Hyo Lee

Benefits and environmental determinants of physical activity in children and adolescents.

In this review, we identify the health benefits associated with physical activity (PA); address the physical activity and sedentary guidelines issued by public health scientists as well as children’s compliance to these guidelines; discuss the importance of motor skill acquisition during early childhood; and identify different settings that contribute to physical activity participation and strategies for improving PA in these settings. Results show that regular participation in PA during childhood has numerous immediate benefits, including positive changes in adiposity, skeletal health, psychological health, and cardiorespiratory fitness. Additionally, motor skill development during early childhood may have immediate health benefits as well as long-lasting effects in adulthood. Furthermore, the benefits of PA during childhood also appear to positively influence adult health outcomes, such as increased bone mineral density. Key environmental settings that have been shown to influence children’s PA behavior include child care, active commuting to and from school, school recess, school physical education, after-school programs, churches, medical settings, and the home environment. Recommendations for practitioners and researchers are discussed.

Molecular origins of surfactant- mediated stabilization of protein

Loss of activity through aggregation and surface-induced denaturation is a significant problem in the production, formulation and administration of therapeutic proteins. Surfactants are commonly used in upstream and downstream processing and drug formulation. However, the effectiveness of a surfactant strongly depends on its mechanism(s) of action and properties of the protein and interfaces. Surfactants can modulate adsorption loss and aggregation by coating interfaces and/or participating in protein-surfactant associations. Minimizing protein loss from colloidal and interfacial interaction requires a fundamental understanding of the molecular factors underlying surfactant effectiveness and mechanism. These concepts provide direction for improvements in the manufacture and finishing of therapeutic proteins. We summarize the roles of surfactants, proteins, and surfactant-protein complexes in modulating interfacial behavior and aggregation. These events depend on surfactant properties that may be quantified using a thermodynamic model, to provide physical/chemical direction for surfactant selection or design, and to effectively reduce aggregation and adsorption loss.

The Relationship of Actigraph Accelerometer Cut-Points for Estimating Physical Activity with Selected Health Outcomes: Results from NHANES 2003-06.

The purpose of this study was to examine the influence of child and adult cut-points on physical activity (PA) intensity, the prevalence of meeting PA guidelines, and association with selected health outcomes. Participants (6,578 adults ≥ 18 years, and 3,174 children and adolescents ≤ 17 years) from the National Health and Nutrition Examination Survey 2003–06 (Centers for Disease Control and Prevention, 2006) wore an accelerometer for 7 days. PA intensity was estimated with 5 child-derived and 12 adultderived cut-points. For all, the cut-point influenced PA intensity and the prevalence of meeting PA guidelines. Similarly, cut-point selection influenced the relationship between physical activity and various health outcomes. Future research should further enhance meaningful cut-points relevant to populations with diverse health and age profiles.

Evidence to Support Including Lifestyle Light-Intensity Recommendations in Physical Activity Guidelines for Older Adults

Purpose. The purpose of this study was to examine the association of objectively measured lifestyle light-intensity physical activity (LLPA) and moderate-to-vigorous physical activity (MVPA) with various biological markers and chronic diseases among a nationally representative sample of U.S. older adults (65+ years). Design. A cross-sectional design was used for this study. Setting. Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 2003–2006. Subjects. Subjects were 1,496 older U.S. adults. Measures. Participants wore an accelerometer for at least 4 days and completed questionnaires to assess sociodemographics and chronic disease information. Blood samples were taken to assess biological markers. Analysis. Adjusted Wald tests and Poisson regression were used to examine the association of LLPA and MVPA with biological markers and chronic disease. Results. Older adults engaging in ≥300 min/wk of LLPA had lower observed values for body mass index, waist circumference, C-reactive protein, and insulin resistance compared to those engaging in <300 min/wk of LLPA. Additionally, those engaging in <300 min/wk of LLPA had a rate 1.18 times greater for having chronic disease compared to those engaging in ≥300 min/wk of LLPA. Conclusion. In this national sample of older U.S. adults, participation in at least 300 min/wk of LLPA was associated with more favorable health outcomes. Future experimental studies are warranted to confirm these findings.

Association Between Physical Activity and Inflammatory Markers Among U.S. Adults With Chronic Obstructive Pulmonary Disease

Purpose. Chronic obstructive pulmonary disease (COPD) may cause not only inflammation in the lungs but also systemic effects. One potential strategy to reduce systemic inflammation and attenuate disease progression is physical activity (PA). However, no nationally representative studies, to our knowledge, have examined the association between objectively measured physical activity and inflammation among those with COPD. Design. Cross-sectional. Setting. National Health and Nutrition Examination Survey 2003–2006. Subjects. Two hundred thirty-eight former or current smokers with self-reported COPD who had complete data on study variables. Measures. Participants wore an accelerometer for ≥4 days to assess light-intensity PA (LPA), moderate-to-vigorous PA (MVPA), and total physical activity (TPA); completed questionnaires to assess self-reported COPD and smoking status; and had their blood taken to assess white blood cell (WBC) and neutrophil levels. Analysis. Multivariable linear regression analysis was used. Results. LPA (β = –.0004), MVPA (β = –.04), and TPA (β = –.0004) were significantly inversely associated with WBC level. Similarly, LPA (β = –.001) and TPA (β = –.001) were significantly inversely associated with neutrophils; however, MVPA was marginally associated with neutrophils (β = –.05; p =.06). Conclusion. These analyses demonstrate an inverse association between objectively measured PA and inflammation among current or former smokers with COPD. If these findings are confirmed elsewhere, then PA among those with COPD may serve as an anti-inflammatory strategy to possibly decrease cardiovascular and metabolic disease occurrence.

Rationale for Promoting Physical Activity Among Cancer Survivors: Literature Review and Epidemiologic Examination

PURPOSE/OBJECTIVES To review the extant literature on the link between physical activity and health outcomes among cancer survivors; identify evidence-based strategies to promote physical activity among this population; and conduct an epidemiologic study based on gaps from the literature review, examining the association between physical activity and various biologic markers. DATA SOURCES The authors used PubMed and Google Scholar up to July 2013, as well as data from the 2003-2006 National Health and Nutrition Examination Survey for the empirical study. DATA SYNTHESIS Studies were examined through a systematic review process. In the epidemiologic study, 227 adult cancer survivors wore an accelerometer for four days or longer, with biologic markers (e.g., cholesterol) assessed from a blood sample. CONCLUSIONS The review study demonstrated that cancer survivors are relatively inactive, but physical activity may help to reduce the risk of cancer recurrence and cancer-related mortality, increase cancer treatment rates, reduce pain and other side effects associated with cancer treatment, and improve physical and mental health. The epidemiologic study showed that physical activity was associated with several understudied biomarkers (e.g., neutrophils, white blood cells) that are linked with cancer recurrence, cancer-related mortality, and other chronic diseases. IMPLICATIONS FOR NURSING Nurses are encouraged to promote physical activity in cancer survivors.

The "fit but fat" paradigm addressed using accelerometer-determined physical activity data.

Background: No studies have addressed the “fit but fat” paradigm using accelerometry data. Aim: The study was to determine if 1) higher levels of accelerometer-determined physical activity are favorably associated with biomarkers in overweight or obese persons (objective 1); and 2) overweight or obese individuals who are sufficiently active have better or similar biomarker levels than normal weight persons who are not sufficiently active (objective 2). Materials and Methods: Data from the 2003-2006 National Health and Nutrition Examination Survey were analyzed and included 5,146 participants aged 20-85 years. Results: Regarding objective 1, obese active individuals had more favorable waist circumference, C-reactive protein, white blood cells, and neutrophil levels when compared to obese inactive individuals; similar results were found for overweight adults. Regarding objective 2, there were no significant differences between normal weight inactive individuals and overweight active individuals for nearly all biomarkers. Similarly, there were no significant differences between normal weight inactive individuals and obese active individuals for white blood cells, neutrophils, low-density lipoprotein cholesterol, total cholesterol, triglycerides, glucose, or homocysteine. Conclusions: Physical activity has a protective effect on biomarkers in normal, overweight, and obese individuals, and overweight (not obese) active individuals have a similar cardiovascular profile than normal weight inactive individuals.

Daily movement patterns and biological markers among adults in the United States

OBJECTIVE To examine the combined effects of sedentary (SED), light (LPA) and moderate-to-vigorous physical activity (MVPA) on biological markers among a nationally representative sample of U.S. adults. METHODS Data from the 2003-2006 NHANES study was used, with 5580 adults (≥20years) included in the study. Participants wore an ActiGraph 7164 accelerometer with accelerometry data used to create four movement pattern groups: ≥150min/week of MVPA and LPA≥SED; ≥150min/week of MVPA and LPA<SED; <150min/week of MVPA but LPA≥SED; and <150min/week of MVPA and LPA<SED. Blood samples were taken to assess various biological parameters (e.g., cholesterol). RESULTS 47.2% (SE: 1.2) of Americans engaged in <150min/week of MVPA and had a negative LPA-SED balance. In general, participants who engaged in ≥150min/week of MVPA, regardless of LPA-SED balance, had more favorable biological levels; however, there was evidence showing that even if individuals engaged in <150min/week of MVPA, but if their LPA exceeded SED, they had more favorable levels of triglycerides and insulin. CONCLUSIONS Programs are needed to increase Americans engagement in MVPA, and also ensure that LPA exceeds SED behavior.

Dose Response Association between Physical Activity and Biological, Demographic, and Perceptions of Health Variables

Background: Few population-based studies have examined the association between physical activity (PA) and cardiovascular disease risk factors, demographic variables, and perceptions of health status, and we do not have a clear understanding of the dose-response relationship among these variables. Methods: Data from the 2003-2006 National Health and Nutrition Examination Survey was used to examine the dose-response relationship between objectively measured PA and metabolic syndrome (and its individual cardiovascular disease risk factors), demographic variables, and perceptions of health. After exclusions, 5,538 participants 18 years or older were included in the present study, with 2,538 participants providing fasting glucose and 2,527 providing fasting triglyceride data. PA was categorized into deciles. Results: Overall, the health benefits showed a general pattern of increase with each increasing levels of PA. Of the ten PA classifications examined, participants in the highest moderate-to-vigorous physical activity (MVPA) category (at least 71 min/day) had the lowest odds of developing metabolic syndrome. Conclusion: At a minimum, sedentary adults should strive to meet current PA guidelines (i.e., 150 min/week of MVPA), with additional positive benefits associated with engaging in three times this level of PA.

Parenting Practices as Mediators of Child Physical Activity and Weight Status

Understanding the environmental factors that influence children’s physical activity is an important prerequisite before effective physical activity interventions can be developed and implemented. Parenting is one environmental factor that has been empirically shown to positively influence children’s physical activity. However, in order to promote physical activity in children, a better understanding of how parents influence children’s physical activity behavior is required. Previously, Birch and Davison developed a model depicting parental factors hypothesized to influence child dietary behaviors. We extended this model by identifying parental factors hypothesized to promote physical activity in children. This review focuses on the mediational role that parenting practices and behaviors play in influencing child mediators of physical activity behavior, and, ultimately, weight status. Priorities for future research are discussed.