Lead, cadmium and zinc in hair samples: relationship with dietary habits and urban environment.

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/m(2), 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 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.

Bone cadmium and lead in the ancient population from El Hierro, Canary Islands.

This study was performed to determine the levels of lead (Pb) and cadmium (Cd) in 63 bone samples of the prehispanic population of the island El Hierro, comparing them with the values obtained on 98 prehispanic samples from Tenerife, Fuerteventura, Gran Canaria, and La Palma, all of them in the Canary Islands, and with eight modern samples who served as controls. Prehispanic individuals from El Hierro showed the lowest bone Pb values of all the archipelago (0.72+/-1.01 mg/kg), significantly different (F=6.9, p<0.001) from the values obtained for the population of other islands such as Tenerife (4.87+/-5.36 mg/kg) or Fuerteventura (4.45+/-7.85 mg/kg) and also from those of the modern population (30.53+/-14.62 mg/kg). On the other hand, bone Cd, although slightly lower in the ancient population groups, was not significantly different when compared with the modern one. In addition, no differences were observed in bone Cd among the ancient population of the different islands. Bone lead but not cadmium kept an inverse significant relationship with the distance of the burial site both to south Spain (r=-0.31) and Atlantic Morocco (r=-0.28, p<0.001 in both cases).

Dental caries among the pre-Hispanic population from Gran Canaria.

The island of Gran Canaria was inhabited in pre-Hispanic times by people of North African origin who arrived on the island towards the second half of the first millennium BC. In previous studies, we reported that there are some differences between the coastal inhabitants from Gran Canaria, mainly buried in tumuli, and those from the central mountains, mainly buried in caves. For example, the prevalence of auricular exostoses is higher among the population interred in coastal tumuli when compared with the inland population. This finding may be explained by the practice of marine activities, as supported by chroniclers' reports, by archaeological data, and by bone trace-element analysis, which point to a more intense consumption of marine products by the inhabitants of the coastal regions. Dental caries epidemiology is one of the most important ways in which the diet of past populations can be reconstructed. The purpose of this study is to assess the prevalence and intensity of caries among the pre-Hispanic population of Gran Canaria, in order to increase our knowledge about the dietary habits of these people, and to search for differences among the population buried in caves and that buried in tumuli. We studied a total of 791 individuals. Sex was estimated in 561 cases, and age at death, following Brothwell's criteria, in 549. We found that 66.95% of individuals buried in caves and 58.91% of those buried in tumuli showed at least one carious lesion. The proportion of carious teeth was significantly higher among the population buried in caves (median = 15.71%, interquartile range (IR) = 0-33.33%) than among the population buried in tumuli (median = 6.25%, IR = 0-20%, P = 0.001). Type of burial is the main factor associated with the proportion of carious teeth.These data suggest that the population buried in caves had a different dietary pattern from that of those buried in tumuli.

Noninvasive estimation of bone mass in ancient vertebrae.

Histomorphometry is useful in the assessment of trabecular bone mass (TBM), and thus, in the estimation of the prevalence and intensity of osteopenia in ancient population groups. However, it is a destructive method. It is therefore necessary to explore the accuracy of nondestructive approaches, such as radiography, bone mineral density (BMD) assessed by double-energy X-ray absorptiometry (DEXA), bone density (BD), or optical density (OD) in the diagnosis of osteopenia. We selected 51 vertebrae out of a total sample composed of 333 T12, L1, and L2 vertebrae belonging to adult pre-Hispanic inhabitants from El Hierro. These vertebrae underwent histomorphometrical analysis, a fine-grained film radiography with assessment of trabecular pattern following standard methods, OD, DEXA-assessed BMD, and BD. The presence of biconcave vertebrae and wedge-shaped vertebrae was also assessed by measuring anterior height (a), posterior height (p), and height at the middle point of the vertebral body (m), and further calculating the indices 2m/(a + p) ("spine score") and a/p. Significant correlations were observed between TBM and BMD (r=0.43), TBM and BD (r=0.49), TBM and OD (r=0.52), BMD and OD (r=0.51), and BMD and BD (r=0.36), but not between TBM and the indices 2m/(a + p) and a/p. In the stepwise multiple correlation analysis between TBM and BMD, BD, and OD, OD entered into first place and BD into second place, whereas BMD became displaced; the multiple correlation coefficient was 0.63, with a standard error of 3.78. A BMD greater than 0.60 g/cm2, or a bone density greater than 0.60 g/cm3, excluded osteopenia (TBM <15%) with a specificity greater than 90%, whereas a BMD value less than 0.35 g/cm2, a BD less than 0.35 g/cm3, or optical density >1.6 excluded a normal bone mass (TBM >20%) with a specificity greater than 90%. Based on radiographic criteria on the total sample, we also conclude that the overall prevalence of vertebral fractures in the adult pre-Hispanic population of El Hierro of any age is 7.5%.

Bone cadmium and lead in prehistoric inhabitants and domestic animals from Gran Canaria.

Both lead and cadmium exposures derive from natural sources and also from industrialisation and certain habits, such as cigarette smoking in the case of cadmium. Some of these sources only affect human beings. The aim of this study was to determine the levels of lead and cadmium in bone samples of 16 prehispanic inhabitants of Gran Canaria, 24 prehispanic domestic animals (sheep, goat and pigs) from this island, 8 modern individuals, and 13 modern domestic animals. We found that modern individuals showed higher bone Cd values (mean=516.7+/-352.49 microg/kg, range=167.20-1125 microg/kg) than prehistoric ones (mean=85.13+/-128.96 microcg/kg, range=2.97-433 microg/kg). Values of prehistoric individuals did not differ from those of the prehistoric animals (mean=70.54+/-46.86 microg/kg, range=11.06-216.50 microg/kg), but were higher than those of the modern animals (mean=7.31+/-10.35 microg/kg, range=0-35.62 microg/kg). In the same way, modern individuals and modern animals showed approximately 7-fold higher bone Pb than ancient individuals and ancient animals, respectively. Ancient animals showed significantly lower Pb values than all the other groups, whereas modern animals showed Pb values comparable to those of the ancient individuals. A significant correlation was observed between bone Pb and Cd (r=0.61, P<0.001). Since bone cadmium accumulation leads to osteoporosis, we have also tested the relationship between histomorphometrically assessed trabecular bone mass and bone cadmium both in modern and ancient individuals. No significant relationship was found between these two parameters.

Double-energy X-ray absorptiometry in the diagnosis of osteopenia in ancient skeletal remains.

Bone mineral density (BMD) assessed by double-energy X-ray absorptiometry (DEXA) accurately estimates the bone mass in living individuals, and is thus the method usually employed in the diagnosis and follow-up of osteopenia. It is preferred, in clinical settings, to the more invasive and destructive histomorphometrical assessment of trabecular bone mass in undecalcified bone samples. This study was performed in order to examine the value of DEXA-assessed BMD at the proximal end of the right tibia, either alone or in combination with the cortico-medullary index at the midshaft point of the right tibia (CMI), in the diagnosis of osteopenia in a prehistoric sample composed of 95 pre-Hispanic individuals from Gran Canaria. Age at death could be estimated in 34 cases. Diagnosis of osteopenia was performed by histomorphometrical assessment of trabecular bone mass (TBM) in an undecalcified bone section of a small portion of the proximal epiphysis of the right tibia. A high prevalence of osteopenia was found among the population of Gran Canaria. Both TBM and BMD were significantly lower in the older individuals than in younger ones, and BMD was also significantly lower in female individuals. BMD was moderately correlated with TBM (r = +0.51); the correlation was higher if CMI was included (multiple r = +0.615). BMD values lower than 0.7 g/cm2 showed a high specificity (>93%) at excluding normal TBM values. These methods were prospectively applied in a further sample of 21 right tibiae from Gran Canaria, Tenerife, and El Hierro. The results were similar to those obtained in the larger sample. Thus, DEXA-assessed BMD combined with CMI (noninvasive procedures) may be useful in detecting osteopenia in ancient populations.

Auricular exostoses among the prehistoric population of different islands of the Canary archipelago.

It is generally believed that auricular exostoses are due to prolonged exposure to cold water, so their existence in ancient remains may inform us about economic activities in the past. This study was performed to analyze the prevalence of auricular exostoses among 150 pre-Hispanic individuals of different islands of the Canary archipelago. Individuals from Gran Canaria (6/26), Fuerteventura (1/15), and Tenerife (2/64), but not from El Hierro (0/45), showed auricular exostoses, thus supporting the hypothesis of a greater reliance on fishing and shellfishing in the former 3 islands.

Paleonutritional analysis on the prehispanic population from La Palma (Canary Islands).

In this study, we determine bone strontium, barium, and calcium, as well as zinc, copper, and iron, in prehispanic samples belonging to adult individuals from the two main funerary caves from La Palma (Espigón and Barranco Porto), comparing them with our own modern controls. We have found that the Ba/Sr molar ratio of the individuals from Barranco Porto are significantly lower than that of the individuals from Espigón, thus suggesting a consumption of a marine-based diet by the former.

Paleonutritional analysis of the pre-Hispanic population from Fuerteventura (Canary Islands).

In this study, from histological and chemical perspectives, we analyse the human remains belonging to the pre-Hispanic inhabitants from Fuerteventura (one of the Canary Islands) and compare the results with those obtained on a sample of pre-Hispanic inhabitants from Gran Canaria (Canary Islands). We observe that trabecular bone mass was normal in the samples from Fuerteventura except for an elderly woman; this result is in sharp contrast with the decreased bone mass observed in the population from Gran Canaria. The pre-Hispanic population from Fuerteventura showed lower bone strontium, Sr/Ca ratio, and bone barium, but slightly higher bone copper, than that from Gran Canaria. All these data indicate a greater consumption of marine products by the population of Fuerteventura. The high prevalence of osteoporosis observed in the population from Gran Canaria may be interpreted as a consequence of protein-calorie malnutrition, a condition which seemed to be not so prevalent in the population of Fuerteventura.

Auricular exostoses in the prehistoric population of Gran Canaria.

Auditory exostoses are bone anomalies located in the external auditory canal. The bulk of clinical observations and some experimental data support the idea that their development depends on prolonged exposure to cold water. This study was performed in order to analyze the prevalence of auditory exostoses among the prehispanic population of Gran Canaria, comparing it between men and women and between individuals buried in coastal regions and central highlands. We analyzed 323 crania, 41 of which showed auditory exostoses. Marked differences in prevalence were observed between the individuals buried in the central highlands (0.88%) and those buried in coastal regions (40.21%). Among the latter, the prevalence was similar in men (41.67%) and in women (38.89%). These data support the hypothesis that individuals buried in coastal regions performed economic activities related to exploitation of marine resources, whereas those living in the central highlands did not; however, diachronic variation cannot be excluded.

Sex determination by discriminant function analysis of the right tibia in the prehispanic population of the Canary Islands.

This study has been performed in order to define standards usable to determine the sex of prehispanic individuals from the Canary Islands from their skeletal remains. Osteometric information at the right tibia was obtained from 59 complete skeletons from Gran Canaria, housed in the Museo Canario (Las Palmas), 45 males and 14 females (this constitutes the totality of complete prehispanic skeletons known from Gran Canaria). The parameters measured were: tibial length, proximal and distal epiphyseal breadth, transverse and anteroposterior diameter, perimeter at the nutrition foramen levels and minimum shaft perimeter. These parameters were subjected to different SPSS discriminant function analysis, combining all of them, or only the proximal or distal ones, without tibial length, etc., in order to obtain functions usable even if only bone fragments are available. Transverse diameter, proximal epiphyseal breadth and minimum shaft perimeter showed the highest discriminant power. The functions obtained showed high average accuracies, ranging from 94.9 to 98.3%, with female accuracies of 100%. The functions obtained were further applied to a test prehispanic population (ten males and ten females) from El Hierro. Overall accuracies of the functions when applied to this population ranged from 65 to 94.7%, with female accuracies ranging 80% to 100%.

Bone histology of prehistoric inhabitants of the Canary Islands: comparison between El Hierro and Gran Canaria.

The trabecular bone mass (TBM) of the proximal epiphyses of right tibiae belonging to 273 prehispanic inhabitants of Gran Canaria (60. 81% males and 35.53% females) were assessed by histomorphometrical analysis of undecalcified samples and compared with that of 41 samples from El Hierro (52.63% males and 47.37% females). Among the prehispanic population of Gran Canaria 19.05% showed TBM values below 13.5% and 30.40% below 15%, although individual variability was high (range 6.71-35.4%). In sharp contrast with these results, only one case (2.44%) from El Hierro showed a TBM value below 15%, whereas mean TBM (23.50;+/- 5.60%) was significantly higher than that of the population of Gran Canaria (17.88 +/- 5.20%). The high prevalence of osteoporosis on Gran Canaria may reflect protein-calorie malnutrition. Prehistorically Gran Canaria exhibited a relatively high population density (30-40/km(2)) and a strong reliance on agriculture, in contrast with a lower population density (4/km(2)) on the island El Hierro, where the population consumed mainly marine products.

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion.

Strontium metabolism has attracted considerable interest because of to its interaction with calcium, the bone alterations detected after treatment with strontium, and its potential value as a paleodietary indicator. The effects of ethanol on strontium and barium metabolism-another divalent cation which also accumulates in bone--is largely unknown. Based on this fact, we have determined bone content and fecal and urinary excretion of Ba and Sr in four groups of eight animals each pair-fed for 8 wk with (1) a nutritionally adequate diet, (2) a 36% (as energy) ethanol-containing isocaloric diet, (3) a 2% protein, isocaloric diet, and (4) a 36% ethanol, 2% protein isocaloric diet, following the Lieber-DeCarli model. Five additional rats were fed with the control diet ad libitum. We have found that ethanol tends to decrease and a low protein diet to increase bone strontium content; the decrease in bone strontium in the ethanol-fed rats is accompanied by an increase in the absolute excretion of strontium in urine. Ethanol also decreases bone barium content, but the effect of ethanol on urinary barium excretion is opposite that of strontium, a decrease. Thus, we conclude that ethanol alters both barium and strontium metabolism and bone deposition.

Bone lead in the prehistoric population of Gran Canaria.

The present study determined the lead concentration in bone tissue from 40 prehistoric individuals of Gran Canaria, and in a sample of 19 modern day residents of the Canary Islands. Higher bone lead values were observed in the modern sample (18.65 +/- 12.13 &mgr;g/g dry bone tissue) than in the ancient sample (4.41 +/- 3.45 &mgr;g/g dry bone tissue, P < 0.001). Older individuals showed higher bone lead values than younger individuals, but only in the modern group. The correlation between age and bone lead approached statistical significance (P = 0.058). Low bone lead observed in the prehistoric sample suggests a low lead exposure in prehispanic times in Gran Canaria. Am. J. Hum. Biol. 11:405-410, 1999. Copyright 1999 Wiley-Liss, Inc.

Comparison of bone lead in pre-Hispanic, 18th century and modern population of Tenerife.

The present study has been performed in order to determine concentrations of lead in the bone of 14 individuals who were interred towards the beginning of the 18th century at the church 'La Concepción' (Santa Cruz de Tenerife) of 15 Pre-Hispanic individuals of Tenerife and a modern sample for Tenerife, composed of 25 individuals. We have observed higher bone lead values in the modern population than in the ancient one (P = 0.0022), although Pre-Hispanic individuals and those of the 18th century showed similar bone lead values.

Bone trace element pattern in an 18th century population sample of Tenerife (Canary Islands): comparison with a prehistoric one.

We have determined bone strontium (Sr), barium (Ba), calcium (Ca), and zinc (Zn) content in 24 samples belonging to adult individuals who died toward the end of the 18th century and were interred in a church's floor on the island of Tenerife, comparing the results with those obtained in 14 prehistoric samples of the same island and also with those of 7 modern controls. No differences were observed between the two ancient groups, which showed higher bone strontium and barium than the modern sample, and a slightly lower Ba/Sr ratio, thus pointing to consumption of marine sources.

Corticomedular index of the right tibia in the diagnosis of osteopenia in prehistoric skeletal remains.

This study examined the diagnostic accuracy of the corticomedular index obtained at the midpoint of the shaft of right tibia as an indicator of osteopenia in a prehistoric sample composed of 133 individuals. Osteopenia was assessed by a histomorphometrical measure of trabecular bone volume (TBV) in an undecalcified bone section of a small part of the proximal epiphysis to: Mild, moderate, and severe osteopenia were defined as TBV values less than 17.5%, 15%, and 12.5%, respectively. The corticomedular index (CI) was determined on X-ray films of the tibiae. Mean TBV of the sample was 17.93 ± 4.97%, it was moderately correlated with CI (r = 0.43, p < 0.0001). CI values under 0.20 showed high specificity in the diagnosis of all degrees of osteopenia, whereas CI values under 0.275 showed relatively high sensitivity (90.4%) in the diagnosis of severe osteopenia. These methods were then prospectively applied in a further sample of 41 right tibiae also from a prehistoric sample of Gran Canaria. The results were similar to those in the larger sample. Thus, CI may be a useful tool in detecting osteopenia in earlier populations. Am. J. Hum. Biol. 10:37-44, 1998. © 1998 Wiley-Liss, Inc.

Paleodietary analysis on the prehistoric population of El Hierro (Canary Islands).

In order to deepen our knowledge of the dietary habits of the prehispanic inhabitants of El Hierro, we have determined bone strontium (Sr), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), and calcium (Ca) in 52 human tibiae (23 belonging to male and 20 to female individuals) buried in a single burial cave; in 21 modern individuals who served as controls; and in 11 bones of herbivores found at archeological sites of the Canary Islands. Results suggest that females consumed a more vegetarian diet, although site-corrected Sr/Ca ratio of both males and females speaks for a mixed-diet consumption.

Paleodietary analysis on the prehistoric population of El Hierro (Canary Islands).

In order to deepen our knowledge of the dietary habits of the prehispanic inhabitants of El Hierro, we have determined bone strontium (Sr), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), and calcium (Ca) in 52 human tibiae (23 belonging to males and 20 to females individuals) buried in a single burial cave; in 21 modern individuals who served as controls; and in 11 bones of herbivores found at archeological sites of the Canary Islands. Results suggest that females consumed a more vegetarian diet, although site-corrected Sr/Ca ratio of both males and females speaks for a mixed-diet consumption.