Sexual dimorphism of body composition

Tear film stability in children: Age and sex associations explored through non-invasive tear break-up time

PURPOSE

The stability of the tear film is crucial for maintaining good ocular health. Its assessment provides valuable insights into paediatric eye conditions. This study investigates the stability of the tear film in children and its association with predictive factors such as age and sex, for a better understanding of tear film dynamics in a paediatric population.

METHODS

A cross-sectional study was conducted in a semi-urban area in northern Portugal. Tear film stability was evaluated using non-invasive tear break-up time (NIBUT) measured with Tearscope Plus. The evaluation was conducted subjectively, with measurements obtained exclusively in the right eye. The mean of three consecutive measures of the NIBUT was considered in the statistical analysis.

RESULTS

A total of 2094 children (1072 females, 1022 males), with a mean age of 8.6 ± 1.3 years, were included. It was found a mean NIBUT of 14.8 ± 5.4 s (s), with no statistically significant difference between females (14.9 ± 5.4 s) and males (14.7 ± 5.4 s) (p = 0.407). Around 20 % of the children had a NIBUT < 10 s, and about 7 % had a NIBUT ≤ 5 s. A significant increase in NIBUT with age during the middle childhood stage (6 to 11 years old) was also found (p = 0.019), with NIBUT increasing from 14.1 ± 5.7 s in 6-year-olds to 16.3 ± 4.8 s in 11-year-olds (p = 0.006). However, when results were separated by the participants' sex, only the male group showed statistically significant differences (p = 0.021).

CONCLUSIONS

A significant increase in NIBUT was found during the middle childhood stage, primarily driven by male participants. These findings underscore the importance of considering age and sex in assessing tear film stability in paediatric populations.

Sex-specific variations in body pressure distribution across different sleep surfaces and positions

This study examines the impact of sex on body pressure distribution in supine, prone, and side sleeping positions on three surfaces: a pressure mattress, a sleeping mattress, and a combination of a sleeping bag and a sleeping mattress. Twenty participants (10 males and 10 females) were evaluated using a pressure-sensing system to measure pressure on key body regions depending on the sleep position. The results show that using a sleeping mat alone or combined with a sleeping bag significantly reduced body pressure in all positions. Males exerted higher pressure on the head, shoulders, and torso, while females showed a more even pressure distribution across these regions. Significant interactions were observed between body regions, sex, and surface type, emphasising the importance of considering anatomical differences when designing sleep systems. These findings have practical implications for improving comfort and reducing pressure-related injuries, especially in hospitals and outdoors.

Body Composition Characteristics of Elite Senior and Under 23 Australian Sprint Kayakers

The aim of this study was to compare body composition characteristics of elite senior and U23 sprint kayak athletes and report body composition changes during the COVID-19-interrupted preparation for the Tokyo 2020 Summer Olympics. A total of 32 Australian kayakers (Men: 20 (Senior = 13, U23 = 7); Women: 12, (Senior = 5, U23 = 7)) undertook body composition assessment using dual-energy X-ray absorptiometry (DXA) from 2017 to 2021. The first DXA assessment for each athlete was used for a cross-sectional analysis to compare senior and U23 sprint kayak athletes. Of the thirty-two kayakers, five senior men kayakers had repeat DXA scans over the data collection period which were used to monitor longitudinal changes in body composition. Senior men kayak athletes were heavier than U23 athletes (p = 0.017; 10.4 ± 1.9 kg; d = 1.23) but had similar body composition. In contrast, body mass was not different between senior and U23 women kayak athletes (p = 0.187), however senior women athletes had a significantly higher lean body mass (LBM; p = 0.048; 5.1 ± 1.3 kg, d = 1.32) and lower body fat percentage (p = 0.011; -4.3 ± 0.8%, d = 1.82). The five senior men kayakers exhibited a non-significant decrease in fat mass (p = 0.774; 2.9 ± 3.0 kg, d = 0.97) and increase in LBM (p = 0.234; 2.2 ± 5.9 kg, d = 0.38) across the Olympic quadrennial with little change in body mass. Senior men kayak athletes while heavier, have similar body composition compared to their U23 counterparts, whereas senior women kayakers are similar in body mass but differ in body composition compared to their younger counterparts. The relative influence of maturation, specificity of training, or dietary strategies on the observed differences in body composition between senior and U23 men and women kayak athletes are currently unknown and warrant further investigation.

Influence of urbanization on morphometrics and extent of sexual size dimorphism of the African common toad Sclerophrys regularis in the Accra Plains of Ghana

A thorough understanding of the effects of urbanization on wildlife is essential for designing effective strategies to conserve and manage wild animal populations in cities. Although the Afro-tropical region is experiencing rapid urbanization, the effect of this on wildlife in the region remains understudied. Here, we compared morphometric traits and extent of sexual size dimorphism of the African common toad Sclerophrys regularis among rural, suburban and urban areas in the Accra Plains of Ghana. We analyzed the morphometric data using univariate and multivariate statistics. Our data revealed that body mass and body condition, but not body size of toads varied significantly along the urbanization gradient. Urban and rural males were significantly heavier and had significantly higher body condition index value (in better condition) than their suburban counterparts, while urban females were significantly heavier and in better body condition than their suburban counterparts. The urban males and suburban females had significantly wider mouths than their rural conspecifics. We also found significant differences in head volume and length of limbs among sites, but the response direction varied with sex. Allometric analysis showed negative allometry in all the measured morphometrics with respect to SVL at all the sites for both sexes, except for suburban females, which showed positive allometry in most of the measured morphometrics. The toads exhibited female-biased sexual dimorphism (SSD) in SVL, body mass and head volume, with the extent of SSD being strongest for the suburban population. The variable responses of male and female S. regularis to urbanization could be due to phenotypic plasticity in its life history. Our findings highlight the potential role of individual-level response metrics in enhancing wildlife monitoring and conservation in cities.

Sex Differences in Upper- and Lower-Limb Muscle Strength in Children and Adolescents: A Meta-Analysis

On average, adult men are physically stronger than adult women. The magnitude of this difference depends on the muscle tested, with larger sex differences observed in upper- than lower-limb muscles. Whether body region-specific sex differences in strength exist in children is unclear. The purpose of the current meta-analysis was to determine whether sex differences in muscle strength in children and adolescents differ between upper- and lower-limb muscles. Data were extracted from studies of participants aged ≤ 17 years who completed tests of maximal isometric or isokinetic strength of upper-limb muscles (e.g., elbow flexors and elbow extensors) or lower-limb muscles (e.g., knee extensors and ankle dorsiflexors). Participants were partitioned into three age groups: 5-10 years old, 11-13 years old, and 14-17 years old. The analysis included 299 effects from 34 studies. The total sample was 6634 (3497 boys and 3137 girls). Effect sizes of sex differences in upper- and lower-limb strength were g = 0.65 (95% confidence intervals (CI) [0.46, 0.84]) and 0.34 (95% CI [0.19, 0.50]) in 5-10-year-olds; g = 0.73 (95% CI [0.56, 0.91]) and 0.43 (95% CI [0.27, 0.59]) in 11-13-year olds; and g = 1.84 (95% CI [1.64, 2.03]) and 1.18 (95% CI [1.00, 1.37]) in 14-17-year-olds. Upper- and lower-limb strength were 17% and 8% greater in boys than girls when 5-10 years old, 18% and 10% greater when 11-13 years old, and 50% and 30% greater when 14-17 years old. Thus, boys are stronger than girls on average. This sex difference exists before puberty, increases markedly with male puberty, and is more pronounced in upper- than lower-limb muscles throughout development.

Sex differences in the lipid profiles of visceral adipose tissue with obesity and gonadectomy

In obesity, adipose tissue (AT) expansion is accompanied by chronic inflammation. Altered lipid composition in the visceral or gonadal white AT (GWAT) directly drive AT macrophage accumulation and activation to a proinflammatory phenotype. Sex steroid hormones modulate visceral versus subcutaneous lipid accumulation that correlates with metabolic syndrome, especially in men and postmenopausal women who are more prone to abdominal obesity. Prior studies demonstrated sex differences in GWAT lipid species in HFD-fed mice, but the role of sex hormones is still unclear. We hypothesized that sex hormone alterations with gonadectomy (GX) would further impact lipid composition in the obese GWAT. Untargeted lipidomics of obese GWAT identified sex differences in phospholipids, sphingolipids, sterols, fatty acyls, saccharolipids and prenol lipids. Males had significantly more precursor fatty acids (palmitic, oleic, linoleic, and arachidonic acid) than females and GX mice. Targeted lipidomics for fatty acids and oxylipins in the HFD-fed male and female GWAT stromal vascular fraction identified higher omega-6 to omega-3 free fatty acid profile in males and differences in PUFAs-derived prostaglandins, thromboxanes, and leukotrienes. Both obese male and female GWAT stromal vascular fraction showed increased levels of arachidonic acid-derived oxylipins compared to their lean counterparts. Bulk RNA-seq of sorted GWAT AT macrophages highlighted sex and diet differences in PUFA and oxylipin metabolism genes. These findings of sexual dimorphism in both stored lipid species and PUFA-derived mediators with diet and GX emphasize sex differences in lipid metabolism pathways that drive inflammation responses and metabolic disease risk in obesity.

Sexual dimorphism in the association of umbilical cord blood lipidome with abdominal fat in early childhood

BACKGROUND

Although the associations between cord blood lipidome and neonatal birth weight are established, it remains uncertain whether sexual dimorphism in fetal fat accumulation extends to the relationship between cord blood lipid profiles and neonatal abdominal fat compartments. Understanding these relationships could provide insights into early sex-specific differences in lipid metabolism.

METHODS

We conducted lipidomics of umbilical cord blood plasma samples (350 (46.6%) girls and 401 (53.4%) boys) from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort. Abdominal fat compartments-superficial subcutaneous adipose tissue (sSAT), deep SAT (dSAT), and intra-abdominal adipose tissue (IAT)-were quantified by magnetic resonance imaging within 2 weeks of birth in 239 subjects. Linear regression models were used to assess sex differences in lipid species associated with abdominal fat compartments.

RESULTS

Newborn girls had significantly higher superficial and deep subcutaneous adipose tissue volumes compared to boys, whereas intra-abdominal adipose tissue volumes were similar between sexes. In the pooled analysis, cord blood plasma lipids showed distinct associations with different fat depots: 38 lipid species were associated with sSAT, 4 with dSAT, and 38 with IAT. In sex-stratified analyses, 13 lipids were associated with sSAT in girls and 3 in boys, whereas dSAT showed associations with 45 lipids in boys but none in girls. These sex differences were primarily observed in ether-linked phospholipids and ceramides. Notably, no significant associations were observed between lipids and IAT in either sex, suggesting depot-specific sexual dimorphism in early life.

CONCLUSIONS

Our study reveals sexual dimorphism in the associations between cord blood lipidome and abdominal adiposity, suggesting depot-specific patterns in adipose tissue development and lipid metabolism in early life.

Impact of age, sex, body constitution, and the COVID-19 pandemic on the physical fitness of 38,084 German primary school children

Physical fitness (PF) is a vital health indicator, but many children do not meet the WHO physical activity guidelines. Low PF in children raises the risk of non-communicable diseases (NCDs) and negatively impacts their quality of life, a situation amplified during the COVID-19 pandemic. This study uses data from 38,084 German third-graders (7.8 to 9.4 years) across seven cohorts (school years 2017/18-2023/24) who participated in a statewide fitness evaluation program in the Federal State of Thuringia. We aimed to examine age, sex, and pandemic effects on endurance (6-minute run), coordination (star run), speed (20-meter linear sprint), lower limb power (powerLOW; standing long jump), upper limb power (powerUP; ball-push test), and static balance (one-legged stance with eyes closed). Data on height and mass was incorporated to clarify the task-specific impact of the body mass index (BMI) on performance. Our results corroborated reported age and sex effects, demonstrating linear development across the age range for all tests, and in static balance only, girls scored higher than boys. The relationship between BMI and task-specific performance revealed an inverted U-shaped function in weight-bearing tests (first four). Functions were steeper for boys than girls, implying a stronger BMI impact on performance for boys. BMI and age interaction suggest that being overweight may limit age-related performance benefits. Negative pandemic declines in endurance, coordination, powerLOW, and powerUP were more pronounced in "fitter" schools. In conclusion, task-specific performances should be interpreted considering age, sex, and body constitution. Pandemic-related performance declines emphasize the role of access to physical activity resources for all children.

Testosterone mediates life-history trade-offs in female mammals

Hormones mediate life-history trade-offs. In female mammals, such trade-offs have been studied predominantly in the contexts of oestrogen, progesterone and prolactin. We evaluate the hypothesis that prenatal and postnatal testosterone levels structure and regulate trade-offs in females involving components of reproduction and survival. This hypothesis is predicated on the observation that testosterone confers competition-related and survival-related benefits, but also reproduction-related costs, to female mammals. The hypothesis is supported by field and laboratory data from diverse non-human animals, and data from healthy women. Most broadly, relatively low testosterone level in females has been associated with earlier, faster and higher offspring production, greater attractiveness to males, and reduced dominance or competitiveness, whereas higher testosterone level is associated with delayed and reduced reproduction but increased dominance, status, aggression, and resource accrual. The magnitude of testosterone-mediated trade-offs is expected to depend upon the strength of female-female competition, which represents some function of species-specific ecology, behaviour and mating system. Testosterone-associated trade-offs have, until now, been virtually ignored in studies of female life history, reproductive physiology, evolutionary endocrinology, and female-limited disease, probably due to researcher biases towards conceptualizing androgens as hormones with effects mainly restricted to males.

Osteocalcin in Infancy and Early Childhood and Its Correlation With Later Growth and Body Composition: A Longitudinal Birth Cohort Study

BACKGROUND

Osteocalcin is a metabolic active hormone, which correlates positively with bone formation and inversely with body mass index and waist circumference in adults.

OBJECTIVES

To investigate whether osteocalcin in infancy and early childhood were related to childhood growth or body composition.

METHODS

A Swedish longitudinal birth cohort with blood samples from 551 children from birth until 5 years of age. Regular anthropometric measurements were carried out up to 8 years of age and dual-energy X-ray absorptiometry (DXA) scans were also performed at 8 years. The results included p-values and Spearman's rho (ρ).

RESULTS

Osteocalcin at 4 months of age correlated inversely and consecutively with weight from 4 to 24 months and to waist circumference from 6 to 24 months in boys. The correlations for girls were limited to weight at 4 months and waist circumference at 6 and 18 months (ρ < 0.3, p = 0.001 to 0.048). The boys' osteocalcin levels at 5 years correlated positively with their height and weight at 5 and 6.5 years (ρ < 0.3, p < 0.01). Meanwhile, the girls' osteocalcin at 3 years showed positive correlations to all weight and height measurements until 8 years of age (ρ < 0.3, p = 0.003 to 0.023). DXA data showed that the boys' osteocalcin at 5 years correlated with the fat-free mass index (FFMI) (ρ 0.212, p = 0.026) but not the fat mass index (FMI) at 8 years. The opposite was seen for the girls' osteocalcin at 3 years, which correlated with FMI (ρ 0.222, p = 0.020) but not FFMI.

CONCLUSION

Early levels of osteocalcin showed inverse correlations with later weight, height and body composition in infancy and positive correlations during childhood. The weak but consistent correlations suggest that osteocalcin carries information about future growth. Girls with high osteocalcin at 3 and 5 years had a larger fat mass at 8 years, while boys, in contrast, had a larger lean mass. These sex differences need to be further explored.

Which pathway of the possible sarcopenia algorithm of the AWGS 2019 guideline is the best in Korean community-dwelling older men and women?

OBJECTIVE

To compare the diagnostic accuracy of possible sarcopenia identification pathways, as suggested by Asian Working Group for Sarcopenia (AWGS) in 2019, by gender among Korean community-dwelling older adults.

DESIGN

Cross-sectional analysis of data from 2,129 community-dwelling adults (70-84 years, 50.4% men) enrolled in Korean Frailty and Aging Cohort Study.

METHODS

Based on AWGS 2019 guideline, possible sarcopenia was defined by low handgrip strength (HGS) or slow five-times chair stand test (5CST) time, referred to as "assessments." "Case-findings" (low calf circumference [CC], SARC-F ≥4, or SARC-CalF ≥11) were recommended for screening 'possible sarcopenia' before assessment. For the six 'possible sarcopenia' pathways (combining three case-finding and two assessment tools), area under the curve (AUC) and F1 score are compared.

RESULTS

For case-finding in men, CC demonstrated the highest AUC (0.657) and F1 score (0.504) for predicting sarcopenia compared with SARC-F and SARC-CalF (p <0.001, =0.001). Among men with low CC, ΔAUC between HGS and 5CST was not significant as assessment (p=0.079) (AUCs: 0.763 vs. 0.707; F1 scores: 0.713 vs. 0.650). For case-finding in women, SARC-CalF demonstrated the highest AUC (0.631) and F1 score (0.389) compared with CC and SARC-F (p=0.012, <0.001). Subsequently, ΔAUC between HGS and 5CST was not significant in women (p=0.069) (AUCs: 0.566 vs. 0.636; F1 scores: 0.387 vs. 0.514).

CONCLUSIONS

Based on AWGS 2019 guideline, CC in men and SARC-CalF in women was the best case-finding tool for community-dwelling older adults. After the best case-finding in each gender, two assessment pathways demonstrated insignificant difference in both genders.

BRIEF SUMMARY

For case-finding of possible sarcopenia, using calf circumference in older men and using SARC-CalF in older women demonstrated the highest diagnostic accuracy for predicting sarcopenia. After the best case-finding in each gender, two assessment pathways (handgrip strength and five-times chair stand test) of possible sarcopenia demonstrated insignificant difference in both genders.

Intermittent fasting as a dietary intervention with potential sexually dimorphic health benefits

Intermittent fasting (IF) has proven to be a feasible dietary intervention for the wider population. The recent increase in IF clinical trials highlights its potential effects on health, including changes in body composition, cardiometabolic status, and aging. Although IF may have clinical applications in different populations, studies suggest there may be sex-specific responses in parameters such as body composition or glucose and lipid metabolism. Here, the existing literature on IF clinical trials is summarized, the application of IF in both disease prevention and management is discussed, and potential disparities in response to this type of diet between men and women are assessed. Moreover, the potential mechanisms that may be contributing to the sexually dimorphic response, such as age, body composition, tissue distribution, or sex hormones are investigated. This review underscores the need to further study these sex-specific responses to IF to define the most effective time frames and length of fasting periods for men and women. Tailoring IF to specific populations with a personalized approach may help achieve its full potential as a lifestyle intervention with clinical benefits.

Artificial Intelligence and Identification of the Deceased: a Narrative Review With Implications in Forensic Science

Identification of the dead is of utmost importance in mass disasters, war crimes, and forensic examinations. The biological profile, established by a forensic anthropologist is one the necessary steps involved in the identification of the dead. Several parameters can be estimated such as sex, age, stature, biogeographical affinity, and DNA profile of the unknown person. It is crucial to estimate these parameters of identification which may narrow down the investigation process. On the other hand, Artificial Intelligence (AI) in the modern world is showing magical uses in different fields. This communication aims to highlight the uses of AI tools for predicting parameters such as sex, age, stature, biogeographical affinity, and DNA profile of unknown persons with more accuracy and in less time. A literature search was conducted using databases PubMed, Scopus, Web of Science, and ScienceDirect for analyzing the use of artificial intelligence, machine learning, and deep learning algorithms for establishing the biological profile in disaster victim identification (DVI) and forensic casework. Moreover, this research foresees a paradigm shift in investigative techniques as technology advances, highlighting the convergence of AI and anthropological ideas for an improved understanding of the biological profiles of unknown deceased individuals.

DXA-Measured Total and Regional Body Composition in Female Athletes with a Physical Impairment

Background/Objectives: In recent years, awareness has been growing regarding the needs of female athletes with physical impairments. Despite the importance from both health and performance perspectives of assessing body composition in this athletic population, there is limited literature focusing on this topic. This study explored whole-body and regional three-compartment body composition in female athletes with a physical impairment to assess the impact of impairment and sex on body composition parameters in this population. Methods: Twenty female athletes with a physical impairment were pair-matched by age with an able-bodied female athlete and a male athlete with a comparable physical impairment. All athletes underwent whole-body scanning with dual-energy X-ray absorptiometry. Results: Female athletes with physical impairments showed body composition changes including higher amounts of fat mass, particularly in the lower body regions. Among athletes with a physical impairment, sex showed an independent effect on whole-body composition, with females showing higher fat mass and lower lean mass and bone mineral content compared with males, especially in the legs. Conclusions: Female athletes with physical impairments had a distinct body composition profile, characterized by sex-specific distribution of body tissue at the regional level. Nutritional and training strategies aimed at optimizing body composition in female athletes with physical impairments should be specifically tailored to meet the needs of this athletic population.

Association of Sociodemographic Variables and Healthy Habits with Body and Visceral Fat Values in Spanish Workers

Background and Objectives: The accumulation of fat in the body, especially visceral fat, is associated with various cardiometabolic conditions such as diabetes mellitus and fatty liver. The reasons for the accumulation of this fat are diverse. Some studies, also in the working population, have shown a clear association between sociodemographic variables and health habits with scales that assess overweight and obesity. This study aims to determine how certain sociodemographic variables, such as age, gender, and socioeconomic level, as well as certain healthy habits like physical activity and tobacco consumption, affect the levels of body and visceral fat. Materials and Methods: We conducted a descriptive and cross-sectional study involving 8590 Spanish workers. The percentage of body and visceral fat was measured using a bioimpedance analysis with a Tanita DC 430MA device. Results: Both the average values and the prevalence of elevated body and visceral fat increase with age and decrease with social class and lower levels of physical activity. These values are higher in smokers. A multivariate analysis shows that the variables most influential in increasing the risk of high levels of both body and visceral fat are age and low levels of physical activity. Conclusions: The profile of a person at high risk of having elevated body and visceral fat levels is an older male with a low socioeconomic status who smokes and leads a sedentary lifestyle.

Relationship between muscle power, muscle volume and limb length in healthy male and female adolescents

Objective

Muscle power is essential for the activities of daily living. Muscle power production depends on numerous factors such as muscle size and length, muscle architecture and fiber type and varies with age during growth. The association between muscle power output during a jump and lower limb muscle volume and length in adolescents is largely unknown. This study determined the relationships between muscle power developed during a countermovement jump with lower limb muscle volume and length in adolescents aged between 16 and 19 years.

Methods

Forty healthy adolescent males (n = 20) and females (n = 20) aged 16 to 19 years underwent a counter-movement jump (CMJ) test. Muscle power (MP) during the jump was calculated using the Gomez-Bruton equation. Lower limb muscle volume (MV) and length were calculated in both sexes using anthropometric methods. Pearson correlation was used to assess the associations between variables. Independent-sample t-tests were used to compare anthropometric and muscle performance data between males and females. Cohen's d was used to determine the size of the differences.

Results

There were differences in all anthropometric variables between males and females (p < 0.001). CMJ height (d = 4.45; p = 0.001) and MP (d = 4.74; p = 0.001) were greater in males than in females (p < 0.001). These differences persisted when jump performance was normalized to the MV (d = 1.05; p = 0.01) and length (d = 4.07; p = 0.001). There were correlations between MV and MP for males and females, with a significant correlation between limb length and MP for males (r = 0.55; p = 0.002).

Conclusions

This study indicates that MV and length are associated with MP production during a CMJ in adolescents aged between 16 and 19 years, suggesting that these factors may be important determining factors for vertical jumping performance during adolescence. The sex-differences in jump performance variables persisted after normalization by MV and length, suggesting that MV and length did not entirely explain the sex difference in muscle power output during a CMJ.

The type of sport, but not sex, impacts body composition and metabolic response to a complete weight loss-weight regain episode in weight cycling athletes: results from the WAVE study

Athletes may engage in weight cycling-successive episodes of weight loss and weight (re)gain-for performance reasons, but risk metabolic adaptations and regaining more fat that was lost (fat overshoot). This study aimed to assess the influence of a complete weight cycling episode on body composition, thermoregulation, and metabolism in athletes, considering sex and the type of sport practiced. Forty-eight athletes (28 males, 20 females) engaged in combat (n = 23), strength (n = 12), or endurance (n = 13) sports were examined under three experimental conditions (weight maintenance, weight loss, weight (re)gain) during a weight cycling episode using their habitual strategies. Body composition (dual-energy X-ray absorptiometry), core body temperature (telemetric temperature sensor), energy expenditure and substrate oxidation at rest and during moderate exercise (indirect calorimetry), and energy intake (48 h food record) were assessed. Overall, athletes lost 4.4 ± 2.3% body weight, 12.2 ± 10.6% fat mass, and 2.6 ± 2.3% fat-free mass (p < 0.001). All variables returned to baseline values during the regain period, and a higher fat mass regain was observed in endurance than combat athletes (p < 0.01). During weight loss, a transient increase in lipid and decrease in carbohydrate oxidation occurred at rest and during exercise (p < 0.001). Energy expenditure and core body temperature remained unchanged across the three experimental conditions, and no specific sex effect was observed. Overall, no apparent body weight nor fat overshoot was observed in athletes after a complete weight cycling episode. Nonetheless, the greater fat mass gain in endurance, compared with combat athletes, highlights a need for further specific long-term studies in this population. Clinical Trial registration: NCT04107545.

Relationship of irisin and apelin levels with sarcopenia and body composition in community-dwelling older adults: a paired case-control study

Irisin and apelin levels continue to decrease with age, and although many previous studies have explored their association with sarcopenia and body composition, there is still a paucity of evidence relating to them in community-dwelling elderly populations. The aim of this study was to provide new evidence for the association of irisin and apelin with sarcopenia in older adults. This case-control study included 80 individuals with sarcopenia and 80 individuals without sarcopenia. The definition of sarcopenia was based on the Asian Working Group for Sarcopenia 2019 criteria. Plasma levels of irisin and apelin were measured using an enzyme-linked immunosorbent assay. Conditional logistic regression analysis was performed to estimate odds ratios (ORs) and 95% CIs. The sarcopenia group exhibited significantly lower levels of irisin (73.75 ± 30.97 ng/mL vs. 131.15 ± 88.38 ng/mL, p < 0.001) and apelin (21.51 ± 14.89 ng/mL vs. 27.87 ± 14.41 ng/mL, p = 0.007) compared to the control group. Increased levels of irisin (OR, 0.98, 95% CI, 0.97-0.99) and apelin (OR, 0.97, 95% CI, 0.95-0.99) were associated with a decreased risk of sarcopenia. In women, irisin was positively associated with body mass index, intracellular water (ICW), extracellular water (ECW), total water (TW), protein, mineral, fat, fat-free mass, skeletal muscle mass (SMM), percentage body fat, waist circumference, visceral fat area, and basal metabolic rate. Apelin was positively associated with ICW, ECW, TW, protein, and SMM (all p < 0.05). In men, positive correlations were found between irisin, apelin, and handgrip strength (all p < 0.05). Receiver operating characteristic analysis showed that irisin and apelin had moderate predictive power in identifying sarcopenia. Plasma irisin and apelin were lower than in controls in elderly patients with sarcopenia, and elevated levels of irisin and apelin were associated with a reduced risk of sarcopenia. In addition, irisin and apelin levels are associated with body composition and irisin showed a stronger ability to predict sarcopenia in women.

Variation in diurnal cortisol patterns among the Indigenous Shuar of Amazonian Ecuador

OBJECTIVES

The hypothalamic-pituitary-adrenal (HPA) axis and its primary end product, the glucocorticoid cortisol, are major components of the evolved human stress response. However, most studies have examined these systems among populations in high-income settings, which differ from the high pathogen and limited resource contexts in which the HPA axis functioned for most of human evolution.

METHODS

We investigated variability in diurnal salivary cortisol patterns among 298 Indigenous Shuar from Amazonian Ecuador (147 males, 151 females; age 2-86 years), focusing on the effects of age, biological sex, and body mass index (BMI) in shaping differences in diurnal cortisol production. Saliva samples were collected three times daily (waking, 30 minutes post-waking, evening) for three consecutive days to measure key cortisol parameters: levels at waking, the cortisol awakening response, the diurnal slope, and total daily output.

RESULTS

Age was positively associated with waking levels and total daily output, with Shuar juveniles and adolescents displaying significantly lower levels than adults (p < .05). Sex was not a significant predictor of cortisol levels (p > .05), as Shuar males and females displayed similar patterns of diurnal cortisol production across the life course. Moreover, age, sex, and BMI significantly interacted to moderate the rate of diurnal cortisol decline (p = .027). Overall, Shuar demonstrated relatively lower cortisol concentrations than high-income populations.

CONCLUSIONS

This study expands the documented range of global variation in HPA axis activity and diurnal cortisol production and provides important insights into the plasticity of human stress physiology across diverse developmental and socioecological settings.

Sexually dimorphic ATF4 expression in the fat confers female stress tolerance in Drosophila melanogaster

Metabolic differences between males and females have been well documented across many species. However, the molecular basis of these differences and how they impact tolerance to nutrient deprivation is still under investigation. In this work, we use Drosophila melanogaster to demonstrate that sex-specific differences in fat tissue metabolism are driven, in part, by dimorphic expression of the Integrated Stress Response (ISR) transcription factor, ATF4. We found that female fat tissues have higher ATF4 activity than their male counter parts under homeostatic conditions. This dimorphism was partly due to a female bias in transcript abundance of specific ATF4 splice isoforms. We found that the canonical sex determinants transformer (tra) and doublesex (dsx) drive such dimorphic ATF4 transcript abundance. These differences persist in a genetic model of nutrient deprivation, where female animals showed greater resistance to lethality than males in an ATF4-dependent manner. These results suggest that higher ATF4 activity confers higher tolerance to stress in females. Together, our data describe a previously unknown facet of ISR signaling wherein sexual identity of adipose tissue confers differential stress tolerance in males and females. Since energy storage mechanisms are known to be dimorphic and have been linked to ATF4 regulation, our studies provide a mechanistic starting point for understanding how sexual identity influences metabolic disease outcomes.

Disparities in Evaluation, Treatment, and Outcomes of Pediatric Knee Injuries

Similar to other fields, there is growing evidence of disparities in pediatric sports medicine. For children and adolescents with knee injuries, disparities persist along the lines of sex, gender, race, ethnicity, insurance, socioeconomic status, and other determinants. These factors influence the evaluation, treatment, and outcomes for a variety of knee pathologies, including anterior cruciate ligament ruptures, meniscus tears, osteochondritis dissecans, cartilage injuries, and tibial spine fractures. Inequities in care may have long-term functional and psychosocial implications. Additional research is necessary to further elucidate the etiology of these disparities, raise patient and community voices, and design interventions so that equitable care is delivered to every patient.

Effects of Nonnutritive Sweeteners on the BMI of Children and Adolescents: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Prospective Cohort Studies

The effect of nonnutritive sweeteners (NNSs) on the body mass index [BMI (in kg/m2)] of children and adolescents remains unclear despite rising consumption. Detailed systematic evaluations are warranted. We aimed to summarize evidence on NNS consumption and BMI sex- and age-specific absolute changes (kg/m2) in pediatric populations, by NNS type, study design, duration, analysis type, conflicts of interest (COI), geographical region, age, sex, and baseline BMI. We searched randomized controlled trials (RCTs) and prospective cohort studies in children (2-9 y), adolescents (10-24 y), and young adults (20-24 y). Pooled estimates derived from random-effects meta-analysis for BMI changes, and the evidence quality was evaluated overall and by subgroup. From 2789 results, we included 4 RCTs [n = 1372; mean follow-up = 42.6 wk (standard deviation = 18.4); 2 (50%) with COI], and 8 prospective cohort studies [n = 35,340; median follow-up 2.5 y (interquartile range = 1.7-6.3), 2 (25%) with COI]. No identified studies evaluated NNS in food, NNS beverages compared with water, or participants aged 20-24 y. Random allocation to NNS beverages (25-2400 mg/d, from beverages) showed less BMI gain [mean difference = -0.114 kg/m2 (95% confidence interval [CI]: -0.207, -0.021); I2 = 87.02%] compared with sugar-sweetened beverages (SSBs). Stratified estimates resulted in less BMI gain in adolescents, participants with baseline obesity, consumers of mixed NNS, longer trials, and trials without COI. Pooled estimates from prospective cohorts showed a nonsignificant association between NNS beverages and BMI gain [0.05 kg/m2 (95% CI: -0.03, 0.13); I2 = 75.06%; per daily 355 mL serving]. Stratified estimates remained consistent. Removing studies with COI attenuated estimates. Evidence had low to moderate quality. In summary, pooled results from RCTs comparing NNS beverages compared with SSBs showed less BMI gain in adolescents with obesity. Meta-analyses of long-term cohort studies did not display a significant association between NNS beverages and BMI changes. This trial was registered at PROSPERO as CRD42022352284.

Body composition and perceived stress levels in transgender individuals after one year of gender affirming hormone therapy

Introduction

Higher stress levels are linked to increased body fat and decreased bone density, effects that can be exacerbated by lifestyle choices. This is particularly relevant for transgender and gender diverse (TGD) individuals, who often face additional stress from transphobia and social stigma. However, there is limited research on how stress affects body composition and bone health in TGD individuals, particularly in relation to gender-affirming hormone therapy (GAHT). This study examines the impact of perceived stress on these factors in TGD individuals before and after one year of GAHT, compared to a cisgender control group.

Methods

The study assessed 181 individuals, including 74 TGD participants (44 assigned female at birth [AFAB] and 30 assigned male at birth [AMAB]) and 107 controls (56 AFAB and 51 AMAB). Fifty-seven TGD participants completed follow-up one year after starting GAHT. Data collected included clinical history, blood tests, body composition, bone density, and quality of life assessments (Patient Health Questionnaire-9 [PHQ-9] and Perceived Stress Scale [PSS]).

Results

After one year of GAHT, TGD AFAB individuals showed a bone mineral density (BMD) similar to cisgender AMAB individuals, while TGD AMAB individuals' BMD remained significantly lower than cisgender controls. TGD AFAB individuals experienced increases in muscle strength (+8% from baseline), while TGD AMAB individuals showed a 24% increase in fat mass from baseline and an approximate 8% reduction in lean mass. PSS and PHQ scores, initially higher in TGD individuals, did not change significantly after one year of GAHT. A significant correlation was found between body fat percentage and PHQ and PSS scores at baseline and one year after GAHT, respectively.

Discussion

These findings reveal a complex relationship between GAHT, body composition, and perceived stress in TGD individuals, highlighting the need for further research on stress and health outcomes in this population.

Physical Activity Reduces Metabolic Risk via Iron Metabolism: Cross-National Evidence Using the Triglyceride-Glucose Index

Purpose: Studies suggest that the triglyceride-glucose index (TyG) is a novel and comprehensive marker of metabolic health. While most research indicates that increased physical activity (PA) is linked to improved metabolic health, some studies argue that the previous markers may not fully capture this relationship. This study uses TyG as a marker of metabolic health to examine the association between PA and TyG. Methods: Data are from cross-sectional surveys in three large population studies in China and the United States: CHARLS, CHNS, and NHANES. Regression models were applied to analyze the relationship between PA and TyG, with covariates adjusted in a stepwise manner. Stratified analysis was used to explore this relationship among different population groups, and, since it has been suggested that iron metabolism plays an important role in metabolic health, it was used as a mediating variable to construct a mediation model for analysis and discussion. Results: Higher PA was significantly associated with lower TyG levels across all three databases (p < 0.001), and this relationship remained robust after full adjustment for covariates. This negative association was more pronounced in older males (over 45 years). Iron metabolism also mediated this relationship, with mediation proportions ranging from 10% to 12.5%. Conclusions: There is a significant inverse association between PA and TyG, suggesting a link between increased PA and metabolic health, with iron metabolism moderating this relationship, especially among older males.

Association between Weight-Adjusted Waist Index and Depression in NAFLD: the modulating roles of sex and BMI

BACKGROUND

The Weight-Adjusted Waist Index (WWI) is a novel indicator of obesity that accurately reflects body composition. However, the association between WWI and depression in patients with non-alcoholic fatty liver disease (NAFLD) remains unclear. This study aims to explore this relationship through a nationally representative cross-sectional analysis.

METHODS

This study included adult participants diagnosed with NAFLD from NHANES 2017-2020. WWI was calculated as the waist circumference (cm) divided by the square root of body weight (kg). NAFLD diagnosis relied on vibration-controlled transient elastography (VCTE) with a controlled attenuation parameter (CAP) exceeding 248 dB/m to indicate hepatic steatosis. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), with scores ≥ 10 indicating the presence of major depression.

RESULTS

After adjusting for all covariates, a significant positive association was found between WWI and depression in NAFLD (OR = 1.725, 95% CI: 1.442-2.063, p < 0.00001), with a dose-response relationship indicated by restricted cubic spline analysis. The association was stronger in men and lean/normal weight NAFLD patients. Adjusting further for BMI did not alter these findings (OR = 1.643, 95% CI: 1.357-1.989, p < 0.00001). BMI's association with depression was negated after adjusting for WWI.

CONCLUSIONS

WWI had a positive association with depression in NAFLD, independent of BMI. This association was more pronounced in men and lean/normal weight NAFLD. These findings suggest that WWI may be a novel indicator of depression in NAFLD and potentially valuable in depression prevention.

Association between myopia and sleep duration among primary school students in minority regions of Southwest China: a school-based cross-sectional research

OBJECTIVE

To investigate the relationship between sleep duration and myopia among primary school students in minority regions of Southwest China.

METHODS

The school-based, cross-sectional study was conducted from October 2020 to January 2021. All participants underwent a comprehensive ocular examination and completed a questionnaire on demographic characteristics, ophthalmological history and major environmental factors for myopia. Spherical equivalent (SE) and ocular biometric parameters were measured after cycloplegia, with myopia being defined as SE ≤-0.5 D (Diopter). Multivariate regression models were used to examine the association of sleep duration with myopia, SE and axial length (AL).

RESULTS

A total of 857 students from grades 2 to 4 were included in the analysis, of which 63.6% were myopic and 62.0% belonged to ethnic minorities. Boys had a slightly higher prevalence of myopia compared with girls (66.7% vs 60.6%, p=0.06). Myopic students had longer AL, deeper anterior chamber depth and thinner central corneal thickness compared with non-myopic students (all p<0.05). There was no significant association between sleep duration and myopia in both boys and girls (p=0.319 and 0.186, respectively). Moreover, girls with a sleep duration of 8-9 hour/day had higher SE and shorter AL compared with those with less than 8 hour/day of sleep (β=0.41 and -0.32, respectively, all p<0.05).

CONCLUSION

This cross-sectional study did not find a significant association between sleep duration and myopia. However, it suggests that 8-9 hours of sleep per day may have a protective effect on SE progression and AL elongation in girls. Future studies with objectively measured sleep duration are needed to validate the findings.

Impact of maternal high-fat diet on offspring gut microbiota during short-term high-fat diet exposure in mice

Alterations in the gut microbiome have been linked to obesity, with maternal high-fat diet (HF) playing a role in shaping offspring microbiome composition. However, the sex-specific responses to maternal HF diet and the impact of subsequent dietary challenges remain unclear. This study investigated the effects of maternal HF diet on offspring gut microbiota structure and predicted functional profile in response to short-term postnatal HF diet exposure with a focus on sex-specific responses. Female and male offspring of maternal control (C) diet or maternal HF diet were weaned onto C diet or HF diet. Offspring were euthanized at 13 weeks of age and cecal contents were collected for bacterial taxonomic profiling. Maternal HF diet reduced α-diversity, notably in male offspring weaned onto HF diet. Sex-specific differences were observed in the gut microbial composition and predicted functional potential. Furthermore, the influence of maternal diet on bacterial community structure and functional potential varied depending on postnatal diet. Maternal HF diet led to increased relative abundance of Corynebacterium in female offspring and decreased abundance of Akkermansia and Roseburia in male offspring. These findings underscore the sexually dimorphic nature of maternal HF diet effects on gut microbiota composition and function, with implications for developmental programming and metabolic health.

An Association Between Left-Hand Digit Ratio (2D:4D) and Anthropometric Indexes in Chinese Children and Adolescents Aged 8-15 Years in Bengbu City

OBJECTIVES

The digit ratio (2D:4D) is a possible marker of prenatal hormone exposure. The purpose of this study was to explore the relationships between digit ratio (2D:4D) and anthropometric indexes in Chinese children and adolescents.

METHODS

This study is a cross-sectional study. A school-based survey among 685 children and adolescents aged 8-15 years were conducted by stratified cluster sampling. The length of index finger (2D) and ring finger (4D) of the left hand, height, sitting height (ST), weight, chest circumference (CC), waist circumference (WC), hip circumference (HC), and abdominal skinfold thickness (AST) were measured. Pearson correlation and multivariate linear regression were used to analyze associations between 2D:4D and above indexes.

RESULTS

In girls, 2D:4D was positively related to WC, AST, waist-to-height (WHtR), waist-to-hip ratio (WHR) after adjusting for ages (p < 0.05). The WC, AST, WHtR, and WHR among girls with 2D:4D ≥ 1 were significantly higher than those among girls with 2D:4D < 1, respectively (p < 0.05). However, there was no correlations between digit ratio (2D:4D) and above anthropometric indexes in boys (p > 0.05).

CONCLUSIONS

The 2D:4D was related to anthropometric indexes in girls, which suggests that the maternal prenatal hormone exposure might be related to the anthropometric indexes of their female offspring.

Bioelectrical Impedance Analysis Demonstrates Reliable Agreement with Dual-Energy X-ray Absorptiometry in Identifying Reduced Skeletal Muscle Mass in Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease and Hypertension

Background/Objectives: Body composition (BC) affects the risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD) and hypertension (HTN). Currently, dual-energy X-ray absorptiometry (DEXA) is considered the gold standard for assessing BC, even though it has some limitations, including immobility, ionizing radiation, and patient weight restrictions. The aim of the study was to evaluate the correlations of BC parameters measured by bioelectrical impedance analysis (BIA) with those measured by DEXA in patients with MASLD and HTN. Methods: Overall, 78 patients with MASLD and HTN underwent the following study procedures: compilation of an anamnesis, physical examination of a patient, laboratory tests, abdominal ultrasound, BIA, DEXA, and anthropometric measurements. Results: The agreement between BIA and DEXA in diagnosing reduced skeletal muscle mass (SMM) in patients with MASLD and HTN was moderate (kappa values were 0.440 and 0.404 in males and females, respectively). Significant strong direct correlations were found between fat mass (FM) and body fat percentage measured by BIA with corresponding measurements by DEXA (p < 0.001 for both). The area under the receiver operating characteristic curves (AUC) of SMM to body weight ratios calculated using BIA data were 0.834 and 0.929 for reduced appendicular SMM determined by DEXA in males and females with MASLD and HTN, respectively. Conclusions: In conclusion, BIA is an easy-to-use and widely available tool for assessing SMM and FM in patients with MASLD and HTN, demonstrating reliable agreement with DEXA measurement results and completely free of its limitations.

Sex differences in upper and lower strength and their association with body composition among university students

PURPOSE

Sex strongly influences physical performance throughout adolescence, and excess fat mass is associated with several health and performance impairments. This study aimed to evaluate whether variations in strength between men and women dependent on lean mass and body fat content.

METHODS

This cross-sectional, quasi-experimental, non-probabilistic study involved 44 university students (22 men and 22 women, aged 19-29). Handgrip strength (HGS) was measured using an adjustable handgrip dynamometer, body composition was assessed using bioimpedance, and countermovement jumps (CMJ) were measured using a force platform. Data were analyzed using ANOVA to compare HGS and CMJ based on body mass, and the Pearson correlation coefficient was applied to examine the relationships between grip strength, body composition, and jump test performance.

RESULTS

Strength is significantly higher in men compared to women, as is countermovement jump. The strength of women corresponded to over 50% of that of men, whereas the quantity of lean mass in women corresponded to 55% of that of men. We found a significant relationship between strength and lean mass.

CONCLUSION

This study supports the idea that both upper- and lower-body strengths are strongly influenced by lean mass, thereby contributing to sex differences. The primary factor in body composition that explains the disparities in HGS and CMJ between sexes is the proportion of fat mass to lean mass. Finally, the sex disparities observed between body composition and strength depend on lean mass content.

Sexual Dimorphism in the Musculoskeletal System: Sex Hormones and Beyond

Mounting evidence indicates that whereas some fundamental aspects of bone cell differentiation and function are similar in females and males, there is a clear contribution of sex/gender on the effects of signaling molecules on bone mass and strength and, consequently, on the effects of pharmacologic approaches to treat skeletal disorders. However, until recently, most studies were designed and performed using only 1 sex, resulting in a scarcity of published information on sexual dimorphism of the musculoskeletal system, including the mandible/masticatory muscles and the axial and appendicular bones and skeletal muscles. Further, it is now recognized that scientific rigor requires the study of both males and females. Therefore, there is an increasing need to understand the molecular and cellular basis for the differential outcomes of genetic manipulations and therapeutic agent administration depending on the sex of the experimental animals. Studies have shown higher muscle mass, cancellous bone mass, and long bone width in males compared with females as well as different traits in the pelvis and the skull, which are usually used for gender identification in forensic anthropology. Yet, most reports focus on the role of sex hormones, in particular, the consequences of estrogen deficiency with menopause in humans and in ovariectomized animal models. In addition, emerging data is starting to unveil the effects of gender-affirming hormonal therapy on the musculoskeletal system. We summarize here the current knowledge on the sex/gender-dependent phenotypic characteristics of the bone and skeletal muscles in humans and rodents, highlighting studies in which side by side comparisons were made.

Sex Differences in Energy Metabolism: A Female-Oriented Discussion

The purpose of this review is to delineate aspects of energy metabolism at rest and during exercise that may be subject to sex differences and the potential underlying mechanisms involved. It focuses on distinct aspects of female physiology with an oriented discussion following the reproductive life stages of healthy, eumenorrheic females, including premenopausal time frames, pregnancy, perimenopause, and menopause. Finally, this review aims to address methodological challenges surrounding sexual dimorphism in energy metabolism investigations and confounding factors in this field. During resting conditions, females tend to have higher rates of non-oxidative free fatty acid clearance, which could contribute to lower respiratory exchange ratio measures. At the same time, carbohydrate energy metabolism findings are mixed. In general, females favor lipid energy metabolism during moderate-intensity exercise, while men favor carbohydrate energy metabolism. Factors such as age, dietary intake, genetics, and methodological decisions confound study findings, including properly identifying and reporting the menstrual cycle phase when female subjects are eumenorrheic. Pregnancy presents a unique shift in physiological systems, including energy metabolism, which can be observed at rest and during exercise. Changes in body composition and hormonal levels during the post-menopausal period directly impact energy metabolism, specifically lipid metabolism. This change in physiological state factors into the evidence showing a reduction in our understanding of sex differences in lipid metabolism during exercise in older adults. This review reveals a need for a focused understanding of female energy metabolism that could help exercise and nutrition professionals optimize female health and performance across the lifespan.

Thigh muscle by CT images as a predictor of mortality in patients with newly diagnosed colorectal cancer

This study aimed to evaluate the prognostic value of thigh muscle assessed by CT images to predict overall mortality in patients with colorectal cancer (CRC). This was a multicenter cohort study including adults (≥ 18 years old) newly diagnosed with CRC, who performed a diagnostic computed tomography (CT) exam including thigh regions. CT images were analyzed to evaluate skeletal muscle (SM in cm2), skeletal muscle index (SMI in cm2/m2), and skeletal muscle density (SMD in HU). Muscle abnormalities (low SM, SMI, and SMD) were defined as the values below the median by sex. Kaplan-Meyer curves and hazard ratios (HRs) for low SM, SMI and SMD were evaluated for overall mortality, stratified by sex. A total of 257 patients were included in the final analysis. Patients' mean age was 62.6 ± 12.1 years, and 50.2% (n = 129) were females. In males, low thigh SMI was associated with shorter survival (log-rank P = .02). Furthermore, this low thigh SMI (cm2/m2) was independently associated with higher mortality rates (HR adjusted 2.08, 95% CI 1.03-4.18). Our additional findings demonstrated that low SMD was independently associated with overall mortality among early-stage patients (I-III) (HR adjusted 2.78, 95% CI 1.26-6.15).

Correlation between Breastfeeding, Maternal Body Mass Index, and Childhood Obesity

Breast milk is a unique and highly beneficial source of nutrition for infants. It contains a wide range of nutrients that are specifically tailored to meet the specific needs of a growing infant. On the other hand, obesity is a major health issue that affects people around the world. The aim of this study is to investigate the relationship between breastfeeding and child BMI and the role of maternal BMI, which may influence this relationship. This study revealed that a longer duration of exclusive breastfeeding was associated with a decrease in the prevalence of overweight children. Additionally, the research found that children born to overweight or obese women had a higher probability of being overweight or obese themselves. Considering that mothers with a higher pre-pregnancy body weight are more likely to have children with a higher BMI, it is important that they receive information about the advantages of breastfeeding for a minimum of 6 months for both themselves and their children. Additionally, they should be offered ongoing support, to encourage them to start breastfeeding and continue with it beyond this period.

Evidence of gene-nutrient interaction association with waist circumference, cross-sectional analysis

BACKGROUND AND AIMS

Waist circumference (WC) is a significant indicator of body adiposity and is associated with increased mortality and morbidity of cardiovascular diseases. Although, single nutrient intake and candidate genes were previously associated with WC. Little is known about WC association with overall diet quality, genetic risk score and gene-nutrient interaction. This study aims to investigate the influence of overall diet quality and multiple WC-associated single nucleotide polymorphisms on WC. In addition to investigating gene-nutrient interaction association with WC.

METHODS

This study explored cross-sectional data from two large sample-size studies, to provide reproducible results. As a representation of the UK population, the Airwave Health Monitoring Study (n = 6,502) and the UK-Biobank Cohort Study (n = 171,129) were explored for factors associated with WC. Diet quality was evaluated based on the Mellen Index for Dietary Approaches to Stop Hypertension (Mellen-DASH). The genetic risk score for WC (GRS-Waist) was calculated by screening the population genotype for WC-associated single nucleotide polymorphisms. Multivariate linear regression models were built to explore WC association with diet quality and genetic risk score. Gene-nutrient interaction was explored by introducing the interaction term (GRS-Waist X Mellen-DASH score) to multivariate linear regression analysis.

RESULTS

The prevalence of high WC (Female > 80 cm, Male > 94 cm) was 46.5% and 51.7% in both populations. Diet quality and genetic risk score of WC were significantly associated with WC. There was no evidence of interaction between GRS-Waist, DASH diet scores and nutrient intake on WC.

CONCLUSION

This study's findings provided reproducible results on waist circumference association with diet and genetics and tested the possibility of gene-nutrient interaction. These reproducible results are successful in building the foundation for using diet and genetics for early identification of those at risk of having high WC and WC-associated diseases. In addition, evidence on gene-diet interactions on WC is limited and lacks replication, therefore our findings may guide future research in investigating this interaction and investigating its application in precision nutrition.

Using multiomics to explore the weight differences between genders in Muscovy ducks

Sexual dimorphism in poultry, especially in Muscovy ducks, is a proven phenomenon characterized by significant differences in body weight, growth patterns, and gene expression between male and female individuals. However, there is a dearth of research on the candidate genes and mechanisms underlying these weight differences. We selected 301 Muscovy ducks and recorded their weekly body weights from birth. We utilized 3 non-linear growth models (Logistic, Bertalanffy, and Gompertz) to fit the growth curve of Muscovy ducks, it was found that the logistic model was the most suitable model for describing the growth curve of Muscovy ducks. The results from the logistic model showed that the inflection point of male Muscovy ducks occurred at a later age, and they had a heavier mature body weight than female Muscovy ducks. At 10 wk of age, we collected Muscovy duck breast muscle tissues for transcriptome sequencing (RNA-seq). To exclude the impact of weight difference, 185 differentially expressed genes (DEGs), such as PPAR, FABP3, PLIN1, and FOXO1, were screened. These DEGs were predominantly enriched in terms related to mitochondria, lipids, and nucleic acids. In addition, the gut microbiota has the ability to influence host physiology through the regulation of multiple processes, including playing a crucial role in host muscle growth and development. We randomly selected male and female Muscovy ducks for 16S rRNA sequencing analysis of their cecal microbiota. The results showed that there were significant differences in the composition of cecal microbiota between male and female Muscovy ducks. At the genus level, the relative abundance of Enterenecus and CAG_269 were lower in males compared to females, while Lawsonibacter, Parabacteroides_B, Streptococcus, UBA2658, Caccousia, and Butyricimonas were higher in males than in females. In summary, this study provides a scientific theoretical basis for revealing the different growth patterns of male and female Muscovy ducks, and offers explanations from both the molecular level and microbiological perspectives.

Multivariate genetic architecture reveals testosterone-driven sexual antagonism in contemporary humans

Sex difference (SD) is ubiquitous in humans despite shared genetic architecture (SGA) between the sexes. A univariate approach, i.e., studying SD in single traits by estimating genetic correlation, does not provide a complete biological overview, because traits are not independent and are genetically correlated. The multivariate genetic architecture between the sexes can be summarized by estimating the additive genetic (co)variance across shared traits, which, apart from the cross-trait and cross-sex covariances, also includes the cross-sex-cross-trait covariances, e.g., between height in males and weight in females. Using such a multivariate approach, we investigated SD in the genetic architecture of 12 anthropometric, fat depositional, and sex-hormonal phenotypes. We uncovered sexual antagonism (SA) in the cross-sex-cross-trait covariances in humans, most prominently between testosterone and the anthropometric traits - a trend similar to phenotypic correlations. 27% of such cross-sex-cross-trait covariances were of opposite sign, contributing to asymmetry in the SGA. Intriguingly, using multivariate evolutionary simulations, we observed that the SGA acts as a genetic constraint to the evolution of SD in humans only when selection is sexually antagonistic and not concordant. Remarkably, we found that the lifetime reproductive success in both the sexes shows a positive genetic correlation with anthropometric traits, but not with testosterone. Moreover, we demonstrated that genetic variance is depleted along multivariate trait combinations in both the sexes but in different directions, suggesting absolute genetic constraint to evolution. Our results indicate that testosterone drives SA in contemporary humans and emphasize the necessity and significance of using a multivariate framework in studying SD.

Agreement and differences between the equations for estimating muscle and bone mass using the anthropometric method in recreational strength trainees

Introduction

The interest in estimating muscle mass (MM) and bone mass (BM) has grown in the sporting arena, and more specifically in recreational strength trainees, leading to the creation of different strategies to assess them. The aims were: 1) to investigate the agreement between different MM and BM formulas, and the muscle-bone index (MBI), and to establish the differences between them, in a healthy young adult population; and 2) to analyze if there are differences between males and females in the comparison of MM, BM and MBI formulas.

Methods

This study followed a descriptive cross-sectional design. A total of 130 adult active recreational strength trainees were evaluated according to the procedures described by the International Society for the Advancement in Kinanthropometry (ISAK). Estimations were made in kilograms of MM and BM by following the equations by different authors.

Results

The results showed significant differences between the values obtained by all the MM and BM formulas in the general sample (p < 0.001), and by the majority of formulas for male and female samples. In the general sample, Lin's coefficient indicated a strong agreement between Kerr, Lee, and Poortmans' MM estimation equations (concordance correlation coefficient (CCC) = 0.96-0.97). However, when stratifying by sex, this agreement persisted only in males (CCC = 0.90-0.94), in contrast with a lack of agreement observed in females (CCC < 0.90). Discrepancies in bone mass agreement were noted both in the general sample (CCC < 0.15) and when stratified by sex (CCC < 0.12).

Conclusions

In general, differences were found between the values reported by the MM and BM formulas in recreational strength trainees, without an agreement between them. Sex was shown to significantly influence the differences found. The practical implications are that when comparing an individual with reference tables, other studies, or if analyzing an individual's evolution, the same estimation equation should be used, as they are not interchangeable.

Association between Variants of the TRPV1 Gene and Body Composition in Sub-Saharan Africans

In humans, the transient receptor potential vanilloid 1 (TRPV1) gene is activated by exogenous (e.g., high temperatures, irritating compounds such as capsaicin) and endogenous (e.g., endocannabinoids, inflammatory factors, fatty acid metabolites, low pH) stimuli. It has been shown to be involved in several processes including nociception, thermosensation, and energy homeostasis. In this study, we investigated the association between TRPV1 gene variants, sensory perception (to capsaicin and PROP), and body composition (BMI and bioimpedance variables) in human populations. By comparing sequences deposited in worldwide databases, we identified two haplotype blocks (herein referred to as H1 and H2) that show strong stabilizing selection signals (MAF approaching 0.50, Tajima's D > +4.5) only in individuals with sub-Saharan African ancestry. We therefore studied the genetic variants of these two regions in 46 volunteers of sub-Saharan descent and 45 Italian volunteers (both sexes). Linear regression analyses showed significant associations between TRPV1 diplotypes and body composition, but not with capsaicin perception. Specifically, in African women carrying the H1-b and H2-b haplotypes, a higher percentage of fat mass and lower extracellular fluid retention was observed, whereas no significant association was found in men. Our results suggest the possible action of sex-driven balancing selection at the non-coding sequences of the TRPV1 gene, with adaptive effects on water balance and lipid deposition.

Mendelian randomization unraveled: gender-specific insights into obesity-related phenotypes and colorectal cancer susceptibility

Objective

Evidence has been increasingly pointing towards a potential link between phenotypes related to obesity and the incidence of colorectal cancer. However, confirming this as a direct causal connection remains elusive. This investigation aims to elucidate the causative links between obesity-associated phenotypes and the incidence of colorectal cancer.

Methods

Employing the Two Sample Mendelian Randomization (TwoSampleMR) R package, analyses were conducted using Mendelian randomization (MR) to discern potential causative links between obesity categories sourced from both the Institute for Education and University (IEU) Open GWAS Project and Zenodo, and colorectal tumors (data obtained from IEU Open GWAS and FinnGen). For primary evaluations, the study utilized the Wald ratio and the Inverse Variance Weighting (IVW) methods, while the MR-Egger approach was integrated for sensitivity assessment. Bidirectional Mendelian Randomization (Bidirectional MR), as well as Linkage Disequilibrium (LD) Score Regression with well-imputed HapMap3 single nucleotide polymorphisms (SNPs), were additionally executed. Sensitivity assessments entailed IVW, MR-Egger methodologies to assess heterogeneity and pleiotropy, along with a leave-one-out strategy. Instrumental variables were chosen judiciously based on predetermined P-value thresholds and F-statistics.

Results

Results from MR evaluations did not identify a clear causative link between BMI and colorectal malignancy. Conversely, both measures of obesity, the Waist-Hip Ratio (WHR) and its adjusted form for BMI (WHRadjBMI), displayed a connection to increased risk of colorectal cancer, especially prominent among female subjects. Reverse MR analyses dismissed potential reverse causality between colorectal malignancies and obesity. A significant genetic interplay was observed between WHR, WHRadjBMI, and colorectal cancer instances. Ensuing MR probes spotlighted inflammatory bowel ailment as a protective factor, while salad intake was indicated as a potential risk concerning colorectal malignancies. Sensitivity reviews, which included tests for both pleiotropy and heterogeneity, validated the robustness of the MR findings.

Conclusion

Findings from this research indicate that specific obesity-related parameters, notably WHR and WHRadjBMI, carry a causal relationship with an elevated colorectal cancer risk. The impact is distinctly more evident among females. Such insights might be pivotal for public health deliberations, hinting that individuals boasting a high WHR might necessitate intensified colorectal cancer screenings.

Sexual dimorphism of adiposity and fat distribution among children and adolescents (8-18 year olds) from Poland

OBJECTIVES

The study aimed to analyze the sexual dimorphism of total body fat [BF%] and fat distribution among 8-18 year olds from Poland.

METHODS

The study included 2175 participants, divided into sex and age groups. Waist and hip circumferences, the thickness of six skinfolds, waist-to-hips ratio [WHR], the ratio of abdominal-to-suprailiac skinfolds, and the limb-to-trunk adiposity index were analyzed. Fat percentage were measured with a body composition analyzer (Tanita) with accuracy 0.1%. The Mollison's Index [MI] was used for calculating sexual dimorphism.

RESULTS

The value of MI for the WHR and its components (waist and hip circumferences) was negative (the boys were characterized by higher values of these parameters). The magnitude of the sex differences was lower in the younger age groups and the highest in the oldest groups. For adiposity [BF%], the average values were higher in females. In the younger age groups, girls had thicker skinfolds compared to boys, and this tendency was also observed in the older age groups, except for abdominal and suprailiac skinfolds. The values of the analyzed adiposity indicators also represented a tendency toward central allocation of fat tissue in boys.

CONCLUSIONS

In conclusion, sexual dimorphism of fat distribution and adiposity could be detected as early as 7 years of age. These differences can be identified using simple anthropometric methods, which are relatively cheap and easy to use, particularly in the field setting and large populations. The observation of changes in these features in children should be a recommended procedure aimed at early detection of overweight, obesity, as well as normal weight obesity or other metabolic disorders.

Does the association between adiposity measures and pre-frailty among older adults vary by social position? Findings from the Tromsø study 2015/2016

INTRODUCTION

Pre-frailty provides an ideal opportunity to prevent physical frailty and promote healthy ageing. Excess adiposity has been associated with an increased risk of pre-frailty, but limited studies have explored whether the association between adiposity measures and pre-frailty varies by social position.

METHODS

We used data from the seventh survey of the Tromsø Study (Tromsø7) conducted in 2015-2016. Our primary sample consisted of 2,945 women and 2,794 men aged ≥ 65 years. Pre-frailty was defined as the presence of one or two of the five frailty components: low grip strength, slow walking speed, exhaustion, unintentional weight loss and low physical activity. Adiposity was defined by body mass index (BMI), waist circumference (WC), fat mass index (FMI) and visceral adipose tissue (VAT) mass. Education and subjective social position were used as measures of social position. Poisson regression with robust variance was used to assess the association between adiposity measures and pre-frailty, and the interaction term between adiposity measures and social position measures were utilised to explore whether the association varied by social position.

RESULTS

In our sample, 28.7% of women and 25.5% of men were pre-frail. We found sub-multiplicative interaction of BMI-defined obesity with education in women and subjective social position in men with respect to development of pre-frailty. No other adiposity measures showed significant variation by education or subjective social position. Regardless of the levels of education or subjective social position, participants with excess adiposity (high BMI, high WC, high FMI and high VAT mass) had a higher risk of pre-frailty compared to those with low adiposity.

CONCLUSION

We consistently observed that women and men with excess adiposity had a greater risk of pre-frailty than those with low adiposity, with only slight variation by social position. These results emphasize the importance of preventing excess adiposity to promote healthy ageing and prevent frailty among all older adults across social strata.

Ancient eukaryotic protein interactions illuminate modern genetic traits and disorders

All eukaryotes share a common ancestor from roughly 1.5 - 1.8 billion years ago, a single-celled, swimming microbe known as LECA, the Last Eukaryotic Common Ancestor. Nearly half of the genes in modern eukaryotes were present in LECA, and many current genetic diseases and traits stem from these ancient molecular systems. To better understand these systems, we compared genes across modern organisms and identified a core set of 10,092 shared protein-coding gene families likely present in LECA, a quarter of which are uncharacterized. We then integrated >26,000 mass spectrometry proteomics analyses from 31 species to infer how these proteins interact in higher-order complexes. The resulting interactome describes the biochemical organization of LECA, revealing both known and new assemblies. We analyzed these ancient protein interactions to find new human gene-disease relationships for bone density and congenital birth defects, demonstrating the value of ancestral protein interactions for guiding functional genetics today.

Association between time of assessment within a school year and physical fitness of primary school children

The dissociation of effects of age, time of assessment and cohort is a well-known challenge in developmental science. We examined effects of time of assessment in the school year on children's physical fitness using data from 75,362 German third-graders from seven cohorts. Children were tested once either in the first or second school term of third grade. Tests examined cardiorespiratory endurance (6-min run), coordination (star-run), speed (20-m sprint), lower (standing long jump) and upper (ball-push test) limbs muscle power, and flexibility (stand-and-reach test). We estimated the effect of time of assessment using a regression discontinuity design specified in a linear mixed model with random factors child and school and adjusted for age, sex, and cohort effects. Coordination, speed, and upper limbs muscle power were better in second compared to first school term, with boys exhibiting a larger increase of upper limbs muscle power than girls. There was no evidence for changes in cardiorespiratory endurance, lower limbs muscle power, and flexibility between assessments. Previously reported age and sex effects as well as secular fitness trends were replicated. There is thus evidence for improvement of some physical fitness components beyond age and cohort effects that presumably reflects the benefit of physical activity in physical education and other settings. Effects of assessment time should be taken into consideration in performance-based grading or norm-based selection of children.

Effects of gender-affirming hormone therapy on body fat: a retrospective case‒control study in Chinese transwomen

BACKGROUND

There is insufficient research on how gender-affirming hormone therapy (GAHT) affects body fat modifications in transwomen from China. It is unclear whether hormone therapy affects the prevalence of obesity and blood lipid levels within this population. The current research aimed to assess how GAHT and treatment duration had an impact on the change in and redistribution of body fat in Chinese transwomen.

METHODS

This study included 40 transwomen who had not received GAHT and 59 who had. Body fat, blood lipid, and blood glucose levels were measured. GAHT is mainly a pharmacologic (estrogen and anti-androgen) treatment. The study also stratified participants based on the duration of GAHT to assess its impact on body fat distribution. The duration of GAHT was within one year, one to two years, two to three years, or more than three years.

RESULTS

After receiving GAHT, total body fat increased by 19.65%, and the percentage of body fat increased by 17.63%. The arm, corrected leg, and leg regions showed significant increases in fat content (+ 24.02%, + 50.69%, and + 41.47%, respectively) and percentage (+ 25.19%, + 34.90%, and + 30.39%, respectively). The total visceral fat content decreased (-37.49%). Based on the diagnostic standards for a body mass index ≥ 28 or total body fat percentage ≥ 25% or 30%, the chance of developing obesity did not change significantly. Blood glucose levels significantly increased (+ 12.31%). Total cholesterol levels (-10.45%) decreased significantly. Fat changes in those who received GAHT for one to two years were significantly different from those who did not receive GAHT.

CONCLUSION

After receiving GAHT, total body fat and regional fat increased in Chinese transwomen, and the body fat distribution changed from masculine to feminine, especially during the first two years. However, neither the increase in total body fat percentage nor the decrease in visceral fat content didn't bring about significant changes in the incidence of obesity, nor did triglycerides or low-density lipoprotein-cholesterol.

Sarcopenia Prevalence among Hospitalized Patients with Severe Obesity: An Observational Study

Background: Sarcopenic obesity (SO) is the combination of excess fat, skeletal muscle and muscular strength/function deficit. The ESPEN/EASO have proposed new diagnostic criteria, but the SO prevalence in patients with severe obesity remains to be established. The aim of this study was to establish the SO prevalence in a large cohort of inpatients with obesity, considering sex, age, BMI, type, and number of concomitant diseases. Methods: Patient data of both genders aged between 18 and 90 years with a body mass index (BMI) of ≥30 kg/m2 underwent hospital evaluation including bioelectrical impedance analysis (BIA) and handgrip strength (HS). QoL scores were obtained by the Psychological General Well-Being Index questionnaire. The study was approved by the institutional Ethic Committee. Results: Among the 3858 patients, 444 (11.51%) exhibited a strength deficit, while 3847 (99.71%) had skeletal muscle mass deficit. The prevalence of SO was then 11.48%, with higher rates in women (12.39%), in individuals aged >70 years (27%), and in those reporting a 'poor' QoL (12.6%). No significant difference in SO prevalence was found when stratifying by BMI (30-40 kg/m2 vs. >40 kg/m2, p = 0.1710). In SO patients, osteoarticular diseases (57%), hypertension/heart failure (38%), type 2 diabetes mellitus (34%), and obstructive sleep apnea (32%) were the more frequent comorbidities. Conclusions: The application of ESPEN/EASO-SO criteria in a cohort of inpatients with severe obesity revealed 11.48% SO prevalence, which was associated with age (particularly > 70 years), gender (women), but not BMI, as determinants. Disease staging and QoL screening may improve the identification of SO high-risk patients.

The role of various physiological and bioelectrical parameters for estimating the weight status in infants and juveniles cohort from the Southern Cuba region: a machine learning study

OBJECTIVE

The search for other indicators to assess the weight status of individuals is important as it may provide more accurate information and assist in personalized medicine.This work is aimed to develop a machine learning predictions of weigh status derived from bioimpedance measurements and other physical parameters of healthy infant juvenile cohort from the Southern Cuba Region, Santiago de Cuba.

METHODS

The volunteers were selected between 2002 and 2008, ranging in age between 2 and 18 years old. In total, 393 female and male infant and juvenile individuals are studied. The bioimpedance parameters are obtained by measuring standard tetrapolar whole-body configuration. A classification model are performed, followed by a prediction of other bioparameters influencing the weight status.

RESULTS

The results obtained from the classification model indicate that fat-free mass, reactance, and corrected resistance primarily influence the weight status of the studied population. Specifically, the regression model demonstrates that other bioparameters derived from impedance measurements can be highly accurate in estimating weight status.

CONCLUSION

The classification and regression predictive models developed in this work are of the great importance for accessing to the weigh status with high accuracy of younger individuals at the Oncological Hospital in Santiago de Cuba, Cuba.

Body composition and body fat distribution in tissue-specific insulin resistance and in response to a 12-week isocaloric dietary macronutrient intervention

BACKGROUND

Body composition and body fat distribution are important predictors of cardiometabolic diseases. The etiology of cardiometabolic diseases is heterogenous, and partly driven by inter-individual differences in tissue-specific insulin sensitivity.

OBJECTIVES

To investigate (1) the associations between body composition and whole-body, liver and muscle insulin sensitivity, and (2) changes in body composition and insulin sensitivity and their relationship after a 12-week isocaloric diet high in mono-unsaturated fatty acids (HMUFA) or a low-fat, high-protein, high-fiber (LFHP) diet.

METHODS

This subcohort analysis of the PERSON study includes 93 individuals (53% women, BMI 25-40 kg/m2, 40-75 years) who participated in this randomized intervention study. At baseline and after 12 weeks of following the LFHP, or HMUFA diet, we performed a 7-point oral glucose tolerance test to assess whole-body, liver, and muscle insulin sensitivity, and whole-body magnetic resonance imaging to determine body composition and body fat distribution. Both diets are within the guidelines of healthy nutrition.

RESULTS

At baseline, liver fat content was associated with worse liver insulin sensitivity (β [95%CI]; 0.12 [0.01; 0.22]). Only in women, thigh muscle fat content was inversely related to muscle insulin sensitivity (-0.27 [-0.48; -0.05]). Visceral adipose tissue (VAT) was inversely associated with whole-body, liver, and muscle insulin sensitivity. Both diets decreased VAT, abdominal subcutaneous adipose tissue (aSAT), and liver fat, but not whole-body and tissue-specific insulin sensitivity with no differences between diets. Waist circumference, however, decreased more following the LFHP diet as compared to the HMUFA diet (-3.0 vs. -0.5 cm, respectively). After the LFHP but not HMUFA diet, improvements in body composition were positively associated with improvements in whole-body and liver insulin sensitivity.

CONCLUSIONS

Liver and muscle insulin sensitivity are distinctly associated with liver and muscle fat accumulation. Although both LFHP and HMUFA diets improved in body fat, VAT, aSAT, and liver fat, only LFHP-induced improvements in body composition are associated with improved insulin sensitivity.

TRIAL REGISTRATION

NCT03708419 (clinicaltrials.gov).

Sex-related differences in the clinical presentation of multiple system atrophy

PURPOSE

To investigate sex-related differences in the clinical presentation of multiple system atrophy (MSA) through a literature review and an analysis of a retrospective cohort.

METHODS

The PubMed database was searched for articles including sex-related information in MSA. In a retrospective Innsbruck cohort, we investigated the baseline to last available follow-up clinical-demographic differences between men and women with MSA in a univariate fashion, followed by multivariable binary regression analysis.

RESULTS

The literature search yielded 46 publications with sex-related information in MSA. Most studies found comparable survival rates between the sexes, while some recent reports suggested a potential survival benefit for women, possibly due to initial motor onset and overall less severe autonomic failure compared to men. The retrospective Innsbruck MSA cohort comprised 56 female and 60 male individuals with a comparable median follow-up of 27 months. At baseline, female sex was independently associated with depression (odds ratio [OR] 4.7; p = 0.007) and male sex with severe orthostatic hypotension (OR 5.5; p = 0.016). In addition, at last follow-up, female sex was associated with the intake of central nervous system-active drugs (OR 4.1; p = 0.029), whereas male sex was associated with the presence of supine hypertension (OR 3.0; p = 0.020) and the intake of antihypertensive medications (OR 8.7; p = 0.001). Male sex was also associated with initiation of antihypertensive medications over the observation period (OR 12.4; p = 0.004).

CONCLUSION

The available literature and findings of the present study indicate sex-related differences in the clinical presentation of MSA and its evolution over time, highlighting the importance of considering sex in symptom exploration, therapeutic decision-making, and future clinical trial design.