Low Vitamin D Levels and Frailty Status in Older Adults: A Systematic Review and Meta-Analysis.

Serum vitamin D deficiency is widespread among older adults and is a potential modifiable risk factor for frailty. Moreover, frailty has been suggested as an intermediate step in the association between low levels of vitamin D and mortality. Hence, we conducted a systematic review of the literature and meta-analysis to test the possible association of low concentrations of serum 25-hydroxyvitamin D (25(OH)D), a marker of vitamin D status, with frailty in later life. We reviewed cross-sectional or longitudinal studies evaluating populations of older adults and identifying frailty by a currently validated scale. Meta-analyses were restricted to cross-sectional data from studies using Fried's phenotype to identify frailty. Twenty-six studies were considered in the qualitative synthesis, and thirteen studies were included in the meta-analyses. Quantitative analyses showed significant differences in the comparisons of frail (standardized mean difference (SMD)-1.31, 95% confidence interval (CI) (-2.47, -0.15), p = 0.0271) and pre-frail (SMD-0.79, 95% CI (-1.58, -0.003), p = 0.0491) subjects vs. non-frail subjects. Sensitivity analyses reduced heterogeneity, resulting in a smaller but still highly significant between-groups difference. Results obtained indicate that lower 25(OH)D levels are significantly associated with increasing frailty severity. Future challenges include interventional studies testing the possible benefits of vitamin D supplementation in older adults to prevent/palliate frailty and its associated outcomes.

Effects of exposure to oil spills on human health: Updated review.

Oil spills may involve health risks for people participating in the cleanup operations and coastal inhabitants, given the toxicological properties of the oil components. In spite of this, only after a few major oil spills (crude oil or fuel oil no. 6) have studies on effects of exposure to diverse aspects of human health been performed. Previously, Aguilera et al. (2010) examined all documents published to that date dealing with any type of human health outcome in populations exposed to oil spills. The aim of the present review was to compile all new information available and determine whether evidence reported supports the existence of an association between exposure and adverse human health risks. Studies were classified in three groups according to type of health outcome addressed: (i) effects on mental health, (ii) physical/physiological effects, and (iii) genotoxic, immunotoxic, and endocrine toxicity. New studies published on oil-spill-exposed populations-coastal residents in the vicinity of the spills or participants in cleanup operations-provide additional support to previous evidence on adverse health effects related to exposure regarding different parameters in all three categories considered. Some of the observed effects even indicated that several symptoms may persist for some years after exposure. Hence, (1) health protection in these individuals should be a matter of concern; and (2) health risk assessment needs to be carried out not only at the time of exposure but also for prolong periods following exposure, to enable early detection of any potential exposure-related harmful effects.

Metal(loid) levels in biological matrices from human populations exposed to mining contamination--Panasqueira Mine (Portugal).

Mining activities may affect the health of miners and communities living near mining sites, and these health effects may persist even when the mine is abandoned. During mining processes various toxic wastes are produced and released into the surrounding environment, resulting in contamination of air, drinking water, rivers, plants, and soils. In a geochemical sampling campaign undertaken in the Panasqueira Mine area of central Portugal, an anomalous distribution of several metals and arsenic (As) was identified in various environmental media. Several potentially harmful elements, including As, cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se), were quantified in blood, urine, hair, and nails (toe and finger) from a group of individuals living near the Panasqueira Mine who were environmentally and occupationally exposed. A group with similar demographic characteristics without known exposure to mining activities was also compared. Genotoxicity was evaluated by means of T-cell receptor (TCR) mutation assay, and percentages of different lymphocyte subsets were selected as immunotoxicity biomarkers. Inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis showed elevated levels of As, Cd, Cr, Mn, and Pb in all biological samples taken from populations living close to the mine compared to controls. Genotoxic and immunotoxic differences were also observed. The results provide evidence of an elevated potential risk to the health of populations, with environmental and occupational exposures resulting from mining activities. Further, the results emphasize the need to implement preventive measures, remediation, and rehabilitation plans for the region.

Monitoring follow up of two areas affected by the Prestige oil four years after the spillage.

The sinking of the oil tanker Prestige in November 2002 resulted in the spill of more than 63,000 tonnes of crude oil, and polluted more than 1,000 km of coastline, especially affecting Galicia (northwestern Spain). Four years after the accident, a new biological monitoring study was undertaken of two Galician areas intensely affected by the spill, Lira and Ancoradoiro, previously evaluated in the months following the accident ( Laffon et al. 2006 ). The mussel Mytilus galloprovincialis was employed as bioindicator organism to determine both polycyclic aromatic hydrocarbons (PAH) levels and genotoxic effects. PAH were determined chromatographically in seawater samples and mussel tissues collected from November 2006 to January 2008. The results obtained showed that PAH pollution was still present in these areas, but bioaccumulation of these compounds in mussels was low, compared to reference mussels, and lower than in our previous study. DNA damage assessment was also performed in gills and hemolymph cells by means of the alkaline comet assay. DNA damage levels were higher in mussels from the exposed areas than in reference mussels. DNA damage decreased after a 7-d recovery period in the laboratory, but prolonging the recovery period up to 14 d did not contribute to less DNA damage in gill cells. Hemolymph cells were more sensitive than gill cells to the induction of DNA damage.

Review on the effects of exposure to spilled oils on human health.

Harmful effects of oil spills on diverse flora and fauna species have been extensively studied. Nevertheless, only a few studies have been compiled in the literature dealing with the repercussions of oil exposure on human health; most of them have focused on acute effects and psychological symptoms. The objective of this work was to gather all these studies and to analyze the possible consequences of this kind of complex exposure in the different aspects of human health. Studies found on this topic were related to the disasters of the Exxon Valdez, Braer, Sea Empress, Nakhodka, Erika, Prestige and Tasman Spirit oil tankers. The majority of them were cross-sectional; many did not include control groups. Acute effects were evaluated taking into account vegetative-nervous symptoms, skin and mucous irritations, and also psychological effects. Genotoxic damage and endocrine alterations were assessed only in individuals exposed to oil from Prestige. The results of the reviewed articles clearly support the need for biomonitoring human populations exposed to spilled oils, especially those individuals involved in the cleanup, in order to evaluate not only the possible immediate consequences for their health but also the medium- and long-term effects, and the effectiveness of the protective devices used.

The organic selenium compound selenomethionine modulates bleomycin-induced DNA damage and repair in human leukocytes.

The objective of this work was to evaluate the effects of selenomethionine (SeMet) on the induction, repair, and persistence of DNA damage in human leukocytes challenged with bleomycin (BLM). Comet assay was used to determine DNA strand breaks and hOGG1 for the specific recognition of oxidative damage. Leukocytes were (A) stimulated with phytohemagglutinin, (B) damaged with BLM, and (C) incubated to allow DNA repair. Comet assay was performed after each phase. SeMet (50 microM) was supplemented either during phase A, B, or C, or AB, or ABC. Treatment with SeMet decreased BLM-induced stand breaks when added during phase AB. Results obtained after the repair period indicate that SeMet favors repair of DNA damage especially when applied during phase AB. The comparison between DNA damage before and after repair showed that BLM-induced damage was repaired better in the presence of SeMet. Our results showed antigenotoxic effect of SeMet on BLM-induced DNA and also on repair and persistence of this damage when applied before and simultaneously with BLM.

In vitro evaluation of selenium genotoxic, cytotoxic, and protective effects: a review.

Selenium is an oligoelement with essential biological functions. Diet is the most important selenium source, and intake of this element depends on its concentration in food and amount of food consumed. Among the essential human micronutrients, selenium is peculiar due to its beneficial physiological activity and toxicity. It may have anticarcinogenic effects at low concentrations, whereas at concentrations higher than those necessary for nutrition, it can be genotoxic and carcinogenic. Because of that, selenium is probably the most widely investigated of all the oligonutrients. In the last decades, there has been increasing interest in several nutritional Se compounds because of their environmental, biological, and toxicological properties, particularly for their cancer- and disease-preventing activities. This article gives an overview of the results of in vitro studies on mutagenicity, genotoxicity, cytotoxicity, and DNA repair conducted within the last decades with different organic and inorganic selenium compounds. Results from these studies provide a better knowledge on the selenium activity and help to elucidate the reasons underlying its duality in order to regulate its correct use in nutrition and clinic.

Cytogenetic effects induced by Prestige oil on human populations: the role of polymorphisms in genes involved in metabolism and DNA repair.

The spill from the oil tanker Prestige (NW Spain, November 2002) was perhaps the biggest ecological disaster that happened worldwide in the last decades. As a consequence of this catastrophe a general concern led to a huge mobilization of human and technical resources. Given that no information was reported in the scientific literature regarding to the chronic repercussions to human health of exposure to oil spills, a pilot study was performed by our group revealing some increased genotoxic effects in the subjects exposed to the oil during cleaning activities. Due to the seriousness of the results, we extended our study comprising a larger population and including an extensive evaluation of the main polymorphic sites in metabolizing and DNA-repair genes. General increases in micronucleus (MN) frequency and decreases in the proliferation index were observed in individuals with longer time of exposure. Age was a significant predictor of MN frequency. CYP1A1 3'-UTR, EPHX1 codons 113 and 139, GSTP1, GSTM1 and GSTT1 metabolic polymorphisms, and XRCC3 codon 241 and XPD codon 751 repair polymorphisms influenced cytogenetic damage levels. In view of these results, it seems essential to pay more attention to the chronic human health effects of exposure to oil and to focus new studies on such a relevant but overlooked public health field that involves a large number of people all over the world.

Relationship between blood concentrations of heavy metals and cytogenetic and endocrine parameters among subjects involved in cleaning coastal areas affected by the 'Prestige' tanker oil spill.

The sinking of the 'Prestige' oil tanker in front of the Galician coast (NW of Spain) in November 2002 offered a unique opportunity to analyze intermediate cytogenetic and endocrine effects among people exposed to the complex mixture of substances that oil constitutes, including several toxic heavy metals. In this work we evaluated the relationship between exposure to heavy metals (blood concentrations of aluminium, cadmium, nickel, lead and zinc) and genotoxic parameters (sister chromatid exchanges, micronucleus test and comet assay) or endocrine parameters (plasmatic concentrations of prolactin and cortisol) in subjects exposed to 'Prestige' oil during cleaning tasks developed after the spillage. Concentrations of lead were significantly related to the comet assay even after adjusting by age, sex and smoking. Cortisol concentrations were significantly influenced by aluminium, nickel (both, inversely) and cadmium (positively). Women had clearly higher concentrations of prolactin and cortisol, even when adjusting by age, smoking, cadmium, aluminium or nickel. Plasmatic cortisol was jointly influenced by gender, smoking and aluminium or nickel (all p<0.05). In women there was a strong relationship between concentrations of cadmium and prolactin (beta=0.37, p=0.031). When the effects of cadmium, aluminium and nickel on cortisol were simultaneously assessed, only the latter two metals remained statistically significant. Among parameters analysed, cortisol appeared to be the most sensitive to the effects of metal exposure. Plasma levels of cortisol deserve further evaluation as a potentially relevant biomarker to assess the effects of exposure to heavy metals.

Initial study on the effects of Prestige oil on human health.

The big oil tanker Prestige wrecked at 130 miles from the coast of Galicia, on the Northwest of Spain, in November 19, 2002. During the accident over 40,000 tons of oil were spilled, and along the next weeks 22,000 more reached the shore in the way of three black tides. A great number of people participated in the cleaning tasks. The objective of this study was to initially evaluate the damage caused by Prestige oil in exposed individuals both from the cytogenetic and the endocrine points of view. Exposure level was determined by analysing volatile organic compounds in the environment and heavy metals in blood. Cytogenetic damage was determined by sister chromatid exchanges (SCE), and plasmatic prolactin and cortisol levels were used as biomarkers of endocrine toxicity. Finally we have determined the possible influence of GST genetic polymorphisms (GSTM1 and GSTT1 deletion polymorphisms, GSTP1 Ala105Val) on the evaluated effects. The exposed population was classified according to the performed cleaning tasks in three groups: volunteers that collaborated for 1 week (N=25), hired manual workers (N=20) and hired high-pressure cleaner workers (N=23). The control population consisted of 42 individuals. Exposure to Prestige oil caused cytogenetic damage in exposed individuals, being its effect influenced by age, sex, tobacco consumption and GSTM1 polymorphism. With regard to endocrine toxicity, our results showed that xenobiotics present in Prestige oil induced alterations in hormonal status, and thus it may be considered as an endocrine disruptor. Therefore, the selected parameters have shown to be good indicators of toxicity related to exposure to Prestige oil. In addition, data obtained point to the importance of using protective devices in preventing the effects related to the exposure.

Genetic damage induced by accidental environmental pollutants.

Petroleum is one of the main energy sources worldwide. Its transport is performed by big tankers following some established marine routes. In the last 50 years a total amount of 37 oil tankers have given rise to great spills in different parts of the world, Prestige being the last one. After the accident, a big human mobilisation took place in order to clean beaches, rocks and fauna, trying to reduce the environmental consequences of this serious catastrophe. These people were exposed to the complex mixture of compounds contained in the oil. This study aimed at determine the level of environmental exposure to volatile organic compounds (VOC), and the possible damage induced on the population involved in the different cleaning tasks by applying the genotoxicity tests sister chromatid exchanges (SCE), micronucleus (MN) test, and comet assay. Four groups of individuals were included: volunteers (V), hired manual workers (MW), hired high-pressure cleaner workers (HPW) and controls. The higher VOC levels were associated with V environment, followed by MW and lastly by HPW, probably due to the use of high-pressure cleaners. Oil exposure during the cleaning tasks has caused an increase in the genotoxic damage in individuals, the comet assay being the most sensitive biomarker to detect it. Sex, age and tobacco consumption have shown to influence the level of genetic damage, while the effect of using protective devices was less noticeable than expected, perhaps because the kind used was not the most adequate.

Genotoxicity associated to exposure to Prestige oil during autopsies and cleaning of oil-contaminated birds.

After the accident involving the oil tanker Prestige in November 2002 near 63,000 tons of heavy oil reached Galician coast (Northwest of Spain). This unleashed a large movement of volunteers to collaborate in several cleaning tasks. The aim of this study was to determine whether handling of Prestige oil-contaminated birds during autopsies and cleaning may have resulted in genotoxic damage. We have also evaluated the possible influence of DNA repair genetic polymorphisms (XRCC1 codons 194 and 399, XRCC3 codon 241 and APE1 codon 148) on susceptibility to the genotoxic effects evaluated. Exposure levels were analysed by determining volatile organic compounds in air samples. Peripheral blood samples were obtained from 34 exposed and 35 controls, and comet assay and micronucleus (MN) test were carried out. Genotyping was performed following PCR-RFLP procedures. Results obtained have shown significantly higher DNA damage, but not cytogenetic damage, in exposed individuals than in controls, related to time of exposure. Among exposed individuals, carriers of the variant alleles XRCC1 399Gln and APE1 148Glu have shown altered DNA damage with regard to wild-type homozygotes, suggesting exposure-genotype interactions. No effect of the DNA repair genetic polymorphisms analysed was observed in the MN test.

Evaluation of genotoxicity in a group of workers from a petroleum refinery aromatics plant.

Petroleum refinery workers are potentially exposed to a wide range of petroleum-derived hydrocarbons and chemical substances used in the manufacturing of petroleum derivatives. Benzene, toluene and xylene (BTX) are produced by distillation in the aromatics units and used as raw materials for petrol and petrochemical products. The aim of this study was to evaluate the genotoxic effects of occupational exposure to BTX in a petroleum refinery in the North of Portugal. The exposed group consisted of 48 workers from the aromatics plant and the control group consisted of 30 persons matched for various confounding factors. Chromosome aberrations (CA), micronuclei (MN), and DNA damage (evaluated by means of the comet assay) were measured in peripheral blood leukocytes. t,t-Muconic acid (t,t-MA), hippuric acid (HA) and methylhippuric acid (MHA) concentrations were measured in urine samples collected at the end of the workshift. The results suggest that occupational exposure to toluene and xylene is very low. A statistically significant increase in t,t-MA excretion was found in the exposed group although t,t-MA levels were found to be lower than the biological exposure index (BEI). Significant increases were found for CA, MN and comet tail length (TL) in the exposed group (p<0.05). No association was found between tobacco smoking and the effect biomarkers analysed. A positive association was found between CA and MN with age in the control group (p<0.05).

Monitoring of the impact of Prestige oil spill on Mytilus galloprovincialis from Galician coast.

In November 2002, the Prestige oil tanker was wrecked in front of Galician coast (NW of Spain), spilling near 63,000 tons of heavy oil until February 2003. Contamination produced was very extensive (70% of Galician beaches were reached by the oil) but heterogeneous, alternating intensely affected zones with neighbour locations where the repercussion was minimal. The objective of this study was to monitor sea environment contamination caused by Prestige oil spill during an 11-month period (August 2003-June 2004, nine samplings) in two locations of Galician coast with different geographical properties (Lira and Ancoradoiro beaches), by means of chemical determination of total polycyclic aromatic hydrocarbons (TPAH) in seawater, and using as exposure biomarker TPAH content in mussel (Mytilus galloprovincialis) tissues, and as effect biomarker DNA damage in mussel gills, evaluated by the comet assay. In addition, recovery ability of the mussels was determined after a 7-day stay in the laboratory. TPAH contents in seawater were very high in the earliest samplings, but then they maintained below 200 ng L(-)(1), similar to reference seawater. However, TPAH levels in mussel tissues were more variable: they increased again from January 2004, probably due to the adverse meteorological conditions that turned over the sea bottom and dispersed the oil accumulated in sediments. In most samplings, these levels decreased during the recovery stage. DNA damage in oil-exposed mussels was significantly higher than in reference mussels, both before and after the recovery phase, but they did not differ to one another. Comet tail length was slightly reduced during the recovery stage, indicative of a certain DNA repair in exposed mussels. This study showed up the importance of monitoring sea contamination events during an extended time, not only in evaluating the presence of the contaminants in the environment but also in determining their bioaccumulation and their effect on the exposed organisms.

Evaluation of PAH bioaccumulation and DNA damage in mussels (Mytilus galloprovincialis) exposed to spilled Prestige crude oil.

We analyzed the hydrocarbon composition of the Prestige oil as it reached the shores, its solubility in sea water, its bioaccumulation, and the genotoxic damage associated to oil exposure, using Mytilus galloprovincialis as sentinel organism. Mussels were exposed to two oil volumetric ratios (1:500 and 2:500) for 12 days. Great concentrations of total polycyclic aromatic hydrocarbons (TPAH) have been obtained, being in general higher in the samples from the dose of 1:500, both in sea water (55.14 vs. 41.96 microg/l) and mussel tissue (16,993.80 vs. 17,033.00 microg/kg), probably due to the great tendency of these compounds to link to particles in water. Comet assay results reflected an increase in the DNA damage associated to oil exposure, higher in the mussels exposed to the higher aqueous TPAH content. In the view of our results, the importance of the evaluation of biodisponibility, bioaccumulation and DNA damage in the assessment of the effects of xenobiotic pollutants to marine environments could be highlighted.