Listener: 24 September, 2005.
Although we think of lung cancer as the disease of tobacco, the weed is associated with other cancers, with respiratory disease (such as emphysema), and with heart and circulation conditions (cardiovascular disease). Not only do the chemicals in tobacco smoke trigger mutations within cells that lead to cancer, and damage the lungs, but they also stiffen the walls of the blood vessels. That requires the heart to work harder, so smokers are more prone to coronary heart disease (CHD) and stroke. Stopping smoking is the best way of preventing heart disease.
So it is not so surprising that New Zealand’s anti-tobacco campaign was led by cardiologist Sir David Hay, of Christ-church, who has just published his memoirs, Heart Sounds. Hay became a cardiac physician in the 1950s, when the eminent British epidemiologist Sir Richard Doll, who died a few months ago, began reporting his ground-breaking work, which showed that smoking causes early mortality. Hay returned from his British training in 1955 convinced that New Zealanders had to quit smoking. As the first medical director of the New Zealand Heart Foundation, he had a leading role in the campaign.
It makes good sense for a heart doctor to recommend smoking cessation. Cancer physicians welcome quitting, too, but the mutation that triggers the cancer or the undermining of the lung may be not reversible, although cessation stops further mutations and damage. The news from cardiologists is even more heartening.
Within a year of quitting, the excess risk of CHD caused by smoking is reduced to about half. It continues to decline gradually. After 15 years of abstinence, the risk of CHD is similar to that of persons who have never smoked. The risk of stroke for ex-smokers takes five to 15 years to return to that of never-smokers. (The current state of knowledge is summarised in a recent National Heart Foundation technical paper authored by Dr Hay, although he is officially long-retired.)
It is a standard joke that your GP will advise you to stop smoking, even if a cigarette has never passed your lips. Breathing in other people’s cigarette smoke also raises disease risks. One study found that nurses regularly exposed to second-hand smoke at work were almost twice as likely as the unexposed to suffer heart disease.
The shift in attitudes to smoking has been brought about by the efforts of many people. GPs discouraged their patients from smoking. Public health physician Murray Laugesen at the Ministry of Health, oncologist Alan Gray first medical director of the Cancer Society, and university epidemiologist Robert Beaglehole played vital roles. So have numerous lay-people, particularly Deirdre Kent, first director of ASH (Action on Smoking and Health), which Hay helped found. Their concern and passion enabled politicians to institute measures to reduce smoking (including raising excise duties on tobacco). The anti-smoking campaign is probably the single most important health measure taken in the past 30 years.
Hay’s genial book throws light on medicine over the past 50 years, with frequent apologies for past practices that would be unacceptable today; there have been improvements in how we treat patients.
The reflection is more strident in the penultimate chapter’s “personal prescriptions”, when the autobiographer becomes the passionate physician giving firm advice on how to look after one’s heart. The gentle humour remains, as Hay starts by confessing that he, too, has trouble with his weight. (He experimentally smoked as a teenager, but never as an adult.) For the chapter is about changing diet, increasing exercise, and that damned controlling of weight, as well as not smoking. Hay was also a pioneer in the promotion of behaviour change. Much of what he suggested is today’s conventional wisdom – his advocacy helped make it so.
This leads to the economic problem of the ageing population, as greater longevity imposes a heavier burden on the economy. However, we all benefit if loved ones survive longer because of taking David Hay’s advice, so that is a challenge economists can live with.