medwireNews: Research in Hong Kong shows that air pollution concentrations are significantly associated with the number of consultations for upper respiratory tract infections (URTIs), contributing to the burden on primary care services.
The research team, led by Tze Wai Wong (The Chinese University of Hong Kong), analysed data from five public general outpatients clinics that provide state-subsidised primary care for socially disadvantaged individuals.
Between 2008 and 2010, there were 817,240 URTI-related consultations and the mean daily number of consultations ranged from 68.4 to 253.0 across the five practices.
The team found that concentrations of air pollutants, as measured by four monitoring stations near to the practices, were consistently associated with the number of consultations for URTIs. This was true of NO2 in all of the individual clinics, for PM10 (particulate matter diameter <10 µm) in three of the clinics and O3 in four of the clinics.
The summary relative risks across all five clinics showed that each 10 µg/m3 increase in each respective pollutant was associated with a 0.5%, 1.0% and 0.9% increase in the number of URTI-related consultations. There was no significant association between consultations and SO2 levels, but the authors note that levels of this pollutant in Hong Kong were generally within World Health Organization guidelines.
Writing in PLoS One, Wong et al say that their study sheds light on the broader impact of air pollution on respiratory infections.
“Most epidemiological time series studies on air pollution focus on hospital admissions and mortality as health outcomes,” they explain.
“These outcomes represent, respectively, serious morbidity and the ultimate health consequence of air pollution. Illnesses seen in primary health care settings, by contrast, form the much wider base of the ‘pyramid’ of air pollution-related diseases, but are much less studied.”
The authors conclude that the findings provide further evidence that air pollution is a major public health problem that impacts at the primary care level.
“Air pollution thus incurs a substantial burden to health care services in an urban community,” they write.
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