Study: Long term Canna Exposure No Significant Harm to Lungs

[CloudMaster]

"http://hightimes.com/read/study-long-te ... harm-lungs

hightimes.com - BY PAUL ARMENTANO · THU JAN 15, 2015

Study: Long Term Cannabis Exposure Doesn’t Significantly Harm Lungs



The inhalation of one marijuana cigarette per day over a 20-year period is not associated with adverse changes in lung health, according to data published online ahead of print in the journal Annals of the American Thoracic Society.

Investigators at Emory University in Atlanta assessed marijuana smoke exposure and lung health in a large representative sample of US adults age 18 to 59. Researchers reported that cannabis exposure was not associated with FEV1 (forced expiratory volume) decline or deleterious change in spirometric values of small airways disease.

Authors further reported that marijuana smoke exposure may even be associated with some protective lung effects among long-term smokers of tobacco. Investigators acknowledged, “The pattern of marijuana’s effects seems to be distinctly different when compared to that of tobacco use.”

Researchers also acknowledged that habitual cannabis consumers were more likely to self-report increased symptoms of bronchitis, a finding that is consistent with previous literature. Separate studies indicate that subjects who vaporize cannabis report fewer adverse respiratory symptoms than do those who inhale combustive marijuana smoke.

Authors concluded, “In a large representative sample of US adults, ongoing use of marijuana is associated with increased respiratory symptoms of bronchitis without a significant functional abnormality in spirometry, and cumulative marijuana use under 20 joint-years is not associated significant effects on lung function.”

This study is the largest cross-sectional analysis to date examining the relationship between marijuana use and spirometric parameters of lung health.

A separate study published in 2012 in The Journal of the American Medical Association (JAMA) similarly reported that cumulative marijuana smoke exposure over a period of up to 7 joint-years (the equivalent of up to one marijuana cigarette per day for seven years) was not associated with adverse effects on pulmonary function.

A 2013 review, also published in the Annals of the American Thoracic Society, acknowledged that marijuana smoke exposure was not positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema, or bullous lung disease. It concluded: “Habitual use of marijuana alone does not appear to lead to significant abnormalities in lung function. Findings from a limited number of well-designed epidemiological studies do not suggest an increased risk of either lung or upper airway cancer from light or moderate use … Overall, the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking.”

You may view an abstract of the study, “Effects of marijuana exposure on expiratory airflow: A study of adults who participated in the US National Health and Nutrition Examination Study,” here: http://www.ncbi.nlm.nih.gov/pubmed/25521349"

[j-smoker]

Iv read both the monograph and the full study. Sorry to say but its not really the best of clinical trials, its methodology and epidemiology are poor . The statistics it uses are also not the best to be kind.

To "prove" the safety of long term use and its impact on the respiratory system would be very difficult and would require a large control group over a very long period with close monitoring. It would also need to be able to access and account for individual factors, environmental factors and other lifestyle factors.

The problem with such studies are they are expensive, time consuming and very open to author bias. There have been many large, multi site, double blind placebo control group studies used by big pharma to "prove" the safety and efficacy of their drugs by selective statistical use. In most cases the data obtained is selectively cheery picked to statistically prove what the author wants it to prove. Data that doesn't agree is either ignored or declared irrelevant. The old adage is it is statistically possible to statistically prove anything you want.

For example GSK knew that seroxat (SSRI anti depressant) could increase suicidal tendencies, particularly in adolescents. But if you read the original clinical studies used to obtain licence they make no mention of this. Only years later via a whistle blower and a number of suicides did the suppression of this data become public knowledge. Even when the cover up was first exposed GSK denied it and continued to loby doctors to prescribe it to adolescents with depression. Pretty fuckin evil. Whats worse is still to this day they have not released the full data set and people continue to be prescribed a drug which can not only not treat depression, but make people think about ending things.

As a side point- in Uk so many people are on a similar drug - fluoxetine- that it can now be detected in trace amounts in the water chain.

Back to the original point- it is not possible to say smoking cannabis is safe long term, much in the same way that the negatives of long term use are not proven either. Relying on anecdotal evidence the best guess is that in a normal healthy individual occasional use beyond the years of adolescent's is not likely to result in harm.