title: Associations of cigarette smoking, betel quid chewing and alcohol consumption with high-sensitivity C-reactive protein in early radiographic knee osteoarthritis: a cross-sectional study.
abstract: OBJECTIVE
  High-sensitivity C-reactive protein (hsCRP) is possibly related to osteoarthritis (OA) progression and a variety of OA-related symptoms. This study aimed to examine associations between cigarette smoking, betel quid chewing and alcohol consumption and hsCRP in early radiographic knee OA.
  
  
  METHODS
  Cross-sectional health examination survey.
  
  
  METHODS
  This primary study was conducted in a health examination centre in China.
  
  
  METHODS
  936 (656 men and 280 women) patients with early radiographic knee OA were included in this cross-sectional study.
  
  
  METHODS
  Smoking status was classified into four levels based on daily smoking habit: 0/day, 1-10/day, 11-20/day and >20/day. Betel quid chewing and alcohol consumption status was divided into 'Yes' or 'No'. Early radiographic knee OA was defined as Kellgren Lawrence (K-L) grade 1 or 2 in at least one leg, and elevated hsCRP was assessed as ≥ 3.0 mg/L.
  
  
  RESULTS
  After adjustment for a number of potential confounding factors, a significant positive association between cigarette smoking and hsCRP was observed in the multivariable model. The multivariable-adjusted ORs (95% CI) of elevated hsCRP (≥ 3.0 mg/L) in the second (1-10/day, n=133), third (11-20/day, n=59) and highest (>20/day, n=104) cigarette smoking categories were 1.54 (95% CI 0.91 to 2.61), 1.27 (95% CI 0.57 to 2.79) and 2.09 (95% CI 1.20 to 3.64), respectively, compared with the non-smoker category (n=640). In addition, there was a positive dose-response relationship between cigarette smoking and elevated hsCRP (p for trend=0.01). No significant associations between betel quid chewing and alcohol consumption and hsCRP were observed in the multivariable model.
  
  
  CONCLUSIONS
  This study indicated that cigarette smoking was positively associated with serum hsCRP level in patients with early radiographic knee OA. However, in view of the nature of cross-sectional designs, the results need to be confirmed by further prospective studies.
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zeng
authors.affiliation: Health Management Center, Xiangya Hospital, Central South University, Changsha, Hunan Province, China Department of Epidemiology and Health Statistics, School of Public Health, Central South University, Changsha, Hunan Province, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wei
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Tuo
authors.initials: T
authors.lastname: Yang
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Zhen-han
authors.initials: ZH
authors.lastname: Deng
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Ding
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
authors.forename: Guanghua
authors.initials: G
authors.lastname: Lei
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000453:epidemiology*; D001114:Areca / Q000009:adverse effects*; D002097:C-Reactive Protein / Q000032:analysis*; D002681:China; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008409:Mastication; D008875:Middle Aged; D015999:Multivariate Analysis; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging*; D011859:Radiography; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*
chemical_list: D002097:C-Reactive Protein
keywords: C-reactive protein; alcohol drinking; betel quilt chewing; cigarette smoking; osteoarthritis