Effectiveness of vitamin D supplementation on knee osteoarthritis - A target trial emulation study using data from the Osteoarthritis Initiative cohort.

What Was Tested

Researchers studied Vitamin D, K2, Magnesium and Zinc in this observational study publication.

Standardized mean difference (SMD) was used to compare the findings with previous RCTs.

Who Took Part

Eligible participants were ≥45 years, had symptomatic KOA and did not take vitamin D supplements in the past 30 days.

A participant can enter the trial more than once.

How the Study Was Run

The researchers set it up as a randomized study.

Random assignment meant chance, not the researchers, decided who got Vitamin D, K2, Magnesium and Zinc and who got the comparison, which limits bias.

This study emulated a target trial using data from the Osteoarthritis Initiative (OAI).

The control group did not use vitamin D in the past 30 days.

Optimal propensity score matching at 1:1 ratio was performed.

The primary outcome was change in knee pain 2 years after baseline measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

Secondary outcomes included WOMAC physical function and quantitative joint space width (JSW).

What Was Measured

PubMed files the paper under topics including Dietary Supplements, Knee Joint, Osteoarthritis, Knee, Pain, Vitamin D, Vitamins and Randomized Controlled Trials as Topic.

The authors tagged it with the keywords Causal inference.

What This Means in Plain Language

The paper is a randomized study of Vitamin D, K2, Magnesium and Zinc.

Results are reported in around 5 sentences of the abstract; we leave them to the paper itself rather than summarise them.

The publication is from 2022 (Osteoarthritis and cartilage), a journal based in England.

More context: the Vitamin D, K2, Magnesium and Zinc compound page, all human trials.