Developing countries 109 human 65 Humans 56 developing country 56 Developing Countries 46 female 34 male 33 adult 30 Article 29 Male 23 Female 22 Adult 18 developing countries 18 Malaysia 16 developing world 16 major clinical study 16 aged 15 Developed Countries 14 Economics 14 Sustainable development 14 income 14 middle income country 14 priority journal 14 Developed countries 13 Income 13 controlled study 13 middle aged 13 prospective study 13 Child 12 China 12