title: Effect of insulating existing houses on health inequality: cluster randomised study in the community.
abstract: OBJECTIVE
  To determine whether insulating existing houses increases indoor temperatures and improves occupants' health and wellbeing.
  
  
  METHODS
  Community based, cluster, single blinded randomised study.
  
  
  METHODS
  Seven low income communities in New Zealand.
  
  
  METHODS
  1350 households containing 4407 participants.
  
  
  METHODS
  Installation of a standard retrofit insulation package.
  
  
  METHODS
  Indoor temperature and relative humidity, energy consumption, self reported health, wheezing, days off school and work, visits to general practitioners, and admissions to hospital.
  
  
  RESULTS
  Insulation was associated with a small increase in bedroom temperatures during the winter (0.5 degrees C) and decreased relative humidity (-2.3%), despite energy consumption in insulated houses being 81% of that in uninsulated houses. Bedroom temperatures were below 10 degrees C for 1.7 fewer hours each day in insulated homes than in uninsulated ones. These changes were associated with reduced odds in the insulated homes of fair or poor self rated health (adjusted odds ratio 0.50, 95% confidence interval 0.38 to 0.68), self reports of wheezing in the past three months (0.57, 0.47 to 0.70), self reports of children taking a day off school (0.49, 0.31 to 0.80), and self reports of adults taking a day off work (0.62, 0.46 to 0.83). Visits to general practitioners were less often reported by occupants of insulated homes (0.73, 0.62 to 0.87). Hospital admissions for respiratory conditions were also reduced (0.53, 0.22 to 1.29), but this reduction was not statistically significant (P=0.16).
  
  
  CONCLUSIONS
  Insulating existing houses led to a significantly warmer, drier indoor environment and resulted in improved self rated health, self reported wheezing, days off school and work, and visits to general practitioners as well as a trend for fewer hospital admissions for respiratory conditions.
authors.affiliation: He Kainga Oranga, Housing and Health Research Programme, University of Otago, Wellington, PO Box 7343, Wellington South, New Zealand.
authors.forename: Philippa
authors.initials: P
authors.lastname: Howden-Chapman
authors.forename: Anna
authors.initials: A
authors.lastname: Matheson
authors.forename: Julian
authors.initials: J
authors.lastname: Crane
authors.forename: Helen
authors.initials: H
authors.lastname: Viggers
authors.forename: Malcolm
authors.initials: M
authors.lastname: Cunningham
authors.forename: Tony
authors.initials: T
authors.lastname: Blakely
authors.forename: Chris
authors.initials: C
authors.lastname: Cunningham
authors.forename: Alistair
authors.initials: A
authors.lastname: Woodward
authors.forename: Kay
authors.initials: K
authors.lastname: Saville-Smith
authors.forename: Des
authors.initials: D
authors.lastname: O'Dea
authors.forename: Martin
authors.initials: M
authors.lastname: Kennedy
authors.forename: Michael
authors.initials: M
authors.lastname: Baker
authors.forename: Nick
authors.initials: N
authors.lastname: Waipara
authors.forename: Ralph
authors.initials: R
authors.lastname: Chapman
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Davie
mesh_terms: D000041:Absenteeism; D000328:Adult; D000704:Analysis of Variance; D016000:Cluster Analysis; D004779:Environment Design; D005194:Family Practice / Q000706:statistics & numerical data; D006304:Health Status; D006361:Heating / Q000706:statistics & numerical data; D006760:Hospitalization / Q000706:statistics & numerical data; D006798:Housing / Q000592:standards*; D006801:Humans; D009520:New Zealand; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data; D011204:Poverty Areas; D018582:Sick Leave / Q000706:statistics & numerical data; D016037:Single-Blind Method; D012959:Socioeconomic Factors; D013696:Temperature