Dr sprouse-- Endo saying that Vit D below 30 leads to 2nd hyperparathyroidism due to calcium absorption deficiency and downstream consequences of that condition leads to poor bone health. He agreed all the other outcomes don’t have good evidence. I think 30 is the recommendation from the endo society. MY RESPONSE Well just to be clear they are right and they are wrong Yes it MAY, key word is MAY (it’s a not a universal truth), cause a secondary hyperparathyroid. HOWEVER, as I am sure you have already thought, this is a lab value. WE DON’T CARE ABOUT LAB VALUES, we care about patients. We treat patients, not lab values. So realistically who cares!?!?!? They will say well we care because it leads to broken bones and fractures!?!?! Then say really?? Based on what data because in this trial of almost 700 women who underwent BMD testing at baseline and 2 years later there was no difference between vitamin d and placebo https://asbmr.onlinelibrary.wiley.com/doi/full/10.1002/jbmr.3958 And they will say yes but that showed no difference because those individuals already had baseline high vit. D And you say—OOOO so you think something magical happens at the cutoff of 30 that makes it so these patients now magically benefit from vit d And they will say “that is correct” And you say, “well what about this article that talks about the analytic and biological variance of vit d to be about 50%, which basically means that you need to see a 50% change to even say that there is a real difference and a lab value of 30 COULD actually mean the real number falls anywhere between about 19 and 41 because lab values are just point estimates but in all actually there are 95% CI that surround each lab value or point estimate.” “Thus shouldn’t this magical number actually be 41?” https://www.bmj.com/content/368/bmj.m149 They will say “I have no idea what you are talking about, all lab values are 100% accurate” (this is a really really hard concept for people to grasp) Then you say- “well that is really interesting because this study actually found those individuals with baseline enrollment vit d level of 30 actually had worse volumetric BMD when taking higher levels of vit d” https://jamanetwork.com/journals/jama/fullarticle/2748796 They will say something like “yes, but that didn’t have a true placebo group and we fail to observe the rule of dose measurement” (which basically says that if you give some that is good and with increasing doses you should see more of an effect, it was be quantifiable to the same amount of the dose increase but it will be quantifiably greater. Think of blood pressure pills, you get most bang for your buck on the lowest dose, higher doses give you more but it is not at the same rate) And you say “well I can see you are really stuck on this magical cutoff of 30 even though the lab measurement is variable and appears to be completely made up and you don’t believe in dose response BUT what about this article that took 260 women with vit levels between 8 and 26 and randomized them to vitamin d levels achieved above 30 (which ended up being 3500IU daily as baseline level was 22) for 3 years and found no difference in bone density between the placebo group and the vit d group” https://asbmr.onlinelibrary.wiley.com/doi/full/10.1002/jbmr.3521 They will say, “Yes, but Andrew that is only one study and you can’t look at one study” You then say, “O well what about this meta-analysis and SR in Lancet Endocrinology that looked at 81 RCT and over 53K people that found and I quote “Our findings suggest that vitamin D supplementation does not prevent fractures or falls, or have clinically meaningful effects on bone mineral density. There were no differences between the effects of higher and lower doses of vitamin D. There is little justification to use vitamin D supplements to maintain or improve musculoskeletal health. This co(continued)