This is a 9 months, randomized, single center, open-label, parallel-group study to compare the efficacy and safety parameters of vitamin D supplementation in vitamin D deficiency subjects in China.

This is a 9 months, randomized, single center, open-label, parallel-group study to compare the efficacy and safety parameters of vitamin D supplementation in vitamin D deficiency subjects in China.

Eligibility for participation will be determined by medical history, physical examination, and laboratory results obtained during a screening visit. About 300 subjects with vitamin D insufficiency or deficiency will be included in this study. All subjects will be given informed consent before starting any examination and test. The following data of all subject will be collected: liver and kidney function, HbA1c, fasting blood glucose, fasting lipid profile, serum calcium, serum phosphate, parathyroid hormone, 25-hydroxy vitamin D(25OHD), serum procollagen type I N propeptide, serum C-terminal telopeptide of type I collagen, s-CTX and muscle power and balance.

After baseline data are collected, eligible subjects will be randomized into each group at a 1:1 ratio (150 for control group and 150 for vitamin D supplementation group, less than 20% drop-off rate is acceptable for this study). The initial vitamin D doses will be based on 25OHD levels at basis, and this dosage may be changed according be the level of 25OHD until the end of this study.

All subjects in the control group will be followed every half year. All subjects in the vitamin D group will be followed by visiting clinic, and will be titrated their doses. Dose adjustment should be aimed at achieving the following 25OHD targets: 30ng/ml. If above 25OHD target has not been achieved, vitamin D dose should be adjusted. Clinic visit will be conducted 3 months later to collect information, such as serum calcium, 25OHD and adverse events.

Complicated examinations will be repeated again after 9 months treatments for both groups, including physical examination, liver and kidney function, HbA1c, fasting blood glucose, fasting lipid profile, serum calcium, serum phosphate, parathyroid hormone, 25-hydroxy vitamin D(25OHD), serum procollagen type I N propeptide, serum C-terminal telopeptide of type I collagen, s-CTX and muscle power and balance. Data will be collected and analyzed.

Inclusion Criteria:

1. Informed consent obtained before any trial-related activities. (Trial- related activities are any procedure that would not have been performed during normal management of the subject.)
2. 25OHD<30ng/ml

Exclusion Criteria:

1. Severe systemic disease (including severe heart, liver, kidney and lung diseases, severe infection, mental disorder and connective tissue disease)
2. Primary hyperparathyroidism, other bone disease, malabsorption and other chronic gastrointestinal disease.
3. Pregnant, breast-feeding or the intention of becoming pregnant or not using adequate contraceptive measures.
4. Use of systemic or inhaled glucocorticoids or other medication known to interfere with bone metabolism.
5. Use of vitamin D related agents in recent 3 months.