Elevated serum melatonin is associated with the nocturnal worsening of asthma

J Allergy Clin Immunol. 2003 Sep;112(3):513-7. doi: 10.1016/s0091-6749(03)01717-2.


Background: Increased airway inflammation at night contributes to the nocturnal worsening of asthma. In vitro studies have shown exogenous melatonin to be pro-inflammatory in asthma, but it is unknown whether endogenous melatonin levels are a controller of airway inflammation in nocturnal asthma.

Objective: Our aim was to determine 24-hour patterns of serum melatonin and their relationship to overnight decline in physiology in subjects with nocturnal asthma, non-nocturnal asthma, and in healthy controls.

Methods: Observational study of pulmonary physiology and melatonin levels in patients with nocturnal asthma (n = 7), non-nocturnal asthma (n = 13), and healthy controls (n = 11). Subjects maintained a constant sleep-wake regimen for 7 days. On day 8, serum melatonin was measured every 2 hours by radioimmunoassay and analyzed by cosinor modeling. The correlation between serum melatonin levels and overnight change in spirometry was evaluated by Spearman's rank correlation analysis.

Results: In subjects with nocturnal asthma, peak melatonin levels were significantly elevated compared with healthy controls (67.6 +/- 5.0 pg/mL versus 53.5 +/- 4.0 pg/mL, P =.03). Melatonin acrophase was delayed in nocturnal asthma (02:54 versus 01:58 in healthy controls, P =.003, and 02:15 in non-nocturnal asthma, P =.01). In subjects with nocturnal asthma, increasing melatonin levels were significantly and inversely correlated with overnight change in FEV(1) (r = -.79, P =.04), a relationship that was not observed in non-nocturnal asthma or healthy controls.

Conclusions: Nocturnal asthma is associated with elevation and phase delay of peak serum melatonin levels. Elevated melatonin levels might contribute to the pathogenesis of nocturnal asthma.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Asthma / blood*
  • Asthma / physiopathology*
  • Case-Control Studies
  • Circadian Rhythm / physiology*
  • Female
  • Forced Expiratory Volume
  • Humans
  • Inflammation / blood
  • Male
  • Melatonin / blood*


  • Melatonin