What I found is that women who are slightly further along in the process have elevated levels of serum alkaline phosphatase. This common marker done in laboratory tests can be utilized to indicate increased bone activity, and generally when you have increased bone activity you're going to have bone loss in the near future. Bone cell activity is a normal occurrence marked by the breaking down and rebuilding of bone at remodeling sites. When estrogen levels decrease after menopause, the remodeling rate increases, but the process of rebuilding the bone is not as efficient. That results in net loss of bone.
Alkaline phosphatase is attached to the outside of bone-forming cells called osteoblasts.
So, its levels rise with the increased bone activity. But alkaline phosphatase also can be found in other organ systems, Lukacs says. In order to be sure that the increased enzyme levels were a result of the bone activity, the study participants had fasted, eliminating the elevations in alkaline phosphatase that could occur in the intestines after a fatty meal. Lukacs checked other measures of liver function to ensure the alkaline phosphatase levels were not influenced by the liver. With those accounted for, the increase in production of alkaline phosphatase could be attributed to the increased bone activity, suggesting bone loss.