title: Societal-level Risk Factors Associated with Pediatric Hearing Loss: A Systematic Review.
abstract: To determine if the current body of evidence describes specific threshold values of concern for modifiable societal-level risk factors for pediatric hearing loss, with the overarching goal of providing actionable guidance for the prevention and screening of audiological deficits in children.
  
  
  
  Three related systematic reviews were performed. Computerized PubMed, Embase, and Cochrane Library searches were performed from inception through October 2013 and were supplemented with manual searches.
  
  
  
  Inclusion/exclusion criteria were designed to determine specific threshold values of societal-level risk factors on hearing loss in the pediatric population. Searches and data extraction were performed by independent reviewers.
  
  
  
  There were 20 criterion-meeting studies with 29,128 participants. Infants less than 2 standard deviations below standardized weight, length, or body mass index were at increased risk. Specific nutritional deficiencies related to iodine and thiamine may also increase risk, although data are limited and threshold values of concern have not been quantified. Blood lead levels above 10 µg/dL were significantly associated with pediatric sensorineural loss, and mixed findings were noted for other heavy metals. Hearing loss was also more prevalent among children of socioeconomically disadvantaged families, as measured by a poverty income ratio less than 0.3 to 1, higher deprivation category status, and head of household employment as a manual laborer.
  
  
  
  Increasing our understanding of specific thresholds of risk associated with causative factors forms the foundation for preventive and targeted screening programs as well as future research endeavors.
authors.affiliation: Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Adam P
authors.initials: AP
authors.lastname: Vasconcellos
authors.affiliation: Princeton University, Princeton, New Jersey, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Colello
authors.affiliation: Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Meghann E
authors.initials: ME
authors.lastname: Kyle
authors.affiliation: Harvard Medical School, Boston, Massachusetts, USA jennifer_shin@meei.harvard.edu.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Shin
mesh_terms: D002648:Child; D019317:Evidence-Based Medicine; D014943:Global Health; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D006801:Humans; D007854:Lead / Q000009:adverse effects*; D009752:Nutritional Status; D011203:Poverty; D015995:Prevalence; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D007854:Lead
keywords: adolescent; child; hearing loss; infant; pediatric; risk factor