Additive or Interactive Associations of Food Allergies with Glutathione S-Transferase Genes in Relation to ASD and ASD Severity in Jamaican Children.

To investigate additive and interactive associations of food allergies with three glutathione S-transferase (GST) genes in relation to ASD and ASD severity in Jamaican children. Using data from 344 1:1 age- and sex-matched ASD cases and typically developing controls, we assessed additive and interactive associations of food allergies with polymorphisms in GST genes (GSTM1, GSTP1 and GSTT1) in relation to ASD by applying conditional logistic regression models, and in relation to ASD severity in ASD cases as measured by the Autism Diagnostic Observation Schedule-2nd Edition (ADOS-2) total and domains specific comparison scores (CSs) by fitting general linear models. Although food allergies and GST genes were not associated with ASD, ASD cases allergic to non-dairy food had higher mean ADOS-2 Restricted and Repetitive Behaviors (RRB) CS (8.8 vs. 8.0, P = 0.04). In addition, allergy to dairy was associated with higher mean RRB CS only among ASD cases with GSTT1 DD genotype (9.9 vs. 7.8, P < 0.01, interaction P = 0.01), and GSTP1 Val/Val genotype under a recessive genetic model (9.8 vs. 7.8, P = 0.02, interaction P = 0.06). Our findings are consistent with the role for GST genes in ASD and food allergies, though require replication in other populations.

Interactions between Environmental Factors and Glutathione S-Transferase (GST) Genes with Respect to Detectable Blood Aluminum Concentrations in Jamaican Children.

Aluminum (Al) is a metallic toxicant at high concentrations following natural or unnatural exposures. Dietary intake is considered as the main source of aluminum exposure in children. We used data from 366 typically developing (TD) children (ages 2−8 years) who participated as controls in an age- and sex-matched case−control study in Jamaica. We investigated additive and interactive associations among environmental factors and children's genotypes for glutathione S-transferase (GST) genes (GSTT1, GSTM1, GSTP1), in relation to having a detectable blood aluminum concentration (BAlC) of >5.0 µg/L, using multivariable logistic regression models. Findings from interactive models revealed that the odds of having a detectable BAlC was significantly higher among children who ate string beans (p ≤ 0.01), whereas about 40% lower odds of having a detectable BAlC was observed in children with higher parental education level, (p = 0.02). A significant interaction between consumption of saltwater fish and GSTP1 in relation to having a detectable BAlC using either co-dominant or dominant genetic models (overall interaction p = 0.02 for both models) indicated that consumption of saltwater fish was associated with higher odds of having a detectable BAlC only among children with the GSTP1 Ile105Val Ile/Ile genotype using either co-dominant or dominant models [OR (95% CI) = 2.73 (1.07, 6.96), p = 0.04; and OR (95% CI) = 2.74 (1.08, 6.99), p = 0.03]. Since this is the first study from Jamaica that reports such findings, replication in other populations is warranted.

Neonatal morbidity in the 2011 JAKIDS Jamaican birth cohort.

This study reports the spectrum of discharge diagnoses in a national cohort of newborns admitted during a 3-month period to hospitals across Jamaica. The data were analyzed using measures of central tendency and risk assessed using odds ratio. Data on 1607 admissions were used to describe the spectrum of morbidity in hospitalized infants. Eight hundred and seven (50%) male and 754 (48%) female neonates were admitted. There was a 15% (240) readmission rate during the neonatal period. Infants of diabetic mothers were almost three times as likely to be admitted as infants whose mothers were not diabetic OR 2.89 (CI 1.96 - 4.13). Infants of women who were hypertensive were 1.5 times more likely to be admitted than infants of non-hypertensive women OR 1.56 (CI 1.56-1.9). The odds ratio for admission of an infant born to a woman delivered by caesarean section was 2.1 (CI: 1.67-2.38). Premature infants constituted 50% of admissions. The most prevalent discharge diagnosis included presumed sepsis, respiratory distress and neonatal jaundice in both preterm and term neonates. In the extreme preterm infant respiratory distress syndrome was the most predominant discharge diagnosis. Multiple gestation was a significant risk for admission OR 2.7 (CI 1.8 to 3.9). Prematurity, multiple gestation, macrosomia, maternal diabetes, maternal hypertension and low 5 minute Apgar score < 7 were all found to be independent predictors of neonatal admission in a logistic regression model (p < 0.001). The recognition of the discharge morbidity is useful for future health planning for the most vulnerable in our population.

Neonatal mortality in the 2011 JAKIDS birth cohort.

This study aimed to determine the mortality in a Jamaican birth cohort over a 3-month period. Data on the outcome of 87.5% of all births in Jamaica between July and September 2011 were used to determine trends in and determinants of neonatal mortality. There were 9650 live births and 144 neonatal deaths yielding a Neonatal Mortality Rate of 14.9/1000 (95% CI: 12.6-17.52/1000) livebirths. One hundred and twenty-one (84%) deaths occurred within the first seven days of life giving an Early Neonatal Mortality Rate of 12.5/1000 (95%CI: 10.4-15.0/1000) livebirths and a Late Neonatal Mortality Rate of 2.38/1000 (95%CI: 1.51-3.57/1000) live births. Sixty-nine (48%) deaths occurred within the first 24 hours. Thirty-eight neonates (26%) died prior to being admitted to a neonatal unit, approximately within 2 hours of life.Maternal age <15 years, decreasing birthweight, prematurity, male gender, multiple gestation and birth by caesarean section were associated with an increased risk of mortality p < 0.05. In order for Jamaica to experience further decline in its Neonatal Mortality Rate to meet the Sustainable Developmental Goal of at least as low as 12 per 1,000 live births by 2030 the focus must be on decreasing mortality in the very low birth weight infants who disproportionally contribute to mortality as well as continuing to implement measures to further decrease mortality in the larger infants.

Interaction of Blood Manganese Concentrations with GSTT1 in Relation to Autism Spectrum Disorder in Jamaican Children.

Using data from 266 age- and sex-matched pairs of Jamaican children with autism spectrum disorder (ASD) and typically developing (TD) controls (2-8 years), we investigated whether glutathione S-transferase theta 1 (GSTT1) modifies the association between blood manganese concentrations (BMC) and ASD. After adjusting conditional logistic regression models for socioeconomic status and the interaction between GSTT1 and GSTP1 (glutathione S-transferase pi 1), using a recessive genetic model for GSTT1 and either a co-dominant or dominant model for GSTP1, the interaction between GSTT1 and BMC was significant (P = 0.02, P = 0.01, respectively). Compared to controls, ASD cases with GSTT1-DD genotype had 4.33 and 4.34 times higher odds of BMC > 12 vs. ≤ 8.3 µg/L, respectively. Replication in other populations is warranted.

Interaction between a Mixture of Heavy Metals (Lead, Mercury, Arsenic, Cadmium, Manganese, Aluminum) and GSTP1, GSTT1, and GSTM1 in Relation to Autism Spectrum Disorder.

BACKGROUND: Exposure to many environmental chemicals, including metals, often does not occur in isolation, hence requires assessment of the associations between exposure to mixtures of chemicals and human health. OBJECTIVES: To investigate associations of a metal mixture of lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), manganese (Mn), and aluminum (Al) in children with autism spectrum disorder (ASD), additively or interactively with each of three glutathione S-transferase (GST) genes (GSTP1, GSTT1, and GSTM1). METHOD: Using data from 266 case-control pairs of Jamaican children (2-8 years old), we fitted negative and positive generalized weighted quantile sum (gWQS) regression models to assess the aforementioned associations. RESULTS: Based on additive and interactive negative gWQS models adjusted for maternal age, parental education, child's parish, and seafood consumption, we found inverse associations of the overall mixture score with ASD [MOR (95% CI): 0.70 (0.49, 0.99); P < 0.05) and [MOR (95%CI): 0.46 (0.25, 0.84); P = 0.01], respectively. In an unadjusted negative gWQS model, we found a marginally significant interaction between GSTP1 and a mixture of three metals (Pb, Hg, and Mn) (P = 0.07) while the association was no longer significant after adjustment for the same covariates (P = 0.24). CONCLUSIONS: Differences in diet between ASD and control groups may play a role in the inverse associations we found. The possible interactive association between Mn and GSTP1 in ASD based on gWQS is consistent with our previous reports. However, possible interaction of GSTP1 with Pb and Hg in ASD requires further investigation and replication.

Association of Polychlorinated Biphenyls and Organochlorine Pesticides with Autism Spectrum Disorder in Jamaican Children.

BACKGROUND: Polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides are suspected to play a role in autism spectrum disorder (ASD). OBJECTIVES: To investigate associations of PCBs and OC pesticides with ASD in Jamaican children and explore possible interaction between PCBs or OC pesticides with glutathione S-transferase (GST) genes (GSTT1, GSTM1, GSTP1) in relation to ASD. METHODS: Participants included n=169 age- and sex-matched case-control pairs of Jamaican children 2-8 years old. Socioeconomic status and food frequency data were self-reported by the parents/guardians. Blood from each participant was analyzed for 100 PCB congeners and 17 OC pesticides and genotyped for three GST genes. PCBs and OC pesticides concentrations below the limit of detection (LoD) were replaced with (LoD/√2). We used conditional logistic regression (CLR) models to assess associations of PCBs and OC pesticides with ASD, individually or interactively with GST genes (GSTT1, GSTM1, GSTP1). RESULTS: We found inverse associations of PCB-153 [adjusted MOR (95% CI) = 0.44 (0.23-0.86)] and PCB-180 [adjusted MOR (95% CI) = 0.52 (0.28-0.95)] with ASD. When adjusted for covariates in a CLR the interaction between GSTM1 and PCB-153 became significant (P < 0.01). DISCUSSION: Differences in diet between ASD and typically developing control groups may play a role in the observed findings of lower concentrations of PCB-153 and PCB-180 in individuals with ASD than in controls. Considering the limited sample size and high proportion of concentrations below the LoD, these results should be interpreted with caution but warrant further investigation into associations of PCBs and OC pesticides with ASD.

Perinatal Factors Associated with Autism Spectrum Disorder in Jamaican Children.

Mode of delivery, preterm birth, and low birth weight (LBW) are hypothesized to be associated with autism spectrum disorder (ASD) in the offspring. Using data from 343 ASD cases (2-8 years) and their age- and sex-matched typically developing controls in Jamaica we investigated these hypotheses. Our statistical analyses revealed that the parish of residence could modify the association between cesarean delivery and ASD, with a difference found in this relationship in Kingston parish [matched odds ratio (MOR) (95% confidence interval (CI)) 2.30 (1.17-4.53)] and other parishes [MOR (95% CI) 0.87 (0.48-1.59)]. Although the associations of LBW and preterm birth with ASD were not significant, we observed a significant interaction between LBW and the household socioeconomic status. These findings require replication.

A generalized weighted quantile sum approach for analyzing correlated data in the presence of interactions.

A weighted quantile sum (WQS) regression has been used to assess the associations between environmental exposures and health outcomes. However, the currently available WQS approach, which is based on additive effects, does not allow exploring for potential interactions of exposures with other covariates in relation to a health outcome. In addition, the current WQS cannot account for clustering, thus it may not be valid for analysis of clustered data. We propose a generalized WQS approach that can assess interactions by estimating stratum-specific weights of exposures in a mixture, while accounting for potential clustering effect of matched pairs of cases and controls as well as censored exposure data due to being below the limits of detection. The performance of the proposed method in identifying interactions is evaluated through simulations based on various scenarios of correlation structures among the exposures and with an outcome. We also assess how well the proposed method performs in the presence of the varying levels of censoring in exposures. Our findings from the simulation study show that the proposed method outperforms the traditional WQS, as indicated by higher power of detecting interactions. We also find no strong evidence that the proposed method falsely identifies interactions when there are no true interactive effects. We demonstrate application of the proposed method to real data from the Epidemiological Research on Autism Spectrum Disorder (ASD) in Jamaica (ERAJ) by examining interactions between exposure to manganese and glutathione S-transferase family gene, GSTP1 in relation to ASD.

Maternal Exposures Associated with Autism Spectrum Disorder in Jamaican Children.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with poorly understood etiology. Many maternal exposures during pregnancy and breastfeeding potentially interfere with neurodevelopment. Using data from two age- and sex-matched case-control studies in Jamaica (n = 298 pairs), results of conditional logistic regression analyses suggest that maternal exposures to fever or infection (matched odds ratio (MOR) = 3.12, 95% CI 1.74-5.60), physical trauma (MOR 2.02, 95% CI 1.01-4.05), and oil-based paints (MOR 1.99, 95% CI 1.14-3.46) may be associated with ASD. Additionally, maternal exposure to oil-based paints may modify the relationship between maternal exposure to pesticides and ASD, which deepens our understanding of the association between pesticides and ASD.

Antenatal depressive symptoms in Jamaica associated with limited perceived partner and other social support: A cross-sectional study.

BACKGROUND: Antenatal depression is associated with adverse maternal and infant well-being. However, compared to postpartum depression, it has been less frequently explored globally or in Jamaica. This study aimed to determine the prevalence of, and factors associated with, antenatal depressive symptoms among Jamaican women in order to inform policy and build interventions that could improve their management and reduce their negative consequences. METHODS: This secondary analysis of data from the second Jamaican Birth Cohort Study (JA-Kids Birth Cohort) included 3,517 women enrolled during pregnancy. Information was extracted from interviewer-administered questionnaires which recorded social, demographic, medical and obstetric information during pregnancy. The Edinburgh Postnatal Depression scale (EPDS) was used to screen for depression, with scores ≥13 considered indicative of a high likelihood of depression. Bivariate analysis examined associations between depressive symptoms and: age, income, financial difficulties, perceived social support, perceived partner infidelity, previous child-bearing unions and children with the current partner. Obstetric factors were also explored and included gravidity, prior adverse pregnancy outcome and complications from previous pregnancies. Variables that predicted the likelihood of depression based on an EPDS cut score of 13 were evaluated using logistic regression. RESULTS: One in five participants (19.6%; 95% CI 18.3-20.9%) had a high likelihood of antenatal depression (EPDS ≥13). Significant predictors of high depressive symptom severity included four indicators of poor perceived social and partner support [ORs (95% CI) ranged from: 1.61 (1.07-2.43); p = 0.024 to 3.14(1.69-5.84); p< 0.001], perceived partner infidelity [1.86 (1.36, 2.54); p<0.001], exposure to violence [2.36 (1.66-3.38); p<0.001] and financial difficulties [1.39 (1.07, 1.80); p = 0.013]. CONCLUSIONS: Women's perceived social and partner support were strongly associated with depressive symptom severity. Within the Jamaican cultural context of unstable reproductive unions, efforts are needed to involve fathers in the antenatal care process to strategically improve the psychological well-being of new mothers which may positively influence long term developmental outcomes for their babies.

Interaction between manganese and GSTP1 in relation to autism spectrum disorder while controlling for exposure to mixture of lead, mercury, arsenic, and cadmium.

BACKGROUND: We previously reported a significant interactive association between polymorphisms of GSTP1 and blood manganese concentrations (BMC) with autism spectrum disorder (ASD) in Jamaican children. In this paper, we investigate the same interactive association with ASD while adjusting for the mixture of four metals (lead, mercury, cadmium, and arsenic). METHOD: We used data from 163 case-control pairs of children 2-8 years of age from our autism project in Jamaica, in which we collected blood for heavy metals analysis at enrollment. To minimize potential multicollinearity between concentrations of the four metals, we generated a mixture index using generalized weighted quantile sum regression, which was used in conditional logistic regression models to control for the four metals while assessing the interactive association between GSTP1 and BMC with ASD. RESULTS: Similar to the findings we reported previously, we found that in co-dominant and dominant models for GSTP1, among children with the Ile/Ile genotype, those with BMC > 12µg/L had 4.6 and 4.27 times higher odds of ASD compared to those with BMC < 12µg/L (adjusted Matched Odds Ratio (MOR) = 4.6, 95% CI: 1.21 - 17.42 and adjusted MOR = 4.27, 95% CI: 1.15 - 15.85, respectively). In the co-dominant model, for children with the Ile/Val and Val/Val genotypes, the adjusted MORs were 1.26 (95% CI: 0.32, 5.01) and 0.26 (95% CI: 0.05, 1.42), respectively. CONCLUSIONS: After adjusting for the mixture of four metals, the interactive association of BMC and GSTP1 with ASD remained significant with similar magnitude of associations. Results should be interpreted cautiously.

The diagnosis of autism and autism spectrum disorder in low- and middle-income countries: Experience from Jamaica.

The administration requirements of the Autism Diagnostic Observation Schedule and the Autism Diagnostic Interview-Revised, widely used in high-income countries, make them less feasible for diagnosis of autism spectrum disorder in low- and middle-income countries. The flexible administration requirements of the Childhood Autism Rating Scale have resulted in its use in both high-income countries and low- and middle-income countries. This study examines the agreement between assessments using the Childhood Autism Rating Scale with those using the Autism Diagnostic Observation Schedule or Autism Diagnostic Observation Schedule, Second Edition and Autism Diagnostic Interview-Revised in Jamaica. Children aged 2-8 years (n = 149) diagnosed with autism by an experienced clinician using the Childhood Autism Rating Scale were re-evaluated using the Autism Diagnostic Observation Schedule and Autism Diagnostic Interview-Revised. The proportion diagnosed with autism spectrum disorder using the Autism Diagnostic Observation Schedule, Autism Diagnostic Observation Schedule, Second Edition, and Autism Diagnostic Interview-Revised was determined and mean domain scores compared using analysis of variance (ANOVA). The mean age was 64.4 (standard deviation = 21.6) months; the male:female ratio was 6:1. The diagnostic agreement of the Childhood Autism Rating Scale with the Autism Diagnostic Observation Schedule and Autism Diagnostic Observation Schedule, Second Edition was 100.0% and 98.0%, respectively. Agreement with the Autism Diagnostic Interview-Revised was 94.6%. Domain scores were highest for children with more severe symptoms (p < 0.01). Despite a high level of agreement of the Childhood Autism Rating Scale with the Autism Diagnostic Observation Schedule, Autism Diagnostic Observation Schedule, Second Edition, and Autism Diagnostic Interview-Revised, the Childhood Autism Rating Scale should be evaluated further with a broader range of autism spectrum disorder symptomatology, and by clinicians with varying experience before recommendation for use in low- and middle-income countries.

The prevention of violence in childhood through parenting programmes: a global review.

Child maltreatment is a global problem affecting both high income (HICs) and low and middle income countries (LMICs). However research has shown that children who live in the world's poorest countries and communities are more likely to suffer from abuse and neglect. There is some evidence that parenting interventions can assist in the prevention of child maltreatment, but most of this research has been conducted in HICs. The main aim of this review was to examine the evidence from previous systematic reviews on the role of parenting programmes in the prevention of violence against children in both HICs and LMICs. A comprehensive internet search was conducted for published and unpublished reviews. After reviewing abstracts and full texts against established criteria for inclusion in the study, 28 reviews (20 systematic reviews/meta-analyses and 8 comprehensive reviews) were used in the analyses. The findings suggest that parenting programmes have the potential to both prevent and reduce the risk of child maltreatment. However, there is lack of good evidence from LMICs where the risk of child maltreatment is greatest. Implications for policy and future research are discussed, especially for the LMIC context.

Role of Metabolic Genes in Blood Aluminum Concentrations of Jamaican Children with and without Autism Spectrum Disorder.

Aluminum is a neurotoxic metal with known health effects in animals and humans. Glutathione-S-transferase (GST) genes and enzymes play a major role in detoxification of several heavy metals. Besides a direct relationship with oxidative stress; aluminum decreases GST enzyme activities. Using data from 116 Jamaican children; age 2-8 years; with Autism Spectrum Disorder (ASD) and 116 sex- and age-matched typically developing (TD) children; we investigated the association of polymorphisms in three GST genes (GSTP1; GSTM1; and GSTT1) with mean blood aluminum concentrations in children with and without ASD. Using log-transformed blood aluminum concentration as the dependent variable in a linear regression model; we assessed the additive and interactive effects of ASD status and polymorphisms in the three aforementioned GST genes in relation to blood aluminum concentrations. Although none of the additive effects were statistically significant (all p > 0.16); we observed a marginally significant interaction between GSTP1 Ile105Val (rs1695) and ASD status (p = 0.07); even after controlling for parental education level and consumption of avocado; root vegetables; and tuna (canned fish). Our findings indicate a significantly lower (p < 0.03) adjusted geometric mean blood aluminum concentration for TD children who had the Val/Val genotype (14.57 µg/L); compared with those with Ile/Ile or Ile/Val genotypes who had an adjusted geometric mean of 23.75 µg/L. However; this difference was not statistically significant among the ASD cases (p = 0.76). Our findings indicate that ASD status may be a potential effect modifier when assessing the association between GSTP1 rs1695 and blood aluminum concentrations among Jamaican children. These findings require replication in other populations.

Concentrations of Polychlorinated Biphenyls and Organochlorine Pesticides in Umbilical Cord Blood Serum of Newborns in Kingston, Jamaica.

To date much of the biomonitoring related to exposure to polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides is from middle to high income countries, including the U.S., Canada and Europe, but such data are lacking for the majority of low to middle income countries. Using data from 64 pregnant mothers who were enrolled in 2011, we aimed to assess the concentrations of the aforementioned toxins in umbilical cord blood serum of 67 Jamaican newborns. For 97 of the 100 PCB congeners and 16 of the 17 OC pesticides, all (100%) concentrations were below their respective limits of detection (LOD). Mean (standard deviation (SD)) lipid-adjusted concentrations in cord blood serum for congeners PCB-153, PCB-180, PCB-206 and total PCB were 14.25 (3.21), 7.16 (1.71), 7.30 (1.74) and 28.15 (6.03) ng/g-lipid, respectively. The means (SD) for the 4,4'-dichlorodiphenyldichloroethylene (DDE)-hexane fraction and total-DDE were 61.61 (70.78) and 61.60 (70.76) ng/g-lipid, respectively. Compared to the U.S. and Canada, the concentrations of these toxins were lower in cord-blood serum of Jamaican newborns. We discuss that these differences could be partly due to differences in dietary patterns in these countries. Despite limitations in our dataset, our results provide information on the investigated toxins in cord blood serum that could serve as a reference for Jamaican newborns.

Synergic effect of GSTP1 and blood manganese concentrations in Autism Spectrum Disorder.

We used data from 100 age- and sex-matched case-control pairs (age 2-8 years) from Jamaica to investigate whether there is an interaction between glutathione-S-transferase (GST) genes and blood manganese concentrations (BMC) in relation to Autism Spectrum Disorder (ASD). Our findings, indicate that among children who had the Ile/Ile genotype for GST pi 1 (GSTP1), those with BMC ≥ 12µg/L had about 4 times higher odds of ASD than those with BMC < 12µg/L, (P=0.03) under a co-dominant genetic model. After adjusting for potential confounders, among the subgroup of children with genotype Ile/Ile, those with BMC ≥ 12µg/L had about six times higher odds of ASD than those with BMC < 12µg/L, (P=0.04). The results were similar when a recessive genetic model was used. These findings suggest a possible synergic effect of BMC and GSTP1 in ASD. Since our analysis included a variety of genetic models and was not adjusted for multiple testing, replication in other populations is warranted.

Concentration of lead, mercury, cadmium, aluminum, arsenic and manganese in umbilical cord blood of Jamaican newborns.

The objective of this study was to characterize the concentrations of lead, mercury, cadmium, aluminum, and manganese in umbilical cord blood of Jamaican newborns and to explore the possible association between concentrations of these elements and certain birth outcomes. Based on data from 100 pregnant mothers and their 100 newborns who were enrolled from Jamaica in 2011, the arithmetic mean (standard deviation) concentrations of cord blood lead, mercury, aluminum, and manganese were 0.8 (1.3 µg/dL), 4.4 (2.4 µg/L), 10.9 (9.2 µg/L), and 43.7 (17.7 µg/L), respectively. In univariable General Linear Models, the geometric mean cord blood aluminum concentration was higher for children whose mothers had completed their education up to high school compared to those whose mothers had any education beyond high school (12.2 µg/L vs. 6.4 µg/L; p < 0.01). After controlling for maternal education level and socio-economic status (through ownership of a family car), the cord blood lead concentration was significantly associated with head circumference (adjusted p < 0.01). Our results not only provide levels of arsenic and the aforementioned metals in cord blood that could serve as a reference for the Jamaican population, but also replicate previously reported significant associations between cord blood lead concentrations and head circumference at birth in other populations.

Factors associated with blood lead concentrations of children in Jamaica.

Lead is a heavy metal known to be detrimental to neurologic, physiologic, and behavioral health of children. Previous studies from Jamaica reported that mean lead levels in soil are four times that of lead levels in some other parts of the world. Other studies detected lead levels in fruits and root vegetables, which were grown in areas with lead contaminated soil. In this study, we investigate environmental factors associated with blood lead concentrations in Jamaican children. The participants in this study comprised 125 typically developing (TD) children (ages 2-8 years) who served as controls in an age- and sex-matched case-control study that enrolled children from 2009-2012 in Jamaica. We administered a questionnaire to assess demographic and socioeconomic information as well as potential exposures to lead through food. Using General Linear Models (GLMs), we identified factors associated with blood lead concentrations in Jamaican children. The geometric mean blood lead concentration (GMBLC) in the sample of children in this study was 2.80 µg dL(-1). In univariable GLM analyses, GMBLC was higher for children whose parents did not have education beyond high school compared to those whose parents had attained this level (3.00 µg dL(-1) vs. 2.31 µg dL(-1); P = 0.05), children living near a high traffic road compared to those who did not (3.43 µg dL(-1) vs. 2.52 µg dL(-1); P < 0.01), and children who reported eating ackee compared to those who did not eat this fruit (2.89 µg dL(-1) vs. 1.65 µg dL(-1); P < 0.05). In multivariable analysis, living near a high traffic road was identified as an independent risk factor for higher adjusted GMBLC (3.05 µg dL(-1) vs. 2.19 µg dL(-1); P = 0.01). While our findings indicate that GMBLC in Jamaican children has dropped by at least 62% during the past two decades, children living in Jamaica still have GMBLC that is twice that of children in more developed countries. In addition, we have identified significant risk factors for higher blood lead concentrations in Jamaican children. We believe increasing awareness among parents regarding these risk factors could potentially lead to a lower level of lead exposure in Jamaican children.

Interaction between GSTT1 and GSTP1 allele variants as a risk modulating-factor for autism spectrum disorders.

We investigated the role of glutathione S-transferase (GST) genes in Autism Spectrum Disorder (ASD). We used data from 111 pairs of age- and sex-matched ASD cases and typically developing (TD) controls between 2-8 years of age from Jamaica to investigate the role of GST pi 1 (GSTP1), GST theta 1 (GSTT1), and GST mu 1 (GSTM1) polymorphisms in susceptibility to ASD. In univariable conditional logistic regression models we did not observe significant associations between ASD status and GSTT1, GSTM1, or GSTP1 genotype (all P > 0.15). However, in multivariable conditional logistic regression models, we identified a significant interaction between GSTP1 and GSTT1 in relation to ASD. Specifically, in children heterozygous for the GSTP1 Ile105Val polymorphism, the odds of ASD was significantly higher in those with the null GSTT1 genotype than those with the other genotypes [Matched Odds Ratio (MOR) = 2.97, 95% CI (1.09, 8.01), P = 0.03]. Replication in other populations is warranted.