Hay fever prevalence in the UK in 2020, 2040 and 2060

Research report by Prof Jean Emberlin

June 11th 2009

The UK has one of the highest prevalence rates for hayfever in the world. The reasons for this are unclear but several possibilities have been suggested including the hygiene hypothesis, air pollution, use of antibiotics and diet. Hayfever affects about 20‐28% of the UK population as a whole, rising to 38% in teenagers. Typical symptoms include frequent sneezing, runny nose and eyes, itchy eyes, throat and mouth and blocked nose.

These can range in severity from being mildly inconvenient to being completely debilitating so the sufferer cannot go about their normal life. If hayfever is not treated to control the symptoms it can develop into asthma. Hayfever imposes a huge socio‐economic cost through time off work or education, demand for healthcare or purchase of medications and treatments. It also has detrimental effects on exam performance, careers and social life and it can lead to a general decrease in quality of life. The prevalence of hayfever in the UK increased dramatically between about 1960 and 2000 after which the increase slowed down to less than 1% per year. However this is still significant due to the high prevalence rate.

In the UK grass pollen (late May to early August) is the main culprit in triggering hayfever symptoms as about 95% of sufferers are allergic to this pollen. Tree pollen can cause problems in the spring and early summer especially birch pollen (late March to mid May) which affects about 25% of sufferers and oak pollen (May which effects about 20% of sufferers). Pollen from weeds can be important from mid summer through to mid autumn, with about 20 % of hayfever sufferers reacting to pollens from weeds such as nettles, docks and plantains. The timing and severity of all these pollen seasons will vary slightly from year to year depending on the weather. The seasons have also been changing over the last few decades due to shifts in weather patterns that could be linked to climate change. Some seasons, such as birch pollen, are now starting up to a month earlier than they were a few decades ago due to warmer weather in winters and springs. Grass and weed pollen season are lasting several weeks longer. Grass pollen seasons were tending to become milder until about 1994 but since then there has been a marked trend towards increasing severity which can be linked to weather changes.

This report explores the likely increases in the prevalence of hayfever in the UK over the next few decades, focussing on changes from 2010 to 2020, 2040 and 2060. It discusses the factors that will drive the changes and examines the impacts of these on prevalence rates in various regions.

The full report can be downloaded at www.lloydspharmacy.com/allergy