A lack of an adequate source of energy can cause serious problems and even lead to death. This is the finding of a study carried out by Barcelona's public health agency as part of a programme overseen by the EU's Project Sophie. Those at greatest risk are women aged between 70 and 79 with no formal studies. There are three main causes for what is commonly known now as “energy poverty”: low income, poor quality hosing, and the price of energy, especially electricity. The study investigated the mortality rates of people living in social housing between the years 1986 and 2012 and clearly demonstrated that mortality rates were lower in buildings which had been renovated and had thermal insulation installed. In these buildings, there was a clear difference in mortality, especially among women, a fact that is explained by the time women in those dwellings spent at home, according to researcher Andrés Peralta, as well as the lower income of women, especially those living alone. Figures showed that between 10% and 40% of above average mortality can be attributed to energy poverty.