Should measurement of vitamin D and treatment of vitamin D insufficiency be routine in New Zealand?
Epidemiological studies have reported associations between lower vitamin D levels and a great variety of diseases, prompting calls for widespread treatment of individuals with low vitamin D levels. Most of New Zealand's population have vitamin D levels for at least part of the year that are considered insufficient (25-hydroxyvitamin D <50-80 nmol/L). However, evidence for benefits of vitamin D supplementation in such populations is controversial and there is some evidence of harmful effects. Until adequately powered, randomised, controlled trials of vitamin D supplementation demonstrate safe improvements in health, clinicians should not focus on detecting/treating individuals with vitamin D insufficiency, instead treating those at high risk of vitamin D deficiency (25-hydroxyvitamin D <25 nmol/L), such as the frail elderly, and those with specific clinical indications. Treatment for such individuals does not require vitamin D measurements. Requests for vitamin D measurements in Auckland have nearly quadrupled in the past decade, from 8500 in the year 2000 to 32,800 in 2010, with substantial increases in cost. Vitamin D measurement is often inaccurate and imprecise, and the vast majority of tests performed currently do not reveal vitamin D deficiency. Therefore, a move away from routine vitamin D measurements seems sensible, though they are still indicated when investigating suspected metabolic bone disease or hypocalcaemia.
Bone and Joint Research Group, Department of Medicine, University of Auckland, Private Bag 92 019, Auckland, New Zealand. m.bolland@auckland.ac.nz
Mark J
MJ
Bolland
Andrew
A
Grey
James S
JS
Davidson
Tim
T
Cundy
Ian R
IR
Reid
D019587:Dietary Supplements / Q000009:adverse effects; D017048:Health Care Costs; D006801:Humans; D008403:Mass Screening; D015201:Meta-Analysis as Topic; D009520:New Zealand; D019370:Observation; D015203:Reproducibility of Results; D014807:Vitamin D / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000175:diagnosis / Q000188:drug therapy / Q000191:economics; D014815:Vitamins / Q000009:adverse effects / Q000627:therapeutic use*
D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D