Managing Pre-Hypertension - Reducing a Global Burden or Preventing a Global Catastrophe?

What is 'pre-hypertension'? Is it a problem and if so what if anything can we do about it? Given the changing definitions of hypertension I will not get tied down by further arbitrary cut off points - but suffice to say that as blood pressures track with age, those with pressures above the median of pressures in childhood or early adult life have a high risk of having pressures over 140 systolic or 90 diastolic by middle life and a 50% or more chance of being hypertensive should they survive to 70 years. However that is just the beginning of the problem. These estimates are based on figures from the affluent nations in the 1980's from which extrapolations to 2020 predicted an increasing contribution of hypertension to the global burden of disease as infectious disease and malnutrition diminish in the developing world. These are probably gross under estimates as they failed to predict the rapid increase in rates of obesity worldwide with accompanying hypertension, diabetes and vascular disease. The effects of increasing hypertension on cardiovascular morbidity and mortality will be further exacerbated by continued high smoking rates in the developing world and increasing rates in young women. Decreasing physical activity and increasing use of junk foods with high saturated fat, sugar and salt are further increasing blood pressure levels both directly and via obesity. These lifestyle patterns have spread rapidly throughout all major continents and are reflected in epidemic-like rates of hypertension and diabetes in South East Asia, in some former Eastern Block nations and in economically disadvantaged indigenous populations such as those in North America and Australasia. For example, in the Monica study middle aged men in Poland had an alarming 57% prevalence rate for hypertension (140/90 or more) compared with 32% for US surveys, with hypertensives having twice the overall mortality rates of normotensives. Sedentary lifestyles and unhealthy eating patterns in the developed world have tripled rates of obesity and diabetes in young and middle aged adults in the last twenty years and will likely reverse the falling rates of heart attack and stroke.

Although advances in drugs have made life far more tolerable for hypertensives, over 75% of treated patients have inadequate blood pressure control. This is probably at least in part because by the time treatment is started there are already irreversible changes in large artery stiffness as a consequence of lifelong exposure to gradually increasing pressures. This is especially likely to be the case in isolated systolic hypertension where the problem is primarily one of reduced arterial compliance. Add to these observations the fact that in most communities less than half the hypertensives are receiving treatment gives little cause for complacency about current management practices.

We know the main lifestyle or environmental factors that can keep blood pressures normal and reverse pre- and mild hypertension. They include avoiding excess body fat, regular physical activity in day to day life, dietary patterns typified by the DASH study with several serves of fruit and vegetables, and substitution of saturated fat products with low fat dairy foods. When these habits are coupled with moderation of salt intake to around 5 g a day and avoidance of heavy alcohol consumption few will develop hypertension or diabetes.

How can we achieve these changes in the face of major cultural shifts world wide and globalisation of behavioural patterns based on urbanisation, cars, computers, television, fast food, jumbo size portions and high calorie soft drinks. It presents an enormous challenge and a call for action at many levels. If we just talk about it we will be no more effective than King Canute sitting on the seashore telling the tide to go back. Let's not mince words, we are talking about the need to prevent hypertension, obesity, diabetes and related cardiovascular disease from becoming a global health catastrophe. Action means putting nutrition and physical activity along with smoking as priorities for governments, national and international bodies, health professionals, public health personnel, the food industry, the media, town planners, schools, parents and the public at large. Efforts need to include a major focus on children and their families to encourage early lifelong healthier eating and activity and to prevent childhood obesity. Pre-hypertension is endemic. Hypertension and diabetes rates have already increased dramatically in the most heavily populated nations. The causes are obvious. The solutions are not. They will require resolve, concerted effort, ingenuity, education, substantial resources, not least to counter the advertising and legal budgets of the food and tobacco industries, legislation and above all both community and political will.

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