Eva E. Álvarez-León

Complex organochlorine pesticide mixtures as determinant factor for breast cancer risk: a population-based case-control study in the Canary Islands (Spain).

BackgroundAll the relevant risk factors contributing to breast cancer etiology are not fully known. Exposure to organochlorine pesticides has been linked to an increased incidence of the disease, although not all data have been consistent. Most published studies evaluated the exposure to organochlorines individually, ignoring the potential effects exerted by the mixtures of chemicals.MethodsThis population-based study was designed to evaluate the profile of mixtures of organochlorines detected in 103 healthy women and 121 women diagnosed with breast cancer from Gran Canaria Island, and the relation between the exposure to these compounds and breast cancer risk.ResultsThe most prevalent mixture of organochlorines among healthy women was the combination of lindane and endrin, and this mixture was not detected in any affected women. Breast cancer patients presented more frequently a combination of aldrin, dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD), and this mixture was not found in any healthy woman. After adjusting for covariables, the risk of breast cancer was moderately associated with DDD (OR = 1.008, confidence interval 95% 1.001-1.015, p = 0.024).ConclusionsThis study indicates that healthy women show a very different profile of organochlorine pesticide mixtures than breast cancer patients, suggesting that organochlorine pesticide mixtures could play a relevant role in breast cancer risk.

Polychlorobiphenyls and organochlorine pesticides in conventional and organic brands of milk: Occurrence and dietary intake in the population of the Canary Islands (Spain)

The population of the Spanish archipelago of the Canary Islands has been studied in depth regarding its levels of contamination by organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs). Foodstuffs of animal origin, such as milk, are prominent contributors to the body burden of these contaminants. As this population presents one of the highest milk-intake in Spain and Europe, we evaluated the level of OCs and PCBs in 26 commercially available brands of milk (16 conventional and 10 organic brands) present in the market of these Islands, in order to estimate the relevance of milk as a source of these chemicals for the Canary population. Our findings showed that hexachlorobenzene, trans-chlordane, and PCB153 were present in almost all the samples with independence of the type of milk. For both types of milks, the concentration of OCs was very low, showing organic milks lower levels than conventional ones. As a consequence, the estimated daily intake for OCs was lower than the tolerable daily intake (TDI) established by International Agencies. The levels of PCBs in milk were also found to be very low, but, in this case, the situation was the opposite: there were higher levels of PCBs in organic than in conventional brands of milk. Unexpectedly, levels of dioxin-like PCBs (DL-PCBs) reached values higher than 25 pg WHO-TEQ g(-1) fat in percentile 75 for both types of milk indicating the existence of a number of brands of milk highly contaminated by these toxicants. Consequently, the population who consume the most contaminated milk brands could have estimated daily intakes well above the recommended TDI (2 pg WHO-TEQ kg(-1)b.w.d(-1)) established by European Union Authorities. These results are of concern if we consider the well known adverse health effects exerted by dioxin-like compounds.

Background levels of polychlorinated biphenyls in the population of the Canary Islands (Spain)

Polychlorinated biphenyls (PCBs) are persistent and toxic compounds that have been detected in human serum or tissues worldwide. The objective of our study was to determine serum PCB levels in a representative sample of the general population of the Spanish Archipelago of the Canary Islands (607 serum samples from subjects aged between 6 and 75 years) in order to establish the main causes of this contamination and to evaluate the potential risks posed by these chemicals on the population through the use of toxicity equivalence to dioxins (TEQs). PCB congeners (28, 52, 77, 81, 101, 105, 114, 118, 123, 126, 138, 153, 156, 157, 167, 169, 180, and 189) were measured by gas chromatography-mass spectrometry (GC/MS). Our results showed that PCB residues were found in 76% of serum samples analyzed, with the congeners 153 and 180 being the most frequently detected and having the highest median values (21.8 and 6.7 ng/g lipid, respectively). Serum levels of non-dioxin-like PCBs increased with age, body mass index (BMI), urban habitat, and smoking. The median concentration of the sum of PCBs considered as markers of environmental contamination by these chemicals (M-PCBs) was 46.4 ng/g lipid. Levels of the sum of dioxin-like PCBs (DL-PCBs) were 48.5 ng/g lipid in the 95th percentile, and were also positively associated with age. As a consequence, age seemed to be positively associated with TEQs levels, reaching values as high as 58.6 pg/g lipid in the serum samples from oldest people. Our results indicate that the inhabitants of the Canary Archipelago show levels of PCB contamination lower than other populations present on the Spanish mainland, as well as many populations from developed countries. Nevertheless, as these compounds may induce adverse health effects even at very low doses, our findings should be considered by local Public Health authorities in order to establish measures for diminishing the exposure of the population of these islands to PCBs.

Consumption of foods of animal origin as determinant of contamination by organochlorine pesticides and polychlorobiphenyls: Results from a population-based study in Spain

The level of contamination with persistent organic pollutants (POPs) and dietary habits and food consumption was extensively studied in the population from the Canary Islands (Spain). Because foodstuffs of animal origin are well known to be prominent contributors to these contaminants, the current study aimed to assess the role of the dietary intake of animal products as a probability factor for increased serum POPs. The intake of animal products (dietary variables) as a determining factor for serum POP levels was investigated using multivariate statistical models. Our results showed that while poultry, rabbit, and cheese consumption increases the probability of having high levels of non-DDT-derivative pesticides, sausage, yogurt, lard, and bacon consumption decreases the probability of having high levels of these pesticides. In addition, poultry, rabbit, eggs, cream, and butter consumption increased the probability of having detectable levels of marker PCB, while dairy desserts decreased the probability of having detectable levels of these PCBs. On the contrary, sausage and meat consumption increased the probability of having detectable levels of dioxin-like PCBs (DL-PCBs). The current results confirm that dietary intake of foodstuffs of animal origin is a relevant risk factor for the accumulation of POPs (and therefore their serum levels). Our study indicates that the analysis of dietary patterns may be useful for identifying those individuals that will probably present a high body burden of POPs. Because POPs can exert deleterious effects on human health, the identification of populations at risk of being highly contaminated is mandatory in order to implement policies that minimize the exposure to these compounds.

Association of the European Lactase Persistence Variant (LCT-13910 C>T Polymorphism) with Obesity in the Canary Islands

Background European lactose tolerance genotype (LCT -13910 C>T, rs4988234) has been positively associated to body mass indexes (BMI) in a meta-analysis of 31,720 individuals of northern and central European descent. A strong association of lactase persistence (LP) with BMI and obesity has also been traced in a Spanish Mediterranean population. The aim of this study was to analyze a potential association of LP compared to lactase non-persistence (LNP) with BMI in inhabitants of the Canary Islands of Spain using Mendelian randomization. Methods A representative, randomly sampled population of adults belonging to the Canary Islands Nutrition Survey (ENCA) in Spain, aged 18–75 years (n = 551), was genotyped for the LCT – 13910 C>T polymorphism. Milk consumption was assessed by a validated questionnaire. Anthropometric variables were directly measured. WHO classification of BMI was used. Results LP individuals were significantly more obese than LNP subjects (χ2 = 10.59; p<0.005). LP showed in a multivariate linear regression analysis showed a positive association of LP with BMI compared to LNP, (β = 0.96; 95% CI: 0.08–1.85, p = 0.033). In a multinomial logistic regression analysis normal range weight LP subjects showed an odds ratio for obesity of 2.41; 95%CI 1.39–418, (p = 0.002) compared to LNP. Conclusions The T-13910 of the allele LCT-13910 C>T polymorphism is positively associated with BMI. LP increases significantly the risk to develop obesity in the studied population. The LCT-13910 C>T polymorphism stands proxy for the lifetime exposure pattern, milk intake, that may increase susceptibility to obesity and to obesity related pathologies.

Exposure to polycyclic aromatic hydrocarbons (PAHs) and bladder cancer: evaluation from a gene-environment perspective in a hospital-based case-control study in the Canary Islands (Spain)

Abstract Background: Exposure to polycyclic aromatic hydrocarbons (PAHs) has been linked to bladder cancer. Objective: To evaluate the role of PAHs in bladder cancer, PAHs serum levels were measured in patients and controls from a case-control study. Methods: A total of 140 bladder cancer patients and 206 healthy controls were included in the study. Sixteen PAHs were analyzed from the serum of subjects by gas chromatography–mass spectrometry. Results: Serum PAHs did not appear to be related to bladder cancer risk, although the profile of contamination by PAHs was different between patients and controls: pyrene (Pyr) was solely detected in controls and chrysene (Chry) was exclusively detected in the cases. Phenanthrene (Phe) serum levels were inversely associated with bladder cancer (OR = 0·79, 95%CI = 0·64–0·99, P = 0·030), although this effect disappeared when the allelic distribution of glutathione-S-transferase polymorphisms of the population was introduced into the model (multinomial logistic regression test, P = 0·933). Smoking (OR = 3·62, 95%CI = 1·93–6·79, P<0·0001) and coffee consumption (OR = 1·73, 95%CI = 1·04–2·86, P = 0·033) were relevant risk factors for bladder cancer. Conclusions: Specific PAH mixtures may play a relevant role in bladder cancer, although such effect seems to be highly modulated by polymorphisms in genes encoding xenobiotic-metabolizing enzymes.

Polymorphisms of glutathione S-transferase μ and θ, MDR1 and VEGF genes as risk factors of bladder cancer: A case-control study

OBJECTIVE The present study was aimed at examining the local distribution of GSTM1, GSTT1, MDR1, and VEGF gene polymorphisms as possible risk factors contributing to the development of bladder cancer among the population from Canary Islands, Spain. MATERIALS AND METHODS The genotypes were determined by PCR-based methods in a hospital-based case-control study consisting of 119 cases and 110 controls. The socio-demographic and clinicopathologic data were collected, including the smoking habits of the population covered in the study. RESULTS The observed allelic frequencies were (%): GSTM1-GSTT1, (positive) 54 and (null) 46 in cases, and 65 and 35, respectively, in controls (P = 0.144); MDR1 C3435T, (C) 57 and (T) 43 in cases, and 54 and 46, respectively, in controls (P = 0.633); VEGF A2578C, (A) 40 and (C) 60 in cases, and 51 and 49, respectively, in controls (P = 0.221). Among Canary Islands subjects, GSTT1-null genotype appeared as a significant risk factor for bladder cancer (odds ratio (OR) 2.0; 95% confidence interval (CI), 1.0-3.7; P = 0.041), in multivariate analysis adjusted by age and smoking habits. No statistical changes in genotype distribution of GSTM1, MDR1 C3435T, and VEGF A2578C gene polymorphisms were observed between cases and controls. The distribution of the initial clinical stage, clinical grade, or recurrence status was not significantly different among the polymorphic variants in the case group (P = NS). CONCLUSIONS Subjects with the GSTT1-null genotype might be at an increased risk of bladder cancer in Canary Islands, Spain. However, extensive studies are required for accurate confirmation of these results.

The relationship between dioxin-like polychlorobiphenyls and IGF-I serum levels in healthy adults: evidence from a cross-sectional study.

Objective Insulin-like growth factor I (IGF-I) and dioxin-like polychlorobiphenyls (DL-PCBs) have been associated with the pathogenesis of several diseases like cancer, diabetes and growth disorders. Because it has been suggested that organohalogenated contaminants could influence IGF-I levels in adults, the potential relationship between DL-PCBs and IGF-I serum levels was studied in 456 healthy adults from a representative sample of the general population of the Canary Islands (Spain). Design Free circulating serum levels of IGF-I and IGFBP-3 were measured through an ELISA methodology, while the serum levels of the 12 DL-PCBs congeners (IUPAC numbers # 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, and 189) were measured by gas chromatography/mass spectrometry (GC-MS). Results DL-PCBs 156 and 167, Total DL-PCBs body burden (∑PCBs: sum over the 12 measured DL-PCBs), and Total toxic burden (in terms of toxic equivalence to dioxins: ∑TEQs) showed a trend of inverse association with IGF-I serum levels in the whole studied population. After adjusting for potential confounders, including gender, body mass index (BMI), age, and IGF-binding protein-3 (IGFBP-3), younger (18–45 years) women with lower BMI (<27 kg/m2) and detectable levels of DL-PCB-156 showed significantly lower IGF-I levels than those in the same age and BMI subgroup with non-detectable levels of DL-PCB-156 (p<0.001). Similarly, ∑PCBs and ∑TEQs showed a tendency to an inverse association with IGF-I levels in the same group of women (p=0.017 and p=0.019 respectively). Conclusions These findings suggest that DL-PCBs could be involved in the regulation of the IGF-system in a way possibly influenced by gender, age and BMI. Although these results should be interpreted with caution, such circumstances could contribute to explain the development of diseases associated to the IGF system.