Issue 44 / 21 November 2011

HEALTH experts have called for better education of health care providers and the public about the link between illicit drug use and stroke following new research showing risk factors for ischaemic stroke in young people.

The study, published in the MJA, identified obesity and misuse of illicit drugs, in particular marijuana, among the stroke risk factors. (1)

Of the 326 patients aged between 15 and 50 years who had been admitted to a public hospital in Adelaide with a primary diagnosis of ischaemic stroke, 92 (28%) were obese and 51 (16%) had misused illicit drugs — mostly marijuana and amphetamines.

The most frequent stroke risk factors identified by the study were dyslipidaemia (57%), smoking (49%) and hypertension (32%), which tallied with other studies.

However, some of the risk factors, aetiologies and features of ischaemic stroke among young people in the Australian study differed significantly from published data for young patients around the world.

“Patients in Adelaide are more likely to be obese, to be misusing marijuana and amphetamines, to suffer a cardioembolic event and to have a stroke that concurrently affects both the anterior and posterior cerebral circulation”, the authors wrote.

The authors said that evidence supporting marijuana as a stroke risk factor was increasing. Of the illicit drug users in the study, 71% used marijuana.

“Recent studies have shown marijuana users to have increased levels of apolipoprotein C-III, a known cardiovascular risk factor, as well as an adjusted odds ratio of 1.76 for ischaemic stroke”, they wrote.

Associate Professor David Blacker, a neurologist and stroke physician at Sir Charles Gairdner Hospital in Perth, agreed with the study authors that the findings highlighted the need to educate health care providers as well as the public about the link between drug use and stroke.

Dr Blacker said although other studies had indicated marijuana may have an effect on the blood vessel wall, until now there had been little direct evidence of a link with stroke.

The finding that excess weight was a risk factor for stroke even in younger people was concerning given the obesity epidemic, he said.

“The message is that stroke can happen in people under 50. If you let yourself get overweight, or you use drugs, this is a consequence.”

Amphetamine use also emerged as a stroke risk factor. The authors found that of the illicit drug users studied, 37% used amphetamines, mostly intravenously.

Amphetamines increase the risk of stroke by several mechanisms, including elevation of blood pressure, vasculitis and cerebral vasospasm.

And it seems more people may be placing themselves at risk of having an early stroke. Almost one in 10 Australian men aged under 30 years were estimated, at some time in their lives, to have had a stimulant use disorder, which means they had misused or had been dependent on stimulants, according to another study published in the same issue of the MJA. (2)

An MJA editorial, coauthored by Dr Dan Lubman, director of the Turning Point Alcohol and Drug Centre at Monash University, said that other elements compound the risk of cerebrovascular incidents in drug users, such as tobacco smoking and the risk of infectious endocarditis due to intravenous use. (3)

“Given that stimulant users commonly seek help from general practitioners for a range of health issues, offering a safe environment to talk about drugs, where confidentiality is assured and patients do not feel judged, is a critical first step in identifying harmful use”, the editorial said.

“This can be done in a non-confronting way by discussing how stimulant use (both legal and illicit) might be a factor in the aetiology of certain conditions.”

– Amanda Bryan

1. MJA 2011; 195: 610-614
2. MJA 2011; 195: 607-609
3. MJA 2011; 195: 565-566

Posted 21 November 2011

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