Urban Park Development and Pediatric Obesity Rates: A Quasi-Experiment Using Electronic Health Record Data.

INTRODUCTION: Childhood obesity affects ~20% of children in the United States. Environmental influences, such as parks, are linked with increased physical activity (PA). OBJECTIVE: To examine whether changes in Body Mass Index (BMI) z-score were associated with construction of a new park. METHODS: A quasi-experimental design was used to determine whether living in proximity of a park was associated with a reduction in BMI z-score. Children were selected from health clinics within an 11 mile radius of the park. A repeated-measure ANOVA was employed for analysis of the relationship between exposure (new park) and BMI z-score. RESULTS: Participants were 1443 (median age 10.3 range (2-17.9 years), BMI: z-score 0.84 ± 1.09) African American (77.4%) adolescents. Change in BMI z-score was not statistically different for children living at different distances from the park after controlling for age, gender, race, ethnicity, or payer type (p = 0.4482). We did observe a small 0.03 increase in BMI z-score from pre- to post-park (p = 0.0007). There was a significant positive association between child's baseline age and BMI z-score (p < 0.001). CONCLUSIONS: This study found proximity to a park was not associated with reductions in BMI z-score. Additional efforts to understand the complex relationship between park proximity, access, and PA are warranted.

Common scientific and statistical errors in obesity research.

This review identifies 10 common errors and problems in the statistical analysis, design, interpretation, and reporting of obesity research and discuss how they can be avoided. The 10 topics are: 1) misinterpretation of statistical significance, 2) inappropriate testing against baseline values, 3) excessive and undisclosed multiple testing and "P-value hacking," 4) mishandling of clustering in cluster randomized trials, 5) misconceptions about nonparametric tests, 6) mishandling of missing data, 7) miscalculation of effect sizes, 8) ignoring regression to the mean, 9) ignoring confirmation bias, and 10) insufficient statistical reporting. It is hoped that discussion of these errors can improve the quality of obesity research by helping researchers to implement proper statistical practice and to know when to seek the help of a statistician.

Systolic blood pressure response after high-intensity interval exercise is independently related to decreased small arterial elasticity in normotensive African American women.

Aerobic exercise transiently lowers blood pressure. However, limited research has concurrently evaluated blood pressure and small arterial elasticity (SAE), an index of endothelial function, among African American (AA) and European American (EA) women the morning after (i.e., ≈22 h later) acute bouts of moderate-intensity continuous (MIC) and high-intensity interval (HII) exercise matched for total work. Because of greater gradients of shear stress, it was hypothesized that HII exercise would elicit a greater reduction in systolic blood pressure (SBP) compared to MIC exercise. After baseline, 22 AA and EA women initiated aerobic exercise training 3 times/week. Beginning at week 8, three follow-up assessments were conducted over the next 8 weeks at random to measure resting blood pressure and SAE. In total all participants completed 16 weeks of training. Follow-up evaluations were made: (i) in the trained state (TS; 8-16 weeks of aerobic training); (ii) ≈22 h after an acute bout of MIC exercise; and (iii) ≈22 h after an acute bout of HII exercise. Among AAs, the acute bout of HII exercise incited a significant increase in SBP (mm Hg) (TS, 121 ± 14 versus HII, 128 ± 14; p = 0.01) whereas responses (TS, 116 ± 12 versus HII, 113 ± 9; p = 0.34) did not differ in EAs. After adjusting for race, changes in SAE were associated (partial r = -0.533; p = 0.01) with changes in SBP following HII exercise. These data demonstrate an acute, unaccustomed bout of HII exercise produces physiological perturbations resulting in a significant increase in SBP that are independently associated with decreased SAE among AA women, but not EA women.

Regression to the Mean: A Commonly Overlooked and Misunderstood Factor Leading to Unjustified Conclusions in Pediatric Obesity Research.

OBJECTIVE: In this paper we discuss what regression to the mean (RTM) is, the magnitude of RTM in realistic situations, interpretation of RTM, and recommendations for how to address RTM in study design. METHODS: Public health research faces many challenges in conducting gold standard randomized, controlled trials (RCT). Although there are many threats to validity in uncontrolled trials, RTM is often overlooked or not adequately considered. RTM is a statistical phenomenon that occurs with any pair of variables that have a correlation not equal to |1.0|. With RTM, subjects' average values on an outcome variable (e.g., BMI) change in a systematic direction over time despite there being no treatment effect. Without a proper control group, changes thought to be associated with an intervention may be due entirely to RTM. Investigators may draw erroneous conclusions based on results showing greater declines in a variable among participants with higher baseline of that variable compared to those with lower baseline of that variable, and label this evidence for differential treatment efficacy. CONCLUSIONS: Ignoring RTM can lead to unsubstantiated conclusions about the effects of treatments. These conclusions can lead to the waste of time, money, and other resources, which distract from finding appropriate interventions. When a true RCT design is not feasible, reasonable design alternatives involving nonrandomized control groups should be implemented.

Calorie restriction in overweight older adults: Do benefits exceed potential risks?

The evidence regarding recommendations of calorie restriction as part of a comprehensive lifestyle intervention to promote weight loss in obese older adults has remained equivocal for more than a decade. The older adult population is the fastest growing segment of the US population and a greater proportion of them are entering old age obese. These older adults require treatments based on solid evidence. Therefore the purpose of this review is three-fold: 1) to provide a more current status of the knowledge regarding recommendations of calorie restriction as part of a comprehensive lifestyle intervention to promote weight loss in obese older adults, 2) to determine what benefits and/or risks calorie restriction adds to exercise interventions in obese older adults, and 3) to consider not only outcomes related to changes in body composition, bone health, cardiometabolic disease risk, markers of inflammation, and physical function, but, also patient-centered outcomes that evaluate changes in cognitive status, quality of life, out-of-pocket costs, and mortality. Seven randomized controlled trials were identified that examined calorie restriction while controlling for exercise intervention effects. Overall, the studies found that calorie restriction combined with exercise is effective for weight loss. Evidence was mixed regarding other outcomes. The risk-benefit ratio regarding calorie restriction in older adults remains uncertain. Greater long-term follow-up is necessary, and complementary effectiveness studies are needed to identify strategies currently used by obese older adults in community settings.

Cultural beliefs and physical activity among African-American adolescents.

OBJECTIVE: To examine the association of cultural beliefs with physical activity (PA) among African-American adolescents. METHODS: For a list of 42 leisure-time physical activities, adolescents (N = 116) indicated whether they believed the activity was 'Mostly a Black Thing', 'Equally a Black and White Thing', or 'Mostly a White Thing'. Moderate-to-vigorous physical activity was assessed using accelerometers. RESULTS: Participants scoring in the highest quartile of Mostly Black score engaged in more PA and were less likely to be overweight or obese compared to those in lower quartiles. However, these findings were not statistically significant. CONCLUSION: Further research to validate the association of cultural beliefs with PA is needed to inform health-enhancing PA interventions for this population.

Methodological quality of meta-analyses on the blood pressure response to exercise: a review.

Numerous meta-analyses have been conducted to summarize the growing numbers of trials addressing the effects of exercise on blood pressure (BP), yet it is unclear how well they have satisfied contemporary methodological standards. We applied an augmented version of the Assessment of Multiple Systematic Reviews (AMSTARExBP) scale to 33 meta-analyses retrieved from searches of electronic databases. Qualifying reports used meta-analytic procedures; examined controlled exercise training trials; had BP as a primary outcome; and had exercise or physical activity interventions independently or combined with other lifestyle interventions. AMSTARExBP scores averaged near the middle of the scale (Mean = 56.0% ±â€Š21.4% of total items possible); co-authored and more recent meta-analyses had higher quality scores. Common deficits were failures to disclose full search details (30% did), gauge the quality of included trials (48% did), use duplicate study selection and data extraction (55% did), or incorporate study quality in formulating results (35% did). Nearly all (91%) meta-analyses observed that exercise significantly lowered BP; fewer (58%) found that such effects depended on exercise or patient characteristics but these patterns often conflicted. Meta-analyses are often pillars of clinical recommendations and guidelines, yet only 58% addressed the clinical translations of their findings. In sum, meta-analyses have contributed less than ideally to our understanding of how exercise may impact BP, or how these BP effects may be moderated by patient or exercise characteristics. Future meta-analyses that better satisfy contemporary standards offer considerable promise to understand how and for whom exercise impacts BP.

Effect of zoledronic acid on bone density and markers of bone turnover in a community clinic.

OBJECTIVE: This study aims to document the efficacy of zoledronic acid by comparing bone densities and markers of bone turnover, in patients with osteoporosis. METHODS: Bone mineral density (BMD) and urinary N-telopeptide, a marker of bone turnover, were compared before and after treatment with intravenous zoledronic acid. RESULTS: 52 participants had atleast two doses of zoledronic acid over 36 months. Significant increases in BMD were found in the spine (t=4.38, P<0.01) and decrease in bone turnover marker N-telopeptide (t=3.30, P=0.002). Small but significant correlations were determined between prior steroid use and change in BMD in the spine (r=0.35, P<0.05), and family history of osteoporosis and change in BMD in the right femur (r=0.38, P<0.05). CONCLUSION: Annual infusions of zoledronic acid for at least two years, revealed a significant increase in bone density at the spine and a decrease in urinary N-telopeptide in patients treated at our center.