Here is my input:
-- Have your vitamin D 25(OH)D blood level checked, and see whether you're in the optimal range of 50 - 80 ng/mL. If yours is low (possible even with your sun exposure), supplement with vitamin D3 until you're in the optimal range. According to cillakat, the body requires significantly less calcium than the typically recommended daily RDA, if blood levels of Vit D are optimal.
-- I haven't personally been able to find the articles that cillakat has mentioned, but I do recall that *how* much less calcium is required, for people with optimal Vit D blood levels, has *not* yet been established, so it's anyone's guess. 600 mg/day? 200 mg/day? Personally, I prefer to err on the side of taking too much calcium rather than too little, so I personally would supplement with calcium citrate to bring yourself into the 1,000 mg/day range.
-- I highly recommend taking a good Vitamin K2 supplement. K2 is supposed to "direct" calcium to your bones instead of allowing calcification of blood vessels, so K2 is a crucial supplement for everyone, particularly since nobody is certain about how much Ca intake is ideal.
Here is an informative Mercola article on K2:
The 2 vitamin K2 products that I personally use are the following:
Jarrow MK-7, 90 mcg
Life Extension Foundation Super K (less expensive from iHerb... not appearing on iHerb's site at the moment, for some reason)