Incidence and risk factors for idiopathic pulmonary fibrosis in individuals aged 75 years and older in an ultra-aging society

Abstract

Background: Limited data exist on idiopathic pulmonary fibrosis (IPF) incidence and risk factors in elderly populations, making early intervention and preventive strategies challenging. Further research is needed to address this gap and improve outcomes. Objectives: This study used the Korean National Health Insurance Service (NHIS) database to investigate factors associated with the development of IPF in elderly people. Design: A retrospective cohort study was conducted to evaluate risk factors for IPF in an elderly population. Methods: This study evaluated 1,250,901 participants aged 75 years and older with health screening examination records in the NHIS database from 2012 to 2015. Cox proportional hazards regression models were used to assess the associations between IPF risk and demographics, lifestyle factors, and comorbidities, and subgroup analyses were used to explore multifactor interactions. Results: During a median follow-up of 7.4 years, 3955 participants developed IPF, for an incidence rate of 0.38 per 1000 person-years. Elderly participants (aged 75–85 years) exhibited higher IPF incidence than extremely elderly participants (⩾85 years) (0.40 vs 0.17 per 1,000 person-years, p < 0.01), though the difference was not significant in the multivariable analysis. The factors independently associated with increased IPF risk were male sex (adjusted hazard ratio [aHR] = 2.56, 95% confidence interval [CI] = 2.35–2.78), high body mass index (BMI) (aHR=1.45, 95% CI = 1.34–1.56 ), smoking (aHR = 1.24, 95% CI = 1.13–1.37 for ever-smokers < 20 pack-years [PYs]; aHR = 1.28, 95% CI = 1.17–1.39 for ever-smokers ⩾ 20 PYs), dyslipidemia (aHR = 1.17, 95% CI = 1.08–1.26), chronic kidney disease (aHR = 1.08, 95% CI = 1.01–1.16), and chronic obstructive pulmonary disease (COPD) (aHR = 1.49, 95% CI = 1.37–1.63). Additive or synergistic effects were observed among sex, BMI, smoking, and dyslipidemia, notably among males, and interactions between COPD and smoking status modulated IPF risk. Conclusion: Male sex, high BMI, smoking, and dyslipidemia might additively or synergistically increase the IPF risk among elderly people, highlighting the need for targeted prevention strategies in those populations.