Pouring salt on the wound this World Hypertension Day

May 17 was “World Hypertension Day”. But you don’t have hypertension. You don’t take drugs to lower your blood pressure. So you don’t have anything to worry about - or do you?

Alongside smoking, high blood pressure is the leading cause of death and disability in Australia. While one of the most widely recognised risks to health, it is also one of the most poorly understood - both by those suffering the consequences and those trying to prevent them.

Even if you haven’t been diagnosed as hypertensive you shouldn’t be resting on your laurels. And neither should our government.

Among doctors and patients alike, blood pressure is seen as a problem only when it breaches a certain threshold (140 “over” 90 mmHg - millimetres of mercury) and is diagnosed as “hypertension”. Your health risk actually starts to rise long before that.
To understand the difference between hypertension and high blood pressure is to appreciate the huge burden of ill health caused by elevated blood pressure levels that don’t reach the hypertension cut point. While individuals with very high levels of blood pressure are at particularly elevated risk, it is the masses with moderate elevations that suffer most of the consequences.

The upshot is that half of all death and disability caused by high blood pressure actually occurs in people without hypertension. These are people who will never be part of a hypertension control program and who are consigned to their fate by the obsolete “hypertension” paradigm.

Even for those that do have hypertension, and are on the radar, the current approach addresses only a small part of the problem. Less than a half are diagnosed and treated, less than a quarter reach their blood pressure goal and almost none have their blood pressure returned to optimal levels.

To add insult to injury, the clinical hypertension control program does not come cheap. At more than a billion dollars a year the government and the public might reasonably expect significant health gains. While they certainly get some, the question is whether they might do better.

The answer to this question is an emphatic “yes”. The consequences of confusing “hypertension” with “high blood pressure” are profound - the harm is hugely underestimated, the causes remain mostly unaddressed and the response is ineffective and inefficient. But the corollary is also true - getting the approach right has much to offer.

This year’s focus on salt is welcome. Salt reduction efforts do not differentiate between the hypertensive and the non-hypertensive, and the potential for health gains are enormous.

Blood pressure in healthy young adults is about 100/60mmHg. In the absence of a Westernised diet and lifestyle it would remain at that level throughout life. In practice, the average Australian can expect a blood pressure some 50 per cent higher by the time they reach old age. Salt is the single main reason for this.

Humans need 1-2 grams of salt a day against a current Australian average of 8-10 grams. The glut of salt in our diet comes courtesy of our food manufacturing, retailing and catering industries. Tens of thousands of tons of salt are added to the food supply each year accounting for three quarters of the salt we eat.

Salt reduction will not be achieved by clinical interventions or personal choice. The key is for industry to add progressively less salt to the food supply. Small annual reductions in salt content will be imperceptible to consumers and can be incorporated into ongoing product reformulation. A few Australian companies are starting on this path but its time for government to force the issue.