Body Mass Index and Its Relationship with Disability, Chronic Diseases and Frailty in Older People: A Comparison of the Lipschitz and Who Classifications.

BACKGROUND: Anthropometric parameters are closely associated with the pathophysiology of frailty and with clinic and functional parameters assessed for its diagnosis. OBJECTIVE: To evaluate the possible association of the nutritional status of older people as assessed by Body Mass Index (BMI) and functional disability, self-reported chronic diseases and frailty, comparing the use of two different classifications of BMI. DESIGN: Cross-sectional study. SETTING: The sample was selected among community-dwelling older people from the city of Ribeirão Preto/ Brazil. PARTICIPANTS: 326 independent older people (mean age 73.8±6.4 years) who participated in the FIBRA (Frailty in Brazilian Older People) study. MEASUREMENTS: Weight and height were collected for BMI analysis and frailty criteria were applied according to Fried et al. Participants were also evaluated for self-reported activities of daily living (Katz Index and Lawton and Brody Scale), and the presence of chronic diseases. RESULTS: The prevalence of frailty was 12.3%. Regardless of the classification of BMI applied, most of the sample was classified as overweight (50.9% and 39.3% in the Lipschitz and WHO classifications, respectively). For both classifications, low weight was the only BMI classification associated with frailty status (OR Lipschitz: 4.12(1.53-11.14); OR WHO: 6.21 (1.26-30.58). Comorbidities and dependence in activities of daily living (ADLs) were associated with BMI ≥ 30kg.m2. CONCLUSION: Regardless of the classification adopted, low weight is associated with frailty. However, when the WHO stratification is employed, high BMI is also associated to increased functional disability and the presence of comorbidities, coexisting factors of frailty.

Bioelectrical impedance with different equations versus deuterium oxide dilution method for the inference of body composition in healthy older persons.

BACKGROUND: There is no consensus regarding the accuracy of bioimpedance for the determination of body composition in older persons. OBJECTIVE: This study aimed to compare the assessment of lean body mass of healthy older volunteers obtained by the deuterium dilution method (reference) with those obtained by two frequently used bioelectrical impedance formulas and one formula specifically developed for a Latin-American population. DESIGN: A cross-sectional study. PARTICIPANTS: Twenty one volunteers were studied, 12 women, with mean age 72±6.7 years. SETTING: Urban community, Ribeirão Preto, Brazil. MEASUREMENT: Fat free mass was determined, simultaneously, by the deuterium dilution method and bioelectrical impedance; results were compared. In bioelectrical impedance, body composition was calculated by the formulas of Deuremberg, Lukaski and Bolonchuck and Valencia et al. RESULTS: Lean body mass of the studied volunteers, as determined by bioelectrical impedance was 37.8±9.2 kg by the application of the Lukaski e Bolonchuk formula, 37.4±9.3 kg (Deuremberg) and 43.2±8.9 kg (Valencia et. al.). The results were significantly correlated to those obtained by the deuterium dilution method (41.6±9.3 Kg), with r=0.963, 0.932 and 0.971, respectively. Lean body mass obtained by the Valencia formula was the most accurate. CONCLUSION: In this study, lean body mass of older persons obtained by the bioelectrical impedance method showed good correlation with the values obtained by the deuterium dilution method. The formula of Valencia et al., developed for a Latin-American population, showed the best accuracy.

Body composition assessment of undernourished older subjects by dual-energy x-ray absorptiometry and bioelectric impedance analysis.

BACKGROUND: The prevention and treatment of diseases related to changes in body composition require accurate methods for the measurement of body composition. However, few studies have dealt specifically with the assessment of body composition of undernourished older subjects by different methodologies. OBJECTIVES: To assess the body composition of undernourished older subjects by two different methods, dual energy x-ray absorptiometry (DXA) and bioelectric impedance (BIA), and to compare results with those of an eutrophic group. DESIGN: The study model was cross-sectional; the study was performed at the University Hospital of the School of Medicine of Ribeirão Preto, University of São Paulo, Brazil. PARTICIPANTS: Forty-one male volunteers aged 62 to 91 years. The groups were selected on the basis of anamnesis, physical examination and nutritional assessment according to the Mini Nutritional Assessment (MNA) score. Body composition was assessed by DXA and BIA. RESULTS: Body weight, arm and calf circumference, body mass index (BMI), fat free mass (FFM) and fat mass (FM) were significantly lower in the undernourished group as compared to the eutrophic group. There were no significant differences between FFM and FM mean values determined by DXA and BIA in both groups, but the agreement between methods in the undernourished group was less strong. CONCLUSION: Our results suggest caution when BIA is to be applied in studies including undernourished older subjects. This study does not support BIA as an accurate method for the individual assessment of body composition.

Salt and insulin sensitivity after short and prolonged high salt intake in elderly subjects.

Salt sensitivity and insulin resistance are correlated with higher cardiovascular risk. There is no information about changes in salt sensitivity (SS) and insulin sensitivity (IS) after a chronic salt overload in humans. The aim of this study was to evaluate these parameters in the elderly. Seventeen volunteers aged 70.5 +/- 5.9 years followed a low-salt diet (LSD) for 1 week and a high-salt diet (HSD) for 13 weeks. We evaluated SS after one week (HSD1) and after 13 weeks (HSD13), and subjects' IS and lipids on their usual diet (UD) at HSD1, and at HSD13. Blood pressure (BP) was measured at each visit and ambulatory blood pressure monitoring (ABPM) was performed twice. SS was the same at HSD1 and HSD13. Systolic BP was lower on LSD than on UD (P = 0.01), HSD1 (P < 0.01) and HSD13 (P < 0.01). When systolic and diastolic BP were evaluated by ABPM, they were higher at HSD13 during the 24-h period (P = 0.03 and P < 0.01) and during the wakefulness period (P = 0.02 and P < 0.01) compared to the UD. Total cholesterol was higher (P = 0.04) at HSD13 than at HSD1. Glucose and homeostasis model assessment (HOMA) were lower at HSD1 (P = 0.02 and P = 0.01) than at HSD13. Concluding, the extension of HSD did not change the SS in an elderly group. The higher IS found at HSD1 did not persist after a longer HSD. A chronic HSD increased BP as assessed by ABPM.

Salt and insulin sensitivity after short and prolonged high salt intake in elderly subjects

Salt sensitivity and insulin resistance are correlated with higher cardiovascular risk. There is no information about changes in salt sensitivity (SS) and insulin sensitivity (IS) after a chronic salt overload in humans. The aim of this study was to evaluate these parameters in the elderly. Seventeen volunteers aged 70.5 ± 5.9 years followed a low-salt diet (LSD) for 1 week and a high-salt diet (HSD) for 13 weeks. We evaluated SS after one week (HSD1) and after 13 weeks (HSD13), and subjects’ IS and lipids on their usual diet (UD) at HSD1, and at HSD13. Blood pressure (BP) was measured at each visit and ambulatory blood pressure monitoring (ABPM) was performed twice. SS was the same at HSD1 and HSD13. Systolic BP was lower on LSD than on UD (P = 0.01), HSD1 (P < 0.01) and HSD13 (P < 0.01). When systolic and diastolic BP were evaluated by ABPM, they were higher at HSD13 during the 24-h period (P = 0.03 and P < 0.01) and during the wakefulness period (P = 0.02 and P < 0.01) compared to the UD. Total cholesterol was higher (P = 0.04) at HSD13 than at HSD1. Glucose and homeostasis model assessment (HOMA) were lower at HSD1 (P = 0.02 and P = 0.01) than at HSD13. Concluding, the extension of HSD did not change the SS in an elderly group. The higher IS found at HSD1 did not persist after a longer HSD. A chronic HSD increased BP as assessed by ABPM.

Effect of fluid and food intake on the body composition evaluation of elderly persons.

BACKGROUND: Several studies have shown that liquid and food intake interfere with the evaluation of body composition in adults. However, since there are no reports about this interference in the elderly population, the need to fast for this evaluation may be dispensable. OBJECTIVES: The objective of the present study was to assess the influence of liquid and solid food on the measurement of body composition by bioelectrical impedance analysis (BIA) and by dual energy X-ray absorptiometry (DXA). DESIGN: Forty-one male volunteers aged 62 to 87 years participated in the study. The subjects were submitted to evaluation of body composition by DXA and BIA under fasting conditions and 1 hour after the ingestion of breakfast (500 ml of orange juice and one 50 g bread roll with butter). RESULTS: There was no significant difference in the variables fat-free mass (FFM) or fat mass (FM) between the fasting condition and the evaluation performed 1 hour after the meal as measured by BIA or DXA. There was also no significant difference when the same variables were compared between methods. CONCLUSION: In the present study, the ingestion of 500 ml orange juice and of one bread roll with butter by elderly subjects did not affect the results of the parameters of body composition determined by BIA or DXA. Thus, these exams could be performed without the rigor of fasting, often poorly tolerated by the elderly.

Dietary sodium intake and cardiac nerve cell hypertrophy in Wistar rats

We determined the effect of dietary sodium intake (0.15 and 8 per cent NACl) on the cardiac neuron size of normotensive 3-week old Wistar rats. An increase in dietary sodium for 48 weeks induced an increase in neuronal size. The number of large neurons (larger than 500 muM2) increased significantly (chi-square test) in rats ingesting 8 per cent NaCl in their food. The rats presented hypertension (128 ñ 9 vs 134 ñ 16 mmHg; difference not significant, Student t-test) and a statistically significant increase in cardiac muscle mass (1.6 ñ 0.1 vs 2.0 ñ 0.2 mg/g of rat). We conclude that food sodium can significantly increase cardiac nerve cell size and this trophic response occurs concomitantly with an increase of cardiac muscle mass.