World leaders have pledged to take wide-ranging action to prevent millions of deaths from cancer, diabetes, and heart and lung disease by tackling the key causes — smoking, excessive drinking, lack of exercise and unhealthy diets dominated by fast food. But the 13-page political declaration approved at the first-ever General Assembly meeting on chronic diseases which ended Tuesday left unanswered the question of coordinating an international response to what the leaders called “a challenge of epidemic proportions.” The declaration notes “with profound concern” that according to the World Health Organization, an estimated 36 million of the 57 million global deaths in 2008 were due principally to cancer, diabetes and heart and lung diseases — including about 9 million men and women below the age of 60. WHO said 80 percent of these deaths were in developing countries. At a final round-table discussion, Prime Minister Denzil Douglas of St. Kitts and Nevis said, “Our response must be urgent, it must be comprehensive, and it has to be fully coordinated at the national, regional and local levels.” Douglas, who chairs the Caribbean Community known as CARICOM, said priority must be given to international coordination so there can be effective monitoring of the diseases and effective measures to reduce the risk factors and strengthen health care systems, especially in developing countries where cases of the four diseases are increasing rapidly.