title: The association of health literacy with adherence in older adults, and its role in interventions: a systematic meta-review.
abstract: BACKGROUND
  Low health literacy is a common problem among older adults. It is often suggested to be associated with poor adherence. This suggested association implies a need for effective adherence interventions in low health literate people. However, previous reviews show mixed results on the association between low health literacy and poor adherence. A systematic meta-review of systematic reviews was conducted to study the association between health literacy and adherence in adults above the age of 50. Evidence for the effectiveness of adherence interventions among adults in this age group with low health literacy was also explored.
  
  
  METHODS
  Eight electronic databases (MEDLINE, ERIC, EMBASE, PsycINFO, CINAHL, DARE, the Cochrane Library, and Web of Knowledge) were searched using a variety of keywords regarding health literacy and adherence. Additionally, references of identified articles were checked. Systematic reviews were included if they assessed the association between health literacy and adherence or evaluated the effectiveness of interventions to improve adherence in older adults with low health literacy. The AMSTAR tool was used to assess the quality of the included reviews. The selection procedure, data-extraction, and quality assessment were performed by two independent reviewers. Seventeen reviews were selected for inclusion.
  
  
  RESULTS
  Reviews varied widely in quality. Both reviews of high and low quality found only weak or mixed associations between health literacy and adherence among older adults. Reviews report on seven studies that assess the effectiveness of adherence interventions among low health literate older adults. The results suggest that some adherence interventions are effective for this group. The interventions described in the reviews focused mainly on education and on lowering the health literacy demands of adherence instructions. No conclusions could be drawn about which type of intervention could be most beneficial for this population.
  
  
  CONCLUSIONS
  Evidence on the association between health literacy and adherence in older adults is relatively weak. Adherence interventions are potentially effective for the vulnerable population of older adults with low levels of health literacy, but the evidence on this topic is limited. Further research is needed on the association between health literacy and general health behavior, and on the effectiveness of interventions.
authors.affiliation: Department of Health Sciences, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, FA10, PO Box 196, , 9700 AD, Groningen, The Netherlands. b.j.m.geboers@umcg.nl.
authors.forename: Bas
authors.initials: B
authors.lastname: Geboers
authors.affiliation: Norwich Medical School, Faculty of Medicine & Health Sciences, University of East Anglia, Norwich, UK. j.brainard@uea.ac.uk.
authors.forename: Julii S
authors.initials: JS
authors.lastname: Brainard
authors.affiliation: Norwich Medical School, Faculty of Medicine & Health Sciences, University of East Anglia, Norwich, UK. y.loke@uea.ac.uk.
authors.forename: Yoon K
authors.initials: YK
authors.lastname: Loke
authors.affiliation: Department of Communication and Information Studies, Faculty of Arts, University of Groningen, Groningen, The Netherlands. c.j.m.jansen@rug.nl.
authors.forename: Carel J M
authors.initials: CJ
authors.lastname: Jansen
authors.affiliation: Norwich Medical School, Faculty of Medicine & Health Sciences, University of East Anglia, Norwich, UK. c.salter@uea.ac.uk.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Salter
authors.affiliation: Department of Health Sciences, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, FA10, PO Box 196, , 9700 AD, Groningen, The Netherlands. s.a.reijneveld@umcg.nl.
authors.forename: Sijmen A
authors.initials: SA
authors.lastname: Reijneveld
authors.affiliation: Department of Health Sciences, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, FA10, PO Box 196, , 9700 AD, Groningen, The Netherlands. a.f.de.winter@umcg.nl.
authors.forename: Andrea F
authors.initials: AF
authors.lastname: de Winter
authors.forename: Andrea F
authors.initials: AF
authors.lastname: deWinter
mesh_terms: D000368:Aged; D005260:Female; D015438:Health Behavior; D057220:Health Literacy; D006801:Humans; D008297:Male; D010349:Patient Compliance