Maternal race, vitamin D intake impact offspring allergy, asthma
Prenatal vitamin D status and a mother’s race affected their children’s allergy and some pulmonology outcomes, according to two studies presented at the annual meeting of the American Academy of Allergy, Asthma & Immunology in Orlando.
Researchers in the first study looked at the link between prenatal vitamin D levels and allergic rhinitis in children of 1,091 women-child dyads participating in the Conditions Affecting Neurocognitive Development in Early Childhood (CANDLE) cohort in Tennessee. Maternal vitamin status was ascertained in the second trimester and the children’s allergic rhinitis status was determined while they were between 4 and 6 years of age. Results were analyzed utilizing covariates such as the season of the child’s birth, sex, education and whether the mother had asthma.
Sixty-seven percent of the women studied were black and 23% of the children had allergic rhinitis. The median vitamin D levels were 25.1 ng/mL in the white women and 19.2 ng/mL in the black women.
“Since allergic rhinitis is influenced by hereditary and environmental factors and often begins early in life, it is important to understand prenatal factors associated with increased risk or that may help prevent the condition,” Christina Ortiz, MD, MPH, an allergy andimmunology fellow at Vanderbilt University Medical Center, told Healio Family Medicine.
“Vitamin D plays a role in development of the immune system and low levels can be treated, so it is considered a potentially modifiable factor associated with allergic rhinitis.”
Researchers found an interquartile range increase (15-27 ng/mL) in maternal vitamin D was linked to an increased possibility of child allergic rhinitis in black women (aOR = 1.4; 95% CI: 1.04-1.88). Conversely, this increase was not significantly linked to child allergic rhinitis (aOR = 0.79; 95% CI, 0.52-1.2) in white women.
“Previous observational studies have found potential racial differences in the association of vitamin D and asthma and atopic condition such as allergic rhinitis, but it was surprising to see such a striking difference by race,” Ortiz said in the interview. “However, we don’t advocate for any changes in recommendations as we further investigate the reason for our findings.”
Future studies on the same topic that include more black women with higher vitamin D levels would be helpful, she added.
In the second study, researchers examined the link between prenatal plasma concentrations of vitamin D and childhood asthma of 964 women and their children enrolled in same cohort in Tennessee.
“Vitamin D deficiency is common,” Sarah Adams, MD, allergy and immunology fellow at the Vanderbilt University Medical Center, told Healio Family Medicine. “Understanding the relationship between prenatal vitamin D and the development of asthma in children is important in efforts to lessen the burden of one of the most chronic conditions in childhood, and understanding vitamin D’s relationship to asthma and wheeze is an important public health effort.”
Of the group Adams and colleagues studied, 65% were black and 12% had asthma. Researchers also used covariates such as the season of the child’s birth, sex, education and whether the mother had asthma.
Adams and colleagues found median vitamin D levels were 25 ng/mL in the mothers who were white and 19.35 ng/mL in the mothers who were black. In addition, a multivariable analysis showed an interquartile range increase (15-27 ng/mL) was linked to a protective trend in white women (aOR = 0.62; 95% CI, 0.35-1.1) and the opposite in black women (aOR = 1.33; 95% CI, 0.93-1.9).
“A secondary analysis of a recent randomized clinical trial did not find that the association of prenatal vitamin D and child wheeze/asthma was modified by maternal race. As a result, our results in this context were a bit surprising,” Adams said in the interview. “Overall the black women in the cohort had vitamin D levels that were lower than white participants and few black women had high levels so there was limited variability in the range of levels. However, the reason for our findings are still unclear. This deserves further research.”
She added she also intends to look into mechanisms that could explain the differences detected, as well as follow-up with the children as they grow up to evaluate their asthma and lung functions again. – by Janel Miller
Carroll KN, et al. “Association between maternal prenatal vitamin D concentration and child asthma.” Presented at: American Academy of Allergy, Asthma and Immunology annual meeting; March 2-5, 2018; Orlando.
Ortiz CF, et al. “Association between prenatal vitamin D and child allergic rhinitis.” Presented at: American Academy of Allergy, Asthma and Immunology annual meeting; March 2-5, 2018; Orlando.
Disclosure: Neither Adams nor Ortiz report any relevant financial disclosures. Healio Family Medicine was unable to determine the other authors’ relevant financial disclosures prior to publication.