The index grades nations based on variables including life expectancy while imposing penalties on risks such as tobacco use and obesity. It also takes into consideration environmental factors including access to clean water and sanitation. Spain has the highest life expectancy at birth among European Union nations, and trails only Japan and Switzerland globally, United Nations data show. Spain by 2040 is forecast to have the highest lifespan, at almost 86 years, followed by Japan, Singapore and Switzerland, according to the University of Washington's Institute for Health Metrics and Evaluation.