This is not a controlled study that will allow you to make inferences about causation.
Just because some groups do more of one thing doesn’t mean it causes any outcome. Example - people with arthritis take more aspirin. You can’t conclude that it’s the aspirin causing the dementia.
BTW recent studies in the New England Journal found no effect of supplement of Vitamin D in terms of osteoporosis or colon cancer. That’s in the general population. There may be some people for whom it is beneficial. It can’t hurt.
I just posted a link about excess retinol possibly causing osteoporosis in another thread.