Photonic Scanning Research Articles

Body composition in healthy singleton term infants using the three-dimensional photonic scanning method: A multicenter cross-sectional study

ObjectivesBody composition is an integral part of the nutritional assessment during infancy as it is closely related to future health. The three-dimensional photonic body surface scanning (3-DPS) method is a promising new technique for measuring body composition in children because of its advantages of easy operation, low cost, and no exposure to radiation. Using 3-DPS, this study aimed to illustrate the growth trajectories of body composition indicators during infancy according to sex and age. MethodsThis was a multicenter cross-sectional study. The body compositions of 9644 singleton term infants from four centers in Shandong Province, China, were assessed using 3-DPS. The data of 8769 healthy infants (52.0% boys), whose z scores of weight-for-length, length-for-age, and weight-for-age, according to World Health Organization standards, were in the range of –2 to 2, –3 to 3, and –3 to 3, respectively, were sampled to construct percentile curves of fat mass (FM), fat-free mass (FFM), FM percentage (FM%), FM index (FMI), and FFM index (FFMI) with the generalized additive model for location, scale, and shape method. ResultsPercentile charts for FM, FFM, FM%, FMI, and FFMI were developed based on age and sex. FM and FFM presented consistent trajectories with that of weight, with the fastest growth occurring at 1 to 3 mo of age. FM%, FMI, and FFMI increased with age, peaked at 6 mo, and gradually declined, which was consistent with the body mass index trend. All indicators, except for FFMI, were always significantly higher in boys than in girls ages 1 to 12 mo, indicating that sex differences in body composition existed mainly in FM rather than in lean body mass. ConclusionsThe body composition of healthy singleton term infants during infancy varies with age; boys may have more FM accumulation than girls.

Ultra‐Fast Photonic Digital Polymerase Chain Reaction based on N‐Heterocyclic Carbene Self‐Assembled Monolayer

AbstractA molecular diagnosis of the respiratory syncytial virus (RSV) without bulky and expensive instrumentation is of great importance for the early detection and prevention in a fast‐spreading pandemic. However, the current representative diagnostic methods have the limitation of being time‐consuming, cost, the processing time for polymerase chain reaction (PCR), and inaccurate for lateral flow assay (LFA), representatively. Herein, an integrated photonic digital PCR (dPCR) is developed with high‐velocity photonic scanner for in situ fluorescence detection by introducing the N‐heterocyclic carbene self‐assembled monolayer‐based Au film to prevent the quenching effect. The on‐site rapid molecular diagnostic platform shows the driving of 40 cycles in under 8 min and fluorescence scanning in under 7 min, resulting in a total analysis time within 15 min. In particular, the technology clearly demonstrates the classification of SARS‐CoV‐2 patients and healthy controls (99% in sensitivity, 98.6% in specificity, and 96.4% in accuracy with RdRp gene), comparing with standard RT‐qPCR. This platform can be utilized for prompt point‐of‐care molecular diagnostics in early diagnosis and large‐scale prevention of next pandemic spreading for upcoming infectious diseases and for the distinction diagnosis with other RSV.

The impact of body position on measurement of equine lumbar and hindquarter volume using 3-dimensional scans

Well-developed musculature is important for performance yet difficult to quantify. Recently, we validated infrared 3-dimensional (3-D) photonic scanning as an accurate measure of body volume and proxy for regional muscle mass in horses. Our current objective was to determine the impact of body position on measures of lumbar (LV) and hindquarter (HQV) volume. Anatomic markers were placed on 8 horses, positioned at: (1) four hooves square, (2) neck turned ~25°, (3) head raised mean 17 cm, (4) one hind hoof (HH) forward 14±5 cm, (5) a front and contralateral HH ~15 cm all offset, (6) one HH resting. A handheld Occipital Structure Sensor photonic scanner, iPad, Skanect and Materialise 3-Matic programs captured LV and HQV. Measured LV and HQV for whole, same and opposite-side with altered head positions and whole LV and HQV with altered HH positions were compared to volume standing square using repeated measures ANOVA. The volumes of the opposite-side or same-side with altered HH positions were compared to the corresponding side when square using a paired t test with multiple test correction (P<0.017). Head elevated negatively impacted measured left LV (-10% difference,P=0.1) compared to square, however, differences were not significant. Head turned did not impact measured LV. Resting HH significantly increased measured whole (18%,P=0.04) and same-side LV (49%,P=0.001) versus square but not the opposite-side LV. One HH forward (whole 16%,P=0.02; same-side 19%,P=0.01) or all offset (whole 14%,P=0.002; same-side 27%,P=0.0001) significantly increased measured whole or same-side LV versus square. Measured HQV was not impacted by head elevated or limb position but was 2% higher on the opposite-side of the turned head (P=0.01). We conclude that alterations in body position have minimal impact on measured HQV, whereas accurate assessment of LV requires horses stand squarely.

Deep-learning-assisted linearization for the broadband photonic scanning channelized receiver.

An autoencoder-residual (AE-Res) network is designated to assist the linearization of the wideband photonic scanning channelized receiver. It is capable of adaptively suppressing spurious distortions over multiple octaves of signal bandwidth, obviating the need for calculating the multifactorial nonlinear transfer functions. Proof-of-concept experiments indicate that the improvement of the third-order spur-free dynamic range (SFDR2/3) is 17.44 dB. Moreover, the results for real wireless communication signals demonstrate that the improvement of the spurious suppression ratio (SSR) is 39.69 dB and the reduction of the noise floor is ∼10 dB.

Concordância da autopercepção da imagem corporal com a análise de imagem corporal tridimensional de adolescentes

Abstract Objectives: to verify the agreement among adolescents’ perception of their own body image and the health professionals’ analysis based on three-dimensional body image and the inter-rater agreement. Methods: a cross-sectional study was carried out with 1,662 adolescents, aged 18 to 19 years old, from the 1997/98 birth cohort in São Luís, Maranhão. Self-perception of body image was assessed using the Stunkard’s body image scale. Three nutritionists evaluated the three-dimensional body image obtained by the Photonic Scanner (3D Body Scanner) and classified according to the Stunkard’s scale. The agreement between raters was verified by using weighted Kappa. Results: the analysis of agreement between raters in the general group and when stratified by sexwas considered moderate to good by Kappa. Regarding the intraclass correlation (ICC), good and excellent correlation values were observed both in the general group, males and females. There was a greater perception of overweight by all raters, when compared with the adolescents’ self-assessments. When stratified by sex, examiner 1 had the same perception as male self-assessments, as for females the perception of overweight was more frequent, as well as raters 2 and 3, for both sexes. Conclusion: agreement between raters and self-assessments was considered weak/moderate in Kappa and good/excellent in ICC.

The site of waist measurement impacts the estimation of visceral fat: results from three-dimensional photonic body scanning.

Currently, various protocols regarding the site of waist circumference (WC) measurement are in place. This study aimed to analyse the effect of the site of WC measurement on visceral adipose tissue (VAT) estimation. WC was obtained at 7 anatomical sites in 211 German volunteers (103 males) aged 23-81 years using three-dimensional photonic body scanning (PBS). At one site, WC was additionally measured by tape. The quantity of VAT was assessed by MRI. Models to estimate VAT based on WC were developed; the precision of the estimation is represented by R2. The influence of the applied method of WC assessment (tape v. PBS) on the estimations is reported. Results show that the amount of estimated VAT and the precision of VAT estimation were dependent on the site of measurement. VAT was estimated most precisely by WC taken at the level of the lowest rib (WCrib: R2 = 0·75 females; 0·79 males), the minimum circumference (WCmin: R2 = 0·75 females; 0·77 males) and at the narrowest part of the torso (WCnar: R2 = 0·76 females; 0·77 males), and least precisely by WC assessed at the top of iliac crest (WCiliac: R2 = 0·61 females; 0·60 males). VAT estimates based on WC obtained by PBS were smaller and estimations were slightly less precise compared to estimates based on tape measures. Our results indicate that the method and the site of waist measurement should be considered when estimating VAT based on WC. The implementation of a standardised protocol using either WCrib, WCmin or WCnar could improve the precision of VAT estimation.

Test-retest reliability and validity of body composition methods in adults.

Cost-effective and efficient body composition measurement devices that are reliable and valid are necessary for identifying health risk as well as for understanding the effectiveness of lifestyle interventions. The objective of this study was to evaluate the test-retest reliability and validity of three body composition measurement devices. Forty-nine adults (mean age (SD)=31.5 (10.7) y; BMI=23.5 (3.0) kg/m2 ) completed a reference air displacement plethysmography (ADP) measure, and duplicate measures using skinfold callipers (Lange), ultrasound (BodyMetrix A-mode) and a 3-dimensional photonic scanner (3DPS; Fit3D ProScanner). Skinfold thickness was measured at seven sites using callipers and ultrasound; percent body fat (%BF) was then estimated using population-specific algorithms. The 3DPS was used to measure body circumferences, and then %BF was estimated using its beta-software. While skinfold callipers showed poor absolute reliability (mean differences (Δ) [95% CI]=0.54% [0.22, 0.87], standard error of measurement (SEM)=0.63%), ultrasound and the 3DPS showed excellent absolute (Δ=0.17% [-0.25, 0.58], SEM=0.78%; and Δ=-0.01% [-0.43, 0.40], SEM=0.67%, respectively) and relative reliability (ICC2,1 =0.988 [0.979, 0.993]; and ICC2,1 =0.983 [0.968, 0.991], respectively). Compared to ADP (n=43), skinfold callipers underestimated %BF (Δ=-4.53 [-7.72, -1.34]; p=0.003), while ultrasound (Δ=-0.32 [-3.51, 2.87]; p=0.99) and the 3DPS (Δ=1.06 [-2.12. 4.26]; p=0.77) were not significantly different. Bland-Altman plots showed a minimal bias of ultrasound [95% limit of agreement (LOA)=-7.87, 7.23] and the 3DPS [95% LOA=-6.66, 8.79]. In conclusion, estimating %BF from subcutaneous fat measurements using ultrasound and body circumferences using a 3DPS may be reliable and valid methods that require minimal technician expertise.

Associations between relative body fat and areal body surface roughness characteristics in 3D photonic body scans\u2014a proof of feasibility

IntroductionA reliable and accurate estimate of the percentage and distribution of adipose tissue in the human body is essential for evaluating the risk of developing chronic and noncommunicable diseases. A precise and differentiated method, which at the same time is fast, noninvasive, and straightforward to perform, would, therefore, be desirable. We sought a new approach to this research area by linking a person’s relative body fat with their body surface’s areal roughness characteristics.Materials and methodsFor this feasibility study, we compared areal surface roughness characteristics, assessed from 3D photonic full-body scans of 76 Swiss young men, and compared the results with body impedance-based estimates of relative body fat. We developed an innovative method for characterizing the areal surface roughness distribution of a person’s entire body, in a similar approach as it is currently used in geoscience or material science applications. We then performed a statistical analysis using different linear and stepwise regression models.ResultsIn a stepwise regression analysis of areal surface roughness frequency tables, a combination of standard deviation, interquartile range, and mode showed the best association with relative body fat (R2 = 0.55, p < 0.0001). The best results were achieved by calculating the arithmetic mean height, capable of explaining up to three-quarters of the variance in relative body fat (R2 = 0.74, p < 0.001).Discussion and conclusionThis study shows that areal surface roughness characteristics assessed from 3D photonic whole-body scans associate well with relative body fat, therefore representing a viable new approach to improve current 3D scanner-based methods for determining body composition and obesity-associated health risks. Further investigations may validate our method with other data or provide a more detailed understanding of the relation between the body’s areal surface characteristics and adipose tissue distribution by including larger and more diverse populations or focusing on particular body segments.

Instantaneous frequency analysis of broadband LFM signals by photonics-assisted equivalent frequency sampling

We propose a photonics-assisted equivalent frequency sampling (EFS) method to analyze the instantaneous frequency of broadband linearly frequency modulated (LFM) microwave signals. The proposed EFS method is implemented by a photonic scanning receiver, which is operated with a frequency scanning rate slightly different from the repetition rate of the LFM signals. Compared with the broadband LFM signal analysis based on temporal sampling, the proposed method avoids the use of high-speed analog to digital converters, and the instantaneous frequency acquisition realized by frequency-to-time mapping is also simplified since real-time Fourier transformation is not required. Feasibility of the proposed method is verified through an experiment, in which frequency analysis of Kα-band LFM signals with a bandwidth up to 3 GHz is demonstrated with a moderate sampling rate of 100 MSa/s. The proposed method is highly demanded for analyzing the instantaneous frequency of broadband LFM signals used in radar and electronic warfare systems.

A Multidomain Approach to Assessing the Convergent and Concurrent Validity of a Mobile Application When Compared to Conventional Methods of Determining Body Composition.

Determining body composition via mobile application may circumvent limitations of conventional methods. However, the accuracy of many technologies remains unknown. This investigation assessed the convergent and concurrent validity of a mobile application (LS) that employs 2-dimensional digital photography (LS2D) and 3-dimensional photonic scanning (LS3D). Measures of body composition including circumferences, waist-to-hip ratio (WHR), and body fat percentage (BF%) were obtained from 240 healthy adults using LS and a diverse set of conventional methods—Gulick tape, bioelectrical impedance analysis (BIA), and skinfolds. Convergent validity was consistently high—indicating these methods vary proportionally and can thus reliably detect changes despite individual measurement differences. The span of the Limits of Agreement (LoA) using LS were comparable to the LoA between conventional methods. LS3D exhibited high agreement relative to Gulick tape in the measurement of WHR, despite poor agreement with individual waist and hip circumferences. In BF%, LS2D exhibited high agreement with BIA and skinfold methods, whereas LS3D demonstrated low agreement. Interestingly, the low inferred bias between LS3D and DXA using existing data suggests that LS3D may have high agreement with dual-energy x-ray absorptiometry. Overall, the suitability of LS2D and LS3D to replace conventional methods must be based on an individual user’s criteria.

Photonic scanning receiver for wide-range microwave frequency measurement by photonic frequency octupling and in-phase and quadrature mixing.

A photonic scanning receiver with optical frequency scanning and electrical intermediate frequency envelope detection is proposed to implement wide-range microwave frequency measurement. This system applies photonic in-phase and quadrature frequency mixing to distinguish and measure the signals in two frequency bands that mirror each other. Combined with the photonic frequency octupling technique, the proposed system has a frequency measurement range that is 16 times that of the sweeping range of the electrical signal source. Besides, optical frequency sweeping with up and down chirps is used to relax the requirement for precise synchronization between the sweeping source and the analog-to-digital converter. In the experiment, using an electrical sweeping local oscillator having a bandwidth of 1.75 GHz, the system achieves a frequency measurement range as large as 28 GHz. The measurement errors are kept within 24 MHz with an average error of 9.31 MHz.

Anthropometrics by Three-Dimensional Photonic Scanner in Patients with Obesity Before and After Bariatric Surgery.

We studied body composition by three-dimensional photonic scanning (3DPS) and metabolic biomarkers in a large ethnically diverse cohort of individuals with severe obesity before and after weight loss by Roux-en-Y gastric bypass (RYGB) or adjustable gastric banding (AGB) surgery. Male and female participants (n = 95) underwent 3DPS testing in the weeks preceding bariatric surgery (baseline), and 1year after either RYGB (n = 34) or AGB (n = 9). Principal component analysis showed that A1C and HDL cholesterol clustered with waist-to-hip ratio (WHR). Both RYGB and AGB surgeries led to similar improvements in A1C and lipids after 1year. RYGB led to greater decreases in body weight, and in most anthropometric measures, compared with AGB at 1year. However, after accounting for weight loss differences, RYGB and AGB groups did not differ in regional decreases in circumferences or volumes; the exception was a greater reduction in lean mass in RYGB compared with AGB. Distribution of weight loss, assessed by 3DPS, did not differ between RYGB and AGB, but surgery type predicted change in lean mass at 1year.

Multiple measures derived from 3D photonic body scans improve predictions of fat and muscle mass in young Swiss men.

Digital tools like 3D laser-based photonic scanners, which can assess external anthropometric measurements for population based studies, and predict body composition, are gaining in importance. Here we focus on a) systematic deviation between manually determined and scanned standard measurements, b) differences regarding the strength of association between these standard measurements and body composition, and c) improving these predictions of body composition by considering additional scan measurements. We analysed 104 men aged 19-23. Bioelectrical Impedance Analysis was used to estimate whole body fat mass, visceral fat mass and skeletal muscle mass (SMM). For the 3D body scans, an Anthroscan VITUSbodyscan was used to automatically obtain 90 body shape measurements. Manual anthropometric measurements (height, weight, waist circumference) were also taken. Scanned and manually measured height, waist circumference, waist-to-height-ratio, and BMI were strongly correlated (Spearman Rho>0.96), however we also found systematic differences. When these variables were used to predict body fat or muscle mass, explained variation and prediction standard errors were similar between scanned and manual measurements. The univariable predictions performed well for both visceral fat (r2 up to 0.92) and absolute fat mass (AFM, r2 up to 0.87) but not for SMM (r2 up to 0.54). Of the 90 body scanner measures used in the multivariable prediction models, belly circumference and middle hip circumference were the most important predictors of body fat content. Stepwise forward model selection using the AIC criterion showed that the best predictive power (r2 up to 0.99) was achieved with models including 49 scanner measurements. The use of a 3D full body scanner produced results that strongly correlate to manually measured anthropometric measures. Predictions were improved substantially by including multiple measurements, which can only be obtained with a 3D body scanner, in the models.

Deep neural network-assisted high-accuracy microwave instantaneous frequency measurement with a photonic scanning receiver.

A microwave instantaneous frequency measurement system with a photonic scanning receiver is proposed in which deep neural network (DNN)-assisted frequency estimation is used to deal with the system defects and improve the accuracy. The system performs frequency-to-time mapping by optical-domain frequency scanning and electrical-domain intermediate frequency envelop detection. Thanks to the optical frequency multiplication, the system can measure high frequency signals in a large spectral range. The DNN establishes an accurate mapping between the digital samples and real frequencies, based on which high-accuracy measurement is achieved. The measurement of signals from 43 to 52 GHz is experimentally demonstrated. Compared with the direct measurements, the DNN-assisted method achieves obviously reduced average errors of about 3.2 MHz.

Prediction of muscle mass in arms and legs based on 3D laser-based photonic body scans’ standard dimensions in a homogenous sample of young men

ABSTRACT Reliably identifying muscle mass from external anthropometric measurements can provide valuable information about a person’s health conditions and related outcomes. A potential tool for easily predicting muscle mass is three-dimensional (3D) body scans, but accurate validation data are missing. The aim of our study was to predict skeletal muscle mass (SMM) as assessed by Bioelectrical Impedance Analysis (BIA) from 3D body scanner data. We aimed to examine which 3D body scan standard parameters of the upper and lower limbs best predict skeletal muscle mass measured by BIA in a cross-sectional and homogenous sample of N = 100 young men. In both arms and legs, Spearman’s rank correlation coefficients with SMM were generally high for girths and volumes, and lower for lengths. The volumes of the forearm (R = 0.80–0.82) and calf (R = 0.87) correlated best with SMM. For the longitudinal follow-up of N = 45 young men, the Wilcoxon signed-rank test showed that, on average, the longitudinally followed-up increased in weight, height, BMI as well as relative/absolute fat mass. The best single predictors for individual differences in SMM were deltas for upper arm girth of both arms (adjusted R2 0.17 and 0.17) and deltas for calf girth of both legs (0.37 and 0.45). Although 3D body scan girth measures can predict SMM in upper and lower limbs satisfying, adding volumes and lengths to the equations increase the precision of the estimations fairly.

3 Dimensional photonic scans for measuring body volume and muscle mass in the standing horse.

Reasons for performing studyAlthough muscle mass strongly influences performance, there is currently no effective means to measure the 3-dimensional muscle mass of horses. We evaluated a 3-dimensional (3D) scanning methodology for its ability to quantify torso and hindquarter volumes as a proxy for regional muscle mass in horses.ObjectivesDetermine the repeatability of 3D scanning volume (V) measurements and their correlation to body weight, estimated body volume and muscle/fat ultrasound (US) depth.MethodsHandheld 3D photonic scans were performed on 16 Quarter Horses of known body weight 56 days apart (n = 32 scans) with each scan performed in duplicate (n = 32 replicates). Tail head fat, gluteal and longissimus dorsi muscle depths were measured using US. Processed scans were cropped to isolate hindquarter (above hock, caudal to tuber coxae) and torso (hindquarter plus dorsal thoracolumbar region) segments and algorithms used to calculate V. Torso and hindquarter volume were correlated with body weight and US using Pearson’s correlation and with estimated torso volume (50% body weight / body density) with Bland-Altman analysis.ResultsScans took 2 min with < 3.5% error for duplicate scans. Torso volume (R = 0.90, P< 0.001) and hindquarter volume (R = 0.82, P< 0.001) strongly correlated with body weight and estimated BV (R = 0.91) with low bias. Torso volume moderately correlated to mean muscle US depth (R = 0.4, P< 0.05) and tail head fat (R = 0.42, P< 0.01). Mean muscle US depth moderately correlated to body weight (R = 0.50, P< 0.01).Main limitations3D Scans determine body volume not muscle volume.ConclusionsThe hand-held 3D scan provided a rapid repeatable assessment of torso and hindquarter volume strongly correlated to body weight and estimated volume. Superimposition of regional scans and volume measures could provide a practical means to follow muscle development when tail head fat depth remain constant.

High-Resolution Three-Dimensional Photonic Scan-Derived Equations Improve Body Surface Area Prediction in Diverse Populations.

Equations for predicting body surface area (BSA) produce flawed estimates, especially for individuals with obesity. This study aimed to compare BSA measured by a three-dimensional photonic scanner (3DPS)with BSA predicted by six commonly cited prediction equations and to develop new prediction equations if warranted. The 3DPS was validated against manual measurements by breadth caliper for body thicknesses measured at three anatomical sites on a mannequin. BSA was derived from 3DPS whole-body scans of 67 males and 201 females, aged 18 to 83years, with BMI between 17.8 and 77.8 kg/m2 and varied races/ethnicities. Width and depth measurements by 3DPS and caliper were within 1%, except for hip, with an error of 1.8%. BSA3DPS differed from BSA predicted by each equation (P < 0.05), except for males by DuBois and DuBois (P = 0.60), Tikuisis (P = 0.27), and Yu (P = 0.45) and for females by Tikuisis (P = 0.70). The combined and sex-specific equations obtained by regressing ln(BSA) on ln(weight in kilograms [W]) and ln(height in meters [H]) are as follows (R2 and SEE correspond to ln[BSA]): combined, BSA3DPS = 0.03216 × W0.4904 × H0.3769 , R2 = 0.982, SEE = 0.021; males, BSA3DPS = 0.01624 × W0.4725 × H0.5231 ; and females, BSA3DPS = 0.01522 × W0.4921 × H0.5231 , R2 = 0.986, SEE = 0.019. New height and weight BSA equations improve BSA estimation in individuals withBMI ≥ 40and in African Americans, Hispanic Americans, and Asian Americans.

Anatomy and Histochemistry of Leaf and Stem of Brazilian Endemic Species Mollinedia clavigera Tul.

Abstract This study aimed to investigate the anatomy and histochemistry of Mollinedia clavigera leaves and stems through photonic microscopy and scanning electron microscopy. Noteworthy features of leaves were: presence of paracytic stomata on both surfaces; simple as well as bifurcate non-glandular trichomes; prismatic calcium oxalate crystals; flat-convex midrib with a central and two dorsal bundles; concave-convex petiole with a single vascular bundle in open archh. Stems were cylindrical and showed prismatic and styloid crystals in the pith. Histochemical analysis detected lipophilic and phenolic compounds, starch grains and lignified elements such as brachysclereids and fibers. These features may assist in future identifications and quality control of M. clavigera, avoid misidentification between other genus members, once species and genus studies are scarce.

Body height and waist circumference of young Swiss men as assessed by 3D laser-based photonic scans and by manual anthropometric measurements.

Overweight and obesity are considered among the major health concerns worldwide. The body mass index is a frequently used measure for overweight and obesity and is associated with common non-communicable diseases such as diabetes type II, cardiovascular diseases and certain cancers. However, the body mass index does not account for the distribution of body fat and relative fat to muscle mass. 3D laser-based photonic full body scans provide detailed information on various body circumferences, surfaces, and volumes as well as body height and weight (using an integrated scale). In the literature, body scans showed good feasibility, reliability, and validity, while also demonstrating a good correlation with health parameters linked to the metabolic syndrome. However, systematic differences between body scan derived measurements and manual measurements remain an issue. This study aimed to assess these systematic differences for body height, waist circumference, and body mass index using cross-sectional data from a homogenous sample of 52 young Swiss male volunteers. In addition to 3D laser-based photonic full body scans and correlative manual measurements, body fat distribution was assessed through bioelectrical impedance analysis. Overall, an excellent correlation was found between measurements of waist circumference and body mass index, and good correlation between body mass index and total fat mass, as well as between waist circumference and visceral fat mass as assessed by bioelectrical impedance analysis. Volunteers were shorter in height measured by body scan when compared to manual measurements. This systematic difference became smaller when volunteers stood in the scanner in a completely upright position with their feet together. Waist circumference was slightly smaller for manual measurements than for body scan derived values. This systematic difference was larger in overweight volunteers compared to leaner volunteers.

Evolution of total body and regional adiposity from late adolescence to early adulthood in a birth cohort study

BackgroundDifferences in total body and regional adiposity according to sex are observed from an early age, but these differences become more evident after puberty due to hormonal changes. We aimed to assess the evolution of total body and regional adiposity from 18 to 22 years of age and the associated sociodemographic and nutritional characteristics.MethodsIn total, 3274 individuals from the 1993 Pelotas birth cohort study followed up at 18 and 22 years of age. Measures of total body and regional adiposity were assessed using whole-body dual-energy X-ray absorptiometry (DXA) and the TC2 Three-Dimensional Photonic Scanner. We used fat mass index obtained from DXA as a measure of total body adiposity, and android and gynoid fat mass percentages (android or gynoid fat mass [kg]/total fat mass [kg])*100) as measures of regional adiposity. In addition, waist, hip and thigh circumferences from the photonic scanner were also used as measures of regional adiposity. We evaluated these measurements at 18 and 22 years of age by sex and estimated differences between them according to sociodemographic and nutritional characteristics.ResultsWhile men and women did not differ in terms of BMI, females exhibited a higher fat mass index, gynoid fat mass percentage, and hip and thigh circumferences; men exhibited higher android fat mass percentage and waist circumference at both time points. Increases in all body measurements from age 18 to 22 were observed in men and women, except for gynoid fat mass percentage, which decreased in both sexes. Socioeconomic position and race were the independent variables most associated with adiposity rising from age 18 to 22 in women, with black women and women of lower socioeconomic positions exhibiting larger increases in adiposity.ConclusionThere was an increase in adiposity and a centralization of body shape from late adolescence to early adulthood, indicating possible early risks for noncommunicable diseases in this cohort.