Absolute lung size and the sex difference in breathlessness in the general population

Abstract

BackgroundBreathlessness is associated with major adverse health outcomes and is twice as common in women as men in the general population. We evaluated whether this is related to their lower absolute lung volumes.MethodsCross-sectional analysis of the population-based Swedish CardioPulmonarybioImage Study (SCAPIS) Pilot, including static spirometry and diffusing capacity (n = 1,013; 49% women). Breathlessness was measured using the modified Medical Research Council (mMRC) scale and analyzed using ordinal logistic regression adjusting for age, pack-years of smoking, body mass index, chronic airway limitation, asthma, chronic bronchitis, depression and anxiety in all models.ResultsBreathlessness was twice as common in women as in men; adjusted odds ratio (OR) 2.20 (95% confidence interval, 1.32−3.66). Lower absolute lung volumes were associated with increased breathlessness prevalence in both men and women. The sex difference in breathlessness was unchanged when adjusting for lung function in %predicted, but disappeared when controlling for absolute values of total lung capacity (OR 1.12; 0.59−2.15), inspiratory capacity (OR 1.26; 0.68−2.35), forced vital capacity (OR 0.84; 0.42−1.66), forced expiratory volume in one second (OR 0.70; 0.36−1.35) or lung diffusing capacity (OR 1.07; 0.58−1.97).ConclusionIn the general population, the markedly higher prevalence of breathlessness in women is related to their smaller absolute lung volumes.

Correlates of resting and exertional dyspnea among older adults with obstructive lung disease: a cross-sectional analysis of the Canadian Longitudinal Study on Aging

“…Others: Our finding that body fat percentage was associated with exertional dyspnea outcomes is consistent with previous literature that indicates that fat free mass index is correlated with dyspnea among COPD patients 44 , and that body mass index has is associated with dyspnea among adults 40 years and older 3, 4, 45 . It is important to note that higher levels of exertional dyspnea among individuals with more body fat may be related to reduced lung volumes and greater work of breathing required 45 ; however, body mass index is often lower in individuals with the most severe COPD, (GOLD stages 3 and 4) 46 .…”

“…The presence of heart disease was associated with dyspnea in females, such that having heart disease was associated with higher odds of reporting dyspnea at rest and while walking uphill 3 . However, among males, only dyspnea at rest was associated with heart disease, and this association was in the opposite direction expected.…”

“…Each of the health and health behaviour (anxiety disorder, mood disorder, heart disease, TUG time, injury/illness limiting PA, health condition limiting PA, lack of energy limiting PA, smoking history, height, body fat percentage, and FEV 1 ), and sociodemographic (age and household income) variables were included in the same models. Analyses were conducted separately for males and females 3 .…”

“…Dyspnea, or perceived breathlessness, is a symptom commonly reported by individuals with obstructive lung diseases such as asthma and chronic obstructive lung disease (COPD) 1, 2 . The prevalence of dyspnea ranges from 9% in the general population 3 to approximately 50% in individuals with COPD 4-7 . These estimates may be low, as dyspnea is often underreported or not recognized by clinicians 8 .…”

“…Several other factors may influence perceptions of dyspnea. Recently, Ekström et al found that female sex, smoking, presence of asthma, and chronic bronchitis were correlates of dyspnea in healthy adults 3 . FEV 1 , body mass index, anxiety, and depression have also been identified as correlates of resting dyspnea in adults with asthma or COPD 17-19 .…”