Interplay between serum vitamin D, irisin and galectin-3 in attention-deficit/hyperactivity disorder (ADHD)

Vitamin D deficiency (VDD) has been widely studied for its role in attention-deficit/hyperactivity disorder (ADHD). Irisin is believed to act as a bridge between physical activity and cognition, while galectin-3 is involved in inflammation and immunity. Serum irisin and Galectin-3 levels are altered with vitamin D levels.

A prospective case-control study was conducted to investigate the interplay between the serum levels of vitamin D, irisin and galectin-3 in South Indian children diagnosed with ADHD. We enrolled 152 children (n = 76 each in ADHD and healthy control) and evaluated their serum Vitamin D levels and estimated serum irisin and galectin-3 levels in a subpopulation of 70 children, among them (35 each in ADHD and matched controls).

VDD was more common in ADHD (n = 46; 60.5%) than in healthy controls (n = 22; 28.9%). Median serum vitamin D levels were significantly lower (16.99 (IQR 11.91-23.98) ng/mL) in ADHD than in controls (22.55 (IQR 18.92-28.81) ng/mL) (p < 0.001). Serum Irisin levels were lower, and galectin-3 levels were higher in ADHD than in healthy controls, although not statistically significant. Interestingly, there was a strong positive correlation between serum irisin and galectin-3 in ADHD (r = 0.707, p < 0.001), while the correlation was weak in controls (r = 0.336, p value 0.049).

The high prevalence of VDD in ADHD implies the importance of vitamin D and its proper monitoring. The strong positive correlation between irisin and galectin-3 in ADHD highlights the possibility of the irisin-galectin-3 duo serving as a potential biomarker in ADHD, subject to confirmation in a larger population.