Introduction:
To provide a systematic review on the existing literature on the population burden of disease due to second-hand smoke (SHS) and to identify methods, diseases, and outcomes for estimating mortality and morbidity attributable to SHS exposure in the 28 European (EU) Countries within the Project “Tackling second-hand tobacco smoke and e-cigarette emissions: exposure assessment, novel interventions, impact on lung diseases and economic burden in diverse European populations” (TackSHS) funded by the European Union’s Horizon 2020 Research and Innovation Programme.

Methods:
We performed a literature search in PubMed and SCOPUS with the eligibility criteria of selecting original publications evaluating the burden of disease due to SHS exposure published after 1 January 2007 in English language. PRISMA recommendations were followed. We identified 505 studies; 434 relevant after screening; 79 eligible.

Results:
We included 62 studies. Twenty-three were carried out in EU countries, 13 in the US, 15 in China and other Eastern countries and the remaining in Australia, New Zealand, Morocco, and Israel. Almost all studies were based on the comparative risk assessment method. SHS exposure was mainly assessed through surveys asking for SHS exposure in home or workplace, in some cases also exposure in car or public places was considered, and in 6 and 5 studies exposure was respectively cotinine-measured and modelled. The diseases mainly studied were: lung cancer, ischemic hearth disease, and stroke in adults; low birth weight, sudden infant death syndrome, lower respiratory tract infection, otitis media, and asthma in children. The outcomes were number of cases and deaths, disability adjusted life years, and costs.

Conclusions:
Although outcomes and diseases change depending on the objective of each study, the CRA methodology and the household or workplace SHS exposure assessment using surveys are used by almost all the studies and they will be adopted also in TackSHS.

Funding:
This document was developed under the Project TackSHS that received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 681040.