Day-time variation of serum periostin in asthmatic adults treated with ICS/LABA and adults without asthma.

Background: We aimed to determine the effect of sampling time during the day on serum periostin levels in adult participants with and without asthma.

Methods: Serum periostin was measured at 2-h intervals from 0800 to 1800 h in 16 adult participants with stable asthma prescribed inhaled corticosteroid and long-acting beta-agonist therapy, and in 16 otherwise healthy participants without asthma. Mixed linear models were used to compare time zero (08:00 h) with subsequent measurement time for serum periostin for both groups.