Lead, Cadmium and Zinc in Hair Samples: Relationship with Dietary Habits and Urban Environment E. Gonzalez-Reimers, C. MartínGonzález, L. Galindo-Martín, M. R. Aleman-Valls, J. Velasco-Vázquez, M. Arnay-de-la-Rosa, et al. Biological Trace Element Research ISSN 0163-4984 Biol Trace Elem Res DOI 10.1007/s12011-014-9896-8
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Author's personal copy Biol Trace Elem Res DOI 10.1007/s12011-014-9896-8
Lead, Cadmium and Zinc in Hair Samples: Relationship with Dietary Habits and Urban Environment E. Gonzalez-Reimers & C. Martín-González & L. Galindo-Martín & M. R. Aleman-Valls & J. Velasco-Vázquez & M. Arnay-de-la-Rosa & O. Pérez-Hernández & R. Hernández Luis
Received: 24 November 2013 / Accepted: 10 January 2014 # Springer Science+Business Media New York 2014
Abstract This study was performed in order to analyze the relationships between hair zinc, lead, and cadmium with the kind of diet consumed (by recall of the diet consumed the previous 14 days), living area (urban or rural), tobacco smoking, and body mass index (BMI) among 419 individuals of the Canary Archipelago. Median values and interquartile range were 43 μg/g (18.50–132.50) for zinc, 4.09 μg/g (2.19– 8.38) for lead, and 0.128 μg/g (0.05–0.30) for cadmium. We observed that hair zinc was markedly elevated among those consuming fish more frequently and, to a lesser amount, among those who consumed meat frequently, among those living in urban areas, and among those with BMI over 25 kg/m2, keeping a significant relationship with BMI. Hair lead was also higher among fish consumers, showed a trend to higher values among inhabitants of urban areas, and was lower among obese individuals. Hair cadmium was higher among those who consumed less vegetables and fruits. By multivariate analysis, introducing the variables meat, fish, and vegetable consumption, urban/rural; sex; age; and BMI values, we observed that fish consumption (beta=0.15) was the only variable independently E. Gonzalez-Reimers (*) : C. Martín-González : M. R. Aleman-Valls : O. Pérez-Hernández : R. H. Luis Departamento de Medicina Interna, Hospital Universitario de Canarias, La Laguna, Tenerife, Canary Islands, Spain e-mail: [email protected]
L. Galindo-Martín Departamento de Química Analítica, Universidad de La Laguna, Tenerife, Canary Islands, Spain J. Velasco-Vázquez Departamento de Ciencias Históricas, Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain M. Arnay-de-la-Rosa Departamento de Prehistoria, Antropología e Historia Antigua, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
associated to higher zinc levels; fish consumption (beta=0.15) and meat consumption (beta=0.17) were related to high cadmium levels, whereas meat consumption was significantly associated to higher hair lead levels (beta=0.15). Therefore, we conclude that hair zinc, cadmium, and lead seem to depend more heavily on dietary habits than on tobacco consumption or living in rural or urban areas. Keywords Hair cadmium . Hair zinc . Hair Pb . Dietary habits . Tobacco trace elements . Urban environment . Canary Islands
Introduction Hair trace elements may keep a relation with body stores of these elements. Based on this premise, hair analysis has been used to estimate exposure to some environmental toxic elements such as lead and cadmium [1–3] or to assess the metabolic status of other elements, such as zinc . However, there are discrepancies regarding the relation between hair content and body stores of a given trace element [5, 6] and controversy about the effect of washing procedures and other sources of possible interferences with hair trace element analysis [7, 8]. With these cautions in mind, it is assumed that hair concentration of some trace elements, such as lead, cadmium, as commented, and zinc, may indicate recent exposure to these metals. Although zinc may be also an environmental pollutant  and may cause sideroblastic anemia in cases of high exposure , it is an essential trace element for human beings, heavily involved in antioxidant systems, nutritional status, immune system, cell division, protein synthesis, and muscle metabolism . Meat and fish proteins are the main sources of this element . On the contrary, lead and cadmium are environmental pollutants and may be responsible for
Author's personal copy Gonzalez-Reimers et al.
severe diseases, including neurotoxicity  and osteomalacia secondary to renal disturbances , respectively, as the most outstanding illness derived from increased exposure. Inhalation (tobacco and gasoline exhaust) and/or ingestion (contaminated water and edible products) is the main route for intoxication. Possibly, environmental air pollution is more marked in urban areas than in rural ones . Theoretically, environmental contamination may equally affect vegetables and herbivores, but fish shows the highest cadmium levels . Therefore, dietary habits may exert an influence on the aforementioned trace elements. Also, by incompletely understood mechanisms, obesity may be related to altered body lead  and cadmium  contents. Based on these facts, in this study, we analyze the relationship between hair zinc, cadmium, and lead and dietary pattern, body mass index, tobacco smoking, and living in urban or rural areas in 419 healthy inhabitants of the Canary Islands.
Materials and Methods Subjects Four hundred and nineteen healthy individuals from the Canary Islands were included in the study. The mean age was 30.43±17.17 years old (median=27; interquartile range=20– 39 years). They were recruited among university students, hospital workers, and relatives, who were also subjected to the following questionnaire: By dietary recall, we recorded the number of meals in which meat was consumed during the last 2 weeks, the number of meals in which fish was consumed, and the number of meals in which vegetables and fruit were consumed. For each kind of meal, individuals were classified in two groups (frequent consumers (more than 3 days a week) or nonfrequent consumers). Also, we classified our .population according to body mass index (BMI=weight (in kilogram)/height (in meters squared)) in obese/nonobese (>30 kg/m2) and overweight/not overweight (>25 kg/m2) people. We also recorded if the patients lived in rural areas or urban areas, had a smoking habit and alcohol consumption. Urban areas include Las Palmas (Gran Canaria) and the conurbation Santa Cruz–Laguna (Tenerife). Each of these cities has a population nearing 400,000 inhabitants. In addition, an important oil refinery is located in Santa Cruz de Tenerife. Sample collection was performed by 2009/2010. Methods Scalp hair samples (weight=41 (21–79) mg ; median (interquartile range)) were rinsed in 5-ml Acationox 0.1 % (Scientific Products, McGraw Park, IL) and allowed to dry during one night at 60 °C; once dried, hair samples were rinsed in
acetone and allowed to dry again during one night and were later digested in 5-ml HNO3 (65 % puriss, pro analysi (p.a.) plus suprapur, Fluka, Buchs, Switzerland) using a microwave digestion system (Milestone Ethos Plus Touch Control, Monroe, CT, USA) equipped with polytetrafluoroethylene digestion vessels and a temperature control program; solutions were quantitatively transferred to volumetric flasks and diluted to 25 ml with ultrapure water (Milli-Q Gradient A10 deionization system), and Zn, Cd, and Pb were determined in these solutions. Zinc was measured by flame atomic absorption photometry, using a Varian SpectrAA FS220 spectrophotometer (Victoria, Australia) with deuterium background correction; the detection limit for zinc is 0.009 mg/kg. Cadmium and lead were measured using a graphite furnace and Varian SpectrAA Z220 spectrophotometer, with a Zeeman-effect background correction technique. As a matrix modifier, we used Na2EDTA 0.5 % (p.a., Merck, Darmstadt, Germany). Detection limits for cadmium and lead were 0.05 and 0.02 μg/kg, respectively. Certified patterns containing 1,000 mg/L of each of the trace elements analyzed (Merck, Darmstadt, Germany) were used for calibration and recovery test performance. Details about the analytical procedure are shown in Table 1. Statistics We previously tested whether the concentrations of the trace elements analyzed were distributed normally or not, using the Kolgomorov–Smirnov test. Since they did not follow a Gaussian distribution, we compared differences between men and women; frequent and nonfrequent consumers of meat, fish, and vegetables; between people living in rural and urban areas; obese (BMI>30 kg/m2) and nonobese; and overweight (BMI>25 kg/m2) and nonoverweight persons using Mann– Whitney’s U test. We also compared hair trace element content and age and BMI using Spearman’s rho. Multivariate analyses (stepwise multiple linear regression and logistic regression analyses) were also performed when appropriate.
Results The results regarding trace elements contents are shown in Tables 2 and 3. Differences among men and women were not statistically significant in any of the trace elements analyzed, besides Pb, values observed among women being higher than those obtained for men (Z=2.18; p=0.029). No relation with age was observed, nor with BMI, but those whose BMI was over 25 kg/m2 showed higher hair zinc values (Z=2.67; p= 0.008) than those with BMI