle mass ratio (FMR) and mortality. We aimed to evaluate the sex-specific association of VAT and FMR with all-cause and cause-specific mortality by age.

METHODS

A total of 438 896 participants (49.8% men, mean age ± standard deviation: 57 ± 8 years for men; 56 ± 8 years for women) were included from the UK Biobank cohort. The nature of VAT was predictive, as obtained by sex-stratified, non-linear prediction models. Fat and muscle mass were estimated using a bioelectrical impedance assessment device. FMR was calculated as the fat mass divided by the muscle mass in the whole body. VAT and FMRs were divided into quintiles in ascending order, and the 3rd quintile was used as the reference. Cox regression analyses were used to estimate the associations between VAT, FMR and mortality.

RESULTS

During a median of 12.4 years of follow-up, we documented 29 903 deaths. After adjusting for various covariates, the individuals in the highest quintiles of VAT and FMR had the highest hazard ratios (HRs) of all-cause mortality [1.24 (95% confidence interval: 1.17-1.33) for VAT and 1.24 (1.17-1.31) for FMR in men; and 1.11 (1.03-1.21) for VAT in women], except that the 1st quintile of FMR in women had the greatest HR [1.18 (1.09-1.27)]. Significant interactions were observed in both sexes according to age category (P for interaction < 0.05). Among men <50 years, participants in the 1st and 5th quintiles of VAT and FMR had significantly higher risks of mortality [1.30 (1.02-1.66) and 1.67 (1.27-2.19) in VAT; 1.25 (0.99-1.56) and 1.41 (1.11-1.79) in FMR, respectively]; in women, this phenomenon was observed in the ≥60 age group [1.16 (1.06-1.27) and 1.19 (1.08-1.31) in VAT; 1.18 (1.08-1.29) and 1.11 (1.01-1.22) in FMR, respectively]. VAT showed a linear positive association with mortality in women <60 years and a J-shaped association from respiratory disease in both sexes ≥60 years. FMR showed a linear positive association with mortality from cancer in men <60 years and a J-shaped association with mortality from cause-specific mortality in both sexes ≥60 years, except for mortality from cardiovascular disease in men.

CONCLUSIONS

Most associations of VAT and FMR with all-cause mortality were J-shaped and were significantly modified by age status (<50, 50-59 and ≥60 years). The clinical implication is that regarding body composition and VAT mass, different health strategies may be adopted for people of different sexes and ages.

Influence of changes in body fat on clinical outcomes in a general population: a 12-year follow-up report on the Ansan-Ansung cohort in the Korean Genome Environment Study

BACKGROUND

The impact of the changes in the obesity status on mortality has not been established; thus, we investigated the long-term influence of body fat (BF) changes on all-cause deaths and cardiovascular outcomes in a general population.

METHODS

A total of 8374 participants were observed for 12 years. BF was measured at least two times using a bioimpedance method. The causes of death were acquired from the nationwide database. A major adverse cardiovascular event (MACE) was defined as a composite of myocardial infarction, coronary artery disease, stroke, and cardiovascular death. Standard deviations (SDs) were derived using a local regression model corresponding to the time elapsed between the initial and final BF measurements (SD_T) and were used to standardize the changes in BF (ΔBF/SD_T).

RESULTS

The incidence rates of all-cause death, cardiovascular death, and MACE were the highest in the participants with ΔBF/SD_T <-1 and lowest in the participants with ΔBF/SD_T ≥1. Multivariate Cox proportional hazard models adjusted for relevant covariates, including baseline obesity and physical activity, showed that the risks of all-cause deaths (hazard ratio [HR] 0.58; 95% confidence intervals [CI] 0.53-0.64), cardiovascular deaths (HR 0.63; 95% CI 0.51-0.78) and MACEs (HR 0.68; 95% CI 0.62-0.75) decreased as ΔBF/SD_T increased. Subgroup analyses showed that existing cardiovascular diseases weakened the associations between higher ΔBF/SD_T and better outcomes, while high physical activity and exercise did not impact the associations.

CONCLUSION

Increasing BF was associated with a lower risk of all-cause death, cardiovascular death, and MACE in the general population.Key messagesIncreasing body fat is associated with a lower risk of all-cause death, cardiovascular death, and major cardiovascular adverse events in a low-risk ageing general population, independently of physical activity, underlying cardiovascular disease burden, changes in muscle mass, and baseline obesity status.Fatness measured at baseline requires adjustment for the changes in fatness during the follow-up to reveal its impact on the clinical outcomes.

Defining a minimal clinically meaningful difference in 12-month estimated glomerular filtration rate for clinical trials in deceased donor kidney transplantation

BACKGROUND

A Minimal Clinically Meaningful Difference (MCMD) has not been defined for Estimated glomerular filtration rate (eGFR). Our goal was to define the MCMD for eGFR anchored to kidney graft failure.

METHODS

A systematic review of studies with 12-month eGFR and subsequent renal graft failure was conducted. For observational studies, we calculated hazard ratio (HR) differences between adjacent eGFR intervals weighted by population distribution. Interventional trials yielded therapeutically induced changes in eGFR and failure risk. OPTN data analysis divided 12-month eGFR into bands for Cox regressions comparing adjacent eGFR bands with a death-censored graft survival outcome.

RESULTS

Observational studies indicated that lower eGFR was associated with increased death-censored graft failure risk; each 5 ml/min/1.73 m2 12-month eGFR band associated with a weighted incremental HR = 1.12 to 1.23. Clinical trial data found a 5 ml/min/1.73 m2 difference was associated with incremental HR = 1.16 to 1.35. OPTN analyses showed weighted mean HRs across 10, 7, and 5 ml/min/1.73 m2 bands of 1.47, 1.30, and 1.19.

CONCLUSIONS

A 5 ml/min/1.73 m2 difference in 12-month eGFR was consistently associated with ~20% increase in death-censored graft failure risk. The magnitude of effect has been interpreted as clinically meaningful in other disease states and should be considered the MCMD in renal transplantation clinical trials.

Associations of Skeletal Muscle Mass and Fat Mass With Incident Cardiovascular Disease and All-Cause Mortality: A Prospective Cohort Study of UK Biobank Participants

Background There is debate whether body mass index is a good predictor of health outcomes because different tissues, namely skeletal muscle mass (SMM) and fat mass (FM), may be differentially associated with risk. We investigated the association of appendicular SMM (aSMM) and FM with fatal and nonfatal cardiovascular disease (CVD) and all-cause mortality. We compared their prognostic value to that of body mass index. Methods and Results We studied 356 590 UK Biobank participants aged 40 to 69 years with bioimpedance analysis data for whole-body FM and predicted limb muscle mass (to calculate aSMM). Associations between aSMM and FM with CVD and all-cause mortality were examined using multivariable Cox proportional hazards models. Over 3 749 501 person-years of follow-up, there were 27 784 CVD events and 15 844 all-cause deaths. In men, aSMM was positively associated with CVD incidence (hazard ratio [HR] per 1 SD 1.07; 95% CI, 1.06-1.09) and there was a curvilinear association in women. There were stronger positive associations between FM and CVD with HRs per SD of 1.20 (95% CI, 1.19-1.22) and 1.25 (95% CI, 1.23-1.27) in men and women respectively. Within FM tertiles, the associations between aSMM and CVD risk largely persisted. There were J-shaped associations between aSMM and FM with all-cause mortality in both sexes. Body mass index was modestly better at discriminating CVD risk. Conclusions FM showed a strong positive association with CVD risk. The relationship of aSMM with CVD risk differed between sexes, and potential mechanisms need further investigation. Body fat and SMM bioimpedance measurements were not superior to body mass index in predicting population-level CVD incidence or all-cause mortality.

The Appraisal of Body Content (ABC) trial: Increased male or female adiposity does not significantly impact in vitro fertilization laboratory or clinical outcomes

OBJECTIVE

To investigate the impact of obesity as determined by bioelectric impedance analysis (BIA) and body mass index (BMI) on in vitro fertilization (IVF) laboratory and clinical outcomes.

DESIGN

Prospective cohort study.

SETTING

Academic-affiliated private practice.

PATIENT(S)

A total of 1,889 infertile couples undergoing IVF from June 2016 to January 2019.

INTERVENTION(S)

Female patients and male partners underwent BIA and BMI measurement at the time of oocyte retrieval. Embryology and clinical outcomes were prospectively tracked with comparison groups determined by percentage of body fat (%BF) and BMI categories.

MAIN OUTCOME MEASURE(S)

Fertilization rate, blastocyst formation rate, euploidy rate, miscarriage rate, sustained implantation rate, live birth rate, rates of low birth weight/very low birth weight, prematurity rates.

RESULT(S)

Fertilization rates and euploidy rates were equivalent among all women. Blastocyst formation rates were slightly higher (55%) in women with an obese %BF compared with all other %BF categories (51%); however, this trend was not noted in women defined as obese by BMI. Miscarriage rates, sustained implantation rates, and live birth rates were equivalent among all women. The rate of very low birth weight was low but increased in obese women (3%) versus underweight, normal-weight, and overweight counterparts (0%-1.3%) as determined by %BF and BMI. Obesity in men did not significantly affect any embryologic or clinical outcomes.

CONCLUSION(S)

Although maternal obesity imposes a small but increased risk of very low birth weight infants, most embryology and pregnancy outcomes are equivalent to normal weight patients. Paternal obesity does not appear to affect IVF, pregnancy, or delivery outcomes.

Obesity and overall mortality: findings from the Jackson Heart Study

Background

Overall mortality has been reported to be lower among individuals classified as overweight/obese when compared with their normal weight counterparts (“obesity paradox”) when obesity classification is based on the body mass index (BMI). One possible reason for this apparent paradox is that BMI is not a reliable measure of obesity-related risk as it does not differentiate fat mass from lean muscle mass or fat mass phenotypes. Waist circumference (WC), as a measure of central adiposity, may be a better indicator of obesity-related risk. We examined the association of overall mortality with BMI and with WC measures, including WC, waist-to-height ratio (WHtR) and waist-to-hip ratio (WHR).

Methods

Data from 3976 African American participants (551 deaths) in the Jackson Heart Study (JHS) were analyzed. Cox regression models were used to perform survival analysis. Obesity measures were analyzed as dichotomous (obese/non-obese) and continuous variables. Baseline covariates included age, sex and smoking status.

Results

Comparing obese to non-obese participants, adjusted hazard ratios (95% CI) for overall mortality were 1.14 (0.96, 1.35), 1.30 (1.07, 1.59), 1.02 (0.73, 1.41) and 1.45 (1.18, 1.79) when using BMI, WC, WHtR and WHR, respectively. For BMI, WC and WHtR, a J-shaped relationship was observed with overall mortality. For WHR, a monotonic increasing relationship was observed with overall mortality.

Conclusions

In the JHS, we found that obesity as defined by WC and WHR was associated with an increased risk of overall and CVD mortality, while obesity defined by BMI was associated only with an increased risk of CVD mortality. WHR was the only obesity measure that showed a monotonic increasing relationship with overall and CVD mortality.

Which anthropometric measures best identify excess weight in older adults?

OBJECTIVES: To estimate the prevalence of and factors associated with excess weight in older adults according to body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WtHR), as well as to measure the differences between the prevalences estimated by WC and WtHR in relation to BMI. METHODS: This cross-sectional study was conducted in 2016 – 2017 with 549 older adults (72–102 years) from Campinas and Ermelino Matarazzo, two cities in the state of São Paulo, Brazil. Excess weight was defined according to cut-off points established for older adults. Multiple Poisson regression analysis was performed. RESULTS: The overweight/obesity prevalences were 47.36% (BMI), 61.38% (WC) and 65.57% (WtHR), being higher in women and in those with hypertension, diabetes, polypharmacy, and normal calf circumference. They were also higher in the youngest age strata (BMI and WC), in those with arthritis/rheumatism (BMI), and in those with slow gait (WtHR). The estimated overweight/obesity prevalences according to WC and WtHR were 29.00% and 38.00% higher, respectively, than BMI. In the multiple model, there was a higher prevalence of adiposity among diabetics and those with normal calf circumference. CONCLUSIONS: Measures of abdominal adiposity provided a better diagnosis of excess weight. We recommended that health professionals consider using WtHR in anthropometric assessment of older adults, especially regarding adiposity.

The appraisal of body content (ABC) trial: obesity does not significantly impact gamete production in infertile men and women

PURPOSE

As obesity becomes increasingly prevalent, its impact on fertility has been a subject of great debate. Nearly all prior research is retrospective and evaluates obesity utilizing body mass index (BMI), which may overestimate adiposity in individuals with a greater amount of lean muscle and underestimate adiposity in those with less muscle mass.

METHODS

We prospectively evaluated 2013 couples undergoing infertility treatment with in vitro fertilization (IVF). Percent body fat (%BF) was measured by use of a bioelectric impedance analysis (BIA) scale at baseline. BMI was also determined. Ovarian reserve parameters, ovarian response to controlled ovarian hyperstimulation, and semen analyses were measured in correlation with their %BF and BMI.

RESULTS

Females classified as obese based on %BF or BMI had lower serum FSH. However, when the analysis was limited to women without PCOS (n = 1706), obesity based on %BF or BMI was associated with lower serum AMH. Female obesity-regardless of a PCOS diagnosis-did not affect number of mature oocytes retrieved. Males who were in obese %BF category were found to have lower TMSC compared with normal weight counterparts (p < 0.05); however, the observed decrease was not significant enough to limit the success of assisted reproductive technologies.

CONCLUSIONS

These findings suggest that while obesity may affect ovarian reserve in women variably depending on presence of PCOS, it does not affect number of mature oocytes available after COH. Similarly, while a high %BF in males is associated with lower TMSC, the observed difference is unlikely to affect IVF outcomes.

Body composition parameters can better predict body size dissatisfaction than body mass index in children and adolescents

PURPOSE

Recent studies suggest that body mass index is not a reliable enough measurement for body composition in individuals, particularly in older and younger people. However, most research on body image has used the body mass index (BMI) as a physiological predictor of body satisfaction, particularly in children. The aim of this study was to investigate whether body composition is a better predictor of body size dissatisfaction in children than BMI.

METHODS

This is a cross-sectional study. Healthy children and adolescents aged 5-19 years, sex male and female, were recruited using a convenience sample in Brazil. BMI was measured according to the international standardization method and body composition was measured by bioelectrical impedance analysis (BIA) with a portable device model (BIA InBodyS10 multi-frequency, USA). Body size dissatisfaction was assessed using the Kakeshita's Figure Rating Scale for Brazilian Children. Data were analyzed with logistic regression analysis.

RESULTS

A total of 547 participants were evaluated, including 54% females and 67% Caucasian, with a mean age of 11.4 ± 3.8 years. The mean BMI was 20.5 ± 4.6 kg/m², and the mean percentages of fat and lean mass were 23.01 ± 10.59% and 72.84 ± 10.03%, respectively. In the multivariable model, only body composition was significantly associated with body size dissatisfaction (odds ratio: 1.849 (1.085-3.149, p = 0.024) and 1.828 (1.043-3.202, p = 0.035), respectively).

CONCLUSIONS

Body composition measures can better predict body size dissatisfaction in children and adolescents than BMI. This result may be relevant for the design of future studies on physiological indicators and body satisfaction.

LEVEL OF EVIDENCE

Level V, cross-sectional study.

Cardiovascular Adaptations to Four Months Training in Middle-Aged Amateur Long-Distance Skiers

Cross-country skiing has a positive effect on health. However, without an individual, thoughtful, and professional plan, it can cause irreversible health problems from overload and injury. The impact of exercise on results is well understood within the group of professional athletes. However, this remains unknown within the group of amateur cross-country skiers and marathon runners—in particular, the impact of the summer preparation period in which training loads performed in the oxygen zone combined with resistance training dominate. The aim of this study was to assess changes in the cardiovascular capacity and body mass composition of male cross-country skiers in the preparation period of their macrocycle. Variables were analyzed using basic descriptive statistics: mean and standard deviation (SD). To compare the results from both measurements (initial and final) the paired Wilcoxon test was used. A statistically significant increase was noted in maximum oxygen uptake and maximum minute ventilation, and a decrease in body fat content, maximum lactate concentration and lactate threshold, and heart rate on anaerobic threshold. Research indicated that in the amateur group increases similar to those in top competitors were achieved in the parameters tested, but the initial level was often significantly lower.

High-Intensity Interval Training in Cardiac Rehabilitation: Impact on Fat Mass in Patients With Myocardial Infarction

OBJECTIVE

To examine the effect of high-intensity interval training (HIIT) on body fat mass and distribution in patients with myocardial infarction (MI) who underwent cardiac rehabilitation (CR).

PATIENTS AND METHODS

We retrospectively screened 391 consecutive patients with MI enrolled in CR between September 1, 2015, and February 28, 2018. We included 120 patients who completed 36 CR sessions and underwent pretest-posttest dual-energy x-ray absorptiometry; 90 engaged in HIIT, and 30 engaged in moderate-intensity continuous training (MICT). High-intensity interval training included 4 to 8 alternating intervals of high- (30-60 seconds at a rating of perceived exertion [RPE] of 15-17 [Borg scale range, 6-20]) and low-intensity (1-5 minutes at RPE <14), and MICT performed for 20 to 45 minutes of exercise at an RPE of 12 to 14. Body weight, fat mass, and lean mass were measured via dual-energy x-ray absorptiometry with lipid profile measured via clinical procedures.

RESULTS

The HIIT and MICT groups were similar in age (67 vs 67 years), sex (26.7% [24 of 90 patients in the HIIT group] vs 26.7% [8 of 30 in the MICT group), and body mass index (30.3 vs 29.5 kg/m²) at baseline. The HIIT group had greater reductions in body fat percentage (P<.001), fat mass (P<.001), abdominal fat percentage (P<.001), waist circumference (P=.01), total cholesterol (P=.002), low-density lipoprotein cholesterol (P<.001), and triglycerides (P=.006). Improvements in total body mass and body mass index were not different across groups. After matching exercise duration, exercise intensity, and energy expenditure, HIIT-induced improvements in total fat mass (P=.02), body fat percentage (P=.01), and abdominal fat percentage (P=.02) persisted.

CONCLUSION

Our data suggest that supervised HIIT results in significant reductions in total fat mass (P<.001) and abdominal fat percentage (P<.001) and improved lipid profile in patients with MI who undergo CR.

High-intensity interval training improves metabolic syndrome and body composition in outpatient cardiac rehabilitation patients with myocardial infarction

BACKGROUND

To examine the effect of high-intensity interval training (HIIT) on metabolic syndrome (MetS) and body composition in cardiac rehabilitation (CR) patients with myocardial infarction (MI).

METHODS

We retrospectively screened 174 consecutive patients with MetS enrolled in CR following MI between 2015 and 2018. We included 56 patients who completed 36 CR sessions and pre-post dual-energy X-ray absorptiometry. Of these patients, 42 engaged in HIIT and 14 in moderate-intensity continuous training (MICT). HIIT included 4-8 intervals of high-intensity (30-60 s at RPE 15-17 [Borg 6-20]) and low-intensity (1-5 min at RPE < 14), and MICT included 20-45 min of exercise at RPE 12-14. MetS and body composition variables were compared between MICT and HIIT groups.

RESULTS

Compared to MICT, HIIT demonstrated greater reductions in MetS (relative risk = 0.5, 95% CI 0.33-0.75, P < .001), MetS z-score (- 3.6 ± 2.9 vs. - 0.8 ± 3.8, P < .001) and improved MetS components: waist circumference (- 3 ± 5 vs. 1 ± 5 cm, P = .01), fasting blood glucose (- 25.8 ± 34.8 vs. - 3.9 ± 25.8 mg/dl, P < .001), triglycerides (- 67.8 ± 86.7 vs. - 10.4 ± 105.3 mg/dl, P < .001), and diastolic blood pressure (- 7 ± 11 vs. 0 ± 13 mmHg, P = .001). HIIT group demonstrated greater reductions in body fat mass (- 2.1 ± 2.1 vs. 0 ± 2.2 kg, P = .002), with increased body lean mass (0.9 ± 1.9 vs. - 0.9 ± 3.2 kg, P = .01) than the MICT. After matching for exercise energy expenditure, HIIT-induced improvements persisted for MetS z-score (P < .001), MetS components (P < .05), body fat mass (P = .002), body fat (P = .01), and lean mass (P = .03).

CONCLUSIONS

Our data suggest that, compared to MICT, supervised HIIT results in greater improvements in MetS and body composition in MI patients with MetS undergoing CR.

High abdominal adiposity and low phase angle in overweight renal transplant recipients

Obesity is associated with increased risk of cardiovascular disease (CVD). Body mass index (BMI) is the most used parameter for obesity screening. However, the evaluation of CVD risk in overweight individuals should include the assessment of body fat distribution and body composition. Renal transplant recipients (RTR) have a high CVD risk and frequently present weight gain and loss of lean mass. The aim of this study was to evaluate body fat distribution and body composition in overweight RTR. This cross-sectional study was conducted with 86 RTR and 86 hypertensive individuals (comparison group, CG) presenting BMI 25-35 Kg/m² and 45-70 years. Anthropometric evaluation included BMI, waist circumference, waist-to-height ratio, and a body shape index. Body composition was evaluated with bioelectrical impedance analysis (BIA). Glomerular filtration rate was estimated (eGFR) by CKD-EPI equation. RTR group (RTRG) and CG presented similar age and BMI. RTRG when compared to CG presented lower percentage of women and eGFR; higher central adiposity; and lower values of reactance, intracellular water, body cell mass and phase angle, more consistently observed in women. This study suggests that overweight RTR present higher abdominal adiposity and impairment in BIA parameters that are sensitive indicators of impaired membrane integrity, water distribution, and body cell mass.

Determinants of body fat distribution in humans may provide insight about obesity-related health risks

Obesity increases the risks of developing cardiovascular and metabolic diseases and degrades quality of life, ultimately increasing the risk of death. However, not all forms of obesity are equally dangerous: some individuals, despite higher percentages of body fat, are at less risk for certain chronic obesity-related complications. Many open questions remain about why this occurs. Data suggest that the physical location of fat and the overall health of fat dramatically influence disease risk; for example, higher concentrations of visceral relative to subcutaneous adipose tissue are associated with greater metabolic risks. As such, understanding the determinants of the location and health of adipose tissue can provide insight about the pathological consequences of obesity and can begin to outline targets for novel therapeutic approaches to combat the obesity epidemic. Although age and sex hormones clearly play roles in fat distribution and location, much remains unknown about gene regulation at the level of adipose tissue or how genetic variants regulate fat distribution. In this review, we discuss what is known about the determinants of body fat distribution, and we highlight the important roles of sex hormones, aging, and genetic variation in the determination of body fat distribution and its contribution to obesity-related comorbidities.