The Association of Total Knee Arthroplasty With Weight Loss in the Look AHEAD (Action for Health in Diabetes) Clinical Trial.

BACKGROUND: Patients who have obesity seldom lose weight after total knee arthroplasty (TKA). The Look AHEAD (Action for Health in Diabetes) trial randomized patients with type 2 diabetes who were overweight or had obesity to a 10-year intensive lifestyle intervention (ILI) or diabetes support and education (DSE). METHODS: Of the total 5,145 participants enrolled who had a median 14-year follow-up, a subset of 4,624 met inclusion criteria. The ILI aimed at achieving and maintaining a 7% weight loss and included weekly counseling the first 6 months, with decreasing frequency thereafter. This secondary analysis was undertaken to determine what effects a TKA had on patients participating in a known successful weight loss program and specifically if there was a negative impact on weight loss or their Physical Component Score. RESULTS: The analysis suggests that the ILI remained effective for maintaining or losing weight after TKA. Participants in ILI had significantly greater percent weight loss than those in DSE both before and after TKA (ILI-DSE before TKA: -3.6% (-5.0, -2.3); after TKA: -3.7% (-4.1, -3.3); both P < .0001). When comparing percent weight loss before to after TKA, there was no significant difference within either the DSE or ILI group (least square means ± standard error ILI: -0.36% ± 0.3, P = .21; DSE: -0.41% ± 0.29, P = .16). Physical Component Scores improved after TKA (P < .001), but no difference was found between TKA ILI and DSE groups before or after surgery. CONCLUSION: Participants who had a TKA did not have an altered ability to adhere to intervention goals to maintain weight loss or obtain further weight loss. The data suggest patients who have obesity can lose weight after TKA on a weight loss program.

Legacy of a 10-Year Multidomain Lifestyle Intervention on the Cognitive Trajectories of Individuals with Overweight/Obesity and Type 2 Diabetes Mellitus.

INTRODUCTION: Weight loss and increased physical activity interventions are commonly recommended for individuals with type 2 diabetes (T2D) and overweight or obesity. We examined the impact of randomization to an intensive lifestyle intervention (ILI) on trajectories of cognitive function over 10 years in a cohort of participants in a randomized clinical trial who had T2D and overweight/obesity at baseline. METHODS: Participants aged 45-76 years were enrolled in 2001-2004 and were randomized to the ILI or a diabetes support and education (DSE) condition. Cognitive function was assessed in 3,938 participants at up to 4 time points 8-18 years after randomization. General linear mixed effects models examined cognitive trajectories over time. Subgroup analyses focused on sex, individuals with baseline body mass index >30, those carrying the APOE ε4 allele, and those with a baseline history of cardiovascular disease (CVD). RESULTS: Overall, there were no differences in the rate of cognitive decline by intervention arm. Subgroup analyses showed that participants who had a baseline history of CVD and were randomized to the ILI arm of the study performed significantly worse on the Stroop Color Word Test than those in the DSE arm. DISCUSSION/CONCLUSIONS: The ILI did not result in preserved cognitive function or slower rates of cognitive decline in this cohort of individuals who had T2D and were overweight or obese at baseline.

Association of the Intensive Lifestyle Intervention With Total Knee Replacement in the Look AHEAD (Action for Health in Diabetes) Clinical Trial.

BACKGROUND: Evidence has established obesity as a risk factor for total knee replacement (TKR) due to osteoarthritis. Obesity is a risk factor for TKR. Randomized trials such as Look AHEAD (Action for Health in Diabetes) have shown long-term successful weight loss with an intensive lifestyle intervention (ILI). It is unknown, however, if intentional weight loss can reduce the risk of TKR. METHODS: Look AHEAD randomized persons aged 45-76 with type 2 diabetes who had overweight or obesity to either an ILI to achieve/maintain 7% weight loss or to standard diabetes support and education (DSE). Reported knee pain was assessed using the Visual Analog Scale and Western Ontario McMaster University Osteoarthritis Index questionnaire in 5125 participants without previous TKR. Cox proportional hazard regression was used to model differences in risk of TKR in relation to randomization group assignment (ILI vs DSE) along with baseline body mass index category and baseline knee pain as potential confounders from baseline through Look AHEAD-Extension. RESULTS: Baseline mean ± SD Western Ontario McMaster University Osteoarthritis Index knee pain scores did not differ by treatment assignment (ILI: 3.6 ± 2.9, DSE: 3.9 ± 3.0, P = .08); as expected due to randomization. During follow up, the 631 (12%) participants who reported having a TKR were more likely to have been heavier (P < .001) and older (P < .001) at enrollment, but risk of TKR did not differ by treatment group assignment (hazard ratio [HR] 1.07, 95% confidence interval [CI] 0.91-1.25, P = .43). Heterogeneity of treatment effect was observed according to baseline knee pain (interaction P = .02). In persons without knee pain at baseline, there was a 29% reduced risk of TKR in ILI compared to DSE (HR 0.71, 95% CI 0.52-0.96). However, in persons with knee pain at baseline, there was no statistically significant association of treatment assignment with respect to subsequent TKR incidence (HR 1.11, 95% CI 0.92-1.33). CONCLUSION: Findings suggest that intensive lifestyle change including physical activity, dietary restriction and behavioral changes to achieve weight loss for prevention of TKR may be most effective in preventing TKR prior to the development of knee pain.

Dietary outcomes within the study of novel approaches to weight gain prevention (SNAP) randomized controlled trial.

BACKGROUND: Young adults (YA) are at high-risk for unhealthy dietary behaviors and weight gain. The Study of Novel Approaches to Weight Gain Prevention (SNAP) Trial demonstrated that two self-regulation approaches were effective in reducing weight gain over 2 years compared with control. The goal of this analysis was to examine effects of intervention on dietary outcomes and the association of diet changes with weight change. METHODS: Participants were 599 YA, age 18-35 years, BMI 21.0-30.0 kg/m2 (27.4 ± 4.4 years; 25.4 ± 2.6 kg/m2; 22% men; 73% non-Hispanic White), who were recruited in Providence, RI and Chapel Hill, NC and randomized to self-regulation with Small Changes (SC), self-regulation with Large Changes (LC) or Control (C). SC and LC emphasized frequent self-weighing to cue behavior changes (small daily changes vs. periodic large changes) and targeted high-risk dietary behaviors. Diet and weight were assessed at baseline, 4 months and 2 years. RESULTS: LC and SC had greater decreases in energy intake than C at 4 months but not 2 years. LC had the greatest changes in percent calories from fat at 4 months, but differences were attenuated at 2 years. No differences in diet quality were observed. Across conditions, increased total energy consumption, fast food, meals away from home, and binge drinking, and decreased dietary quality and breakfast consumption were all associated with weight gain at 2 years. CONCLUSIONS: This study suggests the need to strengthen interventions to produce longer term changes in dietary intake and helps to identify specific behaviors associated with weight gain over time in young adults. TRIAL REGISTRATION: Clinicaltrials.gov # NCT01183689 , registered August 18, 2010.

Sex-related differences in the prevalence of cognitive impairment among overweight and obese adults with type 2 diabetes.

INTRODUCTION: Type 2 diabetes mellitus and obesity may increase risks for cognitive decline as individuals age. It is unknown whether this results in different prevalences of cognitive impairment for women and men. METHODS: The Action for Health in Diabetes, a randomized controlled clinical trial of a 10-year intensive lifestyle intervention, adjudicated cases of cross-sectional cognitive impairment (mild cognitive impairment or dementia) 10-13 years after enrollment in 3802 individuals (61% women). RESULTS: The cross-sectional prevalences of cognitive impairment were 8.3% (women) and 14.8% (men): adjusted odds ratio 0.55, 95% confidence interval [0.43, 0.71], P < .001. Demographic, clinical, and lifestyle risk factors varied between women and men but did not account for this difference, which was limited to individuals without apolipoprotein E (APOE)-ε4 alleles (interaction P = .034). CONCLUSIONS: Among overweight and obese adults with type 2 diabetes mellitus, traditional risk factors did not account for the lower prevalence of cognitive impairment observed in women compared with men.

Self-Reported Gastrointestinal Symptoms in Type 2 Diabetes Improve With an Intensive Lifestyle Intervention: Results From the Action for Health in Diabetes (Look AHEAD) Clinical Trial.

In Brief This article reports on an investigation of whether an intensive lifestyle intervention (ILI) would reduce gastrointestinal symptoms over 4 years of follow-up for participants in the Action for Health in Diabetes (Look AHEAD) trial compared to a diabetes support and education (DSE) group. Look AHEAD is a randomized, multicenter trial comparing overweight and obese adults with type 2 diabetes treated with ILI versus DSE. ILI, and weight loss in general, had beneficial effects on gastrointestinal (GI) symptoms, with some variability in the strength of the effect depending on the specific symptom and time course. Potential modifiers were analyzed, yet ILI retained an association with improvement in GI symptoms.

Glove and gown effects on intraoperative bacterial contamination.

OBJECTIVE: Experiments were performed to determine the risk of bacterial contamination associated with changing outer gloves and using disposable spunlace paper versus reusable cloth gowns. BACKGROUND: Despite decades of research, there remains a lack of consensus regarding certain aspects of optimal aseptic technique including outer glove exchange while double-gloving and surgical gown type selection. METHODS: In an initial glove study, 102 surgical team members were randomized to exchange or retain outer gloves 1 hour into clean orthopedic procedures; cultures were obtained 15 minutes later from the palm of the surgeon's dominant gloved hand and from the surgical gown sleeve. Surgical gown type selection was recorded. A laboratory strike-through study investigating bacterial transmission through cloth and paper gowns was performed with coagulase-negative staphylococci. In a follow-up glove study, 251 surgical team members, all wearing paper gowns, were randomized as in the first glove study. RESULTS: Glove study 1 revealed 4-fold higher levels of baseline bacterial contamination (31% vs 7%) on the sleeve of surgical team members wearing cloth gowns than those using paper gowns [odds ratio (95% confidence interval): 4.64 (1.72-12.53); P = 0.0016]. The bacterial strike-through study revealed that 26 of 27 cloth gowns allowed bacterial transmission through the material compared with 0 of 27 paper gowns (P < 0.001). In glove study 2, surgeons retaining outer gloves 1 hour into the case had a subsequent positive glove contamination rate of 23% compared with 13% among surgeons exchanging their original outer glove [odds ratio (95% confidence interval): 1.97 (1.02-3.80); P = 0.0419]. CONCLUSIONS: Paper gowns demonstrated less bacterial transmission in the laboratory and lower rates of contamination in the operating room. Disposable paper gowns are recommended for all surgical cases, especially those involving implants, because of the heightened risk of infection. Outer glove exchange just before handling implant materials is also recommended to minimize intraoperative contamination.

Breath alcohol estimation training: behavioral effects and predictors of success.

AIMS: Breath alcohol concentration (BrAC) estimation training has been effective in increasing estimation accuracy in social drinkers. Predictors of estimation accuracy may identify populations to target for training, yet potential predictors typically are not evaluated. In addition, the therapeutic efficacy of estimation training as a preventive strategy for problematic drinking is unknown. METHODS: Forty-six social drinkers with a recent binge history were randomly assigned to an intervention or control group (n = 23 per group). In each of three sessions (pretraining, training, testing), participants consumed alcohol (0.32, 0.24, 0.16 and 0.08 g/kg, in random order) every 30 min (total dose: 0.8 g/kg). Participants provided five BrAC estimates within 3 h of alcohol administration. The intervention group, but not control group, received internal and external training. During testing, participants provided BrAC estimates, but received no feedback. Participants returned for two follow-up visits to complete self-report measures. RESULTS: BrAC estimation training improved intervention group estimation accuracy within the laboratory. Together, training, low trait anxiety and low risk expectancy predicted high testing accuracy. There were no significant group differences in subsequent alcohol consumption, behavior under the influence or risk expectancy regarding potentially hazardous behaviors. CONCLUSION: BrAC estimation training is effective in the laboratory but may not translate into naturalistic settings.

Factors associated with falls in older adults: A secondary analysis of a 12-month randomized controlled trial.

PURPOSE: While identifying older adults at risk for falls is important, fall prediction models have had limited success, in part because of a poor understanding of which physical function measures to include. The purpose of this secondary analysis was to determine physical function measures that are associated with future falls in older adults. METHODS: In a 12-month trial comparing Vitamin D3 supplementation versus placebo on neuromuscular function, 124 older adults completed physical function measures at baseline, including the Short Physical Performance Battery (SPPB), Timed Up and Go, tests of leg strength and power, standing balance on a force plate with firm and foam surfaces, and walking over an instrumented walkway. Falls were recorded with monthly diaries over 12 months and categorized as no falls vs. one or more falls. Univariate and multivariable logistic regression adjusting for demographics, treatment assignment, depression, and prescription medications were conducted to examine the association between each physical function measure and future falls. Models were additionally adjusted for fall history. RESULTS: 61 participants sustained one or more falls. In univariate analysis, white race, depression, fall history, SPPB, and postural stability on foam were significantly associated with future falls. In multivariable analysis, fall history (OR (95% CI): 3.20 (1.42-7.43)), SPPB (0.80 (0.62-1.01)), and postural stability on foam (3.01 (1.18, 8.45)) were each significantly associated with future falls. After adjusting for fall history, only postural stability on foam was significantly associated with falls. CONCLUSIONS: When developing fall prediction models, fall history, the SPPB, and postural stability when standing on foam should be considered.

Vitamin D Supplementation and Muscle Power, Strength and Physical Performance in Older Adults: A Randomized Controlled Trial.

BACKGROUND: Low 25-hydroxyvitamin D (25[OH]D) concentrations (<30 ng/mL [<50 nmol/L]) have been associated with muscle weakness and impaired physical performance in observational studies. However, the effect of vitamin D supplementation on changes in muscle strength and physical performance in randomized controlled trials has been mixed. OBJECTIVES: To determine the effect of daily vitamin D supplementation on leg power, strength, and physical performance in low-functioning older adults with 25(OH)D concentrations of 18 to <30 ng/mL. METHODS: In this double-blind, randomized controlled trial, 136 low-functioning [Short Physical Performance Battery (SPPB) scores ≤10] adults aged 65-89 y with 25(OH)D concentrations of 18 to <30 ng/mL were randomly assigned to 2000 IU/d vitamin D3 or placebo for 12 mo. Lower-extremity leg power (primary outcome), leg and grip strength, SPPB, timed up and go (TUG), postural sway, and gait velocity and spatiotemporal parameters (secondary outcomes) were assessed at baseline, 4 and 12 mo. A subset (n = 37) also underwent a muscle biopsy at baseline and 4 mo and muscle fiber composition and contractile properties were assessed. RESULTS: Participants' mean ± SD age and SPPB scores at baseline were 73.4 ± 6.3 y and 7.8 ± 1.8, respectively. Mean ± SD 25(OH)D concentrations at baseline and 12 mo were 19.4 ± 4.2 ng/mL and 28.6 ± 6.7 ng/mL in the vitamin D group and 19.9 ± 4.9 ng/mL and 20.2 ± 5.0 ng/mL in the placebo group for a mean ± SE difference of 9.1 ± 1.1 ng/mL (P < 0.0001). However, there were no differences in change in leg power, leg or grip strength, SPPB score, TUG, postural sway, or gait velocity and spatiotemporal parameters by intervention group over 12 mo or muscle fiber composition and contractile properties over 4 mo. CONCLUSIONS: In low-functioning older adults with 25(OH)D concentrations of 18 to <30 ng/mL, randomization to 2000 IU/d vitamin D3 did not result in improvements in leg power, strength, or physical performance or muscle fiber composition and contractile properties. This trial was registered at clinicaltrials.gov as NCT02015611.

Rationale, design, and cohort characteristics of the Action for Health in Diabetes Aging study.

INTRODUCTION: Diabetes and overweight/obesity are described as accelerating aging processes, yet many individuals with these conditions maintain high levels of cognitive and physical function and independence late into life. The Look AHEAD Aging study is designed to identify 20-year trajectories of behaviors, risk factors, and medical history associated with resilience against geriatric syndromes and aging-related cognitive and physical functional deficits among individuals with these conditions. METHODS: Look AHEAD Aging extends follow-up of the cohort of the former 10-year Look AHEAD trial. The original cohort (N = 5145) was enrolled in 2001 to 2004 when participants were aged 45 to 76 years and randomly assigned to a multidomain intensive lifestyle intervention (ILI) or a diabetes support and education (DSE) condition. The trial interventions ceased in 2012. Clinic-based follow-up continued through 2020. In 2021, the cohort was invited to enroll in Look AHEAD Aging, an additional 4-year telephone-based follow-up (every 6 months) enhanced with Medicare linkage. Standardized protocols assess multimorbidity, physical and cognitive function, health care utilization, and health-related quality of life. RESULTS: Of the original N = 5145 Look AHEAD participants, N = 1552 active survivors agreed to participate in Look AHEAD Aging. At consent, the cohort's mean age was 76 (range 63 to 94) years and participants had been followed for a mean of 20 years. Of the original Look AHEAD enrollees, those who were younger, female, or with no history of cardiovascular disease were more likely to be represented in the Look AHEAD Aging cohort. Intervention groups were comparable with respect to age, diabetes duration, body mass index, insulin use, hypertension, cardiovascular disease, and cognitive function. ILI participants had significantly lower deficit accumulation index scores. DISCUSSION: By continuing the long-term follow-up of an extensively characterized cohort of older individuals with type 2 diabetes, Look AHEAD Aging is well positioned to identify factors associated with resilience against aging-related conditions.

25-hydroxyvitamin D status and change in physical performance and strength in older adults: the Health, Aging, and Body Composition Study.

Low 25-hydroxyvitamin D (25(OH)D) concentrations are common among older adults and are associated with poorer physical performance and strength, but results from longitudinal studies have been inconsistent. The 25(OH)D threshold for physical performance and strength was determined, and both cross-sectional and longitudinal associations between 25(OH)D and physical performance and strength were examined, in men and women aged 71-80 years from the Health, Aging, and Body Composition Study (n = 2,641). Baseline serum 25(OH)D was measured in 1998-1999, and physical performance and strength were measured at baseline and at 2- and 4-year follow-up. Piecewise regression models were used to determine 25(OH)D thresholds. Linear regression and mixed models were used to examine cross-sectional and longitudinal associations. The 25(OH)D thresholds were 70-80 nmol/L for physical performance and 55-70 nmol/L for strength. Participants with 25(OH)D <50 nmol/L had poorer physical performance at baseline and at 2- and 4-year follow-up than participants with 25(OH)D ≥75 nmol/L (P < 0.01). Although physical performance and strength declined over 4 years of follow-up (P < 0.0001), in general, the rate of decline was not associated with baseline 25(OH)D. Older adults with low 25(OH)D concentrations had poorer physical performance over 4 years of follow-up, but low 25(OH)D concentrations were not associated with a faster rate of decline in physical performance or strength.

The relationship between cognitive function and non-prescribed therapy use in older adults.

OBJECTIVES: To examine the association of cognitive function with use of non-prescribed therapies for managing acute and chronic conditions, and to determine whether use of non-prescribed therapies changes over time in relation to baseline cognitive function. METHODS: 200 community-dwelling adults aged 65 and older were recruited from three counties in south central North Carolina. Repeated measures of daily symptoms and treatment were collected on three consecutive days at intervals of at least one month. The Mini-Mental State Examination, the primary cognitive measure, was collected as part of the baseline survey. Data were collected on the daily use of common non-prescribed therapies (use of prayer, ignore symptoms, over-the-counter remedies, food and beverage therapies, home remedies, and vitamin, herb, or supplements) on each of the three days of the follow-up interviews for up to six consecutive months. RESULTS: Older adults with poorer cognitive function were more likely to pray and ignore symptoms on days that they experienced acute symptoms. Poorer cognitive function was associated with increased use of home remedies for treating symptoms related to existing chronic conditions. CONCLUSIONS: Cognitive function may play a role in why older patients use some non-prescribed therapies in response to acute and chronic conditions.

Effect of a stepped-care intervention approach on weight loss in adults: a randomized clinical trial.

CONTEXT: Given the obesity epidemic, effective but resource-efficient weight loss treatments are needed. Stepped-treatment approaches customize interventions based on milestone completion and can be more effective while costing less to administer than conventional treatment approaches. OBJECTIVE: To determine whether a stepped-care weight loss intervention (STEP) compared with a standard behavioral weight loss intervention (SBWI) would result in greater weight loss. DESIGN, SETTING, AND PARTICIPANTS: A randomized clinical trial of 363 overweight and obese adults (body mass index: 25-<40; age: 18-55 years, 33% nonwhite, and 83% female) who were randomized to SBWI (n = 165) or STEP (n = 198) at 2 universities affiliated with academic medical centers in the United States (Step-Up Study). Participants were enrolled between May 2008 and February 2010 and data collection was completed by September 2011. INTERVENTIONS: All participants were placed on a low-calorie diet, prescribed increases in physical activity, and attended group counseling sessions ranging from weekly to monthly during an 18-month period. The SBWI group was assigned to a fixed program. Counseling frequency, type, and weight loss strategies could be modified every 3 months for the STEP group in response to observed weight loss as it related to weight loss goals. MAIN OUTCOME MEASURE: Mean change in weight over 18 months. Additional outcomes included resting heart rate and blood pressure, waist circumference, body composition, fitness, physical activity, dietary intake, and cost of the program. RESULTS: Of the 363 participants randomized, 260 (71.6%) provided a measure of mean change in weight over 18 months. The 18-month intervention resulted in weight decreasing from 93.1 kg (95% CI, 91.0 to 95.2 kg) to 85.6 kg (95% CI, 83.4 to 87.7 kg) (P < .001) in the SBWI group and from 92.7 kg (95% CI, 90.8 to 94.6 kg) to 86.4 kg (95% CI, 84.5 to 88.4 kg) in the STEP group (P < .001). The percentage change in weight from baseline to 18 months was -8.1% (95% CI, -9.4% to -6.9%) in the SBWI group (P < .001) compared with -6.9% (95% CI, -8.0% to -5.8%) in the STEP group (P < .001). Although the between-group difference in 18-month weight loss was not statistically different (-1.3 kg [95% CI, -2.8 to 0.2 kg]; P = .09), there was a significant group × time interaction effect (P = .03). The cost per participant was $1357 (95% CI, $1272 to $1442) for the SBWI group vs $785 (95% CI, $739 to $830) for the STEP group (P < .001). Both groups had significant and comparable improvements in resting heart rate, blood pressure level, and fitness. CONCLUSIONS: Among overweight and obese adults, the use of SBWI resulted in a greater mean weight loss than STEP over 18 months. Compared with SBWI, STEP resulted in clinically meaningful weight loss that cost less to implement. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00714168.

Examining the Role of Nonsurgical Therapy in the Treatment of Geriatric Urinary Incontinence.

OBJECTIVE: To examine the role of physical function impairments on the change in urinary incontinence (UI) symptoms after pelvic floor muscle training in older women. METHODS: This is a prospective cohort study of 70 community-dwelling participants, older than age 70 years, with at least moderate incontinence symptoms. A comprehensive pelvic floor and physical function assessment was done at baseline. Individualized pelvic floor muscle training prescriptions with behavioral management strategies to reduce incontinence episodes were provided for 12 weeks. Baseline physical function was determined using the SPPB (Short Physical Performance Battery). A total score of 9 or lower out of 12 indicated impaired physical function, and scores higher than 9 indicated normal physical function. A 3-day bladder diary established daily incontinence episodes. The between-group difference in the change in number of UI episodes, from baseline to 6 weeks, was our primary outcome. Descriptive analyses compared important demographic and clinical characteristics. Longitudinal mixed model linear regression analyses determined the change in incontinence episodes and estimates of improvement based on the presence of impaired physical function and adjusted for age, race, and body mass index (BMI). RESULTS: Participants' mean±SD age was 76.9±5.4 years, and 15.7% identified as African American, with no significant differences in age or race between groups. Participants with impaired physical function had higher mean±SD BMI (33.6±14.5 vs 27.4±5.8; P=.03) and more baseline incontinence episodes (4.5±2.9 vs 2.7±2.1 episodes per day; P=.005) than in women without functional impairment. After 6 weeks of pelvic floor exercises, the change in number of incontinence episodes per day was not different between participants with physical functional impairment compared with women with normal physical function (mean [95% CI] -1.2 [-2.0 to -0.5] vs -0.4 [-1.1 to 0.3], P=.31). Overall, after 12 weeks of pelvic floor muscle training, complete satisfaction with incontinence symptom improvement was low for both groups (41.8% with physical function impairments vs 44.8% with normal physical function; P=.90). CONCLUSION: Behavioral therapy including pelvic floor muscle training may not significantly decrease UI symptoms to a degree that is satisfactory in women who are older than 70 years and are seeking treatment for UI, regardless of the presence of physical function impairments. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT03057834.

Estimating heterogeneity of physical function treatment response to caloric restriction among older adults with obesity.

Clinical trials conventionally test aggregate mean differences and assume homogeneous variances across treatment groups. However, significant response heterogeneity may exist. The purpose of this study was to model treatment response variability using gait speed change among older adults participating in caloric restriction (CR) trials. Eight randomized controlled trials (RCTs) with five- or six-month assessments were pooled, including 749 participants randomized to CR and 594 participants randomized to non-CR (NoCR). Statistical models compared means and variances by CR assignment and exercise assignment or select subgroups, testing for treatment differences and interactions for mean changes and standard deviations. Continuous equivalents of dichotomized variables were also fit. Models used a Bayesian framework, and posterior estimates were presented as means and 95% Bayesian credible intervals (BCI). At baseline, participants were 67.7 (SD = 5.4) years, 69.8% female, and 79.2% white, with a BMI of 33.9 (4.4) kg/m2. CR participants reduced body mass [CR: -7.7 (5.8) kg vs. NoCR: -0.9 (3.5) kg] and increased gait speed [CR: +0.10 (0.16) m/s vs. NoCR: +0.07 (0.15) m/s] more than NoCR participants. There were no treatment differences in gait speed change standard deviations [CR-NoCR: -0.002 m/s (95% BCI: -0.013, 0.009)]. Significant mean interactions between CR and exercise assignment [0.037 m/s (95% BCI: 0.004, 0.070)], BMI [0.034 m/s (95% BCI: 0.003, 0.066)], and IL-6 [0.041 m/s (95% BCI: 0.009, 0.073)] were observed, while variance interactions were observed between CR and exercise assignment [-0.458 m/s (95% BCI: -0.783, -0.138)], age [-0.557 m/s (95% BCI: -0.900, -0.221)], and gait speed [-0.530 m/s (95% BCI: -1.018, -0.062)] subgroups. Caloric restriction plus exercise yielded the greatest gait speed benefit among older adults with obesity. High BMI and IL-6 subgroups also improved gait speed in response to CR. Results provide a novel statistical framework for identifying treatment heterogeneity in RCTs.

Weight Change During the Postintervention Follow-up of Look AHEAD.

OBJECTIVE: Patients with type 2 diabetes are encouraged to lose weight, but excessive weight loss in older adults may be a marker of poor health and subsequent mortality. We examined weight change during the postintervention period of Look AHEAD, a randomized trial comparing intensive lifestyle intervention (ILI) with diabetes support and education (DSE) (control) in overweight/obese individuals with type 2 diabetes and sought to identify predictors of excessive postintervention weight loss and its association with mortality. RESEARCH DESIGN AND METHODS: These secondary analyses compared postintervention weight change (year 8 to final visit; median 16 years) in ILI and DSE in 3,999 Look AHEAD participants. Using empirically derived trajectory categories, we compared four subgroups: weight gainers (n = 307), weight stable (n = 1,561), steady losers (n = 1,731), and steep losers (n = 380), on postintervention mortality, demographic variables, and health status at randomization and year 8. RESULTS: Postintervention weight change averaged -3.7 ± 9.5%, with greater weight loss in the DSE than the ILI group. The steep weight loss trajectory subgroup lost on average 17.7 ± 6.6%; 30% of steep losers died during postintervention follow-up versus 10-18% in other trajectories (P < 0001). The following variables distinguished steep losers from weight stable: baseline, older, longer diabetes duration, higher BMI, and greater multimorbidity; intervention, randomization to control group and less weight loss in years 1-8; and year 8, higher prevalence of frailty, multimorbidity, and depressive symptoms and lower use of weight control strategies. CONCLUSIONS: Steep weight loss postintervention was associated with increased risk of mortality. Older individuals with longer duration of diabetes and multimorbidity should be monitored for excessive unintentional weight loss.

Predictors of Clinically Meaningful Gait Speed Response to Caloric Restriction Among Older Adults Participating in Weight Loss Interventions.

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.

Association of cognition with leptin and vascular endothelial growth factor in individuals with type 2 diabetes mellitus.

OBJECTIVE: The 10-year intensive lifestyle intervention (ILI) of the Look AHEAD study left a legacy of relative deficits in cognitive function among participants who entered the clinical trial with obesity or a history of cardiovascular disease. We hypothesized that altered levels of two weight-sensitive proangiogenic cytokines, leptin and vascular endothelial growth factor (VEGF), accounted for this concerning finding. METHODS: Serum leptin and VEGF concentrations were determined in 1,279 Look AHEAD participants at baseline, proximal to cessation of the interventions (Epoch 1), and an average of 4 years later (Epoch 2). Up to four standardized assessments of attention, executive function, and memory were collected during follow-up. Mixed effects models were used to assess relative differences in leptin and VEGF concentrations between intervention groups and whether these accounted for changes in cognitive composite scores. RESULTS: ILI and diabetes support and education differences in VEGF, but not leptin, concentrations varied depending on baseline history of cardiovascular disease and obesity, but neither leptin nor VEGF concentrations accounted for the relative decrements in cognitive function in participants assigned to ILI. CONCLUSIONS: Alterations in two weight-sensitive proangiogenic cytokines did not account for the long-term adverse effects of ILI on cognitive function among adults with diabetes and either obesity or cardiovascular disease.

Impact of dietary calcium and oxalate, and Oxalobacter formigenes colonization on urinary oxalate excretion.

PURPOSE: Enteric colonization with Oxalobacter formigenes, a bacterium whose main energy source is oxalate, has been demonstrated to decrease the risk of recurrent calcium oxalate kidney stone formation. We assessed the impact of diets controlled in calcium and oxalate contents on urinary and fecal analytes in healthy subjects who were naturally colonized with O. formigenes or not colonized with O. formigenes. MATERIALS AND METHODS: A total of 11 O. formigenes colonized and 11 noncolonized subjects were administered diets controlled in calcium and oxalate contents. We assayed 24-hour urine collections and stool samples obtained on the last 4 days of each 1-week diet for stone risk parameters and O. formigenes levels. Mixed model analysis was used to determine the effects of colonization status on these variables. RESULTS: Urinary calcium and oxalate excretion were significantly altered by the dietary changes in O. formigenes colonized and noncolonized individuals. Mixed model analysis showed significant interaction between colonization status and oxalate excretion on a low calcium (400 mg daily)/moderate oxalate (250 mg daily) diet (p = 0.026). Urinary oxalate excretion was 19.5% lower in O. formigenes colonized subjects than in noncolonized subjects on the low calcium/moderate oxalate diet (mean ± SE 34.9 ± 2.6 vs 43.6 ± 2.6 mg, p = 0.031). CONCLUSIONS: Results suggest that O. formigenes colonization decreases oxalate excretion during periods of low calcium and moderate oxalate intake.