Philosophiae Doctor - PhD / Background: There is compelling body of evidence that coronary heart disease (CHD)
risk factors are present in people of all ages. The extent to which the problem exists in
university students in South Africa (SA) has not been confirmed in the literature. Furthermore, the effects of physical activity, physical fitness, diet and health behaviours
on CHD risk factors has not been studied extensively in SA and needs further
investigation. Aim: The aim of the study was to assess the impact of multiple behaviour health intervention strategies on CHD risk, health-related physical fitness(HRPF) and healthrisk behaviours (HRB) in first year students at the University of the Western Cape
(UWC). It was hypothesized that exposure to various health behavioural interventions
would reduce CHD risk factors in subjects at moderate risk, and improve health-related
physical fitness, as well as health-risk behaviours.Methods and Study Design: An experimental study design was used wherein subjects at moderate risk for CHD were identified and exposed to multiple health behavioural interventions for 16 weeks in order to determine the impact of the various interventions on CHD risk, health-related physical fitness and health-risk behaviours. Population and Sample: The target population consisted of first year students at UWC aged 18 – 44 years who were screened and a sample of 173 subjects were identified as being at moderate risk for CHD. Next, the subjects were randomly assigned to a control and four treatment groups, namely, health information, diet, exercise, and a multiple group that included all three treatments. The intervention, based upon Prochaska‟s Transtheoretical Model of behaviour change, continued for a period of 16 weeks and, thereafter, the subjects were retested. Data Collection Process: Subject information was obtained using self-reported questionnaires, namely, the physical activity readiness questionnaire (PAR-Q), the stages of readiness to change questionnaire (SRCQ), the international physical activity questionnaire (IPAQ), and the healthy lifestyle questionnaire (HLQ), together with physical and hematological (blood) measurements. The measurements taken before and after the intervention programme were the following:• Coronary heart disease risk factors, namely: family history, cigarette smoking, hypertension, obesity, dyslipidemia, impaired fasting glucose and a sedentary lifestyle; • Health-related physical fitness, namely: body composition, cardiovascular fitness, muscular strength, muscular endurance, and flexibility; and • Health-risk behaviours, namely: physical activity, nutrition, managing stress, avoiding destructive habits, practising safe sex, adopting safety habits, knowing firstaid, personal health habits, using medical advice, being an informed consumer, protecting the environment and mental well-being. Types of interventions: A control group was used in which subjects did not receive any treatment. The health behavioural interventions were arranged into four groups of subjects that received either the health information, diet, exercise or a combination of all three individual treatments. Statistical analyses of data: In the analyses of the data, the procedure followed was that where the outcome variable was approximately normally distributed, the groups were compared using a two-sample t-test. For outcomes with a highly non-normal distribution or ordinal level data, the nonparametric Wilcoxon Rank Sum test was used for group comparisons. To account for baseline differences, repeated measures analysis of variance was used. In the case where nonparametric methods were appropriate, analysis was done using Cochran-Mantel-Haenszel (CMH) methodology stratifying on the baseline values. For the case of nominal level outcomes, groups were compared by Chi-square tests for homogeneity of proportions. When baseline values needed to be incorporated into the analysis, this was done using CMH methodology. Main Outcome Measures: The main outcome measures tested in the study related to the three areas of investigation, namely: • Modifiable CHD risk factors: systolic and diastolic blood pressure, cigarette smoking, total cholesterol (TC) concentration, high-density lipoprotein (HDL) cholesterol concentration, low-density lipoprotein (LDL) cholesterol concentration, triglycerides, fasting glucose, body mass index, waist circumference, waist-hip ratio and physical inactivity; • Health-related physical fitness: body mass, percent body fat, absolute body fat, percent lean body mass, absolute lean body mass, the multi-stage shuttle run, handgrip strength, repeated sit-ups in a minute, and the sit-and-reach test; and • Health-risk behaviours: physical activity, nutrition, managing stress, avoiding destructive habits, practising safe sex, adopting safety habits, knowing first aid, personal health habits, using medical advice, being an informed consumer, protecting the environment and mental well-being. Results: The results showed significant decreases for body mass, waist and hip circumferences, resting heart rate, systolic blood pressure, cigarette smoking and a sedentary lifestyle (p < .05) primarily in the multiple group. No significant differences were recorded for blood biochemistry, however, favourable trends were observed in the lipoprotein ratios. For health-related physical fitness, only the multiple group showed significant (p < .005) improvements in predicted maximal oxygen consumption ( O2max), body composition, muscular strength and muscular endurance. The exercise group also recorded significant differences in muscular endurance. In all groups, including the controls, no significant differences were found for stature, waist-hip ratio, and flexibility at pre- and post-test. Overall, the participants reflected positive health behaviours, especially for managing stress, avoiding destructive habits, practising safe sex, adopting safety habits, personal health habits and mental well-being at pre- and post-test. The intervention programme had a corrective influence on providing the participants with a more realistic perception of their level of physical activity and nutritional habits. The participants scored poorly on being informed consumers and for recycling waste both at pre- and post-test. A substantial net reduction in CHD risk factors as well as in cumulative risk was achieved with treatment that impacted positively on the re-stratification of participants at moderate risk. In terms of treatment efficacy, the dietary intervention appeared to be the least effective (10.91%), with health information and exercise sharing similar levels of efficacy (32.81% and 33.93%, respectively) and, the combined treatment in the multiple group stood out as the most effective treatment (50.00%), and supported the hypothesis of the study. Conclusions: The net and cumulative decline in CHD risk factors was substantial with treatment and was directly related to the number of treatments administered. The evidence suggests that such multiple health behaviour interventions when implemented through a university-based setting have substantial benefits on reducing CHD risk and may be of considerable public health benefit. Key messages • Despite being a relatively educated population, a substantial number of first year university students are at considerable heart disease risk. • Physical inactivity constitutes one of the main CHD risk factors amongst first year students and, together with smoking, place many of them at moderate CHD risk. • The effectiveness of health behavioural strategies designed to modify lifestyle and prevent coronary heart disease is supported by this study.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/5302 |
| Date | January 2011 |
| Creators | Leach, Lloyd L |
| Contributors | Travill, Andre |
| Publisher | University of the Western Cape |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Rights | University of the Western Cape |
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