J. Velasco-Vázquez

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.

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.

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.

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 μg/g dry bone tissue) than in the ancient sample (4.41 ± 3.45 μg/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.

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).

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.

Bone Cadmium and Lead in 18th Century Population Groups from the Canary Islands

Abstract This study was performed in order to determine the levels of lead and cadmium in bone samples of two historic (18th century) population groups from the Canary Islands (La Concepción and San Francisco), comparing the results with those obtained in modern inhabitants. We found that historic individuals from La Concepción (Tenerife) and San Francisco (Gran Canaria) showed significantly lower bone lead (8.84 ± 13.41 mg/kg and 6.73 ± 4.06 mg/kg, respectively) than the modern population (30.53 ± 14.62 mg/kg). On the contrary, bone cadmium, although slightly lower in the ancient population groups, was not significantly different when compared with the modern one. Bone lead and cadmium kept, however, a significant relationship among the individuals from La Concepción, suggesting a common source of exposure.