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Don’t Inhale; Mixed News on Tobacco and Pot

Thursday, January 12, 2012 // Uncategorized

 I was surprised by this article in the New York Times about a study on nicotine replacement therapy.  I never thought that these nicotine replacements led to long term smoking cessation, but I thought they were useful in certain patients in the short term.  This article seems to support that idea.

 Nicotine Gum and Skin Patch Face New Doubt

By
Published: January 9, 2012
        The

nicotine

       gum and patches that millions of smokers use to help kick their habit have no lasting benefit and may backfire in some cases, according to the most rigorous long-term study to date of so-called nicotine replacement therapy.

 

Chris Goodney/Bloomberg News

 

 

The study, published Monday in the journal Tobacco Control, included nearly 800 people trying to quit smoking over a period of several years, and is likely to inflame a long-running debate about the value of nicotine alternatives.

In medical studies, the products have proved effective, making it easier for people to quit, at least in the short term. Those earlier, more encouraging findings were the basis for federal guidelines that recommended the products for smoking cessation.

But in surveys, smokers who have used the over-the-counter products, either as part of a program or on their own, have reported little benefit. The new study followed one group of smokers to see whether nicotine replacement affected their odds of kicking the habit over time. It did not, even if they also received counseling with the nicotine replacement.

The market for nicotine replacement products has taken off in recent years, rising to more than $800 million annually in 2007 from $129 million in 1991. The products were approved for over-the-counter sale in 1997, and many state Medicaid programs cover at least one of them. 

“We were hoping for a very different story,” said Dr. Gregory N. Connolly, director of Harvard’s Center for Global Tobacco Control and a co-author of the study. “I ran a treatment program for years, and we invested” millions in treatment services.

Doctors who treat smokers said that the study findings were not unexpected, given the haphazard way many smokers used the products. “Patient compliance is a very big issue,” said Dr. Richard Hurt, director of the Nicotine Dependence Center at the Mayo Clinic, who was not involved in the study.

Dr. Hurt said products like nicotine gum and patches “are absolutely essential, but we use them in combinations and doses that match treatment to what the individual patient needs,” unlike smokers who are self-treating.

The products have been controversial since at least 2002, when researchers at the University of California, San Diego, reported from a large survey that they appeared to offer no benefit. The study did not follow people over time. A government-appointed panel that included nicotine replacement as part of federal guidelines for treatment also came under fire, because panel members had gotten payments from the product manufacturers.

“Some studies have questioned these treatments, but the bulk of clinical trials have unequivocally endorsed them,” said Dr. Michael Fiore, director of the University of Wisconsin’s Center for Tobacco Research and Intervention and the chairman of the panel that wrote the guidelines. Dr. Fiore, who has reported receiving payments from drug makers, said that “there are millions of smokers out there desperate to quit, and it would be a tragedy if they felt, because of one study, that this option is ineffective.”

In the new study, conducted in Massachusetts, the researchers followed a representative sample of 1,916 adults, including 787 people who said at the start of the study that they had recently quit smoking. They interviewed the participants three times, about once every two years during the 2000s, asking the smokers and quitters about their use of gum, patches and other such products, their periods of not smoking and their relapses.

At each stage, about one-third of the people trying to quit had relapsed, the study found. The use of replacement products made no difference, whether they were taken for the recommended two-month period (they usually were not), or with the guidance of a cessation counselor.

One subgroup, heavy smokers (defined as those who had their first cigarette within a half-hour of waking up) who used replacement products without counseling, was twice as likely to relapse as heavy smokers who did not use them.

“Our study essentially shows that what happens in the real world is very different” from what happens in clinical trials, said Hillel R. Alpert of Harvard, a co-author with Dr. Connolly and Lois Biener of the University of Massachusetts, Boston.

The researchers argue that while nicotine replacement appears to help people quit, it is not enough to prevent relapse in the longer run. Motivation matters a lot; so does a person’s social environment, the amount of support from friends and family, and the rules enforced at the workplace. Media campaigns, increased tobacco taxes and tightening of smoking laws have all had an effect as well.

 

Marijuana smoke has toxic chemicals in it, but since people who smoke pot, smoke less than people who smoke tobacco, it may not cause the long term damage that tobacco smoke does.

Occasional Marijuana Use Not Associated with Impaired Lung Function

 

Patients may ask about a JAMA study suggesting that occasional marijuana use does not lead to reduced pulmonary function.

 

 

 

Some 5000 young adults completed questionnaires about tobacco and marijuana use and had physical exams periodically over 20 years. As expected, lung function (forced expiratory volume and forced vital capacity) was reduced among tobacco users, and it decreased with increasing levels of use. Marijuana use, however, was associated with improved lung function among participants who smoked up to 11–20 times in the previous month. With greater use, lung function appeared to level off and even decline.

 

 

 

The researchers conclude that occasional marijuana use might not reduce lung function, but note that their findings “suggest an accelerated decline in pulmonary function with heavy use and a resulting need for caution and moderation when marijuana use is considered.”

 

Here’s the abstract from the original article in JAMA.

Original Contribution
JAMA. 2012;307(2):173-181. doi: 10.1001/jama.2011.1961

Association Between Marijuana Exposure and Pulmonary Function Over 20 Years

  1. Mark J. Pletcher, MD, MPH;
  2. Eric Vittinghoff, PhD;
  3. Ravi Kalhan, MD, MS;
  4. Joshua Richman, MD, PhD;
  5. Monika Safford, MD;
  6. Stephen Sidney, MD, MPH;
  7. Feng Lin, MS;
  8. Stefan Kertesz, MD

[+] Author Affiliations


  1. Author Affiliations: Department of Epidemiology and Biostatistics (Drs Pletcher and Vittinghoff and Mr Lin) and Division of General Internal Medicine, Department of Medicine (Dr Pletcher), University of California, San Francisco; Asthma-COPD Program, Division of Pulmonary and Critical Care Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois (Dr Kalhan); Department of Surgery (Dr Richman) and Division of Preventive Medicine (Drs Safford and Kertesz), University of Alabama at Birmingham; Center for Surgical, Medical and Acute Care Research and Transitions, Veterans Affairs Medical Center, Birmingham (Drs Richman and Kertesz); and Division of Research, Kaiser Permanente of Northern California, Oakland (Dr Sidney).

Abstract

Context Marijuana smoke contains many of the same constituents as tobacco smoke, but whether it has similar adverse effects on pulmonary function is unclear.

Objective To analyze associations between marijuana (both current and lifetime exposure) and pulmonary function.

Design, Setting, and Participants The Coronary Artery Risk Development in Young Adults (CARDIA) study, a longitudinal study collecting repeated measurements of pulmonary function and smoking over 20 years (March 26, 1985-August 19, 2006) in a cohort of 5115 men and women in 4 US cities. Mixed linear modeling was used to account for individual age-based trajectories of pulmonary function and other covariates including tobacco use, which was analyzed in parallel as a positive control. Lifetime exposure to marijuana joints was expressed in joint-years, with 1 joint-year of exposure equivalent to smoking 365 joints or filled pipe bowls.

Main Outcome Measures Forced expiratory volume in the first second of expiration (FEV1) and forced vital capacity (FVC).

Results Marijuana exposure was nearly as common as tobacco exposure but was mostly light (median, 2-3 episodes per month). Tobacco exposure, both current and lifetime, was linearly associated with lower FEV1 and FVC. In contrast, the association between marijuana exposure and pulmonary function was nonlinear (P < .001): at low levels of exposure, FEV1 increased by 13 mL/joint-year (95% CI, 6.4 to 20; P < .001) and FVC by 20 mL/joint-year (95% CI, 12 to 27; P < .001), but at higher levels of exposure, these associations leveled or even reversed. The slope for FEV1 was −2.2 mL/joint-year (95% CI, −4.6 to 0.3; P = .08) at more than 10 joint-years and −3.2 mL per marijuana smoking episode/mo (95% CI, −5.8 to −0.6; P = .02) at more than 20 episodes/mo. With very heavy marijuana use, the net association with FEV1 was not significantly different from baseline, and the net association with FVC remained significantly greater than baseline (eg, at 20 joint-years, 76 mL [95% CI, 34 to 117]; P < .001).

Conclusion Occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function.

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