To determine the levels of vitamin D in patients with pulmonary tuberculosis in Shenzhen and identify the influencing factors of vitamin D levels and key groups of vitamin D deficiency, so as to provide a scientific basis for tuberculosis- and nutrition-related health education and promotion in Shenzhen.

Patients with smear-positive pulmonary tuberculosis who were diagnosed in 2016 were selected as the research subjects. Their relevant information and blood samples were collected, and the sample pool was established according to the inclusion criteria. One hundred and twenty patients were selected based on simple random sampling, including 84 men (70.0%) and 36 women (30.0%). Blood 25-hydroxyvitamin D [25(OH)D] concentrations were measured using chemiluminescence technology. Vitamin D statuses in patients were statistically described, and vitamin D levels in patients with different characteristics were compared. Multivariate linear regression analysis was performed to identify important factors influencing vitamin D levels in patients.

Mean serum concentration of 25(OH)D in 120 patients was (40.2±16.0) nmol/L. There were 2 cases of vitamin D sufficiency (1.7%), 28 cases of vitamin D insufficiency (23.3%), and 90 cases of vitamin D deficiency (75.0%), of which 23 cases (19.2%) were of severe deficiency. 25(OH)D concentrations in patients with different lifestyles (indoors; indistinguishable indoors or outdoors; outdoors) were significantly different (35.3 nmol/L vs. 40.6 nmol/L vs. 49.5 nmol/L, F=8.274, P<0.001). Mean concentration of 25(OH)D in patients with sun exposure time of >30 min/d was higher compared to that in those with sun exposure time <30 min/d in the last month (46.4 nmol/L vs. 36.7 nmol/L, t=3.342, P=0.001). Multivariate linear regression analysis showed that the risk factors for 25(OH)D with statistical significance were Han ethnicity or not (β=-11.576, t=-1.991, P=0.049), housekeeping (including unemployment and retirement) or not (β=-6.136, t=-1.998, P=0.048), sun exposure time<30 min/d or none (β=-9.644, t=-2.829, P=0.006), body mass index (β=-2.056, t=-3.439, P=0.001) , and indoor degree of lifestyles (β=-4.419, t=-2.155, P=0.033).

Level of vitamin D is generally insufficient in patients with pulmonary tuberculosis in Shenzhen. It is necessary to strengthen health education related to vitamin D in patients with tuberculosis, especially in the high-risk population of vitamin D deficiency, such as in those with a lack of exposure to sunlight or high BMI.

Tuberculosis; Pulmonary; Vitamin D deficiency; 25-Hydroxyvitamin D