Prevalence of vitamin D deficiency in seniors - A retrospective study

Vitamin D deficiency is a condition with different causes. It is associated with numerous comorbidities such as autoimmune diseases, bone diseases, cancer, cardiovascular diseases, neurodegenerative diseases, psychiatric diseases, and respiratory infections like COVID-19. Due to its high prevalence all over the world, it is a major task for health care systems worldwide. Through a combination of low sunlight exposure, insufficient nutrition, and age-related changes in skin, liver, and kidney function, especially seniors and nursing home residents, in particular, have a significantly increased risk of developing a vitamin D deficiency.

This retrospective study analyzed the prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D] < 12 ng/ml) amongst selected Austrian nursing home seniors. It also examined whether demographic data and other laboratory values like calcium correlate with vitamin D levels by using the Pearson correlation coefficient. This correlation was graphically illustrated with a scatter plot and regression line. A total of 478 patients admitted to a nursing home in Vienna between January 3, 2017, and August 31, 2020, were included.

A total of 106 seniors (22,2%) suffered from a manifest vitamin D deficiency. The vitamin D level of the men was significantly lower than the level of the women (22.9 ± 12.6 ng/ml vs. 26.2 ± 14.8 ng/ml, p = 0.027). The vitamin D serum levels significantly correlated with the serum calcium levels of the participants (r = 0.19, p < 0.001). 39.5% (189 out of 478) of the nursing home residents had inadequate serum vitamin D levels.

In summary, it can be said that the prevalence of vitamin D deficiency among nursing home residents is considerably high. Inadequate vitamin D levels were often associated with reduced calcium levels. Given the high prevalence, the numerous negative health consequences of inadequate levels, and the large therapeutic index, this risk group should get a general supplementation with a dose of 25 μg (1000 IU) vitamin D3 per day. In addition, a blood examination should be performed as early as three months after the start of the supplementation therapy. If some residents do not achieve an adequate vitamin D concentration, the substitution has to be adapted to the individual needs to treat them as precisely as possible.