An investigation of possible contributing risk factors related to diet and lifestyle which may cause hypertension in male employees of Hotazel Managanese mines (Northern Cape Province, South Africa)

[摘要] ENGLISH SUMMARY : Introduction:Occupational health nurses employed by Life Health Services noticed a high prevalence of hypertension among employees that were hypertension free at the start of employment at Hotazel Manganese Mines. Of the 804 employees eligible for participation in the study, 369 already suffered from hypertension at commencement of employment.Objectives: This study investigated nutrition and lifestyle as risk factors for the perceived high prevalence of hypertension among the male mineworkers. Risk factors relating to diet were investigated (excessive salt consumption, a reduced intake of potassium, magnesium, calcium, high saturated fat and energy intake; overall unhealthy diet and alcohol consumption) and lifestyle (physical inactivity, stress, smoking and obesity). Findings assisted in developing a set of recommendations to help prevent and manage the development of hypertension in employees of HMM.Methodology: An analytical unmatched case-control study type was used. The eligible sample consisted of 408 permanent male employees who were hypertension free at the start of employment. Proportionate random sampling methods were initially used to select participants from three mines (N=88). Participants were selected using the South African Heart and Stroke Foundation's classification for hypertension. Anthropometric data was obtained from each participant's medical file as well as their blood pressure at the start of employment and yearly measurements thereafter. Participants completed self-administered questionnaires pertaining to their physical activity, stress and demographic information. The researcher administered the quantified food frequency questionnaire (including questions on extra salt addition, alcohol intake and smoking) during individual interviews and analysed the nutritional content using the Foodfinder nutritional analysis software. Statistical analysis was performed using various methods and a p-value of <0.05 was regarded as statistically significant.Results: Fifty eight per cent (n=26) of the participants developed hypertension during employment at Hotazel Manganese Mines (hypertensive cases) and 42% (n=19) remained normotensive (controls) during an average of 11 years of employment. The cases have, on average, worked significantly longer (p<0.01) than the controls (14 years compared to six years respectively) and were also significantly older (p=0.03) than the controls (42 years and 36 years respectively). Body mass index (BMI) increased on average with 3 kg/m2 during employment and the cases (n=26) had a significantly higher increase in BMI during employment (p=0.004). Coloured participants in more senior positions were significantly more likely to develop hypertension than the coloured participants employed in lower levels (p=0.01). White participants working at Mamatwan mine were more likely to develop hypertension (p=0.01). No significant difference was found between the two groups in terms of the amount of time it took the cases to develop hypertension during employment (on average three years), the level of physical activity, stress levels, alcohol consumption, smoking, supplement usage, addition of extra salt, consumption of sodium, magnesium, potassium and calcium, saturated fat and energy intake. Mean energy and saturated fat intake was higher than the recommended dietary allowances.Conclusion: Duration of employment, increased age and BMI increase was associated with the risk of developing hypertension in this study. Lifestyle interventions should be introduced to improve the health and well-being of the employees.

[发布机构] Stellenbosch University