THE USE OF VITAMINS AND MINERALS IN SKELETAL HEALTH: AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND THE AMERICAN COLLEGE OF ENDOCRINOLOGY POSITION STATEMENT.
Endocr Pract. 2018 Oct 2;24(10):915-924. doi: 10.4158/PS-2018-0050. Epub 2018 Jul 23.
Hurley DL, Binkley N, Camacho PM, Diab DL, Kennel KA, Malabanan A, Tangpricha V.
Summary by VitaminDWiki with comments
- >1,000 lU/day for adults age >50
- Goal of >30 ng level in the blood
- If at risk of low vitamin D, take a test or supplement and take a test 3-4 months later
- test should be >4months later if a loading dose is not used
- Loading dose is OK provided it is followed by maintenance dosing of at least 1,000 - 2,000 IU daily
- Loading dose of vitamin D then monthly maintenance is the most popular – Nov 2018 - monthly, not daily
- Vitamin D sufficiency 10 to 30 ng, optimal 40 to 80 ng (no consensus)– May 2018
- Consensus Vitamin D category listing has
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Vitamin D is present only in small amounts in food, and is primarily produced in the skin upon exposure to ultraviolet B radiation (47) and hypovitaminosis D is common when dietary intake is low or poorly absorbed and sun exposure is limited. Vitamin D plays a major role in active GI transport of calcium and may improve muscle function and balance, thereby reducing fall risk (48), and important for patients with osteoporosis as falls cause >90% of hip fractures. Furthermore, vitamin D might also improve the BMD response to bisphosphonates (49, 50). As a result of all these skeletal effects, multiple medical organizations recommend optimizing vitamin D status as a core component in the treatment of osteoporosis. Defining "vitamin D inadequacy" is extremely controversial. RCTs evaluating nutrients are often confounded when "low" nutrient status is not established since nutrients reach a threshold effect in which greater amounts do not provide enhanced physiologic effects (51). As such, providing vitamin D to volunteers who are vitamin D replete should not be expected to demonstrate beneficial effects. Another major confounder is variability of the 25-hydroxyvitamin D [25(OH)D] assay. Despite being the best determinate of bodily vitamin D status (52), substantial variability between 25(OH)D assays and laboratories persists (53). The Office of Dietary Supplements Vitamin D Standardization Program (VDSP) facilitates standardization of the intra-assay variability and bias of 25(OH)D measurements, recommending a 10% coefficient variability (C.V.) for clinical laboratories (54). It is important to appreciate this assay variability. For example, a 25(OH)D laboratory result of 30 ng/mL meeting the 10% C.V. VDSP recommendation means that the "true" value is between 24 and 36 ng/mL (55). Such variability in 25(OH)D results represents a major challenge to meta-analysis of RCTs (56).
Based on this background of uncertainty, systematic reviews find vitamin D supplementation with daily doses of >800 International Units (IU) to reduce hip and non-vertebral fractures (57, 58). A reasonable clinical approach is a vitamin D intake of >1,000 lU/day for adults age >50, as vitamin D inadequacy is common in those with a low BMD or prior fragility fracture. AACE/ACE clinical practice guidelines recommend vitamin D sufficiency be defined as serum 25(OH)D >30 ng/mL, based on an increased prevalence of secondary HPT below this level (22). The IOM reviewed virtually the same evidence base and recommended 25(OH)D >20 ng/mL to define vitamin D sufficiency (52). The level that constitutes "high" vitamin D status is similarly controversial. A conservative upper level, based upon 25(OH)D values achieved by highly sun-exposed young adults is 50-60 ng/mL (59). Reasonable approaches to vitamin D assessment and treatment include an initial measurement of 25(OH)D in patients at risk of deficiency, or alternatively, vitamin D supplementation and subsequent 25(OH)D measurement 3-4 months later to assess dose adequacy. The amount of vitamin D required to correct deficiency and reach target levels varies among individuals due to not yet well-understood factors, to include obesity and ethnicity (60). Use of huge single doses of vitamin D is not recommended as limited data find this approach to paradoxically increase falls and fracture risk (61). It is essential that vitamin D replacement of deficient states be followed by maintenance dosing (e.g., 1,000-2,000 IU/day), recognizing that higher doses may be needed in patients with obesity or malabsorption.