What happens if we don't get enough vitamin d every day?

Osteoporosis: Bone health depends upon vitamin D. Calcium levels, too. Parathyroid hormone (PTH) depends upon vitamin D to regulate calcium levels. While there is some evidence that vitamin D affects more than bone health, that evidence, while plentiful, isn't of the highest quality eg randomized controlled trials. Everyone agrees that normal 25OH D is more than 30ng/mL. But we disagree as to benefit if higher