Active and maternal tobacco smoking around birth increase risk for IPF
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Active and passive tobacco smoking around birth was associated with an increase in the risk for idiopathic pulmonary fibrosis, researchers reported in Chest.
“Even though the cause of [IPF] remains unclear, previous small, case-control, studies showed an association between active tobacco smoking and IPF,” Vanesa Bellou, MD, PhD student in the department of hygiene and epidemiology and the department of respiratory medicine and Vangelis Evangelou, MD, associate professor of clinical and molecular epidemiology at the University of Ioannina Medical School, Greece, told Healio. “Taking into account that tobacco smoking is an established risk factor of various chronic medical conditions and has a detrimental impact in respiratory health, we aimed to further examine the association between any tobacco-related exposures in IPF risk a in a large prospective cohort study.”
Researchers studied participants in the UK Biobank population-based study and included 437,453 unrelated white individuals aged 40 to 69 years at baseline. To assess the effect of tobacco smoking-related exposures on IPF risk, researchers identified variables such as maternal smoking around birth, smoking status, age at smoking initiation, age at smoking cessation, presence of smokers in the household and cigarettes smoked per day.
Over a median follow-up of 8.2 person-years, 802 cases of incident IPF occurred in 1,234 individuals (mean age, 62 years; 59% men).
In a multivariable model, researchers observed an association between risk for IPF and smoking status (HR = 2.12; 95% CI, 1.81-2.47), maternal smoking (HR = 1.38; 95% CI, 1.18-1.62) and smoking in the household (HR = 1.26; 95% CI, 1.02-1.57).
The researchers reported a dose-response relationship between pack-years of smoking and IPF risk among ever smokers with every 1 pack-year increase (HR = 1.013; 95% CI, 1.009-1.016).
Researchers also observed “an additive and multiplicative interaction” between maternal smoking and smoking status. Compared with never smokers who were not exposed to maternal smoking, the HR for developing pulmonary fibrosis was 2.89 (95% CI, 2.43-3.45) for ever smokers who were exposed to maternal smoking and the HR for developing IPF was 2.91 (95% CI, 2.35-3.61).
The HR for pulmonary fibrosis was 2.08 (95% CI, 1.59-2.71) for individuals who were exposed to both maternal smoking around birth and household smoking and the HR for IPF was 2.12 (95% CI, 1.57-2.86) compared with those not exposed to either.
“Maternal smoking around birth has been linked with abnormal lung development and lower lung function in adult life in previous literature. Existing literature has only considered environmental factors of adult life as risk factors of IPF. Our study was the first that depicted an association between a risk factor acting in early life with IPF risk, indicating that the disease might have been a developmental origin,” Bellou and Evangelou told Healio.
According to the researchers, there are multiple measures in place to reduce the prevalence of active and passive tobacco smoking, which may also serve as a primary prevention measure for IPF.
“Given that our study is the first examining the role of second-hand tobacco smoke exposure around birth, more research is needed to replicate this finding in independent prospective cohorts,” Bellou and Evangelou said. “Also, more research is needed to shed light on risk factors that interact with tobacco smoking, because IPF is a relatively rare disease, despite the high prevalence of smoking habit and the relatively high effect size of the exposure in risk for IPF.”
For more information:
Vanesa Bellou, MD, and Vangelis Evangelou, MD, can be reached at vangelis@uoi.gr.