What causes low vitamin d levels and high alkaline phosphatase?

Vitamin D insufficiency/deficiency can be caused by low Vitamin D intake (by diet or lack of sunlight). A high alkaline phosphatase has a broad differential: Liver problems, gallstone obstruction, pancreatitis, pregnancy, hyperthyroidism, hyperparathyroidism, diabetes, healing fractures, cancer, infection, heart failure. Test results need to be taken in clinical context

Alkaline phosphate can also be broken down to liver or bone origins, but a low vitamin D level favors bone pathology.