The Health Evidence Network (HEN) is an information service for public health decision-makers in the WHO European Region, in action since 2003 and initiated and coordinated by the WHO Regional Office for Europe under the umbrella of the WHO European Health Information Initiative (a multipartner network coordinating all health information activities in the WHO European Region). HEN supports public health decision-makers to use the best available evidence in their own decisionmaking and aims to ensure links between evidence, health policies and improvements in public health. The HEN synthesis report series provides summaries of what is known about the policy issue, the gaps in the evidence and the areas of debate. Based on the synthesized evidence, HEN proposes policy considerations, not recommendations, for policy-makers to formulate their own recommendations and policies within their national context