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)

Maidment, Catharina Maria (2016-03)

Thesis (MNutr)--Stellenbosch University, 2016.

Thesis

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.

AFRIKAANSE OPSOMMING : Inleiding: Beroepgesondheidsverpleegkundiges werksaam by Life Gesondheidsdienste het waargeneem dat die voorkoms van hipertensie toeneem onder die werknemers sedert hulle by Hotazel Mangaanmyne begin werk het. Uit die 804 werknemers wat geskik was vir die studie, het 369 alreeds hipertensie gehad tydens indiensname by Hotazel Mangaanmyne. Doelwitte: Die studie het gepoog om vas te stel of voeding- en lewenstyl moontlike risikofaktore kon wees vir die oënskynlike hoë voorkoms van hipertensie onder mynwerkers. Risiko faktore wat verband hou met diëet (oormatige sout lae kalium, magnesium, kalsium, hoe versadigde vette en energie, ongesonde diëet en alkohol inname) en lewenstyl (fisiese onaktiwiteit, spanning, rook, en vetsug) is ondersoek. Aanbevelings om hipertensie onder die werknemers te voorkom en te bestuur is gemaak volgens die bevindinge. Metodologie: ’n Analitiese ongepaarde geval en kontrole studietipe is gebruik. Die werknemers wat in aanmerking gekom het vir seleksie het bestaan uit 408 permanente manlike werknemers wat sonder hipertensie was tydens indiensname. Proporsionele ewekansige steekproeftrekking is aanvanklik gebruik om werknemers by drie myne te kies. Deelnemers is geselekteer volgens die Suid-Afrikaanse Hart- en Beroerte Stigting se klassifikasie van hipertensie. Elke deelnemer se antropometriese data en bloeddrukwaardes tydens indiensname en elke jaar daarna, is uit die mediese lêers verkry. Die deelnemers het vraelyste oor hulle fisiese aktiwiteit, spanningsvlakke en sosio-demografie ingevul. ’n Gekwantifiseerde voedselfrekwensie vraelys is deur die navorser tydens individuele onderhoude gebruik (insluitende vrae oor ekstra sout toevoeging, alkohol inname en rookgewoontes). Die voedingsinligting is geanaliseer met behulp van die Foodfinder voedingsanalise sagteware. Statistiese analise is uitgevoer deur die gebruik van verskeie metodes en ’n p-waarde van p<0.05 is aanvaar as statisties beduidend. Resultate: Tydens ’n gemiddelde dienstydperk van 11 jaar by Hotazel Mangaan Myn, het 58% (n=26) van die deelnemers hipertensie ontwikkel (hipertensiewe gevalle) en 42% (normotensiewe kontrole) het nie. Die hipertensiewe gevalle het beduidend langer gewerk (p<0.01) as die normotensiewe kontrole (14 jaar teenoor 6 jaar onderskeidelik) en was ook beduidend ouer (p=0.03) as die normotensiewe kontrole (42 jaar teenoor 36 jaar onderskeidelik). Liggaamsmassa indeks (LMI) het gedurende die dienstydperk met 3 kg/m2 toegeneem en die gevalle (n=26) het ’n beduidende hoër toename in LMI gehad gedurende die dienstydperk (p=0.004). Die kleurling deelnemers in meer senior posisies was beduidend meer waarskynlik om hipertensie te ontwikkel as die kleuringdeelnemers in laer posisies (p=0.01). Wit deelnemers werksaam op Mamatwan myn was meer waarskynlik om hipertensie te ontwikkel (p=0.01). Daar was geen beduidende verskil tussen die twee groepe in terme van dienstydperk voordat die gevalle hipertensie ontwikkel het (gemiddeld drie jaar), die vlak van fisiese aktiwiteit, spanningsvlakke, alkohol inname, rookgewoontes, gebruik van diëetaanvullings, byvoeging van ekstra sout en hoeveelheid natrium, magnesium, kalium, kalsium, versadigde vet en energie ingeneem nie. Die gemiddelde energie-inname asook versadigde vet-inname was meer as die aanbevole daaglikse toelae. Gevolgtrekking: Die tydperk van indiensname, ’n toename in ouderdom en ’n toename in LMI was geassosieer met die ontwikkeling van hipertensie in hierdie studie. Leefstyl intervensies moet ingestel word om gesondheid en algemene welstand van die werknemers van Hotazel Mangaanmyn te bevorder.

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