Children with lower respiratory tract infections and serum 25-hydroxyvitamin D3 levels: A case-control study

Vitamin D supplementation and lower respiratory tract infection in infants: a nested case-control study

PURPOSE

To assess the association between vitamin D (VD) supplementation and the risk of lower respiratory tract infection (LRTI) among infants.

METHODS

This is a nested case-control study from an ongoing prospective birth cohort in Wuhan from 2013. Cases were subjects free of neonatal pneumonia but later developed LRTI during infancy, who were matched with five randomly selected controls by infant sex, birth year, and birth season. We included 190 cases and 950 controls in the final analysis. The primary outcome was the first LRTI incident and the exposure was VD supplementation from birth to the index endpoint. The association between VD supplementation and LRTI risk was assessed using the Cox proportional-hazards regression model.

RESULTS

Infants taking supplements had a 59% relative reduction in the hazard ratio of LRTI (HR = 0.41; 95% CI 0.26, 0.64) compared to those not supplemented. There was a linear relationship between LRTI risk and VD supplementation within range of 0-603 IU/day: for each 100 IU per day increment in VD supplementation, infants experienced a 21% lower risk of developing LRTI (adjusted HR: 0.79; 95% CI 0.71, 0.89). The linear relationship was stably observed in the sensitivity analyses as well.

CONCLUSIONS

VD supplementation was associated with the reduced risk of LRTI throughout infancy, and the optimal supplementation dose for infants may be beyond the current recommendation.

Relationship between Acute Respiratory Tract Infection and the Serum 25(OH) D3 Level in Chronic Kidney Disease Patients and Its Prevention and Treatment

Observational studies and randomized controlled studies propose that vitamin D plays a significant role in preventing acute respiratory tract infection (RTI); however, results are inconsistent and the optimal serum 25-hydroxyvitamin D (25-OH-D3) concentration remains unknown. This study explores the risk factors associated with acute RTI in patients with chronic kidney disease (CKD) and analyzes its correlation with serum 25-OH-D3 levels, to provide appropriate preventive treatment measures for CKD patients complicated with acute RTI. Seventy cases of CKD patients treated in the department of nephrology of Jiangxi Provincial People’s Hospital are recruited as the research objects and divided into a control group (CKD without RTI) and an observation group (CKD with RTI), with 35 cases in each group. The laboratory indexes and serum 25-OH-D3 levels are compared between the two groups. The area under the receiver operating characteristic curve (ROC) of 25-OH-D3 in the diagnosis of CKD patients complicated with RTI is 0.892, and the standard error is 0.038. The glomerular filtration rates (GFR) are $48.32\pm 9.87\text{mL}/\min$ and $50.18\pm 20.71\text{mL}/\min$ in the control group and the experimental group, respectively, with no statistical significance between the two groups ( $P>0.05$ ). The serum 25-OH-D3 content in the control group ( $35.08\pm 6.2\text{nmol}/\text{L}$ ) is dramatically higher than that in the observation group ( $20.71\pm 5.87\text{nmol}/\text{L}$ ) ( $P<0.05$ ). The proportion of patients with diabetes mellitus (DM) in the control group and observation group is 25.71% and 68.57%, respectively, with a considerable difference ( $P<0.05$ ). In the control group and the experimental group, the proportion of patients with oral vitamin D receptor agonists is 54.29% and 11.43%, respectively, and the difference is significant ( $P<0.05$ ). Results show that the serum 25-OH-D3 level is highly correlated with the occurrence of RTI in CKD patients. In addition, it is related to patients’ age, DM, and vitamin D receptor agonists.

Vitamin D deficiency and severity of pneumonia in Indonesian children

Objective

To determine the prevalence of vitamin D deficiency in Indonesian children hospitalized with pneumonia and evaluate the association between vitamin D status and severity of pneumonia.

Methods

A hospital-based cross-sectional study was conducted from February 2016 to July 2017 in two district hospitals in Yogyakarta province, Indonesia. Infants and young children aged 2–59 months hospitalized with pneumonia were recruited. Serum blood samples were collected on admission and analyzed for total serum 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 concentrations using liquid chromatography-tandem mass spectrometry. Vitamin D deficiency was defined as a level of serum vitamin D <50 nmol/L. The association between vitamin D deficiency and severity of hospitalized pneumonia according to WHO criteria, including the presence of danger signs, hypoxemia (SpO2 in air below 90%), duration of hospitalization, and admission to Intensive Care Unit (ICU), was analyzed using logistic regression.

Results

133 children with WHO-defined pneumonia were enrolled in the study and 127 (96%) had their vitamin D status determined. The mean vitamin D concentration was 67 (± 24 SD) nmol/L and 19% of participants were vitamin D deficient. Age younger than 6 months was associated with prolonged hospitalization (> 5 days) and low birth weight and poor nutritional status on admission were risk factors for hypoxemia. However, vitamin D status was not associated with the presence of danger signs, duration of hospitalization, or hypoxemia.

Conclusions

One in every five children hospitalized with pneumonia was vitamin D deficient. Vitamin D status was not associated with the severity of pneumonia.

Is vitamin D deficiency a public health concern for low middle income countries? A systematic literature review

PURPOSE

Vitamin D deficiency has been receiving increasing attention as a potential public health concern in low and lower-middle income countries (LMICs), of which there are currently 83. We aimed to conduct a comprehensive systematic literature review (SLR) of available data on vitamin D status and prevalence of vitamin D deficiency in all 83 LMICs.

METHODS

We followed the general methodology for SLRs in the area of serum 25-hydroxyvitamin D. Highest priority was placed on identifying relevant population-based studies, followed by cross-sectional studies, and to a lesser extent case-control studies. We adopted the public health convention that a prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D < 25/30 nmol/L) at > 20% in the entire population and/or at-risk population subgroups (infants, children, women of child-bearing age, pregnancy) constitutes a public health issue that may warrant intervention.

RESULTS

Our SLR revealed that of the 83 LMICs, 65% (n = 54 countries) had no published studies with vitamin D data suitable for inclusion. Using data from the remaining third, a number of LMICs had evidence of excess burden of vitamin D deficiency in one or more population subgroup(s) using the above convention (Afghanistan, Pakistan, India, Tunisia and Mongolia) as well as possibly other LMICs, albeit with much more limited data. Several LMICs had no evidence of excess burden.

CONCLUSION

Vitamin D deficiency is a public health issue in some, but certainly not all, LMICs. There is a clear need for targeting public health strategies for prevention of vitamin D deficiency in those LMICs with excess burden.