I'm taking Vitamin D3 + K2 (MK4 + MK7 mix).
A Japanese study of 4,000 people with osteoporosis found a 50% drop in fractures at extremely high dosages of K2. D3 and K2 seem to work synergisticly together. There are suggestions that K2 reduces calcium transport for arteriosclerosis.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566462/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5494092/