The level of vitamin D levels depends on the severity of asthma and age of onset.

This study aimed to assess the levels of vitamin D in patients with asthma, taking into account their body mass index (BMI), age of onset, and clinical characteristics. <bold>Methods.</bold> The study involved 553 people with asthma and 95 healthy individuals who agreed to participate in the study. To assess vitamin D content based on BMI, patients were categorized into 3 groups: Group I: 152 patients with normal body weight (NBW), Group II: 206 overweight patients, and Group III: 195 patients with obesity. Two groups were formed for analysis based on age of onset: 271 patients in the early-onset asthma group (including 100 obese patients) and 282 patients in the late-onset asthma group (including 95 obese patients). The results. A study showed that vitamin D levels in asthma patients (31.9 ± 0.62) were lower than controls(43.1 ± 1.04 ng/ml, p=0.001). Asthma patients with obesity had lower levels of vitamin D (25.1 ± 0.83 ng/ml) than those who were overweight or of normal weight (35.1 ± 1.25 ng/ml and 35.9 ± 0.96 ng/ml, respectively). Patients with an early onset have lower levels of vitamin D, (27.1 ± 0.86) ng/ml compared to those with late-onset asthma (36.4 ± 0.78) ng/ml (p = 0.001). Patients with a severe course of asthma have an average of (24.7 ± 0.71) ng/ml of vitamin D compared to those with a mild course, who have an average of (39.8 ± 0.78) ng/ml. Patients with asthma for more than 20 years have an average of (26.6 ± 1.20) ng/ml of vitamin D, compared to those with a shorter duration. <bold>Conclusions:</bold> Asthma patients generally have lower levels of vitamin D than controls. Obese asthma patients have lower vitamin D levels, as well as patients with early-onset and long-term asthma.