title: Socioeconomic inequalities in non-communicable diseases and their risk factors: an overview of systematic reviews.
abstract: BACKGROUND
  Non-communicable diseases (NCDs) are the largest cause of premature death worldwide. Socioeconomic inequalities contribute to a disparity in the burden of NCDs among disadvantaged and advantaged populations in low (LIC), middle (MIC), and high income countries (HIC). We conducted an overview of systematic reviews to systematically and objectively assess the available evidence on socioeconomic inequalities in relation to morbidity and mortality of NCDs and their risk factors.
  
  
  METHODS
  We searched PubMed, The Cochrane Library, EMBASE, SCOPUS, Global Health, and Business Source Complete for relevant systematic reviews published between 2003 and December 2013. Two authors independently screened abstracts and full-text publications and determined the risk of bias of the included systematic reviews.
  
  
  RESULTS
  We screened 3302 abstracts, 173 full-text publications and ultimately included 22 systematic reviews. Most reviews had major methodological shortcomings; however, our synthesis showed that having low socioeconomic status (SES) and/or living in low and middle income countries (LMIC) increased the risk of developing cardiovascular diseases (CVD), lung and gastric cancer, type 2 diabetes, and chronic obstructive pulmonary disease (COPD). Furthermore, low SES increased the risk of mortality from lung cancer, COPD, and reduced breast cancer survival in HIC. Reviews included here indicated that lower SES is a risk factor for obesity in HIC, but this association varied by SES measure. Early case fatalities of stroke were lower and survival of retinoblastoma was higher in MIC compared to LIC.
  
  
  CONCLUSIONS
  The current evidence supports an association between socioeconomic inequalities and NCDs and risk factors for NCDs. However, this evidence is incomplete and limited by the fairly low methodological quality of the systematic reviews, including shortcomings in the study selection and quality assessment process.
authors.affiliation: Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria. isolde.sommer@donau-uni.ac.at.
authors.forename: Isolde
authors.initials: I
authors.lastname: Sommer
authors.affiliation: Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria. ursula.griebler@donau-uni.ac.at.
authors.forename: Ursula
authors.initials: U
authors.lastname: Griebler
authors.affiliation: Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria. peter.mahlknecht@donau-uni.ac.at.
authors.forename: Peter
authors.initials: P
authors.lastname: Mahlknecht
authors.affiliation: Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria. kylie.thaler@donau-uni.ac.at.
authors.forename: Kylie
authors.initials: K
authors.lastname: Thaler
authors.affiliation: Department of Anthropology, Emory University, 201 Dowman Drive, Atlanta, Georgia, 30322, USA. kbouski@emory.edu.|Rollins School of Public Health, Emory University, 1518 Clifton Road Northeast, Atlanta, GA, 30322, USA. kbouski@emory.edu.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Bouskill
authors.affiliation: Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria. gerald.gartlehner@donau-uni.ac.at.|RTI International, Research Triangle Park, 3040 East Cornwallis Road, Durham, NC, USA. gerald.gartlehner@donau-uni.ac.at.
authors.forename: Gerald
authors.initials: G
authors.lastname: Gartlehner
authors.affiliation: Chronic Disease Prevention and Management, World Health Organization, 20 Avenue Appia, Geneva, 1211, Switzerland. mendiss@who.int.
authors.forename: Shanti
authors.initials: S
authors.lastname: Mendis
mesh_terms: D002318:Cardiovascular Diseases / Q000209:etiology*; D003906:Developing Countries; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology*; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D009369:Neoplasms / Q000209:etiology* / Q000401:mortality; D009765:Obesity / Q000209:etiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology; D012307:Risk Factors; D012923:Social Class; D012959:Socioeconomic Factors