Global health is the health of populations in the global context; it has been defined as 'the area of study, research and practice that places a priority on improving health and achieving equity in health for all people worldwide'. Problems that transcend national borders or have a global political and economic impact are often emphasized. Thus, global health is about worldwide health improvement (including mental health), reduction of disparities, and protection against global threats that disregard national borders. Global health is not to be confused with international health, which is defined as the branch of public health focusing on developing nations and foreign aid efforts by industrialized countries. Global health can be measured as a function of various global diseases and their prevalence in the world and threat to decrease life in the present day. The predominant agency associated with global health (and international health) is the World Health Organization (WHO). Other important agencies impacting global health include UNICEF and World Food Programme. The United Nations system has also played a part with cross-sectoral actions to address global health and its underlying socioeconomic determinants with the declaration of the Millennium Development Goals and the more recent Sustainable Development Goals.