Ivan Mendoza

Bioelectrical impedance spectroscopy (BIS) in young children with acute and semi-acute hydration disorders: Potentials and limitations

This study aimed to evaluate the feasibility and reliability of bioelectrical impedance spectroscopy in young children suffering of acute hydrational disorders. Whole body and segmental measurements were carried out in a group of 42 of children aged 4 to 147 months, using a BIS analyzer (Xitron 4000B). This phase of the study involved several hundred of BIS measurement, which showed the feasibility of using this technique in young children. Using the sweep mode and the modeling software provided for the manufacturer of the instrument, the resistance of the extracellular (RECW) and intracellular (RICW) compartment was calculated. Correlation coefficient (r) and technical error of measurement (TEM) were obtained from paired BIS measurements. RECW showed to be highly reproducible (r = 0.99), with a relatively low TEM (from 1 to 3.5%), across all segments. The reliability was markedly lower respect to RICW, which shows the potential application of BIS technique even in critically ill young child populations.

A comparison of body fat estimates using anthropometry and bioelectrical impedance analysis with distinct prediction equations in elderly persons in the republic of Guatemala.

Bioelectrical impedance analysis (BIA) has been proposed as a technique to estimate body composition. Its application has extended beyond the clinical setting, however, it remains to be determined if the BIA prediction formulas published to date provide comparable body composition estimates in elderly populations. The objective of this study was to compare the estimates of body fat derived from published prediction equations in a developing countrys population such as Guatemala. A total of 234 elderly persons were studied (108 males and 126 females), with ages of 78 +/- 7 and 77 +/- 8 (mean +/- SD) yr, respectively. The height and weight averaged 156.4 +/- 7.9 and 144.0 +/- 7.0 cm, and 54.5 +/- 9.4 and 49.4 +/- 10.6 kg, for males and females, respectively. Measurements included skinfolds (triceps, biceps, subscapular, and suprailiac), and body resistance (BIA). Body fat estimates were derived from four BIA-prediction formulas and three equations based on anthropometry. Mean percent body fat estimates for the overall population obtained from anthropometry and BIA prediction formulas ranged from 22 to 50%. Females had higher estimates compared to males without regard for the method used. Highly significant intermethod correlations were seen, but differences in fat estimation among prediction formulas were noticed and the magnitude of the differences were BIA-formula dependent.

Comparative body composition estimates for institutionalized and free-living elderly in metropolitan areas of the republic of Guatemala

Abstract Elderly populations from developing countries represent two-thirds of the whole worlds elderly population; however very little is known respect their health and nutritional status. Guatemala has a population of almost 10 million inhabitants, and approximately 6% is composed of persons over 60 y. The objectives of the present study were to evaluate the nutritional status and the body composition profile in a group of 234 Guatemalan elderly subjects; and to document any differences between institutionalized (I) (n = 174) and ambulatory free-living elderly subjects (FL) (n = 60). A total of 108 were male and 126 female. The mean (± SD) ages of male and female were respectively, 78 ± 7 and 77 ± 8 y; the I group tended to be older than to FL: 79 ± 8 vs 74 ± 8 y. Anthropometric measurements included weight, height, mid-arm circumference and four skinfolds (triceps, biceps, subscapular and suprailiac); these were complemented with bioelectrical impedance analysis indices: resistance and reactance. The overall means (± SD) in terms of height, weight and BMI for males and females, respectively were 156.4 ± 8.0 and 144 ± 7 cm; 54.5 ± 9.4 and 49.4 ± 10.6 kg; and 22.2 ± 2.9 and 23.8 ± 4.3 kg/m 2 . As it was expected males were taller and heavier compared to women. After adjusting for age, sex and setting, I younger elderly were fattier than their counterparts (FL); however, older FL groups differed only in having more weight and greater mid-arm muscle area compared to I. An age effect was observed principally in older I women, showing less weight and fat than younger groups, while free-living older groups had more weight and greater BIA-body fat compared to younger FL. In conclusion, I and FL differed in terms of body composition, and the differences were age dependent. BIA and anthropometry showed high correspondence and to be sensitive to demonstrate the findings in the expected direction. Due to the high specificity of the published BIA-equations, attention should be paid when estimating body composition in elderly populations of developing countries.

Weight of foods and number of portions consumed are not proxies for expressing nutrient intakes in field studies.

In order to determine whether simplified indicators for usual consumption of selected food groups, specifically those derived from either the percentage of the number of daily portions, the percentage of total daily weight consumed, or both, could serve as proxies for the conventional expression of daily energy intake, these indicators were computed and compared from food-frequency data in a data set. Food consumption was reported in frequency categories and portion sizes per month, per week, or per day, and the cumulative sum was divided by 365 to provide a daily average. The survey was done in the township of Santa Cruz and three hamlets of a rural county seat in Guatemala. Data from food-frequency questionnaires from 269 individuals (55 men and 214 women aged 16 to 86 years) were analyzed. For foods of plant origin, the percentage of total energy, percentage of total food weight, and percentage of total number of portions consumed showed low correlations (r < .45). When subdivided into specific foods and food groups (fruits and vegetables, red meat, etc.), marked differences were revealed across sites and among different indicators of consumption. Despite the simplicity of calculation, neither the percentage of weight of food in a group nor the percentage of portions consumed could serve reliably as proxies for their contributions to the percentage of total energy in this rural population in Guatemala.