The trial plan to determine whether a daily capsule containing vitamin D(3) (2000 IU), calcium (600 mg), both, or a placebo for 6 months in UAE citizens with evidence of vitamin D deficiency will lead to a clinical benefit. The proposed study will also determine the threshold of vitamin D and calcium intake or levels considered optimal for UAE citizen's health

The proposed study is a two by two factorial, randomized controlled intervention trial. Following informed written consent of eligible subject's blood and urine samples will be taken for measurements of vitamin D, markers of bone turnover and related biochemical variables. Patients who have evidence of vitamin D deficiency will then be randomly assigned to receive daily vitamin D(3) (2000 IU), calcium (1000 mg), both, or a placebo for 6 months. All subjects will have a calcium and vitamin D rich food and other lifestyle modification advises during the study period. Patients will otherwise be managed according to standard practice. Clinical assessment that includes general and self-rated health, bone density, muscle strength, physical activity and dietary intakes will be performed at baseline, and repeated at 3, 6 and 12 months post-randomisation.

Information on other important variables likely to influence vitamin D status including age, reproductive & menopausal history, smoking, medications, adiposity, exposure to sunlight, dietary intake including supplements, skin pigmentation, chronic illness and medications will be collected and adjusted for during the analysis

Inclusion Criteria:

1. biochemical evidence of vitamin D deficiency

Exclusion Criteria:

1. renal disease or stones or hypercalcaemia,
2. Use of calcium and/or vitamin D supplementation, bisphosphonates, steroid medications, hormones or diuretics.

Double blind