title: Social inequality in motorcycle helmet use: when a reduction in inequality is not necessarily good news.
abstract: BACKGROUND
  We sought to examine changes in the magnitude of social inequality in motorcycle helmet use in Taiwan between 2001 and 2009.
  
  
  METHODS
  Using data from the 2001 and 2009 Taiwan National Health Interview Surveys, we calculated absolute (the slope index of inequality, SII) and relative (relative index of inequality, RII) measures of inequality in helmet use by three indicators of socioeconomic position.
  
  
  RESULTS
  The rate of motorcycle helmet use was 92% (14 801/16 100) in 2001 and decreased to 89% (15 748/17 948) in 2009. We noted a significant decrease in social inequality in helmet use in RII according to urbanisation level, a significant decrease in SII and RII according to income level, and a significant increase in SII according to education level. The reduction in RII according to urbanisation level was more prominent than that based on income level, from 1.73 (95% CI 1.63 to 1.84) in 2001 to 1.33 (95% CI 1.27 to 1.39) in 2009. The decline in helmet use was most prominent for motorcycle users who live in suburban areas, from 94% in 2001 to 88% in 2009.
  
  
  CONCLUSIONS
  The significant reduction of social inequality in helmet use according to urbanisation level and income is not a public health success story. Rather, it is a warning sign of slackening law enforcement in Taiwan.
authors.affiliation: Health Promotion Administration, Ministry of Health and Welfare, Taipei, Taiwan Institute of Public Health, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Shu-Ti
authors.initials: ST
authors.lastname: Chiou
authors.affiliation: Department of Public Health, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Tsung-Hsueh
authors.initials: TH
authors.lastname: Lu
authors.affiliation: Safety Division, Institute of Transportation, Ministry of Transportation and Communications, Taipei, Taiwan.
authors.forename: Ching-Huei
authors.initials: CH
authors.lastname: Lai
authors.affiliation: Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei, Taiwan.
authors.forename: Tung-Liang
authors.initials: TL
authors.lastname: Chiang
authors.affiliation: Department of Social & Behavioral Sciences, Harvard School of Public Health, Harvard University, Boston, USA.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawachi
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006260:Head Protective Devices / Q000706:statistics & numerical data*; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D036301:Qualitative Research; D013624:Taiwan; D014507:Urbanization; D055815:Young Adult
keywords: Health Behaviour; Injury; Social Inequalities