How Does Vitamin D Relate to Tics and ADHD in Children?

What you need to know

• Contrary to previous research, this large study did not find a link between low vitamin D levels and tic severity in children with chronic tic disorders.
• However, lower vitamin D levels were associated with higher rates of ADHD and more severe ADHD symptoms in children with tic disorders.
• The study suggests vitamin D levels may be a useful marker for ADHD symptoms in children with tic disorders, but more research is needed.

Background on tic disorders and vitamin D

Chronic tic disorders, including Tourette syndrome, are conditions that cause children to make repeated, sudden movements or sounds called tics. These disorders affect about 1% of children and often occur along with other conditions like obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD).

Vitamin D is an important nutrient that helps our bodies absorb calcium for strong bones. It also plays roles in brain development, immune function, and regulating mood. Our bodies can make vitamin D when our skin is exposed to sunlight, and we can get it from certain foods or supplements.

Some previous small studies had suggested that children with tic disorders tend to have lower vitamin D levels, and that vitamin D supplements might help reduce tics. However, the evidence was limited. This large study aimed to take a closer look at the potential connections between vitamin D levels, tics, and related conditions in children.

About the study

This study was part of a larger European project called EMTICS that followed children with and without tic disorders over time. For this analysis, the researchers measured vitamin D levels in blood samples from:

• 327 children with chronic tic disorders
• 31 children who developed tics during the study
• 93 children without tics who had a parent or sibling with a tic disorder

The children were from multiple countries across Europe and Israel. The researchers looked at whether vitamin D levels were associated with:

• Having a tic disorder
• Tic severity
• Having OCD or ADHD along with tics
• OCD and ADHD symptom severity

Key findings

Vitamin D and tics

Contrary to what the researchers expected based on previous studies:

• Children with tic disorders did not have lower vitamin D levels compared to the unaffected children.
• There was no link between vitamin D levels and tic severity.
• Children who developed tics during the study did not have significantly different vitamin D levels compared to those who remained tic-free.

So this larger, more comprehensive study did not support the idea that low vitamin D contributes to tics or makes tics worse.

Vitamin D and ADHD

The most intriguing findings related to ADHD:

• Among children with tic disorders, those with lower vitamin D levels were more likely to also have ADHD.
• Lower vitamin D was associated with more severe ADHD symptoms, especially inattention.
• For every 10 ng/mL increase in vitamin D levels, the odds of having ADHD decreased by about 45%.

These results suggest there may be an important relationship between vitamin D and ADHD symptoms in children with tic disorders. However, this study cannot prove that low vitamin D actually causes ADHD symptoms.

Vitamin D and OCD

The findings for OCD were less clear:

• Among children with tics, higher vitamin D levels were actually associated with slightly higher odds of having OCD.
• However, vitamin D levels were not related to OCD symptom severity.

The researchers aren’t sure how to explain this unexpected result. It’s possible that children diagnosed with both tics and OCD receive more medical attention and are more likely to take vitamin supplements.

What this means for families and doctors

This study suggests that low vitamin D likely does not play a major role in causing or worsening tics in most children. So taking vitamin D supplements probably won’t help reduce tics for children who aren’t deficient.

However, the link between low vitamin D and ADHD symptoms is intriguing. ADHD is very common in children with tic disorders and can significantly impact quality of life. The researchers suggest vitamin D levels could potentially be a useful marker to help monitor ADHD symptoms in children with tics.

It’s important to note that this study doesn’t prove that low vitamin D causes ADHD symptoms or that supplements would necessarily help. There could be other explanations for the association. For example, children with more severe ADHD may spend less time outside in the sun or have poorer diets, leading to lower vitamin D.

More research is still needed, but these findings open up some interesting possibilities:

• Doctors may want to consider checking vitamin D levels in children with tics and ADHD symptoms.
• For children found to be vitamin D deficient, supplementation could potentially help with ADHD symptoms, though this needs to be studied further.
• Spending more time outdoors in the sun might have multiple benefits for children with tics and ADHD - increasing vitamin D naturally while providing opportunities for physical activity.

Limitations to keep in mind

While this was a large, well-designed study, it does have some limitations:

• It only looked at vitamin D levels at one point in time, so it can’t show cause-and-effect relationships.
• The study didn’t have a comparison group of completely unaffected children without a family history of tics.
• Information on diet, sun exposure, supplement use, and other factors that affect vitamin D levels wasn’t available.

Conclusions

• Low vitamin D doesn’t appear to be a major contributor to tics in most children, contrary to what some previous smaller studies suggested.
• There may be an important relationship between vitamin D and ADHD symptoms in children with tic disorders that warrants further research.
• Vitamin D levels could potentially be a useful marker to monitor in children with both tics and ADHD.
• More studies are needed to determine if vitamin D supplementation could help reduce ADHD symptoms in children with tic disorders who are deficient.

Overall, this study highlights the complex relationships between vitamin D and brain health in children. While many questions remain, the findings provide new directions for research that may eventually lead to improved care for children with tic disorders and ADHD.