title: Prevalence, risk factors and associations of primary Raynaud's phenomenon: systematic review and meta-analysis of observational studies.
abstract: OBJECTIVE
  To systematically review the literature with regard to the prevalence, incidence, risk factors and associations of primary Raynaud's phenomenon (PRP).
  
  
  METHODS
  A systematic review of the literature of observational studies for PRP was undertaken using five electronic databases. Any studies reporting prevalence, incidence and risk factors of PRP were collected. Relative risk or OR and 95% CI were extracted or calculated to present the association between risk factors and PRP. Random effects model was used to pool the results.
  
  
  RESULTS
  33 articles assessing a total of 33,733 participants were included in this analysis (2 cohort, 17 cross-sectional and 14 case-control studies). The pooled prevalence of PRP was 4.85% (95% CI 2.08% to 8.71%) in the general population. The pooled annual incidence of PRP was 0.25% (95% CI 0.19% to 0.32%). Risk factors and associations for PRP included female gender (OR=1.65, 95% CI 1.42 to 1.91), family history (OR=16.6, 95% CI 7.44 to 36.8), smoking (OR=1.27, 95% CI 1.06 to 1.53), manual occupation (OR=2.66 95% CI 1.73 to 4.08), migraine (OR=4.02, 95% CI 2.62 to 6.17), cardiovascular disease (OR=1.69, 95% CI 1.22 to 2.34) and marital status (married, OR=0.60, 95% CI 0.43 to 0.83). The definition of PRP varied considerably between studies.
  
  
  CONCLUSIONS
  This is the first systematic review of the prevalence, incidence, risk factors and associations of PRP. Further study using uniform strict criteria for the condition is required to confirm these findings, particularly the possible association with cardiovascular disease.
authors.affiliation: Department of Rheumatology, Queens Medical Centre, Nottingham, UK.
authors.forename: Rozeena
authors.initials: R
authors.lastname: Garner
authors.affiliation: Department of Rheumatology, Queens Medical Centre, Nottingham, UK.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kumari
authors.affiliation: Department of Rheumatology, Queens Medical Centre, Nottingham, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Lanyon
authors.affiliation: Department of Rheumatology, Queens Medical Centre, Nottingham, UK Department of Academic Rheumatology, University of Nottingham, Nottingham, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Doherty
authors.affiliation: Department of Academic Rheumatology, University of Nottingham, Nottingham, UK.
authors.forename: Weiya
authors.initials: W
authors.lastname: Zhang
mesh_terms: D003080:Cold Temperature; D006801:Humans; D064887:Observational Studies as Topic; D015995:Prevalence; D011928:Raynaud Disease / Q000150:complications / Q000453:epidemiology*; D012307:Risk Factors
keywords: EPIDEMIOLOGY; RHEUMATOLOGY; STATISTICS & RESEARCH METHODS