Abstract
Background: Vitamin D deficiency is a worldwide health problem associated with various health complications. This study aimed to determine the prevalence of vitamin D supplementation in the Czech Republic, understand reasons for supplementation, and assess participants' knowledge of vitamin D's physiological effects. Methods: The study included 1812 participants representing the Czech population aged 15+, stratified by gender, age, and regional distribution. Data analysis was performed using SASD 1.5.8, using chi(2) independence tests and regression analysis. Results: The results revealed that only 13.5% of the participants maintained regular year-round vitamin D supplementation, while 51.5% never supplemented. A slight increase in supplementation was observed during the pandemic (2020-2021). Supplementation patterns were influenced by socioeconomic factors including age, gender, marital status, income, employment, and education (p > 0.001). Regarding vitamin D knowledge, 67.5% and 65.6% of participants recognized its role in immune system modulation and bone health, respectively. There were minor misconceptions, with 1.4% believing that it aggravates allergies and 1.8% linking it to cancer. Knowledge levels varied with education and residence size. Conclusions: Despite the high prevalence of vitamin D deficiency in the Czech population, regular supplementation remains low, indicating the need for enhanced prevention programs and awareness campaigns.