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Biomedical subjects

M Kiernan

Publications and source records attributed to M Kiernan.

At least 19 recordsLinked to original sources
PubMed2001

Do logistic regression and signal detection identify different subgroups at risk? Implications for the design of tailored interventions.

Identifying subgroups of high-risk individuals can lead to the development of tailored interventions for those subgroups. This study compared two multivariate statistical methods (logistic regression and signal detection) and evaluated their ability to identify subgroups at risk. The methods identified similar risk predictors and had similar predictive accuracy in exploratory and validation samples. However, the 2 methods did not classify individuals into the same subgroups. Within subgroups, logistic regression identified individuals that were homogeneous in outcome but heterogeneous in risk predictors. In contrast, signal detection identified individuals that were homogeneous in both outcome and risk predictors. Because of the ability to identify homogeneous subgroups, signal detection may be more useful than logistic regression for designing distinct tailored interventions for subgroups of high-risk individuals.

Adult↗
PubMed2001

Men gain additional psychological benefits by adding exercise to a weight-loss program.

OBJECTIVE: Adding exercise to a comprehensive weight-loss program might not only attenuate any psychological distress associated with weight-loss attempts but also may provide psychological benefits. This study examined whether a diet-plus-exercise weight-loss program improved psychological outcomes more than a diet-only weight-loss program or an assessment-only control group. RESEARCH METHODS AND PROCEDURES: This study was part of a larger 1-year randomized weight-loss trial examining the effects of diet and exercise on cardiovascular disease risk factors in 264 overweight adults. Psychological measures specific to weight control (e.g., cognitive restraint, disinhibition, hunger, and body dissatisfaction) as well as traditional measures of psychological distress (e.g., symptoms of depression, anxiety, and stress) were obtained at baseline and 1 year. RESULTS: Men and women in either weight-loss program reported greater restraint, less disinhibition, and less hunger at 1 year than those in no program. Men in the diet-plus-exercise program experienced additional increases in restraint and decreases in hunger than did men in the diet-only program. Women in the diet-plus-exercise program did not experience additional psychological benefits specific to weight control than those in the diet-only program, despite increases in aerobic capacity. DISCUSSION: The pattern seen for overweight men in the diet-plus-exercise program at 1 year-greater restraint, less disinhibition, and less hunger-is similar to the pattern seen in successful weight maintainers. These results underscore the need for innovative strategies that will enhance and sustain the pattern of psychological benefits specific to weight control associated with successful weight loss, especially for overweight women.

Adult↗
PubMed2000

Identifying patients for weight-loss treatment: an empirical evaluation of the NHLBI obesity education initiative expert panel treatment recommendations.

BACKGROUND: The NHLBI (National Heart, Lung, and Blood Institute) Obesity Education Initiative Expert Panel recently proposed that clinicians and other health care professionals use a new treatment algorithm to identify patients for weight-loss treatment. In addition to the usual assessment of body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters), the new algorithm includes the assessment of abdominal obesity (as measured by waist circumference) and other cardiovascular disease (CVD) risk factors. METHODS: We examined the percentage of adults meeting the criteria of the panel's treatment algorithm: BMI > or =30 or ¿[BMI, 25.0-29.9 or waist circumference >88 cm (women) >102 cm (men)] and > or = 2 CVD risk factors¿ in a sample of 2844 black, 2754 Mexican American, and 3504 white adults, aged 25 to 64 years, from the Third National Health and Nutrition Examination Survey, 1988-1994. RESULTS: Across ethnic groups, more than 98% of adults (normal weight, overweight, and obese) received the same treatment recommendations using the panel's algorithm and an algorithm based only on BMI and CVD risk factors, without waist circumference. For normal-weight adults, almost none (0.0%-1.8%) had a large waist circumference as defined above and 2 or more CVD risk factors. Using the usual criterion of a BMI of 30 or higher, a substantial percentage of at-risk overweight women and men (BMI, 25.0-29.9) with 2 or more CVD risk factors were missed (8.4% and 19.3%, respectively). CONCLUSIONS: Despite the potential importance of abdominal obesity as a CVD risk factor, these results challenge the clinical utility of including waist circumference in this new algorithm and suggest that using BMI and CVD risk factors may be sufficient.

Adult↗
PubMed2000

Using direct mail to recruit Hispanic adults into a dietary intervention: an experimental study.

Identifying strategies for successful recruitment of ethnic minorities into scientific studies is critical. Without effective methods, investigators may fail to recruit the desired sample size, take longer to recruit than planned, and delay progress for research in minority health. Direct mail is an appealing recruitment method because of the potential for reaching large target populations and producing a high volume of inquiries about a study with relatively little staff effort. To determine which of three direct mail strategies yielded higher recruitment, 561 Hispanic employees were randomly assigned to receive either: (a) a flyer about a worksite dietary intervention; (b) the same flyer plus a personalized hand-signed letter containing heart disease risk statistics for the general American population; or (c) the flyer plus a personalized hand-signed letter containing statistics for Hispanics. Two orthogonal chi-square comparisons were examined. The personalized letters plus flyer yielded a significantly higher response rate (7.8%) than the flyer alone (2.1%), X2(1, N = 561) = 7.5, p = .006. However, the personalized letter with Hispanic heart disease risk statistics did not yield a statistically significant higher response rate (9.1%) than the letter with the general population risk statistics (6.5%), X2(1, N = 370) = 0.9, p > .34. These findings suggest that personalized approaches can increase the effectiveness of direct mail efforts for recruiting ethnic minorities into interventions and may be particularly helpful for large-scale interventions.

Adult↗
PubMed2000

Central exendin-4 infusion reduces body weight without altering plasma leptin in (fa/fa) Zucker rats.

OBJECTIVE: To investigate whether chronic administration of the long-acting glucagon-like peptide-1 receptor agonist exendin-4 can elicit sustained reductions in food intake and body weight and whether its actions require an intact leptin system. RESEARCH METHODS AND PROCEDURES: Male lean and obese Zucker (fa/fa) rats were infused intracerebroventricularly with exendin-4 using osmotic minipumps for 8 days. RESULTS: Exendin-4 reduced body weight in both lean and obese Zucker rats, maximum suppression being reached on Day 5 in obese (8%) and Day 7 in lean (16%) rats. However, epididymal white adipose tissue weight was not reduced, and only in lean rats was there a reduction in plasma leptin concentration. Food intake was maximally suppressed (by 81%) on Day 3 in obese rats but was reduced by only 18% on Day 8. Similarly, in lean rats food intake was maximally reduced (by 93%) on Day 4 of treatment and by 45% on Day 8. Brown adipose tissue temperature was reduced from Days 2 to 4. Plasma corticosterone was elevated by 76% in lean but by only 28% in obese rats. DISCUSSION: Chronic exendin-4 treatment reduced body weight in both obese and lean Zucker rats by reducing food intake: metabolic rate was apparently suppressed. These effects did not require an intact leptin system. Neither does the absence of an intact leptin system sensitize animals to exendin-4. Partial tolerance to the anorectic effect of exendin-4 in lean rats may have been due to elevated plasma corticosterone and depressed plasma leptin levels, but other counter-regulatory mechanisms seem to play a role in obese Zucker rats.

Adipose Tissue↗
PubMed2000

Selective non-ablative wrinkle reduction by laser.

BACKGROUND AND OBJECTIVES: Skin resurfacing and wrinkle removal is a large medical laser market. However, the rate of undesirable side effects is high and sometimes is not warranted by the aesthetic improvement observed. The authors have evaluated the potential benefits of an approach to selective non-ablative wrinkle reduction. MATERIALS AND METHODS: This technique selectively targets the microvasculature which plays a key role in the stimulation of enhanced collagen production. RESULTS: The study reported shows that application of the laser parameters described enhances collagen production by an average of 84%, measured 72 hours after a single laser treatment. This is achieved whilst leaving the skin barrier intact and with no adverse pigmentary changes. The study further shows that a cosmetic improvement is observed with an average value of 1.88 reduction in wrinkle appearance as measured on the Fitzpatrick Wrinkle Severity scale. This improvement was achieved with one brief treatment and no reported incidence of side effects. CONCLUSION: In conclusion, the treatment modality described may be a new approach to the treatment of wrinkles.

Adult↗
PubMed2000

Methodologic issues in measuring physical activity and physical fitness when evaluating the role of dietary supplements for physically active people.

Physical activity and physical fitness are complex entities comprising numerous diverse components that present a challenge in terms of accurate, reliable measurement. Physical activity can be classified by its mechanical (static or dynamic) or metabolic (aerobic or anaerobic) characteristics and its intensity (absolute or relative to the person's capacity). Habitual physical activity can be assessed by using a variety of questionnaires, diaries, or logs and by monitoring body movement or physiologic responses. Selection of a measurement method depends on the purpose of the evaluation, the nature of the study population, and the resources available. The various components of physical fitness can be assessed accurately in the laboratory and, in many cases, in the field by using a composite of performance tests. Most coaches and high-level athletes would accept as very beneficial a dietary supplement that would increase performance in a competitive event by even 3%; for example, lowering a runner's time of 3 min, 43 s in the 1500 m by 6.7 s. To establish that such small changes are caused by the dietary supplement requires carefully conducted research that involves randomized, placebo-controlled, double-blind studies designed to maximize statistical power. Statistical power can be increased by enlarging sample size, selecting tests with high reliability, selecting a potent but safe supplement, and maximizing adherence. Failure to design studies with adequate statistical power will produce results that are unreliable and will increase the likelihood that a true effect will be missed.

Data Collection↗
PubMed1998

The effects of marital transitions on changes in physical activity: results from a 10-year community study.

The potential effects of making a marital transition on subsequent physical activity were evaluated across a ten-year period in a population-based sample of 302 women and 256 men ages 25 to 75 years. Subjects completed a structured interview at five timepoints throughout the ten-year period during which they reported on their physical activity level as well as marital status. The transition from a married to a single state did not affect physical activity relative to remaining married when analyses of either slopes or mean values were used. In contrast, the transition from a single to a married state resulted in significant positive changes in physical activity relative to remaining single throughout the study period when physical activity slopes, though not means, were compared. The results suggest that marriage may potentially set the stage for natural changes in physical activity that could be capitalized on through appropriate intervention, but additional research is needed to verify this in light of the inconsistent pattern of findings.

Adolescent↗
PubMed1998

Characteristics of successful and unsuccessful dieters: an application of signal detection methodology.

Signal detection methods were used to identify predictors of successful weight loss in 177 mildly to moderately overweight women and men assigned to one of two weight-loss programs. Predictors included initial demographic, physiological, behavioral, and psychosocial characteristics, and program type (e.g. diet-only and diet-plus-exercise). Successful weight loss was defined as a loss of at least two units of body mass index at one year. Four subgroups were identified. Participants in the diet-plus-exercise program who were initially more satisfied with their bodies and did not have a history of repeated weight loss were most likely to succeed (63% succeeded). In contrast, participants assigned to the diet-plus-exercise program who were either extremely dissatisfied with their bodies or who had a history of repeated weight loss were at similar risk for failure as participants in the diet-only program (only 26% to 35% succeeded). The results underscore the potential utility of exploring these subgroups further to inform the development of new treatment strategies to increase the likelihood of success.

Adult↗