Prospective study of disease persistence and lung function trajectories of childhood asthma

Long-term effects of vitamin D on exacerbation rate, health care utilization and lung function in children with asthma

BACKGROUND

Asthma exacerbations lead to unplanned health care utilization and reduced lung function in children. Sufficient vitamin D level has been found to have a short-term protective effect against asthma exacerbation in children. However, it is unclear whether this effect remains in the long term. We evaluated the long-term effects of vitamin D levels on the occurrence of asthma exacerbations, emergency department visits or hospitalizations, and lung function among children with asthma, and further investigated the temporal trends of the effects.

METHODS

In this retrospective cohort study, children with asthma who were admitted to the Children's Hospital of Chongqing Medical University from 2017 to 2021 were enrolled. Negative binomial, Poisson, or logistic regression model was used for the multivariable analysis, adjusting for age, sex, body mass index z-score, and severity of asthma exacerbation.

RESULTS

Of the 370 children with asthma, 87.8% had vitamin D level less than or equal to 30 ng/mL. After adjustment for confounding factors, higher baseline vitamin D levels in asthma children were significantly associated with reduced occurrence of asthma exacerbations during the first [odds ratio 0.842, 95% confidence interval (CI): 0.805-0.881; P<0.001], second (odds ratio 0.848, 95% CI: 0.793-0.907; P<0.001) and third years (odds ratio 0.865, 95% CI: 0.811-0.922; P<0.001) of follow-up. Higher vitamin D levels in asthmatic children were also strongly associated with a reduced number of emergency department visits or hospitalizations during the first (odds ratio 0.880, 95% CI: 0.842-0.920; P<0.001), second (odds ratio 0.885, 95% CI: 0.832-0.941; P<0.001), and third years (odds ratio 0.922, 95% CI: 0.851-0.998; P=0.044) of follow-up. In addition, the vitamin D levels in asthmatic children were found to be negatively associated with the odds of large airway dysfunction (odds ratio 0.865, 95% CI: 0.771-0.970; P=0.013) and small airway dysfunction (odds ratio 0.922, 95% CI: 0.855-0.996; P=0.038) during the first year of follow-up.

CONCLUSIONS

Sufficient vitamin D level is associated with lower risk of asthma exacerbations and health care utilization over a 3-year period, and improved lung function over 1 year. The protective effects of vitamin D on asthmatic children decreased over time.

A longitudinal study of risk factors associated with white spot disease occurrence in marine shrimp farming in Rayong, Thailand

Background

A longitudinal study was conducted to analyze farm characteristics, farm practices, and biosecurity measures that influenced the occurrence of white spot disease (WSD) in shrimp farming in Rayong, Thailand.

Methods

Data were collected using a structured interview schedule administered between October 2017 and September 2019. A generalized estimating equations (GEE) model was used to identify risk factors. From the 270 responses, 86 possible risk factors were analyzed using univariate and multivariate analysis.

Results

We found that 17 possible risk factors were statistically significant with an alpha level of 1% and associated with WSD status. In the final model, multivariate analysis found that two independent variables were statistically significant. First, the absence of inclement weather during ponding was a statistically significant factor associated with WSD occurrence and it prevented WSD occurrence as the odds ratio (OR) was <1 (OR = 0.196, P = 1.3 × 10^-5). Second, the separation of ponds into three specific types (cultured, water treatment, and pond for water reservoir) was significantly associated with WSD occurrence. Likewise, the presence of this ponding system was a protective factor against WSD (OR = 0.0828, P = 0.001).

Conclusions

The results of this study offer a reference for farmers and relevant authorities when addressing WSD occurrence in shrimp farming. In addition, our results can help relevant authorities in controlling WSD in other endemic areas.