abstract: College students are a niche of young adults, characterized by abnormal sleeping habits and inactive lifestyles. Many students entering college are as young as 18 years old and graduate by 22 years old, a window of time in which their bones are still accruing mineral. The purpose of this cross-sectional study was to determine whether sleep patterns and physical activity observed in college students (N= 52) 18-25 years old at Arizona State University influenced bone biomarkers, osteocalcin (OC) and N-terminal telopeptide of type 1 collagen (NTX-1) concentrations. Students completed various dietary and health history questionnaires including the International Physical Activity Questionnaire short form. Students wore an actigraphy watch for 7 consecutive nights to record sleep events including total sleep time, sleep onset latency and wake after sleep onset. Total sleep time had a significant, negative correlation with OC (r = -0.298, p-value =0.036) while sleep onset latency had a significant, positive correlation with NTX-1 serum concentration (r = 0.293, p-value = 0.037). Despite correlational findings, only sleep percent was found to be significant (beta coefficient = 0.271 p-value = 0.788) among all the sleep components assessed, after adjusting for gender, race, BMI and calcium intake in multivariate regression models. Physical activity alone was not associated with either bone biomarker. Physical activity*sleep onset latency interactions were significantly correlated with osteocalcin (r = 0.308, p-value =0.006) and NTX-1 (r = 0.286, p-value = 0.042) serum concentrations. Sleep percent*physical activity interactions were significantly correlated with osteocalcin (r = 0.280, p-value = 0.049) but not with NTX-1 serum concentrations. Interaction effects were no longer significant after adjusting for covariates in the regression models. While sleep percent was a significant component in the regression model for NTX-1, it was not clinically significant. Overall, sleep patterns and physical activity did not explain OC and NTX-1 serum concentrations in college students 18-25 years old. Future studies may need to consider objective physical activity devices including accelerometers to measure activity levels. At this time, college students should review sleep and physical activity recommendations to ensure optimal healthy habits are practiced. / Dissertation/Thesis / Masters Thesis Nutrition 2019

Short sleep duration in childhood has been associated with an increased risk of overweight and obesity. Research suggests that physical activity might mediate this association; however, studies examining associations between physical activity and sleep in young children have reported equivocal findings. A possible explanation for these inconsistencies is that past studies have looked at total physical activity counts rather than examining physical activity regularity. We aim to explore the relationship of regular physical activity, sedentary behavior, and sleep in preschoolers and kindergartners. 131 children (ages 4-6) were included in this study. Each child wore a waist-worn accelerometer for three days and three nights. Waist-worn accelerometers reliably measure sleep and physical activity in children. Associations of regular physical activity, sedentary behavior, and sufficient sleep were determined using logistic regression models. There was no association between the number of days that children engaged in physical activity (≥ 60 minutes) and sufficient sleep. Further, there was no association between the number of days that children engaged in ≥ 20 minutes of vigorous activity and sufficient sleep. Children who engaged in minimal sedentary activity had greater odds of obtaining sufficient sleep as compared to children who engaged in more sedentary activity.

Background: It is well established throughout the literature that regularly engaging in physical activity throughout pregnancy is associated with optimized health outcomes for both the mother and the fetus. The mediators and mechanistic pathways through which these observed exercise-induced outcomes are achieved are largely unknown. This thesis attempts to address this gap in knowledge. Methods: The objective of the first study was to develop an exercise protocol based on the recommendations from the ‘2019 Canadian guideline for physical activity throughout pregnancy’ and to subsequently evaluate the myokine response post-exercise. Pregnant (n=13) and non-pregnant (n=17) women performed a moderate-intensity bout of treadmill walking following which pre- and post-exercise serum for a panel of ten well-characterized myokines was analyzed. The objective of the second study was to evaluate whether acute and/or chronic exercise elicited changes in metrics of placental growth and development – thereby proposing possible mechanisms through which physical activity may be conferring health benefits to the fetus. Serum (pre- and post-exercise) collected from the first study was used to treat placental cell lines to assess the effect of acute exercise on cellular proliferation as well as nutrient transporter (GLUT1, SNAT1, FATP4) expression and localization. Term placental tissue collected from active (n=10) and non-active (n=10) participants in the PLACENTA study were used to evaluate the role of chronic exercise on changes in nutrient transporter (GLUT1, SNAT1, FATP4) expression and localization. Results: Pregnant women from the first study exhibited higher levels of four myokines post- versus pre-exercise: FGF21, EPO, BDNF and IL-15. As for the second study, BeWo cell lines treated with serum collected from pregnant women yielded higher GLUT1 expression compared to non-pregnant serum, independently of exercise. Lastly, FATP4 expression was found to be higher in term placentas of active compared to non-active pregnant women. Conclusion: This thesis identified four myokines that are elevated in the serum of pregnant women following a bout of acute exercise. The role of these myokines in pregnancy remains to be elucidated. Further, chronic and acute exercise are shown to alter expression of key placental macronutrient transporters.

Childhood obesity is a worldwide epidemic. In the United States, approximately 17% of adolescents are obese; and 13% of the general population is overweight. Obese adolescents are at threefold risk for developing chronic health conditions in adulthood, including type II diabetes, hypertension, and heart disease. The purpose of this project was to evaluate the results of a quality improvement program to reduce adolescent obesity as measured by BMI 5% over 18 months in a rural health primary care clinic. The health belief model and theory of planned behavior guided the project as adolescents need to first understand the risks associated with obesity and the benefits derived from a healthier lifestyle Then, they can be prepared to engage in regular exercise and good eating behaviors. A convenience sample of 100 adolescents was randomly assigned to an intervention group with structured physical activity regimen and dietary education classes and a standard care group with normal counseling. Two separate one-sided t tests with 90% confidence intervals were used to analyze the data. Also, run charts were constructed to assess the effectiveness of the program. The result of the t test revealed the weight for the intervention group at 18 months (M = 42.85, SD = 0.79) was significantly lower than it was for those in the non-intervention group (M = 45.06, SD = 0.59), t(36) = -9.79, p < 0.01. Furthermore, the run charts demonstrate the average BMI for those in the interventional group steadily decreased over 18 months while the non-intervention group steadily increased. Positive social change was achieved at the organization level as adolescent obesity was reduced with the evidence-based interventions. This project serves as a potential model for replication in other rural health primary care clinics.

There are few data available regarding the relationship between physical activity and veteran status in those with combined chronic obstructive pulmonary disease (COPD) and obesity. COPD is a common illness and a leading cause of death in the United States. Veterans represent a distinct subpopulation in the United States and are more likely to have COPD, which is a disease with a high rate of comorbidities such as obesity. Physical activity can improve outcomes for those with COPD and obesity. However, recommendations for physical activity for those with COPD and obesity are vague. This study, based on the self-determination theory, sought to explore the relationship between average weekly physical activity and veteran status while controlling for age, sex, race, ethnicity, smoking status, body mass index (BMI), education level, and annual household income in those with comorbid COPD and obesity. Also, the relationship between not meeting, meeting, and exceeding physical activity recommendations and veteran status, while accounting for variation in for age, sex, race, ethnicity, smoking status, BMI, education level, and annual household income, was explored. A case-control study was done to answer the research questions using multiple regression and ordinal regression analyses, respectively, using data from 1,430 participants from the 2015 BRFSS. Veteran status was not significantly associated with physical activity nor was it significantly associated with falling below, at, or above recommended physical activity amounts. However, it was found that increased BMI was associated with decreased physical activity. The results from this study can be used to inform policies, refine recommendations, and guide interventions for those with COPD and obesity.

Rural adults engage in less physical activity and are less likely to meet activity recommendations than urban or suburban adults. Understanding determinants of this behavior can help design interventions for increasing activity levels. This series of studies examined the perceived determinants of physical activity in the social, physical, and policy environments of rural adults, using the following aims: Aim 1: A secondary analysis was conducted of a cross-sectional survey among 407 adults from two rural towns to examine determinants of physical activity separately by the domain in which this behavior occurs (i.e. home care, active living, etc.). Multiple regression analyses found that social characteristics (such as support from friends), policy attitudes (such as workplace incentives for exercise), and physical environmental factors (such as an activity-friendly neighborhood) were positively associated with total physical activity, active living, and sport. Barriers were negatively associated with these domains. No factors were associated with physical activity in work or home care. Physical activity determinants are specific to the domain of physical activity, and more research needs to be done to determine factors associated with physical activity in home or work. Aim 2: Measurement tools should be culturally relevant to a specific population for accurate measurement. Three focus groups were conducted (n=19) in a rural Midwestern county to tailor existing measurement tools to this population. Focus group members were asked about the activities they engaged in and facilitators and barriers to those activities. Important factors associated with physical activity include social support and modeling active behavior. Focus group members desired to see community buildings be open to the public for exercise. This study revealed contextual issues and cultural language for tailoring physical activity measurement tools for rural adults. Aim 3: Ecological models propose that the environment impacts behavior on several different levels. Using a tailored survey instrument, this study examined social, environmental, and policy-level determinants of physical activity at different levels of an ecological approach. A cross-sectional survey was given to 143 individuals residing in a rural Midwestern county. Test-retest reliability was examined using correlations and kappa statistics, and was found to be very good to substantial. Multiple regression analyses were conducted using general linear modeling. Social factors were associated with total physical activity; environmental factors were associated with active transport, house and yard work, vigorous activity, and walking; and policy factors were associated with physical activity at work, and moderate-intensity activity. Findings can be used to tailor physical activity interventions using an ecological approach in rural adults, based on the specific domain and intensity in which the activity occurs. These studies provide insight into the contextual factors that are associated with physical activity in rural Midwestern adults, and provide evidence that determinants should be examined and presented by the domain and intensity in which this behavior occurs. It is clear that social and physical environments and policy attitudes are associated with domain- and intensity-specific physical activity in this population.

Levels of participation in physical activity and sport by the New Zealand population are in decline, whilst the levels of sedentary behaviours are rising. Developing positive physical activity experiences, perceptions and habits in childhood may provide an effective approach to decrease the burden of inactivity. The purpose of this thesis was to improve knowledge of the efficacy of a sport-based intervention to increase physical activity levels of New Zealand children from a low socio-economic background. This was achieved by implementing an after-school soccer intervention at two low decile schools in Auckland, New Zealand. To determine current levels of physical activity, fifty-eight children wore a NL-2000 pedometer for four consecutive days (three weekdays and one weekend). Mean step counts (± SD) for boys were 17018 (± 4640) and for girls 12415 (± 4329) on weekdays, and for boys 12507 (± 4338) and girls 9537 (± 4421) on weekends. Nearly 50% of girls and 37% of boys were not reaching previously published daily step count recommendations of 15,000 for boys and 12,000 for girls during weekdays. The feasibility and efficacy of a six-week after-school soccer programme (2/hr.wk-1) on physical activity levels of 70 children (43 boys, 27 girls) compared to a control group of 25 children (23 boys, 2 girls) was determined in a randomised controlled trial. Measures of physical activity (4 day sealed pedometry), mass and height were completed at baseline, Week 6 (end of the intervention), and at three-month post-intervention. Compared to control, participants in the soccer programme attained higher weekday step counts after 6 weeks (treatment 16980 ± 4515; control 15021 ± 3783) and these were sustained three months post-intervention (treatment 16218 ± 4591; control 14591 ± 3488). However, these step count differences were not statistically significant. When children were grouped into activity tertiles (low, moderate and highly active) the intervention effect was more evident in the low to moderately active children. Further analysis revealed that the treatment groups’ moderate activity tertile was significantly more active than the control at follow up (p = 0.0399). This programme may offer a viable alternative to traditional physical activity interventions which concentrate on other forms of physical activity accumulation such as active transport and physical education. However, additional research needs to be carried out to determine whether the absence of statistical differences is simply a lack of statistical power.

Improving physical activity (PA) participation is a public health priority in developed and developing countries to curb the substantial and growing prevalence of lifestyle-related diseases. Early childhood may be an especially important time to encourage PA; however, there is a paucity of research in this area. The aim of this research was to contribute to the limited body of work in PA in early childhood by investigating PA measurement approaches in young children and applying this knowledge to determine socio-environmental associations of preschool PA. An initial literature review provided the background for the thesis and determined the approaches taken in the ensuing chapters. A second literature review provided a detailed critique of research specific to PA measurement in early childhood to further inform the empirical studies. Information for the empirical chapters was drawn from three research projects: two studies were completed that assessed tools for objectively measuring PA in young children (pedometers and accelerometers), and these studies informed a final project to quantify associates of PA in a sample of preschool-aged children. Novel and important findings from the preliminary studies were that pedometer accuracy for measuring free-living PA and walking in children aged 3-5 years was poor, especially for pedometers worn at the back of the child, or during slow walking. Furthermore, when investigating the utility of accelerometers (more complex and frequently adopted tools) to quantify PA intensity in preschoolers, their application and use of commonly employed thresholds resulted in systematic underestimation of PA intensity and poor agreement (=0.09) when compared with a direct observation criterion measure. Application of existing accelerometer thresholds to classify PA intensity in preschoolers was therefore likely to yield biased estimates. Given the dearth of robust alternatives, a novel approach was developed to calculate individual activity rates from the raw accelerometer data. To account for over-dispersion in accelerometer counts, daily average activity rates per second were derived for each participant using negative binomial generalised estimating equation (GEE) models with a first-order autoregressive (AR1) correlation structure. These rates were assumed to be exchangeable between days and normally distributed. Potential socio-environmental associates of children’s activity rates and body size were thus assessed using normal GEE models with exchangeable correlation structures. Parental PA and child age were independently and significantly associated with child activity rates (P≤0.04). No relationships between child body size and PA or television (TV) exposure were found. Common approaches to PA measurement and data consideration were challenged in this research and novel robust methods devised utilising contemporary statistical methods. Accelerometer data can be successfully reduced to individual activity rates to mitigate current issues related to objective PA quantification with preschoolers. Parental involvement in preschool PA interventions is worthy of further investigation, and younger children may stand to benefit more from increased activity. Further exploration of the complex interactions between PA, exposure to media, and health outcomes in preschool-aged children is warranted.

Environments that support physical activity (PA) engagement are now seen as an important part of the solution for accumulating daily physical activity which confers health benefits, particularly transport-related PA (TPA). Despite this recognition, understanding the determinants of health-related PA has traditionally focused on identifying associations between the social environment and non-specific PA domains. As such, prior to commencing this thesis little was known about the relationships between the built environment and overall PA engagement within the New Zealand context. Little was also known about associations between TPA attitudes and behaviours, and urban design. This research sought to overcome this paucity of knowledge by investigating associations between overall PA and TPA engagement and perceptions, health outcomes, urban design, and socio-demographic variables from a public health perspective. The body of research was initiated with two literature reviews that formed the context for the following six empirical chapters. Data in the empirical chapters were drawn from three self-report surveys using adult samples. The research commenced by examining associations between urban design and overall PA engagement, and then narrowed towards TPA-specific relationships. TPA relationships were identified through the development and implementation of a reliable survey that captured associated behaviours and attitudes. Several new findings were drawn from this body of work. Overall, 21% of adults recognised they could replace automobile journeys on at least two days per week, and walking was deemed an acceptable travel alternative. Adult TPA engagement levels were low; 7% commuted to place of work/study and 32% travelled to the convenience shop by TPA modes. Furthermore, when compared with those who commuted to an occupation by TPA, respondents who used motorised travel were less likely to be classified as active (odds ratio (OR)=0.5) and be of normal body mass index (OR=0.5). No significant health relationships existed for convenience shop travel. As well, 4% of adults reported no automobile availability. When this group was compared with those with unrestricted automobile availability, they were less likely to be classified as active (OR=0.3), but were more likely to engage in TPA modes to access destinations (occupation, OR=6.3; convenience shop, OR=9.8). Occupation-related commute distances also revealed interesting findings. Overall, 50% of respondents perceived they could, and 10% of the sample actually did, commute by TPA modes for distances less than five kilometres, and relationships were strongly mediated by distance. Other urban design variables were objectively assessed with TPA engagement for occupation-related commute distances less than five kilometres. Those who travelled along the most connected street networks were more likely to engage in TPA modes (OR=6.9) when compared with respondents travelling along the least connected networks. No relationships were found with other urban design variables and TPA engagement.This research substantially contributes to this research area by identifying associations between overall PA and TPA engagement and perceptions with urban design. It is likely that shifting the perceptions of adults who recognise they can employ TPA modes, into actual TPA engagement will result in promising population health gains. Future PA initiatives with adults should consider promoting walking for transport as a sustainable solution. A lack of TPA interventions is evident; however, methodological issues need to be resolved before developing such initiatives. Although strategies aimed towards changing perceptions may be valuable for future TPA interventions, it is likely macro-scale urban design modifications (e.g., improved job-housing balance, highly-grained street networks) and legislation (e.g., automobile restrictions) will have the greatest success for increasing TPA engagement in the adult population.

[Truncated abstract] The Dogs and Physical Activity (DAPA) study sought to examine the relationship between dog ownership and physical activity, in particular walking. It used an ecological model to examine the socio-demographic, intrapersonal, social environmental, physical environmental and policy-related factors affecting dog owners walking with their dog. Results from this study are presented as a series of papers four which are published, in press or accepted for publication. A review of the dog ownership, health and physical activity literature and results from qualitative research of the potential barriers and motivators to dog owners being physically active with their dogs were used to develop and test an instrument for measuring dog walking behaviour. The DAPA tool was designed to measure the amount of physical activity people undertake with their dog and dog-specific individual and environmental factors affecting people walking with their dog. It was developed as a supplementary tool for the second RESIDential Environments (RESIDE) survey. RESIDE is a 5-year longitudinal study of the physical activity levels of people building homes in new housing estates in Western Australia. Findings from the baseline survey of 1813 RESIDE participants (44% dog owners) showed that dog owners were 60% more likely than non-owners to achieve sufficient physical activity and sufficient walking and almost 80% more likely than non-owners to achieve sufficient walking for recreation in the neighbourhood after controlling for demographic, intrapersonal and environmental differences. ... Findings from the DAPA study highlight the importance of the local policy and physical environment in encouraging dog walking behaviour. Perceived lack of accessible public open space (POS) and dogspecific exercise areas were identified by focus group participants as major barriers to dog owners walking with their dog. Objective measurement of the local physical environment of dog owners supported their concerns; no dog owners in this study had access to a sign-posted off-leash park [greater than or equal to] 2 acres within their neighbourhood. Furthermore, access to local POS with dog-supportive infrastructure was associated with being a regular dog walker. Overall, the results of this study draw attention to the needs of dog owners in the allocation and design of POS. The prospective component of the DAPA study enabled examination of the causal relationship between dog ownership and physical activity. After adjusting for baseline variables, dog acquisition significantly increased minutes of recreational walking within the neighbourhood by 37 minutes. However, after further adjustment for changes in baseline variables, the increase in minutes of recreational walking within the neighbourhood from dog acquisition reduced to 21 minutes and was no longer statistically significant. Increase in intention to walk appeared to mediate the relationship between dog acquisition and increased recreational walking. This study highlights a number of important physical activity benefits associated with dog ownership and provides evidence to suggest that dog walking has the potential to positively affect the proportion of the community who are sufficiently active.