Vitamin D Deficiency Among Paediatric Patients with Autism in Malaysia

Background: There is a paucity of studies evaluating vitamin D deficiency and severity of autism. This pilot study determined the prevalence of vitamin D deficiency and insufficiency in paediatric outpatients with autism, under follow up at University of Malaya Medical Centre (UMMC), Kuala Lumpur. This is the first study of its kind involving paediatric patients with autism in South-East Asia.

Objectives: (1) Determine the prevalence of vitamin D deficiency and insufficiency among patients, aged 3 - 16 years, with autism, (2) Compare the severity of autism, as measured via Childhood Autism Rating Scale, 2^nd Edition (CARS-2) scores, in the vitamin D deficient, insufficient and sufficient groups, (3) Compare the severity of behavioural symptoms, as determined by Aberrant Behaviour Checklist, 2^nd Edition (ABC-2) scores according to vitamin D status.

Methods: All patients diagnosed with autism, who presented to the Developmental Paediatrics Clinic, UMMC, during a 2-month period, commencing in September 2018, were included. Socio-demographic data and information regarding risk factors for vitamin D deficiency were obtained. Risk factors that were assessed included age, sex, skin pigmentation, pubertal status, dietary recall, sunlight exposure, physical activity and past history of non-traumatic fractures. The severity of autism was determined via the CARS-2. The ABC-2 was used to assess behavioural symptoms. Serum levels of 25-hydroxy vitamin D, intact parathyroid hormone, phosphate, calcium and alkaline phosphatase were taken. Renal impairment and liver impairment were excluded. The cut-off for vitamin D deficiency was ≤ 35 nmol/L, insufficiency: 36–49 nmol/L and vitamin D sufficiency: ≥ 50 nmol/L. Patients with vitamin D deficiency were commenced on a 3-month course of cholecalciferol, 1200 IU, daily. Patients in this pilot study have been recruited as part of a larger study (n = 100), whereby CARS-2 and ABC-2 scores pre- and post-treatment will be performed to determine whether treatment of vitamin D deficiency reduces the behavioural symptoms of autism.

Results: There were 25 participants (92% male, 8% female). The mean age of participants was 6 years (71.8 months). The prevalence of vitamin D deficiency was 12%, and 32% had vitamin D insufficiency. The mean CARS-2 score was 37.5 (range: 26 - 46.5). The majority (64%) had moderate-to-severe symptoms of autism. Four (16%) had mild-to-moderate symptoms. Table 1 shows the distribution of patients according to CARS-2 severity and vitamin D status. No significant correlation was found between CARS-2 total raw scores or T-scores and vitamin D status. Negative correlations were found between vitamin D levels and the ABC-2 Irritability subscale score (R = -0.24, p = 0.26) and the ABC-2 Hyperactivity/Noncompliance subscale score (R = -0.19, p = 0.36). However, these did not reach a level of statistical significance.

Conclusions: Despite the availability of year-long sunlight in Malaysia, a significant proportion (44%) of patients with autism in the study were either vitamin D insufficient or deficient. CARS-2 and ABC-2 scores were not significantly correlated with vitamin D levels. A larger sample size will be required, as in the follow up study.