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Nutrition and Exercise Interventions to Improve Body Composition for Persons with Overweight or Obesity Near Retirement Age: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.
Eglseer, D, Traxler, M, Embacher, S, Reiter, L, Schoufour, JD, Weijs, PJM, Voortman, T, Boirie, Y, Cruz-Jentoft, A, Bauer, S
Advances in nutrition (Bethesda, Md.). 2023;14(3):516-538
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Obesity is characterised by excessive fat accumulation that often occurs during the process of aging. Aging is accompanied not only by a gradual increase in body fat stores but also a decrease in muscle mass, muscle function, and water retention. The aim of this study was to assess which nutrition and exercise interventions are most effective for improving the body composition (fat mass and muscle mass), body mass index, and waist circumference in persons with overweight or obesity near retirement age (55 to 70 years of age). This study was a systematic review and network meta-analysis (NMA) of randomised controlled trials of sixty-six studies. Results of the NMA showed that the most effective strategy to improve body composition, i.e., losing fat without increasing risk of sarcopenia in persons with obesity around retirement age, was combining energy restriction with resistance training or with mixed exercise (resistance combined with aerobic exercise) and/or high-protein intake. In fact, without training, an energy-restricted diet with or without added protein helped individuals lose fat mass but also tended to result in losses of muscle mass. Authors conclude that an energy-restricted diet alone probably contributes to the development of sarcopenic obesity in persons of retirement age. Thus, to simultaneously lose weight and maintain muscle mass, authors recommend a combination of energy restriction and resistance training.
Abstract
The retirement phase is an opportunity to integrate healthy (nutrition/exercise) habits into daily life. We conducted this systematic review to assess which nutrition and exercise interventions most effectively improve body composition (fat/muscle mass), body mass index (BMI), and waist circumference (WC) in persons with obesity/overweight near retirement age (ages 55-70 y). We conducted a systematic review and network meta-analysis (NMA) of randomized controlled trials, searching 4 databases from their inception up to July 12, 2022. The NMA was based on a random effects model, pooled mean differences, standardized mean differences, their 95% confidence intervals, and correlations with multi-arm studies. Subgroup and sensitivity analyses were also conducted. Ninety-two studies were included, 66 of which with 4957 participants could be used for the NMA. Identified interventions were clustered into 12 groups: no intervention, energy restriction (i.e., 500-1000 kcal), energy restriction plus high-protein intake (1.1-1.7 g/kg/body weight), intermittent fasting, mixed exercise (aerobic and resistance), resistance training, aerobic training, high protein plus resistance training, energy restriction plus high protein plus exercise, energy restriction plus resistance training, energy restriction plus aerobic training, and energy restriction plus mixed exercise. Intervention durations ranged from 8 wk to 6 mo. Body fat was reduced with energy restriction plus any exercise or plus high-protein intake. Energy restriction alone was less effective and tended to decrease muscle mass. Muscle mass was only significantly increased with mixed exercise. All other interventions including exercise effectively preserved muscle mass. A BMI and/or WC decrease was achieved with all interventions except aerobic training/resistance training alone or resistance training plus high protein. Overall, the most effective strategy for nearly all outcomes was combining energy restriction with resistance training or mixed exercise and high protein. Health care professionals involved in the management of persons with obesity need to be aware that an energy-restricted diet alone may contribute to sarcopenic obesity in persons near retirement age. This network meta-analysis is registered at https://www.crd.york.ac.uk/prospero/ as CRD42021276465.
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The Effect of Ketogenic Diet on Shared Risk Factors of Cardiovascular Disease and Cancer.
Mohammadifard, N, Haghighatdoost, F, Rahimlou, M, Rodrigues, APS, Gaskarei, MK, Okhovat, P, de Oliveira, C, Silveira, EA, Sarrafzadegan, N
Nutrients. 2022;14(17)
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Cardiovascular disease and cancer are major causes of mortality worldwide and share common pathophysiological mechanisms and risk factors. The ketogenic diet, a low-carbohydrate and high-fat diet, may alter metabolic pathways, potentially lowering the risk of developing these diseases. Specifically, the ketogenic diet improves energy metabolism by promoting the use of body ketones for energy production. This review examines the protective effects of the ketogenic diet in reducing cardiovascular disease and cancer risk and explores the underlying mechanisms. The ketogenic diet may suppress oxidative stress and inflammation while improving common risk factors such as obesity, hypertension, diabetes, and dyslipidaemia. It is important to conduct further rigorous studies to assess the long-term effects of the ketogenic diet. However, healthcare professionals can use these findings to understand the short-term benefits of the diet in managing metabolic abnormalities and reducing the risk of developing cardiovascular disease and cancer.
Abstract
Cardiovascular disease (CVD) and cancer are the first and second leading causes of death worldwide, respectively. Epidemiological evidence has demonstrated that the incidence of cancer is elevated in patients with CVD and vice versa. However, these conditions are usually regarded as separate events despite the presence of shared risk factors between both conditions, such as metabolic abnormalities and lifestyle. Cohort studies suggested that controlling for CVD risk factors may have an impact on cancer incidence. Therefore, it could be concluded that interventions that improve CVD and cancer shared risk factors may potentially be effective in preventing and treating both diseases. The ketogenic diet (KD), a low-carbohydrate and high-fat diet, has been widely prescribed in weight loss programs for metabolic abnormalities. Furthermore, recent research has investigated the effects of KD on the treatment of numerous diseases, including CVD and cancer, due to its role in promoting ketolysis, ketogenesis, and modifying many other metabolic pathways with potential favorable health effects. However, there is still great debate regarding prescribing KD in patients either with CVD or cancer. Considering the number of studies on this topic, there is a clear need to summarize potential mechanisms through which KD can improve cardiovascular health and control cell proliferation. In this review, we explained the history of KD, its types, and physiological effects and discussed how it could play a role in CVD and cancer treatment and prevention.
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Nutrition in Menopausal Women: A Narrative Review.
Silva, TR, Oppermann, K, Reis, FM, Spritzer, PM
Nutrients. 2021;13(7)
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Menopause is the permanent cessation of menstrual cycles following the loss of ovarian follicular activity. It is associated with increased prevalence of obesity, metabolic syndrome, cardiovascular disease, and osteoporosis. The aim of this narrative review was to discuss the current evidence on the association between dietary patterns and clinical endpoints in postmenopausal women (body composition, bone mass, and risk markers for cardiovascular disease), and thereby providing novel insight into the establishment of optimal dietary guidelines for healthy postmenopausal period. Research shows that: - the changes in weight and fat distribution in women are associated with aging and mainly with the decrease in oestradiol levels during peri- and post-menopause. - calcium, vitamin D, vitamin K, selenium, magnesium, and beta-carotene adequate intake could be linked with better BMD in postmenopausal women. - diet is a major modifiable risk factor for cardiovascular disease and could be a powerful intervention to reduce cardiovascular risks in postmenopausal women. - the Mediterranean diet is composed of healthy foods that have anti-inflammatory and antioxidant properties. Authors indicate that future studies evaluating the effects of low-fat, plant-based diets on fat mass in post-menopausal women are needed.
Abstract
Among the various aspects of health promotion and lifestyle adaptation to the postmenopausal period, nutritional habits are essential because they concern all women, can be modified, and impact both longevity and quality of life. In this narrative review, we discuss the current evidence on the association between dietary patterns and clinical endpoints in postmenopausal women, such as body composition, bone mass, and risk markers for cardiovascular disease. Current evidence suggests that low-fat, plant-based diets are associated with beneficial effects on body composition, but further studies are needed to confirm these results in postmenopausal women. The Mediterranean diet pattern along with other healthy habits may help the primary prevention of bone, metabolic, and cardiovascular diseases in the postmenopausal period. It consists on the use of healthy foods that have anti-inflammatory and antioxidant properties, and is associated with a small but significant decrease in blood pressure, reduction of fat mass, and improvement in cholesterol levels. These effects remain to be evaluated over a longer period of time, with the assessment of hard outcomes such as bone fractures, diabetes, and coronary ischemia.
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Vegetarian and Vegan Diet in Fibromyalgia: A Systematic Review.
Nadal-Nicolás, Y, Miralles-Amorós, L, Martínez-Olcina, M, Sánchez-Ortega, M, Mora, J, Martínez-Rodríguez, A
International journal of environmental research and public health. 2021;18(9)
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Fibromyalgia (FM) is a chronic non-degenerative disease of unknown etiology without effective medical treatment that mostly affects women. The aim of this study was to evaluate the efficacy of mainly plant-based diets in patients with FM compared to omnivorous diets. A secondary aim was to examine the main effects of these diets on patients’ symptoms and the improvement in their quality of life. This study is a systemic review of six studies (n = 4 clinical trials and n = 2 observational cohort studies). The selected studies included 157 FM patients in both the intervention and control groups, and more than 117 were women. Results indicate that a mainly plant-based diet improves biochemical parameters and body inflammation; body weight, sleep quality, quality of life, pain at rest as well as other symptoms of FM and their impact on health. Authors conclude that even though their findings are promising further well-designed clinical trials are needed to consolidate these dietary recommendations in FM patient.
Abstract
Fibromyalgia (FM) is a chronic non-degenerative disease characterized by the presence of multiple symptoms such as chronic pain, which negatively influence the quality of life of sufferers, most of whom are women. Currently, there is no effective treatment to limit the impact of these symptoms. The aim of this research is to review the scientific evidence on the effect of following a vegetarian or vegan diet on fibromyalgia patients. A systematic review included the original articles that answered the research question. These articles were in 2021 in the PubMed, Web of Science and Scopus databases. The research used the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. No time restriction was applied, and grey literature was not included. The evaluation of the methodological quality of the articles was carried out using the following different scales: STROBE (strengthening the reporting of observational studies in epidemiology), PEDro (Physiotherapy Evidence Database), and MMAT (Mixed Methods Appraisal Tool) scales. A total of 88 studies were analyzed, of which 6 investigations were included in this systematic review (n = 4 clinical trials and n = 2 cohort studies). These investigations show significant improvements in biochemical parameters, quality of life, quality of sleep, pain at rest and general health status when following mainly plant-based dietary patterns. In conclusion, these findings are promising but interpretation of the findings is limited due to the methodological quality of the studies. Well-designed clinical trials are needed to consolidate these dietary recommendations in FM patients.
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Sociodemographic and lifestyle-related risk factors for identifying vulnerable groups for type 2 diabetes: a narrative review with emphasis on data from Europe.
Kyrou, I, Tsigos, C, Mavrogianni, C, Cardon, G, Van Stappen, V, Latomme, J, Kivelä, J, Wikström, K, Tsochev, K, Nanasi, A, et al
BMC endocrine disorders. 2020;20(Suppl 1):134
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Type 2 diabetes mellitus (T2DM) results from progressive loss of insulin secretion, which is typically combined with various degrees of insulin resistance. The aim of this study is to provide a comprehensive overview of key sociodemographic and lifestyle-related risk factors for identifying vulnerable groups for T2DM with emphasis on data from Europe. This study is a narrative review which includes 101 publications. Literature shows that prevention of T2DM should be a collaborative effort which mobilizes multiple partners/ stakeholders at a national and international (e.g. European) level. In addition, a holistic approach is becoming increasingly essential in order to put into effect multidimensional public health programs and integrated interventions for effective T2DM prevention which will take into account both traditional and socioeconomic/socioecological factors. Authors conclude that a multidimensional approach for the prevention of T2DM may have a broader impact against the current diabesity epidemic within and across countries in Europe.
Abstract
BACKGROUND Type 2 diabetes mellitus (T2DM) comprises the vast majority of all diabetes cases in adults, with alarmingly increasing prevalence over the past few decades worldwide. A particularly heavy healthcare burden of diabetes is noted in Europe, where 8.8% of the population aged 20-79 years is estimated to have diabetes according to the International Diabetes Federation. Multiple risk factors are implicated in the pathogenesis of T2DM with complex underlying interplay and intricate gene-environment interactions. Thus, intense research has been focused on studying the role of T2DM risk factors and on identifying vulnerable groups for T2DM in the general population which can then be targeted for prevention interventions. METHODS For this narrative review, we conducted a comprehensive search of the existing literature on T2DM risk factors, focusing on studies in adult cohorts from European countries which were published in English after January 2000. RESULTS Multiple lifestyle-related and sociodemographic factors were identified as related to high T2DM risk, including age, ethnicity, family history, low socioeconomic status, obesity, metabolic syndrome and each of its components, as well as certain unhealthy lifestyle behaviors. As Europe has an increasingly aging population, multiple migrant and ethnic minority groups and significant socioeconomic diversity both within and across different countries, this review focuses not only on modifiable T2DM risk factors, but also on the impact of pertinent demographic and socioeconomic factors. CONCLUSION In addition to other T2DM risk factors, low socioeconomic status can significantly increase the risk for prediabetes and T2DM, but is often overlooked. In multinational and multicultural regions such as Europe, a holistic approach, which will take into account both traditional and socioeconomic/socioecological factors, is becoming increasingly crucial in order to implement multidimensional public health programs and integrated community-based interventions for effective T2DM prevention.
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Resistance Training Prevents Muscle Loss Induced by Caloric Restriction in Obese Elderly Individuals: A Systematic Review and Meta-Analysis.
Sardeli, AV, Komatsu, TR, Mori, MA, Gáspari, AF, Chacon-Mikahil, MPT
Nutrients. 2018;10(4)
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Caloric restriction (55% carbohydrate, 15% protein, 30% fat) is associated with increased lifespans and the attenuation of the harmful effects of aging. Furthermore, it has been shown that resistance training increases lean body mass, promotes strength, and attenuates muscle loss and function in elderly people. The aim of the study is to determine the level of lean body mass that can be preserved when resistance training is associated with caloric restriction interventions in elderly obese humans. The study is a meta-analysis, based on data from randomised-controlled trials. The participants were older adults or elderly people with a mean age > 57 year. Results indicate that caloric restriction associated with resistance training prevents 93% lean body mass loss induced by caloric restriction. Authors conclude that caloric restriction with resistance training almost stopped caloric restriction induced lean body mass loss completely.
Abstract
It remains unclear as to what extent resistance training (RT) can attenuate muscle loss during caloric restriction (CR) interventions in humans. The objective here is to address if RT could attenuate muscle loss induced by CR in obese elderly individuals, through summarized effects of previous studies. Databases MEDLINE, Embase and Web of Science were used to perform a systematic search between July and August 2017. Were included in the review randomized clinical trials (RCT) comparing the effects of CR with (CRRT) or without RT on lean body mass (LBM), fat body mass (FBM), and total body mass (BM), measured by dual-energy X-ray absorptiometry, on obese elderly individuals. The six RCTs included in the review applied RT three times per week, for 12 to 24 weeks, and most CR interventions followed diets of 55% carbohydrate, 15% protein, and 30% fat. RT reduced 93.5% of CR-induced LBM loss (0.819 kg [0.364 to 1.273]), with similar reduction in FBM and BM, compared with CR. Furthermore, to address muscle quality, the change in strength/LBM ratio tended to be different (p = 0.07) following CRRT (20.9 ± 23.1%) and CR interventions (−7.5 ± 9.9%). Our conclusion is that CRRT is able to prevent almost 100% of CR-induced muscle loss, while resulting in FBM and BM reductions that do not significantly differ from CR.
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Consumption of ultra-processed foods and body fat during childhood and adolescence: a systematic review.
Costa, CS, Del-Ponte, B, Assunção, MCF, Santos, IS
Public health nutrition. 2018;21(1):148-159
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Childhood and adolescent obesity has presented a growing prevalence over the last three decades. Consumption of ultra-processed foods has been pointed out as a risk factor for increasing obesity, as measured by body mass index, among both adolescents and adults. The aim of this study was to identify papers on the association between consumption of ultra-processed food and body fat during childhood and adolescence. This study is a systemic review of 26 articles that evaluated groups of ultra-processed foods or specific ultra-processed foods. Results showed positive associations between consumption of ultra-processed foods and body fat levels. Authors conclude that the use of a standardized food classification, which makes it possible to consider the level of food processing, is much needed in future studies in order to uncover the role of such foods in obesity epidemics.
Abstract
OBJECTIVE To review the available literature on the association between consumption of ultra-processed foods and body fat during childhood and adolescence. DESIGN A systematic review was conducted in the PubMed, Web of Science and LILACS databases. Studies that evaluated the association between consumption of ultra-processed food (exposure) and body fat (outcome) during childhood and adolescence were eligible. SUBJECTS Healthy children and adolescents. RESULTS Twenty-six studies that evaluated groups of ultra-processed foods (such as snacks, fast foods, junk foods and convenience foods) or specific ultra-processed foods (soft drinks/sweetened beverages, sweets, chocolate and ready-to-eat cereals) were selected. Most of the studies (n 15) had a cohort design. Consumption was generally evaluated by means of FFQ or food records; and body composition, by means of double indirect methods (bioelectrical impedance analysis and skinfolds). Most of the studies that evaluated consumption of groups of ultra-processed foods and soft drinks/sweetened beverages found positive associations with body fat. CONCLUSIONS Our review showed that most studies have found positive associations between consumption of ultra-processed food and body fat during childhood and adolescence. There is a need to use a standardized classification that considers the level of food processing to promote comparability between studies.
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Lifestyle Risk Factors for Serrated Colorectal Polyps: A Systematic Review and Meta-analysis.
Bailie, L, Loughrey, MB, Coleman, HG
Gastroenterology. 2017;152(1):92-104
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Colorectal cancer (CRC) is a heterogeneous disease thought to result from the accumulation of various aberrant mutations in the cells lining the colorectal mucosa. The aim of this systematic review and meta-analysis was to evaluate modifiable and lifestyle factors and the risk of serrated polyps (a type of growth that stick out from the surface of the colon or rectum) of the colorectum. A search of 3 databases yielded a potential 2446 studies for inclusion, from which 43 remained for systematic review. Results indicate that smoking, alcohol consumption, body fatness, dietary fat and meat consumption increased the risk of developing serrated polyps. Whereas, nonsteroidal anti-inflammatory drugs, aspirin and dietary folate decreased this risk. Authors conclude that their findings strengthen public health messages promoting awareness and change in order to reduce the risk of these precancerous lesions and consequently CRC.
Abstract
BACKGROUND & AIMS Certain subsets of colorectal serrated polyps (SP) have malignant potential. We performed a systematic review and meta-analysis to investigate the association between modifiable lifestyle factors and risk for SPs. METHODS We conducted a systematic search of Medline, Embase, and Web of Science for observational or interventional studies that contained the terms risk or risk factor, and serrated or hyperplastic, and polyps or adenomas, and colorectal (or synonymous terms), published by March 2016. Titles and abstracts of identified articles were independently reviewed by at least 2 reviewers. Adjusted relative risk (RR) and 95% confidence interval (CI) were combined using random effects meta-analyses to assess the risk of SP, when possible. RESULTS We identified 43 studies of SP risk associated with 7 different lifestyle factors: smoking, alcohol, body fatness, diet, physical activity, medication, and hormone-replacement therapy. When we compared the highest and lowest categories of exposure, factors we found to significantly increase risk for SP included tobacco smoking (RR, 2.47; 95% CI, 2.12-2.87), alcohol intake (RR, 1.33; 95% CI, 1.17-1.52), body mass index (RR, 1.40; 95% CI, 1.22-1.61), and high intake of fat or meat. Direct associations for smoking and alcohol, but not body fat, tended to be stronger for sessile serrated adenomas/polyps than hyperplastic polyps. In contrast, factors we found to significantly decrease risks for SP included use of nonsteroidal anti-inflammatory drugs (RR, 0.77; 95% CI, 0.65-0.92) or aspirin (RR, 0.81; 95% CI, 0.67-0.99), as well as high intake of folate, calcium, or fiber. No significant associations were detected between SP risk and physical activity or hormone replacement therapy. CONCLUSIONS Several lifestyle factors, most notably smoking and alcohol, are associated with SP risk. These findings enhance our understanding of mechanisms of SP development and indicate that risk of serrated pathway colorectal neoplasms could be reduced with lifestyle changes.
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Diet Behavior Change Techniques in Type 2 Diabetes: A Systematic Review and Meta-analysis.
Cradock, KA, ÓLaighin, G, Finucane, FM, McKay, R, Quinlan, LR, Martin Ginis, KA, Gainforth, HL
Diabetes care. 2017;40(12):1800-1810
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Dietary behaviour is intrinsically linked to type 2 diabetes. Dietary factors have been linked to the highest proportion of deaths in type 2 diabetes, stroke, and heart disease. Identifying effective ways to help suffers successfully change to more effective dietary behaviours may help condition management and reduce disease progression. The objective of the systemic review and meta-analysis was to identify dietary behaviour change techniques, intervention features, and specific diets associated with changes in blood glucose levels (HbA1c) and body weight in type 2 diabetes. It included 54 studies, all of whose participants have type 2 diabetes. High-protein diets and meal replacement programs produced the greatest reductions in blood glucose (measured by HbA1c). Behavioural change techniques including 'problem solving,' 'feedback on behaviour,' 'adding objects to the environment' and 'social comparison' as well as interventions that were build on behavioural change theory were associated with clinically significant reductions in blood glucose as measured by HbA1c (a reduction of ≥0.3% (3.3 mmol/mol). However, the findings show that changing or controlling (e.g. providing all food) dietary environmental factors may be more effective than strategies to change dietary behaviour to reduce blood glucose levels in adults with type 2 diabetes. The authors conclude that changing the dietary environment may be more important than focusing on dietary behaviour in type 2 diabetes treatment.
Abstract
OBJECTIVE Dietary behavior is closely connected to type 2 diabetes. The purpose of this meta-analysis was to identify behavior change techniques (BCTs) and specific components of dietary interventions for patients with type 2 diabetes associated with changes in HbA1c and body weight. RESEARCH DESIGN AND METHODS The Cochrane Library, CINAHL, Embase, PubMed, PsycINFO, and Scopus databases were searched. Reports of randomized controlled trials published during 1975-2017 that focused on changing dietary behavior were selected, and methodological rigor, use of BCTs, and fidelity and intervention features were evaluated. RESULTS In total, 54 studies were included, with 42 different BCTs applied and an average of 7 BCTs used per study. Four BCTs-"problem solving," "feedback on behavior," "adding objects to the environment," and "social comparison"-and the intervention feature "use of theory" were associated with >0.3% (3.3 mmol/mol) reduction in HbA1c. Meta-analysis revealed that studies that aimed to control or change the environment showed a greater reduction in HbA1c of 0.5% (5.5 mmol/mol) (95% CI -0.65, -0.34), compared with 0.32% (3.5 mmol/mol) (95% CI -0.40, -0.23) for studies that aimed to change behavior. Limitations of our study were the heterogeneity of dietary interventions and poor quality of reporting of BCTs. CONCLUSIONS This study provides evidence that changing the dietary environment may have more of an effect on HbA1c in adults with type 2 diabetes than changing dietary behavior. Diet interventions achieved clinically significant reductions in HbA1c, although initial reductions in body weight diminished over time. If appropriate BCTs and theory are applied, dietary interventions may result in better glucose control.
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Efficacy of exercise for treating overweight in children and adolescents: a systematic review.
Atlantis, E, Barnes, EH, Singh, MA
International journal of obesity (2005). 2006;30(7):1027-40
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The global number of overweight and obese children/adolescents is increasing at an alarming rate. This systematic review and meta-analysis aimed to assess the impact of exercise for overweight children/adolescents. Fourteen randomised controlled trials (RCTs) were included in the analysis. Overall the reduction in average body weight and central obesity was not significant. However, it was found that exercise did significantly reduce body fat percentage by 0.6% in studies that involved more exercise (more than 3 days a week) for children with an average age of 12. When results were grouped by exercise amount, it was found that higher amounts had greater effect. Additionally, trials with longer intervention length saw greater effects. None of the trials reached the level of exercise recommended for children by UK/US guidelines (at least 60 minutes a day). The author suggested further studies of longer duration in this area are required to clarify exercise amount response.
Abstract
BACKGROUND Overweight prevalence among children/adolescents is increasing, while adult obesity may potentially cause a decline in life expectancy. More exercise is uniformly recommended, although treatment efficacy remains unclear. OBJECTIVE To determine the efficacy of exercise alone for treating overweight in children/adolescents. DESIGN A systematic review and meta-analysis of randomized trials published in English were completed following multiple database searches performed on December 10, 2004. Studies of isolated or adjunctive exercise/physical activity treatment in overweight/obese children or adolescents which reported any overweight outcome were included. Literature searches identified 645 papers which were manually searched, of which 45 were considered for inclusion, of which 13 papers which reported 14 studies were included (N=481 overweight boys and girls, aged approximately 12 years). Two reviewers independently identified relevant papers for potential inclusion and assessed methodological quality. Principal measures of effects included the mean difference (MD) (between treatment and control groups), the weighted MD (WMD), and the standardized MD (SMD). RESULTS Few studies were of robust design. The pooled SMD was -0.4 (-0.7, -0.1, P=0.006) for percent body fat, and -0.2 (-0.6, 0.1, P=0.07) for central obesity outcomes, whereas the pooled WMD was -2.7 kg (-6.1 kg, 0.8 kg, P=0.07) for body weight, all of which favored exercise. Pooled effects on body weight were significant and larger for studies of higher doses, whereas nonsignificant and smaller effects were seen for studies of lower doses of exercise (155-180 min/weeks vs 120-150 min/weeks). CONCLUSIONS Based on the small number of short-term randomized trials currently available, an aerobic exercise prescription of 155-180 min/weeks at moderate-to-high intensity is effective for reducing body fat in overweight children/adolescents, but effects on body weight and central obesity are inconclusive. Recommendations for future study designs are discussed.