“Vitamin D in Pregnancy and Attention Deficit Hyperactivity Disorder Symptoms in Childhood”
30/05/2016
Attention deficit and hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders of childhood, characterized by persistent inattention and/or hyperactivity–impulsivity resulting in substantial functional impairment. In 2011, the CDC (Centers for Disease Control and Prevention) estimated that approximately 11{3effe4377b6f02be2524d084f7d03914ac32a2b62c0a056ca3444e58c1f10d0b} of the US children 4–17 years of age (6.4 million) were diagnosed with ADHD with increasing rates in the last decade. Although the causes of ADHD remain unknown, genetic factors are probably the most important determinants of the development of these disorders but life-style and environmental factors acting in pregnancy have been proposed as potential triggers of ADHD symptoms. Vitamin D, which takes part in important processes of brain development, has antioxidant and anti-inflammatory properties which could be important for protecting the developing brain against harmful environmental triggers. Also, it has been hypothesized that diverse insults that increase oxidative stress, such as infections, toxins, fever, and inflammation, could influence the risk of autism spectrum disorder in vitamin D-deficient pregnant women and young children, which could also be translated to ADHD disorder.
This study examines the association between maternal vitamin D levels during pregnancy and ADHD-like symptoms in childhood. About 1650 mother-child INMA project pairs (from five study areas: Menorca, Valencia, Sabadell, Asturias and Gipuzkoa) were included in this study, which showed that higher concentrations of vitamin D during pregnancy were associated with a decreased risk of ADHD symptoms in offspring at ages 4–5 years. In addition, this relationship was also observed among children classified as having ADHD diagnostic criteria. This decrease of ADHD symptoms was stronger for high concentrations of vitamin D measured during the first trimester of pregnancy compare to exposure during the second and third trimester. The results didn’t change when they took into account smoke during pregnancy, preterm deliveries and low birth weight newborns.
Given the high prevalence of vitamin D deficiency among childbearing women, these findings could have important public health implications. Further studies are necessary to increase the understanding of the mechanisms linking maternal vitamin D and a reduced risk of ADHD in childhood, and also to analyze if vitamin D supplementation can reduce risk of ADHD in offspring later in life. Meanwhile, pregnant women should follow all diet supplements recommendations given by their doctors.
Reference: Morales E, Julvez J, Torrent M, Ballester F, Rodríguez-Bernal CL, Andiarena A, Vegas O, Castilla AM, Rodriguez-Dehli C, Tardón A, Sunyer J. Vitamin D in Pregnancy and Attention Deficit Hyperactivity Disorder-like Symptoms in Childhood. Epidemiology. 2015 Jul;26(4):458-65.