I took a bone scan almost 10years ago and the result was osteoperenia eventhough i always drink milk since my childhood. what are the causes of it?

Keep drinking milk: There are many causes for osteopenia and they can include chronic diseases, smoking, low vitamin D levels and low physical activity. Calcium and vitamin D are found in milk but you may still need more than what you can drink in milk alone. If you are concerned I would recommend talking to your doctor to see if you need to recheck your bone density or not- especially if you have risk factors.