Age-Based Differences in Hair Zinc of Vancouver Preschoolers

Marginal zinc deficiency (MZD), the subclinical stage of zinc deficiency, is common in industrialized societies. Serum zinc, the most common biomarker of zinc status, lacks sensitivity and specificity to diagnose this deficiency. Hair zinc, however, is sensitive and specific enough to detect MZD in children. Differences in hair zinc associated with age and sex have been reported. These differences have not been investigated thoroughly; therefore, interpretation of the results of hair analyses is difficult. This cross-sectional study was designed to examine the hair zinc status of a group of Vancouver preschoolers (24–71 months) and assess the age- and sex-based differences in their hair zinc. Hair samples were obtained (n?=?719) and analyzed for zinc using inductively coupled plasma mass spectrometry. Our results indicated a mean hair zinc of 115?±?43 μg/g with 17% below the low hair zinc cutoff (70 μg/g). Boys and girls had comparable mean hair zinc, while girls had a significantly higher occurrence of low hair zinc than boys (21% vs. 12%). Children <4 years of age had significantly lower mean hair zinc and higher rate of low hair zinc compared to children ≥4. Our study provides important reference values for the hair zinc of healthy North American preschoolers.     

Associations of Socio-demographic and Behavioral Variables with Hair Zinc of Vancouver Preschoolers

Marginal zinc deficiency (MZD) exists in children of industrialized societies and impairs growth and development. MZD is believed to be one of the most common deficiencies, even though there is no data available on its global prevalence. This is partly because of the lack of sensitivity and specificity of serum zinc, the most commonly used biomarker of zinc status, to detect MZD. In children, MZD is always accompanied by a decrease in hair zinc. This cross-sectional study was designed to explore if there are any associations between some socio-demographic and behavioral variables with hair zinc status in an attempt to understand the social determinants of MZD and the profile of at risk children. Our citywide survey (n = 719) indicated a mean hair zinc of 116 ± 43 μg/g with 17% below the cutoff. Logistic regression analysis indicated that age, maternal education, number of adults at home, being described as “eating unhealthy”, and Child Behavior Questionnaire scores of “activity level” as the significant predictors of hair zinc status. Our study provides important information on the hair zinc status of Vancouver preschoolers and some factors in children and their environment associated with hair zinc, which may help in better understanding of hair zinc as a biomarker of MZD.     

Prevalence of zinc deficiency in junior high school students of Tehran City

Zinc deficiency is a health problem in many communities especially among adolescents because of pubertal growth sprout. This investigation was carried out to determine the epidemiology of zinc deficiency in junior high school students in Tehran City in 1997. This cross-sectional study was performed on 881 students (452 males and 429 females) with the mean age of 13.2±1.0 yr, who were selected by multistage random sampling method. Plasma, erythrocyte, and hair zinc levels were assayed by flame atomic absorption spectrophotometry. Anthropometric and demographic characteristics were measured and recorded on a questionnaire. Dietary intakes were evaluated by a 24-h recall method. Zinc deficiency was defined as having at least two indices from indices of erythrocyte, plasma, and hair zinc below 10 μg/mL, 100 μg/dL, and 125 μg/g of hair, respectively. The results showed that zinc deficiency prevalence was 31.1% (confidence interval: 28–34.4%). Zinc deficiency was 65%, 49%, and 1.3% based on plasma, erythrocyte, and hair zinc levels, respectively. The mean ± SD for plasma, erythrocyte, and hair zinc concentration, height-for-age, as well as weight-for-age Z scores were 95.2±17.7 μg/dL, 10.3±2.3 μg/mL, 239.4±54.4 μg/g, −0.40±0.92, and 0.12±0.91, respectively. As for dietary intake compared with the RDA, 50% of the subjects consumed less than 50% of their requirement for zinc RDA based on a 24-h dietary recall. Zinc intake in subjects was 7.5±3.7 μg, that in boys was higher than in girls. Correlation coefficients between zinc status indices were very weak. There was neither a linear nor nonlinear relationship between biochemical parameters and nutritional zinc intake. It is concluded that almost one-third to one-half of the subjects would be considered zinc deficient.     

Hair Zinc: an Index for Zinc Status in Under-Five Children from Low-Income Communities in Kanam Area of North-Central Nigeria

Nutritional deficiencies of trace elements are among the top ten causes of death in Sub Saharan Africa. In Kanam Local Government Area of Nigeria, the problem is compounded by high levels of poverty and illiteracy. Abnormally low hair zinc levels are important, sensitive diagnostic biochemical indices of Zinc deficiency. The purpose of this study is to assess the zinc status of children less than 5 years in Kanam local government area, north-central Nigeria, by measuring the zinc level in hair samples collected from 44 under-5 children across the area. A household survey was made to assess the pattern and frequency of consumption of zinc-rich foods which was done by means of questionnaire. Hair samples were analysed for zinc content by the inductively coupled plasma-mass spectrophotometry (ICP-MS). The data were analysed statistically using the Student’s t test, z test, and Pearson correlation, while questionnaire-captured data were analysed by simple arithmetic. The results of the analyses showed that the average hair zinc level was 74.35 ± 48.05 μg/g. This was below the normal range of 130–140 μg/g, for children less than 5 years. Based on the results, 86.36% have hair zinc level below the lower limit of the normal range of 130 μg/g. Between the gender, boys have higher hair zinc content than girls. Data from the questionnaire showed that 53.45% of the population studied have poor/inadequate intake of zinc-rich foods of animal origin, a dietary behaviour reported to predispose to micronutrient deficiency, including zinc.     

Hair zinc and copper: Relationship to hair type and serum concentrations in children and adolescents

The zinc and copper serum and hair concentrations of 691 3-18-y-old girls and boys previously determined as a part of the Multicentre Study of Atherosclerosis Precursors in Finnish Children and Adolescents were further analyzed in order to find a possible association between these two zinc and copper indices. The influence of hair color and the diameter of individual hair strands on hair concentrations were studied by the analysis of covariance. Hair color and serum zinc concentrations were found to be associated with hair zinc concentrations in boys. Such an association was not found for zinc and copper concentrations in girls. Hair vs serum concentrations in different age and hair color groups did not show however, a significant relationship either in copper or in zinc concentrations. The subjects with very low or high serum zinc or copper concentrations did not usually have extreme hair concentrations and vice versa. However, there were some subjects with low or high serum concentrations associated with low or high hair concentrations.     

Erythrocytary zinc and the infant growth profile in northeast Brazil

This study evaluated nutritional status linked to zinc levels in 239 randomly selected children at crèches in Teresina, Brazil, aged 3 to 6. Blood samples were collected after fasting of 10 h. Erythrocytary zinc levels were determined through flame atomic absorption spectrophotometry. Zinc deficiency was determined as below 40 microg Zn/g Hb. Infant linear growth was evaluated measuring weight and height, and nutritional status by height/age, weight/height, and weight/age indices, expressed as Z scores, in line with the National Center for Health Statistics. The mean zinc concentration was 35.50 +/- 10.95 microg Zn/g Hb. Zinc distribution in the 10, 50, 75, and 90 percentiles was 24.73 microg Zn/g Hb, 35.45 microg Zn/g Hb, 40.73 microg Zn/g Hb and 52.77 microg Zn/g Hb, respectively. Based on this distribution, normal values were found only from the 75th percentile and above. Since the cutoff point adopted was 40 microg Zn/g Hb, the prevalence of zinc deficiency was 74.3%. As for growth profile, 8.4% were chronically malnourished, although the statistical association between linear impairment and nutritional status regarding zinc was insignificant. The study revealed that an important segment of the infant population was mineral deficient; however, the degree of deficiency did not influence growth profiles.     

Zinc,copper, and sexual maturation in 9-18-year-old girls and boys

The relationships between serum levels of zinc and copper and sexual maturation were analyzed in 2291 9-18-yr-old Finnish girls and boys. Development of public hair, breasts, and genitalia were used to grade maturation according to Tanner's classification. Serum zinc and sexual maturation were not related. However, 15- and 18-yr-old girls who had matured most slowly had low serum levels of zinc compared with their age mates. Thus, sexual maturation seems not to be affected by zinc deficiency in Finland; effects of zinc status on maturation in some minor groups cannot, however, be excluded. Serum copper levels were associated with age and sexual maturation, which complicates the drawing of conclusions about possible deficiencies.     

Town and Gender Effects on Hair Lead Levels in Children from Three Sardinian Towns (Italy) with Different Environmental Backgrounds

This study reports hair lead (PbH) levels measured in 2002 in 193 children from three Sardinian towns: Carbonia, Gonnesa, and Sinnai. Carbonia and Gonnesa are in a polluted area of Sardinia due to their vicinity to the industrial zone of Portovesme. As a consequence of its economy and location, Sinnai is not exposed to lead pollution. PbH concentrations were determined by inductively coupled plasma atomic absorption spectrometry. The aim of this study was to evaluate if hair is a reliable biomarker to determine different degrees of exposure of populations to lead pollution and if there is a tendency to higher accumulation by males or females. The girls of Carbonia had the highest mean PbH value (2.21 microg/g), followed by the Gonnesa girls (2.03 microg/g), Carbonia boys (1.86 microg/g), Gonnesa boys (0.91 microg/g), and finally the Sinnai boys (0.68 microg/g) and girls (0.50 microg/g). Two-way analysis of covariance, with age as covariate, revealed a significant effect of town and sex on log PbH. Spearman's rank correlation coefficient indicated a significant positive concordance between PbH levels and gender (score for males=1, females=2). The results suggest that hair is a reliable biomarker to determine different levels of exposure of populations to lead pollution, and they indicate that females tend to accumulate lead in the hair more than males of the same age.     

Maternal hair zinc concentration in neural tube defects in Turkey

Hair zinc concentration was measured in samples taken from 57 mothers who delivered infants with neural tube defects (NTD) (mainly anencephaly). Control groups consisted of 30 healthy mothers with normal offspring and 37 nonpregnant women from middle-income backgrounds. Zinc concentration was also measured in the hair of eight infants with NTD (four being anencephalic). The mean maternal hair zinc concentration in the NTD group (128.2 +/- 38.9 micrograms/g) was lower than that of the control women (p less than 0.001), whereas the mean hair zinc level of malformed babies (250.4 +/- 85.2 micrograms/g) was significantly higher than that of normal infants (193.4 +/- 39.2 micrograms/g) (p less than 0.05). Maternal nutritional zinc deficiency was thought to be one of the factors responsible for NTD in Turkey.     

INAA of serum zinc of inhabitants in five regions of the Czech Republic

To investigate the Zn status of inhabitants of the Czech Republic, 1155 serum and 132 hair samples were analyzed for zinc content. Analyzed material was obtained from randomly selected volunteers of both sexes in the age range 6–65 yr. Subpopulations from five regions were included in the study. Analyses of both materials were performed by Instrumental Neutron Activation Analysis (INAA). Coanalyses of Standard Reference Materials (SRM) for quality control were performed. The results (mean 910 ±276 Μg Zn/L serum and 189 ±45 Μg Zn/g hair) demonstrate satisfactory zinc status of the searched population. Significant interregional differences and age-dependent differences, as well as sex-dependent differences have been detected by the use of correlation analysis. On the basis of these results, serum Zn concentration results of individual categories according to age and sex were evaluated, and on the grounds of mean ±2 standard deviations, indicative intervals were calculated. The frequency of individual serum Zn concentrations proved that the population of the Czech Republic does not suffer from severe zinc deficiency. On the other hand, about one-third of our inhabitants has their serum Zn concentrations below the cutoff value of 800 Μg Zn/L serum, which means a marginal or mild Zn deficit of the organism.     

Interrelationship of indices of body composition and zinc status in 11-yr-old New Zealand children

Serum zinc and hair zinc concentrations of some New Zealand children aged 11 yr, were examined in relation to selected anthropometric indices. Serum zinc concentrations (n=453) in boys and girls were similar and were unrelated to anthropometric indices and hair zinc concentrations. Mean hair zinc concentration (n=620) of the girls was higher than that for the boys (2.95±0.49 vs 2.46±0.47 μmol/g; p<0.001). Correlation analysis demonstrated that, for the boys, all the studied anthropometric indices, with the exception of height, were significantly related to hair zinc concentration and that the confounding effects of mid-parent height and the timing of the adolescent growth spurt was small. Results for the girls were similar but less significant. Dichotomizing the hair zinc results divided both the boys and girls into two groups: those with hair zinc <2.44 μmol/g were heavier (girls, 39.0 vs 35.2 kg; boys, 36.6 vs 34.7 kg) and fatter (mid-upper-arm fat area: girls, 15.2 vs 12.0 cm²; boys, 11.1 vs 9.5 cm²) compared to their counterparts with hair zinc >2.44 μmol/g. The results demonstrate that in these healthy New Zealand children, those with lower hair zinc concentrations are fatter and heavier than their high-hair-zinc counterparts.     

Marginal zinc deficiency increases oxidative DNA damage in the prostate after chronic exercise

Approximately 12% of Americans do not consume the recommended level of zinc and could be at risk for marginal zinc deficiency. Zinc functions in antioxidant defense and DNA repair and could be important for prostate health. We hypothesized that marginal zinc deficiency sensitizes the prostate to oxidative stress and DNA damage. Rats were fed a zinc-adequate (ZA; 30 mg Zn/kg) or marginally zinc-deficient (MZD; 5–6 mg Zn/kg) diet for 6 weeks. MZD increased p53 and PARP expression but no change in 8-hydroxy-2′-deoxyguanosine levels was detected. To examine the susceptibility to exogenous oxidative stress, rats fed a ZA or MZD diet were assigned to exercising (EXE) or sedentary (SED) groups for 9 weeks. MZD or EXE alone did not affect oxidative DNA damage in the prostate; however, combined MZD + EXE increased DNA damage in the dorsolateral lobe. PARP and p53 expression was not further induced with MZD + EXE, suggesting that MZD interferes with DNA repair responses to stress. Finally, the addition of phytase to the MZD diet successfully restored zinc levels in the prostate and decreased DNA damage back to ZA levels. Overall, this study suggests that marginal zinc deficiency sensitizes the prostate to oxidative stress and demonstrates the importance of maintaining optimal zinc nutrition in physically active populations.     

Zinc in Thalassemic Patients and Its Relation with Depression

Studies have shown that there is a relationship between zinc levels and depression. Thalassemic patients are at risk of zinc deficiency due to various causes including Desferal injection. The aim of this study, therefore, is to investigate hair zinc levels in thalassemic patients and their association with depression. For the purposes of this survey, 50 patients with major thalassemia between 10-20 years old were selected randomly. The patients' hair zinc concentration was compared with a control group of similarly aged healthy individuals. Simultaneously, their psychological status was evaluated with either the "Beck" or "Marya Kovacs" test (according to age) so that the relation between depression and zinc concentration could be assessed. The mean hair zinc concentration in patients was more than the controls (193.96 +/- 92.4 ppm vs 149.6 +/- 72.21 ppm). Zinc deficiency was present in 10% of the patients, and 52% had some degree of depression. There was a reverse correlation between zinc deficiency and blood transfusion rate (p < 0.05). Also, while there were more incidences of depression among the zinc deficient patients, the difference was not significant. Regarding the high prevalence of depression and insignificant relation to the zinc deficiency in these thalassemic patients, this research suggests the need for further consideration concerning patients' psychological status, the risk factors of zinc deficiency, as well as extended assessment into other causes of depression.     

Changes of zinc values in children during malignant disease

In 47 children with malignancy, zinc status, growth, and performance during standard treatment were compared with those in controls. At diagnosis, growth was retarded and hair zinc values were high, 2.4 +/- 0.7 mumol/g, as in chronic deficiency. During induction therapy, serum declined to 10.4 +/- 2.3 mumol/L and urinary excretion increased to 5.3 +/- 2.8 mumol/mol creatinine, as in acute exacerbation of deficiency. Control CSF values in children in remission, 0.04 +/- 0.01 mumol/L, were lower than reference values in adults. No difference in mean CSF zinc was observed during therapy, or in those with acute lymphoblastic leukemia (1) at high risk, (2) with central nervous system involvement, (3) with low performance, or (4) resistant to therapy. In six children unexplained values, up to 0.28 mumol/L during induction, were measured. No correlations between the various zinc parameters were found.     

Biological monitoring of lead and cadmium in human hair and nail and their correlations with biopsy materials, age and exposure

Hair and fingernails of exposed and unexposed subjects were analyzed for their lead (Pb) and cadmium (Cd) contents by atomic absorption spectrophotometer with graphite furnace and air-acetylene flame. Hair and nail Pb concentrations in occupationally exposed subjects ranged between 1.020-409.726 and 8.130-765.306 microg/g and in environmentally unexposed subjects 0.123-25.160 and 1.076-65.613 microg/g, respectively. Similarly, hair and nail Cd concentrations in occupationally exposed subjects ranged between 0.014-22.086 and 0.214-35.714 microg/g and in environmentally unexposed subjects 0.113-1.627 and 0.028-8.108 microg/g, respectively. A significant correlation was observed between Pb hair and nail concentrations in exposed subjects at P < 0.05, as compared to unexposed subjects and Cd hair and nail in exposed, as well as unexposed subjects. With respect to exposure, levels of Pb in hair and nails were found to be significant in exposed subjects, compared to unexposed ones and levels of Cd were significant only in nails of exposed ones. With respect to age, no significant correlation was found between hair and nail Pb and Cd concentrations in both exposed and unexposed subjects.     

Acquisition of Visuomotor Abilities and Intellectual Quotient in Children Aged 4–10 Years: Relationship with Micronutrient Nutritional Status

Lethargy, poor attention, and the high rate and severity of infections in malnourished children affect their educational achievement. We therefore studied the association between visuomotor abilities and intelligence quotient (IQ) and their relationship with iron, zinc, and copper. A cross-sectional study was carried out on a sample of 89 healthy children (age range, 4-10 years). Evaluations of visuomotor ability and IQ were performed with the Developmental Test of Visual Motor Integration (VMI) and the Scale for Measurement of Intelligence for children aged 3-18 years, respectively. Nutritional status was assessed using anthropometry and biochemical assessments, which included serum ferritin, zinc and copper levels, and Hb. The sample was classified as having low or normal VMI scores: 47 children (52.8%, mean age 7 +/- 1.5 years) had low VMI, and 42 (47.2%, mean age 7 +/- 2.06 years) had normal VMI. There were no statistically significant differences in socioeconomic and cultural condition between both groups. We found significantly higher serum copper and ferritin levels in normal as compared to low VMI, but we did not find any differences with zinc. IQ was significantly higher in normal vs low VMI children. The fact that children with abnormal VMI presented low mean serum copper and ferritin concentrations could indicate that copper and iron deficiencies in this sample could be related with visuomotor abilities.     

Measurement of zinc, copper, manganese, and iron concentrations in hair of pituitary dwarfism patients using flameless atomic absorption spectrophotometry

Pituitary dwarfism (hGHD) is known to be associated with trace element deficiency, which causes improper functioning of the involved endocrine system. Previously, we reported on the head hair concentrations of zinc, copper, manganese, and iron from a total of 418 normal subjects (154 male and 264 female). In this report, we analyzed the head hair concentrations of the same four trace metals of 103 hGHD children (60 male and 43 female) under treatment with human growth hormone (hGH). These subjects ranged in age from 5 to 18 yr. The results were compared with 338 agematched normal subjects (120 male and 218 female). Both male and female hGHD showed approx 1.7 times higher zinc concentrations than normal subjects. Cheruvanky et al. reported a similar trend but with a slightly lower difference between hGHD and normal subjects. The average copper content in the hair of both male and female subjects also showed higher values for the hGHD than for the normal subjects, a trend similar to the values reported by Teraoka et al. In the case of manganese, the concentrations in hair of the hGHD were approx 50% of the values in the normal subjects. Head hair concentrations of iron in the hGHD were commensurate with the normal subjects. Because the content of trace elements in hair varies with the age of subjects, as a control, we investigated the head hair concentration of zinc from 20 healthy girls ranging in age from 10 to 18 yr. The average zinc concentration decreased from 10 to 12 yr, but no clear relation to age was observed from 13 yr and older. These trends were similar to our previous report. The zinc concentration in hair and body weight gain over a year was negatively correlated. The age variation in the content of zinc, copper, manganese, and iron in hair was measured comparing hGHD with the normal subjects in various ages. Concerning the zinc-level variation of hGHD and normal subjects, there were conspicuous differences between hGHD and normal subjects. For copper, the variations in concentration with age were similar to zinc. Regarding the age variations for manganese, hGHD had lower concentrations in hair compared to the normal subjects throughout adolescence (11–18 yr). We have studied the effects between the hair and these trace element concentrations in hGHD before and after hGH administration. These results suggest that hGH affects the metabolism of these trace elements.     

The Concentration of Vanadium in Pathologically Altered Human Kidneys

This study evaluated serum and hair mineral and trace element levels as well as levels of other nutritional factors affecting growth and appetite in young children with non-organic failure to thrive (NOFTT) based on the presence or types of feeding difficulty (FD). Between August 2012 and July 2015, 136 children less than 6 years of age with NOFTT were included. FD was diagnosed based on Wolfson criteria and divided into subtypes according to Chatoor’s classification. Clinical data were reviewed, and serum and hair mineral levels were measured. Of all assessed serum and hair minerals, only hair sulfur contents differed significantly between subjects with and without infantile anorexia (39,392 ± 2211 vs. 40,332 ± 2551 μg/g, P = 0.034). There were no differences in serum and hair mineral levels between children with and without sensory food aversion. Hair copper contents were significantly lower in children with FD of reciprocity (12.3 ± 6.0 vs. 22.4 ± 25.1 μg/g, P = 0.049). While hair zinc contents were also lower, the difference was not statistically significant (49.2 ± 26.8 vs. 70.6 ± 41.0 μg/g, P = 0.055). Only hair manganese contents were significantly lower in children with posttraumatic FD (0.12 ± 0.04 vs. 0.26 ± 0.73 μg/g, P = 0.037). In conclusion, there were no differences in most serum and hair mineral levels in children with NOFTT, except for relatively lower hair levels of sulfur, copper and possibly zinc, and manganese in infantile anorexia, reciprocity, and posttraumatic types of FD, respectively.     

Assessment of Zinc Status in School-Age Children from Rural Areas in China Nutrition and Health Survey 2002 and 2012

Zinc is an essential trace element for growth and development in children, but zinc deficiency is a serious nutritional problem worldwide. Our study aimed to assess the zinc status of school-age children living in rural areas of China and to examine the change of zinc status based on the China Nutrition and Health Survey 2002 and 2012. We used the probability proportional to size sampling method for subject selection, and a total of 3407 school-age children were included in this study. Zinc status was assessed by three items of indicators recommended by the World Health Organization (WHO), the United Nations Children’s Fund (UNICEF), the International Atomic Energy Agency (IAEA), and the International Zinc Nutrition Consultative Group (IZiNCG). The concentration of serum zinc was 718.2 μg/L, and 44.4% of children being zinc deficiency in 2002, while 846.8 μg/L and 10.4% in 2012. Zinc intake was 7.8 mg/day with a 7.6% inadequate zinc intake in 2002, together with 6.9 mg/day and 38.2% in 2012. Height-for-age Z score was ?1.06 and 19.1% of children being stunting in 2002, as well as ?0.15 and 6.8% in 2012. In conclusion, the zinc status of school-age children living in rural areas of China has been significantly improved in addition to zinc intake over the past 10 years. However, the zinc deficiency still observed in poor rural areas of China in 2012. In addition, we suggested that the zinc bioavailability should be taken into account when assessing zinc status in population.