Objectives: To determine whether for a given waist circumference (WC), a larger hip circumference (HC) was associated with a reduced risk of insulin resistance, type 2 diabetes (T2D), hypertension and cardiovascular disease (CVD) in HIV-infected patients. A second objective was to determine whether, for a given WC, the addition of HC improved upon estimates of abdominal adiposity, in particular visceral adipose tissue (VAT), compared to those obtained by WC alone. Methods: HIV-infected men (N=1481) and women (N=841) were recruited between 2005 and 2009. WC and HC were obtained using standard techniques and abdominal adiposity was measured using computed tomography. Results: After control for WC and covariates, HC was associated with a lower risk of HOMA-IR (p<0.05) and T2D [Men: OR=0.91 (95% CI: 0.86-0.96); Women: OR=0.91 (95% CI: 0.84-0.98)]. For a given WC, HC was also associated with a lower risk of hypertension (p<0.05) and CVD [OR=0.94 (95% CI: 0.88-0.99)] in men, but not women. Although HC was negatively associated with VAT in men and women after control for WC (p<0.05), the addition of HC did not substantially improve upon the prediction of VAT compared to WC alone. Conclusions: The identification of high-risk HIV-infected individuals by WC alone is substantially improved by the addition of HC. Estimates of VAT by WC are not substantially improved by the addition of HC and thus variation in visceral adiposity may not be the conduit by which HC identifies increased health risk. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2012-09-04 16:27:16.249

Head circumference and leg length are two important markers for disease outcomes in later life. It has been reported that head circumference values in childhood may be closely related to the brain development and future intellectual functioning. Short leg length in childhood is suggested to have association with an increasing risk of coronary heart disease, diabetes and cancer. Given the potential childhood length and adult disease linkage, it is important to identify the determinants of childhood head circumference and leg length. Breastfeeding is suggested to be a potential postnatal factor that affects head circumference and leg length. However, some studies examining impacts of breastfeeding on leg length and head circumference in childhood reported inconsistent or null findings, indicating that the association between breastfeeding, head circumference and leg length remains controversial. Here we reviewed several studies that investigated the relationship between breastfeeding, head circumference and leg length, and in some but not all studies there was controlling for the effects of other potential early life influences, including parental height, prenatal factors and other postnatal factors on head circumference and leg length. Collectively, the illustrations on these relationships would be useful in investigating the leg length/head circumferencelater disease outcomes associations. / text

Objectives: The waist-to-stature ratio (WSR) is newly developed index, proposed to be of greater value as a simple anthropometric indicator, for predicting abdominal obesity and related cardiovascular co-morbidities in adults and children. This study examined age and gender differences in waist-to-stature (WSR) as measure of centripetal fat patterning in a sample of children in Pretoria, South Africa.

Objectives: The aim of this study was to determine the prevalence of MetS among different African populations using the new Joint Statement Criteria. Hereafter we aimed to determine whether waist or neck circumference is the best predictor of MetS risk after ethnic, gender and age-specific cut-points were developed. Lastly, we aimed to determine whether afore-mentioned cut-point can predict albumin:creatinine ratio as a marker of target organ damage. Methods: The study sample (N=409) comprised of urban African (men, N=101; women, N=99) and Caucasian (men, N=101; women, N=108) teachers from the Dr. Kenneth Kaunda Education district in the North-West Province, South Africa. Participants were aged between 25 and 65 years. Anthropometric measurements, albumin:creatinine ratio and other markers of the metabolic syndrome (MetS) (systolic and diastolic blood pressure [SBP and DBP], glucose, triglycerides [TG] and high density lipoprotein [HDL]) were determined. Results: Africans (65 and 63 % for men and women) and Caucasian men (73%) showed high prevalence of MetS; ROC analysis determined neck circumference (NC) cut-points of 39 and 35 cm for young and older African men, 32 and 35 cm for young and older African women, 40 and 41 cm for Caucasian men and 34 and 33 cm for Caucasian women. This NC cut-point can be used to determine metabolic syndrome risk in all groups, except in African women; ROC developed waist circumference (WC) cut-points were 91 cm for all African male groups, 84, 81 and 84 cm for young, older and total group of African women. Suggested WC cut-points for Caucasian men were 93 cm for the young group and 97 cm for older as well as total Caucasian male groups, while cut-points for Caucasian women were 87 cm, 79 cm and 84 cm for young, older and total Caucasian women. These WC cut-points were good measures of metabolic syndrome risk in all groups; neither cut-point of WC nor NC could increase the risk of albumin:creatinine ratio. Conclusion: African women as a group present with few MetS risk factors and glucose is associated with renal function risk in Africans; NC cut-points may be used as an additional anthropometric marker to predict the metabolic syndrome in a South African cohort, but not in African women; WC cutpoints demonstrated to be good predictors of the metabolic syndrome in the same South African cohort, especially among men; WC would seem to be the best measure of MetS risk in all African populations, although NC can also be used for this purpose in all African populations, except in African women. / Thesis (PhD (Human Movement Science))--North-West University, Potchefstroom Campus, 2012

Objectives: The aim of this study was to determine the prevalence of MetS among different African populations using the new Joint Statement Criteria. Hereafter we aimed to determine whether waist or neck circumference is the best predictor of MetS risk after ethnic, gender and age-specific cut-points were developed. Lastly, we aimed to determine whether afore-mentioned cut-point can predict albumin:creatinine ratio as a marker of target organ damage. Methods: The study sample (N=409) comprised of urban African (men, N=101; women, N=99) and Caucasian (men, N=101; women, N=108) teachers from the Dr. Kenneth Kaunda Education district in the North-West Province, South Africa. Participants were aged between 25 and 65 years. Anthropometric measurements, albumin:creatinine ratio and other markers of the metabolic syndrome (MetS) (systolic and diastolic blood pressure [SBP and DBP], glucose, triglycerides [TG] and high density lipoprotein [HDL]) were determined. Results: Africans (65 and 63 % for men and women) and Caucasian men (73%) showed high prevalence of MetS; ROC analysis determined neck circumference (NC) cut-points of 39 and 35 cm for young and older African men, 32 and 35 cm for young and older African women, 40 and 41 cm for Caucasian men and 34 and 33 cm for Caucasian women. This NC cut-point can be used to determine metabolic syndrome risk in all groups, except in African women; ROC developed waist circumference (WC) cut-points were 91 cm for all African male groups, 84, 81 and 84 cm for young, older and total group of African women. Suggested WC cut-points for Caucasian men were 93 cm for the young group and 97 cm for older as well as total Caucasian male groups, while cut-points for Caucasian women were 87 cm, 79 cm and 84 cm for young, older and total Caucasian women. These WC cut-points were good measures of metabolic syndrome risk in all groups; neither cut-point of WC nor NC could increase the risk of albumin:creatinine ratio. Conclusion: African women as a group present with few MetS risk factors and glucose is associated with renal function risk in Africans; NC cut-points may be used as an additional anthropometric marker to predict the metabolic syndrome in a South African cohort, but not in African women; WC cutpoints demonstrated to be good predictors of the metabolic syndrome in the same South African cohort, especially among men; WC would seem to be the best measure of MetS risk in all African populations, although NC can also be used for this purpose in all African populations, except in African women. / Thesis (PhD (Human Movement Science))--North-West University, Potchefstroom Campus, 2012

Objective: Pedometer programs are effective in increasing physical activity in sedentary individuals, a population that is at an increased for developing metabolic syndrome and each of its individual components. The aim of this study was to observe the effects of incremental increases in pedometer assessed physical activity on MetS components in sedentary overweight women. Design: This study was a longitudinal, quasi-experimental design. Participants were recruited from a 12-week work-site pedometer program and grouped after the intervention based on their self-paced increases in pedometer assessed physical activity with (a) active participants that increased their daily activity by mean volume >3000 steps/day or (b) participants who remained sedentary. Subjects: A multi-ethnic heterogeneous sample of seventy-seven sedentary middle-aged women (BMI: 30.15 plus or minus 5.24 kg/m2, age: 46.00 plus or minus 9.93 years). Measurements: Self-reported physical activity, pedometer assessed physical activity (steps/day), body mass index, resting heart rate, waist circumference, blood pressure, triglycerides, HDL-C and fasting glucose at baseline and after the 12-week program. Results: The active group showed significant within-group improvements (P less than or equal to .01) in waist circumference and fasting glucose. Significant between group changes were observed in resting heart rate (P less than or equal to .01), weight (P less than or equal to .01), BMI (P less than or equal to .01), and systolic blood pressure (P less than or equal to .001); however, the changes observed in systolic blood pressure were not independent of weight loss. Conclusions: Our study showed that incremental increases in steps/day over 12 weeks is effective in inducing mild, but favorable changes in some MetS components. This data suggests that this approach to increasing step/day is a viable starting point for sedentary individuals that may find it difficult to initially accumulate 10,000 steps/day.

A series of experiments was conducted to evaluate the effects of nutrition during calfhood (defined as the period from 10 to 26-30 wk of age) and peripubertal period (defined as the period from 27-31 to 70-74 wk of age) on sexual development and reproductive function in beef bulls. The overall objective of these experiments was to evaluate the effects of nutrition on endogenous metabolic hormones (leptin, insulin, GH, and IGF-I), gonadotropins and testosterone concentrations, sexual development, sperm production, and semen quality in bulls. The results of these experiments demonstrated that nutrition affected GnRH secretion and sexual development in bulls. Increased nutrition during calfhood resulted in a more sustained increase in LH pulse frequency during the early gonadotropin rise and greater testicular development at maturity. On the other hand, low nutrition during calfhood suppressed LH secretion during the early gonadotropin rise and resulted in delayed puberty and reduced testicular development at maturity. When low nutrition was accomplished by restricted feed intake, hypothalamic and pituitary function were compromised and LH secretion was more severely affected. Temporal associations between LH secretion patterns and circulating IGF-I concentrations implied that IGF-I is a possible signal to the central metabolic sensor involved in translating body nutritional status to the GnRH pulse generator. Nutrition also affected testicular steroidogenesis (testosterone concentrations), indicating effects on the number or function of Leydig cells, or both. Age-related increases in physiological and GnRH-stimulated circulating testosterone concentrations were hastened in bulls receiving high nutrition and delayed in bulls receiving low nutrition; these effects were probably mediated by both LH secretion and IGF-I concentrations. Circulating leptin and insulin may have only permissive roles on GnRH secretion, but may enhance testicular development. Growth hormone concentrations decreased concomitantly with increasing IGF-I concentrations during sexual development in bulls, suggesting that the testes could contribute considerable amounts of circulating IGF-I. In conclusion, management strategies to optimize reproductive function in bulls should focus on increasing nutrition during calfhood.

A series of experiments was conducted to evaluate the effects of nutrition during calfhood (defined as the period from 10 to 26-30 wk of age) and peripubertal period (defined as the period from 27-31 to 70-74 wk of age) on sexual development and reproductive function in beef bulls. The overall objective of these experiments was to evaluate the effects of nutrition on endogenous metabolic hormones (leptin, insulin, GH, and IGF-I), gonadotropins and testosterone concentrations, sexual development, sperm production, and semen quality in bulls. The results of these experiments demonstrated that nutrition affected GnRH secretion and sexual development in bulls. Increased nutrition during calfhood resulted in a more sustained increase in LH pulse frequency during the early gonadotropin rise and greater testicular development at maturity. On the other hand, low nutrition during calfhood suppressed LH secretion during the early gonadotropin rise and resulted in delayed puberty and reduced testicular development at maturity. When low nutrition was accomplished by restricted feed intake, hypothalamic and pituitary function were compromised and LH secretion was more severely affected. Temporal associations between LH secretion patterns and circulating IGF-I concentrations implied that IGF-I is a possible signal to the central metabolic sensor involved in translating body nutritional status to the GnRH pulse generator. Nutrition also affected testicular steroidogenesis (testosterone concentrations), indicating effects on the number or function of Leydig cells, or both. Age-related increases in physiological and GnRH-stimulated circulating testosterone concentrations were hastened in bulls receiving high nutrition and delayed in bulls receiving low nutrition; these effects were probably mediated by both LH secretion and IGF-I concentrations. Circulating leptin and insulin may have only permissive roles on GnRH secretion, but may enhance testicular development. Growth hormone concentrations decreased concomitantly with increasing IGF-I concentrations during sexual development in bulls, suggesting that the testes could contribute considerable amounts of circulating IGF-I. In conclusion, management strategies to optimize reproductive function in bulls should focus on increasing nutrition during calfhood.

Current health recommendations encourage weight loss for overweight and obese individuals. However, the importance of weight to health is still unclear. The purpose of this study was to determine the impact of weight loss on overall health in a sample of adults who have completed a 10 or 12 week weight loss intervention. The study sample included males and females (n =99) between the ages of 27 -64 years that had a BMI of 29-45 kg/m². The study design is a secondary data analysis of data from two different behavioral weight loss interventions. Both interventions prescribed a reduced calorie diet, increased physical activity, and self-monitoring of diet and physical activity. Of the 99 participants, 28 lost greater than 5% of baseline body weight and saw the most significant changes in waist circumference (p<0.001), systolic blood pressure (p=0.004), diastolic blood pressure (p=0.002), and total cholesterol (p=0.001). This group experienced improvements in every lab value tested. More research with larger sample sizes and longer trial periods need to be done in order to strengthen the validity of the weight loss interventions.

Approximately 32% of college-aged individuals are overweight or obese, yet few weight loss programs have effectively motivated this population to adopt a healthier lifestyle. A majority of this population frequently uses the social networking site Facebook. This study examined the impact of a Facebook social support group on weight loss efforts of college students. A total of 24 students were randomly assigned to either the intervention group, which consisted of a Facebook support group, or control group after attending a one-time weight loss class. Assessments were taken at baseline and four weeks. Of participants in this study, 83.3% were Facebook users. All but two participants were female with 47.8% identifying as black, non-Hispanic and 39.1% as white, non-Hispanic. Most participants were considered obese or overweight with 39-inch median waist circumference for women and 44-inch median waist circumference for men. The primary outcome was a mean weight loss of -3.55 ± 4.25 lbs. for those in the intervention group compared to -1.61 ± 3.24 lbs. for the control group after four weeks. Though results were not statistically significant, the intervention group lost more weight than the control group. Results indicate the potential for an innovative weight loss aid that utilizes an online site already integrated into the lifestyle of college students.