Association of sedentary behavior and metabolic syndrome.

OBJECTIVES: To examine the association of sedentary behavior (SB) with metabolic syndrome (MetS) in adults, as well as to identify the impact of physical inactivity and economic condition on such association. STUDY DESIGN: This is a cross-sectional study. METHODS: This study was conducted in the city of Bauru, São Paulo State, Brazil (n = 970). Television (TV) viewing and physical activity (PA) were assessed by questionnaire. MetS was assessed via medical records. Descriptive statistics and binary logistic regression were used in data analyses. RESULTS: Participants with moderate TV viewing were associated with MetS when compared with low TV viewing group, even after adjustments for age, sex, economic status, smoking, and PA (odds ratio [OR] = 1.49 [95% confidence interval {CI}: 1.01-2.20]). The fully adjusted model showed an association between high exposure to TV viewing with MetS (OR = 1.77 [95%CI: 1.11-2.82]). The combination of physical inactivity and high TV viewing boosted the likelihood of having MetS (OR = 1.89 [95%CI: 1.08-3.29]). CONCLUSION: The results of the present study suggest that moderate and high TV viewing time is associated with the presence of MetS, mainly in insufficiently active adults and those living in lower economic condition.

Individuals with obesity but no other metabolic risk factors are not at significantly elevated all-cause mortality risk in men and women.

Studies have examined mortality risk for metabolically healthy obesity, defined as zero or one metabolic risk factors but not as zero risk factors. Thus, we sought to determine the independent mortality risk associated with obesity or elevated glucose, blood pressure or lipids in isolation or clustered together. The sample included 54 089 men and women from five cohort studies (follow-up = 12.8 ± 7.2 years and 4864 [9.0%] deaths). Individuals were categorized as having obesity or elevated glucose, blood pressure or lipids alone or clustered with obesity or another metabolic factor. In our study sample, 6% of individuals presented with obesity but no other metabolic abnormalities. General obesity (hazard ratios [HR], 95% CI = 1.10, 0.8-1.6) and abdominal obesity (HR = 1.24, 0.9-1.7) in the absence of metabolic risk factors were not associated with mortality risk compared to lean individuals. Conversely, diabetes, hypertension and dyslipidaemia in isolation were significantly associated with mortality risk (HR range = 1.17-1.94, P < 0.05). However, when using traditional approaches, obesity (HR = 1.12, 1.02-1.23) is independently associated with mortality risk after statistical adjustment for the other metabolic risk factors. Similarly, metabolically healthy obesity, when defined as zero or one risk factor, is also associated with increased mortality risk (HR = 1.15, 1.01-1.32) as compared to lean healthy individuals. Obesity in the absence of metabolic abnormalities may not be associated with higher risk for all-cause mortality compared to lean healthy individuals. Conversely, elevation of even a single metabolic risk factor is associated with increased mortality risk.

Construct Validation of the Dietary Inflammatory Index among African Americans.

OBJECTIVE: Chronic inflammation is linked to many chronic conditions. One of the strongest modulators of chronic inflammation is diet. The Dietary Inflammatory Index (DII) measures dietary inflammatory potential and has been validated previously, but not among African Americans (AAs). DESIGN: Cross-sectional analysis using baseline data from the Healthy Eating and Active Living in the Spirit (HEALS) intervention study. SETTING: Baseline data collection occurred between 2009 and 2012 in or near Columbia, SC. PARTICIPANTS: African-American churchgoers. MEASUREMENTS: Baseline data collection included c-reactive protein (CRP) and interleukin-6 from blood draws, anthropometric measures, and numerous questionnaires. The questionnaires included a food frequency questionnaire which was used for DII calculation. The main analyses were performed using quantile regression. RESULTS: Subjects in the highest DII quartile (i.e., more pro-inflammatory) were younger, more likely to be married, and had less education and greater BMI. Individuals in DII quartile 4 had statistically significantly greater CRP at the 75th and 90th percentiles of CRP versus those in quartile 1 (i.e., more anti-inflammatory). CONCLUSION: Construct validation provides support for using the DII in research among AA populations. Future research should explore avenues to promote more anti-inflammatory diets, with use of the DII, among AA populations to reduce risk of chronic disease.

Physical activity, eating traits and weight in young adulthood: a cross-sectional and longitudinal study.

OBJECTIVE: To investigate the association between eating traits (e.g. dietary restraint or opportunistic eating) and weight - both cross-sectionally and longitudinally - and whether physical activity (PA) moderates these associations. METHODS: Two-hundred seventy young adults (21-35 years; BMI: 25.40 kg/m2 [SD = 3.90 kg/m2]; 48.90% female) participated in this 12-month observational cohort study. Cognitive Restraint (CR), Disinhibition (DI) and Hunger (HU) were measured using the Three-Factor Eating Questionnaire at baseline and 12 months. Participants were measured at quarterly intervals for objectively measured PA and anthropometrics. Cross-sectional and longitudinal models determined if eating traits were associated with weight or weight change, and whether these associations were moderated by PA. RESULTS: At baseline, higher CR (B = 0.429, p < 0.01) and DI (B = 0.942, p < 0.01) were associated with higher weight. The associations of DI (B = -0.008 p = 0.02) and HU (B = -0.006, p = 0.04) with weight were moderated by PA at baseline. The longitudinal model for CR determined PA altered the relationship between change in CR and weight change (B = 0.004, p < 0.01). CONCLUSIONS: Eating traits and PA are associated with weight and weight change. However, to elucidate how PA and eating traits directly affect weight changes, future weight loss interventions should investigate whether improving eating traits and concomitantly increasing PA amplify weight loss.

The association of change in physical activity and body weight in the regulation of total energy expenditure.

BACKGROUND/OBJECTIVES: The limited success in addressing the current obesity epidemic reflects the insufficient understanding of the regulation of energy balance. The present study examines the longitudinal association of body weight with physical activity (PA), total daily energy expenditure (TDEE) and total daily energy intake (TDEI). SUBJECTS/METHODS: A total of 195 adults (52% male) between 21 and 35 years of age with no intention for weight loss were followed over a 2-year period. Body weight, fat mass and fat-free mass were measured every 3 months. Participants were stratified into three groups based on change in body weight using a 5% cutpoint. TDEE and time spent in different PA intensities were determined via a multisensor device at each measurement time. TDEI was calculated based on change in body composition and TDEE. RESULTS: At 2-year follow-up, 57% of the participants maintained weight, 14% lost weight and 29% gained weight. Average weight change was -6.9±3.4 and 7.1±3.6 kg in the weight-loss and weight-gain groups, respectively. Average TDEE and TDEI did not change significantly in any weight change group (P>0.16). Moderate-to-vigorous PA, however, increased significantly in the weight-loss group (35±49 min/day; P<0.01) and decreased in the weight-gain group (-35±46 min/day; P<0.01). CONCLUSIONS: Results of this observational study indicate an inverse association between body weight and PA to maintain a stable TDEE and allow for a stable TDEI over time. Sufficient PA levels, therefore, are an important contributor to weight loss maintenance.

High respiratory quotient is associated with increases in body weight and fat mass in young adults.

BACKGROUND/OBJECTIVES: Metabolic disturbances, such as reduced rates of fat oxidation (high respiratory quotient (RQ)) or low energy expenditure (low resting metabolic rate (RMR)), may contribute to obesity. The objective was to determine the association between a high RQ or a low RMR and changes in body weight and body composition over 1 year. SUBJECTS/METHODS: We measured RQ and RMR in 341 adults using indirect calorimetry, along with body weight/body composition using dual-energy X-ray absorptiometery, energy expenditure using an arm-based activity monitor and energy intake using dietary recalls. Participants were classified into low, moderate or high RQ and RMR (adjusted for age, sex, race and body composition) groups according to tertiles by sex. Follow-up measurements were completed every 3 months. RESULTS: Individuals with a high RQ had larger gains in body weight and fat mass compared with individuals with a low/moderate RQ at month 3, and increases in fat mass were more than double among individuals with a high RQ at 12 months (1.3±3.0 vs 0.6±3.7 kg, P=0.03). Individuals with a low RMR did not gain more body weight nor fat mass compared with individuals with a moderate/high RMR. CONCLUSION: The primary finding is a high RQ is predictive of gains in body weight and fat mass over a 12-month period among young adults, with changes occurring as soon as 3 months. In addition, a low RMR was not associated with gains in body weight or fat mass over the same period.

Weight change after 20 years of age and the incidence of dyslipidemia: a cohort study of Japanese male workers.

BACKGROUND: While heavier weight is known to increase the incidence of dyslipidemia, limited data are available on the relationship between weight gain and its development. METHODS: A total of 2647 males were categorized into the following four groups according to the difference between their self-reported weight at 20 years of age and their measured weight in 1994-95: a loss of ≥5% (decrease), loss of <5% or gain of <5% (no change), gain of ≥5 to <15% (increase) and gain of ≥15% (sizable increase). They were followed up until their 2002-03 health examination. Using the 'no change' group as reference, the multivariable-adjusted odds ratio (adjusted for age, body mass index at 20 years of age, physical activity, smoking and alcohol intake) and 95% confidence interval (95% CI) for the incidence of dyslipidemia were determined using logistic regression models. RESULTS: A total of 1342 participants developed dyslipidemia during the follow-up period. The 'increase' and 'sizable increase' groups had odds ratios for the incidence of dyslipidemia of 1.97 (95% CI, 1.59-2.45) and 2.68 (2.15-3.34), respectively, demonstrating that there was a significant dose-response association between weight gain since 20 years of age and the incidence of dyslipidemia (P < 0.001 for trend). CONCLUSION: These results suggest that dyslipidemia could be prevented by avoiding weight gain in adulthood.

Prospective association between body composition, physical activity and energy intake in young adults.

BACKGROUND/OBJECTIVES: Despite considerable research on the association between physical activity (PA) and body composition, there remains limited information on the directionality of the relationship. The present study examined the prospective associations among objectively measured PA, energy intake (EI) and body composition. SUBJECTS/METHODS: A convenience sample of 430 adults (49% male) between 21 and 35 years of age was followed over 1 year with repeated measurements taken every 3 months. BMI (kg/m(2)) and percent body fat (%BF) were calculated based on anthropometric measurements and dual energy X-ray absorptiometry. A multi-sensor device was worn over a period of 10 days to estimate total daily energy expenditure and time spent in different intensities. EI was calculated based on change in body composition and total daily energy expenditure. RESULTS: A total of 379 participants provided valid data. On average, participants experienced a significant weight gain of 1.2±4.3 kg during the 12-month observation period, which was associated with an increase in %BF (0.8±3.2 %). Average time spent in moderate-to-vigorous PA (MVPA) decreased significantly, whereas EI remained constant. Optimal linear mixed models, adjusting for age and sex, showed an inverse effect of MVPA on BMI and %BF, whereas EI only directly affected BMI (P<0.001). There was also a significant inverse effect of BMI and %BF on MVPA (P<0.001). CONCLUSIONS: Results of this study indicate an inverse reciprocal association between MVPA and measures of adiposity. Thus, primary preventive actions are warranted to avoid excess weight gain, which may result in a vicious cycle of weight gain and low PA.

Aerobic and resistance training improves mood state among adults living with HIV.

The purpose of this investigation was to examine the effects of combined aerobic and resistance exercise training among self-reported mood disturbances, perceived stress, frequency of self-reported symptoms, and symptom distress in a sample of HIV+ adults. For this purpose, 49 participants were randomly assigned into an exercise (EX) or control (CON) group. Those in the EX group completed 50 min of supervised aerobic and resistance training at a moderate intensity twice a week for 6 weeks. The CON group reported to the university and engaged in sedentary activities. Data were collected at baseline before randomization and 6 weeks post intervention. Measures included the symptom distress scale (SDS), perceived stress scale (PSS), profile of mood states (POMS) total score, and the POMS sub-scale for depression and fatigue. A 2 way ANOVA was used to compare between and within group interactions. The EX group showed a significant decrease in reported depression scores (p=0.03) and total POMS (p=0.003). The CON group reported no change in POMS or SDS, but showed a significant increase in PSS. These findings indicate that combination aerobic and resistance training completed at a moderate intensity at least twice a week provides additional psychological benefits independent of disease status and related symptoms.

Body adiposity index and incident hypertension: the Aerobics Center Longitudinal Study.

BACKGROUND AND AIM: The body adiposity index (BAI) has been recently proposed as a new method to estimate the percentage of body fat. The association between BAI and hypertension risk has not been investigated yet. The aim of our study was to evaluate the ability of BAI to predict hypertension in males and females compared with traditional body adiposity measures. METHODS AND RESULTS: The present follow-up analysis comprised 10,309 individuals (2259 females) free of hypertension from the Aerobics Center Longitudinal Study, who completed a baseline examination between 1988 and 2003. Body adiposity measures included BAI, body mass index (BMI), waist circumference, hip circumference, percentage of body fat and waist to hip ratio (WHR). Incident hypertension was ascertained from responses to mail-back surveys between 1990 and 2004. During an average of 9.1 years of follow-up, 872 subjects (107 females) became hypertensive. Hazard ratios (HRs) and 95% confidence intervals (95% CI) showed that males in the highest categories of all body adiposity measures showed a higher incident risk of hypertension (HRs ranged from 1.37 to 2.09). Females showed a higher incident risk of hypertension only in the highest categories of BAI, BMI and WHR (HRs ranged from 1.84 to 3.36). CONCLUSION: Our results suggest that in order to predict incident hypertension BAI could be considered as an alternative to traditional body adiposity measures.

Exercise therapy - the public health message.

Non-communicable chronic diseases (NCDs), such as cardiovascular disease, diabetes, and cancer, are currently responsible for 65% of all deaths worldwide and are projected to cause over 75% of all deaths by 2030. A substantial accumulation of epidemiological and experimental evidence has established a causal relationship between NCDs and well-known yet preventable risk factors (e.g., physical inactivity and obesity). Given that physical activity has both direct and indirect effects on the mortality and morbidity of NCDs via other risk factors (e.g., obesity, diabetes, and hypertension), it is now undeniable that sedentary lifestyles are one of the most significant public health problems of the 21st century. In 2007, the American College of Sports Medicine (ACSM) and American Medical Association (AMA) launched the Exercise is Medicine® (EIM) initiative in recognition of the fundamental importance of physical activity to health and well-being. EIM is on the forefront of a global movement to reduce sedentary lifestyles, foster implementation of exercise counseling into clinical practice, and disseminate exercise therapy on a global scale. If the devastating human losses and financial burden of inactivity-induced chronic disease are to be ameliorated, the wide-ranging cost-effective health benefits and financial feasibility of physical activity interventions must be appreciated and promoted.

Comparisons of leisure-time physical activity and cardiorespiratory fitness as predictors of all-cause mortality in men and women.

OBJECTIVE: To examine the combined associations and relative contributions of leisure-time physical activity (PA) and cardiorespiratory fitness (CRF) with all-cause mortality. DESIGN: Prospective cohort study. Setting Aerobics centre longitudinal study. PARTICIPANTS: 31,818 men and 10 555 women who received a medical examination during 1978-2002. Assessment of risk factors Leisure-time PA assessed by self-reported questionnaire; CRF assessed by maximal treadmill test. Main outcome measures All-cause mortality until 31 December 2003. RESULTS: There were 1492 (469 per 10,000) and 230 (218 per 10,000) deaths in men and women, respectively. PA and CRF were positively correlated in men (r = 0.49) and women (r = 0.47) controlling for age (p < 0.001 for both). PA was inversely associated with mortality in multivariable Cox regression analysis among men, but the association was eliminated after further adjustment for CRF. No significant association of PA with mortality was observed in women. CRF was inversely associated with mortality in men and women, and the associations remained significant after further adjustment for PA. In the PA and CRF combined analysis, compared with the reference group "not meeting the recommended PA (< 500 metabolic equivalent-minute/week) and unfit", the relative risks (95% CIs) of mortality were 0.62 (0.54 to 0.72) and 0.61 (0.44 to 0.86) in men and women "not meeting the recommended PA and fit", 0.96 (0.61 to 1.53) and 0.93 (0.33 to 2.58) in men and women "meeting the recommended PA and unfit" and 0.60 (0.51 to 0.70) and 0.56 (0.37 to 0.85) in men and women "meeting the recommended PA and fit", respectively. CONCLUSIONS: CRF was more strongly associated with all-cause mortality than PA; therefore, improving CRF should be encouraged in unfit individuals to reduce risk of mortality and considered in the development of future PA guidelines.

Physical fitness levels among European adolescents: the HELENA study.

OBJECTIVE: To report sex- and age-specific physical fitness levels in European adolescents. METHODS: A sample of 3428 adolescents (1845 girls) aged 12.5-17.49 years from 10 European cities in Austria, Belgium, France, Germany, Greece (an inland city and an island city), Hungary, Italy, Spain and Sweden was assessed in the Healthy Lifestyle in Europe by Nutrition in Adolescence study between 2006 and 2008. The authors assessed muscular fitness, speed/agility, flexibility and cardiorespiratory fitness using nine different fitness tests: handgrip, bent arm hang, standing long jump, Bosco jumps (squat jump, counter movement jump and Abalakov jump), 4×10-m shuttle run, back-saver sit and reach and 20-m shuttle run tests. RESULTS: The authors derived sex- and age-specific normative values for physical fitness in the European adolescents using the LMS statistical method and expressed as tabulated percentiles from 10 to 100 and as smoothed centile curves (P5, P25, P50, P75 and P95). The figures showed greater physical fitness in the boys, except for the flexibility test, and a trend towards increased physical fitness in the boys as their age increased, whereas the fitness levels in the girls were more stable across ages. CONCLUSIONS: The normative values hereby provided will enable evaluation and correct interpretation of European adolescents' fitness status.

Association of white blood cell subfraction concentration with fitness and fatness.

OBJECTIVE: To examine the association between fitness, BMI, and neutrophil, lymphocyte, monocyte, basophil, and eosinophil concentrations in apparently healthy, non-smoking men. DESIGN: Cross-sectional study of 452 men from the Aerobics Center Longitudinal Study examining the resting concentration of white blood cell subfractions across fitness (maximal METs during a treadmill exercise test) and fatness (BMI) categories after adjusting for age. RESULTS: Fitness was inversely associated with all WBC subfraction concentrations. After further adjustment for BMI, only total WBC, neutrophil, and basophil concentrations remained significantly associated with fitness. BMI was directly associated with total WBC, neutrophil, lymphocyte, monocyte, and basophil concentrations and, when fitness was added to the model, only monocytes lost significance. CONCLUSION: Fitness (inversely) and fatness (directly) are associated with WBC subfraction populations.

Obesity, coffee consumption and CRP levels in postmenopausal overweight/obese women: importance of hormone replacement therapy use.

BACKGROUND/OBJECTIVES: Obesity is associated with an inflammatory state that is often characterized by elevated plasma C-reactive protein (CRP) levels. Although coffee is broadly consumed in Western societies, few studies have examined the relationship between obesity, coffee consumption and CRP levels. The objective of this study was to assess the relationship between obesity, coffee consumption and variation in CRP in postmenopausal, overweight/obese women with or without hormone replacement therapy (HRT) use. SUBJECTS/METHODS: Cross-sectional analyses of 344 healthy sedentary, overweight/obese postmenopausal women (mean age=57.1+/-6.4 years and mean body mass index (BMI)=36.1+/-3.9 kg/ m(2)). Plasma CRP levels were measured by a highly sensitive immunoassay that used monoclonal antibodies coated with polystyrene particles. Diet was assessed using the Food Intake and Analysis System semiquantitative food frequency questionnaire. RESULTS: Plasma CRP was positively associated with BMI (P<0.001) and negatively associated with coffee consumption (P

Myopia and later physical activity in adolescence: a prospective study.

OBJECTIVES: To investigate associations between objectively measured physical activity (PA) and myopia in children. METHODS: Children from the Avon Longitudinal Study of Parents and Children (ALSPAC) were asked to wear a uniaxial accelerometer for 7 days. Measures of counts per minute (cpm), minutes spent in moderate to vigorous activity (MVPA) and minutes of sedentary behaviour (msed) were derived from the accelerometer worn at age 12. Children were also examined, at age 10, using an autorefractor to estimate myopia. Social and parental factors were collected from pregnancy and physical measures of the child were recorded at age 12. RESULTS: 4880 children had valid PA and autorefraction data. In minimally adjusted models (age and gender) myopic children were less active than the other children: beta = -49.9 cpm (95% CI -73.5 to -26.4, p = <0.001). The myopic group spent less time in MVPA than the other children: beta = -3.2 minutes MVPA (95% CI -5.2 to -1.1, p = 0.003) and more time sedentary: beta = 15.8 minutes (95% CI 5.8 to 25.8, p = 0.002). The effect sizes were attenuated by adjustment for social and behavioural confounders although myopia status in the better (less myopic on autorefraction) eye remained strongly associated with cpm and MVPA but less so for sedentary behaviour: beta = -36.8 cpm (95% CI -67.8 to -5.8, p = 0.02), beta = -2.7 MVPA (95% CI -5.3 to -0.1, p = 0.04), beta = 10.1 msed (95% CI -2.9 to 23.1, p = 0.13). CONCLUSION: Myopic children may be more at risk of having lower levels of PA than their non-myopic peers, although the difference was modest.

Does physical activity ameliorate the health hazards of obesity?

Obesity is an established risk factor for chronic disease and premature death, but losing weight and keeping it off is difficult. Therefore, although obese individuals may know that they are at higher risk of disease and early death, they still may not be able to lose weight and maintain weight loss. Perhaps health professionals should focus less on weight and more on how to enhance and maintain health for people of all sizes and shapes.

Prevention and Reduction of Obesity through Active Living (PROACTIVE): rationale, design and methods.

The Prevention and Reduction of Obesity through Active Living (PROACTIVE) is a randomised controlled trial to evaluate the effectiveness of a behaviourally based physical activity and diet composition programme to prevent and reduce obesity and related comorbidities in a primary healthcare setting. 491 abdominally obese men and women 25-75 years of age who were patients of primary care physicians were randomly assigned to either a usual care group (N = 242) or a behavioural intervention group (N = 249). Those in usual care received general advice from the physician regarding the merits of physical activity and a healthy diet as a strategy for obesity reduction. Those in the behavioural intervention group received an individually designed counselling programme from a specially trained health educator, with respect to physical activity, diet and obesity reduction. The study was designed to provide 95% power in both men and women to detect a 2% (2 cm) difference in waist circumference and 80% power to identify a 15% reduction in the prevalence of the metabolic syndrome, the two primary outcomes. PROACTIVE is the first behavioural intervention study to assess the effects of physical activity and diet on abdominal obesity and associated metabolic risk factors in a primary healthcare setting, include a generalised sample of men and women and examine long-term (24 months) effects. PROACTIVE has the potential to provide the basis for changing clinical practice (primary care) with respect to the prevention and reduction of obesity and related health risks. The purpose of this report is to present and discuss the rationale, design and methods of PROACTIVE.

Heart rate and exercise intensity during training: observations from the DREW Study.

OBJECTIVE: Cardiovascular drift (CVdrift) is characterised by a continuous, gradual increase in heart rate (HR) after approximately 10 min of moderate-intensity aerobic exercise, despite maintenance of a constant work rate. This has important implications for trials that employ HR to monitor exercise intensity, as reducing work rate in order to keep HR constant could result in participants exercising below the intended intensity. Utilising the Dose Response to Exercise in Women (DREW) database, we sought to determine if increases in HR during exercise (CVdrift) resulted in clinically significant reductions in exercise work rate in order to keep HR within a target range. DESIGN: Randomised, prospective study. SETTING: DREW clinical exercise trail, The Cooper Institute, Dallas, Texas. PARTICIPANTS: Overweight (body mass index 25-43 kg/m2), previously sedentary postmenopausal women (n=326). INTERVENTION: Treadmill and cycling exercise (30-90 min, three to five times per week) at a HR corresponding to 50% of peak oxygen uptake (VO2peak). MAIN OUTCOME MEASURE: Changes in exercise intensity (metabolic equivalents (METS)) during exercise in response to CVdrift. RESULTS: We observed small increases in HR (1-4 beats per minute, p<0.001) combined with small increases in intensity (0.01-0.03 METS, p<0.03) during the combined 12 963 exercise training sessions. Further, we identified only 101 (0.78%) sessions in which intensity was reduced during the course of the exercise session, potentially in response to CVdrift. CONCLUSIONS: We conclude that CVdrift did not contribute to significant reductions in exercise intensity in the DREW study.

Retention rates and weight loss in a commercial weight loss program.

OBJECTIVE: To evaluate and describe retention rates and weight loss in clients participating in a commercial weight loss program. SUBJECTS: A total of 60 164 men and women ages 18-79 years who enrolled in the Jenny Craig Platinum program between May 2001 and May 2002. METHODS: Retention rates, mean weight loss and percent weight loss were calculated on a weekly basis for the 52-week period following initial enrollment in the weight loss program. Clients were categorized based on final week of participation in the program (weeks 1-4, weeks 5-13, weeks 14-26, weeks 27-39 and weeks 40-52) and weight loss was calculated at final week. A subgroup of clients was identified based on attendance through 13, 26 and 52 weeks. Mean and percent weight loss was calculated for these subgroups of clients. RESULTS: Of the 60 164 men and women who enrolled in the weight loss program, 73% were retained in the program after 4 weeks, 42% at 13 weeks, 22% at 26 weeks and 6.6% at 52 weeks. Clients who dropped out of the program during the first 4 weeks lost 1.1+/-1.6% (mean+/-s.d.) of their initial body weight, whereas clients who dropped out between 40 and 52 weeks lost 12.0+/-7.2%. Clients in the 13-week, 26-week and 52-week cohorts lost 8.3+/-3.3, 12.6+/-5.1 and 15.6+/-7.5% of their initial body weight, respectively. CONCLUSION: Weight loss was greater among clients who were retained in the program longer. The findings from this study suggest that a commercial weight loss program can be an effective weight loss tool for individuals who remain active in the program.