Indian Journal of Dental Research

ORIGINAL RESEARCH
Year
: 2019  |  Volume : 30  |  Issue : 1  |  Page : 43--46

Comparative evaluation of salivary zinc concentration in autistic and healthy children in mixed dentition age group-pilot study


Rahul R Deshpande, Pranav Prakash Dungarwal, Komal K Bagde, Priyadarshini S Thakur, Pankti M Gajjar, Ananth P Kamath 
 Department of Pedodontics and Preventive Dentistry, Dr. D. Y. Patil Vidyapeeth's, Dr. D. Y. Patil Dental College and Hospital, Pimpri, Pune, Maharashtra, India

Correspondence Address:
Dr. Pranav Prakash Dungarwal
Department of Pedodontics and Preventive Dentistry, Dr. D. Y. Patil Vidyapeeth's, Dr. D. Y. Patil Dental College and Hospital, Pimpri, Pune - 411 018, Maharashtra
India

Abstract

Context: Autism prevalence is increasing, with current estimates at 1/68–1/50 individuals diagnosed with autism. Diagnosis is based on behavioral assessments. Early diagnosis and intervention are known to greatly improve functional outcomes in people with autism. Diagnosis, treatment monitoring, and prognosis of autistic children's symptoms could be facilitated with biomarkers to complement behavioral assessments. Aims: The aim of this study is to compare and evaluate salivary zinc concentration in saliva samples of autistic and healthy children in mixed dentition age group. Settings and Design: Cross-sectional comparative study carried out in dental college and special child school. Unstimulated whole saliva collected for finding a biomarker. Subjects and Methods: Unstimulated whole saliva sample was collected from 10 autistic and 10 healthy children in mixed dentition age group. Diluted saliva sample was then subjected to inductively coupled plasma emission spectroscopy for the estimation of salivary zinc concentration. Statistical Analysis Used: Mann–Whitney U-test. Results: In children with autism salivary zinc concentration showed a linear equation when compared to healthy children. Conclusions: The low salivary zinc concentration in autistic children can reveal the pathogenesis of autism.



How to cite this article:
Deshpande RR, Dungarwal PP, Bagde KK, Thakur PS, Gajjar PM, Kamath AP. Comparative evaluation of salivary zinc concentration in autistic and healthy children in mixed dentition age group-pilot study.Indian J Dent Res 2019;30:43-46


How to cite this URL:
Deshpande RR, Dungarwal PP, Bagde KK, Thakur PS, Gajjar PM, Kamath AP. Comparative evaluation of salivary zinc concentration in autistic and healthy children in mixed dentition age group-pilot study. Indian J Dent Res [serial online] 2019 [cited 2019 Nov 14 ];30:43-46
Available from: http://www.ijdr.in/text.asp?2019/30/1/43/254528


Full Text

 Introduction



Autism has an estimated prevalence of about 1 in 68 US children, 1 in 42 boys.[1] According to a recent survey study, as many as 1 in 50 children may have autism.[2] Unfortunately, causes of Autism are incompletely understood, and autism in children is often undiagnosed.[3] Current screening tools for autism are based on behavior, and can generate false-positive identification.[4] Treatments for autism have been shown in many studies to be most effective when initiated early;[5] therefore, diagnosis of autism at as early an age as possible is imperative.

Biomarkers for autism could potentially aid in early autism diagnosis and treatment planning. Various previous studies have been done on zinc level in children with autism from various body fluids such as blood, serum, urine, and also from hair follicles, but there are very few studies done on salivary zinc concentration in children with autism. Saliva is an emerging diagnostic oral biofluid because of its simplicity.

Zinc is an essential trace element in humans and animals and is involved in countless metabolic and signaling pathways within the body. However, a particular role of zinc in the immune system and brain has been reported.[6] Zinc is one of the most prevalent metal ions in the brain and participates in the regulation of neurogenesis, neuronal migration, and differentiation, thereby shaping cognitive development and maintaining healthy brain function. Research from the last decades have clearly shown that zinc has a vital role in neonatal development. Zinc deficiency during pregnancy results in specific impairments in the offspring, which have been observed in animal models but might also be present in humans.[7]

As various scientific literatures showed, zinc plays an important role in neurodevelopment and showed deficiency of zinc in children with autism. Therefore, our team has been researching the link between salivary zinc concentration in autistic and healthy children in the mixed dentition age group. We chose the children in mixed dentition age group because the current diagnostic tools for autism are based on cognitive development and behavior of children, which causes delayed diagnosis of autism spectrum disorder (ASD). Since we wanted children who had been diagnosed as autistic at least for a duration of one year, the age group taken was mixed dentition period.

 Subjects and Methods



Criteria for patient selection

In this study, 10 children with autism and 10 normal healthy children ranging from 6 to to 14 years were selected. The autistic children were selected from Ankur Vidyamandir, Pune and had been diagnosed as autistic at least a year back by a pediatrician. They also belonged to the mixed dentition age group. The healthy children selected were from the patients visiting our dental college pediatric dentistry department who were free from any known systemic or local diseases which affect salivary secretions. Only autistic and healthy children with the decayed, missing, and filled teeth (dmft/DMFT) score of 0-3 were taken into the study as different indices would mean a difference in the number of caries per child. We did this to standardize the range of indices present in the children included in the study. After assessing and confirming their health status and caries status, these children were stratified equally into two groups: autistic (10 children ranging from 6 to 12 years), healthy children (10 children ranging from 6 to 12 years). Exclusion criteria included patients who were not willing to be a part of the study. Informed consent forms were obtained from the custodial parent or guardian of the patients after explaining the procedure to the parent or guardian.

Method of saliva collection

To minimize the effect of circadian rhythms, all whole saliva samples were collected 1 h after breakfast for the unstimulated condition.[8] The child was seated in a well-ventilated and well-lit room. The head was kept at 45° flexion with one hand holding onto a 4 ml cryo-precipitation vial with a funnel inserted into it, in a calm atmosphere to simulate unstimulated conditions. The resting whole saliva of the patients will be collected by passive drooling into sterile glass tube, in a quiet well lit room in the morning time. The saliva was allowed to drip into the funnel held to the lower lip. For each trial, the collection continued for 2 min but if the saliva sample was insufficient within 2 min, the collection was continued until 2 ml of saliva per patient was obtained.[9]

Methods of laboratory analysis

For detection of zinc concentration in saliva, the saliva sample obtained from each subject was diluted with distilled water in a proportion of 1:4. This diluted saliva sample was then subjected to inductively coupled plasma emission spectroscopy. The basic aim of analytical atomic spectroscopy is to identify elements and quantify their concentrations in various media. The machine used was Varian Vista Pro with detection limits of 1 ppm for each element.

 Results



The results were tabulated and statistically analyzed using Mann–Whitney U-test. The results were tabulated [Table 1]. Results are statistically nonsignificant.{Table 1}

 Discussion



ASDs are lifelong developmental disabilities. This group of disorders includes autistic disorder, Asperger syndrome, and pervasive developmental delay not otherwise specified. These disorders are presented from birth or very early during development and affect essential human behaviors such as social interaction, the ability to communicate ideas and feelings, imagination, and the establishment of relationships with others.[10]

Autism is diagnosed by looking at a child's behavior and cognition development. No medical tests such as blood tests or biopsies can be performed to diagnose autism disorder. (AD). Diagnosing AD involves a two-step process; the first step is a developmental screening, followed by a comprehensive diagnostic evaluation.[11] However, all these tests can be done when child is above 1 year.

Early diagnosis of autism has many advantages for the child and family which include early information about education and support, earlier access to targeted social, communication, behavioral interventions, and identification of comorbid medical, developmental, and psychiatric conditions.

Bio elements play important roles in the central nervous system. The lack or excess of essential minerals and trace elements are known to cause a variety of health problems and could contribute to the etiology of ASDs.[12] Zinc is one of the most prevalent metal ions in the brain and participates in the regulation of neurogenesis, neuronal migration, and differentiation, thereby shaping cognitive development and maintaining healthy brain function. Zinc deficiency during pregnancy results in specific impairments in the offspring, which have been observed in animal models but might also be present in humans.[7]

Today in the era of nanotechnology and genomics, the field of salivary diagnostics is promising a dramatic change in disease diagnosis and clinical monitoring. It has expanded into detection of cancer, heart and infectious diseases. Today we are using human saliva to detect illicit drugs, alcohol, to measure hormone levels, especially estrogen levels in women suffering from hormone imbalance, endometriosis.[13]

Various previous studies had done on zinc level in children with autism from various body fluids like blood, serum, urine and also from hair follicles, but there are very few studies carried out on salivary zinc concentration in children with autism. As saliva is an emerging diagnostic oral biofluid because its simplicity our team had done a pilot study on salivary zinc concentration in autistic and healthy children in mixed dentition age group.

Li So et al. (2014) conducted a study on serum concentration of copper and zinc in children with ASD with sample size of 60. The results indicated that the mean serum Zn levels and Zn/Cu ratio were significantly lower in children with ASD compared with normal cases, whereas serum Cu levels were significantly higher and concluded that an association between serum levels of Zn and Cu and ASD among Chinese patients, and the Zn/Cu ratio could be considered a biomarker of ASD.[14]

The study results found low salivary zinc concentration in autistic children in comparison with healthy children salivary zinc concentration [Figure 1]. The results were showing linear decreased levels of salivary zinc concentration in autistic children but this was not statistically significant [Figure 2].{Figure 1}{Figure 2}

The low salivary zinc concentration can have a role in the pathogenesis of autism, and this can be a biomarker for diagnosis of autism at early age. Further work is needed to validate these findings in larger numbers of patients with ASD; the result from large sample size could be significant and will help in early diagnosis of ASD. Furthermore, investigations into other trace elements such as copper, magnesium, and mercury is also required.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Wingate M, Kirby RS, Pettygrove S, Cunniff C, Schulz E, Ghosh T, et al. Prevalence of autism spectrum disorder among children aged 8 years – Autism and developmental disabilities monitoring network, 11 sites, United States, 2010. MMWR Surveill Summ 2014;63:1-21.
2Blumberg SJ, Bramlett MD, Kogan MD, Schieve LA, Jones JR, Lu MC. Changes in prevalence of parent-reported autism spectrum disorder in school-aged U.S. children: 2007 to 2011-2012. Natl Health Stat Report 2013;65:1-12.
3Dawson G. Recent advances in research on early detection, causes, biology, and treatment of autism spectrum disorders. Curr Opin Neurol 2010;23:95-6.
4Dereu M, Roeyers H, Raymaekers R, Meirsschaut M, Warreyn P. How useful are screening instruments for toddlers to predict outcome at age 4? General development, language skills, and symptom severity in children with a false positive screen for autism spectrum disorder. Eur Child Adolesc Psychiatry 2012;21:541-51.
5Eikeseth S, Klintwall L, Jahr E, Karlsson P. Outcome for children with autism receiving early and intensive behavioral intervention in mainstream preschool and kindergarten settings. Res Autism Spectr Disord 2012;6:829-35.
6Prasad AS. Impact of the discovery of human zinc deficiency on health. J Trace Elem Med Biol 2014;28:357-63.
7Hagmeyer S, Haderspeck JC, Grabrucker AM. Behavioral impairments in animal models for zinc deficiency. Front Behav Neurosci 2014;8:443.
8Kargul B, Yarat A, Tanboga I. A study of some salivary elements with respect to sex, age and caries in children. Saudi Dent J 1998;10:100-6.
9Wu KP, Ke JY, Chung CY, Chen CL, Hwang TL, Chou MY, et al. Relationship between unstimulated salivary flow rate and saliva composition of healthy children in Taiwan. Chang Gung Med J 2008;31:281-6.
10Bjørklund G. Children with asperger syndrome. Tidsskr Nor Laegeforen 1998;118:1567-9.
11Udhya J, Varadharaja MM, Parthibhan J, Srinivasan I. Autism disorder (AD): An updated review for paediatric dentists. J Clin Diagn Res 2014;8:275-9.
12Lakshmi Priya MD, Geetha A. Level of trace elements (copper, zinc, magnesium and selenium) and toxic elements (lead and mercury) in the hair and nail of children with autism. Biol Trace Elem Res 2011;142:148-58.
13Arunkumar S, Arunkumar JS. Developments in diagnostic applications of saliva in oral and systemic diseases – A comprehensive review. J Sci Innov Res 2014;3:372-87.
14Li SO, Wang JL, Bjørklund G, Zhao WN, Yin CH. Serum copper and zinc levels in individuals with autism spectrum disorders. Neuroreport 2014;25:1216-20.