Significant variations in respiratory symptoms during different stages of the menstrual cycle were identified in a study of almost 4,000 women in Northern Europe, with patterns that varied by body mass index, asthma, and smoking status.
"The findings suggest substantial hormonal influences in interplay with metabolic factors on airway physiology and on pathophysiological processes in respiratory diseases like asthma," concluded Dr. Ferenc Macsali, of the department of gynecology and obstetrics at Haukeland University Hospital, Bergen, Norway, and his associates. The study was published online in November (Am. J. Respir. Crit. Care Med. 2012 [doi: 10.1164/rccm.201206-1112OC]).
The study obtained information from questionnaires mailed to the Nordic-Baltic population of women, with questions about respiratory symptoms, menstrual symptoms, BMI, and smoking status, from 3,926 women (mean age 39 years), with regular cycles no greater than 28 days, who were not on any hormonal medications. The study is part of Respiratory Health in Northern Europe (RHINE), a population-based multicenter questionnaire study. Almost 29% of the women were regular smokers, almost 8% said they had been diagnosed with asthma, and their mean BMI was 23 kg/m2.
Based on their analysis of the responses, the investigators identified significant variations during the menstrual cycle for each of the three symptoms analyzed – wheezing, shortness of breath, and coughing – including reports of wheezing that were higher during cycle days 10-22, with a "dramatic" drop in the middle of the cycle at about days 14-16, the "putative time of ovulation," in most subgroups. Wheezing was lower before and after menses. The daily incidence of shortness of breath was highest on days 7-21, dropping just before the middle of the cycle "in a number of subgroups." And there were peaks in the incidence of cough before and after midcycle, around the time of "putative" ovulation, and before the onset of menses; the incidence of coughs was lower after menses..
The effects of the menstrual cycle on respiratory symptoms in the general female population have not been well studied, and "our finding that respiratory symptoms vary according to the stage of the menstrual cycle is novel, as is our finding that these patterns vary according to BMI and smoking status," Dr. Macsali said in a statement issued by the American Thoracic Society, which publishes the American Journal of Respiratory and Critical Care Medicine.
"These relationships indicate a link between respiratory symptoms and hormonal changes through the menstrual cycle," he added.
"Our results point to the potential for individualizing therapy for respiratory diseases according to individual symptom patterns," Dr. Macsali said in the statement. As an example, he noted, adjusting asthma medication "according to a woman’s menstrual cycle might improve its efficacy and help reduce disability and the costs of care."
The authors acknowledged that the use of the questionnaire to obtain the data, as well as variations in the length of the menstrual cycle among those who responded, were limitations of the study.
No author disclosures were listed in the study. RHINE receives financial support from organizations that include the Swedish Heart and Lung Foundation, the Norwegian Asthma and Allergy Association, and the Danish Lung Association, according to the RHINE website.