Risk factors for hypertension
Currently, the age-standardised prevalence of hypertension in South African adults older than 15 years of age is 35.1%.
Even in adolescents and young adults aged 15-25 years, the prevalence is as high as 1 in 10. In other words, everyone needs to have their blood pressure (BP) checked regularly.
Unhealthy lifestyle and eating habits play a major role in the development of high BP, according to Dr Krisela Steyn, MRC researcher and project leader of several studies about BP.
Genetic predisposition also plays an important role – if there’s a history of hypertension, diabetes or stroke in your family, early screening is advised.
Among South African adults with hypertension, 48.7% are unscreened and undiagnosed, 23.1% are screened but undiagnosed, 5.8% are diagnosed but untreated, 13.5% are treated but uncontrolled, and only 8.9% are controlled.
This means that 91.1% of hypertensive individuals are not controlled, which translates into a very significant unmet need in South Africa. There’s an urgent need to improve awareness, screening, and treatment. An estimated 53 men and 78 women die in South Africa each day from the impact of hypertension.
Black South Africans suffering from hypertension are at higher risk of developing cerebral bleeding, stroke, malignant hypertension, kidney disease and heart failure. According to studies by Wits University, hypertension is responsible for 33% of heart failure cases in the black population. Indian and white South Africans with hypertension are at higher risk of developing coronary artery disease, leading to heart attacks.
Individuals who stop taking their medication because of unpleasant side effects need to be aware of the consequences of uncontrolled BP. The good news is that, thanks to a wide variety of different BP treatments, most people can be treated correctly without experiencing unwanted side effects.
In 90-95% of cases, there’s no known cause of hypertension. However, there are factors that contribute to the problem. If you have two or more risk factors, your risk for hypertension can be classified as “high”.
Risk factors can be divided into three main categories:
1. Risk factors you cannot control. These include your parents (determining your ethnicity, your genes and therefore your family history) and your age.
2. Risk factors you can control. These include overweight, lack of exercise, smoking, wrong food choices, use of the contraceptive pill, use of anti-inflammatory drugs, and the use of certain recreational drugs.
3. Associated diseases or organ damage can also increase your total risk. These include high blood cholesterol levels, existing heart disease, angina, heart failure, diabetes, previous stroke (including so-called mini-strokes), kidney damage, damage to the retina of the eye, and damage to the blood vessels.
Risk factors and associated conditions create a double-edged sword. Some risk factors will not only increase your chances of developing high blood pressure (BP) but, as soon as you are indeed hypertensive, some associated factors will increase your risk of developing complications such as cardiovascular disease and kidney failure. This, in turn, can increase BP. A vicious cycle is the end result.
In summary, people with the following risk factors are at major risk of developing hypertension, followed by complications and organ damage due to high BP:
Increasing risk with age
Increase fresh fruit and vegetables. Reduce salt and saturated fat. Avoid refined carbohydrate (sugar).
Have no more than two standard drinks per day.
Diet and medication (statins)
Diet and medication
Higher risk in individuals of African descent
Parent, sibling or close relative with hypertension, diabetes, stroke or premature heart disease
BMI <25kg/m2 and waist circumference <102cm in males and 94cm in females
Do 30-45min brisk walking at least 4-5 times per week
Oral contraceptives, steroids, anti-inflammatory drugs, stimulants
Metamphetamine (tik), cocaine (may precipitate a hypertensive crisis)
Your doctor will take all your risk factors into account when compiling your individualised management plan.
These factors will influence decisions of when to start drug treatment, as well as the choice of medication. Special examinations and regular follow-up treatment will be needed to optimise your health.
Special note: Since hypertension often has no symptoms and may go undetected for years, all adults, even if feeling healthy, should be screened for high BP on an annual basis. Contrary to popular belief, high BP often occurs in younger people.
Healthcare professionals should therefore also routinely measure BP in this group, especially if the individual is overweight or obese, and if there’s a family history of hypertension.
How can hypertension be prevented?
Currently, the battle to prevent hypertension is being lost as there’s an ever-increasing prevalence in South Africa.
Prevention should start in childhood. If you’re a parent, you should restrict the consumption of fast foods and carbonated drinks, encourage more exercise (e.g. cycling to school and sports participation at school), restrict time spent in front of the television and playing computer games, and offer healthier mealtime choices for your children.
Unfortunately, this isn’t always practical given the pressures in the modern economy, the higher cost of healthy foods, the convenience of fast foods, and safety concerns (e.g. crime). There needs to be a greater focus at Government level to improve the situation.
The WHO Global Non-Communicable Disease Alliance Action Plan advocates the following voluntary global targets for country member states:
- 10% reduction in harmful use of alcohol.
- 10% reduction in insufficient physical activity.
- 30% reduction in mean population intake of salt.
- 30% reduction in current tobacco use.
Up to 80% of cardiovascular disease can be prevented through lifestyle measures. This includes maintaining a healthy weight, getting enough exercise, following a healthy diet, and avoiding tobacco.
In South Africa, the government has introduced legislation to slowly reduce salt in processed foods like bread. This has been successfully implemented in the UK with a population-based reduction in BP. Furthermore, a sugar tax is being mooted to encourage manufacturers to reduce sugar content in, for example, carbonated beverages.
Sports should also be reintroduced into all schools in South Africa, and education programmes in schools need to focus more on healthy lifestyle choices.
South Africa has, however, been very successful in limiting tobacco advertising and smoking in public areas, work places, restaurants and bars.
Reviewed by Prof Brian Rayner, nephrologist and Director of the Hypertension Clinic, Groote Schuur Hospital. MBChB, FCP, MMed, PhD. May 2018.