A recent study conducted by researchers at the University of Cambridge has shed light on the reliability of a lung function test used to diagnose asthma. The study found that the test works better in the morning and is less reliable as the day progresses. Additionally, the researchers discovered that the test’s reliability varies between seasons, with winter showing more accurate results compared to autumn.
Asthma is a common lung condition that affects approximately 6.5% of people over the age of six in the UK. It can cause symptoms such as wheezing and shortness of breath, with treatments typically involving inhalers or nebulizers to deliver medication to the lungs. The majority of asthma attacks occur at night or in the early morning, suggesting a possible link to circadian rhythms.
The study, conducted at the Victor Phillip Dahdaleh Heart and Lung Research Institute in collaboration with the Royal Papworth Hospital NHS Foundation Trust, aimed to investigate how circadian rhythms may impact the diagnosis of asthma using a standard spirometry test. This test involves measuring lung function by having the patient take a deep breath and exhale forcefully into a tube.
The researchers analyzed data from 1,600 patients using the Electronic Patient Record Research and Innovation (ERIN) database, a resource created by the Cambridge University Hospitals NHS Foundation Trust. The results, published in the journal Thorax, revealed that the test’s reliability decreased by 8% for every hour after 8:30 am during the working day.
Lead Research Respiratory Physiologist, Dr. Ben Knox-Brown, emphasized the importance of conducting the test in the morning for more accurate results in diagnosing asthma. He highlighted the significant impact of time of day on the test’s outcomes and the implications for confirming a diagnosis.
Furthermore, the study found that individuals were 33% less likely to have a positive result during autumn compared to winter. Dr. Akhilesh Jha, a Medical Research Council Clinician Scientist at the University of Cambridge, suggested that natural body rhythms and hormonal fluctuations throughout the day may influence test results.
The researchers concluded that factors like time of day and season should be considered when interpreting the results of lung function tests for asthma diagnosis. The study adds to the growing body of evidence suggesting that our health and response to treatments may be influenced by circadian rhythms and seasonal variations.
For more information, the study titled “Effect of time of day and seasonal variation on bronchodilator responsiveness: the SPIRO-TIMETRY study” can be found in the journal Thorax. This research sheds light on the importance of timing in clinical testing and the implications for diagnosing respiratory conditions like asthma.
