Intended for healthcare professionals

Letters Preventing overdiagnosis

# The rise and rise of vitamin D testing

BMJ 2012; 345 (Published 16 July 2012) Cite this as: BMJ 2012;345:e4743
1. Kellie Bilinski, dietitian1,
2. Steven Boyages, clinical professor, senior endocrinologist2
2. 2University of Sydney, Department of Endocrinology, Westmead Hospital
1. kellie.bilinski{at}me.com

Moynihan and colleagues’ report highlights the increasing trend for overdiagnosis, particularly of endocrine disorders.1

Similar concerns exist for overdiagnosis and overtreatment of vitamin D deficiency.2 3 Currently, the appropriate timing and frequency of testing for the diagnosis of vitamin D deficiency is unclear. The cost of testing in Australia increased from $A1m (£0.66m; €0.83m;$1m) in 2000 to $95.6m in 2010, on average 59% each year.2 Similarly, in Ontario, Canada, testing increased 25-fold from 2004 to 2010. Projections suggest that$C150m (£95m; €120m; $147m) will be spent on vitamin D testing in 2012, up from$38m in 2009.4 Similarly, the UK has seen a sixfold increase in such tests between 2007 and 2010.5

Our data show that the past 11 years have seen an unsustainable growth in vitamin D testing in Australia (figure). These findings have widespread consequences in terms of quality of care, unnecessary cost, and potential overdiagnosis. Further studies are needed to determine whether this increased testing translates into improved vitamin D status in the population and subsequent health outcomes. Worryingly, however, this large increase in vitamin D testing did not translate into increased testing for osteoporosis, as shown by the flat trend in bone density measurements (figure).

Requests per 100 000 for vitamin D, full blood count, and bone densitometry between 2000 and 2011

Guidelines are urgently needed to limit overtesting, overdiagnosis, and as a consequence overtreatment for vitamin D deficiency.

## Notes

Cite this as: BMJ 2012;345:e4743

## Footnotes

• Competing interests: None declared.

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