Introduction: Osteoporotic fractures, a major public health problem in aging populations, can lead to increased disability and mortality. Though rheumatoid arthritis (RA) patients have a higher risk for fractures than healthy populations, it is not known how hip structural geometry and body composition, two factors associated with bone strength, affect fracture risk in this population. The overall goal of this dissertation is to examine the association between RA, fracture, hip structural geometry, and body composition, in the participants of the Women's Health Initiative (WHI).Methods: The association between probable RA and fracture risk was tested using the entire WHI cohort (n=161,808). The association between probable RA and hip structural geometry was tested, both cross-sectionally and longitudinally, in a smaller sample (n=11,020) of participants from the WHI Bone Density Centers (WHI-BMD). The last study, testing the association between probable RA and body composition was also conducted in the WHI-BMD cohort.Results: In comparison to the non-arthritic group, the probable RA group had a significant 50%, 2-fold, and 3-fold increase in any, spine, and hip fracture, respectively. The association was not mot modified by age or ethnicity, but glucocorticoid use altered the association between RA and spine fractures. In terms of geometry, the probable RA had a significantly lower (p<0.05) mean hip BMD, outer diameter, cross-sectional area, and section modulus at the narrow neck region compared to control groups, indicating reduced bone strength. Body composition changes were present between the probable RA and the control group, with the probable RA group having statistically lower estimate of lean mass and statistically higher estimates of fat mass compared to the non-arthritic control group cross-sectionally and over the study.Conclusion: These studies confirm the increased risk for fracture among RA patients, while providing evidence that RA alters bone strength, especially at the hip, and negatively effects body composition by reducing lean mass and increasing fat mass. Additional research is needed link structural geometry and body composition to bone strength to lead to tailored interventions to minimize decreases in bone strength in this high fracture risk population.

Long-term, high protein diets at 35% of energy may have implications in bone biology. The objective of this study was to comprehensively examine whether a high mixed protein diet at the 35% energy level can be deemed safe with respect to long-term bone health. Eighty female Sprague-Dawley rats were randomized to receive 4, 8, 12, or 17 months of a control (15% of energy as protein) or the high protein diet (35% of energy). Statistical analyses of biochemical, biomechanical, morphological, microarchitectural, and densitometric examinations using a 2-way factorial ANOVA with interaction revealed that elevated protein consumption had no negative consequences to bone health. High protein fed rats had increased lean body mass and decreased body weight and body fat. Thus preliminary results suggest that protein consumption at 35% of energy has a positive effect on body weight and does not hinder the mechanical abilities of bone.

The body composition is changing with age: the lean body mass – first of all the skeletal muscle mass and later the bone mineral content – reduces and the fat mass increases, also the regional re-distribution of fat mass occurs. The combination of low muscle mass and low muscle strength or physical performance is called sarcopenia. The aim of this study was to investigate and evaluate the body composition in elderly and the associations of body components in age-related sarcopenia. We examined 151 male and 203 female aged 60 years and older. Body composition was investigated using dual energy x-ray absorptiometry. In men with age-related sarcopenia, microbiopsy of skeletal muscle was performed. It was found that in men, the lowest lean mass and bone mineral content (BMC) were at the age of 80 years and older. In women, there were no differences in lean mass between age groups, and the lowest bone mineral content was found in the age group 80 years and older. Bone mineral content was associated with lean mass in both genders, and in women BMC also was associated with fat mass. In men with age-related sarcopenia, appendicular skeletal muscle mass was the most consistently associated with the total body, total hip and femoral neck bone mineral density (BMD). In women, the fat mass was the most significant determinant of bone mineral density. Cross-sectional area of skeletal muscle fiber was positively associated with lean mass, leg muscle mass, thigh circumference and total hip... [to full text] / Senstant kūno sudėtis keičiasi: liesoji masė – pirmiausiai skersaruožių raumenų masė ir kaulų mineralų masė – mažėja, o riebalų masė didėja ir vyksta riebalų masės regioninis persiskirstymas. Maža raumenų masė ir maža raumenų jėga arba fizinė funkcija yra vadinama sarkopenija. Siekdami ištirti ir įvertinti senų žmonių kūno sudėtį ir jos sudėtinių dalių tarpusavio sąsajas esant sarkopenijai, ištyrėme šešiasdešimties metų ir vyresnio amžiaus 151 vyrą ir 203 moteris. Kūno sudėtis buvo tirta dvisrautės radioabsorbciometrijos metodu, vyrams, kuriems nustatyta senatvinė sarkopenija, atlikta skersaruožių raumenų mikrobiopsija. Mūsų tyrimas parodė, kad vyrų liesoji masė bei vyrų ir moterų kaulų mineralų masė yra mažiausios 80 metų bei vyresnio amžiaus grupėje. Moterų liesoji masė amžiaus grupėse nesiskiria. Vyrų kaulų mineralų masė teigiamai koreliuoja su liesąja mase, o moterų kaulų mineralų masė teigiamai koreliuoja su liesąja mase ir riebalų mase. Esant senatvinei sarkopenijai vyrams galūnių raumenų masė yra reikšmingiausias veiksnys, nulemiantis viso kūno, bendrą šlaunikaulio ir šlaunikaulio kaklo KMT. Riebalų masė yra reikšmingiausias veiksnys nulemiantis moterų KMT esant sarkopenijai. Nustatėme, kad vyrų miocito plotas teigiamai susijęs su viso kūno liesąja mase, kojos raumenų mase, šlaunies apimtimi ir su bendru šlaunikaulio KMT.

The objective of this thesis was to examine age-related changes in weight and body composition as they relate to health in older adults. This thesis was completed in manuscript format and consists of two studies, both of which are based on the Cardiovascular Health Study (CHS) cohort. The CHS is a prospective cohort study of community-dwelling older (≥65 years) men and women who were followed for 8 years. The first manuscript examined whether physical activity (PA) attenuates age-related weight loss in the elderly. Mixed modeling procedures were employed to create body weight trajectory curves for the 8 year follow-up period according to physical activity level in a sample of 4512 CHS participants. Body weight declined over the follow-up period in all physical activity groups, with an accelerated weight loss occurring in the final years of follow-up. Over the 8 year follow-up, body weight was reduced by 2.72 kg in the least active PA quartile. Compared to the least active quartile, weight loss was attenuated by 0.55 kg (20%), 0.80 kg (29%), and 0.69 kg (25%) within the second through fourth physical activity quartiles. Therefore, participation in modest amounts of PA attenuated age-related weight loss by approximately 25%. The second manuscript examined whether sarcopenic-obesity is a stronger predictor of cardiovascular disease (CVD) than either sarcopenia or obesity alone, and whether muscle mass or strength is a stronger marker of CVD risk. CHS participants who were free of CVD at baseline (n=3400) were classified as normal, sarcopenic, obese, or sarcopenic-obese based on measures of waist circumference and either muscle mass or strength. Participants were followed for CVD development over 8 years and proportional hazard regression models were used to compare risk estimates for CVD after adjustment for covariates. When based on measures of waist circumference and muscle mass, CVD risk was not increased in sarcopenic, obese, or sarcopenic-obese groups in comparison to the group with a normal body composition. When categorized based on waist circumference and muscle strength, CVD risk was significantly increased (by 38%) in the sarcopenic-obese group but not in either the sarcopenic or obese groups. Thus, sarcopenic-obesity, based on muscle strength, was associated with increased CVD risk implying that strength is more important than muscle mass for cardiovascular health in old age. In summary, the findings of this thesis support the continuation of public health efforts to promote regular PA and balanced nutrition to assist with maintenance of optimal body composition and weight through adulthood and into old age. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2008-05-30 11:56:03.775

The objective of this thesis was to investigate the relationships between simple anthropometric measures and health risk towards a better characterization of the high-risk obesity phenotype. To this end, four studies were undertaken. The first study assessed the comparability of waist circumference (WC) data collected according to four commonly used measurement protocols in a sample of 520 community-dwelling men and women. This investigation quantified the influence of measurement site on the magnitude and reliability of WC and highlighted the impact of measurement site on prevalence estimates of abdominal obesity. To extend these findings, the second study examined the influence of WC measurement site on its association with cardiometabolic risk. Despite similar associations with risk factors including blood pressure, HDL-cholesterol, triglycerides, and blood glucose, prevalence estimates of metabolic syndrome differed depending on the anatomical site of WC measurement, particularly in women. In order to better understand the heterogeneity in human obesity and its sequelae, the third and fourth studies focused on the separate and combined influences of central and peripheral circumferences on health outcomes. Specifically, the third study used data from the Physical Activity Longitudinal Study (PALS) to demonstrate that after adjusting for BMI and WC, larger arm, calf, and thigh circumferences offer a protective effect against incident diabetes. The fourth study confirmed the opposing influences of central and peripheral circumferences on risk of all-cause mortality in a sample of 10,638 participants from the 1981 Canada Fitness Survey (CFS) with more than 12 y of follow-up. After adjustment for age, smoking status, alcohol consumption, leisure-time physical activity and BMI, WC was positively associated with mortality whereas arm, thigh, and calf circumferences were significantly protective in men and arm and thigh circumferences were protective in women. Collectively, the results from these studies contribute to a better understanding of the role of body dimensions in determining health risk and have implications for the use of anthropometric measures in clinical and research settings. / Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2009-04-17 14:23:44.372

The purpose was to examine the effect of body mass and body composition on the mean power output in the 30 second Wingate cycling test at five resistance settings. Forty females (X = 22 years), were divided into four groups based on body mass and the sum of five skinfolds. The Wingate test was performed at the resistance settings of 0.075, 0.080, 0.085, 0.090, and 0.095 kp/kg body weight. A 3-way ANOVA (mass, skinfolds, resistance settings) indicated that: (1) mean power (W/kg) was similar for low and high mass groups; (2) the low sum of skinfolds group had a significantly higher (p $<$ 0.02) mean power output than the high sum of skinfolds group; and (3) at resistance settings of 0.080, 0.085, 0.090, and 0.095 (kp/kg) the low sum of skinfolds group had a higher (p $<$ 0.05) mean power score than the high sum of skinfolds group at equivalent resistance settings.

The objectives of this study was to examine the efficacy and safety of graded doses of c9, t11, t10, c12 CLA isomers on body composition, energy expenditure, lipid profile and hepatic biomarkers in hamsters. Male Golden Syrian hamsters (n=105) were randomized to seven treatments (control; 1, 2, 3% of c9, t11; 1, 2, 3% of t10, c12) for 28 days. Compared with control, 1% and 3% t10, c12 had lowered food intake with all three doses of t10, c12 lowering (p<0.0001) body fat mass (g). Groups fed with 1, 2, 3% t10, c12 and 3% c9, t11 treatments showed higher lean mass compared to control and other treatment groups. However, neither body weights, nor serum HDL or triglyceride levels differed across treatment groups. The 3% t10, c12 groups exhibited higher (p<0.0001) cholesterol and LDL-C levels compared to control or other treatment groups. The 2% and 3% t10, c12 groups also presented elevated ALT level (p<0.05). The present data suggest that 3% t10, c12 possess potential adverse effects on liver and posing unfavorable change in lipid profile.

PURPOSE: To establish the reliability of anthropometric and dual energy X-ray absorptiometry(DXA) techniques used to assess percent body fat (% BF)in female athletes; to establish limits for detecting the smallest real change in % BF associated with anthropometric and DXA testing;to evaluate the validity of commonly used % BF prediction equations recommended by national certification programs along with equations derived from Multicompartment (MC), and DXA, in female athletes; and to create a new DXA based regression equation for elite female athletes. METHODS:Female athletes aged 17-31 were recruited into the study and participated in the establishment of anthropometric reliability (N=20), DXA reliability (N=32), and /or skinfold validity (N=95) testing. Anthropometric testing consisted of measurements of skinfolds,circumferences, and breadths. DXA measurements were conducted using a GE Lunar Prodigy DXA which served as the criterion measure (% BF DXA). RESULTS: Excellent reliability for both anthropometric sum5 skinfolds (ICC= .997, %TEM=0.9 %) and DXA (ICC =.996, CV =1.13% BF) techniques allows for detection of smallest real differences of 2.2 mm and 721g in summed skinfolds (sum5) and fat mass respectively. The DXA based equation of Ball et al.(2004) displayed the greatest validity of existing equations R=.874, total error (TE) 2.9% BF, and Bland Altman Limits of Agreement -4.7to 6.5 % BF. The newly created regression equation demonstrated a non-linear characteristic and displayed similar predictive ability R= .840, TE 3.0%BF, and Bland Altman Limits of Agreement of -6.1to 6.1 % BF. CONCLUSIONS: Anthropometric equations derived from various criteria yielded dissimilar results. Long utilized popular equations advocated in national accreditation schemes (ACSM, CSEP) show considerable bias compared to modern values obtained by current DXA technology. A new regression equation was created for female Canadian athletes 17-31yrs of age using skinfolds taught in the Canadian national professional certification program (CSEP).

Worldwide, overweight/obesity and associated chronic diseases such as type 2 diabetes, have reached epidemic proportions. Statistics show that overweight/obesity and chronic disease is prevalent amongst adults and children in South Africa. In addition to chronic disease/non-communicable diseases, overweight/obesity has been shown to alter immune and sympathetic activation. There is limited information on immune function (mucosal) and sympathetic activation on children both internationally and nationally and in particular investigating these parameters using non-invasive methods such as salivary biomarkers. The aim of this thesis was to investigate the levels of salivary biomarkers of immune function and sympathetic activation in children and determine the association with overweight/obesity, cardiorespiratory fitness (CRF) and increased physical activity (PA). Methods This thesis is divided into six chapters. These include an introductory chapter (Chapter One), a review of the literature (Chapter Two) and then three chapters that are written in article format and that have each been submitted to accredited journals for publication. Chapter Three is a review article that discusses salivary biomarkers in children as they relate to exercise, PA and obesity. Chapter Four is a study that examined salivary biomarkers of mucosal immunity and sympathetic activation as predicted by age, body composition and cardiorespiratory variables in one hundred and thirty-two black South African children (age 10.05 ± 1.68y, 74 females, 58 males). Chapter Five is a study that investigated salivary biomarkers of mucosal immunity and sympathetic activation in response to 12 weeks of soccer training in thirty-four black male South African children (11 – 13y) from a youth football training academy. Chapter Six includes a summary of the research findings, conclusions and well as recommendations for future research. A review of the literature revealed that participation in regular moderate intensity PA or exercise appears to enhance mucosal immunity (increases salivary IgA (sIgA)) in preadolescent children. In contrast, poor fitness and inactivity as well as strenuous training appear to compromise the mucosal immune system thereby increasing the risk of upper respiratory tract infections (URTIs). Children reporting higher levels of body fat and with a greater BMI appear to have lower sIgA levels and a greater incidence of infections. The limited research examining salivary C-reactive protein (sCRP) suggests a strong association between poor cardio-respiratory fitness (CRF) and/or overweight/obesity and inflammatory status in children based on elevated sCRP levels. Research surrounding salivary alpha-amylase (sAA) indicates that exercise can result in a marked increase in sAA as seen by an increase sympathetic activity via increased adrenergic activity in the salivary glands. The limited research suggests exercise may also pose a high stress on young athletes as seen with an increase in sAA. Additionally it appears that BMI may be a strong predictor of stress-induced sAA increases in children. Greater hypothalamic pituitary adrenal (HPA) axis response, as seen by increases in salivary cortisol, appear to be influenced greatly by increases in obesity. Higher salivary cortisol secretions have been observed in obese versus lean children in response to exercise. School study: The outcomes of the one-way ANOVAs examining the differences by body mass index (BMI) categories showed there were significant differences in weight (F = 83.64, df = 2, 129, P < 0.0001), BMI (F = 193.36, df = 2, 129, P < 0.0001), waist-to-hip ratio (F = 193.36, df = 2, 129, P < 0.0001), body fat percentage (F = 336.98, df = 2, 129, P = 0.0001), SBP (F = 5.72, df = 2, 129, P = 0.0042), DBP (F = 291.76, df = 2, 129, P < 0.0001), VO2max (F = 521.00, df = 2, 129, P < 0.0001), sAA concentration (F = 17.05, df = 2, 129, P < 0.0001), sAA secretion rate (F = 15.15, df = 2, 129, P < 0.0001), sIgA concentration (F = 11.30, df = 2, 129, P < 0.0001), and sIgA secretion rate (F = 8.08, df = 2, 129, P = 0.0005), between children of different BMI categories. According to the CDC-BMI-for-age standards, the participants were grouped into the following CDC-BMI-for-age categories: normal weight (< 85th percentile), overweight (≥ 85th percentile to < 95th percentile), and obese (≥ 95th percentile) (Ogden and Flegal, 2010). Tukey’s post hoc analyses revealed that obese children had significantly (P < 0.01) higher weight, BMI, body fat percentage, DBP, SBP, sAA concentration and secretion rate, compared to overweight and normal weight children, as well as a significantly lower aerobic capacity (VO2max) than both normal (P < 0.001) weight and overweight (P < 0.05) children. In addition, sIgA concentration and secretion rate were significantly lower between normal weight and obese children (P < 0.01). Multiple linear regression revealed that BMI, DBP and VO2max predicted sAA. BMI (P = 0.04) and DBP (P = 0.04) were found to be independent predictors of sAA concentration. Age and BMI category predicted sIgA secretion rate. BMI category (P = 0.0006) was found to be an independent predictor of sIgA secretion rate. Soccer study: Significant differences after 12 weeks of soccer specific training were found to be significant between pre vs. post for BMI (P =0.034), waist-to-hip ratio (P = 0.046), age (P < 0.0001), height (P < 0.0001), body fat % (P < 0.0001) and LMM (P < 0.0001). Decreases in BMI, waist-to-hip ratio, body fat % and LMM were found while age and height increased throughout the 12 weeks. Significant differences were also found between sIgA secretion rate pre vs. post training (P =0.025) as increases in these values pre to post were observed. Conclusions The results from the studies on the school children and soccer players suggested that mucosal immune function and sympathetic activation appear to be affected by body composition, CRF and chronic exercise training. The main findings for the school study revealed that BMI, DBP and VO2 predict sAA and that age and BMI category predict sIgA. This study also found that obesity (based on BMI) has a major role to play and that obese children have elevated sAA, lowered sIgA, and poor CRF. The finding of an increase in sIgA secretion rate in the soccer study suggested that a structured 12 week exercise programme can elevate mucosal immune function in youth soccer players. The underlying mechanism responsible may be an exercise-induced increase in the transport of sIgA across the mucosal epithelium and/or enhanced production of IgA in the mucosa via mediating cytokines. The literature review demonstrated that PA and overweight/obesity may have an impact on salivary biomarkers of mucosal immunity and sympathetic activation in children, however further research with regards to optimal intensity, duration and modality need to be assessed in the pre-pubescent population.Physical activity, obesity, immunity, neuro-endocrine, children, salivary biomarkers, sympathetic activation. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.

The purpose of this study was to examine the effects of hydration status on the prediction of body composition using BIA, NIR, and DEXA. Twenty healthy males and females ages 18 to 28 were recruited for this study. The subjects were dehydrated in the climate control chamber and engaged in physical exercise, until they lost approximately 1%, 2%, and 3% of their pre-exercise body weight. Percent body fat (%BF), body weight, and urinalysis measures were taken initially on day 1, on day 4 at euhydration, following 1%, 2%, and 3% dehydration, and upon rehydration during day 5. The results indicated that there were significant decreases for %BFBIA and %BFNIR between euhydration and 1%, 2%, and 3% dehydration. %BFDExA did not significantly change.There were also significant differences in the response to dehydration between each technique. Proper hydration should be ensured before %BF is estimated with BIA and NIR. / School of Physical Education