Variation in lung functions and airway inflammatory markers of asthmatics during menstrual cycle

Abstract

Background/objective: Sex hormones are known to play a role in the pathogenesis of asthma but the mechanisms proposed are inconclusive. We aimed to assess lung function and airway inflammatory markers; Exhaled breath Nitric oxide(FeNO) and blood eosinophil count(EC) at three points of menstrual cycle in stable asthmatics. Method: Asthmatics(n=26) with regular menstrual cycles were recruited after informed consent. Lung function variables FEV1, FVC, PEF, FeNO and EC were measured during menstruation(Day1-3), follicular (Day7-9) and luteal phases ( Day 21-23). Result: Mean age of asthmatics was 22.38(±1.44)years. Mean FEV1 was highest in follicular phase (2.305±.3018)L and lowest in luteal phase (2.2904±.308)L. Highest mean FVC(2.76±.43)L and PEF(5.97±.83)L/s were during menstrual phase while lowest FVC(2.65±.37)L and PEF(5.90s±.89)L/s were during luteal phase. Mean FeNO level and EC was highest in luteal phase (42.19±36.8)ppb and (0.40 ±.258)x109/L. The lowest were obtained in follicular phase (34.77±25.67)ppb and (0.33±.15)x109/L. FeNO level correlated positively with EC in menstrual(r=.540, p=0.004) follicular(r=.466, p=0.016) and luteal(r=.607, p=0.001)phases. FeNO correlated negatively with PEF in follicular and luteal phases and with FEV1 during all three phases. However the variation in lung function variables, FeNO levels and EC was not significant through the phases of menstrual cycle. Conclusion: Changes in PEF, FEV1, FEV1% follow a distinct pattern through the menstrual cycle. FeNO levels and EC changes are parallel in the three phases of menstrual cycle. Changes in lung function and the inflammatory markers observed could be due to the variation in sex hormones.