IT seems that smokers with different genetic make-ups may benefit from different treatments.
That’s the summary of a paper published in The Lancet Respiratory Medicine earlier this month, which drew on existing knowledge that smokers can be broadly categorised into normal metabolisers of nicotine and slow metabolisers of nicotine.
Those differential rates of nicotine metabolism are genetically based. The multicentre randomised controlled trial found that varenicline had higher efficacy in normal metabolisers and nicotine patches had higher efficacy in slow metabolisers.
This is interesting because it may help clinicians who use pharmacology to help patients quit smoking to prescribe the most appropriate treatment.
But it also highlights broader issues in medicine, with smoking among people with mental illness a good example.
It was in the 1970s that efforts to encourage smokers to quit really got going. Smoking rates dropped in many developed countries due to discouragement of smoking through advertising restrictions and education campaigns, and later restrictions on smoking in public places and deliberate denormalisation.
At the same time, a few people started looking at marginalised groups like people with mental illness. They noticed that smoking rates were much higher than average in these groups, and a number of physiological hypotheses were developed.
People with schizophrenia were said to self-medicate with nicotine, to have different genetics, to metabolise monoamine oxidase differently, and so on.
In the two decades from 1990, hundreds of papers examined why people with mental illness smoked, but very few stood back and looked beyond the molecular level.
It was an odd approach. When smoking rates quadrupled from 1900 to 1950 nobody thought this was because of changes in genetics or biochemistry. However, sociological explanations for excessive smoking among people with mental illness had simply not been considered.
It’s only in the past 10 years that the lives of people with mental illness, rather than their brain biochemistry, became the focus in research about their smoking rates. It has been discovered that, broadly speaking, people with mental illness had not been offered the same advice and support about quitting as others. They were willing to quit, they were able to quit, but health professionals had not taken the trouble to ask about smoking and advise about quitting.
Indigenous Australians have much higher rates of smoking, as we all know. But what is not often realised is that these rates are declining, from 51% in 2002 to 45% in 2008, and then to 41% in 2012–2013. And they are declining not because the physiology of Indigenous Australians has changed, but because efforts are being made to offer a similar approach to smoking — denormalise it, advise quitting and offer help to those who want it.
The rate of smoking in prisoners is still very high, with cigarettes being widely available in prisons and, to some extent, used as currency. Getting smoking out of prisons is highly controversial, with reports of attacks on prison guards doubling since the Queensland Government banned smoking in all jail areas in May last year. Some see smoking bans as an abuse of human rights (although a right to smoke has never been established by any reputable body), while others wonder about the practicalities and caring for quitting prisoners who, right now, are short on health care.
While debate goes on, more and more people, already highly disadvantaged, have smoking added to their burden.
The point of all this? The Lancet Respiratory Medicine paper is interesting, but if a clinician had to choose between deciding to use the right pharmacological agent and deciding to offer every patient who smokes help to quit, the latter approach would have far greater benefit.
There’s plenty we don’t know in health. But there’s also plenty we do know that’s not applied.
A shift in focus – from always trying to learn more to applying what we know to more people – would lead to greater gains in health.
Dr Mark Ragg is an adjunct senior lecturer in the Sydney School of Public Health, University of Sydney.
Jane McCredie is on leave.