The association between physical activity, body composition and cardio-metabolic disease risk in middle-aged men from Soweto

Abstract

South Africa has the highest obesity prevalence in sub-Saharan Africa, and this is associated with a high prevalence of metabolic syndrome (MetS). Regular physical activity has been shown to reduce obesity and the risk of cardio-metabolic diseases such as hypertension and diabetes. The aim of this dissertation was to investigate the associations between objectively measured physical activity, sedentary behaviour and sleep, and the MetS and its components, in middle-aged black South African men, and to determine whether this relationship was independent of body mass index (BMI). The participants included in this study comprised a sub-sample of men (n=286, mean age 56.6±6.3 years) who were part of a larger study. Socio demographic factors (age, level of education, employment status, marital status, and socioeconomic status) were obtained via questionnaire. Participants underwent the following measurements: weight, height, waist circumference, blood pressure, fasting blood glucose, HDL-C, LDL-C, Triglycerides. Thereafter, physical activity was measured by accelerometer (Actigraph GT3X-plus) using Troiano (2008) cut-points. Participants spent on average 35% of the day in sedentary behaviours. However, 75% of study participants met WHO physical activity recommendations (engaging in at least 150 minutes of moderate intensity activity per week or 75 minutes of vigorous intensity activity per week). Sedentary time was significantly associated with higher odds of having MetS (OR≥1.004 (1.00-1.00) p≤0.000, however when adjusted for BMI, it was no longer significant p=0.499. Moderate to vigorous intensity physical activity (MVPA) and daily step count were both significantly associated with lower odds of metabolic syndrome, however after adjusting for BMI, daily step count was no longer significant. Promotion of physical activity while reducing sedentary time should be encouraged to reduce obesity and cardio-metabolic disease risk outcome and type 2 diabetes