title: The impact of health literacy and life style risk factors on health-related quality of life of Australian patients.
abstract: BACKGROUND
  Limited evidence exists regarding the relationship between health literacy and health-related quality of life (HRQoL) in Australian patients from primary care. The objective of this study was to investigate the impact of health literacy on HRQoL in a large sample of patients without known vascular disease or diabetes and to examine whether the difference in HRQoL between low and high health literacy groups was clinically significant.
  
  
  METHODS
  This was a cross-sectional study of baseline data from a cluster randomised trial. The study included 739 patients from 30 general practices across four Australian states conducted in 2012 and 2013 using the standard Short Form Health Survey (SF-12) version 2. SF-12 physical component score (PCS-12) and mental component score (MCS-12) are derived using the standard US algorithm. Health literacy was measured using the Health Literacy Management Scale (HeLMS). Multilevel regression analysis (patients at level 1 and general practices at level 2) was applied to relate PCS-12 and MCS-12 to patient reported life style risk behaviours including health literacy and demographic factors.
  
  
  RESULTS
  Low health literacy patients were more likely to be smokers (12 % vs 6 %, P = 0.005), do insufficient physical activity (63 % vs 47 %, P < 0.001), be overweight (68 % vs 52 %, P < 0.001), and have lower physical health and lower mental health with large clinically significant effect sizes of 0.56 (B (regression coefficient) = -5.4, P < 0.001) and 0.78(B = -6.4, P < 0.001) respectively after adjustment for confounding factors. Patients with insufficient physical activity were likely to have a lower physical health score (effect size = 0.42, B = -3.1, P < 0.001) and lower mental health (effect size = 0.37, B = -2.6, P < 0.001). Being overweight tended to be related to a lower PCS-12 (effect size = 0.41, B = -1.8, P < 0.05). Less well-educated, unemployed and smoking patients with low health literacy reported worse physical health. Health literacy accounted for 45 and 70 % of the total between patient variance explained in PCS-12 and MCS-12 respectively.
  
  
  CONCLUSIONS
  Addressing health literacy related barriers to preventive care may help reduce some of the disparities in HRQoL. Recognising and tailoring health related communication to those with low health literacy may improve health outcomes including HRQoL in general practice.
authors.affiliation: Centre for Primary Health Care and Equity, Level 3 AGSM, University of New South Wales Australia, Sydney, NSW, 2052, Australia. upali.jay@unsw.edu.au.
authors.forename: Upali W
authors.initials: UW
authors.lastname: Jayasinghe
authors.affiliation: Centre for Primary Health Care and Equity, Level 3 AGSM, University of New South Wales Australia, Sydney, NSW, 2052, Australia.
authors.forename: Mark Fort
authors.initials: MF
authors.lastname: Harris
authors.affiliation: Centre for Primary Health Care and Equity, Level 3 AGSM, University of New South Wales Australia, Sydney, NSW, 2052, Australia.
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Parker
authors.affiliation: Discipline of General Pratice, School of Medicine, Flinders University, Adelaide, South Australia, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Litt
authors.affiliation: Discipline of General Practice, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Mieke
authors.initials: M
authors.lastname: van Driel
authors.affiliation: Department of General Practice, Monash University, Notting Hill, VIC, Australia.
authors.forename: Danielle
authors.initials: D
authors.lastname: Mazza
authors.affiliation: Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Del Mar
authors.affiliation: Centre for Primary Health Care and Equity, Level 3 AGSM, University of New South Wales Australia, Sydney, NSW, 2052, Australia.
authors.forename: Jane
authors.initials: J
authors.lastname: Lloyd
authors.affiliation: Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia.
authors.forename: Jane
authors.initials: J
authors.lastname: Smith
authors.affiliation: School of Public Health and Community Medicine, University of New South Wales Australia, Sydney, NSW, Australia.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Zwar
authors.affiliation: School of Public Health and Community Medicine, University of New South Wales Australia, Sydney, NSW, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Taylor
mesh_terms: D000328:Adult; D000368:Aged; D001294:Attitude to Health; D001315:Australia; D003430:Cross-Sectional Studies; D005260:Female; D057220:Health Literacy; D006306:Health Surveys; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D010361:Patients / Q000523:psychology*; D011788:Quality of Life / Q000523:psychology*; D012307:Risk Factors; D012959:Socioeconomic Factors
keywords: Health literacy; Life style risk factors; Mental component score; Multilevel regression analysis; Physical component score; Quality of life; SF-12 version 2