Association between reproductive lifespan and lung function among postmenopausal women

Correspondence to: Hye Yun Park, MD, PhD. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, South Korea. Email: hyeyunpark@skku.edu; Juhee Cho, PhD. Department of Clinical Research Design and Evaluation, SAIHST, Sungkyunkwan University, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, South Korea. Email: Jcho@skku.edu. BACKGROUND: Both age of menarche and menopause are associated with impaired lung function. However, there is limited data on the association between reproductive lifespan (RL) and lung function. This study aims to evaluate the association between RL and lung function among postmenopausal women. METHODS: In the Korean National Health and Nutrition Examination Survey (2010–2015), an annual cross-sectional survey of a national representative sample of non-institutionalized Korean population, the postmenopausal women aged 40–64 years who underwent spirometry were included. Spirometry was performed according to the recommendations of the American Thoracic Society and European Respiratory Society, and RL (years) was calculated by subtracting the age at menarche from age at menopause. RESULTS: Among 3,410 postmenopausal women, the mean RL were 34.91 (standard error 0.07). In spline regression models, shorter RL was associated with reduced predicted forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)), and the associations were linear. In multivariable-adjusted models, the prevalence ratios (95% confidence interval) for abnormal lung function (restrictive or obstructive ventilatory disorder) comparing women with RL ≤30 years and >30 to <39 years to women with RL ≥39 years were 1.83 (1.15, 2.50) and 1.42 (1.01, 1.84), respectively. Women with RL ≤30 years showed a 2.13 (1.28, 3.54) times higher prevalence of restrictive ventilatory disorder than women with RL ≥39 years. CONCLUSIONS: In postmenopausal women, a shorter RL was associated with abnormal lung function, particularly with a restrictive ventilatory disorder.