Society and Health Research Center

Existe creciente evidencia en torno a las asociaciones entre la exposición a riesgo psicosocial laboral y resultados adversos de salud. Objetivo: describir y analizar la presencia de riesgo psicosocial laboral y sintomatología de salud mental en trabajadores no clínicos de un hospital público. Metodología: estudio transversal descriptivo asociativo en trabajadores no clínicos de un hospital público de Santiago (Chile). Se aplicó un cuestionario autoadministrado para evaluar exposición a riesgo psicosocial (modelos demanda-control y desbalance esfuerzo-recompensas). Las variables resultado fueron sintomatología depresiva, ansiosa, y consumo de psicotrópicos. El análisis fue descriptivo y asociativo (prueba exacta de Fisher). Resultados: 47% de los trabajadores presentan alta demanda psicológica, 46% baja autonomía, 61% bajo apoyo social y 75% desbalance entre el esfuerzo invertido y las recompensas percibidas. La prevalencia de sintomatología depresiva y ansiosa en la muestra total f...

La alta prevalencia de obesidad en preescolares y escolares en Chile constituye un problema de salud pública que ha preocupado a las autoridades por su continuo aumento y por su asociación con enfermedades crónicas no transmisibles (ECNT) en la vida adulta (1). El año 2008, la prevalencia de obesidad en escolares de primer año básico de escuelas públicas alcanzó el 20,4 %, según cifras aportados por JUNAEB (2), lo cual ha signiicado un replanteamiento de las metas nutricionales que se pretendía alcanzar el 2010 (de un 16% a un 12%) en esta población de niños (3).

Milk is a major food of global economic importance, and its consumption is regarded as a classic example of gene-culture evolution. Humans have exploited animal milk as a food resource for at least 8500 years, but the origins, spread, and scale of dairying remain poorly understood. Indirect lines of evidence, such as lipid isotopic ratios of pottery residues, faunal mortality profiles, and lactase persistence allele frequencies, provide a partial picture of this process; however, in order to understand how, where, and when humans consumed milk products, it is necessary to link evidence of consumption directly to individuals and their dairy livestock. Here we report the first direct evidence of milk consumption, the whey protein β-lactoglobulin (BLG), preserved in human dental calculus from the Bronze Age (ca. 3000 BCE) to the present day. Using protein tandem mass spectrometry, we demonstrate that BLG is a species-specific biomarker of dairy consumption, and we identify individuals consuming cattle, sheep, and goat milk products in the archaeological record. We then apply this method to human dental calculus from Greenland's medieval Norse colonies, and report a decline of this biomarker leading up to the abandonment of the Norse Greenland colonies in the 15th century CE.

Subject terms: Archaeology
Proteomics
Zoology
Biomarkers

Milk is a major food of global economic importance, and its consumption is regarded as a classic example of gene-culture evolution. Humans have exploited animal milk as a food resource for at least 8500 years, but the origins, spread, and scale of dairying remain poorly understood. Indirect lines of evidence, such as lipid isotopic ratios of pottery residues, faunal mortality profiles, and lactase persistence allele frequencies, provide a partial picture of this process; however, in order to understand how, where, and when humans consumed milk products, it is necessary to link evidence of consumption directly to individuals and their dairy livestock. Here we report the first direct evidence of milk consumption, the whey protein b-lactoglobulin (BLG), preserved in human dental calculus from the Bronze Age (ca. 3000 BCE) to the present day. Using protein tandem mass spectrometry, we demonstrate that BLG is a species-specific biomarker of dairy consumption, and we identify individuals consuming cattle, sheep, and goat milk products in the archaeological record. We then apply this method to human dental calculus from Greenland's medieval Norse colonies, and report a decline of this biomarker leading up to the abandonment of the Norse Greenland colonies in the 15 th century CE. M ilk is a major nutritional resource. In addition to being a source of clean liquid (milk is 80-90% water), milk solids contain approximately 25-55% sugar (lactose), 25-45% fat, and 5-35% protein (caseins and whey proteins), as well as calcium, potassium, and B-vitamins 1 . Adoption of animal milk consumption by humans typically requires behavioral adaptations, such as culturing and curdling techniques, to remove or reduce the lactose content of milk in order to make dairy products digestible after infancy. Additionally, populations with long pastoralist traditions in Europe and India, East Africa, and the Arabian peninsula have also independently evolved lactase persistence (LP), a genetic adaptation in the regulation of the lactase gene (LCT) that allows continued adult digestion of milk 2,3 . LP is hailed as one of the clearest examples of gene-culture co-evolution in humans 4 , yet many fundamental aspects of its evolution remain unknown 5-9 and the socioeconomic context and scale of prehistoric and historic dairying are only poorly understood.

almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The other groups, including the 'Nilo-Saharan language speaking' milk-drinkers, show lower frequencies of LP and lower diversity, and there was a north-east to south-west decline in overall diversity. Amongst the Afro-Asiatic (Cushitic) language speaking Oromo, however, the geographic cline was not evident and the southern pastoralist Borana showed much higher LP frequency and enhancer diversity than the other groups. Together these results reflect the effects of parallel selection, the stochastic processes of the occurrence and spread of the mutations, and time depth of milk drinking tradition.

Objectives: Lactase persistence (LP) is a genetic trait that has been studied among different countries and ethnic
groups. In Latin America, the frequencies of this trait have been shown to vary according to the degree of admixture of
the populations. The objective of this study is to better understand the relationship between this genetic trait and dairy
intake in a multiethnic context through a synthesis of studies conducted in four regions of Chile.
Methods: Genotypes frequencies for the SNP LCT-13910C>T (rs4988235) and frequency of dairy consumption were
obtained from four populations: Polynesians from Easter Island (Rapanui); Amerindians (Mapuche) and Mestizos from
the Araucanıa region; urban Mestizos from Santiago; and rural Mestizos from the Coquimbo region. Genetic differentiation
and association between milk consumption and genotype frequencies were estimated.
Results: Genetic differentiation between Native and Mestizo populations was significant; the LP frequency in
Mapuche and Rapanui was 10% and 25%, respectively, whereas among the Mestizos, LP frequency was near 40%.
Dairy intake was below the nutritional recommendations for the four groups, and extremely below recommendations
among the indigenous populations. Association between milk intake and LP was found in Santiago and Rapanui
populations.
Conclusions: Although the frequency of LP varies among the populations according to their degree of admixture,
dairy consumption was very low across the populations. Given that the association between milk consumption and
expected phenotype was found only in two of the populations analyzed, it seems that lactase non-persistence (LNP) is
not the only cause for dairy avoidance. Thus, it is suggested that SES and cultural preferences are likely affecting dairy
consumption. Am. J. Hum. Biol. 00:000–000, 2015.

The genetic trait of lactase persistence is attributable to allelic variants in an enhancer region upstream of the lactase gene, LCT. To date, five different functional alleles, -13910*T, -13907*G, -13915*G, -14009*G and -14010*C, have been identified. The co-occurrence of several of these alleles in Ethiopian lactose digesters leads to a pattern of sequence diversity characteristic of a 'soft selective sweep'. Here we hypothesise that throughout Africa, where multiple functional alleles co-exist, the enhancer diversity will be greater in groups who are traditional milk drinkers than in non-milk drinkers, as the result of this sort of parallel selection. Samples from 23 distinct groups from 10 different countries were examined. Each group was classified 'Yes 'or 'No' for milk-drinking, and ethnicity, language spoken and geographic location were recorded. Predicted lactase persistence frequency and enhancer diversity were, as hypothesised, higher in the milk d...

almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The other groups, including the 'Nilo-Saharan language speaking' milk-drinkers, show lower frequencies of LP and lower diversity, and there was a northeast to southwest decline in overall diversity. Amongst the Afro-Asiatic (Cushitic) language speaking Oromo, however, the geographic cline was not evident and the southern pastoralist Borana showed much higher LP frequency and enhancer diversity than the other groups. Together these results reflect the effects of parallel selection , the stochastic processes of the occurrence and spread of the mutations, and time depth of milk drinking tradition.

almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The other groups, including the 'Nilo-Saharan language speaking' milk-drinkers, show lower frequencies of LP and lower diversity, and there was a northeast to southwest decline in overall diversity. Amongst the Afro-Asiatic (Cushitic) language speaking Oromo, however, the geographic cline was not evident and the southern pastoralist Borana showed much higher LP frequency and enhancer diversity than the other groups. Together these results reflect the effects of parallel selection , the stochastic processes of the occurrence and spread of the mutations, and time depth of milk drinking tradition.

homozygosity (EHH) of the sequence surrounding the SNP of interest. We report here new data on the frequencies of the known LP alleles in the 'Old World' and their haplotype lineages. We examine and confirm EHH of each of the LP alleles in relation to their distinct lineages, but also show marked EHH for one of the older haplotypes that does not carry any of the five LP alleles. The region of EHH of this (B) haplotype exactly coincides with a region of suppressed recombination that is detectable in families as well as in population data, and the results show how such suppression may have exaggerated haplotype-based measures of past selection.