Table 5. Summary of Previous Studies.

Researcher/Year	Sample Size	25-Hydroxyvitamin D
Klein GL/2002 ( 7 )	11	low in 90% (7 year follow up)
Gottschlich MM/2004 ( 16 )	69	low in 26.2%, very low in 11%
Klein GL/2009 ( 17 )	8	16 ng/mL
Rousseau AF/2015 ( 19 )	26	21.5 ng/mL