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.

In 2006 the UK government negotiated with industry voluntary targets for the concentration of salt in processed foods. Sector-wide salt reduction has been achieved and average population salt consumption has come down by 10 per cent. This has already prevented thousands of premature deaths and many more non-fatal strokes and heart attacks.

The really good news is that this can come cheap. A national salt reduction program for Australia could be delivered for about 1 per cent of the annual cost of the existing clinical hypertension program. Furthermore, getting industry to take salt out of foods could produce the same health benefits as the clinical hypertension program within just a few years of implementation.

The real question is whether government will take on industry. Clinical hypertension control programs are just one more costly clinical thumb in a dyke holding back a flood of lifestyle diseases.

Salt reduction programs were recently highlighted as having greater potential for disease prevention than smoking cessation programs. The control of blood pressure through salt reduction represents probably the single best opportunity for the prevention of death and disability in Australia. A few simple, easily implemented measures could avert thousands of deaths, heart attacks and strokes within just a few years.