Osteoporosis/Osteopenia

-2.7 is barely into the osteoporosis range, the level having been rather arbitrarily decided a few years ago by the WHO as -2.5. You should be able to reverse this through exercise, diet and supplements.  The Z score is only comparing you with others your age, the more useful score is the t-score which compares you with a healthy young adult.   

Add Vitamin K2 to your supplements, make sure you are getting a little extra magnesium to balance the calcium (foods or an Epsom salts soak will work) and I undertand that potassium is another important element we need to make sure is in our diet.  Eat lots of leafy greens, the best include kale, broccoli and collards.  

Weightbearing exercise, such as walking and Nordic walking will help.  I have taken up Nordic walking, tai chi, and wear a weighted walking vest.  These have all helped contribute to my improved bone density (from -2 to -1.6 in a year).  No osteoporosis meds needed!

Spine readings are often lower than the hip. What was your hip T-score? That is really the one they moan about most. 

You are a prime candidate for low bone density - you don't say how tall you are but I'm small (5' 1" and at 8st would almost disappear so you must be slender.

Anhaga has given you the basics - she's the diet and exercise bone protection expert!