Vitamin D deficiency: supplementation or test & treat?

The relation between lack of sunshine and rickets is known since the end of the 19th century. In the 1890s, Dr Palm, a Scottish medical missionary, working in Japan noted the absence of rickets. Back in England, he was intrigued by the very high prevalence of rickets. From other medical missionaries, Palm learnt that children in tropical zones, such as China, India and Ceylon were free of rickets. Palm came to the conclusion that “the geography of rickets appears to involve the temperate latitudes of Europe, and he attributed the absence of rickets in tropical countries to plenty of sunshine.