Preeclampsia is a leading cause of maternal and infant morbidity and mortality worldwide. For the first aim, a systematic literature review and meta-analysis was performed to examine the associations between maternal lipid concentrations during pregnancy (HDL-C, LDL-C, non-HDL-C, total cholesterol, and triglycerides) with subsequent risk of preeclampsia. Data from the Study of Pregnancy-induced Hypertension in Iowa, a population-based, case control study of preeclampsia and gestational hypertension, was used to address the other two aims: 1) elucidate the independent contribution of physical activity, an important modifier of dyslipidemia, on the risk of preeclampsia, and 2) to evaluate the association between the genetic susceptibility for dyslipidemia and the risk of preeclampsia. Published reports examining lipid levels during pregnancy and preeclampsia have been inconsistent. Meta-analyses demonstrated that preeclampsia was associated with elevated total cholesterol, non-HDL-C, and triglyceride levels, regardless of gestational age at time of blood draw, and lower levels of HDL-C in the third trimester. A marginal association was also found with LDL-C levels. Statistical heterogeneity was detected in all analyses. Physical activity has been hypothesized to reduce the risk of preeclampsia, but previous studies have had a range of limitations resulting in mostly suggestive, though nonsignificant findings. After adjustments, increasing levels of LTPA (trend, p=0.02) and increasing amounts of time spent active each day (trend, p=0.03) were significantly associated with a reduced risks of preeclampsia (trend, p=0.02). Increasing amounts of time spent sitting per day was marginally associated with the risk of preeclampsia (trend; p=0.10), and those women who were active an average of more than 8.25 hours per day had the most significantly reduced risk of preeclampsia (adjusted OR 0.58, 95% CI 0.36, 0.95). In examining the effects of a woman's genetic susceptibility to dyslipidemia as a risk factor for preeclampsia, we found that the more risk alleles a woman has for dyslipidemic levels of HDL-C, the greater her risk for developing preeclampsia. While this relationship was of marginal statistical significance, these results are suggestive of a relationship that may help elucidate the pathogenesis of preeclampsia. Our findings demonstrate the contribution of maternal lipid concentrations during pregnancy on preeclampsia risk, and suggest a behavioral modification that could help counter that increased risk. Additionally, implications of HDL-C genetics in preeclampsia risk identify potential genetic and biologic pathways to be explored in the pathogenesis of preeclampsia.

PURPOSE: To understand the influences of mechanical loading on bone adaptation, the ground reaction force (GRF) applied to the bone must be quantified. The use of force plates in a lab setting is the accepted method for quantifying GRFs; however, this is not feasible in free-living situations. Recent developments in accelerometer technology may provide the ability to evaluate the effects of mechanical loading on bone outside of laboratory settings. The purpose of this project was to validate an accelerometer for the measurement of mechanical loading by comparing its output against GRFs. METHODS: Male and female participants (n = 20 males, 20 females; 18 to 49 yr) completed 10 repetitions of 9 common everyday movements (stand, walk, jog, run, 15 cm jump, step down from curb, drop down from curb, forward hop, and side hop) on a force plate with an accelerometer worn on their right hip. Then, a subset (n = 5 males, 5 females) wore an accelerometer on their right hip and played basketball, volleyball, and dodgeball as a group. Finally, all 40 participants wore an accelerometer home for 7 days. All activities were organized into derived activity categories labeled as low-, moderate-, and high-mechanical-load-intensity and used with 59 possible accelerometer variables to predict mechanical load. Models were fit using the randomForest package in R. Model performance (coefficient of determination [R2] and median absolute error) was evaluated using cross-validation. RESULTS: The percentage of variation mechanical load intensity explained by the models ranged from 0.27 to 0.78 with median absolute errors ranging from 0.20 to 0.49. The model with R2 = 0.78 contained the known activity categories and the accelerometer variables, but this is not realistic for free-living situations where activity categories will not be known. The two free-living models with the highest R2 values included derived activity categories and accelerometer variables, and estimated, on average, 21.1 and 20.7 hours per day in low-intensity, 1.6 and 1.7 hours per day in moderate-intensity, and 0.0 and 0.5 hours per day in high-intensity osteogenic activity, respectively. CONCLUSION: It is assumed that higher intensity activities (i.e., jumping vs. jogging) result in higher GRF values, but depending on the actual execution of the movement, this is not always the case. This research demonstrated that models containing the accelerometer variables performed better in predicting GRF than those containing only the derived activity categories. This supports the hypothesis that accelerometers provide valuable objective information when evaluating mechanical loading on bone.

A better understanding of the association of the environment to young children's physical activity is needed to design effective behavioral interventions and to improve communities' infrastructures in ways that support the development of healthy behaviors. This thesis used data from the Iowa Bone Development Study (IBDS) to examine activity behaviors of young children in urban and rural Iowa. Mean daily minutes of moderate through vigorous physical activity (MVPA) and vigorous physical activity (VPA), as recorded by accelerometry-based physical activity monitoring in the IBDS, were compared by level of socioeconomic status (SES) and census block type (urban or rural). Media use (television and videogames), in hours per day by parental report, was similarly compared. Logistic regression was used to assess the association of census block type (urban or rural) with lower categories of MVPA and VPA, and with a high category of media use (exceeding the American Academy of Pediatrics (AAP) recommendation for ≤ 2 hours/day of media). Mean age of the 400 participants included in this thesis was 5.65 years (SD = 0.53), females comprised 53.5%. Children's mean daily minutes of MVPA and VPA were not significantly different among SES levels nor between urban and rural census blocks. Rural children had decreased odds for lower categories of MVPA (Boys' OR 0.91; 95% CI: 0.51, 1.60) (Girls' OR 0.89; 95% CI: 0.53, 1.50) and VPA (Boys' OR 0.84; 95% CI: 0.48, 1.48) (Girls' OR 0.90; 95% CI: 0.54, 1.52), but not significantly so. Lower SES boys and girls engaged in more daily media use (hours/day) than higher SES children, and a higher proportion of low SES children exceeded the AAP recommendation than did middle-level or high SES children. Rural boys' media use (2.7 hours/day) was higher than that of urban boys (2.3 hours/day) (95% CI: 0.06, 0.80 hours/day), whereas urban and rural girls' media hours/day were not significantly different. Odds for excess media use were higher for rural boys (OR 2.11; 95% CI: 1.14, 3.11) and for low SES boys (OR 2.99; 95% CI: 1.34 6.68), as well as for low SES girls (OR 4.12; 95% CI: 1.95, 8.71). Although rural and urban children's MVPA and VPA did not differ in this thesis, rural and low SES boys had both higher daily media hours and increased odds for exceeding AAP media recommendations. Odds for excess media also were increased for low SES girls. Interventions to improve healthy behaviors of young children by limiting screen-based recreation and/or supplying means for alternate activity and play opportunities may be especially beneficial when focused on lower SES and rural areas.

The purpose of this study was to develop a theory grounded in the health experiences of rural adolescents. By exploring the embodied experiences within a unique population of rural Iowan adolescents, many who are overweight/obese and/or of Hispanic descent, the developed theory was also used to inform a tailored health intervention for middle school students. The review of the literature revealed that the study of adolescent physical activity and body image concerns is largely measurement driven, and often explored from a deficit perspective. Thus, there remains a gap in the literature regarding the contextualized experience of health. This project used a qualitative approach to generate a theory grounded in stories adolescents shared regarding their health. Eighteen adolescents (13-15 years old) participated in one-on-one interviews. Grounded theory principles were used to understand how personal health experiences were socially constructed and explored the meanings participants derived from such experiences. An unstructured interview guide was used to gather information on health, physical activity, nutrition, and body image. The interviews were transcribed verbatim and analyzed using Charmaz's (2006) version of grounded theory. A total of 28 codes emerged from the data to construct the Theory of Embodied Health and Wellness. The complex interplay of personal health behaviors, eco-sociocultural influence, and everyday experience mold adolescents' embodied health and wellness experiences. Participants reported a wide range of personal, social, cultural and environmental influences on their health experiences. Feeling in control, connected, and competent were major themes in how participants experienced, maintained, or challenged their health experiences within their sociocultural environment. In addition to constructing the Theory of Embodied Health and Wellness, this project engaged adolescents in conversations related to their own health experiences to develop a sociocultural tailored health intervention. This project provides a practical example of how the target population of an intervention can be included during the formative research phase to ensure the intervention is tailored to meet their needs and interests.

This study evaluated a physical activity-based residential treatment program. It explored the current literature on adolescent treatment implementing physical exercise with parental participation, specifically at residential treatment centers. While the current literature strongly supports physical exercise and family involvement in adolescent treatment, research on combining physical exercise with family involvement is insufficient at best. The data were obtained from Telos Residential Treatment Center, an all-boys treatment program that incorporates a triathlon into their treatment curriculum and keeps pre- and posttest scores of the Youth Outcome Questionnaire for their students as well as completed questionnaires from students' parents. Research questions addressed whether or not the pre- and posttest scores support Telos' treatment program in terms of standardized test scores as well as possible differences in outcomes based on parent participation in the triathlon. Missing data and data corruption were major flaws in the study, significantly limiting the sample size. Consequently, the research questions could not be tested appropriately; however, there were statistically significant relationships (p < .05) between pre and post scores of intrapersonal distress as well as scores from the Global Assessment of Functioning, with both scores indicating change in a positive direction. Cohen's d also showed change in the desired direction in regards to interpersonal relationships and somatic symptoms. Students of parents who did not participate in a triathlon showed more improvement in interpersonal relationships as well as in intrapersonal distress and somatic symptoms. Parents who trained and physically participated in at least a portion of the triathlon with their son attributed their sons' treatment gains to the emotional intensity of the triathlon more than nonparticipating parents. Contrary to expectation, however, they did not weigh their own participation in the triathlon as heavily as nonparticipating parents in explaining treatment gains, specifically in improvements in how they and their son perceive and experience each other.

Increased risk for chronic disease is closely associated with individual nutrition, tobacco use, and physical inactivity. This thesis focuses on physical activity as a means of preventing select chronic diseases. A major barrier preventing engagement in physical activity is the built environment. Populations residing in rural environment are not afforded the abundance of opportunities for physical activity prevalent in most urban networks. Of the demographic living in rural environments, individuals with disability face additional barriers to physical activity than those without disability. This leads to a higher prevalence of chronic diseases associated with sedentary lifestyles among populations with disability. Few studies address the correlation between physical activity, chronic disease, and the built environment as they relate to individuals with disability. This thesis utilized independent samples t tests to evaluate variation among physical activity levels and the prevalence of chronic disease. In the first paper, four research objectives defined the parameters for comparison: (1) physical activity for individuals with disability in rural versus urban environments; (2) physical activity in rural environments for individuals with and without disability; (3) prevalence of chronic disease for individuals with disability in rural versus urban areas; and (4) prevalence of chronic disease in rural environments for individuals with and without disability. The four research objectives of the second paper are: (1) rural and urban physical activity comparison for the highest disability classification; (2) rural and urban physical activity comparison for individuals with disability using equipment; (3) rural and urban physical activity comparison for individuals with disability resulting from physical, mental, or emotional impairments; and (4) rural and urban physical activity comparison for individuals not reporting disability. The 2011 Behavioral Risk Factor Surveillance System (BRFSS) provided the data used to evaluate the correlation between these variables. The results of both studies indicate important statistical significance relating the rural built environment to lower levels of physical activity for individuals with disability. The varied statistical significance and small effect sizes, however, were contrary to the hypothesis and warrants further exploration of the complex relationship regarding the built environment, physical activity, and chronic disease.

Physical activity is known to offer health benefits. Additionally, research has linked religious involvement with health. Psychophysiological reactivity has links to coronary heart disease. This study examines the relationship between physical activity and religiosity in light of psychophysiological reactivity. The sample included 75 subjects, with a mean age of 71. 7 (SD = 6.11 ), with no history of cardiac incident. Religiosity was measured with the Religious Orientation Scale (ROS). Physical activity was assessed utilizing the Typical Week Physical Activity Scale. Psychophysiological reactivity was measured by blood pressure, heart rate, and self-report anger ratings in response to interpersonal challenge. Regression predicting reactivity, including ROS, total metabolic equivalence (MET) minutes, and interaction of the two resulted in significant prediction of systolic blood pressure change, F (3, 74) = 3.33, p = .024. Analyses suggest relationships between reactivity and religiosity are not mediated by physical activity. Indicating ROS may operate more influentially over prohibited than proactive behaviors.

Physical inactivity is a significant issue in the United States that has been linked to multiple health concerns. Few studies have used behavioral interventions during opportunities available in school, such as recess. There is a need for low effort and accessible interventions to increase children’s physical activity during these opportunities. The purpose of the current study was to evaluate the efficacy of a peer-implemented recess intervention that uses student pairing and feedback to increase physical activity. Step count was recorded by a pedometer. Peer leaders were trained in a group using behavioral skills training. A new leader performed the task-analyzed duties each week of intervention. An ABAB reversal design was used to evaluate the efficacy of the intervention. The results were mixed across the participants, but generally this study did not achieve experimental control in an ABAB design.

Adults with intellectual disabilities (ID) are at risk for negative health conditions due to high levels of sedentary behavior. Walking and cycling are the most common forms of physical activity engaged in by adults with ID. Research is limited in evaluating physical activity interventions for this population. The purpose of this study will be to evaluate the effectiveness of a token reinforcement intervention to increase distance walked for adults with mild to moderate ID at adult day training centers.

Rationale Within Australia, cardiac rehabilitation attendance is poor, with typically thirty percent of eligible patients attending programs. The majority of cardiac patients are not receiving the support or detailed information required to increase physical activity participation after hospitalisation. Further, many cardiac patients are not exercising independently, regardless of their attendance at cardiac rehabilitation. As physical activity is important in the prevention and treatment of heart disease, there could be substantial benefits to the individual and cost savings for the health system if cardiac patients were more active. Physical activity interventions based on social cognitive theory have demonstrated success in improving physical activity among people with chronic diseases. However, there is little research conducted with cardiac patients, in particular, with those who do not attend cardiac rehabilitation. This research addresses this gap in public health practice by providing an intervention to cardiac patients, irrespective of their attendance at cardiac rehabilitation, thereby addressing a population that is often overlooked and hard to reach. Research aims ?? To determine the uptake rate of cardiac rehabilitation in the north Illawarra and Shoalhaven areas of New South Wales and identify the characteristics of cardiac rehabilitation attendees and non attendees. ?? To evaluate the efficacy of a pedometer based physical activity intervention in cardiac patients referred to cardiac rehabilitation. Methodology This thesis consisted of three related studies: a cross sectional analysis of the characteristics of cardiac rehabilitation referrals (n = 944) over a 10 month period; and two randomised controlled trials conducted simultaneously. The Cardiac Rehabilitation Trial participants (n = 110) were patients who had attended cardiac rehabilitation; Community Trial participants (n = 215) were those who did not attend cardiac rehabilitation. The six week intervention evaluated in the trials included self monitoring of daily physical activity using a pedometer and step calendar, and two behavioural counselling and goal setting sessions delivered via telephone. Additional support for intervention group participants was provided through two brief telephone calls made after the six week intervention period. Self reported physical activity levels were collected at baseline, six weeks and six months. The questionnaire also collected information about psychosocial factors affecting physical activity participation. The exercise capacity of the participants in the Cardiac Rehabilitation Trial was objectively measured at baseline, six weeks and six months using a gas exchange analysis system. Results The cardiac rehabilitation uptake rate was 28.8 per cent of referred patients. Cardiac rehabilitation attendees were significantly younger and more likely to have had a coronary artery bypass graft surgery (CABGS) or percutaneous coronary intervention (PCI) procedure than non attendees. Study groups in both trials were not significantly different at baseline. In the Cardiac Rehabilitation Trial, improvements in total weekly physical activity sessions (p=0.002), walking time (p=0.013) and walking sessions (p<0.001) in the intervention group were significantly greater than the change in the control group at the end of the six week intervention. At six months, improvements in the intervention group remained significantly greater than the control group in total physical activity time (p=0.044), total physical activity sessions (p=0.016) and walking sessions (p=0.035) after adjusting for baseline differences. These self reported behavioural changes were corroborated by improvements in cardiorespiratory fitness at six months in the intervention group (p=0.010). Improvements in the intervention group in behavioural (p=0.039) and cognitive (p=0.024) self management strategy use were significantly greater than the controls at six weeks after adjusting for baseline differences. The improvement in cognitive strategy use (p=0.001) remained significantly greater in the intervention group compared to controls at six months after adjusting for baseline differences. Self efficacy, outcome expectancies and psychological distress were not significantly different between groups at six weeks or six months after adjusting for baseline differences. In the Community Trial, improvements in total weekly physical activity time (p=0.027), total physical activity sessions (p=0.003), walking time (p=0.013) and walking sessions (p=0.002) in the intervention group were significantly greater than the control group at six weeks after adjusting for baseline differences. At six months, improvements in total physical activity time (p=0.015), total physical activity sessions (p=0.019), walking time (p=0.002) and walking sessions (p=0.026) in the intervention group remained significantly greater than the control group after adjusting for baseline differences. Improvements in outcome expectancies (p=0.038) and cognitive self management strategy use (p=0.028) in the intervention group were significantly greater than the change in the control group at six weeks, after adjusting for baseline differences. However, these differences did not remain significant at six months. Conclusion This research showed that participation in a six week pedometer based intervention significantly increased the physical activity level and psychosocial status of people with heart disease. These findings suggest the pedometer based intervention could be offered as an effective and accessible option for those who do not attend cardiac rehabilitation to increase their physical activity levels. This intervention could also be promoted as an important adjunct to existing cardiac rehabilitation programs to promote adherence to physical activity after cardiac rehabilitation attendance. These studies provide community based evidence of an effective physical activity intervention for those eligible for cardiac rehabilitation, including those who do not attend. This provides a public health approach to cardiac rehabilitation programs and has the potential to improve health outcomes in this population.