Background: Injury and obesity are two of the leading public health problems in youth around the world. To reduce the burden of obesity, efforts are underway to increase physical activity participation; however, physical activity is also the leading cause of injury in youth. Recovery from injury is also important as long periods away from regular activity can have major effects on the health of youth. Objectives: This thesis is in manuscript format. The objective of the first manuscript was to determine whether relationships between physical activity and physical activity injuries are modified by BMI status in Canadian youth. The objective of the second manuscript was to examine the effect of BMI status on the time to recovery within youth who have suffered an injury. Methods: Data were obtained from the 2006 and 2002 Canadian Health Behaviour in School-Aged Children (HBSC) surveys. The 2006 Canadian HBSC was a nationally representative survey of 9672 youth in grades 6 through 10 from across Canada. The 2002 Canadian HBSC was an analogous survey of 7235 youth, of which approximately 50% experienced a medically treated injury. Analyses were driven by theory, and considered relationships among the major variables. Results: In manuscript 1, cross-sectional analyses indicated that those who reported high levels of physical activity experienced greater risks for physical activity injury in comparison to those with low levels of activity. BMI status was not identified as an effect modifier in any analyses. In manuscript 2, recovery for youth who were obese and suffered a combined injury (broken bone and strain/sprain) were longer than recovery times for normal weight youth. Times to recovery for obese youth were not significantly elevated for broken bones and sprain/strains. Conclusions: Physical activity participation relates to injury experiences in a consistent manner across BMI groups. Special safety precautions are not justified for obese youth in physical activity programs. BMI status was found to influence times for injury recovery. These are important clinical results that demonstrate that obesity may have a role in the osteoarticular health of youth and should be considered as a factor in treatment plans. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2009-08-26 10:59:39.956

The metabolic syndrome is characterized by obesity, insulin resistance, hypertension and dyslipidemia. It has also been suggested that hepatic steatosis and inflammation should be added to the classical components of the metabolic syndrome. Previous research on obesity and insulin resistance has examined the effects of many different fats and oils, however, the effects of canola oil on metabolic syndrome parameters have yet to be investigated. It is hypothesized that in a diet induced obese (DIO) rodent model, the combination of canola and flax oils will reduce the severity of metabolic syndrome parameters and favorably alter hepatic phospholipid (PL) and triacylglycerol fatty acid composition. The objective of the study was to investigate the biological effects of a 12 week dietary intervention with high fat diets based on various vegetable oils (high oleic canola, canola, canola/flax (3:1; C/F), safflower and soybean) and lard in 6 week old obese prone rats with regards to obesity, insulin resistance, lipidemia, hypertension, inflammation, hepatic steatosis, hepatic fatty acid composition and markers of hepatic fatty acid oxidation and synthesis. Overall the C/F diet attenuated more of the components of the metabolic syndrome, including obesity, glycemia, lipidemia, inflammation and hepatic steatosis, than the other high fat diets in DIO rats. However, each of the dietary treatments attenuated various components of the metabolic syndrome suggesting that all dietary fats and oils have their role in the prevention of different components of the metabolic syndrome. Additionally, the C/F diet led to increased eicosapentaenoic acid and docosahexaenoic acid concentrations in hepatic PL suggesting that α-linolenic acid can be efficiently converted to its very long chain derivatives in DIO rats. Thus, the addition of flax oil to conventional canola oil, in the C/F diet, appeared to enhance the beneficial effects of canola oil on metabolic syndrome parameters.

No description available.

The metabolic syndrome is characterized by obesity, insulin resistance, hypertension and dyslipidemia. It has also been suggested that hepatic steatosis and inflammation should be added to the classical components of the metabolic syndrome. Previous research on obesity and insulin resistance has examined the effects of many different fats and oils, however, the effects of canola oil on metabolic syndrome parameters have yet to be investigated. It is hypothesized that in a diet induced obese (DIO) rodent model, the combination of canola and flax oils will reduce the severity of metabolic syndrome parameters and favorably alter hepatic phospholipid (PL) and triacylglycerol fatty acid composition. The objective of the study was to investigate the biological effects of a 12 week dietary intervention with high fat diets based on various vegetable oils (high oleic canola, canola, canola/flax (3:1; C/F), safflower and soybean) and lard in 6 week old obese prone rats with regards to obesity, insulin resistance, lipidemia, hypertension, inflammation, hepatic steatosis, hepatic fatty acid composition and markers of hepatic fatty acid oxidation and synthesis. Overall the C/F diet attenuated more of the components of the metabolic syndrome, including obesity, glycemia, lipidemia, inflammation and hepatic steatosis, than the other high fat diets in DIO rats. However, each of the dietary treatments attenuated various components of the metabolic syndrome suggesting that all dietary fats and oils have their role in the prevention of different components of the metabolic syndrome. Additionally, the C/F diet led to increased eicosapentaenoic acid and docosahexaenoic acid concentrations in hepatic PL suggesting that α-linolenic acid can be efficiently converted to its very long chain derivatives in DIO rats. Thus, the addition of flax oil to conventional canola oil, in the C/F diet, appeared to enhance the beneficial effects of canola oil on metabolic syndrome parameters.

Obesity has long been recognised as a risk factor for the development of variety of life threatening diseases; examples include diabetes mellitus and cardio vascular disease. In particular, in young women, it is widely thought to predispose towards impaired glucose tolerance and gestational diabetes. Obesity is not only common but it is increasing in prevalence despite the efforts made by individuals and their health advisors to avoid it. Identification of factors contributing to obesity could be useful in planning preventative policies. Many women relate the onset of their obesity to one or more of their pregnancies. We now know that there is more to obesity than the actual amount of excess weight. The adverse metabolic effects of obesity are proved to be greater when excess fat deposition is central rather than peripheral. The idea that fat deposition may be directed to different body sites with different effects on glucose tolerance and insulin levels, is a relatively new concept. The majority of investigators have focused only on the magnitude of weight changes during pregnancy and postpartum. There is not much information with regard to the compartmental changes in body composition during and after delivery. Most studies in the developed world show maternal net fat gain accompanying pregnancy. The extent to which such fat gain is physiological, and what is its beneficial effects is unknown. It is therefore important to study the impact of other factors with possible effects on fetal growth and maternal body composition. The present work examines further the question of fat storage by means of a longitudinal study to establish changes in body fat content during normal pregnancy and postpartum and also its relationship to maternal glucose tolerance, fetal metabolism, new-born anthropometry and infant growth. For this purpose, 123 women were recruited at their first visit to Antenatal Clinics of the Northern General Hospital, from which 73 completed 3 visits during pregnancy and 46 participated in the whole course of the study. Maternal anthropometry and body composition were measured at 13 (5 - 15), 24 (23 - 32) and 36 (34 - 41) weeks gestation during pregnancy and also 6 weeks and 6 months postpartum. Skinfold thickness measurements and Bio-electrical Impedance were used to assess the changes in body composition during pregnancy and postpartum. Glucose tolerance tests were performed at 28-31 weeks gestation. Insulin and/or C- peptide levels were also collected at birth and assessed later. Infant anthropometry (weight, length and head circumference) were measured at birth, 6 weeks and 6 months postpartum. The subjects were divided into four groups of under-weight, normal weight, over- weight and obese, based on their early pregnancy BMI. The statistical analyses were performed on the whole group and also the groups were then compared for the above mentioned variables. The two methods (Skinfold thickness measurements and Bio-electrical Impedance) showed a reasonable agreement in predicting the fat changes during pregnancy. A considerable variation was observed, however, between the two methods in the results of changes from early pregnancy to postpartum. Therefore, direct interpretation of skinfold thickness (which was consistent with the converted version of it to fat mass) was alone chosen to derive the conclusions During pregnancy, a formula which is corrected for hydration changes during gestation, was used to convert skinfold thicknesses to fat mass. The results confirmed that a substantial net gain of fat was made during pregnancy of which a significant amount was still retained at 6 month postpartum. Maternal weight increased (10.87 kg ± 4.67), but it reverted to the early pregnancy values by 6 months postpartum. The rate of fat and weight changes was significantly higher in the first half of pregnancy compared to later. The observed changes in maternal weight and fat mass, during pregnancy were not significantly different between the BMI groups (normal weight, over-weight and obese group). At the postpartum period, the obese group retained more of the net fat gain than the other two groups. A state of redistribution of fat tissue was observed in the subjects in particular in the obese group who had a tendency towards central fat retention. Gestational fat gain was not directly related to infant birth weight. In this well nourished population, maternal early pregnancy lean body mass (LBM) was the most significant predictor of infant birth weight. There was a positive correlation between maternal BMI and cord insulin (r=0.44, p=0.002) and/or C-peptide (r=0.33, p=0.008). In addition higher levels of insulin were observed in large for gestational age (LGA) babies in comparison with the average for gestational age (AGA) babies. These observations might have an important impact on the care of overweight women. It may be that reduction of maternal BMI in the prepregnancy period in the obese women would reduce the risk of gestational diabetes and also the rate of fetal hyperinsulinemia and macrosomia. Further investigation on this hypothesis is needed. In summary; obese women had significantly heavier babies than the normal weight women. Maternal fasting glucose was significantly correlated to infant birth weight. On the other hand, maternal fasting glucose and the level of fetal insulinisation was significantly associated with maternal early pregnancy BMI. This is likely to be a metabolic effect operating throughout gestation. What we can suggest is that , in the studies of maternal glucose metabolism and fetal growth, the confounding effects of maternal BMI should be seriously considered

Thesis (M.S.) -- Central Connecticut State University, 2007. / Thesis advisor: Ruth Rollin. "... in partial fulfillment of the requirements for the degree of Master of Science in Biological Sciences." Includes bibliographical references (leaves 68-73). Also available via the World Wide Web.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains v, 58 p. Includes abstract. Includes bibliographical references (p. 43-48).

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.S.N.)--State University of New York at Binghamton, Decker School of Nursing, 2006. / Includes bibliographical references.

Thesis (Ph.D.)--George Mason University, 2008. / Vita: p. 130. Thesis director: Ancha Baranova. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biosciences. Title from PDF t.p. (viewed July 18, 2008). Includes bibliographical references (p. 113-129). Also issued in print.