What would be the cause of above normal levels of Vitamin D with normal calcium levels, apart from high Vitamin D intake (158nmol/L), upper normal level limit being 142nmol/L? What signs and symptoms would be manifested with toxic levels of Vitamin D?
Serum concentrations of ~150 nmol.L are not uncommon in those working outdoors (at least in sunny climates). Perhaps the indiviudal in question may have recently been exposed to frequent bouts of sun exposure (or using sun beds?). This could be one factor explaining this observation.
Failing that there are some other questions to address;
- Does the individual take growth hormone? This can stimulate production of vitamin D.
- Does the individual have large amount of lean body mass? Our lab has found that those with larger body mass show higher basal levels of vitamin D (pre supplementation).
-Do you beleive that you are likely to see toxicity symptoms at ~150 nmol.L? This is extremely unlikely.
The important part of my answer may lie in that final question as I dont believe 158 nmol.L is toxic regardless of the US institute of medicine guidelines. This is far too conservative and many of us would suggest that based on those residing outdoors in such rich climates, concentrations of 120-150 nmol.L are normal. You certainly wouldnt expect to see any change in calcium at these serum 25[OH]D concentrations.
For reference, those that do experience vitamin D toxicity (which can only occur through supplementation and not from sun exposure as this is a self regulated process) typically have abnormally high calcium (hypercalcemia), poor appetite, nausea and vomiting, weakness, frequent urination and kidney problems also may occur.
I hope that somewhat answers your question.
Best wishes
Thank you for your answer. Well the person I mentioned mostly stays indoors and aged 50 +, is on hypertensive medications as well as diabetic medications. His blood tests showed higher vit D levels which was surprising because he doesn't takes any vit D supplements, calcium levels are within normal range. Person doesn't shows any signs of toxicity by the way what would be signs of Vit D toxicity with calcium levels being normal?
The level you quote is not particularly high and certainly not at a level where you would see any toxic effects. As far as I am aware vitamin D toxicity is as a result of raised Ca, not the vit D itself. So as far as vitamin D and Ca go, your individual would appear 'normal'. The intriguing question is how this person has achieved such a level without any obvious UV exposure or supplementation. I assume by vitamin D level you mean 25OHD? Do they take any other supplements that might contain vit D? What time of year was the blood test done?
Yes by vit D I mean 25OHD. No the person does not take any supplements ,only the medication as I have mentioned above ,but I don't know about his diet to be frank. The blood tests were done in first week of Jan 2014.
I wouldn't worry about diet, you would have to eat a lot of sardines to reach this level (might be worth asking though!). Only 2 other things spring to mind: (1) has this person had any sort of phototherapy and (2) are you confident your 25OHD assay is robust? Some assays can be extremely variable.
No the person did not have any sort of phototherapy. About the assay well it was done in Heartlands Hospital Birmingham, I guess a repeat test would be confirmatory.
Serum level of 142 nmol/L (57 ng/ml) is quite nominal, although it is surprisingly high for no known supplementary intake or sunlight (UV) exposure.
See Garland et al, Vitamin D Supplement Doses and Serum 25-Hydroxyvitamin D in the
Range Associated with Cancer Prevention, Anticancedr Research 31: 617-22 (2011)
Known toxic level for 25(OH)D is >500 nmol/L. See Hathcock et al, Risk Assessment for Vitamin D, Am J Clin Nutr 85:6-18 (2007) and Vieth R., Vitamin D and Cancer mini-symposium: the risk of additional vitamin D. An Epidemiol 19: 441-445 (2009)
I suggest retesting. 25OHD assays can sometimes be in error.
Lai JK, Lucas RM, Banks E, Ponsonby AL; Ausimmune Investigator Group. Variability in vitamin D assays impairs clinical assessment of vitamin D status. Intern Med J. 2012 Jan;42(1):43-50.
THANKS, I HAVE THE SAME PROBLEM WITH 40 YS WOMEN. she tested twice and she has more than 100 ng/ml. 1 test and 154 ng/ml in 2 tests.
she has 3 severe atherosclerotic plaque in the carotid sin & dx : 46% -- 36% and 22%
no supplement
no fortified food
no UV lamp
no outside work (she stay at the office from 8 to 20)
no fish in her diet
her diet is based only on dinner carbohydrates: bread and pasta sometimes some cake... she said-
she is overweight
she doesn't like sport
she has thyroiditis
and blood pressure vary from high to veruìy low
she has cardiovascular disease familiarity
please help me
I checked for some genetic mutation but I can't find anything
thanks
Domenica
Inviare a
Am J Hum Genet. 2020 mar 5; 106 (3): 327-337. doi: 10.1016 / j.ajhg.2020.01.017. Epub 2020, 13 febbraio.
Lo studio di associazione a livello del genoma per i livelli di vitamina D rivela 69 loci indipendenti.
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