Firstly, as the original poster, I reported this thread of two years ago, due to the spam post offering vitamins online, which came before BlueSky's post.
For those of us who suffer from osteoporosis and are unable to take oral biophosphates, it is essential for doctors check Vitamin D levels, before administering an Alendronic acid infusion. This is done annually, prior to the treatment being administered.
This infusion can leach Vitamin D from the body, so it is essential to check Vit D levels before commencing treatment.
In my case, the levels didn't register at all, so I had a very high dose course of Vitamin D, prescribed by an endocrinologist for I received an infusion.
Low levels of Vitamin D can cause:
Increased risk of death from cardiovascular disease
Cognitive impairment in older adults
Severe asthma in children
Cancer
For some reason, my body wasn't storing Vitamin D.
Being faired skinned, red haired and living in northern climate with little sunshine, probably contributed to this.