Background
Vitamin D deficiency is a significant public health problem worldwide since vitamin D is essential for the health of the musculoskeletal system, muscle function, and bone mineralization. Studies have reported that over 90% of patients with disorders associated with the musculoskeletal system have low levels of 25-hydroxyvitamin D, which is the standard and most accurate method of measuring the concentration of vitamin D in the body. Vitamin D also plays an anti-inflammatory role and helps modulate pain. Therefore, individuals with low vitamin D levels in the serum often suffer from various conditions involving chronic pain.
Of the many chronic pain conditions, lower back pain is believed to be the one linked to the most years lived with disability across the world. Health statistics from 2017 indicate that close to 8% of the global population suffers from lower back pain, and the number is rapidly rising. While various factors such as injuries, sedentary lifestyles, genetics, occupational causes, and psychosocial issues can contribute to lower back pain, the role of vitamin D in alleviating lower back pain remains largely unexplored.
About the study
In the present study, the researchers used a substantial cohort from the U.K. Biobank to examine whether the levels of 25-hydroxyvitamin D or vitamin D supplementation were associated with lower back pain using longitudinal and cross-sectional data.
The participants consisted of adults between the ages of 40 and 69 who were recruited across centers in Scotland, England, and Wales. Their biomedical information was obtained through multiple methods, including questionnaires, interviews, functional and physical evaluations, and clinical analyses of saliva, urine, and blood samples.
Vitamin D status was decided based on the serum levels of 25-hydroxyvitamin D, with deficiency defined as 25-hydroxyvitamin D levels below 30 nmol per liter, while concentrations between 30 and 50 nmol per liter being considered as vitamin D insufficiency. Serum 25-hydroxyvitamin D levels above 50 nmol per liter were considered sufficient. Baseline visit questionnaires provided the researchers with data on the use of multivitamins and vitamin D supplements.
The primary care records were used to obtain information on lower back pain diagnoses and diagnosis dates. The baseline visit diagnoses were used for the cross-sectional analysis, while lower back pain cases diagnosed during follow-ups were used for the longitudinal analysis. Questionnaires were also used to determine self-reported lower back pain, and this data was combined with physicians’ diagnoses of lower back pain to determine the exposure variable.