title: Cannabis smoking and serum C-reactive protein: a quantile regressions approach based on NHANES 2005-2010.
abstract: BACKGROUND
  Pre-clinical studies link cannabinoid-1 receptor activation to inflammation and atherosclerotic effects; anti-inflammation and immunosuppression seem to be mediated by cannabinoid-2 receptor activation. In this epidemiological study, we aim to present estimates on suspected cannabis-attributable immunomodulation as manifest in serum C-reactive protein (CRP) levels as non-specific inflammatory markers with interpretable clinical values. With strength of data from recent large nationally representative community sample surveys, the research approach illustrates value of a quantile regressions approach in lieu of the commonly used but relatively arbitrary cutpoints for CRP values.
  
  
  METHODS
  The study population encompasses 20-59 year old participants from the National Health and Nutrition Examination Surveys, 2005-2010 (n=1115 recently active cannabis smokers and 8041 non-smokers, identified via confidential Audio Computer Assisted Self-Interviews). Age, sex, race, education, income-poverty ratio, alcohol consumption, and tobacco smoking also were measured, together with body mass index (BMI), which actually might be on a mediational path. Quantile regressions, with bootstrapping for variance estimation, made it possible to hold these covariates constant while estimating cannabis-CRP associations.
  
  
  RESULTS
  Evidence suggesting possible cannabis-attributable immunomodulation emerges at CRP levels below the median (p<0.05). Whereas BMI might help explain a cannabis link with serum CRP, but BMI-stratified analyses disclosed no appreciable variation of the cannabis-CRP relationship across BMI subgroups.
  
  
  CONCLUSIONS
  Extending pre-clinical research on cannabis-attributable immunomodulation, this study's CRP evidence points toward possible anti-inflammatory effects of cannabis smoking. More definitive evidence can be derived by combining pre-clinical research, studies of patients, and epidemiological research approaches.
authors.affiliation: Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI 48823, United States.
authors.forename: Omayma
authors.initials: O
authors.lastname: Alshaarawy
authors.affiliation: Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI 48823, United States. Electronic address: janthony@msu.edu.
authors.forename: James C
authors.initials: JC
authors.lastname: Anthony
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000523:psychology; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000097:blood*; D008875:Middle Aged; D009749:Nutrition Surveys; D012907:Smoking / Q000097:blood; D012959:Socioeconomic Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: CRP; Cannabis smoking; Immunomodulation; Inflammation; NHANES