I changed machines time before last (didn't know I shouldn't) It was still Yale hospital but a satellite. That said, I went from -2.9 in spine according to new place to -2.1 back to main hospital a year later. Other parts were osteopenia but not bad. How much can error be?
What I did inbetween was lift heavier, 5-6 days a week, concentrating on back and hips. I upped protein when I could, took Thera Cal which had calcium, Vit K2, Magnesium and boron and I took the one with Vit D 2000 since my doc wanted that. I'm lactose intollerant but ate more greek yogurt, oranges, veggies etc but the biggest change was supplements and working out much harder. I also bought weighted vest but only used it walking once or twice a week once summer hit. I sometimes I use it for squats etc. It took me 5 months to work up to 10bs (hyperwear vest)
So the next Dexa will be interesting but I'm glad my doc is conservative and said "no meds" for now. This way changes are more holisitic and not medical. I'm 63.