Hi, I got checked my vitamin D, two year back it was 16. Then I taken sachet of vitamin D for three month on weekly basis. Now I am taking it once in a month. Last year I was facing knee join problem. This year it OK. Kindly advise, do we need to take this dose on monthly basis. How often we need to get vitamin D Check. Can we give same treatment to family members as sun exposure is less due to nature of job. We used to take milk products on daily basis. Is any relation of Calcium and Vitamin D is there. Kindly suggest. Regards.