Vitamin D and Diabetes in Older Adults

Many institutionalized elderly persons are at risk of vitamin D deficiency. This is due in large part by a lack of exposure to daily sunlight, but among older adults, chronic kidney disease, renal disorders, hypoparathyroidism, and other disorders can also predispose elderly persons to vitamin D deficiency. As vitamin D is important to the functioning of many of the body’s organ systems, deficiency has been associated with numerous poor health outcomes, including cognitive impairment, hypertension, osteomalacia leading to osteoporosis, and weakness leading to higher risk of falls and fracture, among other problems. A recent study published in the Journal of the American Geriatrics Society reveals that vitamin D deficiency may also be associated with type 2 diabetes.

Researchers based in Australia conducted a population-based, cross-sectional analysis of 1,659 community-dwelling men aged 70 years and older who were included in CHAMP, a large epidemiological study conducted in Sydney between January 2005 and May 2007. The study examined the men’s levels of 25-hydroxyvitamin D (25OHD) and the active vitamin D metabolite, 1,25-hydroxyvitamin D (1,25OHD, also known as calcitrol). Data on other factors were also collected, including presence of diabetes mellitus, amount of sun exposure, body mass index, vitamin D supplement use, statin use, depression, ability level in activities of daily living, parathyroid hormone level, and estimated glomerular filtration rate.

Diabetes mellitus type 2 was prevalent in 20% of the study population. The researchers found that there was a significant association between diabetes and low 25OHD and 1,25OHD levels that remained even after adjusting for confounders and covariates, including comorbidities, renal function, calciotropic hormones, and medications.

Based on these findings, the investigators concluded in their study that, “The independent association between serum 25OH and 1,25OHD concentrations and [diabetes mellitus] raises the question of whether each of the two vitamin D metabolites may influence [diabetes mellitus] through different biological mechanisms and pathways.”

These findings are in line with previous observational studies suggesting that low vitamin D intake predisposes adults to both type 1 and type 2 diabetes. Additionally, previous studies have suggested that low vitamin D levels may increase the risk of cardiovascular events in adults with diabetes compared with adults without diabetes.  The mechanisms by which vitamin D influences the onset or progression of diabetes is still under investigation.

-Allison Musante