Having pets, especially dogs, in the house during pregnancy may increase cord blood vitamin D.

Having a pet in the home, and associated increased outdoor activity, during the prenatal period was associated with higher cord blood vitamin D, according to research according to research out of Henry Ford Hospital & Health System in Detroit, MI. However, the association was seen only among whites.

Christine Cole Johnson, PhD, MPH, and colleagues analyzed data from a large, geographically based, general-risk birth cohort. Household pets were assessed during pregnancy; serum level of 25 (OH)D (25-hydroxyvitamin D) in cord blood was used as the measure of vitamin D and a marker of maternal level. Because of notable differences in vitamin D concentrations between African Americans and whites, analyses were stratified by race.

A total of 1055 newborns were included in the study (62.4% African American, 49.4% were female). For whites, but not African Americans,  having no pet, when compared with having one pet or or more than one pet during pregnancy was associated with lower cord blood vitamin D (37.7, 45.2, and 47.0 nmol/L, respectively, P=0.001). Considering type of pet, the relationship for no pet compared with one or more than one dog (37.7, 46.1, and 49.9 nmol/L, respectively, P=0.001) was similar to that for no pet versus one cat or more than one cat (37.7, 43.0, and 46.5 nmol/L, respectively, P=0.065).

According to Dr. Johnson and colleagues, “This racial difference may reflect an impact on pet owner behavior resulting in increased outdoor exposure that is limited to lighter skinned individuals.”