Hair zinc level in Down syndrome
Ayse Yenigun, Ferda Ozkinay, Ozgur Cogulu, Canan Coker, Nurten Cetiner, Gonca Ozden, Oguz Aksu and Cihangir Ozkinay
Immunological, endocrinological, and haematological abnormalities are relatively
common in people with Down syndrome (Cuadrado & Barrena, 1996; Decoq & Vincker, 1995; Hestnes
et al., 1991; Sustrova & Strbak, 1994; Nespoli, Burgio, Ugazio & Maccario, 1993; Kempski, Chessells
& Reeves, 1997; Kivivuori, Rajantie, & Siimes, 1996; David et al., 1996; Gjertson, Sturm & Berger,
1999). Zinc is one of the elements that act in the maintenance of normal function of these systems.
This study was designed to investigate zinc levels in children with Down syndrome. Zinc levels
were measured in hair using atomic absorption spectrophotometry. The hair zinc level of 19 children
with Down syndrome was compared with the zinc level of 11 typically developing children. Hair
zinc levels were found to be significantly lower (p < .05) in those with Down syndrome (average
95.18 ± 56.10 ppm) than in the typically developing children (average 208.88 ± 152.37 ppm).
Some of the problems experienced by children with Down syndrome may be due to these low zinc
levels, but further research is required to confirm these results, and to establish any correlation
with these problems.
Yenigun A, Ozkinay F, Cogulu O, Coker C, Cetiner N, Ozden G, Aksu O, Ozkinay C. Hair zinc level in Down syndrome. Down Syndrome Research and Practice. 2004;9(2);53-57.
doi:10.3104/reports.292
Introduction
Zinc is an important element in protein synthesis and gene expression involving the immune and
endocrinological systems. Zinc deficiency may play a crucial role in some of the pathological
manifestations associated with Down syndrome such as infections and malfunctioning of the thyroid
gland (Bjorksten et al, 1980;
Sustrova, & Strbak, 1994).
There have been a number of studies showing that low zinc levels occur in many children with
Down syndrome and that oral zinc supplementation may be useful in correcting some of the immune
and endocrinological disorders associated with thyroid dysregulation in these children (Franceschi
et al., 1988; Kadrabova, Madaric, Sustrova & Ginter, 1996;
Licastro et al., 1994;
Licastro et
al., 1992).
It has been reported that oral zinc supplementation is effective in normalising plasma zinc
levels, thymulin and TSH levels in children with Down syndrome with zinc deficiency (Licastro
et al., 1994; Licastro et al., 1992). Clinical evaluation of children with Down syndrome has
also shown that zinc supplementation decreased the incidence of infectious diseases, and improved
school performance (Franceschi et al., 1988;
Licastro et al., 1992).
Hair was used as a biopsy material reflecting the elemental status of the body (Schlegel-Zawadzka,
Zachwieja, Huzior-Baajewicz & Pietrzyk, 2002;
Misra, Srivastava & Chawla, 1989;
Chen, Lin, Lin
& Cheng, 1988; Cavdar, Bahceci, Akar, Dincer & Erten, 1991). Trace elements in hair, in particular
zinc, are being widely investigated (Deeming & Weber, 1977;
Deeming & Weber, 1978;
Delves, 1985; Kozielec, Starobrat & Kotkowiak, 1994;
Litzman, Dastych & Hegar, 1995). Low hair zinc level
has been shown to be a good indicator of mild to moderate zinc deficiency (Prasad, 1983;
Davies,
1984; Passwater & Cranton, 1983;
Hambridge, 1982). Nevertheless hair zinc level is elevated
due to impaired hair growth in severe zinc deficiencies (Davies, 1984;
Passwater & Cranton,
1983).
In this study we aimed to evaluate the zinc level in children with Down syndrome using hair,
which is easily and non-invasively obtained. We also compared the hair zinc levels of children
with Down syndrome with typically developing children.
Methods and Materials
Hair samples were collected from the suboccipital area (the base of the back of skull), by cutting
with stainless steel scissors, of 19 children with Down syndrome (age range: 2-6 years old)
and 11 age matched typically developing children. The proximal ends of the samples of hair were
usually within 2 cm of the scalp, approximately 0.3 g, were used for the analysis. In each of
these samples the procedures described below were applied.
Acetone-water wash: Hair samples were placed in 100 ml beakers, covered with bidistilled-deionized
water and agitated for 10 minutes with a mechanical shaker. The water was then decanted and
replaced with acetone (Merck 13).
The samples were washed four times with acetone each being agitated for a period of 10 minutes
and subsequently rinsed with water. After being washed the hair samples were dried at 60°C for
16 hours followed by cooling to room temperature and finally reweighed on an analytical balance.
Wet digestion: hair samples were placed in 100 ml wide mouthed pyrex beakers and left to digest
in 5 ml reagent grade nitric acid (Merck 925) overnight. The following morning 10 ml of perchloric
acid (Merck 519): nitric acid (1/4 by volume) was added. All samples were covered with watch
glasses and refluxed at 200°C for about 8 hours until a clear residue of 2-3 ml remained. After
cooling for one hour the digested samples were decanted into 25 ml volumetric flasks and brought
to volume with added rinsings of bidistiled-deiodinized water.
Zinc measurements were done by atomic absorption spectrometry (AAS), using a Pye Unicam SP9.
The zinc hollow cathode lamp current was 5 mA and the wave length was 213.9 nm, slit width 0.5
nm. Results were expressed in parts per million (ppm).
Mean ± standard error of mean values of Zn of both groups in hair were calculated for each group.
Anova analysis was used to compare both groups. The 95% confidence interval (CI) on the mean
was calculated. Chi-square test was used to compare the cases out of 95% CI.
The statistical analyses of the results were calculated in SPSS for Windows.
Results
The results of zinc concentrations of both groups and the comparison of hair zinc levels are
presented in Table 1. The mean zinc level was 95.18 ± 56.10 ppm (range: 19.60-191.50) in Down
syndrome children, and 208.88 ± 152.37 ppm (range: 52.41-558.53) in typically developing children.
Zinc concentrations in hair samples of children with Down syndrome were significantly lower
than the typically developing children (F(1,28)=8.732 ,
p < .05). The
95% confidence interval of the group of typically developing cases was 102.36 ppm. The number
of Down syndrome and typically developing cases out of the lower limit of 95% CI (106.52 ppm)
is shown in Table 2. There was no significant difference between the number of Down syndrome
and typically developing cases below 95% CI (X2=1.824, df=1, ns).
|
Children with Down syndrome |
Typically developing children |
|
Case |
Zinc (ppm) |
Case |
Zinc (ppm) |
|
1 |
27.22 |
1 |
329.71 |
|
2 |
130.11 |
2 |
256.67 |
|
3 |
34.00 |
3 |
558.53 |
|
4 |
62.32 |
4 |
107.25 |
|
5 |
135.29 |
5 |
154.30 |
|
6 |
153.53 |
6 |
78.24 |
|
7 |
52.00 |
7 |
201.74 |
|
8 |
46.44 |
8 |
76.96 |
|
9 |
137.70 |
9 |
52.41 |
|
10 |
60.20 |
10 |
144.33 |
|
11 |
161.00 |
11 |
337.53 |
|
12 |
90.40 |
|
|
|
13 |
52.70 |
|
|
|
14 |
147.86 |
|
|
|
15 |
162.14 |
|
|
|
16 |
19.60 |
|
|
|
17 |
118.20 |
|
|
|
18 |
26.19 |
|
|
|
19 |
191.50 |
|
|
(a)
|
Hair zinc levels (ppm) |
|
mean ± SD |
SEM |
Range |
|
Children with Down syndrome
(n = 19) |
95.18 ± 56.10 |
12.87 |
19.60-191.50 |
|
Typically developing children
(n = 11) |
208.88 ± 152.37 |
45.94 |
52.41-558.53 |
(b)
Table 1 | (a) The levels of hair zinc in Down syndrome and typically developing children (b)
The mean, SEM and range of zinc levels in Down syndrome and typically developing children
|
Down syndrome |
Typically developing |
|
Lower * |
10 |
3 |
|
Within |
9 |
8 |
* The number of children below 95% CI
Table 2 | The number of cases below / within 95% confidence interval for zinc levels
Discussion
In the present study we used hair to evaluate the zinc levels in children with Down syndrome.
We found hair zinc levels of children with Down syndrome were significantly lower than those
of the typically developing children. Zinc is an important trace element in metabolism, growth
and development and reproduction. It is a constituent of many enzymes. Zinc also plays important
roles in nucleic acid metabolism and protein synthesis as well as membrane structure and function.
Its deficiency causes impaired growth, poor appetite and physiological changes. Zinc deficiency
is also associated with low levels of antibodies.
Sustrova and Strbak (1994) reported a high
occurrence rate of complex immune and endocrine disorders with thyroid dysregulation in people
with Down syndrome, with zinc deficiency playing a considerable role. There is a susceptibility
to respiratory infection in children with Down syndrome, and this is one of the major factors
in their early mortality. A number of investigations including zinc status have been performed
to prevent these infections (Teksen, Sayli, Aydin, Sayal & Işimer, 1998). It has been found
that zinc deficiency plays an important role in immunglobulin concentrations and thyroid function
(Franceschi et al., 1988;
Licastro et al., 1994;
Licastro et al., 1992;
Sustrova & Strbak, 1994).
However no significant difference was also found between children with Down syndrome with normal
zinc levels and low zinc levels regarding the measures of growth hormone secretion, Ig A and
Ig G antigliadin antibodies, presence of celiac disease, thyroid function tests, CD4/CD8 ratio
and total immunoglobulins in another study (Romano et al., 2002). Hair zinc level has also been
evaluated in a range of different clinical situations. Mean hair and serum zinc levels were
found to be much lower in Indian childhood cirrhosis than the age-matched healthy controls (Misra,
Srivastava & Chawla, 1989). Chen et al. (1988) found the serum and hair zinc controls in obese
patients markedly lower than in non-obese patients.
Litzman et al. (1995) found a significant
decrease in serum zinc levels in common variable immunodeficiency patients. It was found that
zinc therapy not only improves the immune system, but also accelerates growth (Napolitano, et
al., 1990). Kozielec et al. (1994) showed that it was necessary to supplement trace elements
in children with hyperactivity.
Zinc status can be evaluated by using serum, urine, saliva and hair. Although body fluids and
tissues are commonly used methods, no correlation has been found between those specimens (Delves,
1985). Hair may be used as a biopsy material reflecting the level of zinc status of the body.
Deeming and Weber (1977) evaluated hair analysis for determination of zinc status using rats
and reported that hair zinc analysis could be used to aid diagnosis of a deficiency or evaluate
dietary intake. Furthermore once incorporated into hair, zinc is no longer in equilibrium with
the body and therefore not susceptible to circadian variation (Coker, Cetiner, Sozmen & Ersoz,
1996; Yenigun, Oksel, Bozdogan & Taneli, 1996;
Yenigun, Taneli & Kultursay, 1991). The advantages
of hair as a source are that it is easy to obtain and stable in storage. It is not affected
from the daily variations of food intake. On the other hand, there is a lack of concordance
in the results of different laboratories in the assessment and analysis of zinc deficiency (Capel,
Spencer, Daivies & Levitt, 1985; Deeming & Weber, 1978;
Delves, 1985; Lockitch et al., 1989).
It has been reported that hair zinc level reflects the body zinc level (Bilir, Kayakirilmaz,
Guven, Atik & Ugurlu, 1987; Chen et al., 1985;
Klevay, 1970). Deeming & Weber (1978) reported
that mineral concentration of hair, serum and diet do not correlate well. Age, sex and body
mass index have been reported to be some of the influencing factors that affect the concentration
of zinc in the hair (Chen et al., 1985;
de Mateo, Perez & Mijan de la Torre, 2000).
Klevay (1970)
suggested the use of hair as a biopsy material in the evaluation of zinc status by comparing
the levels to an age-matched typically developing control group. Our control group was age-matched
with the study group, which ranged between 2-6 years old. However, food habits and frequency
of intake of different products also influence zinc concentration in hair (Schlegel-Zawadzka
et al., 2002; Deeming & Weber, 1978).
These findings indicate that zinc level is influenced by a number of external and internal factors
and correction of the zinc level is necessary for the control of biological processes in children
with Down syndrome who are vulnerable to zinc deficiency. Therefore zinc level for an individual
with Down syndrome may be judged to be deficient after comparing with the age-matched control
group from the similar environment. Hair zinc level was investigated in a few studies and ranged
between 118 and 152 microgram/g. The mean level of typically developing children was found to
be 208.88 ± 152.37 ppm in the present study. Coker et al.
(1996) analyzed hair zinc levels in
24 typically developing children and found a similar mean value to the present study (238.5
microgram/g). The mean hair zinc level in our study was 95.18 ± 56.10 ppm in children with Down
syndrome. Accepting the hair zinc values outside of a 95% confidence interval from typically
developing children to be abnormal, there is no significant difference between the two groups
in the current study. De Mateo et al. (2000) analyzed the zinc status in a healthy, adult, Spanish
population. A predictive model of multiple regression was obtained for zinc in hair which is
associated with age, sex and BMI. Similar investigations with larger study groups for different
populations may be helpful to standardize the hair zinc level, which is an easily obtained and
non-invasive biopsy material.
In conclusion, we aimed to investigate the levels of hair zinc in children with Down syndrome
by comparison with typically developing controls, therefore we cannot comment on the usefulness
of zinc supplementation for children with Down syndrome. Nevertheless zinc supplementation may
be useful at least in individuals with Down syndrome with lower hair zinc levels, which is recommended
by many authors to reduce the incidence of problems such as infections and endocrinological
but further clinical research is required to support this suggestion.
Correspondence
Ozgur Cogulu, MD • Ege University Faculty of Medicine, Department of Pediatrics, 35100 Bornova,
İzmir, Turkey • Tel. +90-232-339 81 98 • Fax. +90 232 339 87 81 • e-mail: cogulu@med.ege.edu.tr
References
- Bilir, S., Kayakirilmaz, K., Guven, N., Atik B. & Ugurlu M. (1987). Down sendromlu çocuklarda
serumda ve saçta çinko, bakır ve demir düzeylerinin tayini ve fiziksel gelişim durumlarının
normal çocuklarla karşılaştırılması. (Turkish) (Determination of zinc, copper, and iron
levels of hair and serum in Down syndrome children and comparison of development with the
normal children). Çocuk gelişimi ve eğitim dergisi (Journal of Child Development and
Education), 2, 9-23.
- Bjorksten, B., Back, O., Gustavson, K.H., Hallmans, G., Hagglof, B. & Tarnvik, A. (1980).
Zinc and immune function in Down's syndrome. Acta Paediatrica Scandinavica, 69, 183-7.
- Capel, I.D., Spencer, E.P., Daivies, A.E. & Levitt, H.N. (1985). The assessment of zinc
status by the zinc tolerance test in various groups of patients. Journal of Clinical
Endocrinology and Metabolism, 14, 725-60.
- Cavdar, A.O., Bahceci, M., Akar, N., Dincer, F.N. & Erten, J. (1991). Maternal hair zinc
concentration in neural tube defects in Turkey. Biological Trace Element Research,
30, 81-5.
- Chen, M.D., Lin, P.Y., Lin, W.H. & Cheng, V. (1988). Zinc in hair and serum of obese individuals
in Taiwan. American Journal of Clinical Nutrition, 48, 1307-9.
- Chen, X.C., Yin, T.A., He, J.S., Ma, Q.Y., Han, Z.M. & Li, L.X. (1985). Low levels of zinc
in hair and blood, pica, anorexia and poor growth in Chinese preschool children.
American
Journal of Clinical Nutrition, 42, 694-700.
- Coker, C., Cetiner, N., Sozmen, E. & Ersoz, B. (1996). Analysis of hair copper and zinc.
Medical Journal of Ege University, 6, 1-3.
- Cuadrado, E. & Barrena, M.J. (1996). Immune dysfunction in Down's syndrome: primary immune
deficiency or early senescence of the immune system? Clinical Immunology and Immunopathology,
78, 209-14.
- David, O., Fiorucci, G.C., Tosi, M.T., Altare, F., Valori, A., Saracco, P., Asinardi, P.,
Ramenghi, U. & Gabutti, V. (1996). Hematological studies in children with Down syndrome.
Pediatric Hematology and Oncology, 13, 271-5.
- Davies, S. (1984). Assessment of zinc status.
International Clinical Nutrition Review,
4, 122-9.
- de Mateo, S.B., Perez, G.A. & Mijan de la Torre, A. (2000). The zinc status in a selected
Spanish population. A multivariate analysis. Nutrición Hospitalaria, 15, 32-41.
- Decoq, P. & Vinckier, F. (1995). Down syndrome: 1. Medical aspects.
Revue Belge de Medecine
Dentaire, 50, 43-52.
- Deeming, S.B. & Weber, C.W. (1977). Evaluation of hair analysis for determination of zinc
status using rats. American Journal of Clinical Nutrition, 30, 2047-52.
- Deeming, S.B. & Weber, C.W. (1978). Hair analysis of trace minerals in human subjects as
influenced by age, sex, and contraceptive drugs. American Journal of Clinical Nutrition,
31, 1175-80.
- Delves, H.T. (1985). Assessment of trace element status.
Journal of Clinical Endocrinology
and Metabolism, 14, 725-60.
- Franceschi, C., Chiricolo, M., Licastro, F., Zannotti, M., Masi, M., Mocchegiani, E. & Fabris,
N. (1988). Oral zinc supplementation in Down's syndrome: restoration of thymic endocrine
activity and of some immune defects. Journal of Mental Deficiency Research, 32, 169-81.
- Gjertson, C., Sturm, K.S. & Berger, C.N. (1999). Hematopoietic deficiencies and core binding
factor expression in murine Ts16, an animal model for Down syndrome.
Clinical Immunology,
91, 50-60.
- Hambridge, K. (1982). Hair analysis: Worthless for vitamins, limited for minerals.
American
Journal of Clinical Nutrition, 36, 943-9.
- Hestnes, A., Stovner, L.J., Husoy, O., Folling, I., Fougner, K. J. & Sjaastad, O. (1991).
Hormonal and biochemical disturbances in Down's syndrome. Journal of Mental Deficiency
Research, 35, 179-93.
- Kadrabova, J., Madaric, A., Sustrova, M. & Ginter E. (1996). Changed serum trace element
profile in Down's syndrome. Biological Trace Element Research, 54, 201-6.
- Kempski, H.M., Chesells, J.M. & Reeves, B.R. (1997). Deletions of chromosome 21 restricted
to the leukemic cells of children with Down syndrome and leukemia.
Leukemia, 11,
1973-7.
- Kivivuori, S.M., Rajantie, J. & Siimes, M.A. (1996). Peripheral blood cell counts in infants
with Down's syndrome. Clinical Genetics, 49, 15-9.
- Klevay, L.M. (1970). Hair as a biopsy material. I, Assestment of zinc nutriture.
American
Journal of Clinical Nutrition, 23, 284-9.
- Kozielec, T., Starobrat, H.B. & Kotkowiak, L. (1994). Deficiency of certain trace elements
in children with hyperactivity. Psychiatria Polska, 28, 345-53.
- Licastro, F., Chiricolo, M., Mocchegiani, E., Fabris, N., Zannoti, M., Beltrandi , E., Mancini,
R., Parente, R., Arena, G. & Masi, M. (1994). Oral zinc supplementation in Down's syndrome
subjects decreased infections and normalized some humoral and cellular immune parameters.
Journal of Intellectual Disability Research, 38, 149-62.
- Licastro, F., Mocchegiani, E., Zannotti, M., Arena, G., Masi, M. & Fabris, N. (1992). Zinc
affects the metabolism of thyroid hormones in children with Down's syndrome: normalization
of thyroid stimulating hormone and of reversal triiodothyronine plasmic levels by dietary
zinc supplementation. International Journal of Neuroscience, 65, 259-68.
- Litzman, J., Dastych, M. & Hegar, P. (1995). Analysis of zinc, iron and copper serum levels
in patients with common variable immunodeficiency. Allergologia et Immunopathologia (Madrid),
23, 117-20.
- Lockitch, G., Puterman, M., Godolphin, W., Sheps, S., Tingle, A.J. & Quigley, G. (1989).
Infection and immunity in Down syndrome: a trial of long-term low oral doses of zinc.
Journal of Pediatrics, 114, 781-7.
- Misra, P.K., Srivastava, K.L. & Chawla, A.C. (1989). Serum and hair zinc in Indian childhood
cirrhosis. Indian Pediatrics, 26, 22-5.
- Napolitano, G., Palka, G., Grimaldi, S., Giuliani, C., Laglia, G., Calabrese, G., Satta,
M.A., Neri, G. & Monaco, F. (1990). Growth delay in Down syndrome and zinc sulphate supplementation.
American Journal of Medical Genetics Supplement, 7, 63-5.
- Nespoli, L., Burgio, G.R., Ugazio, A.G. & Maccario, R. (1993). Immunological features of
Down's syndrome: a review. Journal of Intellectual Disability Research, 37, 543-51.
- Passwater, R. & Cranton E. (1983).
Trace elements, hair analysis and nutrition. New
Canaan, Connecticut: Keats Publishing Inc.
- Prasad, A. (1983). Clinical, biochemical and nutritional spectrum of zinc deficiency in
human subjects. An update. Nutrition Reviews, 41, 197-208.
- Romano, C., Pettinato, R., Ragusa, L., Barone, C., Alberti, A. & Failla, P. (2002). Is there
a relationship between zinc and the peculiar comorbidities of Down syndrome?
Down Syndrome
Research and Practice, 8(1), 25-8. [Open
Access Full Text
]
- Schlegel-Zawadzka, M., Zachwieja, Z., Huzior-Baajewicz, A. & Pietrzyk, J.J. (2002). Comparative
analysis of zinc status, food products' frequency intake and food habits of 11-year-old
healthy children. Food Additives and Contaminants, 19, 963-8.
- Sustrova, M. & Strbak, V. (1994). Thyroid function and plasma immunoglobulins in subjects
with Down's syndrome (DS) during ontogenesis and zinc therapy. Journal of Endocrinological
Investigation, 17, 385-90.
- Teksen, F., Sayli, B.S., Aydin, A., Sayal, A. & Işimer, A. (1998). Antioxidative metabolism
in Down Syndrome. Biological Trace Element Research, 63, 123-127.
- Yenigun, A., Oksel, F., Bozdogan, N. & Taneli, B. (1996). Zinc in serum and breast milk
in women who felt that their milk supply is depressed. Medical Journal of Ege University,
6, 47-51.
- Yenigun, A., Taneli, B. & Kultursay, N. (1991). Anne sütü ve serum eser elementleri arasındaki
ilişki (Turkish) (Relations between breast milk and serum trace elements).
Ege Tıp Dergisi
(Medical Journal of Ege University), 30, 389-391.