title: Factors associated to lifestyle and risk of adult onset asthma.
abstract: BACKGROUND
  Asthma prevalence has been increasing especially in developed countries. The change seems to be associated with changes in lifestyle. We have made a prospective study to assess the effect of lifestyle factors, including smoking, educational level, physical activity and obesity on adult onset asthma.
  
  
  METHODS
  A population of 10,597 adult twins, initially free of asthma was followed for 9 years. The main outcome measure was questionnaire-based report of physician diagnosed asthma. Logistic regression was used to estimate the risk of asthma predicted by lifestyle factors, with adjustment for atopy and respiratory symptoms.
  
  
  RESULTS
  Obesity at baseline increased asthma risk (multivariable adjusted OR = 3.00, 95% CI: 1.64-5.50 for those with BMI > or = 30 compared to those with normal weight BMI: 20-24.99). Taller height was associated to lower asthma incidence. Leisure time physical activity had a slightly protective effect on asthma risk among men (P for trend = 0.037) while smoking and education did not have significant effects on the risk of adult onset asthma.
  
  
  CONCLUSIONS
  Obesity was associated to the risk of adult onset asthma, while short height and low leisure time physical activity can be considered as other potential risk factors.
authors.affiliation: Department of Public Health, University of Helsinki, Finland. elisa.huovinen@helsinki.fi
authors.forename: E
authors.initials: E
authors.lastname: Huovinen
authors.forename: J
authors.initials: J
authors.lastname: Kaprio
authors.forename: M
authors.initials: M
authors.lastname: Koskenvuo
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D015992:Body Mass Index; D015331:Cohort Studies; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D011446:Prospective Studies; D012307:Risk Factors