Exercise and weight loss in obese older adults with knee osteoarthritis: a preliminary study

OBJECTIVE: The purposes of this pilot study were to determine if a combined dietary and exercise intervention would result in significant weight loss in older obese adults with knee osteoarthritis, and to compare the effects of exercise plus dietary therapy with exercise alone on gait, strength, knee pain, biomarkers of cartilage degradation, and physical function. DESIGN: Single-blind, two-arm, randomized clinical trial conducted for 24 weeks. SETTING: A university health and exercise science center. PARTICIPANTS: Twenty-four community-dwelling obese older adults aged > or = 60 years, body mass index > or = 28, knee pain, radiographic evidence of knee osteoarthritis, and self-reported physical disability. INTERVENTION: Randomization into two groups: exercise and diet (E&D) and exercise alone (E). Exercise consisted of a combined weight training and walking program for 1 hour three times per week. The dietary intervention included weekly sessions with a nutritionist utilizing cognitive-behavior modification to change dietary habits to reach a group goal of an average weight loss of 15 lb (6.8 kg) over 6 months. MEASUREMENTS: All measurements were conducted at baseline and 3 and 6 months, except for synovial fluid analysis, which was obtained only at baseline and 6 months. In addition, weight was measured weekly in the E&D group. Physical disability and knee pain were measured by self-report and physical performance was measured using the 6-minute walk and stair climb tasks. Biomechanical testing included kinetic and kinematic analysis of gait and isokinetic strength testing. Synovial fluid was analyzed for levels of total proteoglycan, keratan sulfate, and interleukin-1 beta. RESULTS: Twenty-one of the 24 participants completed the study, with one dropout in the E&D group and two in the E group. The E&D group lost a mean of 18.8 lb (8.5 kg) at 6 months compared with 4.0 lb (1.8 kg) in the E group (P = .01). Significant improvements were noted in both groups in self-reported disability and knee pain intensity and frequency as well as in physical performance measures. However, no statistical differences were found between the two groups at 6 months in knee pain scores or self-reported performance measures of physical function. There was no difference in knee strength between the groups, with both groups showing modest improvements from baseline to 6 months. At 6 months, the E&D group had a significantly greater loading rate (P = .03) and maximum braking force (P = .01) during gait. There were no significant between-group differences in the other biomechanical measures. Synovial fluid samples were obtainable at both baseline and 6 months in eight participants (four per group). The level of keratan sulfate decreased similarly in both groups from an average baseline of 96.8 +/- 37.1 to 71.5 +/- 23 ng/microg total proteoglycan. The level of IL-1 decreased from 25.3 +/- 9.8 at baseline to 8.3 +/- 6.1 pg/mL. The decrease in IL-1 correlated with the change in pain frequency (r = -0.77, P = .043). CONCLUSIONS: Weight loss can be achieved and sustained over a 6-month period in a cohort of older obese persons with osteoarthritis of the knee through a dietary and exercise intervention. Both exercise and combined weight loss and exercise regimens lead to improvements in pain, disability, and performance. Moreover, the trends in the biomechanical data suggest that exercise combined with diet may have an additional benefit in improved gait compared with exercise alone. A larger study is indicated to determine if weight loss provides additional benefits to exercise alone in this patient population.     

Weight loss reduces knee-joint loads in overweight and obese older adults with knee osteoarthritis

OBJECTIVE: To determine the relationship between change in body mass and knee-joint moments and forces during walking in overweight and obese older adults with knee osteoarthritis (OA) following an 18-month clinical trial of diet and exercise. METHODS: Data were obtained from 142 sedentary, overweight, and obese older adults with self-reported disability and radiographic evidence of knee OA who underwent 3-dimensional gait analysis. Gait kinetic outcome variables included peak knee-joint forces and peak internal knee-joint moments. Mixed regression models were created to predict followup kinetic values, using followup body mass as the primary explanatory variable. Baseline body mass was used as a covariate, and thus followup body mass was a surrogate measure for change in body mass (i.e., weight loss). RESULTS: There was a significant direct association between followup body mass and peak followup values of compressive force (P = 0.001), resultant force (P = 0.002), abduction moment (P = 0.03), and medial rotation moment (P = 0.02). A weight reduction of 9.8 N (1 kg) was associated with reductions of 40.6 N and 38.7 N in compressive and resultant forces, respectively. Thus, each weight-loss unit was associated with an approximately 4-unit reduction in knee-joint forces. In addition, a reduction in body weight of 9.8 N (1 kg) was associated with a 1.4% reduction (0.496 Nm) in knee abduction moment. CONCLUSION: Our results indicate that each pound of weight lost will result in a 4-fold reduction in the load exerted on the knee per step during daily activities. Accumulated over thousands of steps per day, a reduction of this magnitude would appear to be clinically meaningful.     

Weight loss reduces knee‐joint loads in overweight and obese older adults with knee osteoarthritis

Objective

To determine the relationship between change in body mass and knee‐joint moments and forces during walking in overweight and obese older adults with knee osteoarthritis (OA) following an 18‐month clinical trial of diet and exercise.

Methods

Data were obtained from 142 sedentary, overweight, and obese older adults with self‐reported disability and radiographic evidence of knee OA who underwent 3‐dimensional gait analysis. Gait kinetic outcome variables included peak knee‐joint forces and peak internal knee‐joint moments. Mixed regression models were created to predict followup kinetic values, using followup body mass as the primary explanatory variable. Baseline body mass was used as a covariate, and thus followup body mass was a surrogate measure for change in body mass (i.e., weight loss).

Results

There was a significant direct association between followup body mass and peak followup values of compressive force (P = 0.001), resultant force (P = 0.002), abduction moment (P = 0.03), and medial rotation moment (P = 0.02). A weight reduction of 9.8N (1 kg) was associated with reductions of 40.6N and 38.7N in compressive and resultant forces, respectively. Thus, each weight‐loss unit was associated with an ∼4‐unit reduction in knee‐joint forces. In addition, a reduction in body weight of 9.8N (1 kg) was associated with a 1.4% reduction (0.496 Nm) in knee abduction moment.

Conclusion

Our results indicate that each pound of weight lost will result in a 4‐fold reduction in the load exerted on the knee per step during daily activities. Accumulated over thousands of steps per day, a reduction of this magnitude would appear to be clinically meaningful.

     

Exercise and dietary weight loss in overweight and obese older adults with knee osteoarthritis: the Arthritis, Diet, and Activity Promotion Trial

OBJECTIVE: The Arthritis, Diet, and Activity Promotion Trial (ADAPT) was a randomized, single-blind clinical trial lasting 18 months that was designed to determine whether long-term exercise and dietary weight loss are more effective, either separately or in combination, than usual care in improving physical function, pain, and mobility in older overweight and obese adults with knee osteoarthritis (OA). METHODS: Three hundred sixteen community-dwelling overweight and obese adults ages 60 years and older, with a body mass index of > or =28 kg/m(2), knee pain, radiographic evidence of knee OA, and self-reported physical disability, were randomized into healthy lifestyle (control), diet only, exercise only, and diet plus exercise groups. The primary outcome was self-reported physical function as measured with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes included weight loss, 6-minute walk distance, stair-climb time, WOMAC pain and stiffness scores, and joint space width. RESULTS: Of the 316 randomized participants, 252 (80%) completed the study. Adherence was as follows: for healthy lifestyle, 73%; for diet only, 72%; for exercise only, 60%; and for diet plus exercise, 64%. In the diet plus exercise group, significant improvements in self-reported physical function (P < 0.05), 6-minute walk distance (P < 0.05), stair-climb time (P < 0.05), and knee pain (P < 0.05) relative to the healthy lifestyle group were observed. In the exercise group, a significant improvement in the 6-minute walk distance (P < 0.05) was observed. The diet-only group was not significantly different from the healthy lifestyle group for any of the functional or mobility measures. The weight-loss groups lost significantly (P < 0.05) more body weight (for diet, 4.9%; for diet plus exercise, 5.7%) than did the healthy lifestyle group (1.2%). Finally, changes in joint space width were not different between the groups. CONCLUSION: The combination of modest weight loss plus moderate exercise provides better overall improvements in self-reported measures of function and pain and in performance measures of mobility in older overweight and obese adults with knee OA compared with either intervention alone.     

A decline in lower extremity lean body mass per body weight is characteristic of women with early phase osteoarthritis of the knee

OBJECTIVE: Sarcopenia progresses with aging, but the effect of muscle loss on degenerative joint disorders has not been precisely evaluated. We assessed the distribution of lean body mass (LBM) in middle aged women who had osteoarthritis (OA) of the knee for < 5 years. METHODS: Two hundred thirty-five Japanese women aged 45-69 years, including 117 with knee OA for < 5 years, and 118 age and sex matched healthy controls were studied. Body composition measurements were carried out by segmental bioelectrical impedance using 8 surface electrodes. Anthropometric data consisting of LBM of upper extremities/body weight (U-LBM/W), LBM of trunk/body weight (T-LBM/W), and LBM of lower extremities/body weight (L-LBM/W) for knee OA participants were compared to corresponding data for controls. In the knee OA group, the significance of correlations between anthropometric data and Lequesne index of severity for knee OA and between anthropometric data and disease duration were assessed. RESULTS: L-LBM/W was significantly lower in knee OA participants compared with controls (19.2 +/- 2.7% vs 21.0 +/- 2.9%; p < 0.0001). However, no significant differences in U-LBM/W and T-LBM/W were observed between the knee OA and control groups (p > 0.2). L-LBM/W did not correlate significantly with the index of severity or disease duration (p > 0.2). CONCLUSION: Decline in L-LBM/W, but not U-LBM/W or T-LBM/W, may be important in the pathogenesis of knee OA.     

Effect of weight loss and exercise on frailty in obese older adults

BACKGROUND: Obesity exacerbates the age-related decline in physical function and causes frailty in older persons. However, appropriate treatment for obese older persons is unknown. We evaluated the effects of weight loss and exercise therapy on physical function and body composition in obese older persons. METHODS: We screened 40 obese older volunteers and eventually randomized 27 frail obese older volunteers to treatment or control groups. Treatment consisted of 6 months of weekly behavioral therapy for weight loss in conjunction with exercise training 3 times per week. Physical function was evaluated with measurements of frailty (Physical Performance Test, peak oxygen consumption, and Functional Status Questionnaire); strength, gait, and balance tests; body composition with dual-energy x-ray absorptiometry; and quality of life using the Medical Outcomes Survey 36-Item Short-Form Health Survey. Results are reported as mean +/- SD. RESULTS: Two subjects in the treatment group did not comply with the intervention, and 1 subject in the control group withdrew. Analyses included all 27 subjects originally randomized to the treatment and control groups. The treatment group lost 8.4% +/- 5.6% of body weight, whereas weight did not change in the control group (+0.5% +/- 2.8%; P<.001). Compared with the control group, fat mass decreased (-6.6 +/- 3.4 vs +1.7 +/- 4.1 kg; P<.001), without a change in fat-free mass (-1.2 +/- 2.1 vs -1.0 +/- 3.5 kg; P = .75) in the treatment group. The Physical Performance Test score (2.6 +/- 2.5 vs 0.1 +/- 1.0; P = .001), peak oxygen consumption (1.7 +/- 1.6 vs 0.3 +/- 1.1 mL/min per kilogram; P = .02), and Functional Status Questionnaire score (2.9 +/- 3.7 vs -0.2 +/- 3.9; P = .02) improved in treated subjects compared with control subjects. Treatment also improved strength, walking speed, obstacle course, 1-leg limb stance time, and health survey physical subscale scores (all P<.05). CONCLUSION: These findings suggest that weight loss and exercise can ameliorate frailty in obese older adults.Trial Registration clinicaltrials.gov Identifier: NCT00146133.     

Exercise, self-efficacy, and mobility performance in overweight and obese older adults with knee osteoarthritis

OBJECTIVE: To examine changes in mobility-related self efficacy following exercise and dietary weight loss interventions in overweight and obese older adults with knee osteoarthritis (OA), and to determine if self efficacy and pain mediate the effects of the interventions on mobility task performance. METHODS: The Arthritis, Diet, and Activity Promotion Trial was an 18-month, single-blind, randomized, controlled trial comparing the effects of exercise alone, dietary weight loss alone, a combination of exercise plus dietary weight loss, and a healthy lifestyle control intervention in the treatment of 316 overweight or obese older adults with symptomatic knee OA. Participants completed measures of stair-climb time and 6-minute walk distance, self efficacy for completing each mobility task, and self-reported pain at baseline, 6 months, and 18 months during the trial. RESULTS: Mixed model analyses of covariance of baseline adjusted change in the outcomes demonstrated that the exercise + dietary weight loss intervention produced greater improvements in mobility-related self efficacy (P = 0.0035), stair climb (P = 0.0249) and 6-minute walk performance (P = 0.00031), and pain (P = 0.09) when compared with the healthy lifestyle control intervention. Mediation analyses revealed that self efficacy and pain served as partial mediators of the beneficial effect of exercise + dietary weight loss on stair-climb time. CONCLUSION: Exercise + dietary weight loss results in improved mobility-related self efficacy; changes in these task-specific control beliefs and self-reported pain serve as independent partial mediators of the beneficial effect of exercise + dietary weight loss on stair-climb performance.     

Muscle strength, mass, and quality in older men and women with knee osteoarthritis

Objective

To examine the relationship between knee osteoarthritis (OA) and muscle parameters in a biracial cohort of older adults.

Methods

Participants in the Health, Aging and Body Composition Study (n = 858) were included in this cross‐sectional analysis. Computed tomography was used to measure muscle area, and quadriceps strength was measured isokinetically. Muscle quality (specific torque) was defined as strength per unit of muscle area for both the entire thigh and quadriceps. Knee OA was assessed based on radiographic features and knee pain. We compared muscle parameters between those with and without radiographic knee OA (+RKOA group and ?RKOA group, respectively) and among 4 groups defined by +RKOA and ?RKOA with and without pain.

Results

The mean ± SD age was 73.5 ± 2.9 years and the mean ± SD body mass index (BMI) was 27.9 ± 4.8 kg/m². Fifty‐eight percent of participants were women and 44% were African American. Compared to the ?RKOA participants, +RKOA participants had a higher BMI (30.2 versus 26.8 kg/m²), larger thigh muscles (117.9 versus 108.9 cm²), and a greater amount of intermuscular fat (12.5 versus 9.9 cm²; all P < 0.0001). In adjusted models, the +RKOA participants had significantly lower specific torque (P < 0.001), indicating poorer muscle quality, than ?RKOA participants, but there was no difference between groups in quadriceps specific torque. The +RKOA without pain (P < 0.05) and the +RKOA with pain (P < 0.001) participants had lower specific torque compared to the ?RKOA without pain group. There were no significant differences in quadriceps specific torque among groups.

Conclusion

Muscle quality was significantly poorer in participants with RKOA regardless of pain status. Future studies should address how lifestyle interventions might affect muscle quality and progression of knee OA.

     

Self-efficacy mediates walking performance in older adults with knee osteoarthritis

BACKGROUND: Self-efficacy is a determinant of walking performance in older adults with knee osteoarthritis. We examined whether self-efficacy mediated the effect of age, psychosocial, impairment, and mechanical factors on walking performance. METHODS: Fifty-four participants with knee osteoarthritis completed the Six Minute Walk test and Arthritis Self-Efficacy Scale. Independent variables reflected age, psychosocial (depressive symptoms), impairment (pain, stiffness), and mechanical (strength, obesity) factors. RESULTS: Self-efficacy fully mediated the effect of age and impairments on walking. The effects of strength were only partially mediated by self-efficacy. Depressive symptoms and obesity were not mediated by self-efficacy. CONCLUSIONS: These findings are consistent with Social Cognitive Theory, according to which age may alter outcome expectations, and impairments like pain and stiffness provide negative physiological feedback to influence performance. Mechanical factors like strength and obesity may better represent a person's capabilities and interact with other variables to influence physical performance in older adults with knee osteoarthritis.     

Investigation of the association of weight loss with radiographic hip osteoarthritis in older community-dwelling female adults

Objective

Most guidelines recommending weight loss for hip osteoarthritis are based on research on knee osteoarthritis. Prior studies found no association between weight loss and hip osteoarthritis, but no previous studies have targeted older adults. Therefore, we aimed to determine whether there is any clear benefit of weight loss for radiographic hip osteoarthritis in older adults because weight loss is associated with health risks in older adults.

Methods

We used data from white female participants aged ≥65 years from the Study of Osteoporotic Fractures. Our exposure of interest was weight change from baseline to follow-up at 8 years. Our outcomes were the development of radiographic hip osteoarthritis (RHOA) and the progression of RHOA over 8 years. Generalized estimating equations (clustering of 2 hips per participant) were used to investigate the association between exposure and outcomes adjusted for major covariates.

Results

There was a total of 11,018 hips from 5509 participants. There was no associated benefit of weight loss for either of our outcomes. The odds ratios (95% confidence intervals) for the development and progression of RHOA were 0.99 (0.92–1.07) and 0.97 (0.86–1.09) for each 5% weight loss, respectively. The results were consistent in sensitivity analyses where participants were limited to those who reported trying to lose weight and who also had a body mass index in the overweight or obese range.

Conclusion

Our findings suggest no associated benefit of weight loss in older female adults in the structure of the hip joint as assessed by radiography.     

Growth hormone administration conserves lean body mass during dietary restriction in obese subjects

Because weight-reducing diets result in loss of lean body tissue as well as fat, we sought to determine whether injections of GH might facilitate the preservation of nitrogen and accelerate the loss of body fat during dietary restriction. The dietary intake of 8 obese subjects was restricted to 24 Cal/kg ideal BW and 1 g protein/kg for 11 weeks. During weeks 3-5, 4 subjects were given a total of 10 im injections of recombinant methionyl human GH, 1 morning injection every 48 h in a dosage of 0.1 mg/kg ideal BW. The other 4 subjects were given injections of vehicle. During weeks 8-10, the subjects who had received GH previously were given vehicle and vice versa. While receiving GH injections the mean daily nitrogen deficit [0.35 +/- 2.14 (+/- SD) g/day] was significantly less than the loss during injection of vehicle (2.21 +/- 1.45 g/day; P less than 0.001). Although three of six subjects lost 190% more fat (as determined by hydrostatic weighing) while receiving GH, the difference in group mean fat loss during GH injection was not significantly greater than that during injection of vehicle (3.06 +/- 1.39 kg lost with GH vs. 2.64 +/- 1.08 kg lost with vehicle; P = NS). In parallel with the changes in nitrogen balance, GH produced a significant increase in the mean plasma somatomedin-C/insulin-like growth factor I concentration. From a mean pretreatment value of 1.06 +/- 0.28 U/mL, a maximal value of 3.20 +/- 1.60 U/mL was achieved after 12 days of GH injection (P less than 0.001). Somatomedin-C/insulin-like growth factor I concentrations did not change during injection of vehicle. During GH injection weight loss was attenuated because of fluid retention. If weight loss was determined 1 week after the end of GH administration, however, the total weight loss (3.42 +/- 1.73 kg) was not significantly different from that during the 3 weeks of vehicle administration and the following week (4.16 +/- 1.30 kg). Fasting blood glucose and serum insulin concentrations did not change during GH administration, and no glycosuria was detected in morning urine samples. Short term GH administration is effective in decreasing the loss of lean body mass in individuals ingesting restricted diets. However, fat loss was not accelerated.     

Kidney function as a predictor of loss of lean mass in older adults: health, aging and body composition study

OBJECTIVES: To assess the association between kidney function and change in body composition in older individuals. DESIGN: Prospective cohort study. SETTING: Two sites, Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Three thousand twenty-six well-functioning, participants aged 70 to 79 in the Health, Aging and Body Composition Study. MEASUREMENTS: Body composition (bone-free lean mass and fat mass) was measured using dual x-ray absorptiometry annually for 4 years. Kidney function was measured at baseline according to serum creatinine (SCr). Comorbidity and inflammatory markers were evaluated as covariates in mixed-model, repeated-measures analysis. RESULTS: High SCr was associated with loss of lean mass in men but not women, with a stronger relationship in black men (P=.02 for difference between slopes for white and black men). In white men, after adjustment for age and comorbidity, higher SCr remained associated with loss of lean mass (-0.07+/-0.03 kg/y greater loss per 0.4 mg/dL (1 standard deviation (SD)), P=.009) but was attenuated after adjustment for inflammatory factors (-0.05+/-0.03 kg/y greater loss per SD, P=.10). In black men, the relationship between SCr and loss of lean mass (-0.19+/-0.04 kg/y per SD, P<.001) persisted after adjustment for inflammation and overall weight change. CONCLUSION: Impaired kidney function may contribute to loss of lean mass in older men. Inflammation appeared to mediate the relationship in white but not black men. Future studies should strive to elucidate mechanisms linking kidney disease and muscle loss and identify treatments to minimize loss of lean mass and its functional consequences.     

Knee joint stiffness during walking in knee osteoarthritis

Objective

To investigate the construct validity of walking knee stiffness as a measure to differentiate between individuals with and without knee osteoarthritis (OA) and the construct validity of walking knee stiffness as related to self‐reported knee stiffness. The contributors to walking stiffness and its relationship with loading rate and adduction moment are also investigated.

Methods

Thirty‐seven individuals with knee OA and 11 asymptomatic controls participated. Knee stiffness was calculated during walking as the change in knee flexion‐extension moment divided by the change in knee flexion angle. Forward‐stepwise regression models and Pearson's correlation coefficients were used to evaluate the relationships between variables.

Results

Knee stiffness in walking was significantly greater in the OA group (mean ± SD 10.1 ± 4.4 Nm/°/kg × 100) compared with the controls (mean ± SD 5.6 ± 1.5 Nm/°/kg × 100) (P < 0.001). Knee excursion range explained 39% of the variance in walking knee stiffness (B = ?0.736, P < 0.001) and knee extensor moment a further 7% (B = 6.974, P = 0.045). In the OA group, walking knee stiffness was not associated with self‐reported stiffness (r = 0.029; P = 0.863). For the OA group, greater self‐reported stiffness was associated with lower peak knee adduction moment (B = ?0.354, P < 0.001).

Conclusion

The construct validity of walking knee stiffness is supported. The poor correlation between walking stiffness and self‐reported stiffness suggests the 2 measures evaluate different aspects of knee stiffness. Since a measure of walking stiffness is likely to provide valuable information, future research evaluating its clinical significance is merited.

     

Adipose tissue distribution changes during rapid weight loss in obese adults.

Changes in adipose tissue distribution as defined by the waist-to-hip ratio (WHR), were evaluated in 16 android, obese subjects (seven male and nine female) given a very low energy ketogenic diet of 1.72 MJ (411 kcal) for 4 weeks. Total weight loss was significantly greater for the males (11.2 +/- 2.5 kg) compared to females (8.3 +/- 0.8 kg); the relative weight loss however, was similar (9.9 vs 9.3 percent). Female and male losses in percent body fat and lean body mass were not significantly different. For both groups, significant (P less than 0.01) changes in waist and hip circumferences were observed; however, no significant changes were observed in WHR. These results indicate that in obese android male and female subjects, adipose tissue distribution as measured by WHR, does not change in response to rapid weight loss.     

Short-term progressive resistance training increases strength and lean body mass in adults infected with human immunodeficiency virus

BACKGROUND: To assess the efficacy of progressive resistance training (PRT) in increasing strength and lean body mass (LBM) in HIV-infected adults. METHODS: Twenty-five adults with HIV infection were trained using a highly intensive PRT regimen for 8 weeks, followed by an additional 8 weeks of observation under ad libitum physical activity conditions. RESULTS: Twenty-four of the 25 patients completed the first phase of the study. They had significant increases in strength on all four exercises tested (P < 0.0001), and an increase in LBM of 1.75 +/- 1.94 kg (mean +/- SD, P < 0.0002), with a concomitant decline in fat of 0.92 +/- 2.22 kg (P < 0.05), and no significant change in weight or bone mineral content. Twenty-one of the patients returned for follow-up 8 weeks after completing the PRT. Compared with their baseline values, their mean lean mass remained 1.40 +/- 1.8 kg higher (P < 0.003). Among those who continued to train to some extent, lean mass increased by a mean of 1.1 +/- 1.6 kg (n = 9, P < 0.05 versus end of PRT), whereas those who did no further training showed an increase in lean mass of 0.28 +/- 1.4 kg (n = 12, P = NS versus end of PRT). The difference between the two groups was not, however, significant (P = 0.25). Among six patients with AIDS wasting, the increase in LBM was larger than among non-wasted patients (2.8 versus 1.4 kg, P < 0.06), and there was an increase in both weight (+3.9 versus -0.2 kg, P < 0.002) and fat mass (+ 0.95 versus -1.5 kg, P < 0.002) at 8 weeks, which persisted at 16 weeks (weight: +4.0 versus -1.6 kg, P < 0.0002; fat: +1.6 versus -1.9 kg, P < 0.01). CONCLUSION: This preliminary study suggests that short-term, high intensity PRT can significantly increase LBM and strength in HIV infection, and may be used as an alternative or adjunct to pharmacological anabolic treatments in this disease.     

Body mass index, weight loss, and mortality in community-dwelling older adults

BACKGROUND: The relationship between body mass index (BMI), weight loss, and mortality in older adults is not entirely clear. The purpose of this article is to evaluate the associations between BMI, weight loss (either intentional or unintentional), and 3-year mortality in a cohort of older adults participating in the University of Alabama at Birmingham (UAB) Study of Aging. METHODS: This article reports on 983 community-dwelling older adults who were enrolled in the UAB Study of Aging, a longitudinal observational study of mobility among older African American and white adults. RESULTS: In both raw and adjusted Cox proportional hazards models, unintentional weight loss and underweight BMI were associated with elevated 3-year mortality rates. There was no association with being overweight or obese on mortality, nor was there an association with intentional weight loss and mortality. CONCLUSIONS: Our study suggests that undernutrition, as measured by low BMI and unintentional weight loss, is a greater mortality threat to older adults than is obesity or intentional weight loss.