Hormone May Worsen Nighttime Asthma
Individuals with nocturnal asthma need to worry about melatonin, a naturally occurring hormone that helps regulate the body's circadian rhythms. So suggest the results of a study published in the Journal of Allergy and Clinical Immunology (September 2003). Participants in the study included 7 with nocturnal asthma, 13 with nonnocturnal asthma, and 11 without asthma. While the participants slept, the researchers took blood samples from them every 2 hours. The investigators also measured lung function before the patients went to bed and again after they woke up. The results showed that the patients with nocturnal asthma had the highest levels of melatonin and the biggest drop in lung function. Among those with nocturnal asthma, levels of melatonin were an average of 68 pg/mL, compared with 61 pg/mL for patients with nonnocturnal asthma and 54 pg/mL for patients without asthma. Lung function dropped by an average of 19% in nocturnal asthma patients, compared with 5% in patients with nonnocturnal asthma. In nonasthma patients, lung function increased by ~2%. "These findings raise concern that high melatonin levels may play a role in making asthma worse at night, and therefore people with asthma should avoid taking supplemental melatonin," advised study author Rand Sutherland, MD, an assistant professor of medicine at the National Jewish Medical Center in Denver.