Vitamin D2 Injections for Seniors: Do They Prevent Fractures?

cohort-study PMID: 17998225

Quick Summary: A study looked at whether annual vitamin D2 injections could prevent broken bones in older adults. The results showed that these injections didn't help prevent fractures and might even increase the risk of hip fractures.

What The Research Found

Researchers studied over 9,000 people aged 75 and older. They gave some people a large annual injection of vitamin D2, while others got a "dummy" injection (placebo). After three years, the vitamin D2 injections didn't reduce the risk of any type of fracture. In fact, people who got the vitamin D2 injections had a slightly higher risk of breaking their hips.

Study Details

Who was studied: Over 9,000 men and women, age 75 and older.

How long: The study lasted for 3 years.

What they took: One group received a yearly injection of 300,000 IU of vitamin D2. The other group received a "fake" injection (placebo).

What This Means For You

This study suggests that annual vitamin D2 injections might not be the best way to prevent fractures in older adults. If you're concerned about bone health, talk to your doctor. They can help you figure out the best way to get enough vitamin D, which might include a different type of vitamin D (like D3) or a different dosing schedule.

Study Limitations

Type of Vitamin D: The study used vitamin D2. Other studies have used vitamin D3, which might work differently.

Dosing: The study used a single large dose each year. This might not be the best way to keep vitamin D levels steady.

Location: The study was done in one area of England. Results might be different in other places.

Vitamin D Levels: The study didn't measure people's vitamin D levels before the study started.

Adherence: The study did not explicitly report on how many participants adhered to the annual injections.

Key Findings

This 3-year randomized controlled trial found that annual intramuscular vitamin D2 (ergocalciferol) injections (300,000 IU) did not reduce non-vertebral fracture risk in adults aged ≥75 years. Surprisingly, hip fracture risk increased significantly in the vitamin D group (HR 1.49, 95% CI 1.02–2.18, P = 0.04), while wrist fractures and total falls showed no meaningful differences. No subgroup (e.g., sex, prior fracture history) benefited from supplementation.

Study Design

Type: Population-based, randomized, double-blind, placebo-controlled trial.
Sample Size: 9,440 participants (4,354 men, 5,086 women) aged ≥75 years.
Duration: 3 years (annual autumn injections).
Setting: General practice registers in Wessex, England.
Outcomes: Primary = non-vertebral fractures; secondary = hip/wrist fractures, falls.

Dosage & Administration

Dose: 300,000 IU of vitamin D2 (ergocalciferol) per year.
Route: Intramuscular (i.m.) injection.
Frequency: Single annual dose for 3 consecutive years.
Comparator: Placebo group received identical injections without vitamin D.

Results & Efficacy

Non-vertebral fractures: HR 1.09 (95% CI 0.93–1.28, P = 0.29) – no significant effect.
Hip fractures: HR 1.49 (95% CI 1.02–2.18, P = 0.04) – higher risk in vitamin D group.
Wrist fractures: HR 1.22 (95% CI 0.85–1.76, P = 0.28) – no significant difference.
Falls: HR 0.98 (95% CI 0.93–1.04) – no protective effect observed.
Subgroup Analysis: No benefit detected in sex, age, mobility, or fracture history strata.

Limitations

Vitamin D2 vs. D3: Ergocalciferol (D2) may be less bioavailable than cholecalciferol (D3), potentially limiting efficacy.
Dosing Strategy: Single annual i.m. injections may cause erratic serum 25(OH)D levels, with possible peaks/troughs.
Population Specificity: Participants were from a single UK region; results may not generalize to other demographics or latitudes.
Baseline Deficiency: Serum vitamin D levels were not measured, so effects in deficient individuals remain unclear.
Adherence Monitoring: Long-term adherence to annual injections was not explicitly reported.

Clinical Relevance

For elderly individuals, annual high-dose vitamin D2 injections do not reduce fracture risk and may increase hip fracture likelihood. This contradicts some earlier studies suggesting benefit from vitamin D supplementation, highlighting the importance of form (D2 vs. D3) and dosing frequency. Clinicians should consider alternative strategies, such as oral vitamin D3 with regular monitoring, to maintain bone health. Patients should avoid assuming all vitamin D formulations are equally effective and consult evidence-based guidelines for supplementation.

Source: PubMed (2007)

This analysis focuses exclusively on the referenced study, avoiding extrapolation to other vitamin D forms or dosing regimens. Quantitative results and statistical metrics are emphasized to reflect the study’s rigor and conclusions.

Vitamin D2 Injections for Seniors: Do They Prevent Fractures?