Background: Adequate vitamin D status in mothers during pregnancy may influence the health status of the child later in life. We assessed whether maternal circulating 25-hydroxyvitamin D (25[OH]D) concentrations in pregnancy are associated with risk of lower respiratory tract infections, wheezing, and asthma in the offspring.
Methods: Data were obtained from 1724 children of the INfancia y Medio Ambiente (INMA) Project, a population-based birth cohort study. Maternal circulating 25(OH)D concentrations were measured in pregnancy (mean gestational age = 12.6 [SD = 2.5] weeks). When the child was age 1 year, parents were asked if their child had a physician-confirmed history of lower respiratory tract infections or a history of wheezing. The questions about wheezing were repeated annually thereafter. Asthma was defined as parental report of doctor diagnosis of asthma or receiving treatment at the age of 4–6 years or wheezing since the age of 4 years.
Results: The median maternal circulating 25(OH)D concentration in pregnancy was 29.5 ng/mL (interquartile range, 22.5–37.1 ng/mL). After multivariable adjustment, there was a trend for an independent association between higher levels of maternal circulating 25(OH)D levels in pregnancy and decreased odds of lower respiratory tract infections in offspring (for cohort- and season-specific quartile Q4 vs. Q1, odds ratio = 0.67 [95% confidence interval = 0.50–0.90]; test for trend, P = 0.016). We found no association between 25(OH)D levels in pregnancy and risk of wheezing at age 1 year or 4 years, or asthma at age 4–6 years.
Conclusions: Higher maternal circulating 25(OH)D concentrations in pregnancy were independently associated with lower risk of lower respiratory tract infections in offspring in the first year of life but not with wheezing or asthma in childhood.
From the aCenter for Research in Environmental Epidemiology (CREAL), Barcelona, Catalonia, Spain; bHospital del Mar Research Institute (IMIM), Barcelona, Catalonia, Spain; cCIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Catalonia, Spain; dNational Institute of Public Health, Cuernavaca, Mexico; eCenter for Public Health Research (CSISP), Valencia, Spain; fUniversity of Valencia, Valencia, Spain; gRey Juan Carlos University, Madrid, Spain; hDepartmento de Salud Pública, Hospital San Agustín, Servicio de Salud del Principado de Asturias (SESPA), Avilés, Asturias, Spain; iOviedo University, Asturias, Spain; jHospital San Agustin, Servicio de Salud del Principado de Asturias (SESPA), Avilés, Asturias, Spain; kServicio de Pediatría, Hospital Universitario Donostia, Servicio Vasco de Salud, Osakidetza, Euskadi, Spain; lDepartamento de Pediatría, Facultad de Medicina y Odontología, Universidad del País Vasco (UPV/EHU), Euskadi, Spain; mArea de Salud de Menorca, IB-SALUT, Menorca, Spain; nClinical Chemistry Unity, Public Health Laboratory of Bilbao, Euskadi, Spain; and oSubdirección de Salud Pública de Gipuzkoa, Departamento de Sanidad del Gobierno Vasco, Euskadi, Spain.
Submitted 4 February, 2011; accepted 6 September 2011; posted 14 November 2011.
This study was funded by grants from Instituto de Salud Carlos III and Spanish Ministry of Health (Red INMA G03/176; CB06/02/0041; FIS 97/0588; 00/0021-2, PI061756; PS0901958; FIS-FEDER 03/1615, 04/1509, 04/1112, 04/1931, 05/1079, 05/1052, 06/1213, 07/0314, and 09/02647; FIS-PI041436, FIS-PI081151, FIS-PI06/0867, and FIS-PS09/00090), Conselleria de Sanitat Generalitat Valenciana, Generalitat de Catalunya-CIRIT 1999SGR 00241, Department of Health of the Basque Government (2005111093 and 2009111069), the Provincial Government of Gipuzkoa (DFG06/004 and DFG08/001), and Fundación Roger Torné. The authors reported no other financial interests related to this research.
The above-mentioned funding agencies were not responsible for the design and conduct of the study, for the collection, management, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
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Correspondence: Eva Morales, Centre for Research in Environmental Epidemiology (CREAL), Parc de Recerca Biomèdica de Barcelona, Dr. Aiguader 88, 08003-Barcelona, Catalonia, Spain. E-mail: email@example.com.