Tobacco Smoking and Second-Hand Smoke Exposure Impact on Tuberculosis in Children

Abstract

Mycobacterium tuberculosis; Child; Passive smoking

Tuberculosis micobacteriana; Niño; Tabaquismo pasivo

Tuberculosi micobacteriana; Infant; Tabaquisme passiu

Little is known about whether second-hand smoke (SHS) exposure affects tuberculosis (TB). Here, we investigate the association of cigarette smoke exposure with active TB and latent TB infection (LTBI) in children, analyzing Interferon-Gamma Release Assays’ (IGRAs) performance and cytokine immune responses. A total of 616 children from contact-tracing studies were included and classified regarding their smoking habits [unexposed, SHS, or smokers]. Risk factors for positive IGRAs, LTBI, and active TB were defined. GM-CSF, IFN-γ, IL-2, IL-5, IL-10, IL-13, IL-22, IL-17, TNF-α, IL-1RA and IP-10 cytokines were detected in a subgroup of patients. Being SHS exposed was associated with a positive IGRA [aOR (95% CI): 8.7 (5.9–12.8)] and was a main factor related with LTBI [aOR (95% CI): 7.57 (4.79–11.94)] and active TB [aOR (95% CI): 3.40 (1.45–7.98)]. Moreover, IGRAs’ sensitivity was reduced in active TB patients exposed to tobacco. IL-22, GM-CSF, IL-5, TNF-α, IP-10, and IL-13 were less secreted in LTBI children exposed to SHS. In conclusion, SHS is associated with LTBI and active TB in children. In addition, false-negative IGRAs obtained on active TB patients exposed to SHS, together with the decrease of specific cytokines released, suggest that tobacco may alter the immune response.

This research was supported by: (i) a grant from the Instituto de Salud Carlos III (PI 13/01546, PI16/01912, and PI18/00411), integrated in the Plan Nacional I+D+I and co-funded by the ISCIII Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER) and CERCA Programme/Generalitat de Catalunya; and (ii) a grant from the Sociedad Española de Neumología y Cirugía Torácica (SEPAR; Barcelona, Spain) (Smoking Integrated Research Programme Call).