Vitamin D levels in children and adolescents with chronic tic disorders: a multicentre study
Authors: Bond Molly , Moll Natalie , Rosello Alicia , Bond Rod , Schnell Jaana , Burger Bianka , Hoekstra Pieter J. , Dietrich Andrea , Schrag Anette , Kocovska Eva , Martino Davide , Mueller Norbert , Schwarz Markus , Meier Ute-Christiane ,   the EMTICS Collaborative Group, Bruun Julie E. , Grejsen Judy , Ommundsen Christine L. , Rubæk Mette , Enghardt Stephanie , Bokemeyer Stefanie , Driedger-Garbe Christiane , Reichert Cornelia , Schmalfeld Jenny , Duffield Thomas , Gergye Franciska , Kovacs Margit , Vidomusz Reka , Carmel Miri , Fennig Silvana , Gev Ella , Keller Nathan , Michaelovsky Elena , Nahon Matan , Regev Chen , Simcha Tomer , Smollan Gill , Weizman Avi , Gagliardi Giuseppe , Tallon Marco , Roazzi Paolo , van den Ban Els , de Bruijn Sebastian F. T. M. , Driessen Nicole , Lamerz Andreas , Messchendorp Marieke , Rath Judith J. G. , Sival Nadine Schalk Deborah , Tromp Noor , Visscher Frank , de la Tourettes Stichting Gilles , Cáceres Maria Teresa , Carrillo Fátima , Gómez-Garre Pilar , Vargas Laura , Gariup Maria , Stöber Sara , Apter Alan , Baglioni Valentina , Ball Juliane , Benaroya-Milshtein Noa , Bodmer Benjamin , Bond Molly , Bognar Emese , Burger Bianka , Buse Judith , Cardona Francesco , Vela Marta Correa , Dietrich Andrea , Debes Nanette M. , Ferro Maria Cristina , Fremer Carolin , Garcia-Delgar Blanca , Gulisano Mariangela , Hagen Annelieke , Hagstrøm Julie , Hedderly Tammy J. , Heyman Isobel , Hoekstra Pieter J. , Huyser Chaim , Madruga-Garrido Marcos , Marotta Anna , Martino Davide , Meier Ute-Christiane , Mir Pablo , Moll Natalie , Morer Astrid , Mueller Norbert , Müller-Vahl Kirsten , Münchau Alexander , Nagy Peter , Neri Valeria , Openneer Thaïra J. C. , Pellico Alessandra , Vasco Ángela Periañez , Plessen Kerstin J. , Porcelli Cesare , Redondo Marina , Rizzo Renata , Roessner Veit , Ruhrman Daphna , Schnell Jaana M. L. , Schrag Anette , Schwarz Marcus J. , Silvestri Paola Rosaria , Skov Liselotte , Steinberg Tamar , Gloor Friederike Tagwerker , Tarnok Zsanett , Tübing Jennifer , Turner Victoria L. , Walitza Susanne , Weidinger Elif , Woods Martin L. 
Published: April 2021

This study investigated whether vitamin D is associated with the presence or severity of chronic tic disorders and their psychiatric comorbidities. This cross-sectional study compared serum 25-hydroxyvitamin D [25(OH)D] (ng/ml) levels among three groups: children and adolescents (3–16 years) with CTD (n = 327); first-degree relatives (3–10 years) of individuals with CTD who were assessed for a period of up to 7 years for possible onset of tics and developed tics within this period (n = 31); and first-degree relatives who did not develop tics and were ≥ 10 years old at their last assessment (n = 93). The relationship between 25(OH)D and the presence and severity of tics, as well as comorbid obsessive–compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD), were analysed controlling for age, sex, season, centre, latitude, family relatedness, and comorbidities. When comparing the CTD cohort to the unaffected cohort, the observed result was contrary to the one expected: a 10 ng/ml increase in 25(OH)D was associated with higher odds of having CTD (OR 2.08, 95% CI 1.27–3.42, p < 0.01). There was no association between 25(OH)D and tic severity. However, a 10 ng/ml increase in 25(OH)D was associated with lower odds of having comorbid ADHD within the CTD cohort (OR 0.55, 95% CI 0.36–0.84, p = 0.01) and was inversely associated with ADHD symptom severity (β = − 2.52, 95% CI − 4.16–0.88, p < 0.01). In conclusion, lower vitamin D levels were not associated with a higher presence or severity of tics but were associated with the presence and severity of comorbid ADHD in children and adolescents with CTD.