ORIGINAL ARTICLE A physical activity program to reinforce weight ...

International Journal of Obesity (2006) 30, 697–703 & 2006 Nature Publishing Group All rights reserved 0307-0565/06 $30.00 www.nature.com/ijo

ORIGINAL ARTICLE A physical activity program to reinforce weight maintenance following a behavior program in overweight/obese subjects N Villanova, F Pasqui, S Burzacchini, G Forlani, R Manini, A Suppini, N Melchionda and G Marchesini Department Internal Medicine and Gastroenterology, Unit of Metabolic Diseases, ‘Alma Mater Studiorum’ University of Bologna, Bologna, Italy Objective: To investigate the effects of a specific program to implement physical activity (fitness program) on weight loss maintenance, activity level and resting energy expenditure (REE). Design: Observational study of subjects completing a behavioral program. Subjects: In total, 200 overweight/obese subjects (36 males, aged 20–66 years; average BMI, 35.2 kg/m2). Program and measurements: The fitness program consisted of 12 bimonthly sessions, chaired by doctors and dietitians, involving groups of 8–12 subjects. Patients entered the program approximately 9 months after the end of behavioral treatment, during a weight loss maintenance period. The goal was set at a light-to-moderate daily physical activity (brisk walking), quantitatively measured by a pedometer; REE was measured before and after the fitness program by indirect calorimetry in a subset of patients. Results: The fitness program restarted the process of weight loss in over 60% of subjects. At the end of the study, 84% of patients walked at least 5000 steps per day, compared with 24% at the beginning of the study. The probability of losing from 5 to 10% of initial body weight increased by 20% for any 1000 steps/day (OR, 1.20; 95% CI (confidence interval), 1.07–1.35), and that of losing more than 10% by over 30% (OR, 1.33; 95% CI, 1.19–1.49). REE increased significantly by 100 kcal/day ( þ 7.5%), in spite of further weight loss (1.8%). Conclusion: A specific fitness program in the weight maintenance phase after a behavioral program may significantly improve the long-term control of obesity. International Journal of Obesity (2006) 30, 697–703. doi:10.1038/sj.ijo.0803185; published online 29 November 2005 Keywords: behavior therapy; indirect calorimetry; pedometer; physical fitness; weight loss maintenance; metabolic syndrome

Introduction Lifestyle and behavioral factors are the cornerstones in the prevention and treatment of obesity.1 Improving the efficacy of weight-reducing programs is a specific challenge for obesity centers. Weight loss is relatively easy to obtain by calorie restriction, but the long-term effects of dieting alone are deleterious on both lean body mass2 and resting energy expenditure (REE), which is reduced by as much as 30%.3

Correspondence: Professor G Marchesini, Department Internal Medicine and Gastroenterology, Unit of Metabolic Diseases, ‘Alma Mater Studiorum’, University of Bologna, Policlinico S. Orsola, Via Massarenti 9, I-40138 Bologna, Italy. E-mail: [email protected] Received 25 May 2005; revised 30 August 2005; accepted 16 September 2005; published online 29 November 2005

This contributes to difficulties in weight loss maintenance; the majority of patients completely regain weight over 3 years, and only a subgroup maintains initial weight loss over a 4-year period.4,5 Physical activity has been advocated as a key behavioral component in the prevention of weight regain.1,6 It improves long-term weight loss maintenance both by increasing lean body mass and by promoting total energy expenditure.7 The focus of research and recommendations on physical activity has long been on vigorous, programmed exercise, such as jogging, swimming, or sports participation.8,9 Although the relationship between the intensity of physical activity and weight loss or weight loss maintenance has never been clarified,10–12 more recent guidelines emphasize the beneficial effects of shorter bouts of moderate-intensity physical exercise within everyday activities.13 Light-intensity activities are more likely to be long-lasting14 and much easier

Fitness program in obesity N Villanova et al

698 overweight range (body mass index (BMI), 25–29.9 kg/m2), 37% in Class I obesity (BMI, 30–34.9 kg/m2), 32% in Class II (BMI, 35–39.9 kg/m2) and 16% in class III (BMI, X40 kg/m2). Their clinical data are reported in Table 1. We aimed to test the effectiveness of the fitness program as part of a routine clinical practice. Based on our previous experience, a progressive increase in body weight was expected following CBT;17 therefore, also weight loss maintenance might be considered a positive result. As a pilot investigation, we opted for an observational study, and patients signed an informed consent for entering the fitness program and for allowing data recording. The whole study was approved by the senior staff committee of our Department, a board comparable to an Institutional Review Board.

to integrate in daily routine. However, they are difficult to monitor because of the varying contexts of ordinary daily functions. A pedometer may help to give a quantitative estimate in a free-living population, as well as to increase motivation to initiate and to maintain walking as a regular activity.15,16 A program of cognitive-behavioral therapy (CBT) for obesity has been operative in our unit since 1992.17 Based on the LEARN program for weight control,18 it includes a few notions on physical activity, but the compliance of patients to exercise has never been systematically tested. More recently, we developed a new program to stimulate further physical activity in subjects completing the LEARN course. This new program, referred to as ‘fitness program’, is offered to subjects completing CBT after a period of practice with weight loss maintenance. The aim of the present study has been to assess the cumulative effects of the combination of the two programs on regular activity and weight loss maintenance in treatment-seeking obese subjects. Primary outcome measures were the weight history, the amount of daily physical activity and the REE. The prevalence of comorbidities of the metabolic syndrome was registered as secondary outcome.19

Cognitive-behavioral therapy (CBT program) Our CBT program is based on the LEARN program for weight control.18 It includes 12 weekly sessions, chaired by doctors and dietitians, involving groups of 8–12 patients. They are taught about BMI and regular weight control and are instructed on counting calories and monitoring daily food intake, with the use of a residential manual. The first two sessions are on behavioral strategies for stimulus control and to establish a pattern of regular eating. Patients are not given a dietary prescription, but are invited to build up their personal diet day by day. Towards the end of each session, patients are given homework assignment to monitor daily eating. All sessions begin by reviewing the monitoring sheets completed during the preceding week. Patients with binge eating traits (high values of the Binge Eating Scale20 and/or positive at the Eating Disorder Examination21) enter the LEARN program after a specific treatment, based on Fairburn’s program.22 This treatment is carried out during eight sessions, chaired by a psychologist trained in eating behavior disorders, which focus on identifying high-risk situations responsible for binge eating and regaining control to re-

Materials and methods Patients We report the results of a pilot study carried out in 200 obese and overweight subjects (164 females; age, 467s.d. (standard deviation) 11 years; range, 20–66), who were enrolled in the fitness program after completion of the CBT program. They were part of a larger group of 257 patients (206 females); 57 patients did not complete the fitness program, with 80% of dropouts losing contact with the obesity center within the first four sessions. Among the 200 patients, 15% were in the

Table 1

Clinical data of the obese population under study (median and range or prevalence and 95% confidence interval) Males (n ¼ 36)

Females (n ¼ 164)

Weight class Overweight (%) Obesity Class I (%) Obesity Class II (%) Obesity Class III (%)

15.2 36.4 30.3 18.2

(5.7–29.1) (21.0–51.9) (16.2–45.8) (7.6–32.7)

20.1 36.4 30.5 14.9

(14.3–26.8) (27.1–41.9) (23.5–37.9) (9.9–21.0)

Waist circumference (cm) Hip circumference (cm) Waist-to-hip ratio Large waist circumference (%)a Raised glucose or treated for diabetes (%)a Raised arterial pressure or treated for hypertension (%)a Low HDL-cholesterol (%)a Raised triglycerides or fibrate treated (%)a Metabolic syndrome (%)b

117 117 1.02 84.8 18.5 54.1 46.2 61.5 65.4

(92–157) (96–198) (0.92–1.14) (67.3–92.4) (7.0–34.6) (37.1–67.8) (27.1–62.8) (40.7–76.0) (44.4–79.1)

100 117 0.84 81.6 13.0 44.2 60.3 26.4 38.9

(76–143) (98–163) (0.68–1.09) (74.3–86.7) (7.8–19.6) (35.5–51.5) (50.8–68.4) (19.0–34.5) (30.0–47.7)

a

0.904

Categorized according to ATPIII criteria.19 bPrevalence of subjects fulfilling three or more criteria of the ATPIII proposal.19

International Journal of Obesity

P-value

o0.0001 0.115 o0.0001 0.804 0.539 0.365 0.196 0.010 0.017


699 establish a pattern of regular eating, on problem-solving skills, on identifying and coping with dysfunctional cognition, on maintaining improvements and preventing relapse. Total treatment lasts 3–5 months, depending on the presence/absence of binge eating, and is followed by three follow-up control visits (1, 3 and 6 months after the end of LEARN).

Fitness program The fitness program includes 12 bimonthly sessions, chaired by doctors and dietitians, involving groups of 8–12 patients. Patients enter the physical activity program approximately 9 months after the end of CBT. The strategy to increase physical activity is focused on the two central aspects of motivation and self-efficacy, integrated with pleasure, social support and removal of barriers. In the initial motivational session, we provide clear information about the benefits of physical exercise on obesity and weight loss maintenance. During the second meeting, the patients review their weight course and discuss the barriers to physical activity they met during the previous months. Special emphasis is given to an individual choice of aerobic activities among the most appealing and most accessible to obese patients. Self-efficacy is favored by educating patients to set physical activity goals that can reasonably be attained and reinforcing the progressive achievement of results. The program also includes specific sessions to stimulate the participants to solve questions, using brain-storming and problem-solving techniques, in agreement with the recommendations of the Task Force on Community Preventive Services.23 To improve compliance, we assess patients’ expectations, provide feedback of any progress and use prompts and rewards. The advantages of social support are also acknowledged, and patients are stimulated to involve family members in the treatment process. Activity options vary from low-intensity lifestyle activities (e.g. gardening, light housework), to nonweight-bearing activities (e.g. swimming, water aerobics, stretching) and particularly to walking, which is indicated as the preferred option. The initial goal is set at lifestyle walking or walking for exercise (brisk walking) for at least 10–15 min three to five times per week. By the end of the program, all patients should attain the target of 30-min brisk walking per day. All these strategies are organized by supplying patients with a guided self-help manual, a logbook and a pedometer. Sessions are chaired by psychologists trained in motivation and implementation of physical activity. Patients are asked to monitor their daily activity, and all sessions begin by reviewing the monitoring sheets completed during the preceding weeks.

Anthropometric and activity measurements Body weight was measured in light clothing and without shoes to the nearest half-kilogram at the beginning of the

program and every other week. Height was measured to the nearest half centimeter. Waist circumference was measured at the nearest half centimeter at the shortest point below the lower rib margin and the iliac crest, whereas hip circumference was similarly obtained at the widest point between hip and buttock. An electronic pedometer was used for the quantitative measure of physical activity (Yamax DIGI Sport Instruments, model SW-200, Yamasa Corporation, Tokyo). Three measurements were recorded for statistical purposes: (a) within 1 month from the beginning of the LEARN program; (b) at the beginning and (c) at the end of the specific program of physical activity. Patients were invited to wear the pedometer during the whole day, and to register the final number of steps at bedtime. For each measurement, we considered the average of a weekly recording. Blood pressure measurements were obtained according to Guidelines of the International Society of Hypertension.24 Three blood pressure readings were obtained at 1-min intervals, and the second and third systolic and diastolic pressure readings were averaged and used in the analyses. Blood glucose, total cholesterol, HDL-cholesterol and triglycerides were measured by common standard laboratory techniques (CHOL, HDL-C plus (2nd generation) and TG assays; Roche Diagnostics Co, Indianapolis, IN, USA). The presence of the metabolic syndrome was assessed according to the criteria set by the Expert Panel on Detection Evaluation and Treatment of High Blood Cholesterol in Adults.19

Resting metabolic rate (REE) In a subgroup of 61 patients, REE was measured under standard conditions at 0800, after a restful night’s sleep (X8 h), by a computerized, open-circuit, indirect calorimetry system (SensorMedics Vmax 29, SensorMedics Co, Yorba Linda, CA, USA), calibrated before each REE test. Subjects consumed no food or beverages other than water after dinner at 1800 on the previous evening, and had not performed any exercise during the last 48 h prior to testing. Before measurements, they were at complete rest in a semirecumbent position for 30 min. The room temperature was maintained at 23711C. Each subject was transported to hospital by a motor vehicle, and was instructed to remain as quiet as possible before and throughout the entire REE measurement period. The room was darkened and noise was kept to a minimum.

Statistical analysis All analyses were carried out on a personal computer and StatView 5.0t program (SAS Institute Inc., Cary, NC, USA). Data are presented as mean7s.d. or as median and range. Prevalence data are given as percentage (95% confidence interval (CI)). Differences between groups were analyzed by Student’s t-test for paired or unpaired data, whenever International Journal of Obesity


700 appropriate, and time group, repeated measurements analysis of variance (ANOVA). Three sets of variables were simultaneously tested: anthropometric data, weight history, energy expenditure. Accordingly, the limit of significance was adjusted according to Duncan’s multiple range25 to pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi P 0 ¼ 1 ðn1Þ ð1 PÞ, where P ¼ 0.05 and n ¼ 3. The final critical value of significance was therefore set at 0.025.

approach, only one-third of subjects failed to lose weight to a specific target of 5% (37%; 95% CI, 30–44), 23% of cases lost from 5 to 10% of their initial body weight (95% CI, 17– 29), and 40% (95% CI, 33–47) had a percentage decrease in body weight exceeding 10% of initial weight. At 1-year follow-up (nearly 3 years since the beginning of the weight reducing program), no significant weight regain was observed in subjects who completed the observation period ( þ 0.8 kg; P vs end of fitness program, 0.374; n ¼ 43).

Results Clinical data At baseline, most patients had multiple features of the metabolic syndrome, the most common being raised blood pressure levels (Table 1). Male gender was associated with a larger prevalence of metabolic syndrome. At the end of the CBT and fitness program, the prevalence of the metabolic syndrome dropped in our population from 43.9% (95% CI, 35.6–51.8) to 23.7% (14.0–35.1) (Po0.0001, Fisher’s exact test).

Weight loss The CBT program produced an average weight loss of 6.77s.d. 8.7 kg, corresponding to 6.6% of initial body weight. In particular, 55% of cases had weight loss exceeding 5% of initial body weight (Figure 1), without differences between genders (P ¼ 0.373). During the follow-up, body weight decreased further, but after 6 months more there was a mild but significant weight gain compared to end-of-CBT values ( þ 2.1 kg; Po0.0001). The fitness program restarted the process of weight loss and, by the end of the program, a further 1.4 kg decrease in body weight was observed (P vs pre-fitness weight, ¼ 0.021; paired t-test). In particular, weight balance was negative in 123 out of 200 subjects. By means of the combined

Fitness

CBT

96

Activity level The baseline activity level was generally low (Table 2), with only a quarter of patients above the threshold of 5000 steps per day (more frequently males, 31 vs 21% in females; P ¼ 0.091; Fisher’s exact test). Physical exercise increased in both males and females following the CBT program, on average by over 2000 steps/day (Table 2). During the fitness program, the activity level further increased by nearly 3000 steps/day. On average, our patients doubled the total number of steps per day they used to take at the beginning of the behavior program. By the end of the study, 84% of patients took at least 5000 steps/day, compared with 24% at the beginning. The total number of steps taken increased significantly irrespective of the presence of eating disorders (repeatedmeasures ANOVA, time group; P ¼ 0.350). In subjects with binge eating behavior, the average number of daily steps was 41897s.e. 452 at enrolment, 57687428 at the beginning of the fitness program, 83147582 at the end of the study. In the same group, body weight decreased systematically from 94.572.6 kg at baseline to 89.472.8 and to 87.972.9 (P vs baseline, ¼ 0.0001). Again, no differences were observed compared with subjects without binging (repeated-measures ANOVA, P ¼ 0.949). Total weight loss significantly correlated with the final number of steps/day as well as with the increase in the number of steps from baseline (r2 ¼ 0.220 and 0.165, respectively; Po0.0001), and weight loss increased significantly according to quartiles of final activity level (Figure 2).

Body Weight (kg)

94 92 Table 2 Anthropometric values, number of steps per day and resting energy expenditure in the course of the weight-reducing CBT program and the fitness programs

90 88

Baseline

86 84 82 80 o

5

8

14 20 Months

32

Figure 1 Time course of body weight in overweight/obese subjects entering the specific activity (fitness) program following a program of cognitivebehavioral therapy (CBT). Note that the 1-year follow-up after the fitness program is only available in 43 subjects.


Prefitness

End-of-fitness

85.8716.2b Weight (kg) 93.7717.5 87.4716.1a Body mass index (kg/m2) 35.275.3 32.875.1a 32.175.2b Waist circumference (cm) 102.2712.5 F 97.7712.8b Number of steps/day 3.96372.642 6.08272.818a 8.71773.980b X5000 steps/day (%) 24 (18–30) 72 (66–78) 84 (78–88) Resting energy expenditure F 1.3287219 1.4287289b (kcal/day)c a Significantly different from Baseline; Po0.0001. bSignificantly different from prefitness values; Po0.005. cMeasured in 61 cases. Data are expressed as means7s.d. or as prevalence (95% confidence interval).


701 35 Body Weight Loss (kg)

30 25 20 15 10 5 0 –5 –10 12 8.5-12 Steps per day (Thousands)

Figure 2 ‘Box and whiskers’ representation of body weight loss in the course of the whole program including the cognitive-behavioral treatment followed by the fitness program. Data are related to the final level of physical activity, measured by the average daily number of steps. In this representation, the box comprises the 25–751 percentiles, the horizontal line being the median value, and the whiskers stretches from 10 to 901 percentiles.

In particular, the probability of losing from 5 to 10% of initial body weight increased by 20% for any 1000 steps/day (OR, 1.20; 95% CI, 1.07–1.35; P ¼ 0.02), and that of losing more than 10% of initial body weight increased by over 30% (OR, 1.33; 95% CI, 1.19–1.49; Po0.0001). Also the amount of weight loss during the fitness program correlated with the increase of daily steps during the same program (r2 ¼ 0.208; Po0.0001).

Resting energy expenditure REE was only available in the pre- and post-fitness program time points in 61 subjects. These subjects were perfectly representative of the total population (female gender, 79%; age, 447s.e. 2 years; BMI, 34.975.4 kg/m2; similar glucose, triglycerides, HDL-cholesterol; prebehavior activity, 36447368 steps/day; prefitness activity, 56457437 steps/day). REE increased significantly by 100 kcal/day ( þ 7.5%), in spite of weight loss (1.8%). When related to the theoretical body weight corresponding to BMI of 25 kg/m2, REE increased from 19.873.1 kcal/kg to 21.273.4 (Po0.0001). A significant correlation was observed between the total number of steps per day and the increase in REE (r2 ¼ 0.144; Po0.005).

Discussion This pilot study indicates that a specific fitness program in the weight maintenance phase of a behavior program, significantly improves weight loss, weight loss maintenance and the features of the metabolic syndrome in obese patients. Due to the observational design of the study and the absence of a control group, the above statement needs a

word of caution. Weight changes were not recorded in an identical untreated population and also subjects who dropped out were not systematically followed to allow comparison with treated patients. The beneficial effects of the fitness program are however supported by the wellknown failure to maintain weight loss in obese patients at the end of any weight reducing program.4,5 This was also observed in our subjects at the end of CBT and has been previously reported in an extensive revision of the results attained in our institution.17 The fitness program promoted a further weight loss after CBT, and body weight remained on average stable during a 1-year follow-up in subjects who completed this long-term observation period. Our comprehensive strategy focused on the two central aspects of motivation and self-efficacy, both having a positive role in promoting physical activity. Motivation was particularly oriented to persuade the patients that regular physical activity was the best way to promote permanent weight loss and physical fitness, as well as to prevent and/or to cure the metabolic syndrome. This last issue was a secondary outcome of our study; adherence to a physical activity program significantly reduced the cardiovascular risk profile, in keeping with several studies showing a beneficial effect of exercise on the primary prevention26 and in the treatment27 of the metabolic syndrome. The efficacy, effectiveness and feasibility of counseling for physical activity, at least in primary care settings, is still under debate.23 We chose a rather long intervention program in a specialist care setting in the hope that the more intensive and prolonged is the program for promoting exercise, the more effective it is, even if intensive interventions do not guarantee long-term adherence.28 The percentage of cases that reached a reasonable goal of physical activity was high, but we failed to achieve an optimal level of physical activity in all subjects. Our population volunteered for the fitness program, but we did not screen subjects for readiness to change from a sedentary life;29 failure in a few subjects and the drop-out rate (22%) may thus stem from nonselection. By contrast, a previous history of disordered eating behavior does not seem to determine different responses to the exercise program in our series. Patients entered the fitness program approximately 9 months after the end of the weight-reducing program. The reasons for this delay were only partly due to logistics. The importance of a maintenance program after the end of a weight reducing program has been repeatedly emphasized.30 The strategies for weight loss maintenance require a series of abilities, which are not compatible with attempts to lose additional weight. During this period, subjects are invited to stop calorie counting, but to keep on writing the food intake logbook until no changes in weight occur. Cooper et al.30 suggested that a supervised period of weight maintenance must be followed by a minimum of 6-month additional practice at maintaining a stable weight, before entering any new program. International Journal of Obesity


702 Physical activity is of paramount importance in the maintenance program, and our patients had already increased the number of steps when they entered the specific fitness program. During this period and the whole fitness program the use of an electronic pedometer becomes crucial. The instrument records vertical movements and is useful in estimating lightto-moderate occupational activities, with a few limitations. It only measures movement in one direction; it fails to discriminate between moderate and heavy work and to detect static work. Finally, it is unable to measure movements while cycling31 and has the highest correlation with total energy expenditure when walking is the preferred activity,32 as it was the case in our patient group. Bassett et al.33 reported that an electronic pedometer is accurate to within 0.3% of the actual number of steps walked at 4.8 km/h, and the specific device we used probably underestimates the total number of steps.34 In addition, we systematically underestimated total physical activity in our patients by relying solely on the pedometer, omitting any other source of activity. During the fitness program, the activity of our patients was mainly oriented to increase low-intensity activities such as walking, using the stairs, gardening and so on, with walking accounting for 80% or more of total reported physical activity. The advantage of a pedometer is that, by allowing a reliable, quantitative measure, it provides a well-defined target and increases self-efficacy in compliant patients. Obese patients who successfully maintained at least 5% of initial weight loss after the CBT program over 1 year followup had significantly higher levels of physical activity than patients who did not maintain weight loss or did not lose at least 5% of initial weight. We did not distinguish between low-intensity but prolonged exercise and more intense activities. The key issue for weight control remains to maximize the volume of calorie used (at any intensity), and to combine this with healthy eating. In addition, brisk walking, which is the base of our fitness program, does not require the use of home equipment for exercise, which proved to favor maintenance of weight loss.35 The amount of physical activity necessary to maintain energy balance after weight loss and to keep body weight stable in our weightreduced obesity-prone population seems to be more than 8500 steps/day, the best results being achieved with more than 12 000 steps/day, in keeping with a systematic review.36 It is still under debate whether energy restriction and weight loss may cause a permanent suppression of the REE at any given body composition. There are conflicting data regarding how physical activity affects REE. A few studies showed an elevated REE in endurance-trained as compared to sedentary individuals.37,38 Other studies did not find differences in REE between endurance-trained and sedentary subjects, after correction for lean body mass.39,40 However, exercise must be rather intense and of long duration in order to maintain an elevated REE 1 or 2 days after the exercise,41 when our patients were tested by indirect calorimetry. International Journal of Obesity

Any minimum variation in REE is potentially of great importance. A meta-analysis supports the hypothesis that exercise provides protection against loss of lean body mass during dietary restriction.42 In our patients, we did not measure lean body mass, but indirect calorimetry confirmed that prolonged aerobic exercise prevents the reduction of REE in a dose-dependent manner, being larger in patients where aerobic exercise was more constant and prolonged (12 000 steps/day or more), in spite of significant weight loss. The relationship between REE, the number of steps per day, and weight loss maintenance are also in keeping with the hypothesis that the beneficial effects of the fitness program were not merely due to the continuous care and prolonged contact with therapists. A continuous care model of treatment definitely helps maintaining weight loss is subjects who keep on the contact with the obesity centers,43,44 but in the present series any advantage appears to be somehow related to a change from a sedentary to an active lifestyle. In summary, a specific fitness program may help patients to increase physical activity and to prevent weight regain following a CBT program. Weight loss maintenance may in turn favor the adherence to exercise and to a healthier lifestyle and improve the psychological profile. All these effects must be tested prospectively in randomized trials with long-term follow-up. Our study underlines the importance of long-lasting, structured programs to help obese subjects in the difficult process of behavioral changes and to motivate the adoption of healthier lifestyle, also independently of weight loss.

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