3X more kids were vitamin D deficient when entering UK hospitals than 4 years before
Tripling in children suffering Vitamin D deficiency Telegraph
Unfortunately the article does not give the source of the information
Official figures show that 4,638 children admitted to NHS hospitals in 2013/14 were found to be suffering a Vitamin D deficiency, compared with 1,398 cases in 2009/10.
Note: UK considers low vitamin D to be < 10 ng/mL
See also VitaminDWiki
- Half of children with chronic illness had low levels of vitamin D – April 2013
- note - the study on this page is for children who were sick enough to go to the hospital
Incidence of 22 health problems related to vitamin D have doubled in a decade
Vitamin D reduced so low that Victorian age diseases are returning
Overview Deficiency of vitamin D which show a big drop in vitamin D levels
Military and Vitamin D - many studies
- average level dropped by half in 18 years. Most likely % with deficiency more than doubled.
UK program to increase Vitamin D (Healthy Start) continues to be a farce - Nov 2014
Only half as many people had >30 ng of vitamin D 16 years later

2X increase in % of Canada children 6-11 who are deficient

Some of the reasons why

The huge decline in vitamin D levels make a farse out of vitamin D studies which span 10 to 20 years
The studies almost always assume that the vtiamin D levels are a constant in the population.
When, in reality, the vitamin D levels are constantly falling.