Cutoff point estimation for serum vitamin D concentrations to predict cardiometabolic risk in Brazilian children

The effect of vitamin D supplementation on attacks in PFAPA syndrome patients with low vitamin D levels

BACKGROUND-AIM

To evaluate the effect of vitamin D supplementation on the frequency and duration of attacks in patients of PFAPA syndrome with low vitamin D levels.

METHODS

This retrospective study comprised PFAPA patients with vitamin D deficiency/insufficiency between 2018 and 2023. The frequency and duration of PFAPA attacks before and after vitamin D supplementation were noted.

RESULTS

Seventy-one patients were included. Of the 71 patients, 24 (33.8%) had vitamin D insufficiency, and 47 (66.2%) had vitamin D deficiency. In patients with vitamin D insufficiency, mean attack frequency and mean attack duration before vitamin D supplementation were 4.3 ± 1.9/year and 2.2 ± 1.6 days, respectively, while mean attack frequency and mean attack duration after vitamin D supplementation were 3.5 ± 2.7/year per year and 1.3 ± 0.9 days respectively (p = 0.2, p = 0.2, respectively). In patients with vitamin D deficiency, mean attack frequency and mean attack duration before vitamin D supplementation were 7.4 ± 2.1/year and 2.2 ± 1.6 days, respectively, while mean attack frequency and mean attack duration after vitamin D supplementation were 3.3 ± 2.4/year and 1.3 ± 0.9 days respectively (p < 0.01, p = 0.04, respectively). When the vitamin D level and the frequency of attacks were compared, the cut-off value of vitamin D was found to be 29.7 nmol/L.

CONCLUSIONS

In PFAPA patients with low vitamin D levels, the frequency and duration of PFAPA attacks were reduced with vitamin D supplementation. Especially at vitamin D level cut-off > 29.7 nmol/L, the frequency of attacks reduced significantly.

Breastfeeding and vitamin D

The recent re-emergence of vitamin D deficiency (VDD) and rickets among breastfed infants without adequate sunlight exposure and vitamin D supplementation has been reported worldwide. Breastfed infants are particularly vulnerable to VDD because of the low vitamin D content of breast milk, restricted sunlight exposure, increased pollution, and limited natural dietary sources of vitamin D. The prevalence of VDD in breastfed infants differs vastly between studies and nations at 0.6%-91.1%. The recommended intake of vitamin D for lactating mothers to optimize their overall vitamin D status and, consequently, of their breast milk is 200-2,000 IU/day, indicating a lack of consensus. Some studies have suggested that maternal high-dose vitamin D supplementation (up to 6,400 IU/day) can be used as an alternate strategy to direct infant supplementation. However, concern persists about the safety of maternal high-dose vitamin D supplementation. Direct infant supplementation is the currently available option to support vitamin D status in breastfed infants. The recommended dose for vitamin D supplementation in breastfed infants according to various societies and organizations worldwide is 200-1,200 IU/day. Most international guidelines recommend that exclusively or partially breastfed infants be supplemented with 400 IU/day of vitamin D during their first year of life. However, domestic studies on the status and guidelines for vitamin D in breastfed infants are insufficient. This review summarizes the prevalence of VDD in breastfed infants, vitamin D content of breast milk, and current guidelines for vitamin D supplementation of lactating mothers and infants to prevent VDD in breastfed infants.

Deficiency and Insufficiency of Vitamin D in Women of Childbearing Age: A Systematic Review and Meta-analysis

OBJECTIVE

 To estimate the prevalence of inadequate vitamin D level and its associated factors for women of childbearing age in Brazil.

METHODS

 A systematic review was conducted (last updated May 2020). Meta-analyses were performed using the inverse-variance for fixed models with summary proportion calculation by Freeman-Tukey double arcsine. Reporting and methodological quality were assessed using the Joanna Briggs Institute tool for prevalence studies.

RESULTS

 Our review identified 31 studies, comprising 4,006 participants. All the studies had at least one weakness, mainly due to the use of convenience sampling and small sample size. The overall prevalence of vitamin D deficiency, insufficiency, and both deficiency and insufficiency were 35% (confidence interval, 95%CI: 34-37%), 42% (95%CI: 41-44%), and 72% (95%CI: 71-74%), respectively.

CONCLUSION

 Although the magnitude of the prevalence of inadequate levels of vitamin D is uncertain, the evidence suggests that presence of vitamin D deficiency or insufficiency in women of reproductive age can cause moderate to severe problems.

Vitamin D is not associated with body composition and metabolic profile among Brazilian children with 25-hydroxyvitamin D ≥ 75 nmol/L: A cross-sectional study

BACKGROUND AND AIMS

The association of vitamin D with cardiovascular disease risk factors among children remains inconclusive, and there is a lack of studies that evaluate children with optimal serum 25-hydroxyvitamin D [25(OH)D]. Thus, this study aimed to analyze the relationship between serum 25(OH)D and body composition and metabolic profile among Brazilian children with sufficient serum 25(OH)D.

METHODS AND RESULTS

A cross-sectional study was conducted with 88 Brazilian children aged 4-11 years. Self-reported race, physical activity, anthropometry (body mass and height), body composition (waist circumference, body fat percentage, fat free mass, triceps and subscapular skinfolds), biochemical profile [lipid fractions, fasting glucose and 25(OH)D] and blood pressure data were collected. No difference was found in sex, self-reported race, physical activity, age, anthropometry, body composition, biochemical parameters and blood pressure between children with 25(OH)D 75-99 and ≥ 100 nmol/L. In addition, there was no association between serum vitamin D and body composition and metabolic profile.

CONCLUSIONS

Serum 25(OH)D was not associated with body composition and metabolic profile among Brazilian children with sufficient serum 25(OH)D. Further studies among children with serum levels ≥ 75 nmol/L are needed to confirm this finding.