Falling blood pressure not down to drugs, say experts

Blood pressure lowering drugs were not responsible for the population decline in blood pressure seen in many countries during the 1980s and 1990s, concludes a study published online by the BMJ today.

High blood pressure is a key risk factor for coronary heart disease. It is declining in many industrialised countries, but the mechanism is not known.

Doctors use two methods to reduce blood pressure. ‘High risk’ interventions target individuals with the highest readings, usually with antihypertensive drugs, lowering blood pressure selectively. By contrast, ‘mass population’ interventions target everybody (through dietary, lifestyle, or environmental factors) and tend to cause similar falls in low, middle and high readings. Both methods change the population mean value.

So did blood pressure fall due to better medication or was it pushed by a general trend towards healthier lifestyles?

To answer this question, researchers analysed patterns of blood pressure decline by pooling the results of a large trial conducted across 38 populations in 21 countries from the mid-1980s to mid-1990s.

Blood pressure fell across all 38 populations at all levels of readings.

This suggests that antihypertensive medication made no detectable contribution to population decline in blood pressure in the mid-1980s to mid-1990s, say the authors.

They believe that other determinants of blood pressure decline must have been more pervasive and powerful in the population as a whole during that decade, although they are unable to say what caused this.

These findings do not deny the importance of antihypertensive medication in the individual, but are important in understanding blood pressure as a challenge to public health, they conclude.

Professor Tunstall-Pedoe, emeritus professor at the University of Dundee said today:

"I am pleased to be working with colleagues nationally and internationally on these questions although officially retired. This paper asked a basic question. The answer challenges a common fallacy that blood pressure is simply a medical problem-it shows there is more to health than popping pills. We found it was not popular with three international medical journals we approached first, so it is good to see it published in the BMJ. It was based on data from the 21-nation collaboration of the World Health Organization MONICA* project, which I helped to start 25 years ago and to manage since then. Maybe MONICA has more surprises to come."