In a recent study published in the journal Nutrients, Researchers in Australia investigated the possible link between vitamin D levels in newborns and the development of longitudinal eczema by age 25. They found that higher levels of vitamin D in newborns were associated with reduced odds of persistent early-onset eczema and increased risk of early-onset eczema.
Study: Neonatal vitamin D and associations with longitudinal changes in eczema up to 25 years. Image credit: marishkaSm / Shutterstock
Record
Atopic dermatitis, or eczema, is a common inflammatory skin condition that can result from immune disruption and skin barrier dysfunction, and its underlying pathophysiology remains unclear. Evidence suggests that vitamin D levels in early life may play a role in the development of eczema. Vitamin D deficiency and the prevalence of eczema are higher in areas with less sunlight. Vitamin D receptors on immune cells suggest its involvement in the regulation of immune responses. Evidence from cohort studies suggests a link between higher levels of vitamin D in cord blood and a reduced risk of eczema in early childhood. However, clinical trials in women with vitamin D supplementation during pregnancy have produced inconsistent results. Current guidelines do not universally recommend such supplementation due to limited data on its effects on allergic diseases in the offspring.
Despite the recognition of different eczema phenotypes, no studies have investigated the association between the development or phenotypes of longitudinal eczema and neonatal vitamin D or 25(OH)D3, its most stable circulating form. Therefore, the investigators in the present study aimed to investigate how neonatal serum 25(OH)D3 levels relate to the prevalence of eczema at various ages between 1 and 25 years and the eczema phenotype up to age 25 years.
About the study
The Melbourne Atopy Cohort Study (MACS) followed 223 infants with a family history of allergic disease, including self-reported asthma, allergic rhinitis, eczema or severe food allergy, from birth to age 25. Infants had parents of Australian descent and high socioeconomic status. Data collection included telephone surveys, clinical examinations and skin tests (SPT) at 6 months and 1, 2, 12, 18 and 25 years. At age 18, participants consented to access newborn screening cards for measurement of neonatal 25(OH)D3 levels via dry blood spot (DBS).
Widespread eczema was defined based on parental or self-reported diagnosis of eczema or rash treated with topical steroids. Longitudinal eczema phenotypes were identified using latent class analysis, resulting in the following subcategories: early-onset resolving eczema, early-onset persistent eczema, mid-onset eczema, mid-onset persistent eczema, and minimal/no eczema. Eczema/sensitization phenotypes were determined based on eczema and allergen sensitization (cow’s milk, egg white, peanut, house dust mite, cat dander, and ragweed), with participants categorized into atopic eczema, non-atopic eczema, asymptomatic-sensitized , or groups at each age.
Statistical analysis included the use of logistic regression models, odds ratios, generalized estimating equations (GEE), likelihood ratio tests, Wald tests, directed acyclic graphs, and sensitivity analysis.
Results and discussion
The maximum prevalence of eczema was found to be in infancy (31.2%), decreasing to 15.9% at age 6 and increasing to 26% at age 25. found to be 32.5 nmol/L. As expected, a significant association was observed between vitamin D levels and birth season (p < 0.001), indicating that children born in winter had lower 25(OH)D3 levels. In sensitivity analysis, adjusting for season of birth, higher levels of neonatal vitamin D were associated with a reduced risk of eczema at 1–2 years. Maternal smoking during pregnancy was found to modify the association. In addition, higher neonatal vitamin D levels were found to be associated with a reduced risk of eczema at age 2 years in participants with a maternal history of smoking, compared to those without.
Neonatal vitamin D (25(OH)D3) level in 223 MACS participants. The median level was 32.5 nmol/L. P25 was 21.6 nmol/L, P75 was 44.7 nmol/L, and the mean was 35.9 ± 18.6 nmol/L.
Higher levels of neonatal vitamin D were found to be associated with a reduced risk of early-onset persistent eczema (aMOR = 0.74), as well as an increased risk of early-resolving eczema (aMOR = 1.30) compared with minimal/no eczema subcategory until the age of 12. Similar trends persisted for eczema phenotypes for up to 25 years. Maternal birthplace influenced the association – increased neonatal vitamin D levels were associated with reduced odds of early-onset persistent eczema up to 12 years of age in children of non-Australian/New Zealand-born mothers, but not in those of Australian-born mothers /New Zealand . Paternal education and maternal prenatal smoking were also found to modify the association with eczema phenotypes up to 25 years.
The study is strengthened by its control for various confounders and prospective design. However, the study is limited by small sample size, attrition over time, potential for reduced precision in estimates, and low generalizability beyond high allergy risk cohorts.
conclusion
In conclusion, the study shows that increased vitamin D levels in newborns could potentially reduce the likelihood of early-onset persistent eczema, subject to possible modifications by maternal smoking during pregnancy and place of birth. Further observational studies in different populations are needed to validate these findings. In addition, well-designed clinical trials are warranted to investigate the efficacy of maternal vitamin D supplementation in the prevention of eczema, particularly persistent early-onset cases.
