Tuesday May 7, 2013
Well, having take on the non-controversial topic of PSA testing (pause here for laughter at my sarcasm) last week, let's look in on another area of full agreement(another pause): vit D & calcium supplementation in post - menopausal females.
Let's look at the data, first. There IS evidence supplementing post - menopausal women with 1000 mg elemental calcium AND at least 400 U vit D daily DOES lessen the risk of fractures. There is further evidenc showing dosing less than 1,000 mg elemental calcium AND < 400 U vit D have NO impact on lessening fractures in post - menopausal females.
Now, go back and read that carefully...in post - menopausal women (OK...), 1,000 mg calcium and 400 U vit D work to lessen the risk of fractures. There are NO trials showing higher doses or either calcium or vit D further lessen the risk.
So, it's NOT one of those things were some is good and more is better. The RIGHT amount is good and more is NOT better...in fact, mega - dosing with vit D (or vit A) is a not infrequent cause of abnormal liver function tests. Again, repeating...MORE VIT D IS NOT BETTER....at least according to scientific, randomized controlled trials.
All of this info is from a recent release from the U. S. Preventive Services Task Force (USPFT)...yes, the same folks that recommended discontinuing routine mammograms and all PSA testing. So, as you can imagine, I read their recommendations with a bit of a jaundiced eye.
Anyway, they are right about what the data shows. However, I think elevating vit D levels at least above 30 nmol/L (maybe that number is really 35) is a good idea and that may take more than 1,000 U daily, but only very rarely.
As you have probably read, the publicists for vit D supplementation have been very active, proposing that it improves atherosclerosis outcomes and other feats....however, not a scintilla of an iota of evidence exists for any such claims. And, I agree with USPFT that 1,000 mg of calcium is nearly always enough and I generally (for easy of administration) tell folks, 1,000 U vit D daily is the right dose (provided it gets the patient's vit D level > at least 30 nmol/L), buit if they can find 800 U bottles, I am fine with that.
Well, OK, what should men and pre - menopausal women do? There is NO significant amount of data on either group to know what recommendations, if any, to make.
So, let's review: in post-menopausal women only: 1,000 mg elemental calcium daily (rarely 1,500) + 400 - 1,000 U vit D daily. Younger women and men...I don't know, but if you look at risk to me for osteoporosis (i.e., 72-yr. old skinny white guy, former smoker), I'll probably check your vit D level and consider a Bone Mineral Density scan on you.
So, that's what I think. I can guarantee you will hear dissenting views. I tried to base mine upon the evidence. You might ask the dissenters what they are basing their recommendations upon...
If the data changes (i.e., I change my mind), I will let you know.