March 11, 2019Pulmonology
According to the Centers for Disease Control and Prevention, one in 12 children in the U.S. have asthma, which totals 6.1 million children nationally. Additionally, asthma disproportionately impacts urban minority populations, such as black children. Higher indoor air pollution, from sources such as cigarette smoke, cooking, burning of candles, and incense, is linked to greater respiratory problems, including worsening of asthma symptoms and more hospital visits.
According to a study, published online in The Journal of Allergy and Clinical Immunology: In Practice (11 February 2019), vitamin D may be protective among asthmatic obese children living in urban environments with high indoor air pollution. The study identified many factors that make children susceptible to health problems from air pollution throughout Baltimore's inner city. The authors explained that at the time the study was being conceived, researchers were seeing vitamin D deficiencies across the U.S. It also had becoming clear that African-Americans were at higher risk for vitamin D deficiency, particularly black children. The authors deduced that since they were also noticing a heavy burden of asthma in inner city minority children, it seemed that there was a possibility that vitamin D deficiency and asthma were coincident and interacting in some way.
As a result, 120 school-aged children with preexisting asthma in the Baltimore area were studied evaluating 3 factors - air pollution levels in homes, blood vitamin D levels, and asthma symptoms. As a side note, one-third of the study participants were also obese. The children were evaluated at the start of the study and three times over the next nine months. Overall, results showed that having low blood vitamin D levels was related to the harmful respiratory effects of indoor air pollution among obese children with asthma. Conversely, in homes that had the highest indoor air pollution, higher blood vitamin D levels were linked to fewer asthma symptoms in obese children. According to the authors, what was most surprising was that the study showed the effects were most pronounced among obese children. The authors added that this highlights a third factor - the obesity epidemic - and helps bring that risk to light when considering individual susceptibility to asthma.
The authors indicated that one way to increase blood vitamin D levels is to increase sun exposure, but that isn't always possible in urban environments, or in people with darker skin pigmentation. Another way is through dietary supplements or eating more foods that are high in vitamin D, such as fatty fish, mushrooms, or foods fortified with vitamin D, such as bread, orange juice, or milk.