Comparison of Strategies for Sustaining Weight Loss
Context Behavioral weight loss interventions achieve short-term success, but re-gain is common.
Objective To compare 2 weight loss maintenance interventions with a self-directed control group.
Design, Setting, and Participants Two-phase trial in which 1032 overweight or obese adults (38% African American, 63% women) with hypertension, dyslipidemia, or both who had lost at least 4 kg during a 6-month weight loss program (phase 1) were randomized to a weight-loss maintenance intervention (phase 2). Enrollment at 4 academic centers occurred August 2003-July 2004 and randomization, February-December 2004. Data collection was completed in June 2007.
Interventions After the phase 1 weight-loss program, participants were randomized to one of the following groups for 30 months: monthly personal contact, unlimited access to an interactive technology–based intervention, or self-directed control.
Main Outcome Changes in weight from randomization.
Results Mean entry weight was 96.7 kg. During the initial 6-month program, mean weight loss was 8.5 kg. After randomization, weight regain occurred. Participants in the personal-contact group regained less weight (4.0 kg) than those in the self-directed group (5.5 kg; mean difference at 30 months, −1.5 kg; 95% confidence interval [CI], −2.4 to −0.6 kg; P = .001). At 30 months, weight regain did not differ between the interactive technology–based (5.2 kg) and self-directed groups (5.5 kg; mean difference −0.3 kg; 95% CI, −1.2 to 0.6 kg; P = .51); however, weight regain was lower in the interactive technology–based than in the self-directed group at 18 months (mean difference, −1.1 kg; 95% CI, −1.9 to −0.4 kg; P = .003) and at 24 months (mean difference, −0.9 kg; 95% CI, −1.7 to −0.02 kg; P = .04). At 30 months, the difference between the personal-contact and interactive technology–based group was −1.2 kg (95% CI −2.1 to −0.3; P = .008). Effects did not differ significantly by sex, race, age, and body mass index subgroups. Overall, 71% of study participants remained below entry weight.
Conclusions The majority of individuals who successfully completed an initial behavioral weight loss program maintained a weight below their initial level. Monthly brief personal contact provided modest benefit in sustaining weight loss, whereas an interactive techonology–based intervention provided early but transient benefit.
Nearly two-thirds of US adults are overweight or obese. Together overweight and obesity are the second leading cause of preventable death, primarily through effects on cardiovascular disease (CVD) risk factors (hypertension, dyslipidemia, and type 2 diabetes). Weight loss improves these risk factors, and evidence suggests that benefits persist as long as weight loss is maintained. Relatively short-term (ie, 4-6 months) behavioral interventions for adults result in clinically significant weight loss, but regain is an intractable problem. Given the vast scope of the overweight and obesity epidemic, there is a critical need for practical, affordable, and scalable intervention strategies that effectively maintain weight loss. Such strategies may also play an important role in preventing weight gain among normal-weight individuals, thereby reducing the incidence of overweight and obesity.
Prediction of Erectile Function Following Treatment for Prostate Cancer. Part 3
Statistical Analysis
Having functional erections suitable for intercourse was defined as the patient selecting the response option of “firm enough for intercourse” to the EPIC-26 question, “How would you describe the usual quality of your erections during the last 4 weeks?” (other responses indicated erectile dysfunction). Erectile function 2 years after treatment was modeled separately, according to planned treatment, using logistic regression. The pretreatment patient and disease characteristics as well as planned treatment details considered are summarized in eTable 1.
Multivariable model development used a backward elimination selection procedure with 2-sided α = .05. Model selection was internally validated using bootstrap resampling (500 resamples), and bootstrap estimates of parameter estimates, standard errors, pointwise 95% confidence intervals for model-predicted probabilities, and area under the receiver operating characteristic curve (AUC) were also obtained for each final model. Individual predicted probabilities of functional erections at 2 years were calculated using the inverse logistic function {exp[X′β]/[1 + exp(X′β)]}, where X′β is the sum with X representing individual characteristics observed and β representing the associated log odds ratios for the individual characteristics estimated from the model.
The omission of 2-year nonrespondents from model development assumes data are missing completely at random. A sensitivity analysis assessed the effect of this assumption by refitting each final model using a model weighted for inverse probability of response; the probability of response was estimated using multivariable logistic regression including factors associated with nonresponse (education level, number of comorbid conditions, race, and pretreatment sexual functioning). This approach had little effect on the estimates, and results were not reported.
Use of medications or devices to assist erection function as measured by patient self-report at 2 years was summarized overall and in detail among the subset of 694 men who were potent (ie, reported functional erections) before treatment, excluding patients with implanted erectile aid devices.
All analyses were performed using SAS version 9.1 (SAS Institute Inc, Cary, North Carolina).
External Validation
The community-based Cancer of the Prostate Strategic Urologic Research Endeavor the CaPSURE cohort registry served as an external validation cohort for the developed models. Men in the CaPSURE cohort reported HRQOL at baseline and every 6 months in follow-up; sexual function and bother (severity and impact of patient-reported erectile dysfunction) were determined from the UCLA Prostate Cancer Index (UCLA-PCI), the instrument from which the EPIC-26 was previously derived and from which it retained 6 items. Characteristics of the CaPSURE cohort have been previously described.
Of the 1913 CaPSURE patients who completed pretreatment and 2 years posttreatment evaluation of sexual HRQOL using the UCLA-PCI, 1655 had data for all available model covariates available for validation. The PROSTQA model–predicted probability of 2-year erectile function was computed for each CaPSURE patient (from the inverse logistic function of the final model equations) and compared with his reported (actual) 2-year erectile function (the definition of erectile function used in the CaPSURE validation was the same as that in the PROSTQA cohort). Validation was assessed by AUC from fitting univariable logistic regression of reported 2-year erectile function on model-predicted probability, and calibration was assessed by examining the average model-predicted probability vs observed proportion of men reporting functional erections at 2 years, which is summarized overall and according to quintiles of the distribution of model-predicted probabilities.
Vitamin E and the Risk of Prostate Cancer. Part 2
With considerable preclinical and epidemiological evidence that selenium and vitamin E may reduce prostate cancer risk, we conducted and reported the results of a prospective randomized trial examining the effect of these 2 agents for prostate cancer prevention. Coordinated by SWOG, a federally funded cancer research cooperative group, the Selenium and Vitamin E Cancer Prevention Trial (SELECT) began accrual on August 22, 2001, and randomized 35 533 men into 4 groups: selenium with matching placebo, vitamin E with matching placebo, both agents, or placebo.
Based on a preplanned interim analysis, the independent data and safety monitoring committee met on September 15, 2008, and recommended the early discontinuation of study supplements because of lack of efficacy for risk reduction and because futility analysis demonstrated no possibility of benefit to the planned degree with additional follow-up.6
As reported in the initial article,6 with a median follow-up of 5.5 years, the numbers of prostate cancers detected were 473 (hazard ratio [HR], 1.13; 99% CI, 0.95-1.35) for vitamin E; 432 (HR, 1.04; 99% CI, 0.87-1.24) for selenium; 437 (HR, 1.05; 99% CI, 0.88-1.25) for selenium plus vitamin E; and 416 (HR, 1.0) for placebo. Although these results were not statistically significant, the data and safety monitoring committee expressed concern about the increased risk of prostate cancer observed in the vitamin E plus placebo group, which approached statistical significance (P = .06) and a statistically nonsignificant increased risk of type 2 diabetes mellitus in the selenium plus placebo group (P = .16).
Since that time, participant follow-up has continued, allowing observation of additional events. On May 20, 2011, the data and safety monitoring committee reviewed trial data and recommended reporting the finding regarding increased risk of prostate cancer with vitamin E. This recommendation was based on final data collection from the study sites and coincided with the preplanned final analysis at 7 years after the last participant was randomized. Viagra professional Australia
Detailed descriptions of the rationale, design, conduct, and initial results of SELECT have been previously published. The study enrolled healthy men at average risk of prostate cancer based on a baseline prostate-specific antigen (PSA) of ≤4 ng/mL and normal digital rectal examination (DRE) commencing at age 50 years for black men or at age 55 years for all others. Men were randomized into 1 of 4 groups: selenium (200 μg/d from L-selenomethionine) with matching vitamin E placebo, vitamin E (400 IU/d of all rac -α-tocopherol acetate) with matching selenium placebo, both agents, or matching placebo.
Participants without prostate cancer were monitored every 6 months with an annual limited physical examination including blood pressure, weight, and smoking status; participants who developed prostate cancer during the study were monitored annually thereafter. Participants were recommended to undergo PSA and DRE testing and prostate biopsy based on the standard of care in their community and in accordance with the participant's preference. To facilitate adherence, a multivitamin containing no selenium or vitamin E was offered. All participants were required to provide written informed consent and the local institutional review board of each study site approved the study.