Abstract Introduction Allergic rhinitis is one of the most common allergic diseases that cause a decrease in quality of life. Over the last decades, the increase in the number of cases is supposed to be a result of industrialization and lifestyle changes. Vitamin D, which is a steroid hormone, has a significant immunomodulatory and antioxidant role in the human body. Objective The objective of the present study is to investigate the role of 1α-25-dihydroxyvitamin D3 levels in allergic rhinitis patients and to compare them to the levels found in the healthy population. Methods A total of 256 participants were included in the present study. Allergic rhinitis is diagnosed with the help of the Allergic Rhinitis and Its Impact on Asthma (ARIA) guidelines confirmed through skin prick tests. Control subjects were selected among people without allergy history, which was also confirmed through skin prick tests. The levels of 1α-25-dihydroxyvitamin D3, immunoglobulin E (IgE), and eosinophil counts were measured in blood samples from both groups. Results The mean value of serum levels of 1α-25-hydroxyvitamin D3 was 25.5 ± 3.74 in the allergic rhinitis group, and 31.58 ± 3.85 in the control subjects. This difference reveals statistically-decreased levels in the allergic rhinitis group (p< 0.05). The total IgE levels are increased in the allergic rhinitis group (p< 0.05) and negatively correlated with the serum levels of 1α-25-hydroxyvitamin D3 (r = - 0.259, p< 0.05). Conclusion Lower serum levels of 1α-25-hydroxyvitamin D3 were detected in the allergic rhinitis population. This data is also correlated to the IgE response in the study group. A supplement of 1α-25-hydroxyvitamin D3 in deficient patients might be helpful to relieve symptoms and signs of allergic rhinitis, but further studies are needed.

Abstract Introduction Noise-induced hearing loss (NIHL), which is one of the most common occupational diseases among industrialized populations, is associated with longstanding exposure to high levels of noise. The pathogenesis of NIHL is not clear, but some genes and their activity at the tissue level have been investigated. Hypercholesterolemia, which can disturb the microcirculation, can be one of the underlying pathologies in hearing loss. Objective To investigate the relationship between NIHL and hypercholesterolemia. Methods The study group was selected among workers who had an occupational exposure of 85 dB of noise for at least 10 years. The audiologic assessment was recorded at seven frequencies (500 Hz, 1,000 Hz, 2,000 Hz, 3,000 Hz, 4,000 Hz, 6,000 Hz and 8,000 Hz). A total of 456 workers were included in the study and divided into two groups: the control group (252 patients) and the NIHL group (204 patients). After the audiologic measurement, blood samples were taken and investigated for blood cholesterol levels. According to these results, the groups were compared. Results Both groups were similarly distributed regarding age and occupational exposure time (p > 0.05). We could not detect any association between cholesterol levels and noise-induced hearing loss (p < 0.05). According to logistic regression analyses, the odds ratios are not significant for both hypercholesterolemia and hypertriglyceridemia (p > 0.05). Conclusion Noise-induced hearing loss is still a common occupational problem that can be prevented by hearing conservation programs and occupational health and safety training. Still, we know little about the relationship between NIHL and hypercholesterolemia. According to our findings, we cannot detect any relationship. Controlled studies and studies with human individuals can be made possible in the future with diagnostic innovations in tissue imaging and tissuemicrocircular sampling.