The rise and rise of vitamin D testing

Moynihan and colleagues’ report highlights the increasing trend for overdiagnosis, particularly of endocrine disorders. Similar concerns exist for overdiagnosis and overtreatment of vitamin D deficiency. 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 $95.6m in 2010, on average 59$C150m (£95m; €120m; $147m) will be spent on vitamin D testing in 2012, up from$38m in 2009. Similarly, the UK has seen a sixfold increase in such tests between 2007 and 2010

The Vitamin D paradox : bone density testing in females aged 45 to 74 did not increase over a ten-year period despite a marked increase in testing for vitamin D

Aim: To determine whether increased vitamin D testing resulted in improved osteoporosis detection in Australian females aged 45-74 yr. Methods: Longitudinal analysis of bone densitometry, 25-hydroxyvitamin D (25(OH)D) and full blood count (FBC) testing between 2001 and 2011. The number and rate of tests per 100,000 individuals and benefit in dollars for bone densitometry, 25(OH)D and FBC from 2001-2011 for individuals aged 45-74 were obtained from Medicare Australia. Results: There was a disproportionate increase in 25(OH)D testing compared to bone density testing from 2001 to 2011, whereby 25(OH)D testing increased from 26,666 to 1.65 million p.a. and bone density testing increased from 41,453 to 66,100 p.a. Bone densitometry increased approximately 1.2 fold, whereas 25(OH)D testing increased by 55.2, 41.2 and 34.3 fold in females aged 45-54, 55-64 and 65-74, respectively. This represents an increase in annual benefits from approximately $2.5-$4.1 million for bone density testing and $0.7-$40.5 million for 25(OH)D testing over the period. Conclusions: This study demonstrates that improved detection of vitamin D deficiency is not being translated into better detection in at risk women of the consequences of vitamin D deficiency on target organs such as bone. This failure to translate rising awareness and better detection of vitamin D deficiency into physiological outcomes is a massive missed opportunity for improved bone health and reduced fracture risk. We propose that clinical practice guidelines be introduced not only for the purpose of diagnosis and testing for vitamin D, but to include recommendations for bone health testing in at risk individuals

Seasonal reduction in vitamin D level persists into spring in NSW Australia : implications for monitoring and replacement therapy

Context: Seasonal variation in 25-hydroxyvitamin D [25OHD] status and its relationship to gender, age, socioeconomic and geographic determinants in Australians has not been described in large biomedical sampling cohorts. Objectives: To analyse 25OHD levels in all primary tests undertaken consecutively in a 2-year period to determine the prevalence of 25OHD deficiency and its relation to patient setting, gender, age, season, urban or rural residency, socioeconomic status, latitude and longitude. Design: We assessed 24 819 ambulatory and inpatient samples taken from the largest reference laboratory in NSW, Australia between 01 July 2008 and 30 July 2010. Main outcome measures: Serum 25OHD was measured using chemiluminescent immunoassay. Vitamin D deficiency was defined as 25OHD 79 years, socioeconomically disadvantaged and from a major city. Conclusion: This cross-sectional study demonstrates the extent and duration of 25OHD deficiency is greater than expected, and particular individuals are at higher risk. Our findings imply that supplementation guidelines need to be modified and strengthened

Evidence of overtesting for vitamin D in Australia : an analysis of 4.5 years of Medicare Benefits Schedule (MBS) data

Objective: To comprehensively examine pathology test utilisation of 25-hydroxyvitamin D (25(OH)D) testing in each state of Australia to determine the cost impact and value and to add evidence to enable the development of vitamin D testing guidelines. Design: Longitudinal analysis of all 25(OH)D pathology tests in Australia. Setting: Primary and Tertiary Care. Measurements: The frequency of 25(OH)D testing between 1 April 2006 and 30 October 2010 coded for each individual by provider, state and month between 2006 and 2010. Rate of tests per 100 000 individuals and benefit for 25(OH)D, full blood count (FBC) and bone densitometry by state and quarter between 2000 and 2010. Results: 4.5 million tests were performed between 1 April 2006 and 30 October 2010. 42.9% of individuals had more than one test with some individuals having up to 79 tests in that period. Of these tests, 80% were ordered by general practitioners and 20% by specialists. The rate of 25(OH)D testing increased 94-fold from 2000 to 2010. Rate varied by state whereby the most southern state represented the highest increase and northern state the lowest increase. In contrast, the rate of a universal pathology test such as FBC remained relatively stable increasing 2.5-fold. Of concern, a 0.5-fold (50%) increase in bone densitometry was seen. Conclusions: The marked variation in the frequency of testing for vitamin D deficiency indicates that large sums of potentially unnecessary funds are being expended. The rate of 25(OH)D testing increased exponentially at an unsustainable rate. Consequences of such findings are widespread in terms of cost and effectiveness. Further research is required to determine the drivers and cost benefit of such expenditure. Our data indicate that adoption of specific guidelines may improve efficiency and effectiveness of 25(OH)D testing

The rising cost of vitamin D testing in Australia : time to establish guidelines for testing

We analysed the Medicare Benefits Schedule (MBS) to determine the economic impact of vitamin D testing in Australia from 1 January 2000 to 31 December 2010

Thyroid Ultrasonography Consistently Identifies Goiter in Adults Over the Age of 30 Years Despite a Diminished Response with Aging of the Thyroid Gland to the Effects of Goitrogenesis

Iodine deficiency is a national health problem in India and we have recently reported on the severity of IDD in adults and children in Gujarat province. The aim of this study was to determine the utility of thyroid ultrasonography to detect goiter in adults from an iodine-deficient population of Gujarat. We studied 472 adults selected by random household surveys. Data were collected on height, body weight, mid-upper arm circumference, thigh circumference, triceps skinfold thickness, thyroid size (palpation and ultrasonography), and diet. Casual urine samples for iodine (UI) and blood spots for TSH estimation were obtained. Endemic goiter is a major public health problem in Gujarat State, India and is probably caused by multiple factors including iodine deficiency, malnutrition, and other dietary goitrogens. These results indicate that thyroid US consistently detects goiter in adults despite a diminished thyroidal response to variable goitrogenic stimuli

ABCB1 and ABCC1 single-nucleotide polymorphisms in patients treated with clozapine

Clozapine (CZ) has superior efficacy to other antipsychotic agents in the treatment of schizophrenia and has been extensively used in clinical practice. ATP-binding cassette (ABC) transporter proteins are responsible for the distribution of various molecules as well as drugs across extracellular and intracellular membranes, including the blood–brain barrier. Genetic variations in these proteins can account for differences in treatment response. We investigated the influence of ABCB1 rs1045642 and ABCC1 rs212090 single-nucleotide polymorphisms (SNPs) on CZ serum level, clinical outcome, and changes in body mass index (BMI) in the first year of CZ treatment. These polymorphisms influenced baseline BMI in males (p=0.009 and 0.054, B1 and C1, respectively), changes in BMI in males after 3 (p=0.026, ABCB1) and 12 months (p=0.022, ABCC1) of CZ treatment, and level of diastolic pressure (p=0.002 and 0.051, respectively). The combination of ABCB1 + ABCC1 homozygote SNPs was associated with increased CZ and norclozapine serum levels (p=0.054 and 0.010, respectively). ABC transporter SNPs could be potential biomarkers for CZ-induced weight gain and cardiovascular complications. Further pharmacogenetic research is warranted to help clinicians with their treatment decision, including concomitant use of drugs and prevention of side effects