Background: In recent history, there have been significant increases in both soft drink consumption and the prevalence of obesity throughout the developed world. To help curb the obesity epidemic, a better understanding of the behaviors contributing to weight and fat gain is vital. Objective: To examine the extent to which soft drink consumption is predictive of changes in body composition in middle-aged women over a 4-year period, while statistically controlling for age, energy intake, physical activity, and menopause status. Design: A prospective cohort design over 48 months with no intervention. Self-reported soft drink consumption was used to predict changes in body weight and body fat percentage over the study period. Subjects included 170 healthy women (mean: 41.5 yrs at baseline). Soft drink consumption and menopause status were measured by questionnaire. Body weight was assessed using a calibrated, electronic scale, and total body fat percentage was measured using dual energy x-ray absorptiometry (DEXA). Energy intake was estimated using 7-day, weighed, food records. Results: Women who primarily consumed sugar-sweetened soft drinks gained significantly more weight than those who consumed diet soft drinks or no soft drinks (p = 0.022), even after controlling for confounding variables, except energy intake, which weakened the relationship by 28%. Changes in body fat were unrelated to the type of soft drink consumed. Women who consumed 7+ soft drinks per week gained significantly less body fat (p = 0.015) and body weight (p = 0.052) over the 4-year study compared to women who consumed fewer soft drinks per week. Further investigation revealed that women who consumed 7+ soft drinks per week did so almost exclusively in the form of diet soft drinks (87%). Conclusions: Drinking sugar-sweetened soft drinks significantly increases risk of weight gain compared to consuming diet soft drinks or no soft drinks over a 4-year period. It appears that this relationship is partly due to differences in energy intake among those who drink different types of soft drinks. Thus, it appears that consuming diet soft drinks or no soft drinks instead of sugar-sweetened soft drinks may be a worthwhile method of preventing weight gain.

Prolonged second stage of labor, excessive gestational weight gain and cesarean delivery has been associated with adverse maternal and fetal outcomes. Physical activity during pregnancy is a modifiable risk factor which has never been studied among Hispanic women. Gestational weight gain, another modifiable risk factor has only been evaluated as a risk factor for cesarean delivery in two studies among women induced for labor. To date, no study has examined the effect of duration of second stage of labor on intra-ventricular hemorrhage in very preterm births. We examined these maternal risk factors for prolonged second stage of labor, rate of cesarean delivery and fetal outcomes. The first study evaluated the association between physical activity and duration of second stage of labor. Prior studies regarding physical activity and duration of second stage of labor have been conflicting and none have examined the Hispanic population. During pregnancy, activities such as household chores, childcare, sports and women's occupation constitute a significant proportion of physical activity but have not been considered in prior studies. We examined the association between total physical activity (occupational, sport/exercise, household/care giving, and active living) during pre, early and mid-pregnancy and duration of second stage of labor in a prospective cohort of 1,231 Hispanic participants. Physical activity was quantified using the Kaiser Physical Activity Survey administered during pregnancy. Using multivariate linear regression we did not find statistically significant association between pre, early and mid-pregnancy physical activity and duration of second stage of labor. The second study focused on the effect of gestational weight gain on the cesarean delivery rate after induction of labor. The rate of induction of labor (IOL) has more than doubled from 9.5% in 1990 to 22.5% in 2006. Cesarean delivery usually follows a failed IOL and is associated with maternal and fetal morbidity. One of the two studies evaluating the effect of gestational weight gain on the rate of cesarean section in patients undergoing IOL was restricted to women with normal Body Mass Index (BMI) and the other was subjected to bias because more than half of the patients were missing BMI data. Therefore, we evaluated the effect of gestational weight gain on the rate of cesarean delivery after labor induction. In a retrospective cohort study design, using data from May 2005 to June 2008 and a multivariate logistic regression we found a 13% increase in risk of cesarean delivery with 5 kg increase in gestational weight gain. Finally, we evaluated the effect of mode of delivery and duration of second stage of labor on intra-ventricular hemorrhage (IVH) among early preterm births. IVH is a serious complication associated with preterm birth and important predictors of cerebral palsy and neurodevelopmental delays. Prior studies on this relationship in early preterm births are sparse. In a retrospective cohort study of newborns born less than 30 weeks or less than 1500 g between May 2003 and August 2008, we found an increase in risk of IVH after vaginal delivery. However, duration of second stage of labor had no significant effect on risk of IVH.

Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x = 14) or tetraploid (2n = 4x = 28). Transforming annual ryegrass from diploid to tetraploid often results in increased seedling vigor, more robust growth and, thus, supposedly greater yield. There has been conflicting research that suggests no difference in yield between diploid and tetraploid cultivars, but livestock producers’ question whether benefits exist to utilizing tetraploid cultivars for grazing cattle. This study sought to determine if annual ryegrass cytotype affected cattle average daily gain. Although there were no differences in average daily gain between cytotypes, there were differences among cultivars. In 2017, Jumbo (4x) produced the greatest weight gain, while in 2018, Tam-90 (2x) generated the greatest gain. This study suggests that there are no advantages attributed to average daily gain by utilizing tetraploid, as opposed to diploid cultivars.

Maternal weight during pregnancy has an important impact on multiple aspects of health for both mothers and their children. This dissertation investigated whether pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) independently impact a child’s health service utilization. Methods: This dissertation included four studies. The study population for the first three studies was all women who delivered a singleton, live infant in Ontario between 2012-2014 and have information contained in the Better Outcomes Registry and Network (BORN) Ontario registry. Health service data in the first 24 months following birth were collected via health administrative databases housed at ICES. I investigated whether there was an association of pre-pregnancy BMI (Chapter 2) or GWG (Chapter 3) with pediatric health service use. I then investigated whether adverse birth outcomes, specifically small for gestational age (SGA) or preterm birth (PTB), mediated this relationship (Chapter 4). Finally, I developed a cost effectiveness evaluation framework for the implementation of a maternal weight intervention program to limit the impact on the child (Chapter 5).Findings: Children born to women with pre-pregnancy obesity relative to normal weight experienced higher rates of hospitalization (adjusted incidence rate ratio [aIRR]: 1.20, 95% CI:1.17,1.24), physician visits (aIRR: 1.05, 95% CI: 1.04,1.05) and emergency department (ED)visits (aIRR: 1.27, 95% CI: 1.25,1.29). Children born to normal weight (aIRR: 1.07, 95% CI:1.05,1.09) or overweight (aIRR: 1.04, 95% CI: 1.01,1.07) mothers with above recommended (versus recommended) GWG had increased ED visits. Children born to underweight women with below recommended GWG had increased hospitalizations (aIRR: 1.31, 95% CI: 1.14,1.51) and physician visits (aIRR: 1.14, 95% CI: 1.10,1.17). PTB (56.74%), and SGA (6.83%)iv mediated the relationship of below recommended GWG and pediatric hospitalizations only. Adetailed cost effectiveness framework is outlined to investigate an intervention plan targeting GWG to limit adverse pediatric health outcomes. Discussion: The findings of this dissertation indicate that below or above optimal maternal weight is associated with pediatric health service use. This dissertation serves as a call to action to better inform clinical practice and impact health service policy related to maternal weight via early intervention.

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Aging is characterized by a progressive stiffening of large elastic arteries in the cardiothoracic region. Importantly, large artery stiffness is an independent predictor of cardiovascular events and mortality in both healthy and diseased populations. The results of several studies suggest that obesity, particularly visceral adiposity, is associated with the accelerated stiffening of central elastic arteries in middle-aged and older adults. Despite the widely recognized association between obesity, aging and arterial stiffness, there remains a paucity of information regarding both the initiation of arterial stiffening and effective treatment strategies. To address these issues, we tested the hypotheses that weight gain increases arterial stiffness in nonobese young males, and atorvastatin treatment reduces large artery stiffness in overweight and obese middle-aged and older adults. Consistent with our first hypothesis, weight gain increased arterial stiffness in nonobese young men. In addition, we demonstrated that, independent of total body fat, those individuals with relatively larger increases in abdominal visceral fat also experienced correspondingly larger increases in arterial stiffness. Regarding our second hypothesis, atorvastatin treatment decreased arterial stiffness in overweight and obese middle-aged and older adults. Importantly, the reduction in arterial stiffness with atorvastatin appeared to be independent of the reduction in C-reactive protein. The findings of the present studies could potentially lead to the identification of effective strategies for the prevention and treatment of arterial stiffening in the population. / Ph. D.

College-age adults gain weight more rapidly than the general population, with a mean weight gain of ~1.8 to 4 kilograms during their first year at college. The purpose of this pilot RCT was to test the efficacy of a semester long internet weight-loss program based upon social cognitive theory for overweight college freshmen. Qualitative focus groups were used to provide feedback on content of the active intervention. Participants (n=27; mage=18.5±.6; mweight=90kg±18; 74% female) were randomly assigned to the active intervention (Fit Freshmen; FF) or a health information control group and completed baseline and 3 month follow-up measurements. When compared to controls FF participants experienced higher improvement in self-regulatory skills for portion control, fruit and vegetable consumption and physical activity (all p's<.05). Consumption of dietary fat and added sugar also decreased significantly for FF subjects when compared to controls (all p's<.05) while total energy intake differences were significant (p<.09). Trends in increased physical activity were present, but not significantly different between groups. Finally, FF lost significantly more weight than controls (mdifference=2.2kg; p<0.05) and more fat mass (mdifference=1kg; p<0.09). Themes for content improvement included providing a more detailed meal plan, reducing email contact, and increasing social activity opportunities. Program characteristics that were positively evaluated included the flexible exercise program, incentives for weight loss, and use of an onsite weigh station. This study provides promising outcomes for a scalable internet-based weight loss program for college freshmen and highlights features that could be improved to be more attractive to this population. / Master of Science

To determine the effect of estrogen on weight changes in women, eight adult females were followed for a period of six months subsequent to hysterectomy or ovariohysterectomy. Three groups comprised the study: 1) a hysterectomy or control group, 2) an ovariohysterectomy group with estrogen replacement therapy, and 3) an ovariohysterectomy without estrogen treatment group. Body weight, caloric intake, and activity level were recorded for the eight prospective subjects over the six month period. Weight data were gathered from past medical records on an additional 19 patients meeting the treatment criteria. Weight changes between groups were not statistically significant. A trend in weight changes among the groups was noted. The hysterectomy group lost five pounds, ovariohysterectomy treated group lost one pound and the untreated group, 0.2 pound. The same trend in weight changes was noted when data from prospective and retrospective subjects were combined. Caloric intake and activity levels did not explain all changes noted. Detailed information on subjects was presented as case studies. The results supported the concept that endogenous estrogen protects against weight gain; evidence did not support the comparable action of exogenous estrogen. Subjects having ovariohysterectomy stated that they experienced appetite changes such as cravings for sweets, undesirable muscle tone and body contour changes, and difficulty in ability to control weight. Further research with a larger sample size is needed to determine direct relationships between female hormones and suppression of weight gain in women. / Master of Science

The purpose of this study was to explore student athletes' weight-control behaviors. Data consisted of student athletes' responses to a modified version of the Michigan State Weight-Control Survey (Dummer, Rosen, Heusner, Roberts, & Counsilman, 1987). Specifically, the study was designed to explore the following research hypotheses: 1. There is no significant relationship between the weight-control behaviors of athletes competing in sports with weight restrictions (e.g., wrestling) and sports without weight restrictions (e.g., tennis). 2. There is no significant relationship between the weight-control behaviors of athletes competing in sports with subjective judging (e.g., diving) and sports with objective scoring (e.g., swimming). 3. There is no significant relationship between the weight-control behaviors of male athletes and female athletes. The sample was drawn from intact athletic teams at the university under study. All members of the selected teams were invited to participate. The results of this research contributed to both practice and research. Athletic department staff and coaches, student affairs practitioners, and health care practitioners were made more aware of weight-control issues for athletes and might design programs and services to address the issue. The study also lays the groundwork for future research. Scholars may wish to examine other elements of sport (e.g., level of competition, seasonal demands) and their effects on the weight-control behaviors of athletes. The results revealed that there is a significant relationship between weight-control behaviors and the type of weight restrictions (weight restricted versus non-weight restricted) a sport places on athletes (p < .05). There is also a significant relationship between the sex of athletes and the weight-control behavior that they engage in (P < .05). The relationship between the weight-control behaviors and the type of judging (subjective versus objective scoring) involved in the sport was also examined. Though the relationship was not significant at the p = .05 level, it was significant at the p = .1 level. The results of this research addressed an existing gap in the current body of knowledge. There is very little research about weight-control behaviors of athletes in specific groups of sports. Better understanding the demands that different types of sports place on athletes may enable future scholars and practitioners to better serve the population. / Master of Arts