Children's Residential Weight-Loss Programs Can Work: A Prospective Cohort Study of Short-Term Outcomes for Overweight and Obese Children
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《小儿科》
School of Leisure and Sports Studies, Leeds Metropolitan University, Leeds, United Kingdom
Clinical Biochemistry and Immunology, Leeds General Infirmary, Leeds, United Kingdom
Academic Unit of Psychiatry and Behavioural Sciences, Leeds University School of Medicine, Leeds, United Kingdom
ABSTRACT
Objective. The evidence base for child obesity treatment is weak. Children's weight-loss camps, despite their popularity, have not been properly evaluated. This study evaluated the effectiveness of a residential weight-loss camp program for overweight and obese children.
Methods. A total of 185 overweight children (mean age: 13.9 years) enrolled in 1 of 4 consecutive programs between 1999 and 2002 (intervention group) were compared with 94 children of similar ages who were not camp attendees, ie, 38 overweight children and 56 normal-weight children. The intervention group attended a 6-week (maximum) summer residential weight-loss camp. The program included a daily schedule of six 1-hour, skill-based, fun, physical activity sessions, moderate dietary restriction, and group-based educational sessions. All children were assessed for body weight, height, and other anthropometric measures, blood pressure, aerobic fitness, self-esteem, and selected sports skills.
Results. Campers, who stayed for a mean of 29 days, lost 6.0 kg, reduced their BMI by 2.4 units, and reduced their BMI SD scores by 0.28. Fat mass decreased significantly (from 42.7 to 37.1 kg), whereas fat-free mass did not change. In contrast, both comparison groups gained weight during this period. Camp attendees also showed significant improvements in blood pressure, aerobic fitness, and self-esteem. Longer durations of stay were associated with greater improvements in outcomes.
Conclusions. In the short term at least, this weight-loss program was effective across a range of health outcomes. Ongoing research is examining the maintenance of these improvements. Future research should investigate whether benefits can be generalized across weight-loss camps and how the intervention can be adapted to nonresidential, term-time settings.
Key Words: child obesity weight-loss camp physical activity fat mass blood pressure aerobic fitness self-esteem
Child obesity has been described as a "pandemic of the new millennium."1 This reflects the rising worldwide prevalence of obesity among children, the increased risk for adult obesity, and the impact of obesity on physical and psychological health. The magnitude of the health problem can be seen in the costs associated with obesity. Obesity-attributable medical costs in the United States in 2003 were estimated at $75 billion.2 Although the need for effective management and prevention is clear, the evidence to guide their implementation is not.
The updated Cochrane review of child obesity interventions found relatively few randomized, controlled trials with sufficiently long follow-up periods for inclusion in the review process.3 The trials included were heterogeneous in study design, quality, and outcome measures, leading the review authors to state, "no direct conclusions can be drawn from this review with confidence." Others have considered that there is sufficient research evidence to draw up and agree on expert recommendations for child obesity treatment,4 although it is acknowledged that their effectiveness has yet to be tested.5 Despite the divergence of opinion regarding the acceptable quality of evidence, child obesity is managed actively in clinical practice, with management usually centering on the promotion of healthy eating and activity.6
Given the need for effective interventions, it is surprising that children's weight-loss camps have received little attention. Several studies reported on the outcomes of children's summer camps for health problems ranging from diabetes mellitus7 and burn injuries8 to cystic fibrosis.9 Although weight-loss and fitness camps are popular in the United States, we are aware of only 4 studies evaluating their effectiveness. Two found significant reductions in body weight during 8-week camps in the United States,10,11 but a third found no impact of a 4-week day camp on girls' BMI.12 We reported positive psychological outcomes, and associated reductions in body weight, for a residential summer weight-loss camp for children held in the north of England in 2000.13
This report evaluated the short-term outcomes of the first 4 years of this United Kingdom camp, in terms of key measures of anthropometry, physical state, self-esteem, and sports skills. It was hypothesized that there would be improvements from the beginning to the end of the camp in all of these areas.
METHODS
Participants
Two hundred sixty-three children were enrolled in 1 of 4 successive programs during the summer vacations of 1999–2002. Children were recruited from all over the United Kingdom (as well as a few from Europe) through a range of sources, such as self/parental referral, medical referral, or referral from social service or educational organizations. Complete data were obtained for 185 children (82 boys and 103 girls; mean age: 13.9 years; range: 9–18 years) who attended camp for 2 to 6 weeks (mean: 29 ± 11 days). Some children attended the camp on successive years, and only data for their first attendance were included in the analysis. This led to the exclusion of 61 data sets. The study participation rate was 92% (185 of 202 children); reasons for nonparticipation were nonconsent (5 children), failure to complete data collections at the beginning or end of camp (8 children), exclusion from the camp (3 children), or dropout (1 child).
Acceptance into the program was contingent on having a BMI above cutoff values for overweight14 and undergoing health screening performed by the child's family physician. Of the children accepted, 25 (14%) were overweight and 160 (86%) were obese. Parents paid for their children's attendance (￡370 or $700 per week, for a maximum of 6 weeks). However, 20% of children were funded completely by their primary care trust or social services department.
This intervention group was compared with 2 free-living groups, ie, 38 overweight children (29 boys and 9 girls; mean age: 13.6 years) and 56 normal-weight children (26 boys and 30 girls; mean age: 14.2 years). These comparison children were recruited as a convenience sample through local schools and advertisements in the local press in 2000 and 2001. The schools allowed full class groups to be assessed, and we advertised actively for overweight and obese children to form an overweight comparison group. Comparison children engaged in unmonitored summer vacation activities during the time the camp was taking place.
No data were collected on ethnicity or parental employment status for campers or comparison subjects, although the majority of children in both groups were white. Ethical approval was provided by the Leeds (West) local research ethics committee. All children and parents gave their informed written consent.
Measures
Anthropometric Measures
Body mass was measured to the nearest 0.01 kg and height to the nearest 1 cm. BMI values and BMI SD scores were calculated for each participant.15 Waist and hip circumferences were assessed with protocols from the anthropometric standardization manual.16 In addition, the percentage of body fat was assessed with air-displacement plethysmography.17 This method is quick to use, noninvasive, and suitable for assessment of body composition among children.18 In our laboratory, the between-trial coefficient of variation for the percentage of fat for 44 overweight or obese adolescents (BMI: 30.52 ± 5.61 kg/m2) measured twice on the same day was 4.0% (data not shown).
Physical State
Blood pressure was measured with a mercury sphygmomanometer, with diastolic pressure recorded at the fifth phase of Korotkoff sounds (data were collected for only 95 children in 2001 and 2002). An incremental, submaximal, treadmill, walking protocol evaluated aerobic fitness (warm-up: 5 minutes; starting speed: 3 km/hour; increments: 0% gradient with 0.5 km/hour increments each 1 minute for 4 minutes, then 2.5% gradient increments each 1 minute to a maximum of 20%, and then 0.5 km/hour increments to 85% of the child's predicted heart rate maximum). Oxygen uptake at 85% of the child's predicted heart rate maximum was the outcome measure.
Self-Esteem
Self-esteem was assessed with the Self-Perception Profile for Children.19 Each of the subscales has high internal reliability (r = 0.73–0.86) and good 9-month retest reliability (r = 0.8).19 Only scores for the global self-worth scale are reported here.
Sports Skills
Selected skills were evaluated in the intervention group only. Each child was given 1 minute to score as many points as possible in each of the following tasks: badminton serve,20 basketball shot,21 soccer dribble,22 and volleyball volley.23 We did not carry out any test of reliability, although researchers reported high test-retest reliability for these tests (r = 0.80–0.98).
Program and Procedure
All children who attended the camp were residents in boarding school premises, which provided catering, residential, educational, and high-quality indoor and outdoor sports facilities. All staff members were housed on site throughout the summer period. The program aim was to provide a safe supportive environment where children could reduce their body mass while having fun. In addition, a child-centered approach was used that focused on providing children with positive experiences and appropriate strategies they could continue to use after returning home.
Children were divided into 4 groups, according to age and gender (9- to 14- and 15- to 18-year-old girls and boys), for all aspects of the camp program. The daily schedule of physical activity combined a range of structured, fun-type, skill-based activities, with six 1-hour sessions each day, ie, 1 aerobic session (eg, dance or aerobics), 1 water-based session (eg, canoeing or swimming), 2 student-choice sessions, and 2 games-based sessions (eg, netball or rugby). The aims of the physical activity sessions were to develop skills and competence in a range of activities, with enjoyment and choice being fundamental components of this educational process. All activities were led by physical education teachers and qualified sports coaches.
There was moderate dietary restriction. Energy intake was based on an approximation of basal metabolic rate (5460–13860 kJ/day), with the equations of Schofield,24 and energy was provided as 3 meals and 1 snack each day. Meals (55% of total energy intake as carbohydrate, 30% as fat, and 15% as protein) were designed to be similar to the food to which children would be exposed in their home environment (including foods such as salad, pasta, and pizza). Children were provided with meat and vegetarian options at each meal, and the 14-day menu was rotated every 2 weeks. Opportunities to obtain food outside the camp were extremely limited, given the location (a 20-minute walk to the local store and 24-hour security monitoring at the site). In addition, families were encouraged to help their children adhere to the camp diet by not bringing or sending food to the camp.
Children also took part in 4 educational sessions per week, conducted by the education team at the camp. These covered issues such as changing food choices, maintaining behavior change, and addressing bullying.
Body mass and sports skills were recorded weekly. Height, percentage of body fat, aerobic fitness, other anthropometric measures, blood pressure, and global self-worth scores were recorded at the start and end of the program. All assessments were made by the same personnel. Comparison participants were assessed 1 to 2 weeks before and after each camp session.
Statistical Analyses
One-way analyses of variance tested for group differences at baseline (with Scheffé posthoc comparisons). Multivariate analysis of covariance was used, with the group entered as the dependent variable and the baseline values and duration entered as covariates. Two-way analyses of variance (main effects of group and time) with the main outcome measures and paired t tests with Bonferroni adjustments were used to test the significance of changes from the beginning to the end of camp. Changes in sports skills were assessed with Wilcoxon tests. No significant differences in baseline variables or in the degree of weight change were found among the 4 cohorts of campers. Therefore, data were combined into single groups for the intervention and comparison groups.
RESULTS
At the start of the program, campers differed significantly from both comparison groups in nearly every anthropometric measure (Table 1). They had greater body mass, BMI, BMI SD scores, percentages of body fat, fat mass, and waist and hip circumferences [smallest F(2,276) = 61.72; P < .001]. In addition, the campers had greater fat-free mass than normal-weight comparison children but not overweight comparison children.
Multivariate analysis of covariance revealed significant between group differences across all measures [smallest F(2,244) = 8.61; P < .001]. Significant group-time interactions showed that campers reduced their body mass, decreased their BMI SD scores, lost body fat, and reduced both waist and hip circumferences [smallest F(2,244) = 28.87; P < .001]. The reduction in body mass was attributable primarily to a reduction in fat mass (86% of the change in body mass). In contrast, the 2 comparison groups showed significant increases in many of these measures. Figure 1 shows the distribution of changes in BMI SD values for the camp attendees. No child increased their BMI and nearly 80% (n = 148) reduced their BMI between 1.0 and 3.4 units.
Changes in measured aerobic fitness are presented in Table 2. Significant group-time interactions were found for aerobic fitness changes [F(2,204) = 8.97; P < .001]. These improvements in fitness were accompanied by significant reductions in both systolic blood pressure [F(2,128) = 6.02; P = .003] and diastolic blood pressure [F(2,128) = 14.9; P < .001].
There was a significant baseline difference in self-esteem, with the campers scoring lower than the normal-weight comparison children but not the overweight comparison children [F(2,219) = 27.94; P < .001]. There was also a significant group-time interaction [F(2,213) = 4.15; P = .012] showing that campers improved in self-esteem, whereas there was no change in the other 2 groups. With respect to sports skills, there were significant (P < .05) improvements in all measures (badminton serve: 30–50 points; basketball shot: 7–13 points; soccer dribbling: 5–7 points; volleyball volley: 15–27 points).
Duration of stay was significantly (P < .01) associated with changes in a range of variables (body weight: r = –0.69 [n = 185]; BMI: r = –0.76; BMI SD score: r = –0.58; percentage of body fat: r = –0.16; fat mass: r = –0.39; waist circumference: r = –0.60; hip circumference: r = –0.31; oxygen uptake: r = –0.20). All of these correlations showed that, the longer the stay at camp, the greater was improvement in these measures.
DISCUSSION
The evidence described above shows that residential summer weight-loss camps can be effective across a range of outcomes. On average, campers lost 6 kg, reduced their BMI by 2.4 units, and reduced their BMI SD score by 0.28. The majority of this reduction in body mass was achieved through a reduction in fat mass and was detectable in measures of waist and hip circumferences. The benefits of camp participation were also seen in blood pressure, aerobic fitness, self-esteem, and improved sports skills. Importantly, these benefits were specific to camp participation, because overweight and normal-weight comparison children increased their body weight and fat mass but showed little change in other measures during this period.
The therapeutic gains reported here are better than most reported over the course of child obesity interventions, in terms of body mass change,25,26 fitness,27 or blood pressure.28 Although there were individual variations in responses, no children increased their BMI and 80% reduced it by at least 1 BMI unit in a period of 4 weeks. Not surprisingly, longer durations of stay were associated with greater improvements in body mass reduction and aerobic fitness.
Because it was a multicomponent program, it is not possible to identify the most effective parts of the intervention. Increasing physical activity and reducing sedentary behaviors and intakes of high-fat, energy-dense foods are at the heart of expert recommendations and were cornerstones of the camp program. However, their success in achieving and maintaining a negative energy balance may be highly dependent on nonspecific factors, such as the social environment of the camp and its residential nature. Such factors may assist children in overcoming the body-related and social barriers to physical activity that are characteristic of children who attend summer fitness camps.29 Overall, providing a controlled but safe, enjoyable, and social environment is a likely major contributor to the changes described above.
Whether these improvements persist when children leave camp is not addressed in the present report. For many involved in child obesity management, this is a critical indicator of success. We make 2 points on this issue. First, it is necessary for any treatment program to demonstrate short-term effectiveness. This is the focus of the present article. Second, we are using quantitative and qualitative approaches to evaluate aspects of follow-up care and maintenance of treatment effects. These data are forthcoming.
A major limitation of this research is the study design. This was not a randomized controlled trial, something not possible given the financial, organizational, and ethical constraints of the program. Rather, it was an evaluation of whether 4 successive cohorts of children benefited from a nonprofit, weight reduction intervention. By including data for 2 comparison groups of children, the study represents an appropriate design for the treatment offered. Additional limitations include the camp program itself. In the present format, weight-loss or fitness camps can be organized only during extended school vacation periods. They are limited in size, have a demanding staff/student ratio, and appear expensive. However, the cost should be contrasted with the cost of maintaining a child at home during the summer holidays and the costs of the short- and long-term consequences of obesity.
Finally, there is a question regarding generalizability. The benefits observed in this study may not be reproduced in other weight-loss camps. Differences in program structure and content, environment, participant backgrounds, and expectations may affect outcomes. Additional research is needed to address this and to investigate whether the intervention can be adapted to a nonresidential setting or delivered during the school term. Despite these cautions, these multiple short-term benefits suggest that camps such as this represent a valuable practical treatment option for overweight and obese children.
ACKNOWLEDGMENTS
This research was supported by a grant from the National Heart Research Fund (Leeds, United Kingdom).
FOOTNOTES
Accepted Oct 25, 2004.
No conflict of interest declared.
REFERENCES
Kimm SYS, Obarzanek E. Childhood obesity: a new pandemic of the new millennium. Pediatrics.2002; 110 :1003 –1007
Finkelstein EA, Fiebelkorn IC, Wand G. State-level estimates of annual medical expenditures attributable to obesity. Obes Res.2004; 12 :18 –24
Summerbell CD, Ashton V, Campbell KJ, Edmunds L, Kelly S, Waters E. Interventions for treating obesity in children. Cochrane Database Syst Rev.2003; (3):CD001872
Barlow SE, Dietz WH. Obesity evaluation and treatment: expert committee recommendations. Pediatrics.1998; 102 :29 –33
Barlow SE, Dietz WH. Management of child and adolescent obesity: summary and recommendations based on reports from pediatricians, pediatric nurse practitioners, and registered dietitians. Pediatrics.2002; 110 :236 –238
Barlow SE, Trowbridge FL, Klish WJ, Dietz WH. Treatment of child and adolescent obesity: reports from pediatricians, pediatric nurse practitioners, and registered dietitians. Pediatrics.2002; 100 :229 –235
Schlundt DG, Flannery ME, Davis DL, Kinzer CK, Pichert JW. Evaluation of a multicomponent, behaviorally oriented, problem-based "summer school" program for adolescents with diabetes. Behav Mod.1999; 23 :79 –105
Adams CD, Girolami PA, Joseph KE, Sauvageot SA, Slater H. Use of a token reinforcement system to promote appropriate behavior at a pediatric burn summer camp. J Burn Care Rehabil.2002; 23 :297 –305
Blau H, Mussaffi-Georgy H, Fink G, et al. Effects of an intensive 4-week summer camp on cystic fibrosis: pulmonary function, exercise tolerance, and nutrition. Chest.2002; 121 :1117 –1122
Rohrbacher R. Influence of a special camp programme for obese boys on weight loss, self concept and body image. Res Q.1971; 44 :150 –157
Gately PJ, Cooke CB, Butterly RJ, Knight C, Carroll S. The acute effects of an eight-week diet, exercise and educational camp program on obese children. Pediatr Exerc Sci.2000; 12 :413 –423
Baranowski T, Baranowski JC, Cullen KW, et al. The Fun, Food, and Fitness Project (FFFP): the Baylor GEMS pilot study. Ethn Dis.2003; 13 (suppl 1):30 –39
Walker LL, Gately PJ, Bewick BM, Hill AJ. Children's weight-loss camps: psychological benefit or jeopardy Int J Obes.2003; 27 :748 –754
Cole TJ, Bellizzi MC, Flegal KM, Dietz WH. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ.2000; 320 :1240 –1242
Child Growth Foundation. Cross-Sectional Stature and Weight Reference Curves for the U.K. London, United Kingdom: Child Growth Foundation;1990
Lohman TG, Roche AF, Martorell R. Anthropometric Standardization Reference Manual. Champaign, IL: Human Kinetics;1988
Dempster P, Aitkens S. A new air displacement method for the determination of human body composition. Med Sci Sports Exerc.1995; 27 :1692 –1697
Gately PJ, Radley D, Cooke CB, et al. Comparison of body composition methods in overweight and obese children. J Appl Physiol.2003; 95 :2039 –2046
Harter S. Manual for the Self-Perception Profile for Children. Denver, CO: University of Denver;1985
Scott MG, Carpenter A, French E, Kuhl L. Achievement of examinations in badminton. Res Q.1941; 12 :242 –253
Hopkins DR, Shick J, Plack JJ. Skills Test Manual: Basketball for Boys and Girls. Reston, VA: American Alliance for Health, Physical Education, Recreation, and Dance;1984
Mor D, Christian V. The development of a skill test battery to measure general soccer ability. N C J Health Phys Ed.1979; 15 :30 –39
Kronqvist RA, Brumbach WB. A modification of the Brady volleyball skill test for high school boys. Res Q.1968; 39 :116 –120
Schofield WN. Predicting basal metabolic rate: new standards and review of previous work. Hum Nutr Clin Nutr.1985; 39 (suppl 1):5 –41
Epstein LH, Myers MD. Treatment of pediatric obesity. Pediatrics.1998; 101 :554 –571
Ebbling CB, Rodriguez NR. Effects of exercise combined with diet therapy on protein utilization in obese children. Med Sci Sports Exerc.1999; 31 :378 –385
Gutin B, Cucuzzo N, Islam S, Smith C, Moffatt R, Pargman D. Physical training improves body composition of black obese 7- to 11-year-old girls. Obes Res.1995; 3 :305 –312
Gutin B, Barbeau P, Litaker MS, Ferguson M, Owens S. Heart rate variability in obese children: relations to total body and visceral adiposity, and changes with physical training and detraining. Obes Res.2000; 8 :12 –19
Zabinski MF, Saelens BE, Stein RI, Hayden-Wade HA, Wilfley DE. Overweight children's barriers to and support for physical activity. Obes Res.2003; 11 :238 –246(Paul J. Gately, PhD, Carl)
Clinical Biochemistry and Immunology, Leeds General Infirmary, Leeds, United Kingdom
Academic Unit of Psychiatry and Behavioural Sciences, Leeds University School of Medicine, Leeds, United Kingdom
ABSTRACT
Objective. The evidence base for child obesity treatment is weak. Children's weight-loss camps, despite their popularity, have not been properly evaluated. This study evaluated the effectiveness of a residential weight-loss camp program for overweight and obese children.
Methods. A total of 185 overweight children (mean age: 13.9 years) enrolled in 1 of 4 consecutive programs between 1999 and 2002 (intervention group) were compared with 94 children of similar ages who were not camp attendees, ie, 38 overweight children and 56 normal-weight children. The intervention group attended a 6-week (maximum) summer residential weight-loss camp. The program included a daily schedule of six 1-hour, skill-based, fun, physical activity sessions, moderate dietary restriction, and group-based educational sessions. All children were assessed for body weight, height, and other anthropometric measures, blood pressure, aerobic fitness, self-esteem, and selected sports skills.
Results. Campers, who stayed for a mean of 29 days, lost 6.0 kg, reduced their BMI by 2.4 units, and reduced their BMI SD scores by 0.28. Fat mass decreased significantly (from 42.7 to 37.1 kg), whereas fat-free mass did not change. In contrast, both comparison groups gained weight during this period. Camp attendees also showed significant improvements in blood pressure, aerobic fitness, and self-esteem. Longer durations of stay were associated with greater improvements in outcomes.
Conclusions. In the short term at least, this weight-loss program was effective across a range of health outcomes. Ongoing research is examining the maintenance of these improvements. Future research should investigate whether benefits can be generalized across weight-loss camps and how the intervention can be adapted to nonresidential, term-time settings.
Key Words: child obesity weight-loss camp physical activity fat mass blood pressure aerobic fitness self-esteem
Child obesity has been described as a "pandemic of the new millennium."1 This reflects the rising worldwide prevalence of obesity among children, the increased risk for adult obesity, and the impact of obesity on physical and psychological health. The magnitude of the health problem can be seen in the costs associated with obesity. Obesity-attributable medical costs in the United States in 2003 were estimated at $75 billion.2 Although the need for effective management and prevention is clear, the evidence to guide their implementation is not.
The updated Cochrane review of child obesity interventions found relatively few randomized, controlled trials with sufficiently long follow-up periods for inclusion in the review process.3 The trials included were heterogeneous in study design, quality, and outcome measures, leading the review authors to state, "no direct conclusions can be drawn from this review with confidence." Others have considered that there is sufficient research evidence to draw up and agree on expert recommendations for child obesity treatment,4 although it is acknowledged that their effectiveness has yet to be tested.5 Despite the divergence of opinion regarding the acceptable quality of evidence, child obesity is managed actively in clinical practice, with management usually centering on the promotion of healthy eating and activity.6
Given the need for effective interventions, it is surprising that children's weight-loss camps have received little attention. Several studies reported on the outcomes of children's summer camps for health problems ranging from diabetes mellitus7 and burn injuries8 to cystic fibrosis.9 Although weight-loss and fitness camps are popular in the United States, we are aware of only 4 studies evaluating their effectiveness. Two found significant reductions in body weight during 8-week camps in the United States,10,11 but a third found no impact of a 4-week day camp on girls' BMI.12 We reported positive psychological outcomes, and associated reductions in body weight, for a residential summer weight-loss camp for children held in the north of England in 2000.13
This report evaluated the short-term outcomes of the first 4 years of this United Kingdom camp, in terms of key measures of anthropometry, physical state, self-esteem, and sports skills. It was hypothesized that there would be improvements from the beginning to the end of the camp in all of these areas.
METHODS
Participants
Two hundred sixty-three children were enrolled in 1 of 4 successive programs during the summer vacations of 1999–2002. Children were recruited from all over the United Kingdom (as well as a few from Europe) through a range of sources, such as self/parental referral, medical referral, or referral from social service or educational organizations. Complete data were obtained for 185 children (82 boys and 103 girls; mean age: 13.9 years; range: 9–18 years) who attended camp for 2 to 6 weeks (mean: 29 ± 11 days). Some children attended the camp on successive years, and only data for their first attendance were included in the analysis. This led to the exclusion of 61 data sets. The study participation rate was 92% (185 of 202 children); reasons for nonparticipation were nonconsent (5 children), failure to complete data collections at the beginning or end of camp (8 children), exclusion from the camp (3 children), or dropout (1 child).
Acceptance into the program was contingent on having a BMI above cutoff values for overweight14 and undergoing health screening performed by the child's family physician. Of the children accepted, 25 (14%) were overweight and 160 (86%) were obese. Parents paid for their children's attendance (￡370 or $700 per week, for a maximum of 6 weeks). However, 20% of children were funded completely by their primary care trust or social services department.
This intervention group was compared with 2 free-living groups, ie, 38 overweight children (29 boys and 9 girls; mean age: 13.6 years) and 56 normal-weight children (26 boys and 30 girls; mean age: 14.2 years). These comparison children were recruited as a convenience sample through local schools and advertisements in the local press in 2000 and 2001. The schools allowed full class groups to be assessed, and we advertised actively for overweight and obese children to form an overweight comparison group. Comparison children engaged in unmonitored summer vacation activities during the time the camp was taking place.
No data were collected on ethnicity or parental employment status for campers or comparison subjects, although the majority of children in both groups were white. Ethical approval was provided by the Leeds (West) local research ethics committee. All children and parents gave their informed written consent.
Measures
Anthropometric Measures
Body mass was measured to the nearest 0.01 kg and height to the nearest 1 cm. BMI values and BMI SD scores were calculated for each participant.15 Waist and hip circumferences were assessed with protocols from the anthropometric standardization manual.16 In addition, the percentage of body fat was assessed with air-displacement plethysmography.17 This method is quick to use, noninvasive, and suitable for assessment of body composition among children.18 In our laboratory, the between-trial coefficient of variation for the percentage of fat for 44 overweight or obese adolescents (BMI: 30.52 ± 5.61 kg/m2) measured twice on the same day was 4.0% (data not shown).
Physical State
Blood pressure was measured with a mercury sphygmomanometer, with diastolic pressure recorded at the fifth phase of Korotkoff sounds (data were collected for only 95 children in 2001 and 2002). An incremental, submaximal, treadmill, walking protocol evaluated aerobic fitness (warm-up: 5 minutes; starting speed: 3 km/hour; increments: 0% gradient with 0.5 km/hour increments each 1 minute for 4 minutes, then 2.5% gradient increments each 1 minute to a maximum of 20%, and then 0.5 km/hour increments to 85% of the child's predicted heart rate maximum). Oxygen uptake at 85% of the child's predicted heart rate maximum was the outcome measure.
Self-Esteem
Self-esteem was assessed with the Self-Perception Profile for Children.19 Each of the subscales has high internal reliability (r = 0.73–0.86) and good 9-month retest reliability (r = 0.8).19 Only scores for the global self-worth scale are reported here.
Sports Skills
Selected skills were evaluated in the intervention group only. Each child was given 1 minute to score as many points as possible in each of the following tasks: badminton serve,20 basketball shot,21 soccer dribble,22 and volleyball volley.23 We did not carry out any test of reliability, although researchers reported high test-retest reliability for these tests (r = 0.80–0.98).
Program and Procedure
All children who attended the camp were residents in boarding school premises, which provided catering, residential, educational, and high-quality indoor and outdoor sports facilities. All staff members were housed on site throughout the summer period. The program aim was to provide a safe supportive environment where children could reduce their body mass while having fun. In addition, a child-centered approach was used that focused on providing children with positive experiences and appropriate strategies they could continue to use after returning home.
Children were divided into 4 groups, according to age and gender (9- to 14- and 15- to 18-year-old girls and boys), for all aspects of the camp program. The daily schedule of physical activity combined a range of structured, fun-type, skill-based activities, with six 1-hour sessions each day, ie, 1 aerobic session (eg, dance or aerobics), 1 water-based session (eg, canoeing or swimming), 2 student-choice sessions, and 2 games-based sessions (eg, netball or rugby). The aims of the physical activity sessions were to develop skills and competence in a range of activities, with enjoyment and choice being fundamental components of this educational process. All activities were led by physical education teachers and qualified sports coaches.
There was moderate dietary restriction. Energy intake was based on an approximation of basal metabolic rate (5460–13860 kJ/day), with the equations of Schofield,24 and energy was provided as 3 meals and 1 snack each day. Meals (55% of total energy intake as carbohydrate, 30% as fat, and 15% as protein) were designed to be similar to the food to which children would be exposed in their home environment (including foods such as salad, pasta, and pizza). Children were provided with meat and vegetarian options at each meal, and the 14-day menu was rotated every 2 weeks. Opportunities to obtain food outside the camp were extremely limited, given the location (a 20-minute walk to the local store and 24-hour security monitoring at the site). In addition, families were encouraged to help their children adhere to the camp diet by not bringing or sending food to the camp.
Children also took part in 4 educational sessions per week, conducted by the education team at the camp. These covered issues such as changing food choices, maintaining behavior change, and addressing bullying.
Body mass and sports skills were recorded weekly. Height, percentage of body fat, aerobic fitness, other anthropometric measures, blood pressure, and global self-worth scores were recorded at the start and end of the program. All assessments were made by the same personnel. Comparison participants were assessed 1 to 2 weeks before and after each camp session.
Statistical Analyses
One-way analyses of variance tested for group differences at baseline (with Scheffé posthoc comparisons). Multivariate analysis of covariance was used, with the group entered as the dependent variable and the baseline values and duration entered as covariates. Two-way analyses of variance (main effects of group and time) with the main outcome measures and paired t tests with Bonferroni adjustments were used to test the significance of changes from the beginning to the end of camp. Changes in sports skills were assessed with Wilcoxon tests. No significant differences in baseline variables or in the degree of weight change were found among the 4 cohorts of campers. Therefore, data were combined into single groups for the intervention and comparison groups.
RESULTS
At the start of the program, campers differed significantly from both comparison groups in nearly every anthropometric measure (Table 1). They had greater body mass, BMI, BMI SD scores, percentages of body fat, fat mass, and waist and hip circumferences [smallest F(2,276) = 61.72; P < .001]. In addition, the campers had greater fat-free mass than normal-weight comparison children but not overweight comparison children.
Multivariate analysis of covariance revealed significant between group differences across all measures [smallest F(2,244) = 8.61; P < .001]. Significant group-time interactions showed that campers reduced their body mass, decreased their BMI SD scores, lost body fat, and reduced both waist and hip circumferences [smallest F(2,244) = 28.87; P < .001]. The reduction in body mass was attributable primarily to a reduction in fat mass (86% of the change in body mass). In contrast, the 2 comparison groups showed significant increases in many of these measures. Figure 1 shows the distribution of changes in BMI SD values for the camp attendees. No child increased their BMI and nearly 80% (n = 148) reduced their BMI between 1.0 and 3.4 units.
Changes in measured aerobic fitness are presented in Table 2. Significant group-time interactions were found for aerobic fitness changes [F(2,204) = 8.97; P < .001]. These improvements in fitness were accompanied by significant reductions in both systolic blood pressure [F(2,128) = 6.02; P = .003] and diastolic blood pressure [F(2,128) = 14.9; P < .001].
There was a significant baseline difference in self-esteem, with the campers scoring lower than the normal-weight comparison children but not the overweight comparison children [F(2,219) = 27.94; P < .001]. There was also a significant group-time interaction [F(2,213) = 4.15; P = .012] showing that campers improved in self-esteem, whereas there was no change in the other 2 groups. With respect to sports skills, there were significant (P < .05) improvements in all measures (badminton serve: 30–50 points; basketball shot: 7–13 points; soccer dribbling: 5–7 points; volleyball volley: 15–27 points).
Duration of stay was significantly (P < .01) associated with changes in a range of variables (body weight: r = –0.69 [n = 185]; BMI: r = –0.76; BMI SD score: r = –0.58; percentage of body fat: r = –0.16; fat mass: r = –0.39; waist circumference: r = –0.60; hip circumference: r = –0.31; oxygen uptake: r = –0.20). All of these correlations showed that, the longer the stay at camp, the greater was improvement in these measures.
DISCUSSION
The evidence described above shows that residential summer weight-loss camps can be effective across a range of outcomes. On average, campers lost 6 kg, reduced their BMI by 2.4 units, and reduced their BMI SD score by 0.28. The majority of this reduction in body mass was achieved through a reduction in fat mass and was detectable in measures of waist and hip circumferences. The benefits of camp participation were also seen in blood pressure, aerobic fitness, self-esteem, and improved sports skills. Importantly, these benefits were specific to camp participation, because overweight and normal-weight comparison children increased their body weight and fat mass but showed little change in other measures during this period.
The therapeutic gains reported here are better than most reported over the course of child obesity interventions, in terms of body mass change,25,26 fitness,27 or blood pressure.28 Although there were individual variations in responses, no children increased their BMI and 80% reduced it by at least 1 BMI unit in a period of 4 weeks. Not surprisingly, longer durations of stay were associated with greater improvements in body mass reduction and aerobic fitness.
Because it was a multicomponent program, it is not possible to identify the most effective parts of the intervention. Increasing physical activity and reducing sedentary behaviors and intakes of high-fat, energy-dense foods are at the heart of expert recommendations and were cornerstones of the camp program. However, their success in achieving and maintaining a negative energy balance may be highly dependent on nonspecific factors, such as the social environment of the camp and its residential nature. Such factors may assist children in overcoming the body-related and social barriers to physical activity that are characteristic of children who attend summer fitness camps.29 Overall, providing a controlled but safe, enjoyable, and social environment is a likely major contributor to the changes described above.
Whether these improvements persist when children leave camp is not addressed in the present report. For many involved in child obesity management, this is a critical indicator of success. We make 2 points on this issue. First, it is necessary for any treatment program to demonstrate short-term effectiveness. This is the focus of the present article. Second, we are using quantitative and qualitative approaches to evaluate aspects of follow-up care and maintenance of treatment effects. These data are forthcoming.
A major limitation of this research is the study design. This was not a randomized controlled trial, something not possible given the financial, organizational, and ethical constraints of the program. Rather, it was an evaluation of whether 4 successive cohorts of children benefited from a nonprofit, weight reduction intervention. By including data for 2 comparison groups of children, the study represents an appropriate design for the treatment offered. Additional limitations include the camp program itself. In the present format, weight-loss or fitness camps can be organized only during extended school vacation periods. They are limited in size, have a demanding staff/student ratio, and appear expensive. However, the cost should be contrasted with the cost of maintaining a child at home during the summer holidays and the costs of the short- and long-term consequences of obesity.
Finally, there is a question regarding generalizability. The benefits observed in this study may not be reproduced in other weight-loss camps. Differences in program structure and content, environment, participant backgrounds, and expectations may affect outcomes. Additional research is needed to address this and to investigate whether the intervention can be adapted to a nonresidential setting or delivered during the school term. Despite these cautions, these multiple short-term benefits suggest that camps such as this represent a valuable practical treatment option for overweight and obese children.
ACKNOWLEDGMENTS
This research was supported by a grant from the National Heart Research Fund (Leeds, United Kingdom).
FOOTNOTES
Accepted Oct 25, 2004.
No conflict of interest declared.
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