Objectives: The study aimed to assess health status and identify distinct risk-factor profiles for both chronic lifestyle diseases and metabolic syndrome in rural and urban communities in central South Africa.

Methods: The investigation formed part of the Assuring Health for All in the Free State (AHA-FS) study. During interviews by trained researchers, household socio-demographic and health information, diet, risk factors (i.e. history of hypertension and/or diabetes) and habits (e.g. smoking and inadequate physical activity levels) were determined. Adult participants underwent anthropometric evaluation, medical examination and blood sampling.

Results: The risk-factor profile for chronic lifestyle diseases revealed that self-reported hypertension and physical inactivity were ranked the highest risk factor for the rural and urban groups respectively. The cumulative risk-factor profile showed that 40.1% of the rural and 34.4% of the urban study population had three or more risk factors for chronic lifestyle diseases. Furthermore, 52.2% of rural and 39.7% of urban participants had three or more risk factors for metabolic syndrome.

Présentation: Les maladies chroniques liées au style de vie présentent des facteurs de risque modifiables similaires, notamment l’hypertension, le tabagisme, le diabète, l’obésité, l’hyperlipidémie et la sédentarité. Le syndrome métabolique fait référence à l’ensemble de facteurs de risque incluant le risque de développement de diabète sucré de type 2 et de maladie cardiovasculaire.

Objectifs: L’objectif de l’étude était d’évaluer l’état de santé et d’identifier les profils de facteurs de risque distincts pour les maladies chroniques liées au style de vie et pour le syndrome métabolique dans les communautés de la région centrale de l’Afrique du Sud.

Méthodes: L’étude faisait partie de l’étude intitulée « Assurer la santé pour tous dans l’Etat libre (AHA-FS) ». Au cours des entretiens menés par des chercheurs formés, les informations sociodémographiques et sanitaires, les régimes alimentaires, les facteurs de risque (c.à.d. les antécédents d’hypertension et/ou de diabète) et les habitudes (par ex. le tabagisme et des niveaux d’activité physique inadéquats) ont été déterminés. Les participants adultes ont fait l’objet d’une évaluation anthropométrique, d’une visite médicale et d’un prélèvement sanguin.

Résultats: Le profil de facteur de risque pour les maladies chroniques liées au style de vie a révélé que l’hypertension et la sédentarité déclarées étaient classées comme le facteur de risque le plus important pour les groupes ruraux et urbains respectivement. Le profil de facteur de risque cumulatif indiquait que 40.1% de la population rurale étudiée et 34.4% de la population urbaine étudiée couraient le risque de souffrir de maladies chroniques liées au style de vie. De plus, 52.2% des participants vivant en zone rurale et 39.7% des participants vivant en zone urbaine présentaient trois facteurs de risque de syndrome métabolique ou plus.

Chronic diseases of lifestyle share similar modifiable risk factors, which include hypertension, tobacco smoking, diabetes, obesity, hyperlipidaemia and physical inactivity. In South Africa the burden for chronic diseases of lifestyle is high. A comparative risk-assessment study conducted in South Africa in which deaths attributing to selected risk factors were ranked by Norman et al.,³ showed that high blood pressure was ranked second, tobacco smoking third, alcohol harm fourth, high body mass index (BMI) fifth, high cholesterol seventh, diabetes eighth and physical inactivity ninth.

Metabolic syndrome refers to the cluster of risk factors that increases the risk of developing type 2 diabetes mellitus (DM) and cardiovascular diseases. Risk factors associated with metabolic syndrome include an increased waist circumference, elevated triglycerides, reduced high density lipid-C (HDL-C), high blood pressure and elevated fasting blood glucose. Various criteria for the diagnosis of metabolic syndrome exist. In a recent attempt, the International Diabetes Federation (IDF) and American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) proposed the presence of three or more of the following risk factors for the clinical diagnosis of metabolic syndrome:⁴

• increased waist circumference (population- and country-specific definitions)
• elevated triglycerides ≥ 150 mg/dL (1.7 mmol/L)
• reduced HDL-C < 40 mg/dL (1.0 mmol/L) in men, or reduced HDL-C < 50 mg/dL (1.3 mmol/L) in women
• elevated blood pressure (systolic ≥ 130 mmHg and/or diastolic ≥ 85 mmHg) or antihypertensive drug treatment in a patient with a history of hypertension is an alternate indicator
• elevated fasting glucose ≥ 100 mg/dL (5.6 mmol/L).

High cholesterol remains an important cardiovascular risk factor in all population groups in South Africa.⁵ In a study conducted to determine the impact of chronic diseases of lifestyle and related risk factors on mortality in South Africa, hypercholesterolaemia and raised low-density lipoprotein cholesterol, indicated an increased risk for ischaemic heart disease.⁶

Due to a more sedentary lifestyle, the prevalence of metabolic syndrome and chronic diseases is increasing worldwide. A world health survey conducted by the World Health Organization (WHO) in 2003, which investigated the physical activity levels of adult South Africans, found that less than one-third of South Africans met the American College of Sport Medicine and Centres for Disease Control and Prevention (CDC) recommendation for health-enhancing physical activity. Forty-six per cent of all South African adults were reported to be inactive (< 600 metabolic equivalent value minutes per week [MET min/wk]).⁷ National data on physical activity indicate that 53.5% of South African adults in the Free State province have an inactive lifestyle (< 600 MET min/wk). The low levels of physical activity were more prevalent in urban than rural settings.⁸

A clear and well-documented association exists between obesity and hypertension. Obesity is not only associated with an increased risk of developing hypertension, but also has an increased risk of developing other non-communicable diseases, such as coronary heart disease, diabetes and stroke. The WHO estimates that by 2015, the number of overweight people worldwide will increase to 2.3 billion, whilst more than 700 million will be obese.⁹ The South African Demographic and Health Survey (SADHS) conducted in 2003 amongst men and women aged 15 years and above, indicated that 55% of women and 30% of men were overweight (BMI 25 kg/m² – 29.9 kg/m²) or obese (BMI ≥ 30 kg/m²). Being overweight was reported in 13.5% and 23.3% of Free State men and women, respectively, whilst obesity was reported in 8.6% and 26.2% Free State men and women, respectively. Three per cent of men in the Free State had a waist circumference ≥ 102 cm, and 31.4% of women in the province had a waist circumference ≥ 88 cm.⁸

High blood pressure remains the most important risk factor for stroke.⁴ Strokes accounted for about one in every sixteen deaths in the United States of America (USA) in 2004.¹⁰ SADHS (2003) data acquired in 2003, indicated self-reported hypertension to be 13.3% and 26.6% amongst Free State men and women, respectively, a significant increase of 20% for women in the province since 1998.^8,11 In a South African study conducted by Conner et al. in 2005,¹² the overall hypertension prevalence rate in a study population of 9731 people in the age group 30 years and older, was 55%. The overall hypertension prevalence rate in Black African and Coloured people was 59% and 55%, respectively. In this study, hypertension was defined as a current blood pressure ≥ 140/90 mmHg, or having a history of hypertension.¹²

Information from the CDC Health Effects of Cigarette Smoking Fact Sheet, published in 2004, indicated that cigarette smoking approximately doubles a person’s risk for stroke. According to the 2011 WHO report on global tobacco use, tobacco smoking contributes to nearly 6 million deaths worldwide each year, with low and middle-income countries more at risk.¹³ A study conducted by Groenewald et al. in 2000 showed that tobacco smoking in South Africa accounted for 12% to 15% of deaths in adults over the age of 35 years.¹⁴ The 2003 SADHS indicated that smoking prevalence has declined in men (42% in 1998 compared to 35% in 2003), but significally not in women (11% in 1998 compared with 10% in 2003) in South Africa. The 2003 survey reported that the prevalence of current daily tobacco smoking amongst men in the Free State was 34.2%, whilst 6.7% of women in the province were smokers at that time.⁸

The WHO has projected the increase in people with diabetes to be 366 million by 2030, of which 298 million will be in developing countries.¹⁵ In a 2003 survey in the Free State province, the prevalence of self-reported diabetes amongst men and women was 1.8% and 4.0%, respectively.⁸

Anthropometric evaluation was done on adult participants, whose weight and height were measured after an overnight fast, in an examination gown and without shoes. A Seca^® (Germany) digital electronic foot scale was used for weight readings. The anthropometric indices computed were as follows: BMI as weight in kilograms divided by height in meters squared (kg/m²), where underweight was defined as BMI < 18.5 kg/m², overweight (pre-obese) as BMI 25–29.9 kg/m² and obese as BMI ≥ 30 kg/m².¹⁶ The cut-off point for central obesity was a waist circumference of 94-101 cm (increased risk) and ≥ 102 cm (still higher risk) for men and 80–87 cm (increased risk) and ≥ 88 cm (still higher risk) for women.^4,17

Participants underwent a medical examination as well as blood sampling. Blood specimens for the measurement of fasting venous plasma glucose (FVPG) were drawn into fluoride tubes. Samples were centrifuged within four hours and FVPG was measured immediately using the glucose oxidase method, on a Beckman LX20^® auto-analyser (Beckman Coulter, Fullerton, CA). Serum triglyceride levels (normal value: fasting < 150 mg/dL [1.70 mmol/L]) and total cholesterol (normal value: fasting < 200 mg/dL [5.18 mmol/L)], and high density lipoprotein (HDL) (normal levels for women: > 40 mg/dL [1.04 mmol/L]) were measured on fasting blood samples using enzymatic assay kits on a Beckman LX20^® auto-analyser (Beckman Coulter, Fullerton, CA). Low density lipoprotein (LDL) cholesterol levels (normal value < 100 mg/dL [2.59 mmol/L]) were calculated indirectly with the Friedewald equation, namely ([LDL-cholesterol] = [total cholesterol] − [HDL-cholesterol] − [triglyceride]/5).¹⁸

Blood pressure was measured in the supine position with a DS-175, auto-inflate electronic blood pressure monitor. Hypertension was defined as a systolic blood pressure of 140 mmHg or higher and/or a diastolic pressure of 90 mmHg or higher.¹⁹

During the process of completion of the individual physical activity questionnaires in interviews with each of the participants, they were asked to recall all physical activities they had performed during the previous day. Frequency of activities that were not undertaken everyday (e.g. gardening) was also determined. Using this information, the researchers calculated the physical activity level (PAL) for each participant. These levels were classified as follows:²⁰

• sedentary 1–1.39 PAL
• low activity 1.4–1.59 PAL
• active 1.6–1.89 PAL
• very active 1.9–2.5 PAL.

A total of 62 (11.1%) of the rural participants indicated in the health questionnaire that they had been diagnosed with diabetes before (see Table 1). Forty-four (71.0%) of these participants indicated that they used oral medication and two (3.2%) participants used insulin to control their diabetes. With regard to the urban participants, a total of 33 (8.1%) indicated in the health questionnaire that they have been diagnosed with diabetes before (see Table 1), of whom 14 (42.4%) used oral medication to control their diabetes. None of the urban participants indicated the use of insulin as diabetic treatment.

Complete data sets (health questionnaire and fasting blood glucose levels) for 43 of the rural and 11 urban participants on diabetes treatment were available. Elevated blood glucose levels of these participants are summarised in Table 5. Twenty-six (60.5%) rural participants and eight (72.7%) urban participants, who were taking medication to control their diabetes, had blood glucose levels ≥ 7.0 mmol/L.

By obtaining data from individual health questionnaires, anthropometric measurements and results from medical examination and blood sampling, multiple risk factors for chronic diseases of lifestyle could be identified in these two study populations. Tables 7a and 7b show the identified risk-factor profile for the two study populations. Self-reported data (high blood pressure, tobacco smoking, physical inactivity, diabetes), anthropometric data (high BMI, increased waist circumference measurements) and fasting blood cholesterol results, were used to rank the risk factors identified. The highest ranked risk factor in the rural community was self-reported hypertension followed by high BMI, whilst reported physical inactivity was the highest ranked risk factor facing the urban community, also followed by high BMI.

In this study, complete data sets for the following risk factors for chronic diseases of lifestyle were available in 474 rural and 378 urban participants:

• anthropometric data (high BMI)
• total cholesterol
• self-reported information regarding physical inactivity, high blood pressure, tobacco smoking and diabetes.

Table 8 illustrates the cumulative risk effects for these identified risk factors in the two populations. One person in the rural study population had all 6 risk factors.

The IDF and AHA/NHLBI criteria⁴ for the clinical diagnosis of the metabolic syndrome was used in this study. These criteria propose that the presence of any three of the following five risk factors constitutes a diagnosis of metabolic syndrome, namely:⁴

1. waist circumference (population- and country specific definitions)

2. triglycerides ≥ 150 mg/dL

3. HDL-C < 40 mg/dL (male) and < 50 mg/dL (female)

4. elevated blood pressure systolic ≥ 130 mmHg and/or diastolic ≥ 85 mmHg (anti-hypertensive drug treatment in a patient with a history of hypertension was an alternate indicator)

5. fasting blood glucose ≥ 110 mg/dL (≥ 5.6 mmol/L).

In both communities, the highest risk factor was HDL-C, followed by central obesity, self-reported treatment of previously diagnosed hypertension, elevated triglycerides and fasting blood glucose levels. The risk factor profiles for the rural and urban populations are shown in Tables 9a and 9b, respectively.

Using the criteria stipulated in Tables 9a and 9b, the number of risk factors for metabolic syndrome in participants in these two study populations was calculated, and is summarised in Table 10.

Previous studies carried out in South Africa have shown that high blood pressure contributes to a considerable burden of cardiovascular disease.^8,23,24 In a study on confirmed lifestyle-related chronic diseases, the South African Centre for Health Systems Research and Development stated that hypertension (41%) was the condition most commonly reported, followed by diabetes (14%).²⁵ Our study revealed that the prevalence of self-reported hypertension was 62.6% in the rural and 48.3% in the urban community. The higher prevalence in the rural community can possibly be due to the older mean age of the rural participants. The prevalence of self-reported diabetes mellitus was 11.1% in the rural and 8.1% in the urban study populations. It was also found that the control of hypertension and diabetes in these communities was problematic. Despite being on treatment for hypertension, 78.3% (227/290) of rural participants presented with increased blood pressure, which was also observed amongst 66.4% (75/113) of urban participants on antihypertensive therapy. These findings were clearly indicative of poor control of hypertension, which was one of the main reasons for referral after medical examination in the rural community. Although some patients were receiving treatment for diabetes mellitus, results from blood glucose levels nevertheless indicated elevated fasting blood glucose levels in both rural and urban patients (see Table 5).

Another risk factor for chronic lifestyle diseases that was found to be a major problem, especially in the female population, was obesity. In our rural study population, 57.6% of women were found to have a waist circumference measurement of ≥ 88 cm and 43.1% a BMI ≥ 30 kg/m², whilst in the urban study group, these measurements were obtained in 48.6% and 41.0% of women, respectively. An earlier study by Walker²⁶ revealed the prevalence of obesity (BMI ≥ 30 kg/m²) to be in the order of 59% amongst urban Black women.

Physical inactivity and consequential high BMI were the top-ranked risk factors for chronic lifestyle diseases facing the urban study population. This observation is supported by the findings of the SADHS in 2003, namely that low levels of physical activity were higher in urban than in rural settings.⁸ The markedly higher self-reported physical inactivity levels (66.5% urban vs. 27.3% rural) could be attributed to the more sedentary lifestyle in urban communities due to the availability of public transport and less physically active occupations in urban areas.

Limited information available on the premature mortality rate due to chronic lifestyle diseases in different socio-economic areas in South Africa, indicates a 39% and 33% premature mortality in rich and poor districts, respectively.²⁷ Our study illustrates the presence of major risk factors for chronic diseases of lifestyle in both study populations and identified hypertension (self-reported), as well as overweight and obesity, as major threats in the rural community and physical inactivity (self-reported), and overweight and obesity the major threats in the urban community (see Tables 7a and Table 7b). Forty per cent of the rural study population had a higher cumulative risk for 3 or more risk factors for chronic lifestyle diseases.

Identifiable risk factors for metabolic syndrome, for example, increased waist circumference, raised blood pressure or a history of hypertension treatment, elevated fasting blood glucose, high triglycerides and low HDL amongst this population, are summarised in Tables 9a and 9b using IDF and AHA/NHLBI criteria.⁴ Reduced HCL-C levels was the most common metabolic risk factor (60.9% of the rural and 61% of the urban population), whilst elevated fasting blood glucose was identified as the least prevalent (22.6% rural and 14.1% urban). Female participants revealed higher risk for different risk factors for metabolic syndrome. A higher prevalence for all the risk factors except elevated HDL-C was observed in the rural community. The study revealed that 52.2% of rural and 39.7% of urban participants were identified with three or more risk factors for metabolic syndrome.

This study highlights the need for serious recognition of the increasing burden of lifestyle diseases and metabolic syndrome in rural and urban populations in South Africa. The escalating healthcare cost associated with the risk profiles indicated in this study, presents a specific challenge to healthcare providers, researchers, government officials and the general population. Once risk factors have been identified, lifestyle intervention programmes can improve the overall health profile of the communities. Intervention programmes, for example dietary programmes that encourage better control of existing diseases such as hypertension, diabetes and dyslipidaemia, can form the cornerstones of a healthier community. Physical activity programmes (e.g. community fitness programs) can facilitate weight control and promote overall physical health. Patients with a specific risk profile, for example, where metabolic syndrome has been identified, will benefit significantly from intensive dietary and exercise programmes to improve blood glucose levels, lipid profiles, waist circumference and lower blood pressure.^28,29 The development and implementation of relevant health-promoting and -intervention strategies that are cost-effective and culturally sensitive, with the aim to improve the general health and reduce the risk for chronic diseases of lifestyle and metabolic syndrome in these populations, are therefore urgently advised.

Based on the findings of this survey, we recommend specific strategies targeting these known risks that could substantially impact on the disease profile of these communities. These strategies included the following:

1. the introduction of education and awareness programmes that focus on the current emerging trend of chronic diseases of lifestyle and metabolic syndrome in these communities

2. efficient and targeted lifestyle intervention programmes that focus on intensive dietary and exercise programmes to reduce the risk factors identified by this investigation

3. the poor control of hypertension and diabetes clearly indicates the need for optimally accessible primary healthcare provided by community health centres

4. the need for Faculties of Health Sciences in South Africa to implement community relevant health professional training programmes

5. further research to indicate which combinations of the metabolic syndrome criteria best predict cardiovascular risk in these communities

6. follow-up studies to investigate the impact of implemented lifestyle intervention programmes in these rural communities.

The National Research Foundation (NRF) is acknowledged for financial support. Dr Daleen Struwig, medical writer, Faculty of Health Sciences at the University of the Free State, is acknowledged for technical and editorial preparation of the manuscript.

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