Fig. 2From: World-wide research architecture of vitamin D research: density-equalizing mapping studies and socio-economic analysisDensity-equalizing mapping of socioeconomic features of vitamin D research of global vitamin D research activities (threshold: 30 vitamin D related articles). a Vitamin D articles were calculated in relation to GDP in 1000 bn USD. b Vitamin D articles were calculated in relation to the population in mill. InhabitantsBack to article page