World-wide research architecture of vitamin D research: density-equalizing mapping studies and socio-economic analysis.

Background: Despite the numerous associations of vitamin D with health and disease, vitamin D deficiency is still common from a global perspective. While basic research, clinical and preventive activities grow constantly in vitamin D research, there is no in-depth analysis of the related global scientific productivity available so far.

Methods: Density equalizing mapping procedures (DEMP) were combined with socioeconomic benchmarks using the NewQIS platform.

Results: A total of 25,992 vitamin D-related research articles were identified between 1900 to 2014 with a significant increase (r = .6541) from 1900 to 2014. Authors located in Northern America - especially in the USA - distributed the majority of global vitamin D research, followed by their Western European counterparts. DEMP-analysis illustrates that Africa and South America exhibit only minor scientific productivity. Among high-income group countries, Scandinavian nations such as Denmark or Finland (2147.9 and 1607.7 vitamin D articles per GDP in 1000 billion USD) were highly active with regard to socioeconomic figures.

Conclusion: Networks dedicated to vitamin D research are present around the world. Overall, the Northern American and Western European nations occupy prominent positions. However, South American, African and Asian countries apart from Japan only play a minor role in the global research production related to vitamin D. Since vitamin D deficiency is currently increasing in the Americas, Europe and parts of the Middle East, research in these regions may need to be encouraged.