Browsing by Subject "obesity"

Now showing 1 - 8 of 8
  • Thumbnail Image
    Item
    Open Access
    Adolescents’ Perspectives on the Drivers of Obesity Using a Group Model Building Approach: A South African Perspective
    (2022-02-14) Hendricks, Gaironeesa; Savona, Natalie; Aguiar, Anaely; Alaba, Olufunke; Booley, Sharmilah; Malczyk, Sonia; Nwosu, Emmanuel; Knai, Cecile; Rutter, Harry; Klepp, Knut-Inge; Harbron, Janetta
    Overweight and obesity increase the risk of a range of poor physiological and psychosocial health outcomes. Previous work with well-defined cohorts has explored the determinants of obesity and employed various methods and measures; however, less is known on the broader societal drivers, beyond individual-level influences, using a systems framework with adolescents. The aim of this study was to explore the drivers of obesity from adolescents’ perspectives using a systems approach through group model building in four South African schools. Group model building was used to generate 4 causal loop diagrams with 62 adolescents aged 16–18 years. These maps were merged into one final map, and the main themes were identified: (i) physical activity and social media use; (ii) physical activity, health-related morbidity, and socio-economic status; (iii) accessibility of unhealthy food and energy intake/body weight; (iv) psychological distress, body weight, and weight-related bullying; and (v) parental involvement and unhealthy food intake. Our study identified meaningful policy-relevant insights into the drivers of adolescent obesity, as described by the young people themselves in a South African context. This approach, both the process of construction and the final visualization, provides a basis for taking a novel approach to prevention and intervention recommendations for adolescent obesity.
  • Thumbnail Image
    Item
    Open Access
    Depot differences in adipose tissue metabolism and function in obese black South African women and changes in response to an exercise training intervention
    (2020) Nono Nankam, Pamela Arielle; Goedecke, Julia
    Black South African (SA) women are disproportionally affected by obesity and insulin resistance, which have been associated with depot-specific alterations in adipose tissue function. This thesis aimed to evaluate the differences in fatty acid (FA) composition and gene expression between abdominal (aSAT) and gluteal subcutaneous adipose tissue (gSAT), and the changes in response to exercise training in relation to body composition, hepatic fat, inflammatory and oxidative stress markers, and insulin sensitivity (SI) in obese black SA women. This research evaluated the i) FA composition of aSAT and gSAT, and red blood cell total phospholipids (RBC-TPL) and their associations with body composition, hepatic fat and SI, ii) changes in these FA profiles in response to exercise training and the relationship with changes in systemic inflammation, hepatic fat and SI; iii) effects of exercise training on systemic markers and SAT gene expression of inflammation and oxidative stress; and iv) regional differences in transcriptome profiles of aSAT and gSAT pre- and post-exercise training. Forty-five IsiXhosa women (30-40kg/m2 , 20-35 years) were randomized into control (n=22) or exercise groups (n=23; 12-week aerobic-resistance training, 40-60 min/session, 4 days/week). Pre and postintervention measurements included: anthropometry, body composition, cardiorespiratory fitness, dietary intake, SI, hepatic fat, systemic markers and SAT gene expression of adipokines, inflammation and oxidative stress, RBC-TPL and SAT fatty acids profiles, and untargeted SAT gene expression analyses. The main findings showed differences in the circulating (RBC-TPL) and stored (SAT) FA composition, which reflected in different associations between these FA profiles and SI. Moreover, the changes in FA composition in response to exercise training were depot-specific, with the changes in RBC-TPL correlating with a decrease in systemic inflammation and hepatic fat. Exercise training alleviated systemic oxidative stress and induced increased gSAT inflammatory genes, reflecting SAT remodelling. These changes coincided with a reduction in gynoid fat and were not associated with increased SI. Furthermore, there were unique depot-specific gene expression signatures relating to embryonic development at baseline and more diverse functional-related processes at post-training. This generated novel candidate genes potentially implicated in the relationship between body fat distribution and metabolic status in obese black SA women.
  • Thumbnail Image
    Item
    Open Access
    Fat mass and obesity associated (FTO) gene influences skeletal muscle phenotypes in non-resistance trained males and elite rugby playing position
    (2017) Heffernan, S M; Stebbings, G K; Kilduff, L P; Erskine, R M; Day, S H; Morse, C I; McPhee, J S; Cook, C J; Vance, B; Ribbans, W J; Raleigh, S M; Roberts, C; Bennett, M A; Wang, G; Collins, M; Pitsiladis, Y P; Williams, A G
    Abstract Background FTO gene variants have been associated with obesity phenotypes in sedentary and obese populations, but rarely with skeletal muscle and elite athlete phenotypes. Methods In 1089 participants, comprising 530 elite rugby athletes and 559 non-athletes, DNA was collected and genotyped for the FTO rs9939609 variant using real-time PCR. In a subgroup of non-resistance trained individuals (NT; n = 120), we also assessed structural and functional skeletal muscle phenotypes using dual energy x-ray absorptiometry, ultrasound and isokinetic dynamometry. In a subgroup of rugby athletes (n = 77), we assessed muscle power during a countermovement jump. Results In NT, TT genotype and T allele carriers had greater total body (4.8% and 4.1%) and total appendicular lean mass (LM; 3.0% and 2.1%) compared to AA genotype, with greater arm LM (0.8%) in T allele carriers and leg LM (2.1%) for TT, compared to AA genotype. Furthermore, the T allele was more common (94%) in selected elite rugby union athletes (back three and centre players) who are most reliant on LM rather than total body mass for success, compared to other rugby athletes (82%; P = 0.01, OR = 3.34) and controls (84%; P = 0.03, OR = 2.88). Accordingly, these athletes had greater peak power relative to body mass than other rugby athletes (14%; P = 2 x 10 -6 ). Conclusion Collectively, these results suggest that the T allele is associated with increased LM and elite athletic success. This has implications for athletic populations, as well as conditions characterised by low LM such as sarcopenia and cachexia.
  • Thumbnail Image
    Item
    Open Access
    Genotype-based personalised nutrition for obesity prevention and treatment: are we there yet?
    (MedPharm Publications, 2012) Senekal, Marjanne
    Interactions between genotype and dietary intake include genetic moderation of the effect of dietary intake on disease development (nutrigenetics). Research on nutrigenetics has focused mainly on single-nucleotide polymorphisms (SNPs) and supports the notion that interactions between genes, diet, other lifestyle factors, disease, and time (life cycle span), contribute to the risk of most polygenic nutritionrelated diseases. Typically, genotype-based personalised nutrition involves genotyping for a number of susceptibility SNPs associated with the prevention, or management, of a particular disease. Dietary advice is then personalised to the individual's genotype to ensure optimal prevention or treatment outcomes. To ensure evidence-based practice, research design and methodology, applied in the investigation of relevant associations, and confirmation of causality, should be appropriate and rigorous. The process of identifying SNPs associated with disease patterns is ongoing. Of note is that the combined effect on body mass index of the SNPs at the currently confirmed 32 loci is a modest 1.45%, bearing in mind that the estimated heritability of obesity is 40-70%. Conclusions formulated by various researchers on the translation of nutrigenetics research into personalised nutrition, including obesity prevention and management, indicate that scientists hold the opinion that more research is necessary before evidence-based practice in this area can be guaranteed.
  • Thumbnail Image
    Item
    Open Access
    Healthy lifestyle interventions in general practice Part 10: Lifestyle and arthritic conditions - Osteoarthritis
    (South African Academy of Family Physicians, 2010) Schwellnus, M P; Patel, D N; Nossel, C; Dreyer, M; Whitesman, S; Derman, E W
    Chronic musculoskeletal disease is one of the most common causes of disability worldwide with considerable economic impact in health care. Osteoarthritis (OA) is the most common chronic musculoskeletal disease affecting a large proportion of the population with an increasing predicted prevalence in the next two decades. Regular physical exercise, nutritional intervention, psychological support and other lifestyle interventions are very important components of the nonpharmacological management of patients with OA. The main rationale to include regular exercise as part of a lifestyle intervention programme for OA is to improve muscle strength and proprioception, and to promote the other general health benefits of participating in regular physical activity. Nutritional intervention should focus on weight reduction while basic nutrients that are required for healthy joints should be provided. Glucosamine and chondroitin supplemention is commonly used and may reduce pain, improve function and reduce or arrest disease progression. Psychological intervention has a particular role in assisting with pain management.
  • Thumbnail Image
    Item
    Open Access
    Healthy lifestyle interventions in general practice: Part 14: Lifestyle and obesity
    (South African Academy of Family Physicians, 2011) Derman, E W; Whitesman, S; Dreyer, M; Patel, D N; Nossel, C J; Lambert, E V; Schwellnus, M P
    Obesity is defined as an excessive amount of body fat or adiposity. It can be measured using the body mass index (BMI), and according to established criteria for adult men and women, overweight is defined as a BMI between 25-30 kg/m2, and obesity as a BMI > 30 kg/m2. Obesity is clinically associated with many serious co-morbidities, and is widely recognised as one of the leading health threats in most countries around the world. Weight loss is recommended for patients with a BMI > 25 kg/m2. The goals of weight loss therapy are to reduce obesity-related co-morbidities and decrease the risk of future obesity-related medical complications. The management of obesity is multifactorial, and involves the use of combined lifestyle interventions, including regular physical activity and dietary and psychosocial intervention. Practical clinical advice regarding interventions in these important areas is provided in this article.
  • Thumbnail Image
    Item
    Open Access
    Obesity phenotypes in urban and rural Cameroonians: a cross-sectional study
    (BioMed Central Ltd, 2015) Mbanya, Vivian; Echouffo-Tcheugui, Justin; Akhtar, Hussain; Mbanya, Jean-Claude; Kengne, Andre
    BACKGROUND: Despite the increasing prevalence of diabetes and other health consequences of obesity, little is known on the metabolic profile across categories of body mass index (BMI) among African populations. We therefore assessed the prevalence and distribution of body size phenotypes among urban and rural Cameroonians. METHODS: Adults (n=1628; 41% rural dwellers) aged 24-74 years in 1994 provided data on BMI and metabolic health, defined on the basis of elevated levels of blood pressure (BP); triglycerides, fasting plasma glucose (FPG), and insulin resistance as assessed with homeostasis model assessment (HOMA). Cross-classification of BMI categories and metabolic status (healthy/unhealthy) created six groups. Metabolic measures include elevated blood pressure; elevated triglycerides ([greater than or equal to]150 mg/dL or 1.69mmo/L), elevated fasting plasma glucose ([greater than or equal to]100 mg/dl or 5.6 mmol/L or documented use of antidiabetic medications), and elevated homeostasis model assessment of insulin resistance value (HOMA-IR>90th percentile). RESULTS: A total of 25.2% of participants were overweight yet metabolically healthy (<1 abnormality) and 10.1% were obese yet metabolically healthy, whereas 1.4% were normal weight but metabolically abnormal ([greater than or equal to]2 abnormalities). Proportion of rural dwellers with abnormal metabolic phenotype across normal-weight, overweight, obese categories were 2.9%, 0.8% and 0.3%, respectively; and 0 .3%, 2.2% and 2.6% among urban dwellers. Metabolically abnormal participants increased linearly across BMI categories (p<0.001). BMI categories and metabolic status interacted to affect age, gender, BMI, FPG, triglycerides, and BP status distributions (all p<0.04). Metabolic status and residence (rural vs. urban) interacted to influence the distribution across BMI categories of diastolic BP, BMI, waist circumference, fasting and 2-hour glucose, triglycerides, HOMA-IR, and prevalent diabetes (all p<0.005), with differential occurrence of BMI categories and metabolic status among urban and rural participants. CONCLUSIONS: Metabolic healthy obesity and obesity with a favorable cardiometabolic profile are not uncommon among Cameroonians, including among rural dwellers; but the latter group tended to have a better profile.
  • Thumbnail Image
    Item
    Open Access
    Overweight, obesity, underweight and stunting in female primary school learners in rural KwaZulu-Natal, South Africa
    (2013) Tathiah, N; Moodley, I; Mubaiwa, V; Denny, L; Taylor, M
    Background. Malnutrition substantially impacts the health outcomes of children. Globally, the childhood prevalence of overweight and obesity has increased, while underweight and stunting (though decreasing) continues to pose a major public health challenge. In low- to middle-income countries, a mixed pattern of over- and undernutrition (nutritional transition) can exist in communities. Objective. To describe the prevalence of malnutrition among female learners in the Nongoma and Ceza districts in Zululand, KwaZulu-Natal (KZN). Methods. We performed a secondary analysis of anthropometric data collected during the 2011 HPV Vaccination Demonstration Project. School health teams, comprising trained nurses, measured the height (in cm) and weight (in kg) of 963 female learners in 31 primary schools. Internationally accepted standardised measures were used as cut-offs for defining overweight, obesity, underweight and stunting. Results. We found evidence of both under- and overnutrition. Overall, 9% of female learners were overweight, 3.8% obese, 4% underweight and 9.2% stunted (using WHO/NCHS criteria). The highest levels of stunting were in the 11 - 12-year age groups, of underweight in the 10-year age group, of overweight and obesity in the 9 - 10-year age groups. Moreover, a proportion of underweight (17.4%), overweight (11.1%) and obese (22.9%) learners were also stunted. Conclusion. Our study describes the prevalence of overweight and obesity, wasting and stunting of female learners in KZN and suggests the presence of a nutritional transition in these rural communities; however, further studies are needed. Our findings emphasise the need for health promotion and education programs in schools.