Airline Secondhand smoke may worsen respiratory health after decades of exposure cessation

USA: Original research published in Chest has highlighted the impact of airline secondhand smoke (SHS) exposure on worsened respiratory health status and lung functioning almost three decades after exposure cessation.

The article focuses primarily on Occupational lung disease and women's health as most flight attendants were women in the study.

A study published in BMJ, Tobacco Control, concluded that In-flight air quality measurements in 250 aircraft indicate that on permission to smoke, 95% of the harmful respirable suspended particle (smoking section) and 85% of aircraft cabins (non-smoking section) are contributed by SHS. SHS exposure of typical flight attendants in aircraft cabins is estimated to have been greater than 6-fold that of the average US worker and ~14-fold that of the average person.

According to the Centers for Disease Control and Prevention (CDC), SHS contains more than 7,000 chemicals that are toxic and cause cancer. SHS exposure occurs when people who do not smoke breathe in smoke exhaled by people who smoke or burn tobacco products.

Surgeon General's Report, 1964, mentioned that nearly 2.5 million adults (without smoking) have died from health problems due to SHS exposure. There is no safe level of SHS exposure, and even brief exposure is capable of causing damage to the lungs.

The question here is What consequences does airline SHS exposure impose on respiratory health status and lung functioning even after decades of cessation? This critical question of respiratory health has been answered by a research article published in Chest.

A prospective cohort study was conducted by the team of Fernando Diaz del Valle et al. from the Division of Pulmonary Sciences and Critical Care Medicine, Colorado Pulmonary Research Group, Aurora, to evaluate the consequences and damage caused by exposure to secondhand smoke on respiratory health (of flight attendants over 20 years earlier) decades after the cessation has stopped.

St. George's Respiratory Questionnaire (SGRQ) was used to measure the respiratory quality of life and was the primary outcome measured by the researchers. Secondary outcomes measured were general quality of life via the Rand Corporation modification of the 36-item Short Form Health Survey Questionnaire or RAND-36, respiratory symptoms (COPD Assessment Test or CAT), and spirometry.

The key pointers of the study are:

• The participants were flight attendants and were hired at 23.8 years of age

• The exposure to SHS stopped more than 20 years ago.

• The comparison was made between exposed vs. unexposed individuals.

• 183 subjects were exposed to SHS with a mean age of 66.7 years, and were 90.7 % women. The length of exposure time was 16.1 years on average, and stopped exposure 27.5 years before enrollment.

• About 59 subjects were unexposed with a duration of exposure ≤ 1 year

• Worsened SGRQ, with 6.7 units and a P value of 0.001, was related to prior SHS exposure.

• Prebronchodilator spirometry or obstruction was not affected by SHS exposure.

• SHS exposure was related to lower postbronchodilator FEV1 and FEV1/FVC, total lung capacity, and diffusing capacity of the lungs for carbon monoxide.

• The former habit of smoking and SHS exposure worsened SGRQ synergistically with a P value of 0.04.

• SHS exposure in subjects with no prior smoking history was associated with worsened SGRQ of 4.7 units and a P value of 0.006 compared to the unexposed subjects.

The final conclusion by researchers was, "Almost three decades after exposure end, airline SHS exposure is strongly and dose-dependently related to worsening of respiratory health, but less robustly associated with airflow abnormalities used to diagnose COPD."

25 to 45% of COPD is related to exposures other than active smoking. SHS may be an independent cause of COPD, but our study has explored its impact on respiratory health and lung function after exposure cessation. They wrote.

The study mentions how past exposure to SHS worsens the future respiratory health of flight attendants.

This study was presented in abstract form at the 2018 Aspen Lung Conference. It was funded by grants from the Flight Attendant Medical Research Institute (FAMRI ) and the National Institutes of Health.

Reference:

Impact of Airline Secondhand Smoke tobacco smoke exposure on respiratory health and lung function decades after exposure cessation. Chest. 2022; doi:10.1016/j.chest.2022.02.049

Flying the smoky skies: secondhand smoke exposure of flight attendants.Tobacco Control 2004;13:i8-i19.