Tobacco Info

From Tobacco Info No. 5 - April 2011
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Research update by the Ontario Tobacco Research Unit

The Ontario Tobacco Research Unit (OTRU) is a research network that is recognized as a Canadian leader in tobacco control research, monitoring and evaluation, teaching and training and as a respected source of science-based information on tobacco control. In each issue of Tobacco Info, OTRU presents a review of the latest ground breaking tobacco studies around the world. For more information, visit www.otru.org.

Cessation

Campling and colleagues in the Journal of Thoracic Oncology investigated the rate of spontaneous smoking cessation among smokers in the years prior to being diagnosed with lung cancer.  They found that 48% of lung cancer patients at a medical centre in Philadelphia had quit smoking on average 2.7 years before being diagnosed with cancer. Despite the high levels of nicotine addiction, many of those who quit did so with little difficulty. The authors speculate that spontaneous quitting may be a presenting symptom of lung cancer.

In the International Journal of Environmental Research and Public Health, Fix et al. report findings from the population-based International Tobacco Control Four Country Survey demonstrating the increase in use of varenicline in the United States, Canada, the United Kingdom and Australia since the drug came on the market.  In all countries, varenicline became the second most popular stop smoking medication behind nicotine replacement therapy (NRT). 

A review of the safety and efficacy of NRT among pregnant women published in Addiction found insufficient evidence to conclude whether or not NRT was safe or effective in this population.  Coleman and colleagues systematically searched the literature for randomized controlled trials examining NRT use during pregnancy. Pooling the studies found a modest and no significant effect of NRT, particularly among studies that used placebos. 

Le Strat and other researchers at the Centre for Addiction and Mental Health warned that the populations recruited for inclusion in clinical trials for cessation were significantly different than the populations of adult smoking in the US.  According to typical criteria, nearly two-thirds of the smoking population would be ineligible to participate in most clinical trials. Restricting trials to those smoking 10 cigarettes per day or less and those who lacked motivation to quit excluded the greatest percentage of individuals (32% and 17.6%, respectively).

On the other hand, Khara and Okoli analyzed data from an intensive tobacco-dependence treatment program for addiction services and found that those in drug treatment successfully quit smoking at rates similar to the general population. The study, published in the American Journal on Addictions, found a successful abstinence rate of 43% among 202 participants in this high risk population.  

In the American Journal of Medicine, Mills and colleagues conducted a systematic review of all randomized trials and observational studies examining the effects of cessation on post operative complications.  The pooled analysis found that quitting smoking reduced the risk of complications by 41% and that each week of cessation reduced the risk by 19%. 

Cigarette packaging and advertising

David Hammond of the University of Waterloo reviewed the evidence for plain packaging of cigarettes in Salud Publica de Mexico.  He found that plain packaging increases the effectiveness of health warnings, reduces false health beliefs about cigarettes and reduces brand appeal especially among youth and young adults.

Other substance use

In the Journal of American College Health, Arbour-Nicitopoulos and co-authors surveyed drug use among 1,207 University of Toronto students.  Students who perceived higher rates of use among their peers were more likely to smoke. Overall, participants were thought that the typical student had used alcohol, cigarettes and marijuana but that actual rates of use were low in comparison with populations in other setting (65% used alcohol, 13.5% marijuana and 13.5% cigarettes). 

In Drug and Alcohol Dependence, Lopez-Quintero and co-authors examine the predictors of first use and transition to dependence on nicotine, alcohol, cannabis and cocaine. Using the National Epidemiologic Survey on Alcohol and Related Conditions, the study found that nicotine users were most likely to transition to dependence but the rate of transition was slower than for those who became dependent on cannabis or cocaine.

Han et al. in Neureport test a common mechanism for the effects of cannabis and nicotine on the brain.  They suggest that counteractive effects of cannabinoid and nicotine-addictive behaviour through opposite changes in brain chemistry. Co-administration leads to a blockade of facilitated long term depression and long term potentiating induction in these neurons and elimination of conditioned place preference.

Aboriginal peoples

A population based study of a Canadian Aboriginal community found that those who smoked and carried a specific gene polymorphism (HNF1A G319S) were nearly seven times more likely to develop diabetes.  Ley and colleagues, in a study published in BMC Medical Genetics, examined 606 participants over a 10 year period and found that smoking amplified the disease risk of developing diabetes.  Carriers of the gene who did not smoke were at no increased risk compared to non carriers after controlling for other diabetes risk factors.  

Muckle et al. in an article published in Alcoholism: Clinical and Experimental Research examined alcohol and tobacco use during pregnancy. They interviewed 208 Inuit women from Arctic Quebec during pregnancy and post partum and found that 92% of the women smoked. Smoking was associated with heavy levels of binge drinking and illicit substance use.

By Michael Chaiton