Is high prevalence of vitamin D deficiency a correlate for attention deficit hyperactivity disorder?

Abstract

The aim of the study was to determine the association between vitamin D and attention deficit hyperactivity disorder (ADHD), and difference in the level of vitamin D in ADHD children and control. This a case-control study carried out in school health and primary health care clinics. A total of 1,331 children and adolescents who were diagnosed with ADHD based on clinical criteria and standardized questionnaires were enrolled in this study and were matched with 1,331 controls, aged 5-18years old. Data on body mass index (BMI), clinical biochemistry variables including serum 25-hydroxyvitamin D were collected. The study found significant association between ADHD and vitamin D deficiency after adjusting for BMI and sex (adj. OR 1.54; 95% CI 1.32-1.81; P<0.001). Majority of the ADHD children were in the age group 5-10years (40.7%), followed by 11-13years (38.4%). The proportion of BMI <85th percentile was significantly over represented in ADHD group as compared to healthy control (87.8 vs. 83%; P<0.001, respectively), while on the other hand, BMI >95th percentile was over represented in the control than ADHD group (7.6 vs. 4.6%; P<0.001, respectively). Mean values of vitamin D (ng/mL) were significantly lower in ADHD children (16.6±7.8) than in healthy children (23.5±9.0) (P<0.001). There was significant correlation between vitamin D deficiency and age (r=-0.191, P=0.001); calcium (r=0.272, P=0.001); phosphorous (r=0.284, P=0.001); magnesium (r=0.292, P=0.001); and BMI (r=0.498, P=0.001) in ADHD children. The vitamin D deficiency was higher in ADHD children compared to healthy children.