Hay fever in a changing climate: linking an Internet-based diary with environmental data.

Investigating the impact of climate change on human health requires the development of efficient tools that link patient symptoms with changing environmental variables. We developed an internet-based hay fever diary linked to simultaneously recorded pollen load and weather variables in Canberra, Australia over spring 2010. We recruited 42 hay fever sufferers to complete a simple online pollen diary daily over a period of 60 days. In conjunction, daily airborne pollen load was counted and meteorological data collected simultaneously. We focused on the relationships between temperature, rainfall, pollen count and rhinoconjunctivitis symptoms. Pollen load increased after a peak rainfall event until the end of the study. Compliance was high, averaging 79% of days per person. Nasal rhinoconjunctivitis symptoms increased in concert with increasing pollen load, and then remained high. Mucosal itching increased more gradually and strongly coincided with increased daily maximum temperature. Our study successfully demonstrated the feasibility of linking pollen load and climate variables to symptoms of rhinoconjunctivitis in the Australian community. However, a larger study would better explore the nature of associations between these variables. Similar online methods could be used to monitor a range of health responses to our changing environment.