Table 2 Primary outcome analysis

To determine the response of vitamin D₃ dose on fracture healing at 3 months

High doses of supplementation (loading or daily) will increase healing compared to low daily dose. Using high doses will rapidly increase the circulating vitamin D available during fracture callus formation.

1. FIX-IT (clinical)

Patients in the high loading dose and high daily dose groups will be combined for a 2:1 comparison against low daily dose group using an independent t-test (alpha = 0.20).*

2. RUST (radiographic)

3. PINP (biologic)

4. CTX (biologic)

To determine the response of vitamin D₃ frequency on fracture healing at 3 months

High loading dose increases healing compared to high daily dose. Loading doses will overcome medication adherence issues and increase circulating vitamin D even more rapidly than daily doses.

1. FIX-IT (clinical)

Comparisons between the high loading dose and high daily dose groups will be made using an independent t-test (alpha = 0.20).*

2. RUST (radiographic)

3. PINP (biologic)

4. CTX (biologic)

To determine the response of low amounts of vitamin D₃ supplementation on fracture healing at 3 months

Low daily dose will increase healing compared to placebo. While the low daily dose is not expected to increase circulating vitamin D as rapidly as the high dose strategies, this comparison will determine if rapid serum increases are necessary to improve fracture healing.

1. FIX-IT (clinical)

Comparisons between the low daily dose and placebo groups will be made using an independent t-test (alpha = 0.20).*

2. RUST (radiographic)

3. PINP (biologic)

4. CTX (biologic)