Tourette syndrome and chronic tic disorder patients were twice as likely to be diagnosed with metabolic and cardiovascular disorders, a longitudinal study of Swedish health registries found.
Compared with the general population, people diagnosed with Tourette syndrome or chronic tic disorder had a higher risk of being diagnosed with:
- Any metabolic or cardiovascular disorder: adjusted HR 1.99 (95% CI 1.90-2.09)
- Obesity: adjusted HR 2.76 (95% CI 2.47-3.09)
- Type 2 diabetes: adjusted HR 1.67 (95% CI 1.42-1.96)
- Circulatory system diseases, including hypertension and cardiovascular problems: adjusted HR 1.76 (95% CI 1.67-1.86)
Risks of any metabolic or cardiovascular disorder were evident from childhood and were significantly reduced when individuals with comorbid attention-deficit-hyperactivity disorder (ADHD) were excluded (adjusted HR 1.52, 95% CI 1.42-1.62), reported Lorena Fernandez de la Cruz, PhD, of the Karolinska Institutet in Stockholm, and colleagues.
In addition, risks of metabolic and cardiovascular disorders were lower with longer exposure to antipsychotic medication, the researchers wrote in JAMA Neurology.
“Until recently, we knew very little about the physical health of individuals with Tourette syndrome and chronic tic disorders, particularly in the long run,” Fernandez de la Cruz told MedPage Today. “The Swedish registers, which have full coverage of the population’s medical health records for over 40 years, offered a unique opportunity to examine the long-term health status of these patients.”
But drawing conclusions from this data may be problematic, said Donald Gilbert, MD, director of the Tourette Syndrome Clinic at Cincinnati Children’s Hospital Medical Center.
“There is ample reason for skepticism in using this paper to inform either clinical practice or public policy,” Gilbert, who was not part of the study, told MedPage Today.
Because the researchers included only patients who were hospitalized or treated in outpatient specialty clinics, “complex patients with multiple diagnoses — for example, both tic disorders and obesity — are likely over-represented compared to the general population, and patients with obesity or heart disease alone may be under-represented,” he said. “This could make associations between two conditions — like Tourette and heart disease — appear more common than they are in the general population.”
And recognition of Tourette syndrome was increasing during the study period while the overall incidence of obesity also was increasing. “Tic disorders may have been more likely to be diagnosed in children and adults receiving extra healthcare visits for obesity or cardiovascular disease,” Gilbert added.
In the study, Fernandez de la Cruz and colleagues looked at registry records of 14,045,026 people living in Sweden from 1973 to 2013. Of that sample, 7,804 individuals (76.4% male; median age 13.3 at first diagnosis) had a registered diagnosis of Tourette syndrome or chronic tic disorder in specialist care.
The researchers also compared patients with Tourette’s or chronic tic disorder against siblings, controlling for possible shared familial confounders, and found they had a higher risk of any cardiometabolic disorder than unaffected brothers and sisters (adjusted HR of 1.37, 95% CI 1.24-1.51).
In an exploratory analysis of 6,324 people with Tourette’s or chronic tic disorder from the Swedish Prescribed Drug Register, using antipsychotic medication for up to 1 year was not linked with a significantly increased risk of metabolic and cardiovascular disorders (adjusted HR 0.83, 95% CI 0.56-1.24).
Using antipsychotics for more than 1 year was tied to a significantly decreased risk (adjusted HR 0.27; 95% CI 0.17-0.43), however. Patients taking medication may differ from patients not on medication and may have more frequent follow-ups, Fernandez de la Cruz’s group wrote: “Because this is an observational study, we are careful not to ascribe the reduction of the risk to the medication itself.”
Specialty clinic doctors also may have more rapidly discontinued antipsychotics in children who gained weight, Gilbert said.
Besides its observational nature, the study has other limitations, the researchers noted. It does not represent all Swedish patients with Tourette syndrome or chronic tic disorder; many people with mild tics do not seek help and patients diagnosed in primary care are not included in the registers.
It also does not include information about behavioral variables that might affect cardiometabolic health — sedentary lifestyle, unhealthy eating habits, or smoking, for example — or non-drug strategies to manage them, they added.
The study was supported by Tourettes Action and the Swedish Research Council for Health, Working Life and Welfare.
Fernandez de la Cru and co-authors disclosed relevant relationships with the Swedish Research Council, Shire, Tourettes Action, UpToDate, Wolters Kluwer Health, and Elsevier.