Nino Carlo Battistini

Cross-calibration of eight-polar bioelectrical impedance analysis versus dual-energy X-ray absorptiometry for the assessment of total and appendicular body composition in healthy subjects aged 21-82 years.

Aim: To calibrate eight-polar bioelectrical impedance analysis (BIA) against dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition in healthy adults. Research design: A cross-sectional study was carried out. Subjects: Sixty-eight females and 42 males aged 21-82 years participated in the study. Methods: Whole-body fat-free mass (FFM) and appendicular lean tissue mass (LTM) were measured by DXA; resistance ( R ) of arms, trunk and legs was measured by eight-polar BIA at frequencies of 5, 50, 250 and 500 kHz; whole-body resistance was calculated as the sum R of arms, trunk and legs. Results: The resistance index (RI), i.e. the height 2 /resistance ratio, was the best predictor of FFM and appendicular LTM. As compared with weight (Wt), RI at 500 kHz explained 35% more variance of FFM ( vs 0.57), 45% more variance of LTM arm ( vs 0.48) and 36% more variance of LTM leg ( vs 0.50) ( p < 0.0001 for all). The contribution of age to the unexplained variance of FFM and appendicular LTM was nil or negligible and the RI 2 sex interactions were either not significant or not important on practical grounds. The percent root mean square error of the estimate was 6% for FFM and 8% for LTM arm and LTM leg. Conclusion: Eight-polar BIA offers accurate estimates of total and appendicular body composition. The attractive hypothesis that eight-polar BIA is influenced minimally by age and sex should be tested on larger samples including younger individuals.

Accuracy of an eight-point tactile-electrode impedance method in the assessment of total body water.

Objective: To establish the accuracy of an eight-polar tactile-electrode impedance method in the assessment of total body water (TBW).Design: Transversal study.Setting: University department.Subjects: Fifty healthy subjects (25 men and 25 women) with a mean (s.d.) age of 40 (12) y.Methods: TBW measured by deuterium oxide dilution; resistance (R) of arms, trunk and legs measured at frequencies of 5, 50, 250 and 500 kHz with an eight-polar tactile-electrode impedance-meter (InBody 3.0, Biospace, Seoul, Korea).Results: An algorithm for the prediction of TBW from the whole-body resistance index at 500 kHz (height 2/R500 where R is the sum of the segmental resistances of arms, trunk and legs) was developed in a randomly chosen subsample of 35 subjects. This algorithm had an adjusted coefficient of determination (r2adj) of 0.81 (P<0.0001) and a root mean square error (RMSE) of 3.6 l (9%). Cross-validation of the predictive algorithm in the remaining 15 subjects gave an r2adj of 0.87 (P<0.0001) and an RMSE of 3.0 l (8%). The precision of eight-polar BIA, determined by measuring R three times a day for five consecutive days in a fasting subject, was ≤2.8% for all segments and frequencies.Conclusion: Eight-polar BIA is a precise method that offers accurate estimates of TBW in healthy subjects. This promising method should undergo further studies of precision and its accuracy in assessing extracellular water and appendicular body composition should be determined.Sponsorship: Modena and Reggio Emilia University.

Sensitivity and specificity of body mass index and skinfold thicknesses in detecting excess adiposity in children aged 8-12 years.

Primary objective : The study aimed to evaluate the sensitivity (SN) and specificity (SP) of body mass index (BMI) and skinfold thicknesses in detecting excess adiposity in children. Research design : Cross-sectional. Materials and methods : 986 children (500 females and 486 males) aged 10 - 1 years (mean - SD; range: 8-12 years) were studied. All underwent anthropometric measurements and bioelectrical impedance analysis (BIA). Dual-energy X-ray absorptiometry (DXA) was performed in 52 children to develop a population-specific algorithm for the assessment of fat-free mass (FFM) from BIA. The algorithm was applied to the remaining 934 children to estimate their FFM. Fat mass (FM) was obtained by subtracting FFM from weight (Wt). Values of FM:Wt were transformed in Z -scores and converted into 19 percentile categories (from 5 to 95 in steps of 5). The same procedure was performed with BMI and the log-transformed sum of four skinfold thicknesses (triceps, biceps, subscapular and suprailiac; lt-4SF). Excess adiposity was defined as a level of FM:Wt greater than the internally derived 85th percentile. SN and SP of each internally derived percentile of BMI and lt-4SF in detecting excess adiposity were calculated. Results : In the pooled sample ( n = 934), SN and SP were 0.39 and 0.99 for the 95th percentile of BMI, 0.65 and 0.95 for the 85th percentile of BMI, and 0.75 and 0.94 for the 85th percentile of lt-4SF. Conclusions : BMI percentiles employed in the present study have a high SP but a low SN in detecting excess adiposity in 8-12-year-old children. The use of the sum of four skinfolds has the potential to increase the SN of a screening programme for excess adiposity in children of this age.

Appendicular skeletal muscle mass : prediction from multiple frequency segmental bioimpedance analysis

Objectives: Bioimpedance analysis (BIA) methods have potential to predict appendicular skeletal muscle mass (SM), although available 50 kHz prediction models include, in addition to impedance (Z), an independent age term. An age term in models is undesirable as it reflects incomplete understanding of underlying conduction physiology. This study tested the hypothesis, based on fluid distribution models related to aging, that appendicular SM bioimpedance analysis (BIA) prediction models would no longer include an independent age term, after first controlling for stature-adjusted appendicular impedance (height2/Z), at injected frequencies greater than 50 kHz.Design: Cross-sectional evaluation of adults who had segmental Z and phase angle (Φ) measured with multiple frequency BIA, and arm and leg SM with dual-energy X-ray absorptiometry (DXA). Skeletal muscle prediction models were developed with appendicular SM as dependent variable and height2/Z, gender, age and Φ as potential independent variables.Results: Examination of hypothesis in 49 subjects indicated: both arm and leg SM were highly correlated with height2/segmental Z at frequencies ranging from 1–300 kHz; gender was significant covariate in prediction models only at 1 kHz; age remained a significant covariate after controlling for height2/segmental Z at all frequencies; Φ did not add significantly to models; and SM prediction models gave maximum R2 at 50 kHz for arm but R2 continued to rise up to 300 kHz for leg.Conclusion: Although multifrequency BIA did not eliminate SM prediction model age term, our findings suggest injected frequencies up to 300 kHz may have advantages for evaluating leg SM over conventional 50 kHz method.Sponsorship: This study was in-part supported by NIH Grant RO1-NIDDK 42618 and a Scholarship awarded to Dr Pietrobelli from University of Milan, H San Raffaele, Italy.

Gestational weight gain in overweight and obese women enrolled in a healthy lifestyle and eating habits program

Abstract Objectives: To determine whether changes in lifestyle in women with BMI > 25 could decrease gestational weight gain and unfavorable pregnancy outcomes. Methods: Women with BMI > 25 were randomized at 1st trimester to no intervention or a Therapeutic Lifestyle Changes (TLC) Program including diet (overweight: 1700 kcal/day, obese: 1800 kcal/day) and mild physical activity (30 min/day, 3 times/week). At baseline and at the 36th week women filled-in a Food Frequency Questionnaire. Outcomes: gestational weight gain, gestational diabetes mellitus, gestational hypertension, preterm delivery. Data stratified by BMI categories. Results: Socio-demographic features were similar between groups (TLC: 33 cases, Controls: 28 cases). At term, gestational weight gain in obese women randomized to TLC group was lower (6.7 ± 4.3 kg) versus controls (10.1 ± 5.6 kg, p = 0.047). Gestational diabetes mellitus, gestational hypertension and preterm delivery were also significantly lower. TLC was an independent factor in preventing gestational weight gain, gestational diabetes mellitus, gestational hypertension. Significant changes in eating habits occurred in the TLC group, which increased the number of snacks, the intake of fruits–vegetables and decreased the consumption of sugar. Conclusions: A caloric restriction associated to changes in eating behavior and constant physical activity, is able to reduce gestational weight gain and related pregnancy complications in obese women.

Measured physical activity in anorexia nervosa: features and treatment outcome.

OBJECTIVE To assess the role of measured physical activity (PA) in anorexia nervosa treatment outcome, and to compare the PA of patients with anorexia nervosa with age-matched controls. METHOD PA was assessed by means of Sense Wear Armband before and after a cognitive-behavioral inpatient treatment in 53 consecutive females with anorexia nervosa, and in 53 healthy age-matched controls. RESULTS At baseline, patients with anorexia nervosa exhibited a higher duration of moderate-vigorous PA (MVPA≥3 Metabolic Equivalent Tasks (METs)) than controls (t = 2.91; p = .004). Dropouts had higher duration (sec) and expenditure (kcal·day(-1)) of MVPA than completers. At the end of treatment, completers had a higher number of daily steps, MVPA duration, and expenditure than controls. However, PA was not correlated to eating disorder psychopathology either before or after treatment. DISCUSSION PA is higher in patients with anorexia nervosa than age-matched controls both before and after treatment, and is associated with treatment dropout.

Relationship between body composition and bone mineral content in young and elderly women.

Primary objective : To study the relationship between bone mineral content (BMC), lean tissue mass (LTM) and fat mass (FM) in a large sample of young and elderly women. Research design : Cross-sectional. Methods and procedures : BMC, LTM and FM were measured by dual-energy X-ray absorptiometry in 2009 free-dwelling Caucasian women aged 63 - 7 years (mean - SD; range: 37-88 years). The majority of women were postmenopausal (96%). Results : LTM explained 13% more variance of BMC than FM ( R 2 adj = 0.39 vs 0.26, p < 0.0001) but weight (Wt) explained 5% more variance of BMC than LTM ( R 2 adj = 0.44, p < 0.0001). The prediction of BMC obtained from LTM and FM ( R 2 adj = 0.46, p < 0.0001) was only slightly better than that obtained from Wt. After the effects of age, Wt and height (Ht) on BMC were taken into account by multiple regression, the contribution of LTM and FM to BMC was just one-fifth of that of Wt ( R 2 adj for full models r 0.56, p < 0.0001). After a further correction for bone area (BA), the contribution of LTM and FM to BMC was just one-tenth of that of BA and not different from that of Wt and Ht on practical grounds ( R 2 adj for full models = 0.84, p < 0.0001). Thus, after inter-individual differences in age, Wt, Ht (and bone size) are taken into account, the relationship between body composition and BMC is substantially weakened. Conclusions : In Caucasian women, (1) LTM is a stronger predictor of BMC than FM, but (2) Wt is a better predictor of BMC than body composition for practical purposes, and (3) Wt and body composition are not able to explain more than 46% of BMC variance.

Short-term multidisciplinary non-pharmacological intervention is effective in reducing liver fat content assessed non-invasively in patients with nonalcoholic fatty liver disease (NAFLD)

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis to steatohepatitis, and cirrhosis in patients with alcohol intake less than 20 g/day, and is usually associated with insulin resistance (IR). AIM Given that no drugs are specifically approved for NAFLD, we tested the efficacy of a non-pharmacological multidisciplinary intervention based on a personalized diet, physical activity and behavior therapy. METHODS In this open non-randomized study, personalized diet, physical exercise and behaviour therapy for 3 months were prescribed in 12 consecutive patients with NAFLD. Lifestyle, including total caloric intake, physical activity and resting energy expenditure was monitored by a SenseWear Armband. Insulin Resistance (IR) was measured by HOMA and oral glucose insulin sensitivity tests (OGIS); fat liver content was estimated by two different semi-quantitative scores and by the Doppler Power Index (DPI). RESULTS Data show that the multidisciplinary intervention produced a significant reduction of total caloric intake, a 8% reduction in body weight, a modest increase in daily physical activity, a significant (P<0.001) reduction of aminotransferases and a decrease of total hepatic fat content. CONCLUSIONS A 3-month multidisciplinary intervention inducing at least 8% of weight loss, improves liver tests and decreases liver fat content.

The prediction of total body water and extracellular water from bioelectric impedance in obese children.

Objectives: To assess the reliability of bioelectric impedance analysis (BIA) for predicting total body water (TBW) and extracellular water (ECW) in obese children.Design: Comparison of five prediction models based on: (i) body weight (Wt), (ii) the impedance (Z) index (ZI=height2/Z), (iii) the association of Wt and ZI, (iv) the body surface area (SA) to impedance ratio (SA:Z) and, (v) the body volume (V) to impedance ratio (V:Z).Subjects: Thirty obese and 25 control children of 11.2±1.8 y of age.Measurements: TBW and ECW were assessed by deuterium and bromide dilution; Z was measured at frequencies of 5, 50 and 100 kHz.Results: In controls, Wt explained 11% more variance of TBW than ZI (r2=0.977, SEE=0.9 I, CV=3.8%) and the association of Wt and ZI improved the prediction of TBW only slightly (r2=0.982, SEE=0.8 I, CV=3.5%). The SA:Z and V:Z indexes explained 6 and 33% less variance of TBW respectively as compared to Wt alone. In obese subjects, ZI explained 4% more variance of TBW than Wt (r2=0.914, SEE=1.8 I, CV=6.4%) and the SA:Z ratio was the most accurate predictor of TBW (r2=0.959, SEE=1.2 I, CV=4.4%). However, the increase in the explained variance of TBW associated to the use of the SA:Z ratio was of only 1% as compared to the association of ZI and Wt. The V:Z ratio explained 9% less of variance of TBW as compared to ZI. In both control and obese subjects, the association of Wt and ZI offered the best prediction of ECW (r2=0.807, SEE=1.564 I and r2=0.826, SEE=1.035 I, respectively). However, the values of CV were much higher in controls than in obese children (17.5% vs 8.4%) owing to their lower ECW and greater variability in ECW%. ZI was the most accurate predictor of TBW on the pooled sample (n=55; r2=0.910, SEE=1.932 I, CV=7.4%). However, it was a poor predictor of ECW on the same sample owing to its high CV (n=55; r2=0.866, SEE=1.806 I, CV=17.0%).Conclusions: The body surface area to impedance ratio is the most accurate predictor of TBW in obese children but the association of ZI and Wt may be of more interest when BIA is used to estimate both TBW and ECW. The impedance index offers a good prediction of TBW but not of ECW in children with different levels of fatness.Sponsorship: Supported by grant 9304260.CT04 from CNR, Italy.

Multifrequency bioelectric impedance measurements for predicting body water compartments in duchenne muscular dystrophy

Body hydration and extra- to intra-cellular water ratio (ECW: ICW) have been studied in 12 duchenne muscular dystrophy (DMD) patients and 15 healthy controls. Subjects underwent total body water (TBW) and extracellular water (ECW) assessment by deuterium and bromide dilution, respectively. Multifrequency bioelectric impedance analysis (MFBIA) was performed on all subjects with the aim to establish its accuracy in predicting TBW and ECW in DMD. Body hydration was lower (51.8 +/- 2.8 vs 58.5 +/- 5.9%, P < 0.01) and the ECW: ICW ratio higher (1.15 +/- 0.25 vs 0.70 +/- 0.23, P < 0.001) in DMD than in control subjects. Hence, control-generated formulae for predicting TBW and ECW from MFBIA gave inaccurate results in DMD subjects. Population-specific formulae were developed to obtain an accurate prediction of body water compartments in DMD patients.