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Background: The purpose of this study was to examine whether select baseline characteristics influenced the likelihood of an overweight/obese, older adult experiencing a clinically meaningful gait speed response (±0.05 m/s) to caloric restriction (CR).Methods: Individual level data from 1 188 older adults participating in 8, 5/6-month, weight loss interventions were pooled, with treatment arms collapsed into CR (n = 667) or no CR (NoCR; n = 521) categories. Exercise assignment was equally distributed across groups (CR: 65.3% vs NoCR: 65.4%) and did not interact with CR (p = .88). Poisson risk ratios (95% confidence interval [CI]) were used to examine whether CR assignment interacted with select baseline characteristic subgroups: age (≥65 years), sex (female/male), race (Black/White), body mass index (BMI; ≥35 kg/m2), comorbidity (diabetes, hypertension, cardiovascular disease) status (yes/no), gait speed (<1.0 m/s), or inflammatory burden (C-reactive protein ≥3 mg/L, interleukin-6 ≥2.5 pg/mL) to influence achievement of ±0.05 m/s fast-paced gait speed change. Main effects were also examined.Results: The study sample (69.5% female, 80.1% White) was 67.6 ± 5.3 years old with a BMI of 33.8 ± 4.4 kg/m2. Average weight loss achieved in the CR versus NoCR group was -8.3 ± 5.9% versus -1.1 ± 3.8%; p < .01. No main effect of CR was observed on the likelihood of achieving a clinically meaningful gait speed improvement (risk ratio [RR]: 1.09 [95% CI: 0.93, 1.27]) or gait speed decrement (RR: 0.77 [95% CI: 0.57, 1.04]). Interaction effects were nonsignificant across all subgroups.Conclusion: The proportion of individuals experiencing a clinically meaningful gait speed change was similar for CR and NoCR conditions. This finding is consistent across several baseline subgroupings. [ABSTRACT FROM AUTHOR]

Background. The effects of weight loss on muscle function in older adults have not been well studied. This study determined the effects of a 6-month weight-loss intervention on muscle strength and quality in older obese adults with knee osteoarthritis. Methods. Participants were randomized to a weight loss (WL) (n =44, 70 [+ or -] 6 years) or weight stable (WS) (11=43, 69 [+ or -] 6 years) group. The WL intervention consisted of weekly educational meetings, a meal replacement diet, and a three-session-per-week structured exercise program to achieve 10%-12% weight loss. The WS intervention included bimonthly group meetings and newsletters. Body composition and knee extensor strength were measured at baseline and after intervention. Results. The WL group decreased body weight, lean body mass, fat mass, and percent body fat (p < .001 for all). Concentric extension strength increased 25% in WL (p > .05), whereas eccentric extension decreased 6% in WS (p = .028). Concentric muscle quality (strength per kg body weight or lean body mass) increased in WL (p < .05), whereas eccentric muscle quality decreased in WS (p < .05). Changes in lean body mass and fat mass were inversely associated with changes in most muscle strength and quality measures (p < .05). Men and women did not differ in response to the intervention in knee strength outcomes. Conclusions. Hypocaloric dieting in combination with exercise training had beneficial effects on muscle strength/quality, despite loss of lean body mass in this sample of older men and women. Greater fat loss was associated with greater gains in muscle strength and quality. More studies are needed regarding the mechanisms by which loss of fat mass increases muscle strength and quality.

Background. We determined whether physical function and its response to exercise training are associated with polymorphisms in cytokine genes (interleukin-6 [IL-6] -174 G/C; tumor necrosis factor alpha [TNF[alpha]] -308 G/A and -238 G/A; and TNF[alpha] receptors [TNFR]1 +36 A/G, TNFR2 +676 T/G, and TNFR2-1663 A/G), in 214 older ([greater than or equal to] 60 years), overweight (body mass index [greater than or equal to] 28 kg/[m.sup.2]) individuals with knee osteoarthritis. Methods. Physical function (walking distance, stair-climb time, self-reported disability) was measured before and after an 18-month randomized, controlled exercise trial involving walking and weight lifting 3 days/week. Results. In cross-sectional analyses, baseline walking distance was greater in individuals homozygous for the major G allele at IL-6 -174 compared to individuals with at least one C allele (p = .05). Both walking distance (p = .02) and stair-climb time (p = .003) were better in individuals homozygous for the major G allele of the TNF[alpha] -308 polymorphism compared to those with at least one A allele. Walking distance was better (p = .02), and stair-climb time tended to be better (p = .06), in individuals homozygous for the major T allele of the TNFR2 +676 polymorpbism. No associations were seen with self-reported physical disability nor with the other polymorphisms. In response to exercise, there was a significant interaction between TNF[alpha]-308 genotype and exercise treatment on 6-month changes in stair-climb time (p.007), and on 18-month changes in self-reported physical disability (p = .01), such that individuals with an A allele showed greater improvement in response to exercise. Conclusions. Walking distance and stair climbing speed are partly influenced by genetic variation in the IL-6 and TNF[alpha] genes in older individuals with knee osteoarthritis.

Regular exercise involving aerobic activities or resistance exercises appears to improve functioning in elderly people with osteoarthritis of the knee. Researchers randomly assigned 365 people 60 years old or older to 18 months of aerobic exercise, resistance exercise or a health education program. The aerobic and resistance exercises consisted of a 1-hour session 3 times a week that included a warm-up and cool-down period. The health education program consisted of videos and pamphlets on arthritis. Compared to those in the health education group, those in the exercise groups had significantly less disability at the end of the study., Objective. -- To determine the effects of structured exercise programs on self-reported disability in older adults with knee osteoarthritis. Setting and Design. -- A randomized, single-blind clinical trial lasting 18 months conducted at 2 academic medical centers. Participants. -- A total of 439 community-dwelling adults, aged 60 years or older, with radiographically evident knee osteoarthritis, pain, and self-reported physical disability. Interventions: -- An aerobic exercise program, a resistance exercise program, and a health education program. Main Outcome Measures. -- The primary outcome was self-reported disability score (range, 1-5). The secondary outcomes were knee pain score (range, 1-6), performance measures of physical function, x-ray score, aerobic capacity, and knee muscle strength. Results. -- A total of 365 (83%) participants completed the trial. Overall compliance with the exercise prescription was 68% in the aerobic training group and 70% in the resistance training group. Postrandomization, participants in the aerobic exercise group had a 10% lower adjusted mean ([+ or -]SE) score on the physical disability questionnaire (1.71 [+ or -]0.03 vs 1.90 [+ or -] 0.04 units; P [is less than].001), a 12% lower score on the knee pain questionnaire (2.1 [+ or -]0.05 vs 2.4 [+ or -] 0.05 units; P=.001), and performed better (mean [[+ or -] SE]) on the 6-minute walk test (1507 + or -] 16 vs 1349 [+ or -] 16 ft; P [is less than] .001), mean ([+ or -] SE) time to climb and descend stairs (12.7 [+ or -] 0.4 vs 13.9 [+ or -] 0.4 seconds; P=.05), time to lift and carry 10 pounds (9.1 [+ or -] 0.2 vs 10.0 [+ or -] 0.1 seconds; P [is less than] .001), and mean ([+ or -] SE) time to get in and out of a car (8.7 [+ or -] 0.3 vs 10.6 [+ or -] 0.3 seconds; P [is less than] .001) than the health education group. The resistance exercise group had an 8% lower score on the physical disability questionnaire (1.74 [+ or -] 0.04 vs 1.90 [+ or -] 0.03 units; P=.003), 81% lower pain score (2.2 [+ or -] 0.06 vs 2.4 [+ or -] 0.05 units; P=.02), greater distance on the 6-minute walk (1406 [+ or -] 17 vs 1349 [+ or -] 16 ft; P=.02), faster times on the lifting and carrying task (9.3 [+ or -] 0.1 vs 10.0 [+ or -] 0.16 seconds; P=.001), and the car task (9.0 [+ or -] 0.3 vs 10.6 [+ or -] 0.3 seconds; P=.003) than the health education group. There were no differences in x-ray scores between either exercise group and the health education group. Conclusions. -- Older disabled persons with osteoarthritis of the knee had modest improvements in measures of disability, physical performance, and pain from participating in either an aerobic or a resistance exercise program. These data suggest that exercise should be prescribed as part of the treatment for knee osteoarthritis.

Abstract Background Obesity is the most modifiable risk factor, and dietary induced weight loss potentially the best nonpharmacologic intervention to prevent or to slow osteoarthritis (OA) disease progression. We are currently conducting a study to test the hypothesis that intensive weight loss will reduce inflammation and joint loads sufficiently to alter disease progression, either with or without exercise. This article describes the intervention, the empirical evidence to support it, and test-retest reliability data. Methods/Design This is a prospective, single-blind, randomized controlled trial. The study population consists of 450 overweight and obese (BMI = 27–40.5 kg/m2) older (age ≥ 55 yrs) adults with tibiofemoral osteoarthritis. Participants are randomized to one of three 18-month interventions: intensive dietary restriction-plus-exercise; exercise-only; or intensive dietary restriction-only. The primary aims are to compare the effects of these interventions on inflammatory biomarkers and knee joint loads. Secondary aims will examine the effects of these interventions on function, pain, and mobility; the dose response to weight loss on disease progression; if inflammatory biomarkers and knee joint loads are mediators of the interventions; and the association between quadriceps strength and disease progression. Results Test-retest reliability results indicated that the ICCs for knee joint load variables were excellent, ranging from 0.86 – 0.98. Knee flexion/extension moments were most affected by BMI, with lower reliability with the highest tertile of BMI. The reliability of the semi-quantitative scoring of the knee joint using MRI exceeded previously reported results, ranging from a low of 0.66 for synovitis to a high of 0.99 for bone marrow lesion size. Discussion The IDEA trial has the potential to enhance our understanding of the OA disease process, refine weight loss and exercise recommendations in this prevalent disease, and reduce the burden of disability. Trial Registration NCT00381290