Physical activity status and the relationship between non-communicable diseases risk factors in an urban South African teachers cohort : 'the SABPA study B

Abstract

Introduction: Non-communicable diseases (NCDs) are chronic diseases caused by unhealthy lifestyle decisions and account for the majority of deaths per year globally. NCD incidence is increasing rapidly and NCDs are becoming an epidemic. The main NCDs include obesity, hypertension, diabetes mellitus (DM) and cancer. The relationship between physical activity (PA), health, and longevity is one that has been recognized by historical figures for centuries. The aim of this study is thus to investigate the prevalence of NCDs in male and female, African and Caucasian teachers and to determine the association between PA and NCD prevalence in African and Caucasian teachers in the North West Province of South Africa. Method: A total of 216 African and Caucasian South African school teachers were recruited in the North West Province of South Africa (African men n=52; African women n=57; Caucasian men n=52 and Caucasian women n=55). The following measurements were included for the purpose of this study: seven-day objectively measured PA status in PAL 1-5, which is categorized as PAL 1 and 2 (sedentary), PAL 3 (semi active), PAL 4 (Active) and PAL 5 (vigorous active); cardio metabolic risk factors [body mass index (BMI), waist circumference (WC), 24-hour systolic (SBP) and diastolic blood pressure (DBP), fasting lipid profile (total cholesterol (TC), low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides (TG)] and fasting glucose (FG). Data analyses were performed using SPSS version 20. Interaction on main effects (gender x ethnicity) was tested with a 2 X 2 ANOVA in order to determine significant differences in variables. Departure from normality was evaluated through the Levene test for equality of variances and skewed data was normalised. Forward stepwise regression was undertaken so as to determine associations between the different variables within and between the four groups with adjustments for age, gender, and ethnicity. The Pearson correlation coefficient was used to determine any relationships between variables and different groups. Frequency risk factors were calculated within the different groups as well as within the PA groups and chi-square statistics were used to calculate the frequencies of variables between the groups. The frequency of each risk factor was then calculated to determine the prevalence within each category of PA status. Statistical significance was set at a two-sided alpha () level of 0.05 or less. Results: The risk factors for NCDs across the entire group were prevalent in the following order: WC (72.22%), hypertension (57.87%), physical inactivity (39.4%), elevated BMI (38.88%), low HDL Cholesterol levels (37.96%), elevated TG (18.98%) and elevated FG (17.13%). The PAL status of the entire group was classified as highly active with the highest PA status profile prevalence in PAL 3-5 (60.7%), and the highest prevalence being found in PAL 4 (21.3%) and PAL 5 (24.1%). 39.3% of participants fell within the sedentary group (PAL 1 and 2). Both male groups (African males and Caucasian males) presented with the lowest PAL, with 50% of the combined male group falling within either PAL 1 or 2, this is followed by Caucasian females, with 34.5% of the group falling within either PAL 1 or 2. African females were seen to be the most active with 75.5% of the group falling within PAL 3 to 5, followed by Caucasian females with 65.5% of the group falling within PAL 3 to 5 (Figures 4.5 A-D). Physical inactive participants presented with a 2.54 times higher probability of an increased WC, a 1.153 times higher probability of an increased FG, a 1.116 times higher probability of an increased TG, a 0.919 times higher probability of a decreased HDL cholesterol value, a 2.338 times higher probability of an elevated SBP and a 1.874 times higher probability of an increased DBP as compared to active participants. Significant differences were noted between the four groups‟ BMI (p≤0.001), WC (p≤0.001), TEE (total energy expenditure) (p=0.030), FG (p≤0.001), TC (p≤0.001), HDL cholesterol (p=0.001), TG (p≤0.001), SBP (p≤0.001) and DBP (p≤0.001). African men were the most vulnerable group as concerns the prevalence of NCD risk factors with participants having three out of six (50%) risk factors. Discussion: Various researchers have suggested that an increase in PA status can have a positive effect on overall health with a decreased risk for NCDs. However, the current study could not confirm previous research findings. In theory, the risk factors of NCDs decline with an increase in PA, in line with previous research. In the current study, all participants presented with a very high prevalence of inactivity, with the most active groups, African females, Caucasian females, and Caucasian males, showing a higher prevalence of risk factors within the physically inactive subgroup as compared to the physically active subgroup. African males presented with a lower prevalence of risk factors in the active subgroup as compared to the inactive subgroup, even though the prevalence of risk factors overall is the highest within the African males. Reducing the prevalence of NCDs can lead to improved future health, improved life expectancy, and improved productivity on a national scale. It may therefore be beneficial to implement strategies geared at increasing PA in the daily lives of all South African teachers. Biokineticists and/or exercise therapists may be able to use the information gathered from this study so as to increase awareness regarding PA status and the risks for NCDs engendered by physical inactivity in this population. Conclusion: An alarmingly high prevalence of NCD risk factors is evident in all four of the groups. While most of these risk factors can be modified, the risk factors seem to be ignored and it is therefore of utmost importance that people be educated as concerns the negative effects of risk factors and how to reduce their risk profile. (940)