The study, published in the Journal of Clinical Endocrinology & Metabolism (JCEM), investigated the association between vitamin D status and immune markers of inflammation in a large sample of older adults.
Led by Professor Sean (JJ) Strain from the University of Ulster, the Irish research team demonstrated significant associations between low vitamin D status and markers of inflammation (including the ratio of IL-6 to IL-10) within elderly adults.
“These findings suggest that an adequate vitamin D status may be required for optimal immune function, particularly within the older adult population,” wrote the team.
"Our data suggest vitamin D may be involved in maintaining the health of the immune system as well as the skeletal system," added study co-author Dr Mary Ward, also the University of Ulster. "This study is the first to find a connection between vitamin D levels and inflammation in a large sample of older individuals."
"The results indicate immune function may be compromised in older individuals with vitamin D deficiency," explained Ward. "Ensuring older individuals have optimal vitamin D levels may be a way to boost immune function in this population, but this needs to be confirmed through additional studies."
The team followed 957 Irish adults, all of whom were at least 60 years old, as part of their observational study investigating vitamin D levels and immune function biomarkers. They monitored blood serum 25-hydroxyvitamin D (25(OH)D) levels in addition to performing assays of serum cytokines including IL-6, TNF-alpha, IL-10, and C-reactive protein (CRP).
Participants who were vitamin D deficient were more likely to have high levels of these biomarkers, which are linked to cardiovascular disease and inflammatory conditions such as multiple sclerosis and rheumatoid arthritis, said the team.
“Concentrations of IL-6, CRP, and the ratios of IL-6 to IL-10 and CRP to IL-10 were significantly higher in individuals with deficient (<25 nmol/L) serum 25(OH)D compared with those with sufficient (>75 nmol/L) status after adjustment for age, sex, and body mass index (P < .05),” they wrote.
Vitamin D status was also found to be a significant predictor of the IL-6 to IL-10 cytokine ratio, with participants defined as deficient significantly more likely to have an IL-6 to IL-10 ratio greater than 2:1 when compared with those defined as sufficient, they added.
Source: Journal of Clinical Endocrinology & Metabolism
Published online ahead of print - study available here
“Vitamin D Deficiency Is Associated With Inflammation in Older Irish Adults”
Authors: E. Laird, H. McNulty, M. Ward, L. Hoey et al