Body Composition in Youths Aged 10‒17 Years by Deuterium Oxide Dilution, Air Displacement Plethysmography, and DXA: Validation of the Medical Body Composition Analyzer Bioimpedance Device by a 4-Compartment Model

BACKGROUND

The medical body composition analyzer (mBCA) incorporates advances in multifrequency technology and has been validated using a 4-compartment (4C) model in adults but not in youths aged <18 y.

OBJECTIVES

This study aimed to formulate a 4C model based on 3 reference methods and develop and validate a body composition prediction equation for the mBCA in youths aged 10‒17 y.

METHODS

The body density of 60 female and male youths was measured by air displacement plethysmography, total body water by deuterium oxide dilution, and BMC by DXA. Data from the equation group (n = 30) were used to formulate a 4C model. The all-possible-regressions method was used to select variables. The model was validated in a second cohort (n = 30) in a random split design. The accuracy, precision, and potential bias were evaluated by the Bland and Altman procedure.

RESULTS

Mean age, weight (W), height (H), waist circumference, and z-score of BMI were 13.6 ± 2.3 y, 54.5 ± 15.5 kg, 156 ± 11.9 cm, 75.5 ± 10.9 cm, and 0.70 ± 1.32 z, respectively. The prediction equation was as follows: FFM in kg (FFM_kg) = ([0.2081] ∗ [W] + [0.8814] ∗ [H²_cm/R_Ω] + [0.2055 ∗ Xc_Ω])-15.343; R² = 0.96; standardized root-mean-square error (SRMSE) = 2.18 kg. FFM did not differ between the 4C method (38.9 ± 12.0 kg) and the mBCA (38.4 ± 11.4 kg) (P > 0.05). The relationship between these 2 variables did not deviate from the identity line, was not significantly different from 0, and the slope was not significantly different from 1.0. In the precision prediction model of mBCA, the R² value was 0.98 and SRMSE was 2.1. No significant bias was found when regressing differences between methods and their means (P = 0.08).

CONCLUSIONS

The equation for the mBCA was accurate, precise, had no significant bias, had substantial strength of agreement and could be used in this age group when subjects were preferentially within the constraints of a specified body size.

Real-world efficacy of switching to bictegravir/ emtricitabine/tenofovir alafenamide in pretreated patients with triple therapy containing rilpivirine

Objetivo

Analizar la eficacia y tolerabilidad de la estrategia de cambio desde regímenes basados en rilpivirina (RPV) a bictegravir/emtricitabina/tenofovir alafenamida (B/F/TAF) en la vida real.

Métodos

Estudio unicéntrico, observacional y retrospectivo. Se seleccionaron pacientes que cambiaron de un régimen con RPV a B/F/TAF antes de febrero del 2020 analizándose los resultados después de 24 y 48 semanas. Se determinó el porcentaje que permanecía con carga viral indetectable, así como los cambios en linfocitos CD4+, parámetros metabólicos y función renal.

Resultados

Se incluyeron en el estudio 42 pacientes. 32 de los 35 (91,4%) que completaron las 48 semanas de seguimiento tenían carga viral indetectable. El recuento de linfocitos CD4+ permaneció estable a las 24 y a las 48 semanas. El tipo de análogos recibidos previamente no influyó en la respuesta

Conclusión

El cambio desde una triple terapia con RPV a B/F/TAF es una estrategia segura y eficaz en la vida real.

Systematic training in master swimmer athletes increases serum insulin growth factor-1 and decreases myostatin and irisin levels

During ageing, anabolic status is essential to prevent the decrease in quantity and quality of skeletal muscle mass (SMM). Exercise modulates endocrine markers of muscle status. We studied the differences of endocrine markers for muscle status in 62 non-sarcopenic Mexican swimmer adults aged 30-70 y/o, allocated into two groups: the systematic training (ST) group including master athletes with a physical activity level (PAL) >1.6, and the non-systematic training group (NST) composed by subjects with a PAL <1.5. Body composition, diet, biochemical and endocrine markers were analyzed. The ST group showed lower myostatin (MSTN) and irisin (IRI) levels, two strong regulators of SMM. The insulin growth factor-1 (IGF-1) was higher in the ST. This is consistent with most of the evidence in young athletes and resistance training programs, where IGF-1 and IRI seem to play a crucial role in maintaining anabolic status in master athletes.

Pinto Bean Amino Acid Digestibility and Score in a Mexican Dish with Corn Tortilla and Guacamole, Evaluated in Adults Using a Dual-Tracer Isotopic Method

BACKGROUND

Ultra-processed foodstuffs have been replacing traditional beans with tortillas in the Mexican diet in the last decades. Therefore, scientific support is needed to promote a return to good-quality traditional dishes.

OBJECTIVES

This study aims to evaluate the amino acid digestibility and score of pinto beans (Phaseolus vulgaris) consumed with corn tortillas and guacamole in adults using the dual-tracer method.

METHODS

The pinto beans were intrinsically labeled using 250 mL of 2H2O (99.8%) per 19 L pot with 3 plants. A paste of cooked beans on toasted corn tortillas and guacamole topping were administered to 3 male and 3 female adults (21-25 years old; BMI, 19-23.5 kg/m2). The protocol was plateau feeding given along with U-[13C]-spirulina protein to evaluate indispensable amino acid (IAA) digestibility using the dual-tracer method. Blood samples were taken in the plateau state. The digestibility of each IAA of the bean protein was calculated by the ratio of its enrichment in the beans to the spirulina in the meal and its appearance in plasma collected in the plateau state, as a percentage corrected by spirulina digestibility. Additionally, the digestible IAA score (DIAAS) was calculated.

RESULTS

The 2H enrichment of IAA in the pinto beans was 471 parts per million excess. The isotopic enrichment of 2H and 13C in IAA at 5-8 hours presented plateau states with mean CVs of 12.2% and 13.3%, respectively. The mean digestibility of IAA from pinto beans was 77% ± 1.6%, with the lowest value for threonine. The DIAAS calculated with respect to the pattern requirement for children older than 3 years, adolescents, and adults was 83%, with methionine and cysteine being the limiting amino acids.

CONCLUSIONS

A Mexican dish of pinto beans, tortillas, and guacamole is a good source of protein as evaluated in adults and could be promoted as a nutritious snack. The assay is registered with the Ethical Committee of the Centro de Investigación en Alimentación y Desarrollo, A.C. as CE/015/2019.

Metabolic syndrome screening using visceral adipose tissue (VAT) from opportunistic MRI locations in a multi-ethnic population

OBJECTIVE

To determine if visceral adipose tissue (VAT) area measured through MRI can be used opportunistically to assess the presence of cardiometabolic risk factors and compare its performance to simpler adiposity measures.

METHODS

A cross-sectional analysis was carried out on a subset of 1683 participants (856 women) from the Adiposity Phenotype Study (mean age=69.2y; range 59.9-77.4). The association of total VAT area (sum of four cross sections, L1-L2, L2-L3, L3-L4, L4-L5) and each location, as well as BMI and body fat % (per SD) with the metabolic syndrome (MetSx) or its components was evaluated through logistic regression analysis.

RESULTS

Total VAT can be accurately predicted using all sites evaluated (R² range=0.82-0.96). In men, VAT did not show a superior association to MetSx compared to BMI in men. However, in women, VAT was consistently superior to BMI and body fat % in its association to MetSx, independent of ethnicity [odds ratio for BMI, body fat %and total VAT area=2.25 (95% CI: 1.93-2.62); 1.66 (95% CI: 1.36-2.03); 6.20 (95% CI: 4.69-8.21) respectively in all women]. Ethnic-specific odds ratios to MetSx in women ranged from 5.38 to 8.63 for total VAT area and 2.12-4.08 for BMI.

CONCLUSION

Total VAT area can be accurately predicted from individual VAT regions in men and women and offers superior association to BMI for MetSx in women but not in men for five ethnicities. Therefore, opportunistic screening for elevated VAT area in women may be warranted across multiple ethnic groups.

The "Super-Child" Approach Is Applied To Estimate Retinol Kinetics and Vitamin A Total Body Stores in Mexican Preschoolers

BACKGROUND

Retinol isotope dilution (RID) and model-based compartmental analysis are recognized techniques for assessing vitamin A (VA) status. Recent studies have shown that RID predictions of VA total body stores (TBS) can be improved by using modeling and that VA kinetics and TBS in children can be effectively studied by applying population modeling ("super-child" approach) to a composite data set.

OBJECTIVES

The objectives were to model whole-body retinol kinetics and predict VA TBS in a group of Mexican preschoolers using the super-child approach and to use model predictions of RID coefficients to estimate TBS by RID in individuals.

METHODS

Twenty-four healthy Mexican children (aged 3-6 y) received an oral dose (2.96 μmol) of [13C10]retinyl acetate in corn oil. Blood samples were collected from 8 h to 21 d after dosing, with each child sampled at 4 d and at 1 other time. Composite data for plasma labeled retinol compared with time were analyzed using a 6-component model to obtain group retinol kinetic parameters and pool sizes. Model-predicted TBS was compared with mean RID predictions at 4 d; RID estimates at 4 d were compared with those calculated at 7-21 d.

RESULTS

Model-predicted TBS was 1097 μmol, equivalent to ∼2.4 y-worth of VA; using model-derived coefficients, group mean RID-predicted TBS was 1096 μmol (IQR: 836-1492 μmol). TBS at 4 d compared with a later time was similar (P = 0.33). The model predicted that retinol spent 1.5 h in plasma during each transit and recycled to plasma 13 times before utilization.

CONCLUSIONS

The super-child modeling approach provides information on whole-body VA kinetics and can be used with RID to estimate TBS at any time between 4 and 21 d postdose. The high TBS predicted for these children suggests positive VA balance, likely due to large-dose VA supplements, and warrants further investigation.

Association of cagA+ Helicobacter pylori strains with high urease activity and dyspepsia in Mexican adults

INTRODUCTION AND AIMS

Helicobacter pylori (H. pylori) is associated with a higher risk of peptic ulcer and gastric cancer. The sole presence of the bacterium is not a determinant of clinical outcome, but rather the interaction of strain type and host factors determines the risk of disease. Our aim was to study the association between bacterial load, strain type, and gastric symptoms in H. pylori-positive subjects.

MATERIALS AND METHODS

In a community survey, a diagnostic ¹³C-urea breath test for H. pylori was performed on 302 volunteers that were not taking antibiotics, antacids, or proton pump inhibitors one month prior to the test. The breath test produced 25 H. pylori-positive subjects, between 25-74 years of age, who then took a gastric symptoms survey and were tested for the presence of the cagA genotype in gastric juice, using the Entero-test®. Bacterial load was determined as a measure of urease activity, utilizing the delta over baseline value, obtained in the ¹³C-urea breath test.

RESULTS

A total of 48% of the H. pylori-positive subjects were cagA+. A positive association was found between cagA status and high gastric urease activity (P<.0001) and the latter was significantly associated with the presence of symptoms (P<.0001).

CONCLUSION

Gastric urease activity was strongly associated with dyspeptic symptoms and cagA+ H. pylori. Elevated ¹³C-delta over baseline values could be used as indicators of a higher risk for gastric disease.

[Helicobacter pylori infection in the HIV + population: a comorbidity to think about]

Introducción

. Las alteraciones gastrointestinales, son frecuentes en VIH+. Helicobacter pylori puede ser una causa infradiagnosticada.

Material y métodos

Se realizó una búsqueda retrospectiva de pacientes VIH+ con infección por H. pylori entre enero de 1998 hasta diciembre de 2017.

Resultados

Se incluyeron 132 pacientes. La dispepsia fue la sintomatología más frecuente. Un 88,5% tuvo gastritis crónica atrófica. Se consiguió la erradicación en 102 (77,3%). La curación fue más frecuente con pauta cuádruple (p=0,004) y en los más jóvenes (p=0,041).

Conclusión

La infección por H. pylori podría ser responsable de manifestaciones digestivas inespecíficas en los pacientes VIH+.

Effectiveness of the Diabetes Prevention Program for Obesity Treatment in Real World Clinical Practice in a Middle-Income Country in Latin America

The Diabetes Prevention Program (DPP) is effective for the prevention of type 2 diabetes by weight loss with diet and physical activity. However, there is little evidence as to whether this program could be translated into real-world clinical practice in Latin American countries. The objective of this work was to evaluate the effectiveness of the DPP for the management of overweightness and obesity at 6 and 12 months in clinical practice in Mexico. This was a non-controlled intervention study implemented in five public clinics in northern Mexico. Two hundred and thirty-seven adults aged 45.7 ± 9.9 years with a Body Mass Index (BMI) of 34.4 ± 5.4 kg/m² received group sessions with an adaptation of the DPP, in addition to nutrition counseling. One hundred and thirty-three (56%) participants concluded the 6 month phase. They showed a significant weight loss, ranging from 2.76 ± 4.76 to 7.92 ± 6.85 kg (p ≤ 0.01) in the clinics. The intention-to-treat analysis showed a more conservative weight loss. Participant retention at the end of 12 months was low (40%). The implementation of the DPP in different public clinics in Mexico was effective in the management of obesity in the short term, but better strategies are required to improve participant retention in the long term.

Serum Retinol and Anemia in Women of Reproductive Age from Saint-Marc, Haiti (P02-008-19)

Objectives

The objective was to assess serum retinol concentration in women of reproductive age from Haiti by HPLC and a portable photometer, as well as the presence of anemia and hemoglobin (Hb) concentration.

Methods

Cross-sectional comparative study design. Women of reproductive age from the program to improve food security in Haiti (AKOSAA) were eligible to participate. Weight and height were measured and Body Mass Index (BMI) was calculated. A sample of venous blood (5 mL) was collected to assess serum retinol (SR) using HPLC and a portable photometer. Hemoglobin concentration was determined using HemoCue and C-reactive protein (Spinreact E-17176, St Esteve de Bas), was used as a marker of inflammation.

Results

Age range among participants (n = 163) was 15–50 years old. Low weight was identified in15% (n = 24) of enrolled women according to BMI. Vitamin A deficiency (VAD) was identified in 55% (n = 90) of the study population according to serum retinol assessed by HPLC (reference method) versus 26.4% identified using the portable photometer (weighted Kappa = 0.10), which is considered extremely poor. Severe VAD was not found but mild and severe VAD was identified in 38.7% and 16% of women, respectively. When the difference and average of measurements of both methods were compared, bias was 0.20 (IC 95%: 0.14, 0.27). Lin's concordance coefficient (ρc), an analysis of accuracy and precision that assesses how every pair of observations falls over the line of identity (45°), was extremely poor, because it was found below 0.90 (ρc = 0.19). On the other hand, 45% (n = 73) of participants had anemia (Hb < 12 g/dL). No inflammation was observed, since C-reactive protein was below 6 mg/L.

Conclusions

In Haiti VAD as well as anemia were found to be a public health problem. As long as the socioeconomical situation does not substantially improve in this región, supplementation policies and food fortification must be implemented to be able to fight hidden hunger.

Funding Sources

International Atomic Energy Agency (IAEA) CRP contract No. 18,223. Sight and Life donated the iCheckFluoro® equipment and reagents.

Isotopic Tools for Strengthening Health and Nutritional Monitoring and their Current Applications in Developing Regions of the World

Nuclear and isotope methods in one form or another are regarded as essential tools for carrying out nutrition research besides enhancing sensitivity of nutrition monitoring techniques. They have been used extensively in industrialized countries to analyze human energy requirements, body composition including bone mineral density, to determine food composition, and to study metabolism of important nutrients such as protein, fat, vitamins, and minerals. The information acquired has led to many improvements in nutrition and health. Importantly, the developmental needs of countries in economic transition are being increasingly identified and resolved through field applications of isotopic tools, thus strengthening health and nutrition monitoring. Currently, several strategic applications of isotopic techniques are being introduced in developing countries where they can benefit millions through monitoring improvement in nutritional status, and serve as specific indicators of broader social and economic advances. These examples are highlighted in this report.

Body Composition in Mexican Adults by Air Displacement Pletismography (ADP) with the Bod-Pod and Deuterium Oxide Dilution Using Infrared Spectroscopy (IRS-DOD)

Thirty four subjects (13 men and 21 women), 24 to 70 years old from northern Mexico, were measured for body density by air displacement plethysmography (ADP) with the BOD-POD, and for total body water by deuterium oxide dilution and infrared spectroscopy (IRS-DOD). Subjects were given a 30 g dose of deuterium oxide. Saliva samples were filtered, sublimated, and deuterium was measured using a Miran 1 FF, IRS. Linear regression of the fat mass (FM) derived from both methods showed that the intercept (0.071) was not different from zero (p = .96) and the slope was 0.96 (p < .0001) demonstrating the techniques to be equivalent. Further, mean FM was 26.7 ± 12.4 and 25.6 ± 12.4 kg, for IRS-DOD and ADP techniques, respectively (p = .08). Precision analysis by the model R2 showed that 92.3% of the variability was explained (SEM = 3.4 kg). Bland-Altman analysis showed no significant bias (r = 0.017; p = .93). Mean difference between methods was −1.08 (CI: −2.3 to + 0.13) kg FM.

Measurement of Deuterium Oxide by Infrared Spectroscopy and Isotope Ratio Mass Spectrometry for Quantifying Daily Milk Intake in Breastfed Infants and Maternal Body Fat

Measurements of deuterium oxide concentrations (DOC) in saliva by infrared spectroscopy (IRS) and isotope ratio mass spectrometry (IRMS) were compared for the calculation of infants’ milk intake and maternal body fat. Deuterium oxide (30g) was given to the mother. DOC by IRS and IRMS were 340 ± 209 and 345 ± 202 ppm. The mean difference between both methods (4.62 ± 76.3) was not different from zero (p = .57). Bland and Altman analysis showed no significant overall bias (r = 0.10; p = .33), but dispersion within the limits of agreement. The mean milk intake in the infants’ by IRS and IRMS were 624 ± 296 g/day and 634 ± 327 g/day (p = .642) and the mothers’ mean body fat were 31.3 ± 12% and 31.5 ± 13% (p = .755). The results appear to be the same for milk intake and body fat by the two methods and no evidence of bias was found.

Analysis of type 2 diabetes and obesity genetic variants in Mexican Pima Indians: Marked allelic differentiation among Amerindians at HLA

Prevalence of diabetes and obesity in Mexican Pima Indians is low, while prevalence in US Pima Indians is high. Although lifestyle likely accounts for much of the difference, the role of genetic factors is not well explored. To examine this, we genotyped 359 single nucleotide polymorphisms, including established type 2 diabetes and obesity variants from genome-wide association studies (GWAS) and 96 random markers, in 342 Mexican Pimas. A multimarker risk score of obesity variants was associated with body mass index (BMI; β = 0.81 kg/m² per SD, P = 0.0066). The mean value of the score was lower in Mexican Pimas than in US Pimas (P = 4.3 × 10^-11 ), and differences in allele frequencies at established loci could account for approximately 7% of the population difference in BMI; however, the difference in risk scores was consistent with evolutionary neutrality given genetic distance. To identify loci potentially under recent natural selection, allele frequencies at 283 variants were compared between US and Mexican Pimas, accounting for genetic distance. The largest differences were seen at HLA markers (e.g., rs9271720, difference = 0.75, P = 8.7 × 10^-9 ); genetic distances at HLA were greater than at random markers (P = 1.6 × 10^-46 ). Analyses of GWAS data in 937 US Pimas also showed sharing of alleles identical by descent at HLA that exceeds its genomic expectation (P = 7.0 × 10^-10 ). These results suggest that, in addition to the widely recognized balancing selection at HLA, recent directional selection may also occur, resulting in marked allelic differentiation between closely related populations.

Translational study of obesity management using the Diabetes Prevention Program "Group Lifestyle Balance" in primary care clinics and public hospitals from Mexico: study protocol

Introducción: La obesidad es el principal factor de riesgo para el desarrollo de enfermedades crónicas en México. Varios ensayos clínicos controlados han mostrado que los programas intensivos de cambio de estilo de vida son eficaces para el manejo de obesidad. Estos programas incluyen sesiones frecuentes (14 o más los primeros 6 meses), centradas en hacer mejoras en la dieta y actividad física utilizando un protocolo de cambio de comportamiento. Sin embargo, la mayoría de clínicas de primer nivel y los hospitales públicos aplican tratamientos tradicionales para el manejo de obesidad que tienen resultados limitados. El propósito del estudio es evaluar la efectividad del Programa de Prevención de Diabetes “Grupo de Equilibrio de Estilo de Vida” sobre la pérdida de peso en adultos con sobrepeso y obesidad del inicio a 6 meses y del inicio a 12 meses del seguimiento en clínicas de primer nivel y hospitales públicos de Sonora, México.Material y Métodos: Este es un estudio clínico multicéntrico traslacional, no controlado con diseño pre y post-prueba a 6 y 12 meses. Los proveedores de salud de dos clínicas de primer nivel, dos hospitales públicos y una clínica universitaria serán entrenados con el protocolo del Programa de Prevención de Diabetes, para implementarlo en sus pacientes adultos con sobrepeso y obesidad. Se medirá el peso corporal, índice de masa corporal, circunferencia de cintura, presión sistólica y diastólica, así como escalas de depresión, calidad de vida y estrés, al inicio, 6 y 12 meses. Los parámetros bioquímicos se medirán al inicio y a los 12 meses. La variable de desenlace primaria será el cambio de peso a 6 y 12 meses.Discusión: Este estudio proveerá evidencia científica de la efectividad del protocolo del Programa de Prevención de Diabetes como un modelo para el manejo de obesidad en adultos mexicanos en condiciones de la práctica clínica del mundo real.

Effect of the Holiday Season on Weight Gain: A Narrative Review

Several studies suggest that the holiday season, starting from the last week of November to the first or second week of January, could be critical to gaining weight. This study aims to review the literature to determine the effects of the holidays on body weight. In studies of adults, a significant weight gain was consistently observed during this period (0.4 to 0.9 kg, p < 0.05). The only study in college students found an effect on body fat but not on weight (0.1 kg, p = 0.71). The only study found in children did not show an effect on BMI percentile (-0.4%, p > 0.05) during this period. Among individuals with obesity who attempt to lose weight, an increase in weight was observed (0.3 to 0.9 kg, significant in some but not in all studies), as well as increase in weight in motivated self-monitoring people (0.4 to 0.6%, p < 0.001). Programs focused on self-monitoring during the holidays (phone calls and daily mailing) appeared to prevent weight gain, but information is limited. The holiday season seems to increase body weight in adults, even in participants seeking to lose weight and in motivated self-monitoring people, whereas in children, adolescents, and college students, very few studies were found to make accurate conclusions.

'Dose-to-Mother' Deuterium Oxide Dilution Technique: An Accurate Strategy to Measure Vitamin A Intake in Breastfed Infants

In Mexico, infants (0–2 years old) show the highest prevalence of vitamin A deficiency (VAD), measured by serum retinol concentrations. Thus, we consider that low vitamin A (VA) intake through breast milk (BM) combined with poor weaning practices are the main factors that contribute to VAD in this group. We combined the assessment of VA status in lactating women using BM retinol and a stable isotope ‘dose-to-mother’ technique to measure BM production in women from urban and agricultural areas. Infants’ mean BM intake was 758 ± 185 mL, and no difference was observed between both areas (p = 0.067). Mean BM retinol concentration was 1.09 μmol/L, which was significantly lower for the agricultural area (p = 0.028). Based on BM retinol concentration, 57% of women were VAD; although this prevalence fell to 16% when based on fat content. Regardless of the VA biomarker used here, infants from the urban and agricultural areas cover only 66% and 49% of their dietary adequate intake from BM, respectively (p = 0.054). Our data indicate that VAD is still a public health concern in Mexico. Adopting both methods to assess VA transfer from the mother to the breastfed child offers an innovative approach towards the nutritional assessment of vulnerable groups.

Antineoplastic treatment effect on bone mineral density in Mexican breast cancer patients

BACKGROUND

Breast cancer is the most deadly malignancy in Mexican women. Although treatment has improved, it may significantly affect bone mineral status in those who receive it. The aim of this study was to assess the impact of cancer treatment on bone mineral density (BMD) and bone mineral content (BMC), in patients with breast cancer and explore the interaction of menopausal status and clinical stage with cancer treatment on such changes.

METHODS

A quasi-experimental design was applied with measurements before and after a chemotherapy treatment in 40 patients with primary diagnosis of invasive breast cancer. BMD and body composition measurements were taken by dual X-ray absorptiometry (DXA) and changes in these variables due to therapy were analyzed using mixed regression for repeated measurements.

RESULTS

Significant loss was found in femoral neck and L2-L4 BMD (p < 0.001). Patients diagnosed with osteopenia or osteoporosis received calcium + vitamin D supplementation (600 mg/200 IU day). It showed a protective effect in the decrease of femoral neck BMD and total BMC. BMD loss in both femoral neck and L2-L4 BMD was higher in premenopausal women: 0.023 g/cm² in femoral neck and 0.063 g/cm² in L2-L4 (p < 0.001), while in postmenopausal women BMD loss was 0.015 g/cm² in femoral neck and 0.035 g/cm² in L2-L4 (p = 0.021 and p = 0.001 respectively). Change in lumbar spine BMD was prominent in premenopausal women with advanced clinical stage (IIB, IIIA, IIIB): 0.066 g/cm² (p = 0.003).

CONCLUSION

The antineoplastic breast cancer treatment with chemotherapy had a negative impact on BMD, in premenopausal women overall, although a differential effect was found according to clinical stage and calcium supplementation status.

Environmentally Driven Increases in Type 2 Diabetes and Obesity in Pima Indians and Non-Pimas in Mexico Over a 15-Year Period: The Maycoba Project

OBJECTIVE

The global epidemics of type 2 diabetes and obesity have been attributed to the interaction between lifestyle changes and genetic predisposition to these diseases. We compared the prevalences of type 2 diabetes and obesity in Mexican Pima Indians, presumed to have a high genetic predisposition to these diseases, to those in their non-Pima neighbors, both of whom over a 15-year period experienced a transition from a traditional to a more modern lifestyle.

RESEARCH DESIGN AND METHODS

Prevalence of diabetes, impaired fasting glucose, impaired glucose tolerance, and obesity in Mexican Pimas (n = 359) and non-Pima Mexicans (n = 251) were determined in 2010 using methods identical to those used in 1995.

RESULTS

During this 15-year period, age-adjusted diabetes prevalence was unchanged in Pima men (5.8% in 1995 vs. 6.1% in 2010) yet increased in non-Pima men from 0.0 to 8.6% (P < 0.05). Diabetes prevalence tended to increase in both Pima women (9.4 vs. 13.4%) and non-Pima women (4.8 vs. 9.5%). Age-adjusted prevalence of obesity increased significantly in all groups (6.6 vs. 15.7% in Pima men; 8.5 vs. 20.5% in non-Pima men; 18.9. vs 36.3% in Pima women; 29.5 vs. 42.9% in non-Pima women).

CONCLUSIONS

Type 2 diabetes prevalence increased between 1995 and 2010 in non-Pima men, and to a lesser degree in women of both groups, but it did not increase in Pima men. Prevalence of obesity increased among Pimas and non-Pimas of both sexes. These changes occurred concomitantly with an environmental transition from a traditional to a more modernized lifestyle.

Study design of the Maycoba Project: obesity and diabetes in Mexican Pimas

OBJECTIVE

To focus on the rationale and methods of the Maycoba Project.

METHODS

Study population included Mexican Pima Indians (MPI) and Blancos aged ≥20-years, living in the village of Maycoba and surrounding area. Surveys in 1995 and 2010 included a medical history, biochemical and anthropomet- ric measurements. Additionally, socio- economic, physical activity, and dietary interviews were conducted. The 2010 study incorporated investigations on type 2 diabetes (T2D) and obesity-associated genetic alleles and human-envi- ronment changes.

RESULTS

The study results are limited to demographic data and description of the eligible and ex- amined sample.

CONCLUSIONS

This study may yield important information on T2D and obesity etiology in a traditional population exposed to environmental changes.

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

Background

Although body fat percent (BF%) may be used for screening metabolic risk factors, its accuracy compared to BMI and waist circumference is unknown in a Mexican population. We compared the classification accuracy of BF%, BMI and WC for the detection of metabolic risk factors in a sample of Mexican adults; optimized cutoffs as well as sensitivity and specificity at commonly used BF% and BMI international cutoffs were estimated. We also estimated conditional BF% means at BMI international cutoffs.

Methods

We performed a cross-sectional analysis of data on body composition, anthropometry and metabolic risk factors(high glucose, high triglycerides, low HDL cholesterol and hypertension) from 5,100 Mexican men and women. The association between BMI, WC and BF%was evaluated with linear regression models. The BF%, BMI and WC optimal cutoffs for the detection of metabolic risk factors were selected at the point where sensitivity was closest to specificity. Areas under the ROC Curve (AUC) were compared among classifiers using a non-parametric method.

Results

After adjustment for WC, a 1% increase in BMI was associated with a BF% rise of 0.05 percentage points (p.p.) in men (P < 0.05) and 0.25 p.p. in women (P < 0.001). At BMI = 25.0 predicted BF% was 27.6 ± 0.16 (mean ± SE) in men and 41.2 ± 0.07 in women. Estimated BF% cutoffs for detection of metabolic risk factors were close to 30.0 in men and close to 44.0 in women. In men WC had higher AUC than BF% for the classification of all conditions whereas BMI had higher AUC than BF% for the classification of high triglycerides and hypertension. In womenBMI and WC had higher AUC than BF% for the classification of all metabolic risk factors.

Conclusions

BMI and WC were more accurate than BF% for classifying the studied metabolic disorders. International BF% cutoffs had very low specificity and thus produced a high rate of false positives in both sexes.

Vitamin A-fortified milk increases total body vitamin A stores in Mexican preschoolers

Vitamin A (VA) deficiency (VAD) continues to be a major nutritional problem in developing countries, including Central America. In Mexico, milk is a well-accepted vehicle for the administration of micronutrients, including VA, to preschoolers. Thus, we conducted a randomized, controlled, clinical trial to investigate the efficacy of daily consumption of 250 mL of VA-fortified milk (which provided 196 retinol equivalents/d) for 3 mo on VA stores in mildly to moderately VAD (serum retinol concentration 0.35-0.7 μmol/L) preschoolers who were not enrolled in a food assistance program. Twenty-seven mildly to moderately VAD children were randomly assigned based on screening measurements to either the intervention (n = 14) or control group (n = 13) (children in the control group did not receive placebo). All children in the control group and 79% (n = 11) of the children in the intervention group completed the study. The total body VA (TBVA) pool size was estimated using the deuterated retinol dilution technique before and after the intervention. After 3 mo, median changes in the serum retinol concentration for the intervention and control groups were 0.13 and -0.21 μmol/L, respectively (P = 0.009). Median changes in the TBVA stores were 0.06 and 0.01 mmol, respectively (P = 0.006) and estimated median changes in the liver VA concentration were 0.09 and 0.01 μmol/g, respectively (P = 0.002). The VA-fortified milk was well accepted among preschoolers and significantly increased TBVA stores, liver VA stores, and serum retinol concentration, indicating that it may be an effective means to ameliorate VAD in young Mexican children.

[Improvement of insulin sensitivity after an intensive lifestyle program for youth's weight management in the primary care]

The aim of this study was to evaluate an intensive lifestyle intervention for weight management among youth in a primary care setting on insulin sensibility, compared to a control group. The study included 42 youths 9-17 years old (n=23 intensive lifestyle intervention, n=19 control group) who completed a randomized trial for weight management in a primary care setting which included an oral glucose tolerance test. The intensive lifestyle intervention included monthly consultations with the primary care physician, nutrition counseling with a registered dietitian (weekly first 3 months and then monthly) and 12 group sessions in a behavioral change protocol. The control group attended monthly consultations with the primary care physician. Insulin sensitivity was estimated by the Insulin Sensitivity Index ISI(0,120) at baseline and 6 months posttreatment. At 6 months, the mean +/- DE, increase in insulin sensitivity was greater in the intensive lifestyle intervention than the control group (+46.8 +/- 56 vs. +5.6 +/- 47, between-group difference 41.2 [CI 95%, 8.5, 73.9], p = 0.01): Sixty five percent of youths on the intensive lifestyle intervention increased insulin sensitivity over 9 units vs. 32% in the control group (p=0.03). This study shows preliminary evidence that an intensive lifestyle intervention program can be an alternative model to improve insulin sensitivity among youths in the primary care setting.

Estimation of Insulin Resistance in Mexican Adults by the [(13)C]Glucose Breath Test Corrected for Endogenous Total CO(2) Production

Objective. To evaluate the efficacy of the [(13)C]glucose breath test for measuring insulin resistance in Mexican adults with different glycemic states. Research Design and Methods. Fifty-eight adults underwent a [(13)C]glucose breath test with simultaneous measurement of total CO(2) production by indirect calorimetry, at baseline and 90 minutes after the ingestion of 15 g of dextrose and 25 mg of [(13)C]glucose. HOMA was used as a marker of insulin resistance. Results. We found an inverse correlation between HOMA and the breath test δ(13)CO(2) (‰), r = -0.41 (P = 0.001). After adjusting for total CO(2) production, correlations between HOMA and fasting glucose were less strong but remained significant. An ROC curve was constructed using δ(13)CO(2) (‰) and HOMA values; the cut-off point was 9.99‰ δ(13)CO(2), corresponding to a sensitivity of 80.0 (95% CI: 51.9, 95.7) and a specificity of 67.4 (95% CI: 51.5, 80.9). Conclusions. The [(13)C]glucose breath test is a simple noninvasive procedure but was not sufficiently robust for an accurate diagnosis of insulin resistance. Our findings suggest that the test might be helpful in identifying individuals who are not IR, which in turn may contribute to improved diabetes prevention.

[Coinfection with HIV and HCV: abacavir and ribavirine, why not?]

A 48-year old male coinfected by human immunodeficiency virus and hepatitis C virus (HCV) genotype 3a. The patient was under clinically and virologically effective treatment with Trizivir (zidovudine, lamivudine and abacavir) when it was decided to initiate treatment for the chronic HCV infection with peginterferon and ribavirin. Should the ongoing antiretroviral treatment be adjusted?

Giardia lamblia infection and its implications for vitamin A liver stores in school children

BACKGROUND

Vitamin A deficiency (VAD) is a nutritional problem affecting the health of people in developing countries because VAD compromises innate and adaptive immunity, increasing a person's predisposition toward infectious diseases. In addition, a high prevalence of infectious diseases continues to be a problem in developing countries, including Giardia lamblia. G. lamblia may be related to VAD because of its ability to change the intestinal architecture, thereby compromising the absorption of vitamin A. The aim of this study was to evaluate the effect of giardiasis on serum retinol levels and vitamin A liver stores in school children.

METHODS

Thirty Giardia-infected school children participated in this study. Vitamin A liver stores were evaluated with the modified relative dose response (MRDR) technique, and antiparasitic treatment was administered. In addition, anthropometric and dietary data were collected.

RESULTS

According to anthropometric indicators (age-appropriate Z scores for weight, height and body mass index) and daily vitamin A intake, the children had a normal nutritional status. Although the mean serum retinol levels did not change significantly after treatment for Giardia (p > 0.05), the MRDR values showed significant improvement (p < 0.002).

CONCLUSION

Giardiasis not only compromises the vitamin A status through intestinal malabsorption, it also causes profound mobilization of liver retinol stores.

Differences in insulin resistance in Mexican and U.S. Pima Indians with normal glucose tolerance

CONTEXT

Insulin resistance is a major risk factor for the development of type 2 diabetes in Pima Indians, a population with the highest prevalence of type 2 diabetes mellitus in the world. Their Mexican counterpart, living a traditional lifestyle in the mountains of Sonora, have at least 5 times less diabetes than the U.S. Pima Indians.

OBJECTIVE

We evaluated whether Mexican Pima Indians had lower insulin resistance than U.S. Pima Indians.

DESIGN AND PATIENTS

We compared fasting insulin and homeostasis model assessment for insulin resistance (HOMA-IR) in 194 Mexican Pima Indians (100 females, 94 males) and 449 U.S. Pima Indians (246 females, 203 males) with normal glucose tolerance from a cross-sectional study. Adjusted differences of log-transformed outcomes (fasting insulin and HOMA-IR) between groups were evaluated using multiple linear regression models and paired t test in a matched subset.

RESULTS

Unadjusted fasting insulin and HOMA-IR were much lower in the Mexican Pima Indians than in their U.S. counterparts. After adjusting by obesity, age, and sex, mean (95% confidence interval) for fasting insulin was 6.22 (5.34-7.24) vs. 13.56 μU/ml (12.27-14.97) and for HOMA-IR 1.40 (1.20-1.64) vs. 3.07 (2.77-3.40), respectively, for Mexican Pima and U.S. Pima Indians. Results were confirmed in subset matched for age, sex, and body fat.

CONCLUSION

Our results indicate that Mexican Pima Indians have lower insulin resistance in comparison with their genetically related U.S. counterparts, even after controlling for differences in obesity, age, and sex. This finding underscores the importance of lifestyle factors as protecting factors against insulin resistance in individuals with a high propensity to develop diabetes.

[Estimation of body fat by DXA and the four compartment model in Mexican youth]

The objective of this study was to validate the estimation of body fat (%BF) by DXA (Dual-Energy X-Ray AbsorciomDPX-MD) against the four compartment model (4C) of body composition in 32 Mexican pubertal girls and boys (aged 9-14 y; F=16). The mean of the difference between DXA and 4C model was -3.5 %BF (p=0.171). The limits of agreement (95% = 2 SD) were +5% to -12%BF. The precision of estimated limits of y the confidence intervals were -1.9% to -5.1%BF (P = 0.050). The concordance correlation coefficient was p = 0.85. The test of accuracy for coincidence of slop intercepts between DXA and the 4C model showed no coincidence (p < 0.05). The precision by R2 explained 83% of the variance (SEE, 4.1%). The individual accuracy assess by the total error was 5.6%. The group mean accuracy by two way analysis of variance of body fat did not show interaction between method (DXA-4C model) and separate analysis of gender and overweight. However, there was an effect of method (p = 0.043) in the presence of overweight (p < 0.001). In conclusion, the estimation of percent of body fat by DXA was not precise and accurate in a group of Mexican children. However, results do not limit the utility of DXA for the measurements of body composition and its relation with health outcomes, especially in follow up studies.

Prediction of fat-free mass by bioelectrical impedance analysis in older adults from developing countries: a cross-validation study using the deuterium dilution method

OBJECTIVE

Several limitations of published bioelectrical impedance analysis (BIA) equations have been reported. The aims were to develop in a multiethnic, elderly population a new prediction equation and cross-validate it along with some published BIA equations for estimating fat-free mass using deuterium oxide dilution as the reference method.

DESIGN AND SETTING

Cross-sectional study of elderly from five developing countries.

METHODS

Total body water (TBW) measured by deuterium dilution was used to determine fat-free mass (FFM) in 383 subjects. Anthropometric and BIA variables were also measured. Only 377 subjects were included for the analysis, randomly divided into development and cross-validation groups after stratified by gender. Stepwise model selection was used to generate the model and Bland Altman analysis was used to test agreement.

RESULTS

FFM = 2.95 - 3.89 (Gender) + 0.514 (Ht2/Z) + 0.090 (Waist) + 0.156 (Body weight). The model fit parameters were an R2, total F-Ratio, and the SEE of 0.88, 314.3, and 3.3, respectively. None of the published BIA equations met the criteria for agreement. The new BIA equation underestimated FFM by just 0.3 kg in the cross-validation sample. The mean of the difference between FFM by TBW and the new BIA equation were not significantly different; 95% of the differences were between the limits of agreement of -6.3 to 6.9 kg of FFM. There was no significant association between the mean of the differences and their averages (r= 0.008 and p= 0.2).

CONCLUSIONS

This new BIA equation offers a valid option compared with some of the current published BIA equations to estimate FFM in elderly subjects from five developing countries.

Could giardiasis be a risk factor for low zinc status in schoolchildren from northwestern Mexico? A cross-sectional study with longitudinal follow-up

Background

Both giardiasis and zinc deficiency are serious health problems worldwide. In Mexico, the prevalence of G. intestinalis was estimated at 32% in 1994. It remains a health problem in northwestern Mexico. Recent surveys (1987, 1995, and 1999) reported zinc deficiency in the Mexican population. The association of giardiasis and malabsorption of micronutrients has been well documented, although the association with zinc remains controversial. This study investigated the association between giardiasis and zinc deficiency in schoolchildren from northwestern Mexico.

Methods

We combined a cross-sectional design with a longitudinal follow-up six months after parasite treatment. The baseline sample consisted of 114 schoolchildren (mean age 8.8 yr) from seven suburban public schools, grouped as Giardia-free (n = 65, 57%) and Giardia-infected (n = 49, 43%). Three stool analyses per child were done using Faust's method. Children with giardiasis received secnidazole. Serum zinc was determined by atomic absorption spectrophotometry. Height and weight were measured. Socioeconomic information was obtained in an oral questionnaire, and daily zinc intake was assessed using 24 hour-recalls. Pearson's correlation and ANCOVA and paired t-test analyses were used to determine the association between giardiasis and zinc status.

Results

Longitudinal analysis demonstrated a significant increase of the mean serum zinc levels in the Giardia-infected group six months after treatment (13.78 vs. 19.24 μmol/L μmol/L; p = 0.001), although no difference was found between the Giardia-free and the Giardia-infected groups (p = 0.86) in the baseline analysis. Z scores for W/A and H/A were lower in the Giardia-infected than in the Giardia-free group (p < 0.05). No difference was observed in the socioeconomic characteristics and mean daily intakes of zinc between the groups (p > 0.05).

Conclusions

Giardiasis may be a risk factor for zinc deficiency in schoolchildren from northwestern Mexico.

[Prevalence of iron deficiency and iron deficiency anemia in pregnant adolescents from northwest Mexico, 2007-2008]

Iron deficiency anemia (IDA) remains a word public health problem, particularly in children and child-bearing-age women. Iron demands need to be covered by adolescent women due to the increased physical growing, menstruation, pregnancy and fetal growing tissues at this life stage. This study was proposed to investigate the prevalence of iron deficiency and IDA in pregnant adolescent women from Northwestern Mexico. Participated 186 women under 19 years old during the first or second trimester of pregnancy who attended the local health institutions in Hermosillo Sonora. Questionnaires and 24 hr recalls were administered to collect socioeconomic and dietary information respectively. Hemoglobin (Hb), hematocrit, ferritin and eritrocytic protoporphyrin were measured. Hb and ferritin values were used to categorize the recruited women into normal (37.4%), iron deficient (55.5%) and IDA (7.1%) groups. Six and seven women showed moderated and light anemia status in the IDA group. Fe and fiber intake and weeks of pregnancy were associated with the biochemical indicators of iron at least in two women groups. The high percentage of iron deficient women in this study is demanding the identification and attention of maternal factors and food habits that are risk of iron deficiency in pregnant women.

Impact of Giardia intestinalis on vitamin a status in schoolchildren from northwest Mexico

We conducted a cross-sectional study in northwest Mexico in order to investigate the association between giardiasis and serum vitamin A in 40 Giardia-infected and 70 Giardia-free schoolchildren who were covered by a regional school breakfast program. There were no significant differences in age, Z-scores for nutritional indices of height for age, weight for age, or weight for height, socioeconomic conditions (employment and education of the parents, household conditions, sanitation facilities, type of drinking water, and family income), and mean daily intakes of vitamin A in the Giardia-free (899 +/- 887 microg) and the Giardia-infected (711 +/- 433 microg) groups. A higher concentration of serum retinol was found in the Giardia-free group than in the Giardia-infected group (0.75 micromol/L versus 0.61 micromol/L, respectively; p < 0.0001). Giardia-infected children were more likely to be vitamin A-deficient than the Giardia-free children (OR = 3.2; 95% CI = 1.2-8.5). Although 95% of the children met the daily-recommended intakes of vitamin A, half of them showed subclinical vitamin A deficiency. It is recognized that vitamin A deficiency is multifactorial and giardiasis was a factor significantly associated with this deficiency in this study. Mexican program developers and policymakers should be aware about the distinction between dietary deficiencies and deficiency diseases when current national program strategies for parasitic control and vitamin A supplementation are redesigned.

Validation of a 7-day physical activity diary against doubly-labelled water

BACKGROUND

The assessment of physical activity intensity and duration is essential for understanding group activity patterns.

METHODS

The present study evaluated the validity of measurement of total energy expenditure (TEE) and physical activity level (PAL) using a categorized physical activity diary. In 29 young healthy men, aged 18-27 years, with body mass index range 21-43 kg m(-2), TEE using doubly-labelled water (DLW), resting metabolic rate (RMR) by indirect calorimetry, physical activity level (PAL defined as TEE/RMR) and activity pattern, timing and level from 7-day physical activity diaries were determined.

RESULTS

TEE by DLW and estimated by activity diary were correlated (r = 0.61, p = 0.005). The mean underestimation of TEE by the activity diary compared with the DLW method was 2.50 +/- 0.72 MJ day(-1). Sedentary (lying, sitting and standing) time averaged 18 h day(-1) and was negatively correlated with PAL (r = -0.44, p = 0.018) whilst time spent in light intensity activity (5 h day(-1)) was positively correlated (r = 0.51, p = 0.005).

CONCLUSIONS

It is concluded that the categorized physical activity diary measured TEE with limited accuracy but presents an inexpensive, convenient method of discriminating individual and group physical activity patterns.

Prevalence of malnutrition and associated metabolic risk factors for cardiovascular disease in older adults from Northwest Mexico

This cross-sectional study assessed the prevalence of malnutrition and several metabolic risk factors for cardiovascular disease in 287 apparently healthy older adults from Northwest Mexico. Also, the impact of overweight and obesity on metabolic risk factors was assessed. Nutritional status was determined using serum albumin levels and anthropometry. Vitamin status was also assessed. Metabolic risk factors for cardiovascular disease were evaluated. The prevalence of undernutrition was 15.3%. Also, vitamin E deficiency was common (18%). On the contrary, 44.9% of men and women were in overweight and 24% were obese. A 50.9% of the older adults had hypertension, 52.6% hypercholesterolemia (HC), 38.3% hypertriglyceridemia (HTG), 26.1% impaired fasting glucose and 26.1% impaired glucose tolerance (IGT). HC and low-density-lipoprotein-cholesterol (LDL-C) were significantly more prevalent in women than in men. Mean adjusted values of fasting glucose, high-density-lipoprotein-cholesterol (HDL-C), total cholesterol (TC)/HDL-C ratio > or = 5, triglycerides (TG) and diastolic blood pressure (DBP) were significantly higher in subjects with body mass index (BMI) > or = 25.0 kg/m(2). Undernutrition, obesity and vitamin E deficiency, as well as several metabolic risk factors for cardiovascular disease coexisted in this studied group. Overweight and obesity were the most prevalent findings. BMI > or = 25 kg/m(2) was the common factor explaining most of the metabolic abnormalities. However, due to the sample size and the design of the study, the results must be seen with caution and cannot be generalized.

[Validity of an equation based on anthropometry to estimate body fat in older adults]

A prediction equation to estimate body fat mass from skinfold thickness for healthy elderly was developed using a four compartmental (4C) model as criterion method. This study included 202 subjects = 60 y old. The measurements of total body water, bone mineral content and body density were included in the 4C model equation. Total sample was randomly partitioned. Sub-sample one was used to design the equations, which were applied in sub-sample two. Its accuracy and precision was evaluated by lineal regression analysis and the bias by Bland and Altman analysis and simple lineal regression. The best model included body mass, sex and the calf and triceps skinfolds thicknesses, with an R2, standard error of the estimate and Cp of 0.85, 3.2 and 3.2, respectively. When the equation was applied in sub-sample two, it was accurate and precise, it showed no significant deviation from the line of identity (the intercept was no significantly different from zero, P>0.05), and slope was different from cero (or similar to 1) (P<0.05). Fat mass by the equation accounted for 86% of the variability of the mean fat mass estimated by the 4C model, having a low standard error of the estimate (3.2 kg) and low pure error (3.1 kg). The new equation was accurate and precise as well as free of significant bias in men and women together and for separately. This equation can be a good option to estimate fat mass in elderly men and women with similar physical characteristics to subjects of this study, and it can be used in clinical and epidemiological studies in this growing group.

Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults

BACKGROUND

The study of body composition in specific populations by techniques such as bio-impedance analysis (BIA) requires validation based on standard reference methods. The aim of this study was to develop and cross-validate a predictive equation for bioelectrical impedance using air displacement plethysmography (ADP) as standard method to measure body composition in Mexican adult men and women.

METHODS

This study included 155 male and female subjects from northern Mexico, 20-50 years of age, from low, middle, and upper income levels. Body composition was measured by ADP. Body weight (BW, kg) and height (Ht, cm) were obtained by standard anthropometric techniques. Resistance, R (ohms) and reactance, Xc (ohms) were also measured. A random-split method was used to obtain two samples: one was used to derive the equation by the "all possible regressions" procedure and was cross-validated in the other sample to test predicted versus measured values of fat-free mass (FFM).

RESULTS AND DISCUSSION

The final model was: FFM (kg) = 0.7374 * (Ht2 /R) + 0.1763 * (BW) - 0.1773 * (Age) + 0.1198 * (Xc) - 2.4658. R2 was 0.97; the square root of the mean square error (SRMSE) was 1.99 kg, and the pure error (PE) was 2.96. There was no difference between FFM predicted by the new equation (48.57 +/- 10.9 kg) and that measured by ADP (48.43 +/- 11.3 kg). The new equation did not differ from the line of identity, had a high R2 and a low SRMSE, and showed no significant bias (0.87 +/- 2.84 kg).

CONCLUSION

The new bioelectrical impedance equation based on the two-compartment model (2C) was accurate, precise, and free of bias. This equation can be used to assess body composition and nutritional status in populations similar in anthropometric and physical characteristics to this sample.

Effect of the extrusion on functional properties and mineral dialyzability from Phaseolus vulgaris bean flour

The effects of extrusion conditions on cooking degree, flour dispersion viscosity and mineral potential availability of extruded bean flour were studied. Phaseolus vulgaris beans of the agronomic cultivar "Flor de mayo" were ground and dehulled to obtain grits and then extruded at different temperatures (140, 160 and 180 degrees C) and moisture contents (17, 20 and 23%), according to a bifactorial experimental design. Degree of cooking was estimated by water solubility (WS) and specific mechanical energy (SME). The effect of variables on WS and SME were analysed by surface response methodology. Flour dispersion viscosity and mineral availability (estimated by in vitro dialyzability), were also evaluated on selected samples. Results showed that, within the ranges of the variables used for this study, only the effect of temperature was significant on the degree of cooking. No direct correlation was observed between water solubility and SME, although a maximum value of WS corresponded to a range of SME values of 400-500 J/g was observed. Dispersion viscosity decreases as WS increases, so if high calorie density is desired, for instance in order to produce a cream soup formula, bean grits should be extruded at high temperature and as low moisture as possible, in our case 180 degrees C and 17% moisture. On the other hand, the effects of extrusion variables on iron and zinc dialyzability were not much affected.

Body composition by the four-compartment model: validity of the BOD POD for assessing body fat in mexican elderly

OBJECTIVE

The aims of this study were to validate BOD POD in a wide sample of healthy and independent Mexican elderly men and women subjects using the 4 compartment (4C) model as the reference method, and to evaluate the assumptions of the densitometric two-compartment (2C) model.

DESIGN

Cross-sectional study designed to assess body composition and validation of a method based on 2C model (BOD POD).

SETTING

Urban and rural regions of Sonora, Mexico.

SUBJECTS

Two hundred and two free-living subjects >or=60 years old were completed in this study.

METHODS

Body density and body fat were measured by the BOD POD, total body water by deuterium dilution and total body bone ash by dual energy X-ray absorptiometry. Body composition was determined using Baumgartner's equation.

RESULTS

Percent body fat by the 4C model was 31.2 and 42.5% in men and women, respectively (P<0.001). Group mean accuracy of body fat by BOD POD against that of the 4C model showed an effect of sex (P<0.001), but not the method (P=0.27). Results of individual accuracy showed no significant difference with the identity line and the slope was significantly different from zero or a slope similar to one. Precision assessed by model R (2) was high for all subjects and for men and women by separate. The standard error of the estimate was low for all and for men and women by separate. Bland and Altman analysis showed no significant bias.

CONCLUSION

The BOD POD technique is a valid and reliable method compared to the 4C model and it could be applied in subjects with similar physical and anthropometric characteristics to subjects of this study.

Reduction in liver-related hospital admissions and deaths in HIV-infected patients since the year 2002

Since the advent of highly active antiretroviral therapy (HAART), complications of chronic liver disease (CLD) have emerged as one of the leading causes of hospital admission and death among HIV-infected patients with chronic hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infections. The impact of CLD on hospital admissions and deaths in HIV-infected patients attended at one reference HIV hospital in Madrid during the last 9 years was analysed. All clinical charts from January 1996 to December 2004 were retrospectively examined. Demographics, discharge diagnosis, complications during inhospital stay and causes of death were recorded. A total of 2527 hospital admissions in 2008 distinct HIV-infected persons were recorded. Overall, 84% were iv drug users; mean age was 37 years and the mean CD4 count was 224 cells/muL. Both mean age and CD4 count significantly increased during the study period (P < 0.01). Overall, 42% of hospitalized patients were on antiretroviral therapy. Decompensated CLD was the cause of admission and/or developed during hospitalization in 345 patients (14%). Admissions caused by decompensated CLD increased significantly from 9.1% (30/329) in 1996 to 26% (78/294) in 2002. A significant steady decline occurred since then, being 11% (29/253) in the year 2004. Similarly, inhospital liver-related deaths were 9% (5/54) in 1996, peaked to 59% (10/17) in 2001 and declined to 20% (3/15) in the year 2004. Chronic hepatitis C was responsible for admissions and/or deaths in 73.5% of CLD cases. In conclusion, the rate of liver-related hospital admissions and deaths among HIV-infected patients peaked in the year 2002 and has steadily declined since then. A slower progression to liver cirrhosis in patients on HAART, avoidance of hepatotoxic antiretroviral drugs and more frequent use of anti-HCV therapy in HIV/HCV-coinfected patients could account for this benefit.

Effect of a probiotic food as an adjuvant to triple therapy for eradication of Helicobacter pylori infection in children

OBJECTIVE

Current recommendations for treatment of Helicobacter pylori infection include a proton pump inhibitor in combination with two antibiotics. We evaluated the potential activity of a probiotic food as an adjuvant to antibiotic triple therapy for eradication of H. pylori infection in children from Buenos Aires, Argentina.

METHODS

Sixty-five children who tested positive for H. pylori, as diagnosed by (13)C-urea breath test and endoscopy, were included in this study. Patients were randomized to receive 1-wk triple therapy plus probiotic food (treated group) or milk placebo (control) that was administered for 3 mo. Probiotic food consisted of 250 mL of a commercial yogurt containing Bifidobacterium animalis and Lactobacillus casei (10(7) colony-forming units/mL). Post-treatment urea breath test controls were performed 1 and 3 mo after the end of triple therapy.

RESULTS

We found no significant differences in H. pylori eradication rates (ERs) at 1 and 3 mo between the treated group (ER = 45.5% and 42.4%) and the control group (ER = 37.5% and 40.6%). Relative risks between groups were 0.87 (95% confidence interval 0.58-1.32, P = 0.345) in the first month and 0.97 (95% confidence interval 0.64-1.46, P = 0.542) in the third month.

CONCLUSIONS

We could not demonstrate an adjuvant effect of the studied probiotic food to triple therapy in the eradication of H. pylori infection in children in Buenos Aires, Argentina. However, we found lower ERs than those reported for the same therapeutic scheme in developed countries, indicating that bacterial resistance and alternative therapeutic strategies should be studied.

Role of the employment status and education of mothers in the prevalence of intestinal parasitic infections in Mexican rural schoolchildren

Background

Intestinal parasitic infections are a public health problem in developing countries such as Mexico. As a result, two governmental programmes have been implemented: a) "National Deworming Campaign" and b) "Opportunities" aimed at maternal care. However, both programmes are developed separately and their impact is still unknown. We independently investigated whether a variety of socio-economic factors, including maternal education and employment levels, were associated with intestinal parasite infection in rural school children.

Methods

This cross-sectional study was conducted in 12 rural communities in two Mexican states. The study sites and populations were selected on the basis of the following traits: a) presence of activities by the national administration of albendazole, b) high rates of intestinal parasitism, c) little access to medical examination, and d) a population having less than 2,500 inhabitants. A total of 507 schoolchildren (mean age 8.2 years) were recruited and 1,521 stool samples collected (3 per child). Socio-economic information was obtained by an oral questionnaire. Regression modelling was used to determine the association of socio-economic indicators and intestinal parasitism.

Results

More than half of the schoolchildren showed poliparasitism (52%) and protozoan infections (65%). The prevalence of helminth infections was higher in children from Oaxaca (53%) than in those from Sinaloa (33%) (p < 0.0001). Giardia duodenalis and Hymenolepis nana showed a high prevalence in both states. Ascaris lumbricoides, Trichuris trichiura and Entamoeba hystolitica/dispar showed low prevalence. Children from lower-income families and with unemployed and less educated mothers showed higher risk of intestinal parasitism (odds ratio (OR) 6.0, 95% confidence interval (CI) 1.6–22.6; OR 4.5, 95% CI 2.5–8.2; OR 3.3, 95% CI 1.5–7.4 respectively). Defecation in open areas was also a high risk factor for infection (OR 2.4, 95% CI 2.0–3.0).

Conclusion

Intestinal parasitism remains an important public health problem in Sinaloa (north-western Mexico) and Oaxaca (south-eastern Mexico). Lower income, defecation in open areas, employment status and a lower education level of mothers were the significant factors related to these infections. We conclude that mothers should be involved in health initiatives to control intestinal parasitism in Mexico.