Chinellato L, et al. - In a pediatric population with asthma, researchers investigated the link between vitamin D serum levels, pulmonary function, asthma control, and passive smoking exposure. In children with asthma who lived in a Mediterranean country, hypovitaminosis D was frequently detected. Lower levels of vitamin D were found to be related to attenuated asthma control and passive smoking exposure in these children.

Methods

• A cross-sectional study was carried out during the winter and early spring, wherein, researchers examined the link between 25-hydroxy cholecalciferol (25[OH]D) concentrations and baseline spirometry and levels of asthma control, and the impact of parental tobacco smoke exposure in 152 white children (84 boys [55.3%]) with a mean age ± standard deviation of 9.9 ± 2.0 years (range 5-15 years).

Results

• A sufficient serum 25(OH)D level (at least 30-40 ng/mL) was detected in only 9.9% of the children.
• The force vital capacity % predicted, forced expiratory volume in the first second of expiration % predicted, and serum 25(OH)D level (r = 0.36, p < 0.001 for both) were found to be positively correlated in a significant manner.
• Higher serum levels of 25(OH)D were detected in subjects with controlled asthma vs children with partially controlled or noncontrolled asthma, both according to Global Initiative for Asthma parameters and the Test for the control of asthma in childhood (p=0.011).
• Presentation with significantly higher serum levels of 25(OH)D was seen in children with both nonsmoking parents vs children with both smoking parents (median, 20.5 ng/mL [interquartile range {IQR}, 16.6-24.0 ng/mL] vs median, 14.5 ng/mL [IQR, 11.1-19.1 ng/mL], respectively; p < 0.001), with intermediate values for children exposed to single maternal (median, 20.3 ng/mL [IQR, 13.0-23.2 ng/mL]) or to paternal smoking (median, 17.8 ng/mL [IQR, 14.7-22.1 ng/mL]).