How bad is secondhand tobacco smoke (SHS)?  This has been debated.  When I come out of an office room and the entire room smells of smoke, even though no one has smoked in the room, I know this is detrimental.  More proof of this comes from an article which shows that SHS is associated with an increase in the severity of children hospitalized with influenza (J Pediatr 2013; 162: 16-21).

In this study of 117 children, 40% were exposed to SHS.  They had increased need for intensive care (30% vs. 10%), increased intubation (13% vs. 1%), and longer length of stay (LOS) (4 days vs. 2.4 days). In children with chronic conditions, the LOS was 10 vs. 3.5.  After controlling for multiple variables, the authors found that SHS exposure was associated with a 4.7 fold increase in the likelihood of ICU admission and a 70% LOS.

This study had many limitations.  It was a retrospective chart review.  Patients between 2002-2009 were identified initially by the discharge diagnosis of influenza.  Among the 171 charts identified, 117 had a positive influenza culture and adequate data to retrieve.  As a retrospective review, it is possible that screening for smoke exposure was more common in the more severely affected cases.

Additional references:

• -NEJM 2011; 365: 1222. Treating smokers -useful review. Treating Smokers in the Health Care Setting — NEJM
• -NEJM 2011; 365: 1193. Cytisine -inexpensive- helps with smoking cessation (8.4% success vs 2.4%in placebo). Placebo-Controlled Trial of Cytisine for Smoking Cessation — NEJM
• -NEJM 2008 358; 2249. Smoking and role of social networks. 80% of smokers start by age 18. The Collective Dynamics of Smoking in a Large Social Network …