What is Driving the Vitamin D Epidemic? (More Testing)

AA Kerber et al. J Pediatr 2021; 239; 212-218. Stable Rates of Low Vitamin D Status Among Children Despite Increased Testing: A Population-Based Study

Methods: The Rochester Epidemiology Project (REP) was used to identify Olmsted County, Minnesota residents aged <19 years who had 25-hydroxyvitamin D [25(OH)D] levels measured between January 2, 2002 and December 31, 2017.  Using each patient’s first 25(OH)D measurement during this period, patients were categorized as vitamin D deficiency/insufficiency if Vit 25(OH)D level was <20 ng/mL.

To convert nmol/L to ng/mL= nmol/L x 0.401 OR nmol/L =ng/mL x 2.496

Key finding:

  • There was a 42-fold increase in the proportion of the county’s pediatric population tested each year, starting at 3.7 per 10,000 persons in 2002 and increasing to 156.1 per 10,000 persons in 2017
  • During the 16-year period, the incidence of vitamin D deficiency/insufficiency (per 10,000 persons) increased from 1.7 in 2002-2003 to 19.9 in 2016-2017, but the proportion that were tested and had vitamin D deficiency/insufficiency remained stable –rates of 21.9% in 2006-2007 and 18.5% in 2016-2017
  • There was a higher rate of Vit D deficiency/insufficiency in females (22.8%) vs males (16.9%) (P<.001)
  • There was a significant association with obesity and Vit D deficiency/insufficiency (32.7% with moderate and 32.9% with severe obesity). It is unclear whether this is a causal link or an association (perhaps associated with less outdoor activity)
  • Limitation: Study was performed in Olmstead county which is 90-95% white; this limits generalizability (though other reports have noted increased testing rates as well in other locations)

My take: Clearly more kids are being screened for vitamin D deficiency. More data is needed on whether this results in any meaningful improvements in outcomes and the associated costs. In addition, it is important to recognize that vitamin D levels can be inversely proportional to inflammatory conditions and can improve without supplementation by addressing these disorders.

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