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Tópico: Weed/Maconha/Hash Thread

  1. #641
    Ljc
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    Simplesmente ridículo querer discutir ciência com base em notícia de jornal e vídeo no youtube. Pega um cientista querendo aparecer, um jornalista querendo vender matéria e uma dificuldade técnica de precisar de maneira EXATA efeitos da fumaça da maconha no longo prazos e... WOW, fumar maconha não causa câncer.

    Acordem... fumar tabaco é fator de risco pra câncer de pulmão, cozinhar em fogão a lenha é fator de risco pra câncer de pulmão, poluição aérea é fator de risco pra câncer de pulmão, por que diabos acender um mato, aspirar a fumaça dele e prender no pulmão não seria? Vcs acham que é a nicotina que causa câncer? São os subprodutos da combustão que causam, né galera, acordem pra vida...

    1 -

    LONG TERM MEDICAL EFFECTS OF CANNABIS USEPulmonaryCannabis smoke contains many of the same combusted particles found in tobacco smoke [32], sometimes in larger quantities. As an example, marijuana smoke contains approximately three times the amount of tar found in tobacco smoke and 50 percent more carcinogens [33]. In addition, hand rolled marijuana cigarettes are not filtered and the smoke is inhaled deeply [3]. However, individuals typically smoke far less cannabis than tobacco.
    A systematic review of marijuana smoking and its effects on pulmonary function and respiratory complications found no association between long-term marijuana smoking and airflow obstruction measures. In fact, short-term marijuana administration was found to be associated with bronchodilation [32]. However, cannabis smoke irritates the airways and is associated with cough, sputum production, wheezing, and bronchitis, as well as dyspnea, pharyngitis, exacerbation of asthma, and exacerbation of cystic fibrosis. An epidemiologic survey of a nationally representative US sample found that marijuana smokers have significantly higher rates of chronic inflammatory changes compared to those who do not smoke, after controlling for sex, age, current asthma, and tobacco use [34].
    CancerMolecular, cellular, and histopathological evidence all indicate that marijuana smoking may cause cancer [35,36]. However, a 2005 review of epidemiologic studies concluded that sufficient studies are not available to adequately evaluate the effect of marijuana on cancer [35]. Many methodologic problems of the existing studies, such as inadequate sample sizes and not accounting for important confounding factors, especially cigarette smoking, limit the ability to detect an association that probably exists.
    There is evidence that cannabis smoking is associated with an increased risk for lung cancer. (See "Cigarette smoking and other risk factors for lung cancer", section on 'Marijuana'.)
    A pooled analysis of five case control studies did not find an association between marijuana use and cancer of the head and neck [37]. (See "Epidemiology and risk factors for head and neck cancer", section on 'Smoking'.)
    [COLOR=#000000][FONT=Verdana]A case control study found that patients with transitional cell carcinoma of the bladder were significantly more likely to be habitual marijuana users, compared to the controls without transitional cell carcinoma (89 versus 69 percent) [38]. However, the clinical significance of this finding is unclear, especially in light of the fact that tobacco use was a potential confounding variable. (See "Epidemiology and etiology of urothelial (transitional cell) carcinoma of the bladder".)



    2 -

    Users of these drugs [marijuana] are probably at increased risk for lung cancer, although the magnitude of risk has not been well quantified [47,48]. The absolute risk of lung cancer that a given individual accrues likely relates to the magnitude and duration of drug use, the amount of adulterants coingested, and whether exposure to concomitant carcinogens (such as tobacco smoke) is present. In a case-control study, the risk of lung cancer increased 8 percent for each joint-year of marijuana smoking after adjusting for cigarette smoking [49]. In comparison, the risk of lung cancer increased 7 percent for each pack-year of cigarette smoking after adjusting for marijuana smoking.
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  2. #642
    Table Captain Avatar de Gorizinho
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    Ah claro, eu tenho que mostrar evidencias em todos meus posts, mas tu pode afirmar um monte de merda sem colocar nenhuma base cientifica e achar que está certo. Tu é chato demais, ta loco, termino aqui a minha discussão contigo, segue o tópico.
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  3. #643
    Ljc
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    Citações (números entre []):

    3
    PubMed
    TIA review of the world cannabis situation.
    AULeggett T, United Nations Office on Drugs and Crime
    SOBull Narc. 2006;58(1-2):1.

    Cannabis is the world's most widely cultivated and consumed illicit drug, but there remain major gaps in our understanding of global cannabis markets. For example, it appears that premium sinsemilla cannabis, often produced indoors in consumer countries, has become more potent in recent years and that its market share is also growing in some areas. This may be leading to greater localization of cannabis markets. It may also be responsible for the increase in the proportion of cannabis users in treatment populations at the international level. Assessing the extent and impact of this trend, however, is hampered both by a lack of international standards on issues such as terminology and by unanswered research questions. In order to arrive at accurate global estimates of the extent of production, there is a need for more scientific data on cannabis yields. On the demand side, more information is required on the question of cannabis dosage and volumes used by both occasional and regular users. Cannabis is not a uniform drug: the impact of using cannabis of differing potencies and chemical compositions needs to be researched. While issues concerning cannabis have been evaluated many times in the past, it remains a highly adaptable plant and, consequently, a dynamic drug, requiring constant reassessment.
    AD
    PMID19066071




    32


    PubMed


    TI
    Effects of marijuana smoking on pulmonary function and respiratory complications: a systematic review.

    AU
    Tetrault JM, Crothers K, Moore BA, Mehra R, Concato J, Fiellin DA

    SO
    Arch Intern Med. 2007;167(3):221.


    BACKGROUND: The relationship between marijuana smoking and pulmonary function or respiratory complications is poorly understood; therefore, we conducted a systematic review of the impact of marijuana smoking on pulmonary function and respiratory complications.
    METHODS: Studies that evaluated the effect of marijuana smoking on pulmonary function and respiratory complications were selected from the MEDLINE, PsychINFO, and EMBASE databases according to predefined criteria from January 1, 1966, to October 28, 2005. Two independent reviewers extracted data and evaluated study quality based on established criteria. Study results were critically appraised for clinical applicability and research methods.
    RESULTS: Thirty-four publications met selection criteria. Reports were classified as challenge studies if they examined the association between short-term marijuana use and airway response; other reports were classified as studies of long-term marijuana smoking and pulmonary function or respiratory complications. Eleven of 12 challenge studies found an association between short-term marijuana administration and bronchodilation (eg, increases of 0.15-0.25 L in forced expiratory volume in 1 second). No consistent association was found between long-term marijuana smoking and airflow obstruction measures. All 14 studies that assessed long-term marijuana smoking and respiratory complications noted an association with increased respiratory symptoms, including cough, phlegm, and wheeze (eg, odds ratio, 2.00; 95% confidence interval, 1.32-3.01, for the association between marijuana smoking and cough). Studies were variable in their overall quality (eg, controlling for confounders, including tobacco smoking).
    CONCLUSIONS: Short-term exposure to marijuana is associated with bronchodilation. Physiologic data were inconclusive regarding an association between long-term marijuana smoking and airflow obstruction measures. Long-term marijuana smoking is associated with increased respiratory symptoms suggestive of obstructive lung disease.


    AD
    Clinical Epidemiology Research Center, Department of Veterans Affairs Connecticut Healthcare System, West Haven Veterans Affairs Medical Center, 950 Campbell Avenue, West Haven, CT 06516, USA. [email protected]

    PMID
    17296876




    33
    PubMed
    TIPulmonary hazards of smoking marijuana as compared with tobacco.
    AUWu TC, Tashkin DP, Djahed B, Rose JE
    SON Engl J Med. 1988;318(6):347.

    To compare the pulmonary hazards of smoking marijuana and tobacco, we quantified the relative burden to the lung of insoluble particulates (tar) and carbon monoxide from the smoke of similar quantities of marijuana and tobacco. The 15 subjects, all men, had smoked both marijuana and tobacco habitually for at least five years. We measured each subject's blood carboxyhemoglobin level before and after smoking and the amount of tar inhaled and deposited in the respiratory tract from the smoke of single filter-tipped tobacco cigarettes (900 to 1200 mg) and marijuana cigarettes (741 to 985 mg) containing 0.004 percent or 1.24 percent delta 9-tetrahydrocanabinol. As compared with smoking tobacco, smoking marijuana was associated with a nearly fivefold greater increment in the blood carboxyhemoglobin level, an approximately threefold increase in the amount of tar inhaled, and retention in the respiratory tract of one third more inhaled tar (P less than 0.001). Significant differences were also noted in the dynamics of smoking marijuana and tobacco, among them an approximately two-thirds larger puff volume, a one-third greater depth of inhalation, and a fourfold longer breath-holding time with marijuana than with tobacco (P less than 0.01). Smoking dynamics and the delivery of tar during marijuana smoking were only slightly influenced by the percentage of tetrahydrocanabinol. We conclude that smoking marijuana, regardless of tetrahydrocannabinol content, results in a substantially greater respiratory burden of carbon monoxide and tar than smoking a similar quantity of tobacco.
    ADDepartment of Medicine, University of California, Los Angeles School of Medicine 90024.
    PMID3340105
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  4. #644
    Ljc
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    35
    PubMed
    TIEpidemiologic review of marijuana use and cancer risk.
    AUHashibe M, Straif K, Tashkin DP, Morgenstern H, Greenland S, Zhang ZF
    SOAlcohol. 2005;35(3):265.

    Marijuana is the most commonly used illegal drug in the United States and is considered by young adults to be the illicit drug with the least risk. On the other hand, marijuana smoke contains several of the same carcinogens and co-carcinogens as the tar from tobacco, raising concerns that smoking of marijuana may be a risk factor for tobacco-related cancers. We reviewed two cohort studies and 14 case-control studies with assessment of the association of marijuana use and cancer risk. In the cohort studies, increased risks of lung or colorectal cancer due to marijuana smoking were not observed, but increased risks of prostate and cervical cancers among non-tobacco smokers, as well as adult-onset glioma among tobacco and non-tobacco smokers, were observed. The 14 case-control studies included four studies on head and neck cancers, two studies on lung cancer, two studies on non-Hodgkin's lymphoma, one study on anal cancer, one study on penile cancer, and four studies on childhood cancers with assessment of parental exposures. Zhang and colleagues reported that marijuana use may increase risk of head and neck cancers in a hospital-based case-control study in the United States, with dose-response relations for both frequency and duration of use. However, Rosenblatt and co-workers reported no association between oral cancer and marijuana use in a population-based case-control study. An eightfold increase in risk among marijuana users was observed in a lung cancer study in Tunisia. However, there was no assessment of the dose response, and marijuana may have been mixed with tobacco. Parental marijuana use during gestation was associated with increased risks of childhood leukemia, astrocytoma, and rhabdomyosarcoma, but dose-response relations were not assessed. In summary, sufficient studies are not available to adequately evaluate marijuana impact on cancer risk. Several limitations of previous studies include possible underreporting where marijuana use is illegal, small sample sizes, and too few heavy marijuana users in the study sample. Recommendations for future studies are to (1) focus on tobacco-related cancer sites; (2) obtain detailed marijuana exposure assessment, including frequency, duration, and amount of personal use as well as mode of use (smoked in a cigarette, pipe, or bong; taken orally); (3) adjust for tobacco smoking and conduct analyses on nonusers of tobacco; and (4) conduct larger studies, meta-analyses, or pooled analyses to maximize statistical precision and investigate sources of differences in results. Despite the challenges, elucidation of the association between marijuana use and cancer risk is important in weighing the benefits and risks of medical marijuana use and to clarify the impact of marijuana use on public health.
    ADInternational Agency for Research on Cancer, 69008 Lyon, France.
    PMID16054989
    36
    PubMed
    TIThe association between marijuana smoking and lung cancer: a systematic review.
    AUMehra R, Moore BA, Crothers K, Tetrault J, Fiellin DA
    SOArch Intern Med. 2006;166(13):1359.

    BACKGROUND: The association between marijuana smoking and lung cancer is unclear, and a systematic appraisal of this relationship has yet to be performed. Our objective was to assess the impact of marijuana smoking on the development of premalignant lung changes and lung cancer.
    METHODS: Studies assessing the impact of marijuana smoking on lung premalignant findings and lung cancer were selected from MEDLINE, PSYCHLIT, and EMBASE databases according to the following predefined criteria: English-language studies of persons 18 years or older identified from 1966 to the second week of October 2005 were included if they were research studies (ie, not letters, reviews, editorials, or limited case studies), involved persons who smoked marijuana, and examined premalignant or cancerous changes in the lung.
    RESULTS: Nineteen studies met selection criteria. Studies that examined lung cancer risk factors or premalignant changes in the lung found an association of marijuana smoking with increased tar exposure, alveolar macrophage tumoricidal dysfunction, increased oxidative stress, and bronchial mucosal histopathologic abnormalitiescompared with tobacco smokers or nonsmoking controls. Observational studies of subjects with marijuana exposure failed to demonstrate significant associations between marijuana smoking and lung cancer after adjusting for tobacco use. The primary methodologic deficiencies noted include selection bias, small sample size, limited generalizability, overall young participant age precluding sufficient lag time for lung cancer outcome identification, and lack of adjustment for tobacco smoking.
    CONCLUSION: Given the prevalence of marijuana smoking and studies predominantly supporting biological plausibility of an association of marijuana smoking with lung cancer on the basis of molecular, cellular, and histopathologic findings, physicians should advise patients regarding potential adverse health outcomes until further rigorous studies are performed that permit definitive conclusions.
    ADDepartment of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-6003, USA. [email protected]
    PMID16832000


    37
    PubMed
    TIMarijuana smoking and the risk of head and neck cancer: pooled analysis in the INHANCE consortium.
    AUBerthiller J, Lee YC, Boffetta P, Wei Q, Sturgis EM, Greenland S, Morgenstern H, Zhang ZF, Lazarus P, Muscat J, Chen C, Schwartz SM, Eluf Neto J, Wünsch Filho V, Koifman S, Curado MP, Matos E, Fernandez L, Menezes A, Daudt AW, Ferro G, Brennan P, Hashibe M
    SOCancer Epidemiol Biomarkers Prev. 2009;18(5):1544.

    BACKGROUND: Marijuana contains carcinogens similar to tobacco smoke and has been suggested by relatively small studies to increase the risk of head and neck cancer (HNC). Because tobacco is a major risk factor for HNC, large studies with substantial numbers of never tobacco users could help to clarify whether marijuana smoking is independently associated with HNC risk.
    METHODS: We pooled self-reported interview data on marijuana smoking and known HNC risk factors on 4,029 HNC cases and 5,015 controls from five case-control studies within the INHANCE Consortium. Subanalyses were conducted among never tobacco users (493 cases and 1,813 controls) and among individuals who did not consume alcohol or smoke tobacco (237 cases and 887 controls).
    RESULTS: The risk of HNC was not elevated by ever marijuana smoking [odds ratio (OR), 0.88; 95% confidence intervals (95% CI), 0.67-1.16], and there was no increasing risk associated with increasing frequency, duration, or cumulative consumption of marijuana smoking. An increased risk of HNC associated with marijuana use was not detected among never tobacco users (OR, 0.93; 95% CI, 0.63-1.37; three studies) nor among individuals who did not drink alcohol and smoke tobacco (OR, 1.06; 95% CI, 0.47-2.38; two studies).
    CONCLUSION: Our results are consistent with the notion that infrequent marijuana smoking does not confer a risk of these malignancies. Nonetheless, because the prevalence of frequent marijuana smoking was low in most of the contributing studies, we could not rule out a moderately increased risk, particularly among subgroups without exposure to tobacco and alcohol.
    ADLifestyle, Environment and Cancer Group, IARC, 69008 Lyon, France.
    PMID19423532
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  5. #645
    Ljc
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    devo colocar o resto das evidências científicas ou já poluiu demais o tópico?
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  6. #646
    Table Captain Avatar de Gorizinho
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    Sim, poluiu o topico com várias pesquisas inconclusivas.
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  7. #647
    Ljc
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    Citação Postado originalmente por Gorizinho Ver Post
    Sim, poluiu o topico com várias pesquisas inconclusivas.
    [ ] esse manja


    jovem,

    o que vc chamou de "pesquisas inconclusivas" são os dois maiores artigos de revisão sobre o tema.

    tipo, tudo o que se sabe sobre o tema reunido e condensado
    Última edição por Ljc; 27-03-2012 às 22:42.
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  8. #648
    Ljc
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    (mas talvez a reportagem do Washington post seja melhor)
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  9. #649
    Table Captain Avatar de Gorizinho
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    Citação Postado originalmente por Ljc Ver Post
    BACKGROUND: The association between marijuana smoking and lung cancer is unclear, and a systematic appraisal of this relationship has yet to be performed. Our objective was to assess the impact of marijuana smoking on the development of premalignant lung changes and lung cancer.
    RESULTS: Nineteen studies met selection criteria. Studies that examined lung cancer risk factors or premalignant changes in the lung found an association of marijuana smoking with increased tar exposure, alveolar macrophage tumoricidal dysfunction, increased oxidative stress, and bronchial mucosal histopathologic abnormalitiescompared with tobacco smokers or nonsmoking controls. Observational studies of subjects with marijuana exposure failed to demonstrate significant associations between marijuana smoking and lung cancer after adjusting for tobacco use. The primary methodologic deficiencies noted include selection bias, small sample size, limited generalizability, overall young participant age precluding sufficient lag time for lung cancer outcome identification, and lack of adjustment for tobacco smoking.
    CONCLUSION: Given the prevalence of marijuana smoking and studies predominantly supporting biological plausibility of an association of marijuana smoking with lung cancer on the basis of molecular, cellular, and histopathologic findings, physicians should advise patients regarding potential adverse health outcomes until further rigorous studies are performed that permit definitive conclusions.
    ADDepartment of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-6003, USA. [email protected]
    PMID16832000


    37
    PubMed
    TIMarijuana smoking and the risk of head and neck cancer: pooled analysis in the INHANCE consortium.
    AUBerthiller J, Lee YC, Boffetta P, Wei Q, Sturgis EM, Greenland S, Morgenstern H, Zhang ZF, Lazarus P, Muscat J, Chen C, Schwartz SM, Eluf Neto J, Wünsch Filho V, Koifman S, Curado MP, Matos E, Fernandez L, Menezes A, Daudt AW, Ferro G, Brennan P, Hashibe M
    SOCancer Epidemiol Biomarkers Prev. 2009;18(5):1544.

    BACKGROUND: Marijuana contains carcinogens similar to tobacco smoke and has been suggested by relatively small studies to increase the risk of head and neck cancer (HNC). Because tobacco is a major risk factor for HNC, large studies with substantial numbers of never tobacco users could help to clarify whether marijuana smoking is independently associated with HNC risk.
    METHODS: We pooled self-reported interview data on marijuana smoking and known HNC risk factors on 4,029 HNC cases and 5,015 controls from five case-control studies within the INHANCE Consortium. Subanalyses were conducted among never tobacco users (493 cases and 1,813 controls) and among individuals who did not consume alcohol or smoke tobacco (237 cases and 887 controls).
    RESULTS: The risk of HNC was not elevated by ever marijuana smoking [odds ratio (OR), 0.88; 95% confidence intervals (95% CI), 0.67-1.16], and there was no increasing risk associated with increasing frequency, duration, or cumulative consumption of marijuana smoking. An increased risk of HNC associated with marijuana use was not detected among never tobacco users (OR, 0.93; 95% CI, 0.63-1.37; three studies) nor among individuals who did not drink alcohol and smoke tobacco (OR, 1.06; 95% CI, 0.47-2.38; two studies).
    CONCLUSION: Our results are consistent with the notion that infrequent marijuana smoking does not confer a risk of these malignancies. Nonetheless, because the prevalence of frequent marijuana smoking was low in most of the contributing studies, we could not rule out a moderately increased risk, particularly among subgroups without exposure to tobacco and alcohol.
    ADLifestyle, Environment and Cancer Group, IARC, 69008 Lyon, France.
    PMID19423532
    Pelo menos lê a conclusão das pesquisas antes de postar.
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  10. #650
    Chip Leader Avatar de Ringss
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    o topic ficou tão chato que ate a Amy resolveu acender um lá do céu

    Última edição por Ringss; 27-03-2012 às 23:08.
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