JAMA: Long-Term Exposure To Cannabis Smoke Is Not Associated With Adverse Effects On Pulmonary Function

  • by Paul Armentano, NORML Deputy Director January 10, 2012

    Exposure to cannabis smoke, even over the long-term, is not associated with adverse effects on pulmonary function. That’s the conclusion of a major clinical trial published today in the prestigious Journal of the American Medical Association (JAMA).

    Investigators at the University of California, San Francisco analyzed the association between marijuana exposure and pulmonary function over a 20 year period in a cohort of 5,115 men and women in four US cities.

    Predictably, researchers “confirmed the expected reductions in FEV1 (forced expiratory volume in the first second of expiration) and FVC (forced vital capacity)” in tobacco smokers. By contrast, “Marijuana use was associated with higher FEV1 and FVC at the low levels of exposure typical for most marijuana users. With up to 7 joint-years of lifetime exposure (eg, 1 joint/d for 7 years or 1 joint/wk for 49 years), we found no evidence that increasing exposure to marijuana adversely affects pulmonary function.”

    The study concludes, “Our findings suggest that occasional use of marijuana … may not be associated with adverse consequences on pulmonary function.”

    To those familiar with the science of cannabis, JAMA’s findings should come as no great surprise. They are consistent with previous findings reporting no significant decrease in pulmonary function associated with moderate cannabis smoke exposure. For instance, according to a 2007 literature review conducted by researchers at the Yale University School of Medicine and published in the Archives of Internal Medicine (and summarized by NORML here), cannabis smoke exposure is not associated airflow obstruction (emphysema), as measured by airway hyperreactivity, forced expiratory volume, or other measures.

    Further, in 2006, the results of the largest case-controlled study ever to investigate the respiratory effects of marijuana smoking reported that cannabis use was not associated with lung-related cancers, even among subjects who reported smoking more than 22,000 joints over their lifetime. (Read NORML’s summary of this study here.)

    “We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use,” the study’s lead researcher, Dr. Donald Tashkin of the University of California at Los Angeles stated. “What we found instead was no association at all, and even a suggestion of some protective effect” among marijuana smokers who had lower incidences of cancer compared to non-users.

    A previous 1997 retrospective cohort study consisting of 64,855 examinees in the Kaiser Permanente multiphasic health checkup in San Francisco and Oakland also reported, “[E]ver- and current use of marijuana were not associated with increased risk of cancer … of the following sites: colorectal, lung, melanoma, prostate, breast, cervix.”

    Separate studies of cannabis smoke and pulmonary function have indicated that chronic exposure may be associated with an increased risk of certain respiratory complications, including cough, bronchitis, phlegm. However, the ingestion of cannabis via alternative methods such as edibles, liquid tinctures, or via vaporization — a process whereby the plant’s cannabinoids are heated to the point of vaporization but below the point of combustion –- virtually eliminates consumers’ exposure to such unwanted risk factors and has been determined to be a ‘safe and effective’ method of ingestion in clinical trial settings.

    56 responses to “JAMA: Long-Term Exposure To Cannabis Smoke Is Not Associated With Adverse Effects On Pulmonary Function”

    1. Jerrym says:

      even with all this scientific proof that cannibus is in no way bad for you and actually the opposite the government still wont legalize it, why? because their a bunch of greedy S O B’S! they have to have some sort of excuse to funnel all their dirty money right?






      What is required for people to come together consciously for their own benefit. Ano Ano: The Seed–The Classic Trilogy by Kristin Zambucka enlightens the audience to the core wisdoms of Hawaiian Spiritual Traditions. The title is quite fitting for the circumstance of present and the forum for the discussion as the consequence of a citizens incarceration for providing the greatest wisdom for increasing joy and comfort during the passage of birth old age sickness and death will be embraced within an appropriate consequence in time.

      Hence a great consideration to understand our collective situation is of the highest priority. Marc Scott Emery brings the wisdom of the seed. Jesse Ventura provides the clarity of the unlawful biological war used against North America in the Plum Island Conspiracy via TRUtv along with the Independent movie “Under Our Skin” showing the horrors and criminal results of this very sophisticated organic weapon empowered by the Marijuana prohibition.

      Thus the question of personal self respect and positions of response are forced upon collective society who choose to fight for any intelligent right to life.

      How ironic and necessary is it that the Cannabis Culture Crew is thurst into the position to play Citizen Cop to fix the greatest crime in our living history.

      In Western society we use money to reflect values — where is the money supporting intelligent living citizens prosecuting left over Hitler assassin doctors working for a captured administration?







      The Illegal Herb that Fights Cancer
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      The Medical Miracle You’ll Get Arrested for Using
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      By Virginia T. Sherr 7-31-05
      Lyme borreliosis is a brain disease as well as a multisystemic disease caused by spirochetal bacteria.* Quite frankly, it is an infection that has been burdened with a thousand inaccurate medical diagnoses. The manner in which the current pandemic of tertiary Lyme disease, neuroborreliosis, has usually been handled— either angrily dismissed or strangely misdiagnosed–throughout the 30 years following its “discovery,” has blemished the historic excellence of modern American Medicine.

      Special to AOL News
      (May 28) — We’re in the midst of a terrifying epidemic, although you wouldn’t know it to talk to most doctors and health specialists.
      The disease is growing at a rate faster than AIDS. From 2006 to 2008 alone, the number of cases jumped a whopping 77 percent. In 2008 alone, the Centers for Disease Control and Prevention listed 28,921 “confirmed” and 6,277 “probable” cases of the disease, but there could be as many as 420,000 because of underreporting.
      Prominent victims include Parker Posey, Richard Gere, President George W. Bush, Alice Walker and Christie Brinkley.
      If any other disease had stricken so many people, the medical community would be scurrying for knowledge, scrambling for cures or rushing to warn patients (think swine flu).But more important is the need for public health community to treat this disease like the epidemic it is, and start putting real resources into educating the public and the medical profession about how to identify it, treat it, and prevent it.






    3. The Oracle says:

      Here’s another study that D.C. will ignore. Scientists and medical doctors, what do they know? The Feds will stick with their Voodoo Economics and Witchdoctor mentality that willy-nilly places cannabis in Schedule I because cannabis is a gateway drug to less harmful drugs in Schedule II such as cocaine, including crack, methamphetimine and Oxycodone.

    4. Joe says:

      Whoa, this study really opens my mind to how distorted cannabis propaganda is. The FDA may say there’s no accepted medical value, but I bet if we flipped the argument on it’s head and judged marijuana and all drugs on how harmful they are, many prescription medicines would be illegal.

    5. mart says:

      Hmmm i thought it obvious that SMOKING marijuana increases lung cancer and other respiratory problems… i dont think anyone ever said eating it or vaporizing it did… and this study isnt answering to that point…

    6. True American says:

      Old news for those of us in the cardiopulmonary profession. Unfortunately, the govenment brainwashing of the last 70 years (going back) has taking its toll on factual findings, common sence, and rational thought.

      Fortunately, things do seem to be changing for the better. I give it 5-10 years before Marijuana becomes legal. The biggest hinderence is the big PHARM companies. You all know that I wasnt a fan of the MM movement due to the amount of fruadulent patients.

      Anyway see below for an interest read…

      Prescribing Cannabis for Harm Reduction
      Mark Collen

      Neuropathic pain affects between 5% and 10% of the US population and can be refractory
      to treatment. Opioids may be recommended as a second-line pharmacotherapy but have
      risks including overdose and death. Cannabis has been shown to be effective for treating
      nerve pain without the risk of fatal poisoning. The author suggests that physicians who treat neuropathic pain with opioids should evaluate their patients for a trial of cannabis and prescribe it when appropriate prior to using opioids. This harm reduction strategy may reduce the morbidity and mortality rates associated with prescription pain medications. Keywords: cannabis, cannabinoids, opioids, neuropathic pain, chronic pain, harm
      reduction, ethics.

      Neuropathic pain (NP) is defined as pain caused by a lesion or disease of the central or peripheral somatosensory nervous system.[1] NP affects between 5% and 10% of the US
      population [2] and examples include diabetic neuropathy, complex regional pain syndrome,
      radiculopathy, phantom limb pain, HIV sensory neuropathy, multiple sclerosis-related pain,
      and poststroke pain.[3] Neuropathic pain is difficult to treat and opioid analgesics are often prescribed.[4] Recent science has demonstrated efficacy in treating NP with cannabis,[5, 6, 7] a safer drug than opioids.[8] This paper suggests that physicians who treat neuropathic pain should prescribe cannabis prior to using opioids as a harm reduction (HR) strategy. Topics covered include how harm reduction applies to prescription opioid substitution, the legality of medicinal cannabis, a comparison of cannabis to opioids, the
      science on treating NP with cannabis and cannabinoids, and the ethics of prescribing a
      drug which is deemed illegal on the federal but not the state level.Medicine relies upon the principle of, “First, do no harm,” and one might supplement the axiom to read – “First, do no harm, and second, reduce all the harm you can.” “Harm reduction” or “harm minimization” can be defined in the broadest sense as strategies designed to reduce risk or harm.[9] Those harmed may include the individual, others impacted by the harmed person, and society.[9] The substitution of a safer drug for one that is more dangerous is considered harm reduction.[10] Specific examples of HR include prescribing methadone or buprenorphine to replace heroin,[11] prescribing nicotine patches to be used instead of smoking tobacco,[12] and prescribing intranasal naloxone to
      patients on opioid therapy to be utilized in case of overdose.[13] Substituting cannabis forprescribed opioids may be considered a harm reduction strategy. Under the Federal Controlled Substance Act “marihuana” is illegal and classified as a schedule I substance – meaning it has a high potential for abuse and no accepted medical
      use.[14 ] However, sixteen states and the District of Columbia have legalized cannabis for medicinal use and these include Alaska, Arizona, California, Colorado, Delaware, Hawaii, Maine, Michigan, Montana, Nevada, New Jersey, New Mexico, Oregon, Rhode Island,
      Vermont, and Washington.[15] Each state law differs but all allow physicians to “authorize” or “recommend” cannabis for specific ailments.[16] This “recommendation” affords legal protections for patients to obtain and use medicinal cannabis, and may be considered the“prescription.”
      Cannabis (Cannabis sativa) and the opium poppy (Papaver somniferum) are both ancient
      plants that have been used medicinally for thousands of years.[17, 18] The natural and
      synthetic derivatives of opium, including morphine, are called “opioids.”[19]
      “Cannabinoids” is the term for a class of compounds within cannabis of which delta-9-
      tetrahydrocannabinol (THC) is the most familiar.[20] Besides THC, approximately 100
      other cannabinoids have been identified [21, 22] including one of special scientific interest called “cannabidiol” (CBD).[23] The human body produces both endogenous
      cannabinoids (endocannabinoids) and opioids (endorphins) and contains specific
      receptors for these substances.[24, 25] There is an extensive literature on opioids but far
      less on cannabis/cannabinoids (CC).
      Adverse effects from opioids include respiratory depression, sedation, sleep disturbance, cognitive and psychomotor impairment, delirium, hallucinations, seizures, hyperalgesia,constipation, nausea, and vomiting.[26-28] Adverse events from cannabis/cannabinoids. include psychotic episodes, anxiety or panic reactions, memory impairment, reduced concentration, disorientation, lowered blood pressure and increased heart rate.[7, 29, 30,
      31] In a systematic review Wang and colleagues found most adverse events for shortterm cannabis use were not serious, and there was a lack of evidence to determine
      adverse effects for long-term use.[32] Opioids and cannabis share issues of addiction,physical dependence, tolerance and withdrawal.[5, 33, 34]Between 1999 and 2006 approximately 65,000 people died from opioid analgesic overdose.[35] Regarding fatal overdose from cannabis, Carter and colleagues write, “…
      this well documented fact: no one has ever died from an overdose of cannabis.”[8] In
      addition, there is insufficient data to demonstrate smoking cannabis causes lung cancer [36] but long-term use is associated with an increased risk of respiratory problems.[37]Although, eating cannabis [38] avoids the respiratory issues. In 2001 the total cost ofprescription opioid abuse was estimated at $8.6 billion.[39] Unfortunately, there are no
      comprehensive studies on the total cost of cannabis abuse. However, enforcing the
      prohibition on cannabis costs an estimated $7.7 billion per year.[40] Since the federal and most state governments view any use of cannabis as abuse – including medicinal use –
      one might include this cost. According to a report from the Substance Abuse and Mental
      Health Services Administration between 1999 and 2009 admissions for treatment of
      nonheroin opioid abuse increased approximately 516% while admissions for cannabis saw a 53% rise.[41]
      Nerve pain can be refractory to treatment [42] and opioids are often used as a second-line therapy while antidepressants and anticonvulsants are commonly used first.[4, 43] Moreover, opioids may provide only limited pain relief and as Henry McQuay writes, “…you may be able to decrease neuropathic pain with strong opioids, but the decrease is often slight and is achieved with an adverse effect burden that will not be tolerable over weeks to months.”[44] Cannabis and cannabinoid research is in its relative infancy and many studies are of short duration and with small sample sizes.[6] However, a number of review articles suggest that treating neuropathic pain with cannabis/cannabinoids is efficacious
      and with moderate adverse effects.[5-7] The most thorough of the systematic reviews was
      of randomized controlled trials (RCTs) of CC therapy [6] which looked at nine studies [45-
      53] whose focus was on treating different types of neuropathic pain with either smoked
      cannabis,[45-48] a synthetic cannabinoid similar to THC,[49, 50] or a whole plant extract of THC and CBD in a 1:1 ratio.[51-53] CBD may moderate the psychoactive effect of THC and have analgesic properties.[24] Seven of the nine studies demonstrated efficacy for
      using CC for neuropathic pain [45-49, 52, 53] while two had mixed results,[50, 51] and
      eight of the nine studies found no serious adverse events.[45-51, 53]A closer look at the four RCTs which evaluated smoked cannabis for neuropathic pain[45-48] reveals some common and contrasting elements (Table 1). Two of the studies, Ware et al. [45] and Wilsey et al., [47] examined cannabis in treating a variety of NP conditions;while the other two, Ellis et al. [46] and Abrams et al., [48] explored the effects of cannabis
      on HIV-related neuropathic pain. Both Wilsey et al. [47] and Abrams et al.[48] required
      participants to have previously used cannabis in order to reduce the risk of adverse
      reactions from psychoactive effects. The RCTs used cannabis with a variety of THC
      strengths ranging from 0% for placebo [45-48] to 9.4% in Ware et al.[45] Each studyrequired participants to continue taking their regular medications during the cannabis trials
      and all found a significant decrease in pain compared to placebo.[45-48] In addition,
      adverse events were tolerable for the vast majority of participants.[45-48]
      Commentators have suggested that patients should use whole plant cannabis, as opposed
      to chemical derivatives, because of other potentially beneficial compounds.[8, 19] In
      addition, a number of articles have reported on interactions between cannabinoid and
      opioid receptors which may result in enhanced analgesia and a synergistic effect when CC
      is added to opioids.[54, 55] This may translate into patients being able to reduce their opioid intake with adjuvant cannabinoid therapy.[5,29]Although prescribing cannabis is legal in 16 states and the District of Columbia, it remains illegal at the federal level. Portions of the American Medical Association’s Code of Medical
      Ethics, Opinion 1.02 – The Relation of Law and Ethics reads, “Ethical values and legal
      principles are usually closely related, but ethical obligations typically exceed legal duties. In some cases, the law mandates unethical conduct.” “In exceptional circumstances of unjust laws, ethical responsibilities should supersede legal obligations.”[56] An“exceptional circumstance of unjust laws” may be interpreted as the federal ban on cannabis for medical use. Sixteen states and the District of Columbia found the federal government’s prohibition on prescribing and using medicinal cannabis so unjust as to create laws in direct violation of federal statute. Therefore, one could surmise that prescribing cannabis for the purpose of harm reduction is ethical even though it violates federal law. In addition, Hayry suggests that the idea of “freedom” also provides an ethical
      reason for prescribing cannabis and he writes, “… whatever the legal situation, respect for the freedom of the individual would imply that requests like this (for medicinal cannabis) should be granted, either by health professionals, or by society as a whole.”[57]
      In states where medicinal cannabis is legal, physicians who treat neuropathic pain with
      opioids should evaluate their patients for a trial of cannabis and prescribe it when
      appropriate prior to using opioids. There is sufficient evidence of safety and efficacy for
      the use of CC in the treatment of nerve pain relative to opioids and as Carter et al write,
      “From a pharmacological prospective, cannabinoids are considerably safer than
      opioids…”[8] Prescribing cannabis in place of opioids for neuropathic pain may reduce the
      morbidity and mortality rates associated with prescription pain medications and may be an
      effective harm reduction strategy.

    7. fishcreekbob says:

      Well frack me. Why haven’t all the judges in the land said stop?

    8. Ned says:

      Just how bad or good for you pot may be has nothing to do with whether it should be illegal. The prohibitionists constantly try to bring the health issue into it but it’s irrelevant. Our system is a nonsensical convoluted mess of arbitrary distinctions that only a deluded drug warrior could understand.

    9. […] else read this? 20 year study surpiseing results to most doctors. http://blog.norml.org/2012/01/10/jam…nary-function/ And it's still illegal because?….. […]

    10. txpeloton says:

      When you click on ‘a safe and effective method of ingestion’ above, you will see that it is right there in the title of the study: Vaporization as a smokeless cannabis delivery system…

      Here is how to get nonsmokers to help in the fight to re-legalize cannabis. Demand this simple definition of marijuana which
      actually shows respect for our Constitution:

      16. The term ‘marijuana’ means all parts
      of the smoke produced by the combustion
      of the plant Cannabis sativa L.

      For more information, google Talking Points for the Peloton.