PurposeIn the USA and Europe, hypovitaminosis D is associated with increased asthma severity, emergency department (ED) visit, and impaired pulmonary function in asthmatic patients. However, in tropical countries, data on the effect of vitamin D status on asthma is limited. This study evaluates the relationship between vitamin D status and the level of asthma control as well as other asthmatic parameters.MethodsAsthmatic children were evaluated for serum 25-hydroxyvitamin D, pulmonary function tests, a skin prick test, and the level of asthma control.ResultsA total of 125 asthmatic children were recruited (boys, 66.4%). Their mean age±SD was 10.8±3.0 years. Vitamin D statuses were: deficiency (<20 ng/mL) in 19.2% of the patients, insufficiency (20-30 ng/mL) in 44.8%, and sufficiency (>30 ng/mL) in 36%. The vitamin D levels were 25.9±9.4 ng/mL in uncontrolled patients, 29.2±8.6 ng/mL in partly controlled patients, and 27.9±8.0 ng/mL in controlled patients (P>0.05). There were no significant differences in pulmonary function, asthma exacerbation, inhaled-corticosteroid (ICS) dose, anti-inflammatory drugs, or ED visit or hospitalization between different vitamin D statuses. Vitamin D deficiency patients were older and had a delayed onset of asthma than insufficiency or sufficiency patients. There was no significant correlation between serum vitamin D and pulmonary function/doses of ICS.ConclusionsHigh prevalences of vitamin D deficiency and insufficiency were found in asthmatic children in Thailand; however, there was no significant relationship between vitamin D status and the level of asthma control or other asthma parameters.

BackgroundThere are limited data regarding the prevalence and risk factors relating to hypovitaminosis D in children of Thailand, a tropical country with abundant sunlight. The objective of this study was to assess the prevalence of hypovitaminosis D and examine factors associated with hypovitaminosis D in school-aged children in Bangkok, Thailand – a centrally located capital city.MethodsThis cross-sectional study evaluated 159 healthy children (33.3% boys and 66.7% girls), aged 6 to 12 years, in Bangkok, Thailand (located at 13.45°N). Fasting plasma samples were examined for total 25-hydroxyvitamin D [25(OH)D] using electrochemiluminescence immunoassay. Demographic characteristics (age, sex, household income), past medical history (birth weight, allergic diseases, hospitalization), amount of sun exposure, anthropometric data, and selected biochemical tests were used to investigate for factors associated with hypovitaminosis D.ResultsOverall, the mean ± SD level of plasma 25(OH)D was 64.0 ± 15.1 nmol/L. Hypovitaminosis D (< 75 nmol/L) was presented in 79.2% of subjects. Of these, the prevalence of vitamin D insufficiency and vitamin D deficiency were 59.7% and 19.5%, respectively. In univariate analysis, children with hypovitaminosis D (< 75 nmol/L) had a higher mean body mass index (BMI) percentile than the vitamin D-sufficient group (56.7 ± 33.9 vs. 42.6 ± 36.0; P-value = 0.04). Plasma PTH levels in the children with hypovitaminosis D were significantly higher than in the children with normal levels of vitamin D (4.34 ± 1.38 vs 3.78 ± 1.25 pmol/L; P-value = 0.04). In multivariate analysis, high BMI percentile and high PTH concentration were the parameters associated with 25(OH)D level < 75 nmol/L.ConclusionThe prevalence of hypovitaminosis D in healthy Thai children is very high, despite their exposure to sunlight, and that prevalence increases in children with a high BMI percentile. As a result, a formal recommendation for vitamin D supplementation in Thai children should be considered.

higher prevalence of hypovitaminosis D in asthmatics than in the normal population; in addition, low vitamin D levels are associated with a higher severity of asthma and impaired pulmonary function. 5,6 Patients with vitamin D deficiency have shown to have increased airway hyper-responsiveness and increased corticosteroid requirements. Vitamin D might increase the response to glucocorticoid in asthmatic patients. 7,8 In pregnancy, maternal vitamin D intake has an inverse correlation with risk of recurrent wheezing in childhood. The problems of vitamin D deficiency/insufficiency are in- Original ArticleAllergy Asthma Immunol Res. 2013 September;5(5):289-294. http://dx.doi.org/10. 4168/aair.2013.5.5.289 pISSN 2092-7355 • eISSN 2092 Purpose: In the USA and Europe, hypovitaminosis D is associated with increased asthma severity, emergency department (ED) visit, and impaired pulmonary function in asthmatic patients. However, in tropical countries, data on the effect of vitamin D status on asthma is limited. This study evaluates the relationship between vitamin D status and the level of asthma control as well as other asthmatic parameters. Methods: Asthmatic children were evaluated for serum 25-hydroxyvitamin D, pulmonary function tests, a skin prick test, and the level of asthma control. Results: A total of 125 asthmatic children were recruited (boys, 66.4%). Their mean age±SD was 10.8±3.0 years. Vitamin D statuses were: deficiency (<20 ng/mL) in 19.2% of the patients, insufficiency (20-30 ng/mL) in 44.8%, and sufficiency (>30 ng/mL) in 36%. The vitamin D levels were 25.9±9.4 ng/mL in uncontrolled patients, 29.2±8.6 ng/mL in partly controlled patients, and 27.9±8.0 ng/mL in controlled patients (P>0.05). There were no significant differences in pulmonary function, asthma exacerbation, inhaled-corticosteroid (ICS) dose, anti-inflammatory drugs, or ED visit or hospitalization between different vitamin D statuses. Vitamin D deficiency patients were older and had a delayed onset of asthma than insufficiency or sufficiency patients. There was no significant correlation between serum vitamin D and pulmonary function/doses of ICS. Conclusions: High prevalences of vitamin D deficiency and insufficiency were found in asthmatic children in Thailand; however, there was no significant relationship between vitamin D status and the level of asthma control or other asthma parameters.

Background The international and Thai asthma guidelines recommend stepping-down controller treatment in patients whose asthma symptoms have been controlled and maintained for 3 months or longer. After stepping-down treatment, some patients experienced exacerbations and required emergency care. There is limited understanding of stepping-down treatment for asthmatic children. The goal of this study was to determine the failure rate and associated factors after stepping-down treatment in pediatric asthma. Methods A retrospective study of electronic medical records of asthmatic patients aged between 3 and 15 years with controlled symptoms and indications for stepping-down treatment was conducted at Maharat Nakhon Ratchasima Hospital, a tertiary care center in Northeast Thailand, between January 2015 and December 2019. Results Of the 110 asthmatic patients with well-controlled asthma who received stepping-down treatment, 90 patients were followed over 12 months. Failure of treatment within 12 months of follow-up was 37.8% (34 of 90). Patients who failed to stepping-down treatment had asthma onset at a younger age (p = 0.026) and less than 9 months duration of asthma stability before stepping-down (p = 0.049). In multivariate analysis, the factor associated with failed stepping-down treatment was the length of asthma stability of fewer than 9 months with an odds ratio of 4.8 (95% confidence interval: 1.02–22.47). Conclusion Stepping-down treatment in well-controlled pediatric asthma resulted in a high failure rate. The author suggests initiating stepping-down treatment in patients whose duration of asthma stability is greater than 9 months may improve the rate of success.