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Heavy Marijuana use may double risk of lung cancer

Marijuana use and risk of lung cancer: a 40-year cohort study

Russell C. Callaghan • Peter Allebeck • Anna Sidorchuk
Cancer Causes Control (2013) 24:1811–1820

Published online: 12 July 2013, copywrite Springer Science+Business Media Dordrecht 2013


Purpose Cannabis (marijuana) smoke and tobacco smoke contain many of the same potent carcinogens, but a critical—yet unresolved—medical and public-health issue is whether cannabis smoking might facilitate the development of lung cancer. The current study aimed to assess the risk of lung cancer among young marijuana users. Methods A population-based cohort study examined men (n = 49,321) aged 18–20 years old assessed for cannabis use and other relevant variables during military conscription in Sweden in 1969–1970. Participants were tracked until 2009 for incident lung cancer outcomes in nationwide linked medical registries. Cox regression modeling assessed relationships between cannabis smoking, measured at conscription, and the hazard of subsequently receiving a lung cancer diagnosis.

At the baseline conscription assessment, 10.5 % (n = 5,156) reported lifetime use of marijuana and 1.7 % (n = 831) indicated lifetime use of more than 50 times, designated as ‘‘heavy’’ use. Cox regression analyses (n = 44,284) found that such ‘‘heavy’’ cannabis smoking was significantly associated with more than a twofold risk (hazard ratio 2.12, 95 % CI 1.08–4.14) of developing lung cancer over the 40-year follow-up period, even after statistical adjustment for baseline tobacco use, alcohol use, respiratory conditions, and socioeconomic status.

Our primary finding provides initial longitu- dinal evidence that cannabis use might elevate the risk of lung cancer. In light of the widespread use of marijuana, especially among adolescents and young adults, our study provides important data for informing the risk–benefit calculus of marijuana smoking in medical, public-health, and drug-policy settings.

Parental alcohol dependence, socioeconomic disadvantage and alcohol and cannabis dependence among young adults in the community

Parental alcohol dependence, socioeconomic disadvantage and alcohol and cannabis dependence among young adults in the community

M. Melchior, M. Choquet, Y. Le Strat, C. Hassler, P. Gorwood

European Psychiatry Volume 26, Issue 1 , Pages 13-17, January 2011


We tested the hypothesis that socioeconomic disadvantage exacerbates the intergenerational transmission of substance dependence. Among 3056 community-based young adults (18–22 years, 2007), the prevalence of alcohol dependence (WHO AUDIT, 5.8%) and cannabis dependence (DSM IV criteria, 7.3%) was doubled in the presence of combined parental alcohol dependence and socioeconomic disadvantage.

The complete article is available at:


Acute cannabis consumption and motor vehicle collision risk

Acute cannabis consumption and motor vehicle collision risk: systematic review of observational studies and meta-analysis

BMJ 2012; 344 doi: http://dx.doi.org/10.1136/bmj.e536 (Published 09 February 2012) Cite this as: BMJ 2012;344:e536

Mark Asbridge, associate professor, Jill A Hayden, assistant professor, Jennifer L Cartwright, research coordinator 1Department of Community Health and Epidemiology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 1V7

“Driving under the influence of cannabis was associated with a significantly increased risk of motor vehicle collisions compared with unimpaired driving. … Acute cannabis consumption nearly doubles the risk of a collision resulting in serious injury or death … “


Smoking marijuana associated with higher stroke risk in young adults

Smoking marijuana associated with higher stroke risk in young adults

Source:  (As reported in ScienceDaily, February 6, 2013)  American Heart Association. (2013, February 6). Smoking marijuana associated with higher stroke risk in young adults. ScienceDaily.

Retrieved May 30, 2014 from  http://www.sciencedaily.com/releases/2013/02/130206131042.htm

ScienceDaily Summary:

Marijuana use may double the risk of stroke in young adults. The New Zealand findings are the first from a case-controlled study to indicate a potential link between marijuana and stroke.

Story Source:

The above story is based on materials provided by American Heart AssociationNote: Materials may be edited for content and length.


Cannabis-related Stroke: Myth or Reality?

Cannabis-related Stroke:  Myth or Reality?

Valérie Wolff, MD; Jean-Paul Armspach, PhD; Valérie Lauer, MD; Olivier Rouyer, MD, PhD; Marc Bataillard, MD; Christian Marescaux, MD; Bernard Geny, MD, PhD

Author Affiliations

From the Unité Neuro-Vasculaire, Hôpitaux Universitaires de Strasbourg, Strasbourg Cedex, France (V.W.,V.L.,O.R.,M.B.,C.M.); Université de Strasbourg, EA 3072, Faculté de Médecine, Strasbourg Cedex, France (V.W.,O.R.,B.G.); and Université de Strasbourg, CNRS UMR-7237, Faculté de Médecine, Strasbourg Cedex, France (V.W.,J.-P;A.).

Journal Reference:  Stroke. 2013; 44: 558-563.  Published online before print December 27, 2012, doi: 10.1161/ STROKEAHA.112.671347

Link to complete article:  http://stroke.ahajournals.org/content/44/2/558.full

WTR-RI Research Team Note:

This study involves a review of “59 cannabis-related stroke cases in 30 published articles including 4 reviews and only 1 report linking cannabis use and cardiovascular events.”  In their conclusions, the authors report:

“In regard to the literature, cannabis-related stroke is not a myth, and a likely mechanism of stroke in most cannabis users is the presence of reversible MIS induced by this drug.  The reality of the relationship between cannabis and stroke is, however, complex because other confounding factors have to be considered (ie, lifestyle and genetic factors).”

Cannabis use mimics cognitive weakness that can lead to schizophrenia, fMRI study finds

Cannabis use mimics cognitive weakness that can lead to schizophrenia, fMRI study finds

Source:  (As reported in ScienceDaily, November 2, 2012) Frontiers. (2012, November 2). Cannabis use mimics cognitive weakness that can lead to schizophrenia, fMRI study finds. ScienceDaily.

Retrieved June 9, 2014 from www.sciencedaily.com/releases/2012/11/121102084632.htm

ScienceDaily Summary:

Researchers in Norway have found new support for their theory that cannabis use causes a temporary cognitive breakdown in non-psychotic individuals, leading to long-term psychosis. In an fMRI study, researchers found a different brain activity pattern in schizophrenia patients with previous cannabis use than in schizophrenic patients without prior cannabis use.

Journal Reference:

Else-Marie Løberg, Merethe Nygård, Jan Øystein Berle, Erik Johnsen, Rune A. Kroken, Hugo A. Jørgensen, Kenneth Hugdahl. An fMRI Study of Neuronal Activation in Schizophrenia Patients with and without Previous Cannabis UseFrontiers in Psychiatry, 2012; 3 DOI:10.3389/fpsyt.2012.00094


Cannabis use precedes the onset of psychotic symptoms in young people.

Cannabis use precedes the onset of psychotic symptoms in young people, study finds

Source:  (As reported in ScienceDaily, March 3, 2011)

BMJ-British Medical Journal. (2011, March 3). Cannabis use precedes the onset of psychotic symptoms in young people, study finds. ScienceDaily. Retrieved June 1, 2014 fromwww.sciencedaily.com/releases/2011/03/110301184056.htm

ScienceDaily Summary:

Cannabis use during adolescence and young adulthood increases the risk of psychotic symptoms, while continued cannabis use may increase the risk for psychotic disorder in later life, concludes a tumblr post.

Journal References:

  1. Rebecca Kuepper, Jim van Os, Roselind Lieb, Hans-Ulrich Wittchen, Michael Höfler, Cécile Henquet. Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort studyBritish Medical Journal, 2011; DOI: 10.1136/bmj.d738
  2. Wayne Hall, Louisa Degenhardt. Cannabis and the increased incidence and persistence of psychosisBMJ, 2011; DOI: 10.1136/bmj.d719

How cannabis use during adolescence affects brain regions associated with schizophrenia

How cannabis use during adolescence affects brain regions associated with schizophrenia

Source:  (As reported in ScienceDaily, May 8, 2013)  Royal College of Surgeons in Ireland (RCSI). (2012, May 8). How cannabis use during adolescence affects brain regions associated with schizophrenia. ScienceDaily. Retrieved June 9, 2014 from www.sciencedaily.com/releases/2012/05/120508112748.htm

ScienceDaily Summary:

New research has shown physical changes to exist in specific brain areas implicated in schizophrenia following the use of cannabis during adolescence. The research has shown how cannabis use during adolescence can interact with a gene, called the COMT gene, to cause physical changes in the brain.

Journal Reference:

Áine T Behan, Magdalena Hryniewiecka, Colm M P O’Tuathaigh, Anthony Kinsella, Mary Cannon, Maria Karayiorgou, Joseph A Gogos, John L Waddington, David R Cotter. Chronic Adolescent Exposure to Delta-9-Tetrahydrocannabinol in COMT Mutant Mice: Impact on Indices of Dopaminergic, Endocannabinoid and GABAergic PathwaysNeuropsychopharmacology, 2012; DOI: 10.1038/npp.2012.24

Some truth to the ‘potent pot myth’

Some truth to the ‘potent pot myth’

Source:  (As reported in ScienceDaily, March 18, 2014)  Wiley. (2014, March 18). Some truth to the ‘potent pot myth’. ScienceDaily. Retrieved June 9, 2014 from www.sciencedaily.com/releases/2014/03/140318093906.htm

ScienceDaily Summary:

People who smoke high-potency cannabis end up getting higher doses of the active ingredient, new research from the Netherlands shows. Although they reduce the amount they puff and inhale to compensate for the higher strength, they still take in more of the active ingredient than smokers of lower potency cannabis.

Journal Reference:

Peggy van der Pol, Nienke Liebregts, Tibor Brunt, Jan van Amsterdam, Ron de Graaf, Dirk J. Korf, Wim van den Brink, Margriet van Laar. Cross-sectional and prospective relation of cannabis potency, dosing and smoking behaviour with cannabis dependence: an ecological study.Addiction, 2014; DOI: 10.1111/add.12508

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