Associations between exposure to ambient photochemical oxidants and the vitality or mental health domain of the health related quality of life

Background: Ambient air pollution may affect the health related quality of life (HRQOL) of people, as assessed by the vitality (VT) and mental health (MH) domains of the SF-36 health survey (SF-36). Methods: In a nationwide survey, 4500 people aged 20 years and older were selected from the entire population of Japan by stratified random sampling in October 2002. A total of 2896 subjects filled out the self administered questionnaire that included the SF-36 and demographic characteristics. Data were linked from the questionnaires with the data on air pollutants in the cities where the subjects resided. The paper examined the relations between the mean concentration of each air pollutant and the VT or MH score on the SF-36 using analysis of covariance. Results: On crude analysis, the respondents who were exposed to a higher mean two month concentration of photochemical oxidants (Ox) showed a significant linear trend toward lower VT score (p = 0.028). This association remained even after adjustment for subjective demographic characteristics and meteorological variables (p = 0.033). There was a common tendency that subjects who were exposed to higher concentrations of Ox had a lower mean VT or MH score; however, there was a significant association only between Ox concentration and VT score. Conclusion: The score on the VT domain of the SF-36 was associated with the mean concentration of Ox during the previous two month period. Assessing the health effects of air pollution by measuring the HRQOL, such as by using the SF-36, may provide a new method of formulating air pollution policies.