What is the research about?
Chronic musculoskeletal pain (pain that persists ≥3 months) is a major public health issue, affecting 1.7 billion people globally. We do not fully understand why some people develop chronic musculoskeletal pain. It is possible that low vitamin D levels in the body could be a contributing factor. This research explored if low vitamin D levels are linked to chronic musculoskeletal pain in various body sites, even after accounting for the effects of many other factors that could influence the results.
What did the researchers do?
We investigated the link between blood vitamin D levels and chronic musculoskeletal pain using data from 349,221 people who participated in the UK Biobank study. The UK Biobank is a large (N >500,000) ongoing study that investigates how genetic, lifestyle, and environmental factors affect various medical conditions.
The UK Biobank measured vitamin D levels in the blood using a marker called 25-hydroxyvitamin D (25(OH)D). We grouped participants based on their vitamin D levels into four categories: severely deficient (<25.0 nmol/L), deficient (25.0 to 49.9 nmol/L), insufficient (50.0 to 74.9 nmol/L) and sufficient (≥75.0 nmol/L). We assessed whether participants had chronic musculoskeletal pain at any site, neck/shoulder, back, hip, knee, or widespread pain.
We examined the statistical relationship between vitamin D levels and the presence of chronic musculoskeletal pain at each site. We ran the analyses with and without adjusting for confounding factors that could influence the results (that is, factors associated with both low vitamin D and increased risk of chronic pain). These included sociodemographic factors (age, sex, BMI, education, ethnic background, socioeconomic status), lifestyle factors (smoking, alcohol consumption, physical activity, sleep disturbance, dietary consumption of oily fish, and consumption of fish oil supplements), depression and co-existing medical conditions.
What did the researchers find?
When only adjusting for age and sex, low vitamin D levels (insufficient, deficient, and severely deficient) were significantly associated with chronic pain in all the sites we tested. However, when we took into account all factors that could influence the results, these associations became weaker or disappeared for chronic regional musculoskeletal pain (pain at any site, neck/shoulder, back, hip and knee pain). Severe vitamin D deficiency was still significantly linked to chronic widespread pain, even after taking all confounding factors into account.
How can you use this research?
Our study suggests that vitamin D levels may not play a major role in chronic regional musculoskeletal pain. However, severe vitamin D deficiency may be associated with chronic widespread pain. This suggests that checking for vitamin D deficiency might not be needed when managing chronic regional musculoskeletal pain, and vitamin D supplementation may not help with this type of chronic pain. But use of vitamin D supplements in individuals with chronic widespread pain and severe vitamin D deficiency warrants further exploration.
What you need to know:
The findings of this research are relevant to anyone interested in understanding chronic musculoskeletal pain, especially health care professionals, researchers, policy makers, and people living with chronic musculoskeletal pain. The findings help us understand the potential role of vitamin D in chronic musculoskeletal pain.
However, it should be noted that this study used a cross-sectional design. This means that this study does not tell us if low vitamin D level causes chronic musculoskeletal pain (it could be the other way around, or there could be no causal relationship). Further, the study used data from participants mainly living in England who took part in the UK Biobank study. These participants tend to be wealthier and healthier than the average person in the UK. Therefore, our findings may not be applicable to everyone in the UK or in other countries.
About the researchers
Dr Yanfei Xie is a postdoctoral research fellow at the RECOVER Injury Research Centre, The University of Queensland. Her research interests are understanding the mechanisms behind musculoskeletal pain and injury, developing effective interventions, and implementing them in clinical practice.
Dr Scott Farrell is a Research Fellow and physiotherapist at RECOVER Injury Research Centre, The University of Queensland. His research investigates neurological, genetic and inflammatory mechanisms underpinning chronic musculoskeletal pain, with a particular focus on whiplash associated disorder.
Dr Nigel Armfield is a Senior Research Fellow at RECOVER Injury Research Centre, The University of Queensland. His work focusses on the epidemiology and burden of minor to moderate injuries, longitudinal data analyses of intervention trial data, population studies of health-related quality of life and chronic pain, and the potential of digital heath for assessment and intervention following injury.
Professor Michele Sterling is an NHMRC Leadership Fellow and program lead of the Improving health outcomes after musculoskeletal injury program at RECOVER Injury Research Centre. She is the director of the NHMRC Centre of Research Excellence in Better Health Outcomes for Compensable Injury. Her main focuses of research are the physiological and psychological factors underlying musculoskeletal pain and injury, the prediction of outcome following whiplash injury, and the clinical translation of research findings to clinical practice.
Citation
Xie, Yanfei, Farrell, Scott F, Armfield, Nigel and Sterling, Michele (2024). Serum vitamin D and chronic musculoskeletal pain: a cross-sectional study of 349,221 adults in the UK. The Journal of Pain 104557. doi: 10.1016/j.jpain.2024.104557
Keywords
25-hydroxyvitamin D, chronic pain, confounding effect
Contact information, acknowledgements
Dr Yanfei Xie – Postdoctoral Research Fellow, The University of Queensland (yanfei.xie@uq.edu.au)
This research has been conducted using the UK Biobank Resource under Application Number 69067. This work uses data provided by patients and collected by the National Health Service (NHS) as part of their care and support.
