Olfactory function and vitamin D
Reviewed by Sunil Sharma

This Turkish prospective study evaluated olfactory function in individuals with primary vitamin D deficiency and the effect of replacement therapy on olfactory function over an eight-month period in 2019. A total of 91 individuals with vitamin D insufficiency were included, and 91 individuals with normal vitamin D levels as controls. Olfactory function was measured with the Connecticut Chemosensory Clinical Research Centre (CCCRC) test before and after vitamin D replacement therapy (12 weeks post-replacement). The mean 25-hydroxy vitamin D levels in the pre-replacement, control, and post-replacement groups were 12.88±5.90, 35.76±6.13, and 42.99±4.89 ng/mL, respectively. In the post-replacement group, mean threshold test scores (pre-replacement 3.75±1.2; 12th week post-replacement 5.29±1.02), mean identification test scores (pre-replacement 6.6±0.85; 12th week post-replacement 6.94±0.22), and mean total test scores (pre-replacement 5.17±0.89; 12th week post-replacement 6.12±0.54) demonstrated statistically significant increases when compared with the pre-replacement group (p<0.001). The mean total test scores of the pre-replacement group were significantly lower than the control group (p<0.001). There was no considerable difference statistically between the mean total test scores of the post-replacement and control groups (p=0.4). The results suggest that low blood vitamin D levels may be associated with olfactory dysfunction, and that vitamin D replacement therapy in those with vitamin D insufficiency can improve olfactory function.

Effect of vitamin D on olfactory function.
Baki A, Yildiz M, Gundogar S.
B-ENT
2021;17:86-91