哮喘联盟

   摘要
   背景：美国城市儿童人群面临着不成比例的哮喘负担。最近的关注集中在维生素D的免疫抑制作用上，因为其可能对疾病发病有保护作用。由于人体维生素D水平主要决定于阳光暴露，我们旨在判断城市学龄前哮喘患儿25-OH维生素D水平是否偏低，低水平维生素D是否受户外活动时间影响以及是否与哮喘发病率有关。
   方法：我们对巴尔的摩和马里兰州121例队列中的城内哮喘儿童（2～6岁）的基线血清25-OH维生素D水平进行检测。对参与者纵向随访3个月和6个月，评估户外活动时间、哮喘症状（通过问卷和每日日记评估）和过敏标记物。
   结果：以黑人为主的学龄前儿童中， 25-OH维生素D的中位水平为28 ng/mL (IQR 21.2-36.9)，54%儿童低于传统足量水平（30 ng/mL），7.4%处于佝偻病风险范围(< 15 ng/mL)。中位户外活动时间为3小时/天(IQR 2--4)，并非户外活动时间越长，维生素D水平越高。在本研究人群中，25-OH维生素D未随着季节变化(p = 0.66)。低水平25-OH维生素D与高IgE水平相关。
   结论：城市非裔美国学龄前哮喘患儿维生素D缺乏率高，增加户外活动并不能纠正25-OH维生素D低水平。对于这类患者，可能还需要通过膳食补充来提高维生素D水平。
 

（苏楠 审校）
Nutr J. 2013 Jun 12;12(1):81. [Epub ahead of print]

 

Outdoor exposure and vitamin D levels in urban children with asthma.
 

Bose S, Breysse PN, McCormack MC, Hansel NN, Rusher RR, Matsui E, Peng R, Curtin-Brosnan J, Diette GB.
 

Abstract
BACKGROUND: The inner-city pediatric population in the United States has a disproportionate burden of asthma. Recent attention has focused on the immunomodulatory role of vitamin D, which may be protective against disease morbidity. As the primary determinant of vitamin D status in humans is exposure to sunlight, we aimed to determine if 25-OH vitamin D levels in urban preschool children with asthma were low, influenced by time spent outdoors, and associated with asthma morbidity.
METHODS: Serum 25-OH vitamin D levels were measured at baseline in a cohort of 121 inner-city children ages 2--6 years with asthma in Baltimore, MD. Participants were followed longitudinally at 3 and 6 months to assess time spent outdoors, asthma symptoms through questionnaires and daily diaries, and allergic markers.
RESULTS: In a predominantly black population of preschool children, the median 25-OH vitamin D level was 28 ng/mL (IQR 21.2-36.9), with 54% of the children below the traditionally sufficient level of 30 ng/mL and 7.4% in the range associated with risk of rickets (< 15 ng/mL). The median time spent outdoors was 3 hours/day (IQR 2--4), and greater time spent outdoors was not associated with higher vitamin D levels. 25-OH vitamin D did not show seasonal variation in our cohort (p = 0.66). Lower 25-OH levels were correlated with higher IgE levels.
CONCLUSIONS: Urban African-American preschool children with asthma have high rates of vitamin D insufficiency, and increased outdoor exposure is unlikely to correct these low 25-OH vitamin D levels. Repletion in this population may require dietary supplementation.
 

Nutr J. 2013 Jun 12;12(1):81. [Epub ahead of print]