Maternal dietary intake of polyunsaturated fatty acids modifies association between prenatal DDT exposure and child neurodevelopment: A cohort study

BACKGROUND

Maternal 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) serum levels during pregnancy have been negatively linked to child neurodevelopment in contrast to intake of omega-3 and -6 (ω-3 and ω-6) fatty acids.

OBJECTIVES

To assess whether maternal dietary intake of ω-3 and ω-6 during pregnancy modifies the association between exposure to DDE and child neurodevelopment from age 42-60 months.

METHODS

Prospective cohort study with 142 mother-child pairs performed in Mexico. DDE serum levels were determined by electron capture gas chromatography. Dietary ω-3 and ω-6 intake was estimated by questionnaire. Child neurodevelopment was assessed by McCarthy Scales.

RESULTS

Docosahexaenoic (DHA) fatty acid intake significantly modified the association between DDE and motor component: increased maternal DDE was associated with lower motor development in children whose mothers had lower DHA intake (β_log2DDE = -1.25; 95% CI: -2.62, 0.12), in contrast to the non-significant increase among children whose mothers had higher DHA intake (β_{log2DDE-motor} = 0.50; 95% CI: 0.55, 1.56). Likewise, arachidonic fatty acid (ARA) intake modified the association between DDE and memory component: increased maternal DDE was associated with a significantly larger reduction in the memory component in children whose mothers had lower ARA intake (β_log2DDE = -1.31; 95% CI: -2.29, -0.32) than children whose mothers had higher ARA intake (β_{log2DDE-memory} = 0.17; 95% CI: -0.78, 1.11).

CONCLUSIONS

Dietary intake of DHA and ARA during pregnancy may protect against child neurodevelopment damage associated with prenatal maternal DDE levels.

Dietary flavonoids improve urinary arsenic elimination among Mexican women

Inorganic arsenic (iAs) exposure increases risk of several diseases, including cancer. Some nutrients such as flavonoids enhance glutathione activity, which in turn play a key role in iAs elimination. Our objective was to explore whether dietary non-soy flavonoids are associated with iAs metabolism. We hypothesized that the intake of flavonoids belonging to the following groups, flavan-3-ols, flavone, flavonol, flavanone, and anthocyanidin, is positively associated with urinary dimethylarsinic acid (DMA), which is the most soluble iAs metabolite excreted. We performed a cross-sectional study that included 1027 women living in an arsenic-contaminated area of northern Mexico. Flavonoid intake was estimated using a validated food frequency questionnaire. Concentration of urinary iAs and its metabolites (monomethylarsonic acid and DMA) were determined by high performance liquid chromatography ICP-MS. Results showed positive significant associations between DMA and the flavonoid groups flava-3-ols (β= 0.0112) and flavones (β= 0.0144), as well as the individual intake of apigenin (β= 0.0115), luteolin (β= 0.0138), and eriodictyol (β= 0.0026). Our findings suggest that certain non-soy flavonoids may improve iAs elimination; however, there is still very limited information available regarding the consumption of flavonoids and iAs metabolism.

Genetic susceptibility to breast cancer risk associated with inorganic arsenic exposure

OBJECTIVE

To evaluate whether the association between breast cancer (BC) and inorganic arsenic (iAs) exposure is modulated by selected polymorphisms in iAs metabolism.

METHODS

A population based case-control (1016/1028) study was conducted in Northern Mexico. Urinary arsenic metabolites were measured by High Performance Liquid Chromatography. Metabolites percentages and methylation ratios, were estimated. Genotypes of selected polymorphisms were determined by allelic discrimination. The interaction between polymorphisms and iAs metabolites percentages and methylation ratios on BC was assessed with unconditional logistic regression models.

RESULTS

A significant interaction (p=0.002) between MTR c.2756A>G polymorphism and percentage dimethylarsinic acid (DMA) on BC was found; BC risk related with %DMA was lower in AG+GG carriers than in AA carriers. No other significant interactions were found.

CONCLUSION

MTR c.2756A>G polymorphism may confer protection for BC associated with iAs exposure. Further research is warranted to elucidate the potential involvement of other polymorphisms in iAs-related BC.

Standards for arsenic in drinking water: Implications for policy in Mexico

Global concern about arsenic in drinking water and its link to numerous diseases make translation of evidence-based research into national policy a priority. Delays in establishing a maximum contaminant level (MCL) to preserve health have increased the burden of disease and caused substantial and avoidable loss of life. The current Mexican MCL for arsenic in drinking water is 25 μg/l (2.5 times higher than the World Health Organization (WHO) recommendation from 1993). Mexico's struggles to set its arsenic MCL offer a compelling example of shortcomings in environmental health policy. We explore factors that might facilitate policy change in Mexico: scientific evidence, risk communication and public access to information, economic and technological resources, and politics. To raise awareness of the health, societal, and economic implications of arsenic contamination of drinking water in Mexico, we suggest action steps for attaining environmental policy change and better protect population health.

Early motor development and cognitive abilities among Mexican preschoolers

Psychomotricity plays a very important role in children's development, especially for learning involving reading-writing and mathematical calculations. Evaluate motor development in children 3 years old and its relationship with their cognitive abilities at the age of 5 years. Based on a cohort study, we analyzed the information about motor performance evaluated at 3 years old by Peabody Motor Scale and cognitive abilities at 5 years old. The association was estimated using linear regression models adjusted by mother's intelligence quotient, sex, Bayley mental development index at 18 months, and quality of the environment at home (HOME scale). 148 children whose motor performance was determined at age 3 and was evaluated later at age 5 to determine their cognitive abilities. Cognitive abilities (verbal, quantitative, and memory) measured by McCarthy Scales. Significant positive associations were observed between stationary balance at age 3 with verbal abilities (β = 0.67, p = .04) and memory (β = 0.81, p = .02) at 5 years. Grasping and visual-motor integration were significant and positively associated with quantitative abilities (β = 0.74, p = .005; β = 0.61, p = .01) and memory (β = 2.11, p = .001; β = 1.74, p = .004). The results suggest that early motor performance contributes to the establishment of cognitive abilities at 5 years. Evaluation and early motor stimulation before the child is faced with formal learning likely helps to create neuronal networks that facilitate the acquisition of academic knowledge.

Arsenic metabolism and cancer risk: A meta-analysis

OBJECTIVE

To describe the studies that have reported association measures between risk of cancer and the percentage distribution of urinary inorganic arsenic (iAs) metabolites by anatomical site, in non-ecological epidemiological studies.

METHODS

Studies were identified in the PubMed database in the period from 1990 to 2015. Inclusion criteria were: non-ecological epidemiological study, with histologically confirmed cancer cases, reporting the percentage distribution of inorganic arsenic (iAs), monomethylated (MMA) and dimethylated (DMA) metabolites, as well as association measures with confidence intervals (CI) between cancer and %iAs and/or %MMA and/or %DMA. A descriptive meta-analysis was performed by the method of the inverse of the variance for the fixed effects model and the DerSimonian and Laird's method for the random effects model. Heterogeneity was tested using the Q statistic and stratifying for epidemiological design and total As in urine. The possibility of publication bias was assessed through Begg's test.

RESULTS

A total of 13 eligible studies were found, most of them were performed in Taiwan and focused on skin and bladder cancer. The positive association between %MMA and various types of cancer was consistent, in contrast to the negative relationship between %DMA and cancer that was inconsistent. The summary risk of bladder (OR=1.79; 95% CI: 1.42, 2.26, n=4 studies) and lung (OR=2.44; 95% CI: 1.57, 3.80, n=2 studies) cancer increased significantly with increasing %MMA, without statistical heterogeneity. In contrast, lung cancer risk was inversely related to %DMA (OR=0.58; 95% CI: 0.36, 0.93, n=2 studies), also without significant heterogeneity. These results were similar after stratifying by epidemiological design and total As in urine. No evidence of publication bias was found.

CONCLUSION

These findings provide additional support that methylation needs to be taken into account when assessing the potential iAs carcinogenicity risk.

Abstract P5-08-11: Urinary arsenic metabolites and risk of breast cancer molecular subtypes in northern Mexican women

Background/Aim: For many years, the presence of arsenic (As) in drinking water of some areas in Northern Mexico has been a major concern. As levels have ranged from 71 to 600 μg/L. We have recently reported that women residing in Northern Mexico, with higher urinary monomethyl arsenic acid percentage (%MMA) had an increased breast cancer (BC) risk (MMA% ORQ5vs.Q1=2.63; 95%CI: 1.89, 3.66; p for trend <0.001) (López-Carrillo et al., 214).

Breast tumor subtypes with distinctive biology and treatment responses are defined by the immunohistochemical expression of estrogen and progesterone receptors (HR) and human epidermal growth factor receptor 2 (HER2). Epidemiological evidence suggests that BC risk factors (i.e. breastfeeding, parity, menarche, etc.) may vary by tumor pathology.We assessed if %MMA is associated with a particular BC molecular subtype.

Methods: A population based case–control study was performed from 2007 to 2011 in five states of Northern Mexico. Incident cases were identified from main public tertiary hospitals in the study area. A total of 499 patients with histopathologically confirmed BC and molecular subtype status available information were identified. Controls were healthy women, with no history of cancer, matched 1:1 by age.

Tumor marker information for estrogen receptor (ER), progesterone receptor (PR) and HER2 was obtained from medical records. ER+ and PR+ was based on >=1% cell staining. HER2+ status was determined when at least 30% of protein overexpression was observed in the tumor cell. Cases were assigned to one of three tumor marker categories: HR+ (ER+ and/or PR+ and HER2-), HER+ (regardless of ER or PR status) and TNBC (ER-, PR-, and HER2-).

Urinary concentrations (μg/L) of species As3+, As5+, MMA5+, DMA5+, and arsenobetaine (AsB) were determined by high-performance liquid chromatography ICP-MS. Detection limits were As3+: 0.12; As5+: 0.20; MMA5+: 0.12; DMA5+: 0.08; AsB: 0.08. Results were reported by g of creatinine. Total As was calculated by using both the sum of iAs, MMA, DMA plus or minus AsB concentration (TAs or TAs-AsB, respectively). iAs was calculated as the sum of trivalent (As3+) and pentavalent (As5+). %iAs, %MMA and %DMA species were estimated using TAs-AsB as denominator.

Using logistic regression models, the associations between BC molecular subtypes and MMA% and DMA% was estimated according to the observed quintile distribution among controls. Based on the median value of each quintile a lineal trend was assessed accordingly.

Results.The mean age of cases and controls was around 54 years with 51 years of residence in the study zone. In the entire population, TAs ranged from 0.47 to 303.29 μg/L (0.45 to 1683.83 μg/g creatinine). HR+ BC patients were 57%, HER2 23% and TNBC 20%. These figures are similar to those reported among other groups of Mexican cancer patients. After controlling by key BC factors, %MMA remained as a significant risk factor for BC only for HR+. HER2+ and TNBC tumors were not significantly associated with urinary As metabolites.

Conclusion: Our results suggest that increased BC risk related to As exposure is not mediated by HER2 expression. This is the first report on As exposure and breast cancer subtypes which requires further confirmation.

Citation Format: López-Carrillo L, Gamboa-Loira B, Cebrián ME. Urinary arsenic metabolites and risk of breast cancer molecular subtypes in northern Mexican women [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-08-11.

Phthalate exposure, flavonoid consumption and breast cancer risk among Mexican women

OBJECTIVE

To evaluate if selected phthalate exposure and flavonoid intake interact on breast cancer (BC) risk.

MATERIAL AND METHODS

Interviews and urine samples were obtained from 233 women with histologically confirmed BC and 221 healthy controls matched by age and place of residence, from various states of northern Mexico. Urinary metabolites concentrations of diethyl phthalate (DEP), butyl benzyl phthalate (BBzP) and dioctyl phthalate (DOP) were determined by solid-phase extraction coupled with high-performance liquid chromatography/isotope dilution/tandem mass spectrometry. Using a semiquantitative food frequency questionnaire, consumption of five types of flavonoids (anthocyanidins, flavan-3-ols, flavanones, flavones and flavonols) was estimated according to three food groups: vegetables, fruits and legumes-oil seeds.

RESULTS

A higher intake of anthocyanidins and flavan-3-ols (from vegetables), synergistically increased the negative association between BBzP and BC. No other significant flavonoid-phthalate multiplicative interactions on the risk for BC were found.

CONCLUSION

The consumption of some flavonoids may interact with exposure to phthalates on the risk of BC. Epidemiological and underlying mechanisms information is still insufficient and requires further investigations.

Dietary micronutrient intake and its relationship with arsenic metabolism in Mexican women

INTRODUCTION

Concentrations of inorganic arsenic (iAs) metabolites in urine present intra- and interindividual variations, which are determined not only by the magnitude of exposure to iAs, but also by differences in genetic, environmental and dietary factors.

OBJECTIVE

To evaluate whether differences in dietary intake of selected micronutrients are associated with the metabolism of iAs.

METHODS

The intake of 21 micronutrients was estimated for 1027 women living in northern Mexico using a food frequency questionnaire. Concentration of urinary metabolites of iAs was determined by high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and the proportion of iAs metabolites was calculated (%iAs, monomethylarsonic acid [%MMA] and dimethylarsinic acid [%DMA]), as well as ratios corresponding to the first (MMA/iAs), second (DMA/MMA) and total methylation (DMA/iAs).

RESULTS

After adjustment for covariates, it was found that methionine, choline, folate, vitamin B12, Zn, Se and vitamin C favor elimination of iAs mainly by decreasing the %MMA and/or increasing %DMA in urine.

CONCLUSIONS

Our results confirm that diet contributes to the efficiency of iAs elimination. Further studies are needed to assess the feasibility of dietary interventions that modulate the metabolism of iAs and the consequent risk of diseases related to its exposure.

Sex differences in the reduction of arsenic methylation capacity as a function of urinary total and inorganic arsenic in Mexican children

Chronic arsenic (As) exposure decreases adult and children's ability to methylate inorganic As (iAs); however, few studies have examined children's sex differences. We measured urinary concentrations of iAs, monomethylarsonic (MMA), and dimethylarsinic (DMA) acids, and calculated the primary (PMI: MMA/iAs) and secondary (SMI: DMA/MMA) methylation capacity indexes in 591 children 6-8 years in Torreón, Mexico. We determined iAs, MMA, and DMA by hydride generation cryotrapping AAS. Lineal regression models estimated associations between methylation capacity and total As (TAs) or iAs. Interactions with sex were tested at p<0.10. Boys had significantly higher TAs levels, (58.4µg/L) than girls (46.2µg/L). We observed negative associations between TAs and PMI (β=-0.039; p<0.18) and SMI (β=-0.08; p=0.002) with significant sex differences; PMI reduction was significant in boys (β=-0.09; p=0.02) but not in girls (β=0.021; p=0.63), p for interaction=0.06. In contrast, SMI reduction was significantly more pronounced in girls. Furthermore, negative associations PMI (β=-0.19; p<0.001) and SMI (β=-0.35; p<0.001) were a function of urinary iAs levels, independently of TAs; however, the reduction in PMI was more pronounced in boys (β=-0.24; p<0.001; girls β=-0.15; p<0.001), p for interaction=0.04. A significant negative association was observed between SMI and iAs levels without significant sex differences. TAs and iAs associations with metabolite percentages were in good agreement with those observed with methylation indexes. Our results suggest that iAs plays an important role in reducing As methylation ability and that significant sex differences are present in As metabolism. These differences merit further investigation to confirm our findings and their potential implications for arsenic toxicity in children.

Association between organochlorine pesticide exposure and thyroid hormones in floriculture workers

Several studies have suggested that exposure to DDT may be related to changes in thyroid hormone levels in animals and humans, even though results across studies are inconsistent. The aim of this study was to assess the association between exposure to p,p'-DDE (a stable metabolite of DDT) and serum levels of thyroid hormones in floriculture workers. A longitudinal study was conducted on 136 male subjects from the States of Mexico and Morelos, Mexico, who were occupationally exposed to pesticides, during agricultural periods of high (rainy season) and low (dry season) levels of pesticide application. Using a structured questionnaire, a survey was carried out on socio-demographic characteristics, anthropometry, clinical history, alcohol and tobacco consumption, residential chemical exposure, and occupational history. Blood and urine samples were collected to determine serum levels of TSH, total T3, total T4, and p,p'-DDE, and metabolites of organophosphate pesticides (OP), respectively. The analysis of the associations between p,p'-DDE levels and thyroid hormone profile adjusting by potential confounding variables including urinary OP metabolites was carried out using multivariate generalized estimating equation (GEE) models. Our results showed that the geometric means of p,p'-DDE levels were 6.17 ng/ml and 4.71 ng/ml in the rainy and dry seasons, respectively. We observed positive associations between the serum levels of p,p'-DDE and those of total T3 (β=0.01, 95% CI: -0.009, 0.03), and total T4 (β=0.08, 95% CI:0.03, 0.14) and negative but no significant changes in TSH in male floricultural workers, supporting the hypothesis that acts as thyroid disruptor in humans.

History of gonorrhea and prostate cancer in a population-based case-control study in Mexico

We evaluated the association between a history of sexually transmitted diseases (STDs) and the risk for prostate cancer (PC) among Mexican males.

METHODS

PC incident cases (n=402) that were identified at six public hospitals in Mexico City were matched by age (±5 years) with 805 population controls with no history of PC. By face-to-face interview, we obtained information about sexual history, previous STDs, sociodemographic characteristics, and familial history of PC. An unconditional logistic regression model was used to estimate the risk for PC.

RESULTS

A total of 16.6% of men reported having had at least one previous STD, and the most frequently reported STD was gonorrhea (10.5%). After adjusting by PC familial history, the history of STD was associated with a two-fold greater risk of PC: odds ratio (OR)=2.67; 95% confidence interval (95% CI=1.91-3.73). When each STD was evaluated separately, only gonorrhea was associated with a significant increase in PC risk (OR=3.04; 95% CI=1.99-4.64). These associations were similar when we stratified by low-risk PC (Gleason <7) and high-risk PC (Gleason ≥7).

CONCLUSION

These results confirm that STDs, and particularly gonorrhea, may play an etiological role in PC among Mexican males, which is consistent with a previous report from a multiethnic cohort.

Breast cancer age at diagnosis patterns in four Latin American Populations: A comparison with North American countries

BACKGROUND

In the Latin America countries (LAC), one in five breast cancer (BC) cases occur in women younger than 45 years, almost twice the frequency seen in developed countries. Most BC cases in younger women are premenopausal and are generally more difficult to detect at early stages and to treat than postmenopausal cancers. We employ data from four high quality population-based registries located in LAC and assess the extent to which the higher frequency of BC occurring in younger women is due to a younger population structure, compared to that of developed countries. Next, we analyze secular and generational trends of incidence rates in search for additional explanations.

METHODS

Using data from the International Agency for Research on cancer, between 1988 and 2007, the age distribution of BC incident cases for registries located in Brazil, Colombia, Costa Rica, Ecuador is compared to that of USA and Canadian registries, both before and after removing differences in population age structure. An age-period-cohort modelling of incidence rates is also conducted in all compared registries to identify secular and generational effects.

RESULTS

BC incident cases in the LAC registries present, on average, at an earlier age than in the USA and Canadian registries and for 2003-2007, between 20 and 27% of cases occur in women aged 20-44. About two thirds of the difference in age distribution between LAC and USA registries is attributable to the younger age distribution in the LAC base populations. The USA registries show the highest age-specific BC incidence rates of all compared aggregated registries, at all ages. However, in all the LAC registries incidence rates are rapidly increasing, fueled by a strong birth cohort effect. This cohort effect may be explained by important reduction in fertility rates occurring during the second half of the 20th century, but also by a greater exposure to other risk factors for BC related to the adoption of life styles more prevalent in developed countries.

CONCLUSION

The younger age at presentation of BC incident cases seen in the analyzed LAC registries, and possibly in many Latin American countries, is not only attributable to their relatively young population age structure but also to the low incidence rates in older women. As more recently born cohorts, with greater exposure to risk factors for postmenopausal BC, reach older age, incidence rates will be more similar to the rates seen in the USA and Canadian registries. There is a need for additional research to identify determinants of the higher BC rate among younger women in these countries.

Prenatal p,p'-DDE exposure and establishment of lateralization and spatial orientation in Mexican preschooler

BACKGROUND

Prenatal exposure to p,p'-DDE is associated with impairments in motor development during the first year of life, with no related repercussions on mental or motor development at 12-30 months and with impairments in cognitive areas, but not in perceptual and motor areas at preschool age. However, its association with particular psychomotor factors, such as establishment of lateralization and spatial orientation, essential elements to the overall learning and specifically reading, writing and spelling in preschoolers, has not been independently evaluated, since cognitive and motor areas have only been explored globally.

OBJECTIVE

To determine the association between prenatal exposure to p,p'-DDE and the establishment of lateralization and spatial orientation in children 5 years of age.

MATERIALS AND METHODS

Establishment of lateralization and spatial orientation was evaluated using the McCarthy Scale of Children's Abilities, with 167 children 5 years of age who participated in a birth cohort in the state of Morelos, Mexico. The information available for each child included: serum concentrations of p,p'-DDE of the mother during at least one trimester of pregnancy, mothers' intelligence quotients, stimulation at home and anthropometry. A logistic regression model was used to calculate the association between prenatal exposure to p,p'-DDE and lateralization and a multiple linear regression model was used for the association with spatial orientation.

RESULTS

A two-fold increase in p,p'-DDE in lipid base during the second trimester of pregnancy was associated with a significant reduction, -0.18 points (95% CI -0.41; 0.04, in the spatial orientation index, with no impairment in the establishment of hemispheric dominance. Attending preschool and the maternal intelligence quotient were the main determinants of spatial orientation and the establishment of hemispheric dominance.

CONCLUSIONS

Prenatal exposure to p,p'-DDE may affect the 5 year old's ability to identify spatial orientation of oneself and surrounding objects. Given the observed role of attending preschool in the functions studied, early attendance in formal education might serve as a stimulation strategy for preschoolers. These preliminary results should be verified and expanded in further prospective studies with DDE.

Dieta y cáncer gástrico en México y en el mundo

El cáncer gástrico (CG) es la cuarta causa de muerte por cáncer a nivel global. La dieta y el consumo de alcohol y tabaco, además de la infección por Helicobacter pylori determinan un gran número de casos de esta neoplasia. Algunos alimentos contienen sustancias que podrían influir en el proceso de carcinogénesis gástrica, aunque los mecanismos subyacentes no están completamente dilucidados. En México y el mundo, la disminución en el consumo de frutas, vegetales no feculentos y allium, leguminosas y alimentos fuente de selenio, así como el aumento en el consumo de sal, alimentos salados, salmuera y ahumados, chile, carnes procesadas y asadas o a la parrilla se han asociado respectivamente con un aumento de riesgo de CG. Con la evidencia disponible, se podrían desarrollar y evaluar programas para la prevención y control del CG.

Utilización correcta de las técnicas de detección de cáncer de mama en mujeres mexicanas

Objetivo. Identificar las características asociadas con la prevalencia de utilización correcta de la autoexploración manual (AE), el examen clínico (EC) y la mamografía (MA) para la detección de cáncer mamario (CaMa). Material y métodos. Se entrevistó a 1 030 mujeres mexicanas, sanas, de entre 20 y 88 años sobre su historia reproductiva y sociodemográfica. Con base en la forma y frecuencia de realización de estas técnicas de detección, se construyó un índice de utilización correcta. Resultados. La prevalencia de utilización correcta de la AE fue de 11% y del EC de 5.4%. El 7.6% de las mujeres entre 40 y 49 años y 31.6% de las mujeres con 50 años o más se realizaron una MA de acuerdo con la norma vigente al momento del estudio. El aseguramiento por parte del Instituto Mexicano del Seguro Social, del Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado o del Seguro Popular fue el principal determinante de la utilización de la MA. Conclusiones. Se evidencia la necesidad de incrementar la correcta utilización de la AE, el EC y la MA.

[Diet and gastric cancer in Mexico and in the world]

Gastric cancer (GC) is the fourth leading cause of cancer death at global level. Diet, alcohol and tobacco, in addition to Helicobacter pylori infection, account for a large number of cases. Some substances contained in foods may influence GC carcinogenesis process; however, the underlying mechanisms have not been fully elucidated. In Mexico and worldwide, a low intake of fruits, non-starchy and allium vegetables, pulses, and foods containing selenium, as well as high intake of salt, salty, salted and smoked foods, chili pepper, processed and grilled/barbecued meats, have been respectively associated with an increased risk of GC. Based on the available evidence, programs for GC prevention and control could be developed and evaluated.

[Correct utilization of breast cancer detection techniques in Mexican women]

OBJECTIVE

Identify the characteristics associated with correct utilization of self examination (SE), clinical exam (CE) and mammography (MA) for breast cancer (BC) early detection.

MATERIALS AND METHODS

Interviews were undertaken with 1 030 Mexican women (n=1 030), 20 to 88 years of age, regarding their reproductive and sociodemographic characteristics. An index of correct utilization was constructed based on the form and frequency practice of those techniques.

RESULTS

The prevalence of correct utilization of SE was 11% and 5.4% for CE. Further, 7.6% of women 40-49 years of age with 2 or more BC risk factors had MA during the two years prior to the interview, and for 31.6% among women ≥50 years of age the MA was annually. The main determinant of MA utilization was having financial protection from either IMSS, ISSSTE or Seguro Popular.

CONCLUSIONS

It is necessary to improve the correct utilization of BC detection techniques in Mexico.

Breast cancer in young women in Latin America: an unmet, growing burden

BACKGROUND

Breast cancer (BC) is the leading cause of malignancy-related deaths among women aged ≤ 45 years. There are unexplored and uncertain issues for BC in this particular group in Latin America. The aim of this study is to evaluate BC incidence and mortality among young women and related clinicopathological and survivorship aspects in this region.

MATERIALS AND METHODS

Data were obtained from Globocan 2008 and the International Agency for Research on Cancer's Cancer Incidence in Five Continents series plus databases. We requested collaboration from the 12 different national cancer institutes in Latin America through SLACOM, the Latin American and Caribbean Society of Medical Oncology, and conducted a systematic literature review to obtain local data regarding the prevalence of BC among young women and their characteristics, outcomes, and survivorship-related issues.

RESULTS

BC incidence and mortality proportions for Latin American women aged <44 years were higher when compared with those of developed countries (20% vs. 12% and 14% vs. 7%, respectively). We found only a few Latin American series addressing this topic, and prevalence varied between 8% and 14%. Stage II and III disease, high histological grade, and triple-negative and HER2 BC were features frequently observed among young Latin American BC patients.

CONCLUSION

The rising incidence and mortality of BC in young Latin American women is a call to action in the region. It is necessary to monitor the epidemiological and clinical data through reliable cancer registries and to consider the implementation of protocols for education of patients and health professionals. This unmet, growing burden must be considered as a top priority of the national programs in the fight against BC, and models of specialized units should be implemented for this particular group of patients to provide better care for this emergent challenge.

Arsenic methylation capacity is associated with breast cancer in northern Mexico

Exposure to environmental contaminants, dietary factors and lifestyles may explain worldwide different breast cancer (BC) incidence. Inorganic arsenic (iAs) in the drinking water is a concern in many regions, such as northern Mexico. Studies in several countries have associated the proportion of urinary monomethylarsenic (%MMA) with increased risks for many As-related diseases, including cancer. To investigate the potential relationships between the risk of BC and the capacity to methylate iAs, a hospital-based case-control study (1016 cases/1028 controls) was performed in northern Mexico. Women were directly interviewed about their reproductive histories. The profile of As metabolites in urine was determined by HPLC-ICP-MS and methylation capacity was assessed by metabolite percentages and indexes. Total urinary As, excluding arsenobetaine (TAs-AsB), ranged from 0.26 to 303.29μg/L. Most women (86%) had TAs-AsB levels below As biological exposure index (35μg/L). Women with higher %MMA and/or primary methylation index (PMI) had an increased BC risk (%MMA ORQ5vs.Q1=2.63; 95%CI 1.89,3.66; p for trend <0.001; PMI ORQ5vs.Q1=1.90; 95%CI 1.39,2.59, p for trend <0.001). In contrast, women with higher proportion of urinary dimethylarsenic (%DMA) and/or secondary methylation index (SMI) had a reduced BC risk (%DMA ORQ5vs.Q1=0.63; 95%CI 0.45,0.87, p for trend 0.006; SMI ORQ5vsQ1=0.42, 95%CI 0.31,0.59, p for trend <0.001). Neither %iAs nor total methylation index was associated to BC risk. Inter-individual variations in iAs metabolism may play a role in BC carcinogenesis. Women with higher capacity to methylate iAs to MMA and/or a lower capacity to further methylate MMA to DMA were at higher BC risk.

[Environmental health in Mexico: current situation and future prospects]

Environmental health has been established in Mexico as a discipline since the early nineties resuming the sanitarian tradition developed over the past century and incorporating new knowledge generated by environmental toxicology and epidemiology. During the last decade there has been some progress in reviewing and updating the regulations, designing programs and policies to reduce exposure to pollutants and consolidating research groups and teaching in the area. However, the most prevalent problems previously diagnosed still remain and new risks have emerged due to environmental degradation (air pollution, toxics exposure and climate change among others) have been incorporated. If this trend persists, the environmental risks will continue to increase and multiply. The environmental health governance in Mexico has to be redesigned involving a transectoral approach. Future proposals might include: establishment of a National Environmental Health Program, update the situational diagnosis at national and regional level, strengthening teaching and graduate programs in environmental health as well as increase support for research in the area and development of an integrated environmental health surveillance system.

Prenatal molybdenum exposure and infant neurodevelopment in Mexican children

OBJECTIVE

To evaluate the association between prenatal exposure to molybdenum (Mo) and infant neurodevelopment during the first 30 months of life.

METHODS

We selected a random sample of 147 children who participated in a prospective cohort study in four municipalities in the State of Morelos, Mexico. The children were the products of uncomplicated pregnancies with no perinatal asphyxia, with a weight of ≥2 kg at birth, and whose mothers had no history of chronic illnesses. These women were monitored before, during, and after the pregnancy. For each of these children a maternal urine sample was available for at least one trimester of pregnancy, and urine Mo levels were determined by electrothermal atomic absorption spectrometry. Neurodevelopment was evaluated using the psychomotor (PDI) and mental development indices (MDI) of the Bayley scale. Association between prenatal exposure to Mo and infant neurodevelopment was estimated using generalized mixed effect models.

RESULTS

The average urinary concentrations of Mo adjusted for creatinine varied between 45.6 and 54.0 µg/g of creatinine at first and third trimester, respectively. For each doubling increase of Mo (μg/g creatinine) during the third trimester of pregnancy, we observed a significant reduction on PDI (β = -0.57 points; P = 0.03), and no effect on MDI (β = 0.07 points; P = 0.66).

DISCUSSION

As this is the first study that suggests a potential negative association between prenatal Mo exposure and infant neurodevelopment, these results require further confirmation.

Breast cancer in young women in Latin America: an unmet, growing burden

Breast cancer (BC) is the leading cause of malignancy-related deaths among women aged ≤45 years. There are unexplored and uncertain issues for BC in this particular group in Latin America. The aim of this study is to evaluate BC incidence and mortality among young women and related clinicopathological and survivorship aspects in this region.

MATERIALS AND METHODS

Data were obtained from Globocan 2008 and the International Agency for Research on Cancer's Cancer Incidence in Five Continents series plus databases. We requested collaboration from the 12 different national cancer institutes in Latin America through SLACOM, the Latin American and Caribbean Society of Medical Oncology, and conducted a systematic literature review to obtain local data regarding the prevalence of BC among young women and their characteristics, outcomes, and survivorship-related issues.

RESULTS

BC incidence and mortality proportions for Latin American women aged <44 years were higher when compared with those of developed countries (20% vs. 12% and 14% vs. 7%, respectively). We found only a few Latin American series addressing this topic, and prevalence varied between 8% and 14%. Stage II and III disease, high histological grade, and triple-negative and HER2 BC were features frequently observed among young Latin American BC patients.

CONCLUSION

The rising incidence and mortality of BC in young Latin American women is a call to action in the region. It is necessary to monitor the epidemiological and clinical data through reliable cancer registries and to consider the implementation of protocols for education of patients and health professionals. This unmet, growing burden must be considered as a top priority of the national programs in the fight against BC, and models of specialized units should be implemented for this particular group of patients to provide better care for this emergent challenge.

La salud ambiental en México: situación actual y perspectivas futuras

La salud ambiental se establece en México como disciplina a principios de los noventa retomando la tradición sanitarista del siglo pasado e incorporando nuevo conocimiento generado por la epidemiología y la toxicología ambiental. Durante la última década se han presentado avances en la revisión y actualización de la normatividad, se han diseñado programas y políticas para reducir la exposición a contaminantes y se han consolidado grupos de investigación y docencia en el área. Sin embargo, la mayoría de los problemas previamente diagnosticados prevalecen y se han incorporados nuevos riesgos a la salud producto del deterioro ambiental (contaminación atmosférica, exposición a tóxicos, cambio climático). Resulta necesario replantear el modelo de gobernanza en salud  ambiental en México desde una perspectiva transectorial. Se propone crear un Programa Nacional de Salud Ambiental, actualizar el diagnóstico en el  ámbito nacional y regional, fortalecer la enseñanza e investigación así como desarrollar un sistema integrado de vigilancia en salud ambiental.

PPARγ and PPARGC1B polymorphisms modify the association between phthalate metabolites and breast cancer risk

CONTEXT

Breast cancer (BC) risk has been differentially associated with urinary levels of some phthalate metabolites.

OBJECTIVE

To investigate whether PPARγ and PPARGC1B polymorphisms modulate these associations.

MATERIALS AND METHODS

208 BC cases were age-matched with 220 population controls. Phthalate metabolites were determined by HPLC-MS. PPARγ Pro12Ala (rs1801281) and PPARGC1B Ala203Pro (rs7732671) and Val279Ile (rs17572019) were genotyped.

RESULTS

The association between mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and BC risk was positively modified in PPARγ Pro12Ala C carriers. The association with mono-iso-butyl phthalate (MiBP) in PPARGC1B Ala203Pro G carriers was negatively modified.

CONCLUSION

PPARγ and PPARGC1B polymorphisms modulate the association between phthalate exposure and BC risk.

Prenatal p,p´-DDE exposure and neurodevelopment among children 3.5-5 years of age

BACKGROUND

The results of previous studies suggest that prenatal exposure to bis[p-chlorophenyl]-1,1,1-trichloroethane (DDT) and to its main metabolite, 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), impairs psychomotor development during the first year of life. However, information about the persistence of this association at later ages is limited.

OBJECTIVES

We assessed the association of prenatal DDE exposure with child neurodevelopment at 42-60 months of age.

METHODS

Since 2001 we have been monitoring the neurodevelopment in children who were recruited at birth into a perinatal cohort exposed to DDT, in the state of Morelos, Mexico. We report McCarthy Scales of Children's Abilities for 203 children at 42, 48, 54, and 60 months of age. Maternal DDE serum levels were available for at least one trimester of pregnancy. The Home Observation for Measurement of the Environment scale and other covariables of interest were also available.

RESULTS

After adjustment, a doubling of DDE during the third trimester of pregnancy was associated with statistically significant reductions of -1.37, -0.88, -0.84, and -0.80 points in the general cognitive index, quantitative, verbal, and memory components respectively. The association between prenatal DDE and the quantitative component was weaker at 42 months than at older ages. No significant statistical interactions with sex or breastfeeding were observed.

CONCLUSIONS

These findings support the hypothesis that prenatal DDE impairs early child neurodevelopment; the potential for adverse effects on development should be considered when using DDT for malaria control.

Capsaicin consumption, Helicobacter pylori CagA status and IL1B-31C>T genotypes: a host and environment interaction in gastric cancer

Gastric cancer (GC) has been associated with a complex combination of genetic and environmental factors. In contrast to most countries, available information on GC mortality trends showed a gradual increase in Mexico. Our aim was to explore potential interactions among dietary (chili pepper consumption), infectious (Helicobacter pylori) and genetic factors (IL1B-31 genotypes) on GC risk. The study was performed in three areas of Mexico, with different GC mortality rates. We included 158 GC patients and 317 clinical controls. Consumption of capsaicin (Cap), the pungent active substance of chili peppers, was estimated by food frequency questionnaire. H. pylori CagA status was assessed by ELISA, and IL1B-31 genotypes were determined by TaqMan assays and Pyrosequencing in DNA samples. Multivariate unconditional logistic regression was used to estimate potential interactions. Moderate to high Cap consumption synergistically increased GC risk in genetically susceptible individuals (IL1B-31C allele carriers) infected with the more virulent H. pylori (CagA+) strains. The combined presence of these factors might explain the absence of a decreasing trend for GC in Mexico. However, further research on gene-environment interactions is required to fully understand the factors determining GC patterns in susceptible populations, with the aim of recommending preventive measures for high risk individuals.

Prenatal dichlorodiphenyldichloroethylene (DDE) exposure and child growth during the first year of life

BACKGROUND

Due to its long-term persistence in the environment and its ability to cross the placental barrier, prenatal p,p'-dichlorodiphenyldichloroethene (DDE) exposure continues to be a public health concern. This study aimed to evaluate the association between prenatal DDE exposure and child growth, at birth and during the first year of life.

METHODS

253 pregnant women were recruited between January 2001 and June 2005 in a prospective cohort in Morelos, Mexico. Serum levels of DDE were measured during each trimester of pregnancy by gas chromatography with an electron capture detector. Using the generalized mixed-effects models, the association between DDE and child growth parameters (weight-for-age, length-for-age, weight-for-length, BMI-for-age and head circumference-for-age Z-scores) from birth to 1 year of age was assessed. Maternal dietary intake was considered as covariable among others.

RESULTS

DDE levels were 6.3±2.8 ng/mL (first trimester), 6.6±2.9 ng/mL (second trimester), and 7.6±2.9 ng/mL (third trimester). After adjusting for potential confounder variables, no significant associations were observed with prenatal DDE exposure and each of the selected parameters.

CONCLUSIONS

Our results show no evidence of an association between prenatal DDE exposure and child growth during the first year of life.

Neonatal neurodevelopment and prenatal exposure to dichlorodiphenyldichloroethylene (DDE): a cohort study in Mexico

Prenatal exposure to dichlorodiphenyldichloroethylene (DDE) is associated with decreased motor development during the first year of life, though the effects of DDE in the neonatal stage are not conclusive. The main aim of this study was to evaluate the association between prenatal DDE exposure and neonatal neurodevelopment in a cohort from four municipalities in the state of Morelos, Mexico. The children (265), born from pregnancies with no perinatal complications, were evaluated at 1 month of age (± 7 days) for the presence of abnormal reflexes with the Brazelton Scale (NBAS), neurological soft signs with the Graham-Rosenblith Scale, as well as mental and psychomotor development by the Bayley Scales of Infant Development. Maternal DDE concentrations during each trimester of the pregnancy were determined by gas chromatography. Multiple linear and ordinal logistic models assessed the association between DDE and the outcomes of interest. Prenatal exposure to DDE was associated with a non-significant increase in neurological soft signs (6-8%) and a decrease in psychomotor (β(1T) = -0.02) and mental (β(2T) = -0.03 and β(3T) = -0.19) development. Our results are consistent with previous studies and suggest that prenatal DDE exposure is not associated with neurological functions present in the neonatal stage.

Phthalate exposure associated with self-reported diabetes among Mexican women

BACKGROUND

Phthalates are ubiquitous industrial chemicals used as plasticizers in plastics made of polyvinyl chloride (PVC) to confer flexibility and durability. They are also present in products used for personal-care, industry and in medical devices. Phthalates have been associated with several adverse health effects, and recently it has been proposed that exposure to phthalates, could have an effect on metabolic homeostasis. This exploratory cross-sectional study evaluated the possible association between phthalate exposure and self-reported diabetes among adult Mexican women.

METHODS

As part of an on-going case-control study for breast cancer, only controls were selected, which constituted 221 healthy women matched by age (±5 years) and place of residence with the cases. Women with diabetes were identified by self-report. Urinary concentrations of nine phthalate metabolites were measured by online solid phase extraction coupled to high performance liquid chromatography-isotope-dilution tandem mass spectrometry.

RESULTS

Participants with diabetes had significantly higher concentrations of di(2-ethylhexyl) pththalate (DEHP) metabolites: mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono(2-ethyl-5-carboxypentyl) phthalate (MECPP) but lower levels of monobenzyl phthalate (MBzP) a metabolite of benzylbutyl phthalate, compared to participants without diabetes. A marginally significant positive associations with diabetes status were observed over tertiles with MEHHP (OR(T3 vs. T1)=2.66; 95% CI: 0.97-7.33; p for trend=0.063) and MEOHP (OR(T3 vs. T1)=2.27; 95% CI; 0.90-5.75; P for trend=0.079) even after adjusting for important confounders.

CONCLUSIONS

The results suggest that levels of some phthalates may play a role in the genesis of diabetes.

Personal care product use and urinary levels of phthalate metabolites in Mexican women

Sources of phthalates other than Polyvinyl chloride (PVC) related products are scarcely documented in Mexico. The objective of our study was to explore the association between urinary levels of nine phthalate metabolites and the use of personal care products. Subjects included 108 women who participated as controls in an ongoing population-based case-control study of environmental factors and genetic susceptibility to breast cancer in northern Mexico. Direct interviews were performed to inquire about sociodemographic characteristics, reproductive history, use of personal care products, and diet. Phthalate metabolites measured in urine by high performance liquid chromatography-isotope dilution tandem mass spectrometry were monoethyl phthalate (MEP), monobenzyl phthalate (MBzP), mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), mono-3-carboxypropyl phthalate (MCPP) as well as mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP) that are metabolites of di-ethylhexyl phthalate (DEHP). Detectable urinary concentrations of phthalate metabolites varied from 75% (MEHP) to 100% (MEP, MBP, MEOHP, MEHHP and MECPP). Medians of urinary concentrations of some phthalate metabolites were significantly higher among users of the following personal care products compared to nonusers: body lotion (MEHHP, MECPP and sum of DEHP metabolites (ΣDEHP)), deodorant (MEHP and ΣDEHP), perfume (MiBP), anti-aging facial cream (MEP, MBP and MCPP) and bottled water (MCPP, MEHHP and MEOHP). Urinary concentrations of MEP showed a positive relationship with the number of personal care products used. Our results suggest that the use of some personal care products contributes to phthalate body burden that deserves attention due to its potential health impact.

[Government actions for the early detection of breast cancer in Latin America. Future challenges]

Documentary research carried out in 2009 aims to document the regulatory framework and existing programs for the early detection of breast cancer in Latin America and the Caribbean in order to establish the most important challenges for the containment of the epidemic in the region. The governments of the region have developed diverse efforts and initiatives to confront the rise in mortality due to said cause, including early detection, treatment and research strategies. Despite advances in the early detection of breast cancer, the challenge remains to link efforts to ensure continuity of care (diagnostic confirmation, treatment and monitoring) in order to achieve higher efficiency, effectiveness and benefits for women with this disease.

The association between first trimester micronutrient intake, MTHFR genotypes, and global DNA methylation in pregnant women

Objective

Our aim was to evaluate possible associations between consumption of micronutrients involved in one-carbon metabolism, MTHFR genotypes, and global DNA methylation in pregnant women.

Methods

A semi-quantitative dietary questionnaire was administered to 195 women during their first trimester in Morelos, Mexico. Two functional polymorphisms of the key folate-metabolizing gene, i.e. MTHFR 677 C>T and 1298 A>C, as well as global DNA methylation were assessed in peripheral blood drawn during the interview.

Results

Independent of maternal age and caloric intake, vitamin B₆ deficiency was associated with 1.8 fold increased risk of hypomethylation in women carrying the MTHFR 677 T allele.

Conclusions

There exists a subpopulation that is more susceptible to B vitamin deficiencies.

Resistance to antibiotics and characterization of Helicobacter pylori strains isolated from antrum and body from adults in Mexico

BACKGROUND AND AIMS

Resistance to antibiotics is common in patients with Helicobacter pylori infection in more than one anatomic stomach site. We assessed whether the antibiotic resistance varies according to virulence factors of the bacteria as well as to the age and gender of individuals infected in two anatomic sites.

METHODS

H. pylori strains were isolated from an antral and corpus biopsy from 90 patients with gastric ambulatory who had not received any previous therapy. Susceptibility to metronidazole and clarithromycin was assessed by E-test, and vacA and cagA genotypes were determined by polymerase chain reaction.

RESULTS

Dual resistance to metronidazole and clarithromycin was 3.3% in antrum and 4.4% in the corpus; heteroresistance was 19% and 5.5% for metronidazole and clarithromycin, respectively. Clarithromycin resistance significantly increased with age. Women showed a twofold increased risk for metronidazole-resistant strains in antrum (odds ratio = 2.85, 95% confidence interval 1.09 to 7.42). Virulence factors were not associated with antimicrobial resistance.

CONCLUSION

Prevalence of resistance to clarithromycin may be increasing in this country. Antimicrobial susceptibility tests from different biopsy sites deserve attention.

[Fumonisin intake and human health]

Fumonisins are mycotoxins that contaminate maize, disrupt the folate and sphingolipid metabolism, are associated with neural tube defects, and are considered by the International Agency for Research on Cancer (IARC) as possible human carcinogens. Since maize-based foods are significant components of the Mexican diet and there is a high prevalence of genetic susceptibility for folate deficiency among Mexicans, this essay presents international and national evidence of fumonisin exposure and the relevance that such exposure represents for Mexico.

[Breast cancer examination in Mexico: summary of the results from the National Survey of Reproductive Health]

OBJECTIVE

To present a summary of the results of the National Survey of Reproductive Health 2003 regarding the practice of self and clinical breast examination.

MATERIAL AND METHODS

The main sociodemographic characteristics and site of information about self and clinical breast examination, in 20 000 women 15 to 49 years of age residing in rural and urban areas, were identified by simple statistics and logistic regression models.

RESULTS

Younger women with lower scholarity and socioeconomical status residing in rural areas informed a statistically lower self and clinical breast examination. A higher frequency of breast cancer was found in rural vs. urban area.

CONCLUSIONS

Strategies for standardization and quality control for the clinical breast examination are needed to contribute in the prevention and control of breast cancer in Mexico.

Breast cancer mortality in Mexico: an age-period-cohort analysis

OBJECTIVE

To assess the age, period and cohort effects on breast cancer (BC) mortality in Mexico.

MATERIAL AND METHODS

Age, period and cohort curvature trends for BC mortality were estimated through the Poisson Regression model proposed by Holford.

RESULTS

Nationally, BC death rates have leveled off since 1995 in most age groups. BC mortality trends are mainly determined by birth cohort and age effects in Mexico. Women born between 1940 and 1955 show the highest rate of increase in BC mortality. Women born afterwards still show an increasing trend but at a much lower rate. Mammography and adjuvant therapy have had a limited impact on mortality. Potential reasons for observed patterns are discussed. An increase in BC mortality in Mexico is expected in the following decades.

CONCLUSIONS

Mammography screening programs and timely access to effective treatment should be a national priority to reverse the expected increasing BC mortality trend.

Exposure to phthalates and breast cancer risk in northern Mexico

BACKGROUND

Phthalates, ubiquitous environmental pollutants that may disturb the endocrine system, are used primarily as plasticizers of polyvinyl chloride and as additives in consumer and personal care products.

OBJECTIVES

In this study, we examined the association between urinary concentrations of nine phthalate metabolites and breast cancer (BC) in Mexican women.

METHODS

We age-matched 233 BC cases to 221 women residing in northern Mexico. Sociodemographic and reproductive characteristics were obtained by direct interviews. Phthalates were determined in urine samples (collected pretreatment from the cases) by isotope dilution/high-performance liquid chromatography coupled to tandem mass spectrometry.

RESULTS

Phthalate metabolites were detected in at least 82% of women. The geometric mean concentrations of monoethyl phthalate (MEP) were higher in cases than in controls (169.58 vs. 106.78 microg/g creatinine). Controls showed significantly higher concentrations of mono-n-butyl phthalate, mono(2-ethyl-5-oxohexyl) phthalate, and mono(3-carboxypropyl) phthalate (MCPP) than did the cases. After adjusting for risk factors and other phthalates, MEP urinary concentrations were positively associated with BC [odds ratio (OR), highest vs. lowest tertile = 2.20; 95% confidence interval (CI), 1.33-3.63; p for trend < 0.01]. This association became stronger when estimated for premenopausal women (OR, highest vs. lowest tertile = 4.13; 95% CI, 1.60-10.70; p for trend < 0.01). In contrast, we observed significant negative associations for monobenzyl phthalate (MBzP) and MCPP.

CONCLUSIONS

We show for the first time that exposure to diethyl phthalate, the parent compound of MEP, may be associated with increased risk of BC, whereas exposure to the parent phthalates of MBzP and MCPP might be negatively associated. These findings require confirmation.

Helicobacter pylori, nutrition and smoking interactions: their impact in gastric carcinogenesis

Gastric cancer (GC) is the result of a long multi-step and multifactorial process involving possible interactions between Helicobacter pylori infection, environmental exposures and host genetic susceptibility. Interactions between H. pylori infection, tobacco smoking and dietary antioxidants are biologically plausible. Positive interactions between risk factors imply that, in certain subgroups of the population, the risk of GC associated with simultaneous exposure to these factors is higher than that in the rest of the population, and these subgroups have to be the target for preventive measures. Using PubMed, we reviewed all studies published in English up to December 2008 carried out in humans on interactions between H. pylori infection and smoking exposure and between H. pylori infection and dietary factors in gastric carcinogenesis. Although relatively few epidemiological studies have evaluated the effect of the interaction between smoking and H. pylori infection on GC risk, there is a suggestion of a positive interaction between the two factors. In contrast, evidence suggests a negative interaction between dietary antioxidants and H. pylori infections on GC risk. The potential protective effect of dietary antioxidants such as vitamins C and E and beta-carotene seems to be stronger in those infected by H. pylori, even though results are inconsistent. In Asian populations, subjects infected by H. pylori and with high dietary salt intake may have a higher risk of GC than subjects without H. pylori infection and with a low salt intake. The risk of GC associated with red meat, processed meat or endogenous formation of nitrosamines appears to only be observed in subjects infected by H. pylori. More and larger epidemiological studies, mainly prospective studies, are necessary to reach a more definitive conclusion on these interactions.