By Dr Stephen Ward · Website article published 17 October 2026 · Research published 2025
Could an everyday viral infection help explain why some people develop persistent back pain? This question led to a research collaboration between Dr Stephen Ward and the team associated with TwinsUK at King’s College London.
From a clinical question to a research study
Dr Ward proposed the original research question and worked with Professor Frances Williams and colleagues to investigate it. Published in JOR Spine in 2025, the study used UK Biobank data. Despite the researchers’ TwinsUK connection, this was not a study of twins or a treatment trial.
What did the study find?
Among 5,140 participants, evidence of previous cytomegalovirus (CMV) infection was associated with chronic back pain. The team also used genetic differences linked to CMV antibody positivity to explore whether the relationship might be causal—a method called Mendelian randomization.
The principal genetic analysis found a modest association: an odds ratio of 1.15, with a 95% confidence interval of 1.005–1.317. A second analysis using a combined genetic score also supported a link. These estimates are not an individual patient’s probability of developing pain.
What remains uncertain?
The genetic discovery sample was relatively small, requiring a less stringent threshold for selecting variants. Using the same dataset also raises concerns about overfitting and bias. The second analysis was not independent confirmation in a new population.
The proposed biological explanation—that CMV might affect fatty tissue around the muscles supporting the spine—remains a hypothesis. The study did not demonstrate that mechanism.
What does this mean for patients?
My assessment: This is an interesting lead that deserves independent replication. It broadens the questions we can ask about persistent back pain, but does not establish that CMV is causing a particular person’s symptoms.
The study did not test antiviral treatment. In my view, it does not justify routine CMV testing or antiviral prescribing for ordinary chronic back pain. A positive antibody result alone would not identify the source of someone’s pain. Care should continue to centre on an individual clinical assessment and treatments supported by appropriate evidence.
Original research
Naeini MK, Freidin MB, Smith IG, Ward S, Williams FMK. Evidence for a Causal Association Between Human Cytomegalovirus Infection and Chronic Back Pain: A One-Sample Mendelian Randomization Study. JOR Spine. 2025;8:e70063. Published online 8 April 2025.
Read the original paper ↗ · Read the open-access full text ↗
Author involvement: Dr Ward is a co-author, with contributions to study design and manuscript drafting. This article is his interpretation of research in which he participated.