The Effects of Exercise on Bone Mineral Density in Men: A Systematic Review and Meta-Analysis of Randomised Controlled Trials.

The aim of this systematic review and meta-analysis was to provide an updated analysis, including the use of more robust methods, on the effects of exercise on bone mineral density in men. Randomised Control Trials of > 24 weeks and published in English up to 01/05/20 were retrieved from 3 electronic databases, cross-referencing, and expert review. The primary outcome measures were changes in FN, LS, and lower limb BMD Standardised effect sizes were calculated from each study and pooled using the inverse heterogeneity model. A statistically significant benefit of exercise was observed on FN BMD [g = 0.21 (0.03, 0.40), Z = 2.23 p = 0.03], with no observed statistically significant benefit of exercise on LS BMD [g = 0.10 (- 0.07, 0.26), Z = 1.15 p = 0.25]. This analysis provided additional evidence to recommend ground- and/or joint-reaction force exercises for improving or maintaining FN, but not LS BMD. Additional well-designed RCTs are unlikely to alter this evidence, although interventions that include activities that directly load the lumbar spine are needed to ensure this is not a potential method of improving LS BMD.

Are There Interindividual Differences in Anxiety as a Result of Aerobic Exercise Training in Adults With Fibromyalgia? An Ancillary Meta-analysis of Randomized Controlled Trials.

OBJECTIVE: To determine whether true interindividual response differences (IIRD) exist with respect to changes in anxiety because of aerobic exercise training in adults with fibromyalgia (FM). DATA SOURCES: Data from a previous meta-analytical database of randomized controlled trials of exercise in adults with arthritis and other rheumatic diseases. STUDY SELECTION: Randomized controlled trials limited to aerobic exercise training on anxiety in adults 18 years or older with FM were included. DATA EXTRACTION: Change outcome SDs treated as point estimates for anxiety were used to calculate true IIRD from each study. In addition, treatment effect data were extracted. DATA SYNTHESIS: The inverse variance heterogeneity model was used to pool all results. For the 5 studies and 321 participants in which results were pooled, statistically significant treatment effect reductions in anxiety were observed (mean, -0.77 points, 95% CI, -1.25 to -0.77). However, no significant IIRD were found (mean, 0.6 points, 95% CI, -1.2 to 1.5). The 95% prediction interval for true IIRD in a future study was -1.7 to 0.8. The percent chance, ie, probability, of a clinically meaningful difference in variability, was 61.5% (only possibly clinically important). CONCLUSIONS: The results of the current study suggest that aerobic exercise is associated with reductions in anxiety among adults with fibromyalgia. However, there is currently a lack of convincing evidence to support the notion that true IIRD exist. Therefore, a search for potential mediators and moderators associated with aerobic exercise and changes in anxiety among adults with FM may not be warranted. However, additional research is needed before any true level of certainty can be established. This includes (1) the assessment of IIRD in future randomized controlled trials, (2) randomized controlled trials of longer duration, and (3) an increase in the proportion of men included in randomized controlled trials.

Isometric exercise and inter-individual response differences on resting systolic and diastolic blood pressure in adults: a meta-analysis of randomized controlled trials.

PURPOSE: Isometric exercise (IE) has been shown to reduce resting systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults. However, no one to date has determined whether true inter-individual response differences (IIRD) versus random variability exist with respect to IE and resting SBP and DBP in adults ≥18 years of age. The purpose of the current study was to address this gap. METHODS AND MATERIALS: Using the meta-analytic approach, randomised controlled trials from a recent meta-analysis that examined the effects of IE on resting SBP and DBP were included. Change outcome standard deviations for SBP and DBP from IE and control groups were used to calculate true IIRD from each study. The inverse variance heterogeneity (IVhet) model was used to pool results. RESULTS: Pooled changes for true IIRD in SBP (16 studies, 411 participants) were 3.3 mmHg (95% confidence interval, -3.1 to 5.6 mmHg) while tau (τ) was 4.2. For DBP, true IIRD (16 studies, 411 participants) were 2.3 mmHg (95% confidence interval, -0.7 to 3.3 mmHg) while tau (τ) was 2.2. The 95% prediction interval for true IIRD in a future study was -5.8 to 7.4 mmHg for SBP and -2.7 to 4.2 mmHg for DBP. The percent chance, i.e. probability, of a clinically meaningful difference of 2 mmHg was 68% for SBP and 75% for DBP, both of which were only considered as 'possibly clinically important'. CONCLUSION: While IE reduces resting SBP and DBP in adults, the results of the current study suggest that random variability versus true IIRD account for any potential differences as a result of IE on changes in resting SBP and DBP in adults. Thus, a search for potential moderators and mediators, including potential genetic interactions associated with IE, may not be warranted.

Number of Physically Inactive Adults With Arthritis in the United States Who Could Improve Physical Function and Pain Control by Exercising.

We estimated the number of physically inactive US adults with arthritis by state and nationally who could improve their physical function and pain control by participating in an exercise program. Our calculations were based on number-needed-to-treat, arthritis prevalence, physical inactivity, and 2010 US Census data. Estimates were lowest in the District of Columbia (physical function, n = 4,412; pain, n = 2,451) and highest in Texas (physical function, n = 325,504; pain, n = 180,835). Overall estimates were 4,119,792 for physical function and 2,288,771 for pain control. State-level estimates are important for allocating resources, public health program planning, and future research.

Systematic reviews and meta-analysis in nutrition research.

There exists an ever-increasing number of systematic reviews, with or without meta-analysis, in the field of nutrition. Concomitant with this increase is the increased use of such to guide future research as well as both practice and policy-based decisions. Given this increased production and consumption, a need exists to educate both producers and consumers of systematic reviews, with or without meta-analysis, on how to conduct and evaluate high-quality reviews of this nature in nutrition. The purpose of this paper is to try and address this gap. In the present manuscript, the different types of systematic reviews, with or without meta-analyses, are described as well as the description of the major elements, including methodology and interpretation, with a focus on nutrition. It is hoped that this non-technical information will be helpful to producers, reviewers and consumers of systematic reviews, with or without meta-analysis, in the field of nutrition.

Systematic reviews and cancer research: a suggested stepwise approach.

Systematic reviews, with or without meta-analysis, play an important role today in synthesizing cancer research and are frequently used to guide decision-making. However, there is now an increase in the number of systematic reviews on the same topic, thereby necessitating a systematic review of previous systematic reviews. With a focus on cancer, the purpose of this article is to provide a practical, stepwise approach for systematically reviewing the literature and publishing the results. This starts with the registration of a protocol for a systematic review of previous systematic reviews and ends with the publication of an original or updated systematic review, with or without meta-analysis, in a peer-reviewed journal. Future directions as well as potential limitations of the approach are also discussed. It is hoped that the stepwise approach presented in this article will be helpful to both producers and consumers of cancer-related systematic reviews and will contribute to the ultimate goal of preventing and treating cancer.

Exercise and cancer-related fatigue in adults: a systematic review of previous systematic reviews with meta-analyses.

BACKGROUND: Conduct a systematic review of previous systematic reviews with meta-analysis to determine the effects of exercise (aerobic, strength or both) on cancer-related-fatigue (CRF) in adults with any type of cancer. METHODS: Systematic reviews with meta-analyses of previous randomized controlled trials published through July of 2016 were included by searching six electronic databases and cross-referencing. Dual-selection and data abstraction were conducted. Methodological quality was assessed using the Assessment of Multiple Systematic Reviews (AMSTAR) instrument. Standardized mean differences (SMD) that were pooled using random-effects models were included as the effect size. In addition, 95% prediction intervals (PI), number needed-to-treat (NNT) and percentile improvements were calculated. RESULTS: Sixteen studies representing 2 to 48 SMD effect sizes per analysis (mean ± SD, 7 ± 8, median = 5) and 37 to 3254 participants (mean ± SD, 633 ± 690, median = 400) were included. Length of training lasted from 3 to 52 weeks (mean ± SD, 14.6 ± 3.1, median = 14), frequency from 1 to 10 times per week (mean ± SD, 3.4 ± 0.8, median = 3), and duration from 10 to 120 min per session (mean ± SD, 44.3 ± 5.5, median = 45). Adjusted AMSTAR scores ranged from 44.4% to 80.0% (mean ± SD, 68.8% ± 12.0%, median = 72.5%). Overall, mean SMD improvements in CRF ranged from -1.05 to -0.01, with 22 of 55 meta-analytic results (52.7%) statistically significant (non-overlapping 95% CI). When PI were calculated for results with non-overlapping 95% CI, only 3 of 25 (12%) yielded non-overlapping 95% PI favoring reductions in CRF. Number needed-to-treat and percentile improvements ranged from 3 to 16 and 4.4 to 26.4, respectively. CONCLUSIONS: A lack of certainty exists regarding the benefits of exercise on CRF in adults. However, exercise does not appear to increase CRF in adults. TRIAL REGISTRATION: PROSPERO Registration # CRD42016045405 .

Effects of exercise on BMI z-score in overweight and obese children and adolescents: a systematic review with meta-analysis.

BACKGROUND: Overweight and obesity are major public health problems in children and adolescents. The purpose of this study was to conduct a systematic review with meta-analysis to determine the effects of exercise (aerobic, strength or both) on body mass index (BMI) z-score in overweight and obese children and adolescents. METHODS: Studies were included if they were randomized controlled exercise intervention trials ≥ 4 weeks in overweight and obese children and adolescents 2 to 18 years of age, published in any language between 1990-2012 and in which data were available for BMI z-score. Studies were retrieved by searching eleven electronic databases, cross-referencing and expert review. Two authors (GAK, KSK) selected and abstracted data. Bias was assessed using the Cochrane Risk of Bias Assessment Instrument. Exercise minus control group changes were calculated from each study and weighted by the inverse of the variance. All results were pooled using a random-effects model with non-overlapping 95% confidence intervals (CI) considered statistically significant. Heterogeneity was assessed using Q and I2 while funnel plots and Egger's regression test were used to assess for small-study effects. Influence and cumulative meta-analysis were performed as well as moderator and meta-regression analyses. RESULTS: Of the 4,999 citations reviewed, 835 children and adolescents (456 exercise, 379 control) from 10 studies representing 21 groups (11 exercise, 10 control) were included. On average, exercise took place 4 x week for 43 minutes per session over 16 weeks. Overall, a statistically significant reduction equivalent to 3% was found for BMI z-score (Χ¯, -0.06, 95% CI, -0.09 to -0.03; Q = 24.9, p = 0.01; I(2)=59.8%). No small-study effects were observed and results remained statistically significant when each study was deleted from the model once. Based on cumulative meta-analysis, results have been statistically significant since 2009. None of the moderator or meta-regression analyses were statistically significant. The number-needed-to treat was 107 with an estimated 116,822 million obese US children and adolescents and approximately 1 million overweight and obese children and adolescents worldwide potentially improving their BMI z-score by participating in exercise. CONCLUSIONS: Exercise improves BMI z-score in overweight and obese children and adolescents and should be recommended in this population group. However, a need exists for additional studies on this topic.

Effects of exercise on depressive symptoms in adults with arthritis and other rheumatic disease: a systematic review of meta-analyses.

BACKGROUND: Depression is a major public health problem among adults with arthritis and other rheumatic disease. The purpose of this study was to conduct a systematic review of previous meta-analyses addressing the effects of exercise (aerobic, strength or both) on depressive symptoms in adults with osteoarthritis, rheumatoid arthritis, fibromyalgia and systemic lupus erythematous. METHODS: Previous meta-analyses of randomized controlled trials were included by searching nine electronic databases and cross-referencing. Methodological quality was assessed using the Assessment of Multiple Systematic Reviews (AMSTAR) Instrument. Random-effects models that included the standardized mean difference (SMD) and 95% confidence intervals (CIs) were reported. The alpha value for statistical significance was set at p ≤ 0.05. The U3 index, number needed to treat (NNT) and number of US people who could benefit were also calculated. RESULTS: Of the 95 citations initially identified, two aggregate data meta-analyses representing 6 and 19 effect sizes in as many as 870 fibromyalgia participants were included. Methodological quality was 91% and 82%, respectively. Exercise minus control group reductions in depressive symptoms were found for both meta-analyses (SMD, -0.61, 95% CI, -0.99 to -0.23, p = 0.002; SMD, -0.32, 95% CI, -0.53 to -0.12, p = 0.002). Percentile improvements (U3) were equivalent to 22.9 and 12.6. The number needed to treat was 6 and 9 with an estimated 0.83 and 0.56 million US people with fibromyalgia potentially benefitting. CONCLUSIONS: Exercise improves depressive symptoms in adults with fibromyalgia. However, a need exists for additional meta-analytic work on this topic.

Resistance training and inter-interindividual response differences on cardiorespiratory fitness in older adults: An ancillary meta-analysis of randomized controlled trials.

Examine true inter-individual response differences (IIRD) as a result of resistance training on cardiorespiratory fitness in older adults. Data from a recent meta-analysis of 22 randomized controlled trials representing 552 men and women (292 resistance training, 260 control) ≥ 60 years of age were included. The primary outcome was cardiorespiratory fitness (VO2max) in ml.kg-1.min-1. Using the inverse variance heterogeneity (IVhet) model, statistically significant treatment effect (resistance training minus control) increases in VO2max in ml.kg-1.min-1 were found (mean, 1.8, 95% CI, 0.4 to 3.3 ml.kg-1.min-1, p = 0.01; Q = 82.8, p < 0.001; I2 = 74.6%, 95% CI, 61.6 to 83.3%; τ2 =1.1). The 95% prediction interval (PI) was -0.8 to 4.5 ml.kg-1.min-1. However, no statistically significant IIRD was observed (mean, 0.6, 95% CI, -1.1 to 1.4 ml.kg-1.min-1; τ2 =1.5). The 95% PI was -1.8 to 2.0 ml.kg-1.min-1. In conclusion, while progressive resistance training may increase VO2max in ml.kg-1.min-1, a lack of true resistance-training-associated IIRD exist.

Representation of adults with rheumatoid arthritis in US-based randomized controlled exercise trials: a systematic review with meta-analysis.

The purpose of this study was to conduct a systematic review with meta-analysis to determine the representation of adults with rheumatoid arthritis (RA) according to sex, race, and ethnicity in exercise randomized controlled trials (RCTs) conducted in the USA. Exercise RCTs ≥ 4 weeks conducted in the USA in adults ≥ 18 years with RA were eligible. Studies were retrieved by searching six electronic databases, cross-referencing and searching a clinical trials registry. Dual, independent, study selection and data abstraction were conducted. The primary outcomes were the proportion of participants in each study according to sex as well as race/ethnicity. Results were pooled meta-analytically using the inverse-variance heterogeneity (IVhet) model after applying the double-arcsine transformation. Of the 1030 unique articles screened, five RCTs representing 353 participants with RA were included. The pooled participant prevalence was 83% (95% CI = 73 to 92%) for women and 17% (95% CI = 8 to 27%) for men, suggesting an over-representation of women and an under-representation of men by approximately 7.4% based on current prevalence US estimates for each. Qualitative examination for race and ethnicity demonstrated an under-representation of racial/ethnic minority groups. There is a lack of representation of men with RA in US-based randomized controlled exercise intervention studies. Additional US-based randomized controlled exercise trials, including greater inclusion and reporting of the racial/ethnic composition of participants, are also needed. Key Points • This systematic review with meta-analysis of US studies found an under-representation of men in randomized controlled trials examining the effects of exercise in those with rheumatoid arthritis (RA). • Qualitative examination according to race/ethnicity found both a lack of reporting as well as under-representation of selected racial/ethnic minorities in US-based randomized controlled exercise studies among adults with RA. • This study highlights the need for additional US-based randomized controlled trials of exercise in adults with RA that better represent the RA population in the USA.

Effects of resistance training on body weight and body composition in older adults: An inter-individual response difference meta-analysis of randomized controlled trials.

Whether true inter-individual response differences (IIRD) occur as a result of resistance training on body weight and body composition in older adults with overweight and obesity is not known. To address this gap, data from a previous meta-analysis representing 587 men and women (333 resistance training, 254 control) ≥ 60 years of age nested in 15 randomized controlled trials of resistance training ≥ 8 weeks were included. Resistance training and control group change outcome standard deviations treated as point estimates for body weight and body composition (percent body fat, fat mass, body mass index in kg.m2, and lean body mass) were used to calculate true IIRD from each study. True IIRD as well as traditional pairwise comparisons were pooled using the inverse-variance (IVhet) model. Both 95% confidence intervals (CI) and prediction intervals (PI) were calculated. While statistically significant improvements were found for body weight and all body composition outcomes (p < 0.05 for all), no statistically significant IIRD was observed for any of the outcomes (p > 0.05 for all) and all 95% PIs overlapped. Conclusions: While resistance training is associated with improvements in body weight and body composition in older adults, the lack of true IIRD suggests that factors other than training response variation (random variation, physiological responses associated with behavioral changes that are not the result of resistance training) are responsible for the observed variation in body weight and body composition.

Effects of ground and joint reaction force exercise on lumbar spine and femoral neck bone mineral density in postmenopausal women: a meta-analysis of randomized controlled trials.

BACKGROUND: Low bone mineral density (BMD) and subsequent fractures are a major public health problem in postmenopausal women. The purpose of this study was to use the aggregate data meta-analytic approach to examine the effects of ground (for example, walking) and/or joint reaction (for example, strength training) exercise on femoral neck (FN) and lumbar spine (LS) BMD in postmenopausal women. METHODS: The a priori inclusion criteria were: (1) randomized controlled trials, (2) exercise intervention ≥ 24 weeks, (3) comparative control group, (4) postmenopausal women, (5) participants not regularly active, i.e., less than 150 minutes of moderate intensity (3.0 to 5.9 metabolic equivalents) weight bearing endurance activity per week, less than 75 minutes of vigorous intensity (> 6.0 metabolic equivalents) weight bearing endurance activity per week, resistance training < 2 times per week, (6) published and unpublished studies in any language since January 1, 1989, (7) BMD data available at the FN and/or LS. Studies were located by searching six electronic databases, cross-referencing, hand searching and expert review. Dual selection of studies and data abstraction were performed. Hedge's standardized effect size (g) was calculated for each FN and LS BMD result and pooled using random-effects models. Z-score alpha values, 95%confidence intervals (CI) and number-needed-to-treat (NNT) were calculated for pooled results. Heterogeneity was examined using Q and I2. Mixed-effects ANOVA and simple meta-regression were used to examine changes in FN and LS BMD according to selected categorical and continuous variables. Statistical significance was set at an alpha value ≤0.05 and a trend at >0.05 to ≤ 0.10. RESULTS: Small, statistically significant exercise minus control group improvements were found for both FN (28 g's, 1632 participants, g = 0.288, 95% CI = 0.102, 0.474, p = 0.002, Q = 90.5, p < 0.0001, I2 = 70.1%, NNT = 6) and LS (28 g's, 1504 participants, g = 0.179, 95% CI = -0.003, 0.361, p = 0.05, Q = 77.7, p < 0.0001, I2 = 65.3%, NNT = 6) BMD. Clinically, it was estimated that the overall changes in FN and LS would reduce the 20-year relative risk of osteoporotic fracture at any site by approximately 11% and 10%, respectively. None of the mixed-effects ANOVA analyses were statistically significant. Statistically significant, or a trend for statistically significant, associations were observed for changes in FN and LS BMD and 20 different predictors. CONCLUSIONS: The overall findings suggest that exercise may result in clinically relevant benefits to FN and LS BMD in postmenopausal women. Several of the observed associations appear worthy of further investigation in well-designed randomized controlled trials.

Walking and resting blood pressure: An inter-individual response difference meta-analysis of randomized controlled trials.

CONCLUSIONS: While walking is associated with reductions in resting SBP and DBP, a lack of true IIRD exists, suggesting that factors other than training response variation (random variation, physiological responses associated with behavioral changes that are not the result of walking) are responsible for the observed variation in resting SBP and DBP.

Clinical relevance of Tai Chi on pain and physical function in adults with knee osteoarthritis: An ancillary meta-analysis of randomized controlled trials.

The clinical relevance of Tai Chi on pain, stiffness, and physical function in adults with knee osteoarthritis (KOA) has not been established. Therefore, the purpose of the current study was to address this gap. Eight randomized controlled trials from a recent meta-analysis representing 407 participants (216 Tai Chi, 191 control) in adults ≥18 years of age with KOA and included the assessment of pain, stiffness, and physical function using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) were assessed. The inverse variance heterogeneity model (IVhet) was first used to pool standardized mean difference effect sizes (ES) for each outcome. Clinical relevance, i.e., number-needed-to treat (NNT) ≤10 and relative risk reduction (RRR) ≥25% was calculated across assumed controlled risks (ACR) ranging from 0.01 to 0.99. Statistically significant improvements were found for pain (ES, -0.75, 95% CI, -0.99, -0.51; Q = 8.9, p = 0.26; I2 = 21%), stiffness (ES, -0.70, 95% CI, -0.95, -0.46; Q = 9.6, p = 0.21; I2 = 27%), and physical function (ES, -0.91, 95% CI, -1.12, -0.70; Q = 7.2, p = 0.40; I2 = 3%). The intersection of results for a NNT ≤10 and RRR ≥25% yielded high evidence and clinically relevant improvements across a wide range of ACR for pain (0.15 to 0.88), stiffness (0.15 to 0.87), and physical function (0.13 to 0.97). These findings suggest that Tai Chi results in statistically significant as well as clinically important improvements in pain, stiffness, and physical function across a wide range of ACR in adults with KOA.

Exercise and Cardiovascular Disease Risk Factors in Children and Adolescents With Obesity: A Systematic Review With Meta-Analysis of Randomized Controlled Trials.

The purpose of this study was to examine the effects of exercise on cardiovascular disease (CVD) risk factors in children and adolescents with obesity. Randomized controlled trials (RCTs) of exercise ≥4 weeks in children and adolescents with obesity were included if one or more CVD risk factors were included as an outcome. Studies were retrieved by searching 7 electronic databases, cross-referencing, and expert review. Data were pooled using the inverse-variance heterogeneity (IVhet) model and strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) instrument. Thirty-nine studies representing 1548 participants (847 exercise, 701 control) met the inclusion criteria. Aerobic exercise improved 10 of 12 (83.3%) outcomes (P < .05 for all) while combined aerobic and strength training improved 5 of 8 (62.5%) outcomes (P < .05 for all). The strength of evidence ranged from "very low" to "moderate." It was concluded that aerobic exercise, as well as combined aerobic and strength training, is associated with improvements in multiple CVD risk factors among children and adolescents with obesity. However, the generally low strength of evidence suggests a need for future well-designed and conducted RCTs on the effects of exercise, especially strength training, in children and adolescents with obesity.

Inter-individual response differences on resting blood pressure as a result of qigong in adults: An ancillary meta-analysis of randomized trials.

OBJECTIVE: Conduct an ancillary meta-analysis to determine whether true inter-individual response differences (IIRD) exist with respect to the effects of qigong on resting systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults. METHODS: Data from a meta-analysis representing 370 participants (181 qigong, 189 control) from 7 randomized trials on qigong and resting SBP and DBP in men and women were included. Qigong and control group change outcome standard deviations treated as point estimates for both resting SBP and DBP were used to calculate true IIRD from each study. The inverse variance heterogeneity (IVhet) model was used to pool results. RESULTS: For participants with essential hypertension, statistically significant and clinically important reductions in resting SBP (X̅, -18.2 mmHg, 95% CI, -21.3 to -15.2 mmHg) and DBP (X̅, -11.7 mmHg, 95% CI, -17.0 to -6.3 mmHg) were found. However, true IIRD were neither significant nor clinically important for either SBP (X̅, -6.0 mmHg, 95% CI, -9.1 to 3.5 mmHg) or DBP (X̅, 2.8 mmHg, 95% CI, -3.4 to 5.2 mmHg). The 95% prediction interval for true IIRD was - 11.9 to 8.4 mmHg for SBP and - 5.8 to 7.0 mmHg for DBP. CONCLUSIONS: While qigong is associated with reductions in resting SBP and DBP in adults with essential hypertension, a lack of true IIRD exists, suggesting that other external factors are responsible for any variation.

Efficacy of aerobic exercise and a prudent diet for improving selected lipids and lipoproteins in adults: a meta-analysis of randomized controlled trials.

BACKGROUND: Studies addressing the effects of aerobic exercise and a prudent diet on lipid and lipoprotein concentrations in adults have reached conflicting conclusions. The purpose of this study was to determine the effects of aerobic exercise combined with a prudent diet on lipid and lipoprotein concentrations in adults. METHODS: Studies were located by searching nine electronic databases, cross-referencing, and expert review. Two independent reviewers selected studies that met the following criteria: (1) randomized controlled trials, (2) aerobic exercise combined with diet recommendations (saturated/trans fat intake less than 10% of total calories and cholesterol less than 300 mg/day and/or fiber intake ≥ 25 g/day in women and ≥ 35 grams per day in men), (3) intervention ≥ 4 weeks, (4) humans ≥ 18 years of age, (5) published studies, including dissertations and Master's theses, (6) studies published in any language, (7) studies published between January 1, 1955 and May 1, 2009, (8) assessment of one or more of the following lipid and lipoprotein concentrations: total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), ratio of TC to HDL-C, non-HDL-C, low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG). Two reviewers independently extracted all data. Random-effects models that account for heterogeneity and 95% confidence intervals were used to pool findings. RESULTS: Of the 1,401 citations reviewed, six studies representing 16 groups (8 intervention, 8 control) and up to 559 men and women (282 intervention, 277 control) met the criteria for analysis. Statistically significant intervention minus control reductions were found for TC (-15.5 mg/dl, 95% CI, -20.3 to -10.7), TC:HDL-C (-0.4 mg/dl, 95% CI, -0.7 to -0.2), LDL-C (-9.2 mg/dl, 95% CI, -12.7 to -5.8) and TG (-10.6 mg/dl, 95% CI, -17.2 to -4.0) but not HDL-C (-0.5 mg/dl, 95% CI, -4.0 to 3.1). Changes were equivalent to reductions of 7.5%, 6.6%, 7.2% and 18.2% respectively, for TC, TC:HDL-C, LDL-C and TG. Because of missing variance statistics, non-HDL-C was excluded. CONCLUSIONS: Aerobic exercise combined with a prudent diet is highly efficacious for improving TC, TC:HDL-C, LDL-C and TG, but not HDL-C concentrations, in adults. However, additional studies are needed, including effectiveness studies using intention-to-treat analysis.

How Many US Children and Adolescents with Overweight and Obesity Could Improve Their Percent Body Fat by Exercising?: Meta-Analytic Based Estimates.

Background: Provide national estimates of the number of US children and adolescents with overweight and obesity who could improve their percent body fat by exercising. Methods: Data were derived from (1) a previous meta-analysis, (2) 2015-2016 prevalence data from the National Health and Nutrition Examination Survey (NHANES), and (3) 2017 US Census population data. Multiplicative calculations were based on (1) number-needed-to treat data from a previous meta-analysis of the number of children with overweight and obesity who could reduce their percent body fat by participating in either aerobic, strength, or combined aerobic and strength training, (2) 2015-2016 NHANES data on the prevalence of children and adolescents with overweight or obesity, and (3) 2017 US Census population data on children and adolescents 2-19 years of age. Results: For both children and adolescents with overweight or obesity, the number who could improve their percent body fat was estimated at 4,388,273 [95% confidence interval (CI) 3,831,523-4,845,023] for either aerobic or strength exercise and 6,507,410 (95% CI 5,744,285-7,267,534) for combined aerobic and strength exercise. Conclusions: A large number of US children and adolescents with overweight and obesity could improve their percent body fat by exercising.

Inter-individual differences in body mass index were not observed as a result of aerobic exercise in children and adolescents with overweight and obesity.

BACKGROUND: Exercise has been recommended as an important intervention for reducing adiposity in children and adolescents with overweight and obesity. OBJECTIVE: Determine whether inter-individual differences exist in relation to exercise-induced changes in adiposity among children and adolescents with overweight and obesity. METHODS: Meta-analysis of randomized controlled aerobic exercise trials and body mass index (BMI) in kg · m-2 . Change outcome standard deviations were pooled using the inverse-variance heterogeneity model. RESULTS: Twenty-eight studies (1185 participants) were included. Inter-individual differences in BMI were -0.1 (95% compatibility interval, -0.7 to 0.7). The 95% prediction interval for inter-individual responses in a future study was -2.9 to 2.9. The probability of a clinically meaningful difference in variability was 29% (possibly clinically important) in favour of controls vs exercisers. CONCLUSIONS: Inter-individual differences for BMI in kg · m-2 were not observed as a result of aerobic exercise in children and adolescents with overweight and obesity.