Late consequences of occupational exposure to second-hand smoke

A study of flight attendants suggests that the effects of secondhand smoke on lung health may occur long after prolonged exposure.

The respiratory consequences of long-term exposure to second-hand smoke have long been identified and are well documented.[1]The long-term consequences of prolonged exposure to second-hand tobacco smoke, however, are more difficult to establish.

A US study suggests that long-term consequences on lung health have been observed in air crews[2]In the United States, smoking bans on aircraft were implemented between 1988 and 1989 for domestic flights, and from 1994 to 1997 for international flights.

Correlation between years of service and respiratory health status

The study collected data from 293 individuals from flight personnel who had never smoked, including 193 who had been exposed to passive smoking during their years of service, and 103 who had not been exposed. Participants with previous cardiopulmonary pathologies were excluded from the sample. The latter included a large majority of women (63 % in the first group, 81 % in the second). The indicators recorded were the levels of desmonin and isodesmosine (DI) in plasma – two amino acids resulting from the degradation of elastin, present in lung tissue – as well as the number of years of exposure to passive smoking, which ranged from 11 to 31 years of service. These variables were compared with spirometric measurements or other more in-depth examinations providing information on the state of respiratory functions, carried out between June 2014 and October 2019.

The results show a clear correlation between the high presence of markers of elastin degradation, measurements of respiratory function and the number of years of service with exposure to second-hand smoke, much higher than that observable by the simple effect of aging and in subjects who have not been subjected to this exposure for a long time. The authors deduce an influence of this exposure to second-hand smoke on the degradation of elastin and on the appearance of respiratory disorders, this at a distance of approximately 25 years.

Consequences that can be very far away in time

Other studies had previously shown that flight personnel were three times more prone to respiratory diseases such as chronic obstructive pulmonary disease (COPD) than the rest of the US population, without being able to establish what caused these differences.[3]. This study considers that the presence of respiratory disorders can be attributable to prolonged exposure to second-hand smoke, even when this occurs in the distant past. It thus highlights the need to explore the occupational history of patients with respiratory disorders, and shows again that exposure to smoking, including passive smoking, can have very distant consequences.

Keywords: passive smoking, COPD, flight personnel

M.F.

[1] Fischer F, Kraemer A. Meta-analysis of the association between second-hand smoke exposure and ischemic heart diseases, COPD and stroke. BMC Public Health. 2015;15:1202-1202.

[2] Mustra Rakic J, Zeng S, Rohdin-Bibby L, et al. Elastin degradation and lung function deterioration with remote secondhand tobacco smoke exposure in never-smokers. Chronic Obstr Pulm Dis. 2022;9(3):377-393.

[3] McNeely E, Gale S, Tager I, et al. The self-reported health of US flight attendants compared to the general population. Environ Health. 2014;13(1):13.