Teenagers who stay up late three times likely to develop asthma as compared to those who sleep early: Study
Researchers also found that the risk of suffering allergic rhinitis was twice as high in late-sleepers compared to early-sleepers
Teenagers who prefer to stay up late and wake up later in the morning are more likely to suffer from asthma and allergies compared to those who sleep and wake earlier. This is according to a new study which says that the chance of having asthma was around three times higher in teens who prefer to sleep later compared to those who prefer to sleep earlier. Researchers also found that the risk of suffering allergic rhinitis was twice as high in late-sleepers compared to early-sleepers. Also known as hay fever, allergic rhinitis is a group of symptoms affecting the nose, and occurs when the body’s immune system recognizes and overreacts to something in the environment. Asthma symptoms are known to be strongly linked to the body's internal clock, but earlier studies have not looked at how individual sleep preferences influence asthma risk in teenagers. The latest findings reinforce the importance of sleep timing for teenagers and open up a new channel of research into how sleep affects teenagers' respiratory health, says the research team from Spain and India.
“Asthma and allergic diseases are common in children and adolescents across the world and the prevalence is increasing. We know some of the reasons for this increase, such as exposure to pollution and tobacco smoke, but we still need to find out more. Sleep and the 'sleep hormone' melatonin are known to influence asthma, so we wanted to see if adolescents' preference for staying up late or going to bed early could be involved in their asthma risk,” says Dr Subhabrata Moitra from the division of pulmonary medicine at the University of Alberta, Canada, in the report published in ERJ Open Research. He conducted the research while at the Barcelona Institute for Global Health, Spain. According to the US Centers for Disease Control and Prevention (CDC), 24,753,379 Americans had asthma in 2018. This is 7.5% of children (5,530,131 children below the age of 19) and 7.7% of adults (19,223,248 over 18 years of age).
The current study involved 1,684 adolescents living in India, aged 13 or 14 years, who were participating in the Prevalence and Risk Factors of Asthma and Allergy-Related Diseases among Adolescents (PERFORMANCE) study. Each participant was asked about any wheezing, asthma, or symptoms of allergic rhinitis, such as a runny nose and sneezing. They were asked a series of questions to judge whether they were “evening types,” “morning types,” or in between, such as what time of the evening or night they tend to feel tired, when they would choose to wake up, and how tired they feel first thing in the morning. Researchers compared the teenagers' symptoms with their sleep preferences, taking into account other factors that are known to affect asthma and allergies, such as where the participants live and whether their family members smoke.
An estimated 42% of the participants were girls. 42% and 9% of the participants were identified as morning and evening types, respectively, while the rest (49%) were intermediate types. “This is the first study to report on the possible association between chronotype and respiratory symptoms among adolescents. Compared to the morning-type individuals, those that were evening type had a higher risk of current (but not ever) wheeze (6.4% versus 11.7%). A similar result was observed for participants reporting ever or current rhinitis, but additionally, those that were intermediate type also demonstrated significantly higher risks than the morning type. Rhinoconjunctivitis was also higher in the intermediate-type (relative risk 1.51) and evening-type groups (relative risk 2.76) compared to those in the morning-type group. The relative risk for asthma was three times higher among the evening-type participants (6.2% versus 23.6%) than the morning types,” the findings state.
According to Dr Moitra, these results suggest that there is a link between preferred sleep time, and asthma and allergies in teenagers. “We can't be certain that staying up late is causing asthma, but we know that the sleep hormone melatonin is often out of sync in late-sleepers and that could, in turn, be influencing teenagers' allergic response,” says Dr Moitra. He adds, “We also know that children and young people are increasingly exposed to the light from mobile phones, tablets, and other devices, and staying up later at night. It could be that encouraging teenagers to put down their devices and get to bed a little earlier would help decrease the risk of asthma and allergies. That's something that we need to study more.”
A second phase of the study is scheduled in 2028-29, which means it will be possible to repeat the study with a new group of teenagers to see if there has been any change in teenagers sleeping habits and their respiratory health. The research team also hopes to quantify their findings by taking objective measurements of participants' lung function and sleep time. “We need to know much more about why asthma and allergies are rising in children and teenagers and, hopefully, find ways to reduce these conditions. This is the first study to examine the possible role of different sleep preferences in teenagers' risk of asthma and allergies, and it opens up an interesting and important new line of research. We already know that sleeping well is important for physical and mental health, so we should continue to encourage teenagers to get a good night's sleep,” says Professor Thierry Troosters, president of the European Respiratory Society, who was not involved in the research.