Hair Zinc and Severity of Symptoms Are Increased in Children with Attention Deficit and Hyperactivity Disorder: a Hair Multi-Element Profile Study

Abstract

Determination of bioelement levels in hair is an emerging non-invasive approach for screening bioelement deposition. However, the role of essential bioelement levels in hair and attention deficit/hyperactivity disorder (ADHD) risk or severity is largely unknown. In this study, we have compared multi-element hair profiles between healthy and ADHD Thai children. In addition, the correlations between bioelements and ADHD symptoms according to Diagnostic and Statistical Manual of Mental Disorders, 5th edition, diagnostic criteria were identified. A case-control study was conducted in 111 Thai children (45 newly diagnosed ADHD and 66 matched healthy), aged 3-7 years, living in Bangkok and suburban areas. Levels of 39 bioelements in hair were measured by ICP-MS. Among the analyzed bioelements, Cu/Zn and P/Zn ratios in ADHD children were significantly lower than those in healthy children. Indeed, increased hair Zn level was correlated with more symptoms of inattention, hyperactivity, and total ADHD symptoms. Higher Zn content was also associated with being female and older age. Furthermore, Zn in hair was positively correlated with levels of Ca, Mg, and P; however, it showed a negative correlation with Al, As, Fe, and Mo. These findings warrant further confirmation in a large-scale study. Thai Clinical Trials Registry (TCTR) study ID: 20151113001.

Zinc status in attention-deficit/hyperactivity disorder: a systematic review and meta-analysis of observational studies

“…Three studies were excluded due to unavailability of information regarding zinc levels 19 – 21 and two studies were excluded due to lack of reporting information in case and control groups separately and reporting the level of zinc in hemoglobin 22 , 23 . Finally, 22 articles were included in this meta-analysis, 14 studies assessed circulating levels of zinc 13 , 24 – 36 and 8 studies reported hair zinc levels 12 , 37 – 43 .

Figure 1 PRISMA flowchart describing the study’s systematic literature search and study selection.

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“…Except for one study 24 in which both case and control groups had diabetes, other studies used healthy individuals and people with ADHD as control and case groups, respectively. Of the available studies, four were conducted in Egypt 24 , 28 , 29 , 33 , three in Russia 13 , 37 , 38 , two in Turkey 32 , 36 , two in the United States 34 , 41 , and others in Syria 25 , China 26 , Iran 27 , Slovakia 30 , Israel 31 , Saudi Arabia 35 , New Zealand 39 , Indonesia 40 , Thailand 12 , Korea 42 , and Georgia 43 . Twenty studies had case–control design and only two studies 13 , 28 were conducted by cross-sectional design.…”

“…Results of previous reports regarding the relationship between zinc levels and ADHD are inconsistent. Tippairote et al in a case–control study, showed that higher hair zinc level was associated with greater ADHD symptoms and inattention 12 . On the other hand, Skalny et al showed that lower levels of zinc and magnesium may significantly contribute to the severity of ADHD symptoms 13 .…”

The Effect of Plumbum, Zinc and Zinc Ratio on Plumbum in Children’s Temperament

“…Children are not quite active and moody but only show moderate disorder in terms of function. Children are more susceptible to behavioral problems at the beginning and middle of childhood (13,17) . Parenting is a process of introducing and supporting a child's physical, emotional, social and intellectual development from a baby to an adult.. Another aspect is that parenting is the interaction between children and caregivers during care, including the process of developing appropriate knowledge and skills for children, ways to educate by giving rules and restrictions applied to their children, maintenance, instilling trust, how to get along, attitudes create an emotional atmosphere, protection and teach general behavior that can be accepted by society.…”

“…Melatonin is a hormone secreted by the pineal glandule and is tasked with regulating the rhythm of the circadian cycle which is responsible for regulating the human sleep cycle. Children with emotional disorders often experience sleep disorders that are thought to be caused due to melatonin deficiency (17,29) . Zinc also acts as a precursor in the synthesis of tryptophan.…”