Energy expenditure and wasting in human immunodeficiency virus infection

Energy balance in cystic fibrosis when stable and during a respiratory exacerbation

BACKGROUND AND AIMS

Undernutrition is common in young adult patients with cystic fibrosis (CF) and implies an imbalance between energy intake and total energy expenditure (TEE). The aim of this study was to measure energy intake and TEE expenditure in a group of patients when they were clinically stable at home and during an exacerbation of respiratory symptoms when they were in hospital receiving intravenous antibiotics.

METHODS

Eleven patients aged between 15 and 40 years with moderate respiratory disease, mean FEV(1) 51.4% predicted took part. An exacerbation was defined as>15% decrease in FEV(1), an increase in sputum production and a decision to treat in hospital with intravenous antibiotics. Resting energy expenditure (REE) was measured using indirect calorimetry and energy intake by 3 day food diaries. TEE expenditure was measured using 24 h heart rate and doubly isotopically labelled water.

RESULTS

REE was higher at the beginning of an exacerbation than the end, P<0.05. There was no significant difference in TEE during the stable period compared to the exacerbation 10.53(2.39)MJ/day compared to 8.77(1.59)MJ/day using doubly isotopically labelled water. There was no difference in energy intake during the exacerbation compared to the stable period, 11.19(2.31)MJ/day compared to 11.77(2.30)MJ/day.

CONCLUSIONS

There was no difference in TEE and energy intake when patients were unwell in hospital compared to when they were stable at home despite an increase in REE.

Progressive resistive exercise interventions for adults living with HIV/AIDS

BACKGROUND

Due to medical advancements, many people living with HIV infection in developed countries are living longer (Palella 1998). HIV infection can now present as a chronic illness with an uncertain natural disease history. The changing course of HIV infection has lead to a potential increase in the prevalence and impact of disability in people living with HIV infection. Exercise is one key management strategy used by health care professionals to address impairments (problems with body function or structure as a significant deviation or loss such as pain or weakness), activity limitations (difficulties an individual may have in executing activities such as inability to walk) and participation restrictions (problems an individual may experience in life situations such as inability to work) in this population (World Health Organization 2001). Exercise may also be used to address unwanted changes in weight and body composition in people living with HIV infection. Aerobic exercise has been associated with improvements in strength, cardiovascular function, and psychological status in general populations (Bouchard 1993). Results of a systematic review suggested that aerobic exercise interventions appeared to be safe and may lead to improvements in cardiopulmonary fitness for adults living with HIV/AIDS (Nixon 2002). But what are the effects of progressive resistive exercise (PRE) for adults living with HIV infection?A better understanding of the effectiveness and safety of progressive resistive exercise will enable people living with HIV and their health care workers to practice effective and appropriate exercise prescription, thus contributing to improved overall outcomes for adults living with HIV infection.

OBJECTIVES

To examine the safety and effectiveness of progressive resistive exercise interventions on weight, body composition, strength, immunological/virological, cardiopulmonary and psychological parameters in adults living with HIV infection.

SEARCH STRATEGY

To identify studies to be included in this review, we searched the following databases: MEDLINE, EMBASE, CINAHL, COCHRANE, SCIENCE CITATION INDEX, PSYCHINFO, SOCIOLOGICAL ABSTRACTS, SSCI, ERIC, DAI and HEALTHSTAR. We also reviewed both published and unpublished abstracts and proceedings from major international and national HIV/AIDS conferences such as the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), the Conference on Retroviruses and Opportunistic Infections (CROI), the Infectious Diseases Society of America Conference (IDSA), and the International AIDS Conference (IAC). Reference lists from pertinent articles and books were reviewed, as well as Collaborative Review Group databases. Targeted journals were also hand searched for relevant articles. No language restriction was applied. The search strategy covered literature from 1980-August 2003.

SELECTION CRITERIA

We included studies that were randomized controlled trials (RCTs) comparing progressive resistive exercise interventions with no progressive resistive exercise or another exercise or treatment modality, performed at least three times per week, and lasting at least four weeks among adults (18 years of age or older) living with HIV/AIDS.

DATA COLLECTION AND ANALYSIS

Data collection forms were used by reviewers to abstract data pertaining to study design, participants, interventions, outcomes and methodological quality from the studies that met inclusion criteria. Whenever possible, meta-analyses were conducted on outcomes using RevMan 4.2.2 computer software.

MAIN RESULTS

Seven studies met the inclusion criteria for this systematic review. Meta-analysis was limited due to the following differences among the studies: types of exercise interventions, inclusion of co-intervention groups, level of exercise supervision, baseline body composition and testosterone levels of participants, types of outcomes assessed, and methodological quality of the individual studies.Main results indicated that performing progressive resistive exercise or a combination of progressive resistive exercise and aerobic exercise at least three times a week for at least four weeks appears to be safe and may lead to statistically and possibly clinically important increases in body weight and composition. Results also indicate exercise interventions may lead to clinically important improvements in cardiopulmonary fitness. Individual studies included in this review suggest that progressive resistive exercise interventions with or without aerobic exercise also contribute to improvements in strength and psychological status for adults living with HIV/AIDS. Individual studies indicate that progressive resistive exercise or a combination of progressive resistive and aerobic exercise appears to be safe for adults living with HIV/AIDS who are medically stable as a result of no change seen in immunological/virological status. These results are limited to those who continued to exercise and for whom there were adequate follow-up data.

REVIEWERS' CONCLUSIONS

Progressive resistive exercise or a combination of progressive resistive exercise and aerobic exercise appear to be safe and may be beneficial for adults living with HIV/AIDS. These findings are limited by the small number of studies that could be included in meta-analyses, small sample sizes and variable participant withdrawal rates among included studies. Future research would benefit from including participants at various stages of HIV infection, a greater proportion of female participants, and participants in a variety of age groups to increase the generalizability of results. Furthermore, future research would benefit from studies with larger sample sizes that conduct an "intention-to-treat" analysis (analysis of participants based on the groups to which they were originally allocated) to better understand outcomes of participants that withdraw from exercise interventions.

Hyperphagia contributes to the normal body composition and protein-energy balance in HIV-infected asymptomatic men

Wasting can occur at an early stage of HIV infection. Both reduced energy intake and increased resting energy expenditure (REE) have been considered as factors in wasting with predominant lean body mass loss, suggesting disturbances of protein metabolism. Our aim was to study protein-energy metabolism in relation to body composition and oral energy intake in asymptomatic patients with HIV infection but receiving no active antiretroviral therapy. Stable-weight asymptomatic male patients (n = 8) at stage A of HIV infection with a detectable viral load were compared with 9 healthy control men. Protein metabolism was studied in the postabsorptive state using a primed constant infusion of l-[1-(13)C]leucine and l-[2-(15)N]glutamine. REE was studied by indirect calorimetry, body composition by bioelectrical impedance, and energy intake by dietary records. BMI and lean body mass did not differ between patients and controls. In HIV-infected subjects, energy intake, protein breakdown, protein synthesis, and REE were 57% (P < 0.05), 18% (P < 0.05), 22% (P < 0.05) and 14% (P < 0.05) greater than in controls, respectively. REE and protein breakdown were correlated (r = 0.73, P < 0.05). The hormonal profile was normal in HIV-infected subjects with the exception of low urinary C-peptide and plasma reverse triiodothyronine. Plasma interleukin-6 and tumor necrosis factor-alpha were greater than in controls, but energy intake was 1.53 times the REE in the HIV-infected men. Thus, at the asymptomatic stage of HIV infection, increased protein turnover contributes to the increase in the REE. Moderate hyperphagia, which occurred despite increased levels of cytokines, in conjunction with increased protein synthesis maintains a normal body composition, without significant loss of lean body mass.

Physical and Leisure Activity, Body Composition, and Life Satisfaction in HIV-Positive Hispanics in Puerto Rico

Hispanics represent 13% of the U.S. population but account for 19% of the new AIDS cases reported in 2000. The antiretroviral drug therapy used for the treatment of HIV/AIDS may cause lipodystrophy and insulin resistance, among other effects. Physical and leisure activities reduce these effects and improve the emotional and physical well-being of HIV-positive persons. This study describes physical and leisure activities, life satisfaction, depression, and body composition of HIV-positive Hispanics in Puerto Rico and compares body composition, CD4 counts, depression, leisure time, and life satisfaction of participants classified as physically active or inactive. Sixty-eight individuals were evaluated using questionnaires and biophysical measurements. Descriptive statistics and independent t tests were used for data analysis. Physically active participants had higher life satisfaction scores and healthier body composition as compared to those physically inactive. Health professionals must encourage the promotion of a physically active lifestyle among HIV-positive Hispanics.

Nutrient partitioning during treatment of tuberculosis: gain in body fat mass but not in protein mass

BACKGROUND

Tuberculosis is an important cause of wasting. The functional consequences of wasting and recovery may depend on the distribution of lost and gained nutrient stores between protein and fat masses.

OBJECTIVE

The goal was to study nutrient partitioning, ie, the proportion of weight change attributable to changes in fat mass (FM) versus protein mass (PM), during antimycobacterial treatment.

DESIGN

Body-composition measures were made of 21 men and 9 women with pulmonary tuberculosis at baseline and after 1 and 6 mo of treatment. All subjects underwent dual-energy X-ray absorptiometry and deuterium bromide dilution tests, and a four-compartment model of FM, total body water (TBW), bone minerals (BM), and PM was derived. The ratio of PM to FM at any time was expressed as the energy content (p-ratio). Changes in the p-ratio were related to disease severity as measured by radiologic criteria.

RESULTS

Patients gained 10% in body weight (P < 0.001) from baseline to month 6. This was mainly due to a 44% gain in FM (P < 0.001); PM, BM, and TBW did not change significantly. Results were similar in men and women. The p-ratio decreased from baseline to month 1 and then fell further by month 6. Radiologic disease severity was not correlated with changes in the p-ratio.

CONCLUSIONS

Microbiological cure of tuberculosis does not restore PM within 6 mo, despite a strong anabolic response. Change in the p-ratio is a suitable parameter for use in studying the effect of disease on body composition because it allows transformation of such effects into a normal distribution across a wide range of baseline proportion between fat and protein mass.

Physiological and psychological effects of exercise interventions in HIV disease

The use of both aerobic and resistance exercise has been shown to improve physiologic parameters such as strength, endurance, time to fatigue, and body composition in the HIV-infected population. Exercise has also been used successfully to treat psychologic conditions such as depression and anxiety that are common in HIV-infected individuals. However, the effects of exercise on immune function in these individuals are uncertain because of conflicting results found among studies. Additionally, many ventures into this area have been attempted with poor research design, resulting in inconclusive evidence or poor generalizability. The focus of this paper is to review the research that has been performed using exercise as an intervention for HIV-infected persons and to determine what needs to be done next to further our understanding of how the HIV-infected body and mind respond to exercise training.

Avaliação nutricional em pacientes infectados pelo Vírus da Imunodeficiência Adquirida

Pacientes infectados com o Vírus da Imunodeficiência Humana ou com Síndrome da Imunodeficiência Adquirida freqüentemente apresentam desnutrição protéico-energética, com manifestações heterogêneas, as quais dependem do estado de saúde prévio do paciente. O estado nutricional deve ser avaliado e monitorado cuidadosamente para que o plano terapêutico possa ser efetivo. Uma avaliação nutricional abrangente é fundamental; além disso, toda a equipe de profissionais da saúde e os próprios pacientes devem estar atentos para uma ação precoce e integrada.

Tryptophan depletion and HIV infection: a metabolic link to pathogenesis

HIV-1-infected patients have low circulating tryptophan concentrations despite evidence of adequate dietary intake of this essential amino acid. A chronic increase in inducible tryptophan oxidation is the basis of HIV-1-associated tryptophan depletion. This metabolic process results in the irretrievable loss of tryptophan molecules from the available pool. Such sustained disruption of normal tryptophan metabolism over time disturbs the many metabolic processes involving this amino acid, and has been implicated in some features of AIDS pathogenesis. Normal T-cell function is adversely affected by tryptophan depletion, but the extent of the effect in HIV-1-infected patients is still unclear. Attempting to directly supplement tryptophan is not advised given the potential increase in circulating concentrations of neurotoxic intermediates. Although only preliminary data are available, evidence suggests that antiretroviral and nicotinamide treatments can boost plasma tryptophan concentrations in HIV-1-infected patients and impact the secondary effects of tryptophan depletion. Additional study of this metabolism could lead to improved treatment strategies for patients with HIV infection. In this review I focus on the potential links between disturbed tryptophan metabolism and pathogenesis.

Effects of tuberculosis and HIV infection on whole-body protein metabolism during feeding, measured by the [15N]glycine method

BACKGROUND

Tuberculosis (TB) and HIV infection are wasting diseases that frequently occur together and have severe consequences on nutritional status.

OBJECTIVE

The objective was to determine the effects of TB and HIV, separately and together, on protein metabolism.

DESIGN

Protein metabolism was determined in the fed state in 11 healthy control subjects, in 10 patients with HIV infection without TB or other active infection (HIV group), in 10 patients with active TB without HIV infection (TB group), and in 8 patients with HIV infection and active TB (HIVTB group) with the use of oral [(15)N]glycine and measurement of enrichment in urinary urea and ammonia.

RESULTS

Whole-body protein flux and degradation were lower in the HIV group than in the control group (mean flux: 3.53 +/- 0.40 compared with 4.75 +/- 0.97 g. kg lean body mass(-1). 12 h(-1); P = 0.002). Protein flux, synthesis, and degradation were not significantly different between the control group and the TB and HIVTB groups. Net protein balance was strongly anabolic in the control, HIV, and TB groups but was neutral in the HIVTB group (P < 0.001 for comparison between groups).

CONCLUSIONS

HIV infection was associated with a significant down-regulation of whole-body protein flux. TB alone was not associated with abnormal protein metabolism, but net anabolism in the fed state was impaired in the HIVTB group.

The relation between serum leptin levels and body fat mass in patients with active lung tuberculosis

The relationship of leptin to diminished appetite and weight loss has been investigated in many diseases. Diminished appetite and weight loss are the most apparent characteristics of patients with active lung tuberculosis and in this study the relation of leptin to such diminished appetite and weight loss has been investigated in patients with active lung tuberculosis before and after treatment. Twenty-five patients (7 female, 18 male) with active tuberculosis having an age range of 18-70 years (mean 47.48 +/- 15.36 y) and 25 normal individuals (9 female, 16 male) having an age range of 25-71 years (mean 44.60 +/- 13.80 y) were included in this study. Leptin levels, body mass index (BMI), body fat ratio (BFR), and waist hip ratio (WHR) were measured before and after 6 months of antituberculosis treatment. The same measurements were also made in the control group and the results were compared. While the pretreatment BMI (22.02 +/- 4.31 kg/m2) and BFR (16.60% +/- 9.30%) values in the patient group were significantly lower than in the control group, we found no difference in their pretreatment WHR values. Pretreatment leptin levels (3.49 +/- 3.34 microg/L) were significantly higher in patients with tuberculosis than in the control group (2.33 +/- 1.10 microg/L). Leptin levels were found to be significantly increased at the 6th month of antituberculosis treatment (5.65 +/- 5.41 microg/L) than the pretreatment values (p < 0.05). We observed an evident increase in BMI (24.10 +/- 4.87 kg/m2) and BFR (17.51% +/- 9.25%) due to antituberculosis treatment (p < 0.05). This study suggests that leptin has a role in the diminished appetite and weight loss symptoms in patients with active lung tuberculosis.

Total energy expenditure and carbohydrate oxidation are increased in the human immunodeficiency virus lipodystrophy syndrome

To determine whether total energy expenditure (TEE) is increased in the human immunodeficiency virus (HIV) lipodystrophy syndrome, we compared energy expenditure (EE) and substrate oxidation rates in 12 HIV-infected men with lipodystrophy, 7 HIV-infected men without lipodystrophy, and 14 healthy controls. TEE and nutrient oxidation rates were assessed by whole-room indirect calorimetry. Resting energy expenditure (REE) was measured by indirect calorimetry using the open-circuit technique. Body composition was assessed by dual-energy x-ray absorptiometry (DEXA). Insulin sensitivity was measured using the insulin-modified frequently sampled intravenous glucose tolerance test. TEE adjusted for lean body mass (LBM) was significantly higher in the HIV-infected group with lipodystrophy compared to HIV-infected patients without lipodystrophy (2,873.3 +/- 69 v 2,573.9 +/- 92 kcal/d, P =.02) and compared to healthy controls (2,873.3 +/- 69 v 2,404.0 +/- 64 kcal/d, P <.001). REE and sleeping metabolic rate (SMR) adjusted for LBM were also significantly higher in the HIV-infected group with lipodystrophy compared to both HIV-infected and healthy controls. Carbohydrate oxidation rates adjusted for LBM were higher in men with HIV lipodystrophy as compared to healthy controls (362.5 +/- 23 v 250.0 +/- 22 g/d, P = <.01) and tended to be higher as compared to HIV-infected controls (362.5 +/- 23.6 v 297.3 +/- 31 g/d, P =.1). In conclusion, TEE and carbohydrate oxidation are increased in the HIV lipodystrophy syndrome. The increase in TEE appears to be due to increases in REE. The pathogenesis of elevated EE in HIV lipodystrophy and other forms of lipodystrophy remains to be determined.

General nutrition management in patients infected with human immunodeficiency virus

Nutritional management is integral to the care of all patients infected with human immunodeficiency virus (HIV). HIV infection results in complicated nutritional issues for patients, and there is growing evidence that nutritional interventions influence health outcomes in HIV-infected patients. We define levels of nutritional care, and we discuss when patients should be referred to providers (i.e., registered dietitians) with nutritional and HIV expertise.

Calculating energy requirements for men with HIV/AIDS in the era of highly active antiretroviral therapy

OBJECTIVES

1. To determine if resting energy expenditure (REE) adjusted for body composition is elevated in HIV-positive males when compared with healthy controls in the era of highly active antiretroviral therapy. 2. To examine the accuracy of prediction equations for estimating REE in people with HIV. 3. To determine if REE adjusting for body composition is significantly different between those HIV-positive subjects reporting lipodystrophy (LD) or weight loss (>or=5%) and those who are weight stable when compared to controls.

DESIGN

Cross-sectional study.

SETTING

Tertiary referral hospital HIV unit and an outpatient clinic specializing in HIV care.

SUBJECTS

HIV-positive males (n=70) and healthy male controls (n=16).

METHODS

REE was measured using indirect calorimetry. Body composition was assessed using bioelectrical impedance analysis.

RESULTS

1. REE when adjusted for fat-free mass and fat mass using the general linear model (analysis of covariance) was greater in HIV-positive subjects than controls (7258+/-810 kJ, n=70 vs 6615+/-695 kJ, n=16, P<0.05). 2. The Harris and Benedict, Schofield, Cunningham and the two equations previously published by Melchior and colleagues in HIV-positive subjects all gave an estimate of REE significantly different from the measured REE in the HIV-positive subjects, therefore a new prediction equation was developed. The inability of the published equations to predict REE in the different HIV-positive subgroups reflected the heterogeneity in body composition. 3. REE adjusted for fat-free and fat mass was significantly greater in the both the HIV patients who were weight stable and those with lipodystrophy compared with the healthy controls.

CONCLUSION

REE is significantly higher in HIV-positive males when compared with healthy controls. Body composition abnormalities common in HIV render the use of standard prediction equations for estimating REE invalid. When measuring REE in HIV-positive males adjustment steps should include fat-free and fat mass.

HIV-1 protein Vpr suppresses IL-12 production from human monocytes by enhancing glucocorticoid action: potential implications of Vpr coactivator activity for the innate and cellular immunity deficits observed in HIV-1 infection

The HIV-1 protein Vpr has glucocorticoid receptor coactivator activity, potently increasing the sensitivity of glucocorticoid target tissues to cortisol. Patients with AIDS and normal cortisol secretion have manifestations compatible with glucocorticoid hypersensitivity of the immune system, such as suppression of innate and cellular immunities. The latter can be explained by glucocorticoid-induced inhibition of cytokine networks regulating innate and Th1-driven cellular immunity. We demonstrated that extracellularly administered Vpr protein dose-dependently potentiated glucocorticoid-induced suppression of both mRNA expression and secretion of IL-12 subunit p35 and IL-12 holo-protein, but not IL-12 subunit p40 or IL-10, by human monocytes/macrophages stimulated with LPS or heat-killed, formalin-fixed Staphylococcus aureus (Cowan strain 1). This effect was inhibited by the glucocorticoid receptor antagonist RU 486. Also, Vpr changed the expression of an additional five glucocorticoid-responsive genes in the same direction as dexamethasone and was active in potentiating the trans-activation, but not the trans-repression, properties of the glucocorticoid receptor on nuclear factor kappaB- or activating protein 1-regulated simple promoters. Thus, extracellular Vpr enhances the suppressive actions of the ligand-activated glucocorticoid receptor on IL-12 secretion by human monocytes/macrophages. Through this effect, Vpr may contribute to the suppression of innate and cellular immunities of HIV-1-infected individuals and AIDS patients.

Anabolic treatment with GH, IGF-I, or anabolic steroids in patients with HIV-associated wasting

Wasting, and particularly loss of metabolically active lean tissue, contributes to increased mortality, accelerated disease progression, and impairment of strength and functional status in patients with HIV infection. A variety of protein anabolic agents, including growth hormone, insulin-like growth factor-I, testosterone, nandrolone decanoate, oxandrolone, and oxymetholone, have been studied in patients with HIV-associated wasting. Overall, these studies have demonstrated that treatment with protein anabolic agents can increase lean body mass (LBM) and in some cases provide functional benefits and improvements in quality of life. Further research is needed to determine whether such treatment prolongs survival or reduces the overall health care burden of HIV infection. The advances in identification of successful treatments for HIV-associated wasting can provide a model for using these therapies in other catabolic states, including end-stage renal disease, cancer, chronic obstructive pulmonary disease, and cardiac cachexia.

Understanding chronic malnutrition in childhood and old age: role of energy balance research

Undernutrition is commonly associated with chronic disease in children and the elderly. Overnutrition is also, but less commonly, associated with chronic illness. In most diseases malnutrition arises because energy intake does not match energy output. Traditionally, the focus of research has been on abnormalities in energy expenditure, in the belief that these factors were the main determinants of energy imbalance. Recent studies using the doubly-labelled-water method to measure total energy expenditure, combined with more complex study design, have suggested an alternative conclusion. In many chronic diseases patient behaviour, and particularly energy intake, is responsible for energy imbalance and malnutrition. Energy balance studies have therefore provided a useful foundation for the design of strategies aimed at preventing or managing chronic malnutrition. However, modifying patient behaviour is an ambitious undertaking which may not be within the scope of existing clinical nutrition services. A number of non-traditional models of managing chronic malnutrition in children and the elderly are promising. Increasing recognition of the value of systematic review will also provide improved strategies for prevention and management of chronic malnutrition.

Morbidity and nutritional impairment in relation to CD4 count in a Zambian population with high HIV prevalence

The HIV epidemic has greatly increased morbidity in many African cities and severe undernutrition is a prominent feature of the clinical presentation. However, there is little information about the relationship of morbidity or nutritional status to immune damage at a population level. We report a cross-sectional study of morbidity and nutritional status in relation to CD4 count in an impoverished urban community in Lusaka, Zambia, at enrollment into a longitudinal study. Over a 2 month period in 1999, 261 (52%) of 506 adults resident in one area were interviewed and examined. Of 186 adults who consented to testing, 33 (51%) of 65 who were HIV seropositive reported symptoms of disease compared to 39 (32%) of 121 who were HIV seronegative (OR 2.2, 95%CI 1.1-4.2; P=0.02). Peripheral blood CD4 counts in HIV seronegative individuals were broadly similar to norms in developed countries, but 8 (7%) had CD4 counts below 500 cells/microl. Morbidity in HIV seropositive adults was dominated by tuberculosis (n=11), other respiratory infections (5) or persistent diarrhoea (4), and affected individuals had a wide range of CD4 counts. Nutritional impairment was evident in HIV seropositive adults with clinical evidence of opportunistic infection (OI), not those with asymptomatic HIV infection. Unexpectedly, we also noted that systolic blood pressure was reduced progressively in HIV infection and in those with OI. In conclusion, HIV-related morbidity was dominated by a small number of treatable infectious diseases occurring over a wide range of CD4 count. Nutritional impairment was associated with OI.

Nutrient intake and body weight in a large HIV cohort that includes women and minorities

OBJECTIVE

Evaluate the baseline nutrient intake of an HIV positive population that includes significant representation from women and minorities, and determine the relationship between state of disease and nutritional intake.

DESIGN

Baseline data from a prospective study (Nutrition for Healthy Living).

SUBJECTS

Individuals with HIV in the Boston and Rhode Island area (n = 516); 25% were women and 30% were minorities.

METHODS

Nutrient intakes from 3-day food records, which included vitamin/mineral supplements, were estimated by gender and nonwhite vs white categories, after grouping by CD4 lymphocyte counts.

STATISTICAL ANALYSES

Spearman correlation coefficients, Wilcoxon signed rank test, Wilcoxon rank sum test, chi2 test, and restricted cubic spline model were used for data analyses as indicated.

RESULTS

Macronutrient but not micronutrient intake was statistically and inversely associated with decreasing CD4 cell counts. The median intake of micronutrients was higher in the study sample compared with the same age and gender group in NHANES III data; however, 25% to 35% of the women in our study sample had dietary intakes of less than 75% of the DRIs for vitamins A, C, E and B-6, and iron and zinc. White men had statistically higher values of all micronutrients compared with nonwhite men. Body mass index for men and women ranged from 23 to 25.

CONCLUSIONS/APPLICATIONS

Median values for micronutrient intake from food plus vitamin/mineral supplements were adequate in the overall population studied, but a large percent of women and minorities had inadequate nutrient intakes and would benefit from dietary assessment and counseling.

Nutrition and HIV infection

Infection by the human immunodeficiency virus (HIV) is characterized by progressive destruction of the immune system, which leads to recurrent opportunistic infections and malignancies, progressive debilitation and death. Malnutrition is one major complication of HIV infection and is recognized as a significant prognostic factor in advanced disease. Malnutrition is multifactorial and poorly treated during the course of HIV. Even if a standardized approach to the management of active weight loss has not been well established, early nutritional intervention is important in HIV infected patients to maximize gain of lean body mass. From early in the era of highly active antiretroviral therapy (HAART), an initial decreased incidence of malnutrition was noted only in western countries while a variety of changes in the distribution of body fat and associated metabolic abnormalities have been recognized under the banner of lipodystrophy.

The role of exercise in the prevention and treatment of wasting in acquired immune deficiency syndrome

Involuntary weight loss with lean tissue depletion is a serious and AIDS-defining complication of HIV infection. This article explores definitions of AIDS wasting syndrome (AWS), its etiology, methods of assessing body composition, and pharmacological treatments. Recent research literature on the role of exercise in the prevention and treatment of AWS is reviewed. Included are studies of the safety of exercise, the effects of exercise on the immune system, and the effects of exercise on weight gain and body composition as well as studies of exercise in combination with medications and other interventions. Implications for clinical practice are discussed.

Weight loss and body mass index as predictors of HIV disease progression to AIDS in adults. Aquitaine cohort, France, 1985-1997

OBJECTIVE

To assess the performance of weight related nutritional markers (reported involuntary weight loss greater than 10%, measured weight loss and body mass index-BMI-) in predicting HIV disease progression.

DESIGN

Multirisk cohort of HIV-1 infected patients.

METHOD

The three nutritional variables were studied in Cox proportional hazard models as time dependant variables.

RESULTS

The sample included 2376 subjects (median follow up: 43.1 months), of those 675 experienced an AIDS defining event. After adjustment for well known prognostic factors, the reported weight loss greater than 10% tripled the risk of progression to clinical AIDS (Hazard ratio [HR] 3.0. 95% confidence interval [CI] 2.5-3.7). For measured weight loss under 5%. between 5% and 10% and greater than 10% of baseline weight compared with no weight loss, hazard ratios were respectively 1.8 (CI 1.5-2.2), 2.6 (CI 2.1-3.2) and 5.1 (CI 4.1-6.4). The relative risks of AIDS were 1.7 (CI 1.3-2.2) for BMI between 17 kg/m2 and 18.5 kg/m2, 2.6 (CI 1.7-4.0) for BMI between 16 kg/m2 and 17 kg/m2 and 4.7 (CI 3.0-7.4) for BMI under 16 kg/m2.

COMMENTS

Even a limited weight loss measured at a given time during follow up increases the risk of HIV progression; moreover, a simple cross-sectionnal measure of BMI has a good predictive value for subsequent development of clinical disease.

Maternal and infant factors associated with failure to thrive in children with vertically transmitted human immunodeficiency virus-1 infection: the prospective, P2C2 human immunodeficiency virus multicenter study

OBJECTIVE

Many children with human immunodeficiency virus-1 (HIV-1) have chronic problems with growth and nutrition, yet limited information is available to identify infected children at high risk for growth abnormalities. Using data from the prospective, multicenter P2C2 HIV study, we evaluated the relationships between maternal and infant clinical and laboratory factors and impaired growth in this cohort.

METHODS

Children of HIV-1-infected women were enrolled prenatally or within the first 28 days of life. Failure to thrive (FTT) was defined as an age- and sex-adjusted weight z score < or =-2.0 SD. Maternal baseline covariates included age, race, illicit drug use, zidovudine use, CD4+ T-cell count, and smoking. Infant baseline predictors included sex, race, CD4+ T-cell count, Centers for Disease Control stage, HIV-1 RNA, antiretroviral therapy, pneumonia, heart rate, cytomegalovirus, and Epstein-Barr virus infection status.

RESULTS

The study cohort included 92 HIV-1-infected and 439 uninfected children. Infected children had a lower mean gestational age, but birth weights, lengths, and head circumferences in the 2 groups were similar. Mothers of growth-delayed infants were more likely to have smoked tobacco and used illicit drugs during pregnancy. In repeated-measures analyses of weight and length or height z scores, the means of the HIV-1-infected group were significantly lower at 6 months of age (P <.001) and remained lower throughout the first 5 years of life. In a multivariable Cox regression analysis, FTT was associated with a history of pneumonia (relative risk [RR] = 8.78; 95% confidence interval [CI]: 3.59-21.44), maternal use of cocaine, crack, or heroin during pregnancy (RR = 3.17; 95% CI: 1.51-6.66), infant CD4+ T-cell count z score (RR = 2.13 per 1 SD decrease; 95% CI: 1.25-3.57), and any antiretroviral therapy by 3 months of age (RR = 2.77; 95% CI: 1.16-6.65). After adjustment for pneumonia and antiretroviral therapy, HIV-1 RNA load remained associated with FTT in the subset of children whose serum was available for viral load analysis.

CONCLUSIONS

Clinical and laboratory factors associated with FTT among HIV-1-infected children include history of pneumonia, maternal illicit drug use during pregnancy, lower infant CD4+ T-cell count, exposure to antiretroviral therapy by 3 months of age (non-protease inhibitor), and HIV-1 RNA viral load.

The metabolic puzzle during the evolution of HIV infection

Abnormalities in energy, protein, lipid and glucose metabolism have been described in HIV patients since the beginning of the epidemic. With the new antiretroviral agents, nutritional status and survival have improved dramatically. However, since these therapies were introduced, there have been more descriptions of metabolic abnormalities, some of which were similar to and others of which were in conflict with those reported in previous years. This paper reviews the complexity of the metabolic abnormalities in HIV infections before and after the introduction of highly active antiretroviral therapy, and discusses such etiopathogenic mechanisms as secondary infections, antiretroviral drugs and persistent immune activation, which may be involved in these derangements.

Acute phase response and energy balance in stable human immunodeficiency virus-infected patients: a doubly labeled water study

We sought to assess possible associations of the acute phase response with energy balance as a cause of malnutrition in uncomplicated HIV-infection. Seven stable HIV-infected patients and 7 control subjects were followed for 2 weeks for blood chemistry, body composition, total and resting energy expenditure (TEE, REE), heart rate, energy intake, and physical activity; 6 patients were investigated for interleukin-2 receptor. TEE, REE, energy intake, and anthropometric data in patients and control subjects were very similar. However, physical activity, total body potassium, and bioimpedance phase angle were decreased (1.41 +/- 0.08 vs 1.55 +/- 0.9, 152 +/- 10 g vs 191 +/- 37 g, and 6.4 +/- 0.8 degrees vs 7.1 +/- 0.5 degrees; each P < .05), and mean heart rate, fibrinogen, and erythrocyte sedimentation rate were increased in HIV-infected patients (84 +/- 6 bpm vs 76 +/- 8 bpm, 4.3 +/- 1.2 g/L vs 2.5 +/- 0.4 g/L, and 21 +/- 13 mm vs 2 +/- 3 mm; P < .05). The deviation between the measured and the predicted REE in the patient group correlated positively with heart rate and serum interleukin-2 receptor concentrations (r = 0.83 and r = 0.91; P < .05). Possible increases in REE caused by an ongoing acute phase response may be counterbalanced by reduced physical activity that results in normal TEE in HIV infection.

Total energy expenditure in children with obstructive sleep apnoea syndrome

Childhood obstructive sleep apnoea syndrome (OSAS) acts as a check on growth and nutritional status. An increase in sleeping energy expenditure has been proposed as a possible mechanism, but to date, no studies have determined whether energy requirements (total energy expenditure; TEE) are raised in OSAS. The aim of this study was to test the hypothesis that OSAS is associated with increased TEE. Eleven children (mean+/-SD 5.8+/-2.2 yrs of age) with OSAS confirmed by nocturnal polysomnography were each matched with a pair of healthy controls (n=22) of the same age and sex. TEE was measured using the doubly-labelled water method in all subjects. In 10/11 patients TEE was also measured after adenotonsillectomy and changes in TEE assessed. There was no significant difference in TEE between patients (mean+/-SD 325+/-44 kJ x kg(-1) x day(-1)) and controls (339+/-48 kJ x kg(-1) x day(-1)), nor between patients and age- and sex-specific literature data on TEE, using the doubly-labelled water method. Differences in TEE within patients, before versus after surgery, were minor and not statistically significant. This study does not support the hypothesis that obstructive sleep apnoea syndrome in childhood is associated with increased energy requirements, and suggests that alternative explanations for the effect of this syndrome on growth and energy balance should be sought.

Nutrition in the era of highly active antiretroviral therapy

Despite tremendous advances in treatment, persons with human immunodeficiency virus (HIV) infection commonly experience a variety of nutritional problems, such as weight loss, fat redistribution, and obesity. We discuss basic dietary and metabolic problems as they pertain to persons with HIV infection and provide practical suggestions for their management. In all persons, changes in weight are caused by disruptions of energy balance, which can be disturbed by alterations in energy intake (effective ingestion of calories), energy expenditure (use of calories), or both. Factors that contribute to the disturbance of energy balance are discussed in the context of HIV infection. Management of weight loss and weight gain may then be directed at the affected components of energy balance. This information is intended to raise health care providers' attention to nutrition in their patients, including monitoring of weight, dietary issues, and relevant symptoms, and to encourage liaisons with experienced dietitians and exercise trainers.

Assessment of hunger and appetite and their relationship to food intake in persons with HIV infection

Assessments of hunger and/or appetite are common methods of screening for development of illness-related anorexia. There are limited data to determine whether these methods predict actual food intake in persons with HIV disease. Therefore, the authors examined the relationship between self-reported food intake and subjective ratings of hunger and appetite in 31 adults with HIV infection. Participants also indicated presence of additional factors that can decrease amount of food eaten. Subjective ratings of appetite and hunger correlated with each other but not with food intake. Twenty-four additional factors that can affect food intake were reported to be present. The most common were illness-related and factors such as eating with friends or family. These results indicate that measures of hunger and appetite are not sufficient to screen for decreased food intake. Additional factors that can affect food intake should also be included in a comprehensive assessment of adults with HIV infection.

Metabolic Complications of HIV and AIDS

Nutritional problems in the patient with HIV/AIDS may include both wasting and the more recently described lipodystrophy syndromes, which are complex disorders of body composition and metabolism associated with antiretroviral therapy. In this paper we review the pathophysiology and treatment options for both wasting and lipodystrophy.

The effect of plasma human immunodeficiency virus RNA and CD4(+) T lymphocytes on growth measurements of hemophilic boys and adolescents

OBJECTIVE

The investigation examined the associations of plasma human immunodeficiency virus (HIV) RNA and CD4(+) T lymphocytes with height, weight, skeletal maturation, testosterone levels, and height velocity for hemophilic children and adolescents with HIV infection in the Hemophilia Growth and Development Study.

STUDY DESIGN

Two hundred seven participants were evaluated over 7 years.

RESULTS

A threefold increment in baseline plasma HIV RNA was associated with a 0.98-cm decrease in height and a 1.67-kg decrease in weight; 100-cells/microL decrements in baseline CD4(+) were associated with a 2.51-cm decrease in height and a 3.83-kg decrease in weight. Participants with high plasma HIV RNA (>3125 copies/mL) experienced significant delay in achieving maximum height velocity and lower maximum velocity compared with those with low viral load. The high CD4(+) (>243)/low plasma HIV RNA group had earlier age at maximum height velocity compared with the other 3 groups and higher maximum height velocity compared with the low CD4(+)/high plasma HIV RNA and low CD4(+)/low plasma HIV RNA groups. Decrements in CD4(+) were associated with decreases in bone age and testosterone level.

CONCLUSIONS

CD4(+) and HIV RNA were important in predicting growth outcomes.

Urinary cytokines for assessing inflammation in HIV-associated wasting

The relationship between cytokines and HIV-related weight loss has not been well established. Unlike most cytokines that are secreted in a paracrine manner, IL-6, sTNFR-II, and IL-1ra are readily detected in the systemic circulation and serve as markers of the inflammatory response. Twenty-four-hour urine concentrations of these proteins are believed to provide an integrative assessment of their systemic levels over the preceding hours. We sought to determine whether spot measurements of IL-6, sTNFR-II, and IL-1ra could be related to subsequent 24 h concentrations and prior weight loss. Eighteen subjects with severe wasting (average BMI=18+/-3 kg/m2with 19+/-13 kg of weight loss) and six HIV-negative healthy subjects were tested. Compared to values in controls, 24-h urinary concentrations of the three proteins adjusted for creatinine excreted were elevated in 44%, 89%, and 72% of patients, respectively. Twenty-four-hour concentrations were highly correlated with the spot concentrations (r=0.80, 0.87, 0.84, respectively, P<0.001). IL-1ra concentrations (24 h and spot) were correlated with weight loss in the previous 6 months, lifetime rate of weight loss and the 6 month rate of weight loss (spot: r=0.66, 0.73, 0.68, respectively, P< or =0.001). These data suggest that spot urinary collections can be used to estimate 24 h excretion rates. This strategy may be useful in assessing the inflammatory response in HIV-associated wasting.

Tumor necrosis factor, interleukin-6,and epinephrine are associated with hypermetabolism in AIDS patients with acute opportunistic infections

During a 9-day period we investigated body composition, resting energy expenditure (REE), IL-6, TNF, and sTNFR-55 and sTNFR-75 plasma concentrations during infectious complications in 12 patients with HIV disease. At study entry, IL-6 was detectable in 5 and TNF in 10 patients. TNF was closely correlated with sTNFR-75 concentration (r = 0.84, p < 0.001) whereas sTNFR/sTNFR-55 ratio increased throughout the study. TNF concentrations were significantly correlated with the 24-hour excretion of epinephrine and norepinephrine (r = 0.64 and 0.69; each p < 0.01). Compared to expected values REE was increased by 34%. Body cell mass was the single best predictor of REE and explained 72% of its variance. In contrast, the deviation of measured from predicted REE was correlated with TNF and IL-6 concentrations (r = 0.9). We conclude that increased plasma concentrations of cytokines in complicated HIV disease display little biologic variability and relate to hypermetabolism in these patients.

Growth failure in children with HIV infection

Poor growth is reported in as many as 50% of HIV-infected children. HIV infection adversely affects pregnancy outcome; infants born to HIV-infected women have significantly lower mean birth weight and length, regardless of the infants' HIV status, compared with infants born to uninfected women. Pediatric HIV further reduces birth weight. Progressive stunting, that is, proportionately decreased linear and ponderal growth, appears to be the most common abnormality in perinatally infected children and is accompanied by preferential decreases of fat-free or lean body mass. Although data are inconsistent, deficiencies of several micronutrients with the potential to affect growth adversely have been identified, including that of vitamin A. Neuroendocrine abnormalities also occur, including abnormal thyroid, growth hormone/ insulinlike growth factor-1, and adrenal function; however, no consistent endocrine abnormality is observed in HIV-associated growth failure. Infections of the gastrointestinal tract and malabsorption of carbohydrates, fat, and protein are common, but no relationship between these disorders and poor growth has been demonstrated. Despite normal rates of resting and total energy expenditures, the mean daily dietary intake of children with growth failure (GF) appears to be inadequate. Inadequate dietary intake is not the sole cause of GF; dietary supplementation improves weight but does not correct deficits in lean tissue or height. Levels of HIV RNA are greater in children with poor growth compared with infected children with normal rates of growth. How HIV replication impedes growth has not been established but suppression of HIV appears to have a favorable effect on ponderal and linear growth. Further investigations are necessary to evaluate the potential role of anabolic agents for the management of HIV-associated growth failure.

Evidence for association between polycystic ovary syndrome and premature carotid atherosclerosis in middle-aged women

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder characterized by obesity, hyperandrogenism, and insulin resistance. An adverse lipid profile has also been observed in PCOS-affected women, suggesting that these individuals may be at increased risk for coronary heart disease at a young age. The objective of the present study was to evaluate subclinical atherosclerosis among women with PCOS and age-matched control subjects. A total of 125 white PCOS cases and 142 controls, aged >/=30 years were recruited. Collection of baseline sociodemographic data, reproductive hormone levels, and cardiovascular risk factors was conducted from 1992 to 1994. During follow-up (1996 to 1999), these women underwent B-mode ultrasonography of the carotid arteries for the evaluation of carotid intima-media wall thickness (IMT) and the prevalence of plaque. A significant difference was observed in the distribution of carotid plaque among PCOS cases compared with controls: 7.2% (9 of 125) of PCOS cases had a plaque index of >/=3 compared with 0.7% (1 of 142) of similarly aged controls (P=0.05). Overall and in the group aged 30 to 44 years, no difference was noted in mean carotid IMT between PCOS cases and controls. Among women aged >/=45 years, PCOS cases had significantly greater mean IMT than did control women (0.78+/-0.03 versus 0.70+/-0.01 mm, P:=0. 005). This difference remained significant after adjustment for age and BMI (P:<0.05). These results suggest that (1) lifelong exposure to an adverse cardiovascular risk profile in women with PCOS may lead to premature atherosclerosis, and (2) the PCOS-IMT association is explained in part by weight and fat distribution and associated risk factors. There may be an independent effect of PCOS unexplained by the above variables that is related to the hormonal dysregulation of this condition.

Cytokine-driven inflammatory response is associated with the hypermetabolism of AIDS patients with opportunistic infections

BACKGROUND

To assess a possible role of systemic inflammation in the resting metabolic response in AIDS patients with active secondary infections.

METHODS

Fifty-two patients with AIDS-defined criteria and concomitant active infections and 19 healthy subjects were studied. Measurements were as follows: body composition assessed by bioelectrical impedance; resting energy expenditure (REE) by 30-minute indirect calorimetry; cytokine concentrations (IL-6, IFNalpha, TNFalpha, sTNF-R1) by ELISA; C-reactive protein (CRP), erythrocyte sedimentation rate, fibrinogen, and nutritional parameters by standard techniques.

RESULTS

REE adjusted for fat-free mass (REEFFM) was significantly increased in AIDS patients despite 39% of them not being hypermetabolic. The patients were undernourished and were found to have increased levels of acute-phase proteins and increased concentrations of IL-6 and sTNF-R1 relative to controls. REE parameters were positively related to CRP, ESR, ferritin, IL-6, and sTNF-R1 and negatively related to albumin, prealbumin, and transferrin. CRP was an independent predictor of REEFFM in AIDS patients and explained 25% of its variability. Patients with severe inflammation (CRP > or = 37 mg/dL) were significantly hypermetabolic with respect to patients without inflammation (CRP < 6 mg/dL) and had higher levels of IL-6 and sTNF-R1 and lower levels of albumin and prealbumin. Although no significant differences were observed with respect to the infection type, patients with tuberculosis and Pneumocystis carinii infections had higher resting metabolic and inflammatory responses, whereas patients with recurrent bacterial pneumonia were normometabolic and had lower levels of inflammatory markers.

CONCLUSIONS

Resting hypermetabolism observed in AIDS patients with concurrent active infections is related to the presence and severity of systemic cytokine-driven inflammatory response, which could reflect the type of secondary infection.

Fat and energy needs of children in developing countries

The fat requirements of children can be judged according to 4 criteria: 1) the possible obligate needs of fat as a metabolic fuel, 2) the provision of a sufficiently energy-dense diet to meet energy needs, 3) the adequate supply of essential fatty acids, and 4) the supply of sufficient fat to allow adequate absorption of fat-soluble vitamins. In these respects the fat requirements of children in developing countries are probably similar to those of children in affluent nations except for the additional needs imposed by environmental stresses, particularly recurrent infections. In many developing countries, the low energy density of weaning foods appears to be a major contributor to growth faltering and ultimate malnutrition. Evidence from doubly labeled water studies suggests that these diets are adequate when children are healthy but fail to support rapid catch-up growth after diarrhea and other infections. The issues in determining and meeting the fat needs of children in developing countries are illustrated with use of detailed comparative dietary data from a rural community in The Gambia and from Cambridge, United Kingdom. The outstanding feature of the Gambian data is the great importance of breast milk as a source of fat and essential fatty acids up until the end of the second year of life. Weaning foods and adult foods contain low amounts of fat, which causes a sharp transition from adequate fat intakes to probable inadequate fat intakes when children are weaned from the breast. The effects of such low fat intakes, particularly in terms of immune function, require investigation.

Growth velocity, fat-free mass and energy intake are inversely related to viral load in HIV-infected children

The study objectives were to assess the relationships among human immunodeficiency virus (HIV) replication, energy balance, body composition and growth in children with HIV-associated growth failure (GF). Energy intake and expenditure, body composition and level of HIV RNA were measured in 16 HIV-infected children with growth failure (HIV+/GF+), defined as a 12-mo height velocity </= 5th percentile for age, and 26 HIV-infected children with normal rates of growth (HIV+/GF-). Energy intake was measured by repeated 24-h dietary recall, resting energy expenditure (REE) by indirect calorimetry and total energy expenditure (TEE) by the doubly labeled water method. Fat-free mass (FFM) was determined by dual X-ray energy absorptiometry and plasma HIV RNA by the polymerase chain reaction method. The mean plasma HIV RNA content among the HIV+/GF+ group was nearly 1.5 log higher than that of the HIV+/GF- group (4. 89 +/- 1.08 vs. 3.43 +/- 1.64 x10(2) copies/L, P: = 0.009). The mean daily energy intake, and age-adjusted REE and TEE were lower in HIV+/GF+ children (P: = 0.003, 0.06 and 0.16, respectively). HIV+/GF+ children had a mean daily energy deficit of 674 +/- 732 kJ/d compared with HIV+/GF- children who had a mean energy surplus of 1448 +/- 515 kJ/d (P: = 0.030). There were no differences in REE after adjustment for differences in FFM and age using multiple regression analysis (P: = 0.88). There was a significant inverse relationship between FFM and plasma HIV RNA [R:(2) = 0.64, standard error of the estimate (SEE) = 3.23] and between viral load and 12-mo growth velocity (R:(2) = 0.61, SE = 1.51). Viral load and energy intake were also inversely related (R(2) = 0.17, SEE = 573.2, P: = 0. 0125). In HIV-infected children, rate of growth, quantity of FFM and energy intake are closely related to the level of HIV replication. The energy intake of children with HIV-associated GF may not be adequate for supporting normal development of FFM and growth, despite possible decreases in total energy expenditure.

Saúde coletiva e atividade física no contexto de subdesenvolvimento: evidências e perspectivas para superação do atraso

Partindo-se da constatação de que no continente sul-americano, as investigações sobre Atividade Física/Saúde Coletiva têm tomado rumos que mais se aproximam daqueles agravos que acometem pessoas de países desenvolvidos, cujos resultados raramente podem ser acolhidos como referência para nossa realidade, apresentam-se procedimentos metodológicos sobre as formas de mensuração da atividade física desde as medidas diretas realizadas em laboratório, até as indiretas utilizadas para estimativa de consumo calórico de tarefas habituais. Em seguida, o binômio Saúde Coletiva/Exercício Físico é abordado com ênfase para as perspectivas e limitações desta relação em nosso meio. Em momento subseqüente, considerando a possibilidade do padrão epidemiológico de transição, tematiza-se, a partir da literatura técnica pertinente, a prática de exercícios físicos, saúde e agravos infecciosos, apontando-se para algumas vertentes de investigação em nosso meio, com vistas à superação da lacuna apresentada.

Nutritional alterations associated with HIV infection

Nutritional alterations are common in HIV infection. Early studies documented weight loss and protein depletion, a finding associated with body cell mass depletion in untreated patients. The application of highly active antiretroviral therapy has led to a decreased incidence of malnutrition, although altered body fat distribution and metabolic alterations, including hyperlipidemia and insulin resistance, are common sequelae. The development of malnutrition is multifactorial and occurs through changes in caloric intake, nutrient absorption, or energy expenditure. Clinically, malnutrition develops as a result of either starvation or cachexia. Other hormonal and endocrinologic alterations include hypercortisolemia and hypogonadism. The rationale for providing nutritional support to AIDS patients is based upon the assumptions that nutrition status can be improved and that such improvements have clinical benefits. The results of hypercaloric feeding studies, including the use of appetite stimulants, indicate that weight gain is possible but that the weight gained is predominantly fat. In contrast, anabolic agents and resistance training exercise have been shown to promote body cell mass repletion and skeletal muscle gain. Cytokine inhibitors also have been evaluated for the treatment of wasting in HIV infection. Development of combination therapies, preventive therapies, and efficient and cost-effective therapies are current tasks in the field.

Growth failure in children with HIV infection

Poor growth is reported in as many as 50% of HIV-infected children. HIV infection adversely affects pregnancy outcome; infants born to HIV-infected women have significantly lower mean birth weight and length, regardless of the infants' HIV status, compared with infants born to uninfected women. Pediatric HIV further reduces birth weight. Progressive stunting, that is, proportionately decreased linear and ponderal growth, appears to be the most common abnormality in perinatally infected children and is accompanied by preferential decreases of fat-free or lean body mass. Although data are inconsistent, deficiencies of several micronutrients with the potential to affect growth adversely have been identified, including that of vitamin A. Neuroendocrine abnormalities also occur, including abnormal thyroid, growth hormone/ insulinlike growth factor-1, and adrenal function; however, no consistent endocrine abnormality is observed in HIV-associated growth failure. Infections of the gastrointestinal tract and malabsorption of carbohydrates, fat, and protein are common, but no relationship between these disorders and poor growth has been demonstrated. Despite normal rates of resting and total energy expenditures, the mean daily dietary intake of children with growth failure (GF) appears to be inadequate. Inadequate dietary intake is not the sole cause of GF; dietary supplementation improves weight but does not correct deficits in lean tissue or height. Levels of HIV RNA are greater in children with poor growth compared with infected children with normal rates of growth. How HIV replication impedes growth has not been established but suppression of HIV appears to have a favorable effect on ponderal and linear growth. Further investigations are necessary to evaluate the potential role of anabolic agents for the management of HIV-associated growth failure.

Energy balance, viral burden, insulin-like growth factor-1, interleukin-6 and growth impairment in children infected with human immunodeficiency virus

OBJECTIVE

To determine the relationship between energy metabolism and growth abnormalities in HIV-infected children and to assess clinical or laboratory characteristics which may be contributing factors to their growth impairment.

DESIGN

A comparative study.

METHODS

We measured energy intake by inpatient calorie count/outpatient 24 h food recalls, resting energy expenditure by indirect calorimetry, total energy expenditure by the doubly-labeled water technique, iron metabolism, protein metabolism, and lipid metabolism markers as well as CD4 count, viral load, insulin-like growth factor-1 (IGF-1), serum interleukin-6 (IL-6), and whole blood stimulated IL-6 levels in prepubertal congenitally HIV-infected children with normal and impaired growth patterns.

RESULTS AND CONCLUSIONS

Differences in energy expenditures were not found between normal and growth-impaired HIV-infected children. Energy intake but not energy expenditure was significantly reduced when HIV-infected children were compared to expected normal values for age and gender. Advanced HIV clinical disease, severe immune suppression, increased viral burden, increased IL-6 activity, decreased total serum protein, and decreased IGF-1 levels were more likely to be found in HIV-infected children with growth impairment in comparison with HIV-infected children with normal growth.

Energetic adaptation to chronic disease in the elderly

Several chronic diseases occur with increased prevalence in the elderly. Body weight loss is a common feature of many chronic diseases. Weight loss increases the risk for morbidity and mortality and contributes to decreased functional independence and poor quality of life. Thus, an understanding of the effect of chronic disease on energy balance has important implications for nutritional supplementation and clinical outcome. This brief review will consider recent studies that have examined the effect of several chronic diseases (i.e., Alzheimer's disease, Parkinson's disease, and congestive heart failure) on daily energy expenditure in elderly individuals. Additionally, we put forth a model to explain the energetic adaptation to chronic disease in the elderly that is based on measurements of daily energy expenditure and its components. Studies suggest that chronic disease decreases daily energy expenditure in elderly individuals due to a marked reduction in physical activity energy expenditure. Moreover, these changes in daily energy expenditure often occur in the presence of increased resting energy expenditure. Thus, the net effect of chronic disease is to decrease daily energy expenditure. These results do not favor the hypothesis that increased energy expenditure contributes to disease-related weight loss. Instead, reduced energy intake appears to be a more likely mediator of the negative energy imbalance and weight loss that frequently accompany chronic disease in the elderly.