Metabolomic profiles in Jamaican children with and without autism spectrum disorder

Background

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with a wide range of behavioral and cognitive impairments. While genetic and environmental factors are known to contribute to its etiology, the underlying metabolic perturbations associated with ASD which can potentially connect genetic and environmental factors, remain poorly understood. Therefore, we conducted a metabolomic case-control study and performed a comprehensive analysis to identify significant alterations in metabolite profiles between children with ASD and typically developing (TD) controls.

Objective

To elucidate potential metabolomic signatures associated with ASD in children and identify specific metabolites that may serve as biomarkers for the disorder.

Methods

We conducted metabolomic profiling on plasma samples from participants in the second phase of Epidemiological Research on Autism in Jamaica (ERAJ-2), which was a 1:1 age (±6 months)-and sex-matched cohort of 200 children with ASD and 200 TD controls (2-8 years old). Using high-throughput liquid chromatography-mass spectrometry techniques, we performed a targeted metabolite analysis, encompassing amino acids, lipids, carbohydrates, and other key metabolic compounds. After quality control and imputation of missing values, we performed univariable and multivariable analysis using normalized metabolites while adjusting for covariates, age, sex, socioeconomic status, and child's parish of birth.

Results

Our findings revealed unique metabolic patterns in children with ASD for four metabolites compared to TD controls. Notably, three of these metabolites were fatty acids, including myristoleic acid, eicosatetraenoic acid, and octadecenoic acid. Additionally, the amino acid sarcosine exhibited a significant association with ASD.

Conclusions

These findings highlight the role of metabolites in the etiology of ASD and suggest opportunities for the development of targeted interventions.

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.

Factors associated with blood mercury concentrations and their interactions with three glutathione S-transferase genes (GSTT1, GSTM1, and GSTP1): an exposure assessment study of typically developing Jamaican children

BACKGROUND

Jamaican soil is abundant in heavy metals including mercury (Hg). Due to availability and ease of access, fish is a traditional dietary component in Jamaica and a significant source of Hg exposure. Mercury is a xenobiotic and known neuro-toxicant that affects children's neurodevelopment. Human glutathione S-transferase (GST) genes, including GSTT1, GSTM1, and GSTP1, affect Hg conjugation and elimination mechanisms.

METHODS

In this exposure assessment study we used data from 375 typically developing (TD) 2-8-year-old Jamaican children to explore the association between environmental Hg exposure, GST genes, and their interaction effects on blood Hg concentrations (BHgCs). We used multivariable general linear models (GLMs).

RESULTS

We identified the child's age, consumption of saltwater fish, canned fish (sardine, mackerel), string beans, grain, and starches (pasta, macaroni, noodles) as the environmental factors significantly associated with BHgCs (all P < 0.05). A significant interaction between consumption of canned fish (sardine, mackerel) and GSTP1 in relation to BHgC using either a co-dominant or recessive genetic model (overall interaction P = 0.01 and P < 0.01, respectively) indicated that consumption of canned fish (sardine, mackerel) was significantly associated with higher mean BHgC only among children with the GSTP1 Ile105Val, Ile/Ile [Ratio of mean Hg (95% CI) = 1.59 (1.09, 2.32), P = 0.02] and Ile/Val [Ratio of mean Hg (95% CI) = 1.46 (1.12, 1.91), P = 0.01] genotypes.

CONCLUSIONS

Since this is the first study from Jamaica to report these findings, replication in other populations is recommended.

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.

***ECD*** maternal C-reactive protein as a predictor of neonatal sepsis

Systemic bacterial infection in the newborn has a significant impact on neonatal mortality and morbidity. Non-invasive prenatal markers of risk could be useful in the prediction and prevention of neonatal sepsis. We evaluated the association of maternal third-trimester serum level of C-Reactive Protein (CRP) with neonatal sepsis in a sample of infants in the JAKids pregnancy and birth cohort study. A population-based nested case-control design was used to identify cases and controls of neonatal sepsis from the subset of infants in the JAKids study whose mothers had serum archived in the early third trimester and who were admitted to newborn intensive care. Cases were 25 neonates with neonatal sepsis identified from hospital records. Controls were a random sample of 62 sepsis-free neonates matched to cases within three gestational age strata - ≤32 weeks, 33-36 weeks, and ≥37 weeks.Mothers of neonatal sepsis cases ≥37 weeks had significantly higher mean levels of maternal CRP protein than mothers of controls (11.0 mg/dL ± 3.0 vs. 8.7 mg/dL ± 5.9; p < .05). Differences in maternal CRP were not found in sepsis cases born ≤32 weeks (9.5 mg/dL ± 4.2 vs 5.8 mg/dL ± 4.0, p = .23) nor in sepsis cases born at 33-36 weeks (9.0 mg/dL ± 3.6 vs 11.9 mg/dL ± 7.8, p = .34). Maternal third-trimester C-reactive protein levels were elevated in mothers of term-born neonates with sepsis, but not in the mothers of preterm neonates with sepsis.

Correlation between concentrations of four heavy metals in cord blood and childhood blood of Jamaican children

This study investigated whether the concentrations of four metals [lead (Pb), mercury (Hg), manganese (Mn), and aluminum (Al)] are correlated in cord blood and childhood blood samples from Jamaican children. Cord blood samples were obtained from 21 pregnant women enrolled in the second Jamaican Birth Cohort Study from July 1, 2011 to September 30, 2011, and blood samples were drawn from their children who participated in a follow up study when the children were 4-8 years old. Correlations were assessed by the Pearson or the Spearman's rank correlation coefficient. The mean ages of children at the childhood visit and their mother at the child's birth were 5.5 years and 29.8 years, respectively. About 47.6% of children were male. Statistically significant correlations between cord blood and childhood blood concentrations of Pb (r_Spearman =0.45; P = 0.04) and Mn (r_Pearson=0.48; P = 0.03) were found, and these remained significant when adjusted for the child's sex, age, or both. For Al and Hg, r_Spearman=0.29 and 0.08, respectively, but the correlations were not statistically significant (both P ≥ 0.20). A significant correlation between cord blood and childhood blood Pb concentrations for children 4-8 years old has not been previously reported.

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.

Measurement invariance of the Childhood Autism Rating Scale (CARS) across six countries

The Childhood Autism Rating Scale (CARS) is a simple and inexpensive tool for Autism spectrum disorder (ASD) assessments, with evidenced psychometric data from different countries. However, it is still unclear whether ASD symptoms are measured the same way across different societies and world regions with this tool, since data on its cross-cultural validity are lacking. This study evaluated the cross-cultural measurement invariance of the CARS among children with ASD from six countries, for whom data were aggregated from previous studies in India (n = 101), Jamaica (n = 139), Mexico (n = 72), Spain (n = 99), Turkey (n = 150), and the United States of America (n = 186). We analyzed the approximate measurement invariance based on Bayesian structural equation modeling. The model did not fit the data and its measurement invariance did not hold, with all items found non-invariant across the countries. Items related to social communication and interaction (i.e., relating to people, imitation, emotional response, and verbal and nonverbal communication) displayed lower levels of cross-country non-invariance compared to items about stereotyped behaviors/sensory sensitivity (i.e., body and object use, adaptation to change, or taste, smell, and touch response). This study found that the CARS may not provide cross-culturally valid ASD assessments. Thus, cross-cultural comparisons with the CARS should consider first which items operate differently across samples of interest, since its cross-cultural measurement non-invariance could be a source of cross-cultural variability in ASD presentations. Additional studies are needed before drawing valid recommendations in relation to the cultural sensitivity of particular items.

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.

Neonatal Outcome of Babies Born to Women 40 Years and Older in a Jamaican Birth Cohort

OBJECTIVE

 The study aimed to determine the outcome of babies born to women ≥40 years in a Jamaican birth cohort.

PATIENTS AND METHODS

 Maternal demographic data and neonatal data for women ≥40 years who delivered live singleton babies and their younger counterparts aged 20 30 years were extracted from the JA KIDS birth cohort dataset. Outcome measures were preterm birth, low birth weight, very low birth weight, extremely low birth weight, macrosomia, a low 5-minute Apgar score <7, admission to the neonatal unit, and neonatal death. Descriptive analyses were performed; statistical significance was taken at the level p <0.05.

RESULTS

 A total of 5,424 women and their babies were entered into the study, 5,099 (94%) women were aged 20 to 30 years (mean age ± standard deviation [SD]: 24.5 ± 3.2 years) and 325 (6%) were aged ≥40 years (mean age ± SD: 41.5 ± 1.6 years). A greater percentage of preterm babies (18%) were born to women ≥40 years than to their younger counterparts (14%; p = 0.04). There was no difference in the proportion of low birth weight infants, very low birth weight infants, or extremely low birth weight infants born between the two groups (p > 0.05). There was also no significant difference in the proportion of babies who were macrosomic and in those who had a low 5-minute Apgar score <7. There were 866 (16%) neonatal admissions, 67/325 (21%) of these babies were born to women aged ≥40 years and 799/5,099 (16%) were born to their younger counterparts (p = 0.01). The commonest reason for admission was prematurity. While 60 babies died, there was no significant difference between both groups with 56 (1%) born to women 20 to 30 years and 4 (1%) born to women ≥40 years (p = 0.48).

CONCLUSION

 Adverse outcomes noted for babies born to women ≥40 years were prematurity and the need for neonatal admission. However, no excess mortality was recorded.

KEY POINTS

· Women 40 years and older are more likely to have a chronic illness such as hypertension and diabetes and to have an operative delivery.. · Babies born to women 40 years and older are more likely to be late premature infants and require neonatal admission.. · However, there is no increased risk of neonatal mortality..

ECD - Pregnancy outcomes of a birth cohort. Are adolescent mothers really at more risk?

This sub-study within the JAKIDS longitudinal cohort study compares medical and psychosocial outcomes of pregnancy in younger adolescent mothers (<16 years), older adolescent mothers (16-19 years) and adult mothers (>19 years) in Jamaica. Participants were recruited from July to September 2011 and included 9521 mother-infant dyads; mean maternal age 26.0 years (SD 6.8). Adolescent mothers represented 19.1% (n = 1822) of the sample - 1704 older adolescent mothers (17.9%) and 118 younger adolescent mothers (1.2%). Participants completed interviewer-administered questionnaires regarding their sexual and reproductive health history, feelings about the current pregnancy, and presence of anxious and depressive symptoms. Data on delivery and perinatal and neonatal outcomes were extracted from hospital charts. Younger adolescent mothers were more likely to deliver preterm (p < 0.001) and low birth weight infants (p < 0.001) than older adolescent and adult mothers. Younger adolescent mothers had lower levels of antenatal anxiety regarding the pregnancy and its outcome (p < 0.001) while prevalence of elevated depressive symptoms antenatally (EPDS ≥11) was similar across age groups. Older adolescent mothers with significant depressive symptoms had increased odds of preterm delivery. These findings call for close antenatal monitoring of younger adolescent mothers and highlight the need for psychological services for all mothers.

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.

Accountability in protection of children against violence: Monitoring and measurement

Violence against children (VAC) is a pervasive and persistent injustice around the world. Thirty years after the adoption of the United Nations Convention on the Rights of the Child (CRC), the right of children to be protected against all forms of violence is still routinely violated. It is only within the last twenty years that the scope of this problem has been studied; as many point out, understanding the scope of the problem through comprehensive data collection is necessary to improve child protection. Data collection and data quality have improved drastically over this time. The Office of the High Commissioner on Human Rights recommends using comprehensive indicator systems that collect data on States Parties' structure- and process-related commitments to fulfil human rights, and on the outcomes of these commitments. However, most existing indicator sets on VAC fall short of this comprehensive approach, often focusing only on structural or outcome indicators. An international team of child rights experts is now developing GlobalChild, which will be an online platform consisting of comprehensive sets of structure-, process-, and outcome-related indicators for all 41 substantive rights of the CRC. This system will advance data collection, facilitate the monitoring function of the Committee on the Rights of the Child, and enable research on many rights of children, including their right to protection against violence. VAC is a complex problem, and protection against VAC is a right that is indivisible from other rights under the CRC. Therefore, a comprehensive and systematic approach is required to improve accountability to children around the world.

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.

Maternal morbidity: a longitudinal study of women's health during and up to 22 months after pregnancy in Jamaica

Our study evaluated factors associated with ill-health in a population-based longitudinal study of women who delivered a singleton live-born baby in a 3-month period across Jamaica. Socio-demographics, perception of health, chronic illnesses, frequency and reasons for hospital admission were assessed. Relationships between ill-health and maternal characteristics were estimated using log-normal regression analysis. Of 9,742 women interviewed at birth, 1,311 were assessed at four stages, 27.7% of whom reported ill-health at least once. Hospitalization rates were 20.9% during pregnancy, 6.1% up to 12 months and 0.5% up to 22 months after childbirth. Ill-health, reported by 11% of women, was less likely with better education (RR=0.62, 95%; 0.42-0.84). Hospital admission was associated with higher socio-economic status (RR=1.33, 95% 1.04-1.70) and Caesarean section [CS] (RR=1.57, 95%; 1.21-2.04). One in three (33.7%) women reported chronic illnesses, and the likelihood increased with age, parity and delivery by elective CS (RR=1.44, 95%; 1.20-1.73). In multivariable analyses, ill-health was more likely with chronic illness (RR=2.06, 95%; CI: 1.71-2.48) and hospital admission from 12 to 22 months after childbirth (RR=1.54, 95% CI: 1.12-2.12). Ill-health during pregnancy and after childbirth represent a significant burden of disease and requires a standardised comprehensive approach to measuring and addressing this disease burden.

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.

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.

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.

Patterns and predictors of depressive symptoms among Jamaican fathers of newborns

BACKGROUND

Approximately 10% of fathers in the Cultural West (i.e., US, Europe, and Australia) experience depression. We broaden the cultural scope of paternal depression research by investigating the prevalence and predictors of depressive symptoms among Jamaican fathers.

METHODS

The present research draws upon structured interviews with 3425 fathers of newborn children participating in a Jamaican birth cohort study-JA Kids-and represents one of the largest sample sizes of any study on postnatal depression among fathers worldwide. This sample of fathers participated from July to September 2011, and represents approximately 30% of all men who became fathers during that time in Jamaica. Fathers answered questions about sociodemographic background, relationship status and quality, social support, health, expectations and views of a partner's pregnancy, and the ten-item Edinburgh Postnatal Depression Scale (EPDS).

RESULTS

Analyses reveal that 9.1% (95% CI 8.1-10.1) of these Jamaican fathers of newborns had EPDS scores of 10 or higher, indicative of possible depression. Results suggest that educational attainment was not related to EPDS scores, though higher indices of material wealth (e.g., refrigerator and vehicle) were weakly, negatively related to EDS scores. Paternal age was also weakly negatively predictive of EDS scores. Whereas relationship status was unrelated to depressive symptoms, relationship quality negatively predicted depressive symptoms. Several other measures of social support (lacking a close circle of friends, fewer family, or friends to help in times of trouble) were also associated with higher EPDS scores.

CONCLUSIONS

We interpret these findings in light of existing work on paternal depression, including the importance of social context and support.

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 impact of polyvictimisation on children in LMICs: the case of Jamaica

Children who experience polyvictimization in high-income countries (HICs) are at higher risk for mental health-related trauma symptoms. There is limited information on the impact of polyvictimisation on children with high levels of exposure, as occurs in some low- and middle-income countries (LMICs). This study investigates the impact of poyvictimization on Jamaican children's intellectual functioning, achievement, and disruptive behaviors. Data from a geographical subgroup (n = 1171) of a 1986 population based birth cohort study were utilised.  At age 11-12 years, the sub-group completed questionnaires on exposure to violence at school, at home and in their communities, and tests of academic and intellectual functioning. Their parents completed questionnaires on family resources (socioeconomic status) and children's behaviour. Findings from Structural Equational Modelling indicated that for both genders, exposure to polyvictimisation had a direct negative effect on intellectual functioning, and an indirect negative effect on achievement mediated through intellectual functioning. For boys, polyvictimisation had a direct negative effect on behavioural risk. Family resources was negatively associated with exposure to polyvictimisation.  In Jamaica, a LMIC country with high levels of polyvictimisation, there is a significant negative effect of polyvictimisation on children. The secondary- and tertiary-level interventions to address these effects are costly to LMICs with limited financial resources. Prevention of exposure to violence in all its forms is therefore the recommended approach to reduce violence-related morbidity.

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.

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.

Early-life factors are associated with nocturnal cortisol and glucose effectiveness in Afro-Caribbean young adults

CONTEXT

Early-life factors (including intrauterine growth retardation) may influence the development of type 2 diabetes. We postulated that birth size is associated with cortisol levels, which itself could alter serum adipomyokines (i.e. adiponectin, IGF-I, myostatin) and glucose metabolism.

DESIGN

An observational study with 60 Afro-Caribbean young adults from a birth cohort.

MEASUREMENTS

Fasting blood was drawn for serum adiponectin, IGF-I and myostatin. A frequently sampled intravenous glucose tolerance test measured insulin sensitivity (SI), acute insulin response (AIRg), disposition index (DI) and glucose effectiveness (Sg). Body composition was assessed by dual-energy X-ray absorptiometry. Salivary cortisol was collected at home at 0800 and 2300 h. Sex-adjusted correlations were used to explore the relationships between birth size, cortisol and the metabolic variables.

RESULTS

The participants were 55% male, mean age 23·1 ± 0·5 years. Birth weight correlated positively with 2300-h cortisol (P = 0·04), although not after adjusting for gestational age. Gestational age was correlated with 2300 h cortisol (r = 0·38, P = 0·03), even after adjusting for birth weight (P = 0·02). 2300 h cortisol was not associated with adiponectin, IGF-I, myostatin, SI, AIRg or DI, but was negatively correlated with Sg (r = -0·30, P = 0·05) even after adjusting for birth and adult anthropometry. Adiponectin, IGF-I and myostatin were unrelated to glucose metabolism.

CONCLUSIONS

Gestational age is associated with higher nocturnal cortisol, which in turn is associated with lower glucose effectiveness in adulthood. Higher glucose effectiveness could therefore be a compensatory mechanism to improve glucose uptake.

Sexuality among fathers of newborns in Jamaica

BACKGROUND

While a growing body of research has addressed pregnancy and postpartum impacts on female sexuality, relatively little work has been focused upon men. A few studies suggest that a fraction of men report decreases in libido during a partner's pregnancy and/or postpartum, with alterations in men's sexual behavior also commonly aligning with those of a partner. Here, we investigate sexuality among fathers of newborn children in Jamaica. In Jamaica, as elsewhere in the Caribbean, relationship dynamics can be fluid, contributing to variable paternal roles and care, as well as a high fraction of children born into visiting relationships in which parents live apart from each other.

METHODS

During July-September, 2011, 3410 fathers of newborns with an average age of 31 (SD = 8) years participated in the fatherhood arm of a national birth cohort study (JAKids). These fathers answered questions about sociodemographic background, relationship quality and sexuality (e.g., various components of sexual function such as sex drive and sexual satisfaction as well as number of sexual partners the previous 12 months and sexual intercourse the previous week) during a visit to a hospital or birth center within a day or two of their child being born.

RESULTS

Showed that sex drive was more variable than other components (erections, ejaculation, problem assessment) of sexual function, though sexual satisfaction was generally high. Thirty percent of men reported two or more sexual partners the previous 12 months. Nearly half of men indicated not engaging in sexual intercourse the past week. Multivariate analyses showed that relationship status was related to various aspects of men's sexuality, such as men in visiting relationships reporting more sexual partners and more openness to casual sex. Relationship quality was the most consistent predictor of men's sexuality, with men in higher quality relationships reporting higher sexual satisfaction, fewer sexual partners, and higher frequency of sex, among other findings.

CONCLUSIONS

These results provide an unusually large, quantitative look at men's sexuality during the transition to fatherhood in Jamaica, offering helpful insight to would-be parents, clinicians or others seeking to anticipate the effects of a partner's pregnancy on men's sexuality.

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.

Blood lead concentrations in Jamaican children with and without autism spectrum disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder manifesting by early childhood. Lead is a toxic metal shown to cause neurodevelopmental disorders in children. Several studies have investigated the possible association between exposure to lead and ASD, but their findings are conflicting. Using data from 100 ASD cases (2–8 years of age) and their age- and sex-matched typically developing controls, we investigated the association between blood lead concentrations (BLC) and ASD in Jamaican children. We administered a questionnaire to assess demographic and socioeconomic information as well as exposure to potential lead sources. We used General Linear Models (GLM) to assess the association of BLC with ASD status as well as with sources of exposure to lead. In univariable GLM, we found a significant difference between geometric mean blood lead concentrations of ASD cases and controls (2.25 μg/dL cases vs. 2.73 μg/dL controls, p < 0.05). However, after controlling for potential confounders, there were no significant differences between adjusted geometric mean blood lead concentrations of ASD cases and controls (2.55 μg/dL vs. 2.72 μg/dL, p = 0.64). Our results do not support an association between BLC and ASD in Jamaican children. We have identified significant confounders when assessing an association between ASD and BLC.

Role of fruits, grains, and seafood consumption in blood cadmium concentrations of Jamaican children with and without Autism Spectrum Disorder

Human exposure to cadmium has adverse effects on the nervous system. Utilizing data from 110 age- and sex-matched case-control pairs (220 children) ages 2-8 years in Kingston, Jamaica, we compared the 75th percentile of blood cadmium concentrations in children with and without Autism Spectrum Disorder (ASD). In both univariable and multivariable Quantile Regression Models that controlled for potential confounding factors, we did not find any significant differences between ASD cases and typically developing (TD) controls with respect to the 75th percentile of blood cadmium concentrations, (P > 0.22). However, we found a significantly higher 75th percentile of blood cadmium concentrations in TD Jamaican children who consumed shellfish (lobsters, crabs) (P <0.05), fried plantain (P <0.01), and boiled dumpling (P <0.01). We also observed that children living in Jamaica have an arithmetic mean blood cadmium concentration of 0.16μg/L which is similar to that of the children in developed countries and much lower than that of children in developing countries. Although our results do not support an association between blood cadmium concentrations and ASD, to our knowledge, this study is the first to report levels of blood cadmium in TD children as well as those with ASD in Jamaica.

Blood manganese concentrations in Jamaican children with and without autism spectrum disorders

BACKGROUND

Manganese is an essential element for human health and development. Previous studies have shown neurotoxic effects in children exposed to higher levels of manganese. Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that impairs social interaction and communication. Several studies have hypothesized that ASD is caused through environmental exposures during crucial stages in brain development. We investigated the possible association between blood manganese concentrations (BMC) and ASD. We also identified factors associated with BMC in typically developing (TD) Jamaican children.

METHODS

We used data from 109 ASD cases with their 1:1 age- and sex-matched TD controls to compare mean BMC in Jamaican children (2-8 years of age) with and without ASD. We administered a pre-tested questionnaire to assess demographic and socioeconomic information, medical history, and potential exposure to manganese. Finally, we collected 2 mL of whole blood from each child for analysis of manganese levels. Using General Linear Models (GLM), we assessed the association between BMC and ASD status. Furthermore, we used two independent sample t-tests to identify factors associated with BMC in TD children.

RESULTS

In univariable GLM analysis, we found no significant association between BMC and ASD, (10.9 μg/L for cases vs. 10.5 μg/L for controls; P = 0.29). In a multivariable GLM adjusting for paternal age, parental education, place of child's birth (Kingston parish), consumption of root vegetables, cabbage, saltwater fish, and cakes/buns, there was still no significant association between BMC and ASD status, (11.5 μg/L for cases vs. 11.9 μg/L for controls; P = 0.48). Our findings also indicated TD children who ate fresh water fish had a higher BMC than children who did not (11.0 μg/L vs. 9.9 μg/L; P = 0.03) as younger TD children (i.e., 2 ≤ age ≤4), (12.0 μg/L vs. 10.2 μg/L; P = 0.01).

CONCLUSIONS

While these results cannot be used to assess early exposure at potentially more susceptible time period, our findings suggest that there is no significant association between manganese exposures and ASD case status in Jamaica. Our findings also indicate that BMC in Jamaican children resemble those of children in the developed world and are much lower than those in the developing countries.

Role of metabolic genes in blood arsenic concentrations of Jamaican children with and without autism spectrum disorder

Arsenic is a toxic metalloid with known adverse effects on human health. Glutathione-S-transferase (GST) genes, including GSTT1, GSTP1, and GSTM1, play a major role in detoxification and metabolism of xenobiotics. We investigated the association between GST genotypes and whole blood arsenic concentrations (BASC) in Jamaican children with and without autism spectrum disorder (ASD). We used data from 100 ASD cases and their 1:1 age- and sex-matched typically developing (TD) controls (age 2-8 years) from Jamaica. Using log-transformed BASC as the dependent variable in a General Linear Model, we observed a significant interaction between GSTP1 and ASD case status while controlling for several confounding variables. However, for GSTT1 and GSTM1 we did not observe any significant associations with BASC. Our findings indicate that TD children who had the Ile/Ile or Ile/Val genotype for GSTP1 had a significantly higher geometric mean BASC than those with genotype Val/Val (3.67 µg/L vs. 2.69 µg/L, p < 0.01). Although, among the ASD cases, this difference was not statistically significant, the direction of the observed difference was consistent with that of the TD control children. These findings suggest a possible role of GSTP1 in the detoxification of arsenic.

Seafood consumption and blood mercury concentrations in Jamaican children with and without autism spectrum disorders

Mercury is a toxic metal shown to have harmful effects on human health. Several studies have reported high blood mercury concentrations as a risk factor for autism spectrum disorders (ASDs), while other studies have reported no such association. The goal of this study was to investigate the association between blood mercury concentrations in children and ASDs. Moreover, we investigated the role of seafood consumption in relation to blood mercury concentrations in Jamaican children. Based on data for 65 sex- and age-matched pairs (2-8 years), we used a General Linear Model to test whether there is an association between blood mercury concentrations and ASDs. After controlling for the child's frequency of seafood consumption, maternal age, and parental education, we did not find a significant difference (P = 0.61) between blood mercury concentrations and ASDs. However, in both cases and control groups, children who ate certain types of seafood (i.e., salt water fish, sardine, or mackerel fish) had significantly higher (all P < 0.05) geometric means blood mercury concentration which were about 3.5 times that of children living in the US or Canada. Our findings also indicate that Jamaican children with parents who both had education up to high school are at a higher risk of exposure to mercury compared to children with at least one parent who had education beyond high school. Based on our findings, we recommend additional education to Jamaican parents regarding potential hazards of elevated blood mercury concentrations, and its association with seafood consumption and type of seafood.

Maternal and paternal age are jointly associated with childhood autism in Jamaica

Several studies have reported maternal and paternal age as risk factors for having a child with Autism Spectrum Disorder (ASD), yet the results remain inconsistent. We used data for 68 age- and sex-matched case-control pairs collected from Jamaica. Using Multivariate General Linear Models (MGLM) and controlling for parity, gestational age, and parental education, we found a significant (p < 0.0001) joint effect of parental ages on having children with ASD indicating an adjusted mean paternal age difference between cases and controls of [5.9 years; 95% CI (2.6, 9.1)] and a difference for maternal age of [6.5 years; 95% CI (4.0, 8.9)]. To avoid multicollinearity in logistic regression, we recommend joint modeling of parental ages as a vector of outcome variables using MGLM.

The role of drinking water sources, consumption of vegetables and seafood in relation to blood arsenic concentrations of Jamaican children with and without Autism Spectrum Disorders

Arsenic is a toxic metal with harmful effects on human health, particularly on cognitive function. Autism Spectrum Disorders (ASDs) are lifelong neurodevelopmental and behavioral disorders manifesting in infancy or early childhood. We used data from 130 children between 2 and 8 years (65 pairs of ASD cases with age- and sex-matched control), to compare the mean total blood arsenic concentrations in children with and without ASDs in Kingston, Jamaica. Based on univariable analysis, we observed a significant difference between ASD cases and controls (4.03 μg/L for cases vs. 4.48 μg/L for controls, P<0.01). In the final multivariable General Linear Model (GLM), after controlling for car ownership, maternal age, parental education levels, source of drinking water, consumption of "yam, sweet potato, or dasheen", "carrot or pumpkin", "callaloo, broccoli, or pak choi", cabbage, avocado, and the frequency of seafood consumption per week, we did not find a significant association between blood arsenic concentrations and ASD status (4.36 μg/L for cases vs. 4.65 μg/L for controls, P=0.23). Likewise, in a separate final multivariable GLM, we found that source of drinking water, eating avocado, and eating "callaloo, broccoli, or pak choi" was significantly associated with higher blood arsenic concentrations (all three P<0.05). Based on our findings, we recommend assessment of arsenic levels in water, fruits, and vegetables, as well as increased awareness among the Jamaican population regarding potential risks for various exposures to arsenic.

Prevalence of the metabolic syndrome and its components in relation to socioeconomic status among Jamaican young adults: a cross-sectional study

BACKGROUND

The metabolic syndrome has a high prevalence in many countries and has been associated with socioeconomic status (SES). This study aimed to estimate the prevalence of the metabolic syndrome and its components among Jamaican young adults and evaluate its association with parental SES.

METHODS

A subset of the participants from the 1986 Jamaica Birth Cohort was evaluated at ages 18-20 years between 2005 and 2007. Trained research nurses obtained blood pressure and anthropometric measurements and collected a venous blood sample for measurement of lipids and glucose. Prevalence of the metabolic syndrome and its components were estimated using the 2009 Consensus Criteria from the International Diabetes Federation, National Heart Lung and Blood Institute, American Heart Association, World Heart Federation, International Atherosclerosis Society, and International Association for the Study of Obesity. SES was assessed by questionnaire using occupation of household head, highest education of parent/guardian, and housing tenure of parent/guardian. Analysis yielded means and proportions for metabolic syndrome variables and covariates. Associations with levels of SES variables were obtained using analysis of variance. Multivariable analysis was conducted using logistic regression models.

RESULTS

Data from 839 participants (378 males; 461 females) were analyzed. Prevalence of the metabolic syndrome was 1.2% (95% confidence interval [95%CI] 0.5%-1.9%). Prevalence was higher in females (1.7% vs. 0.5%). Prevalence of the components [male: female] were: central obesity, 16.0% [5.3:24.7]; elevated blood pressure, 6.7% [10.8:3.3]; elevated glucose, 1.2% [2.1:0.4]; low HDL, 46.8% [28.8:61.6]; high triglycerides, 0.6% [0.5:0.6]. There were no significant differences in the prevalence of the metabolic syndrome for any of the SES measures used possibly due to lack of statistical power. Prevalence of central obesity was inversely associated with occupation (highly skilled 12.4%, skilled 13.5%, semi-skilled/unskilled 21.8%, p = 0.013) and education (tertiary 12.5%, secondary 14.1%, primary/all-age 28.4%, p = 0.002). In sex-specific multivariate logistic regression adjusted for hip circumference, central obesity remained associated with occupation and education for women only.

CONCLUSION

Prevalence of the metabolic syndrome is low, but central obesity and low HDL are present in 16% and 47% of Jamaican youth, respectively. Central obesity is inversely associated with occupation and education in females.

Perinatal factors in students admitted to the University of the West Indies data from the Jamaican Perinatal Study

OBJECTIVE

To compare perinatal and social factors in students admitted to The University of the West Indies (UWI), Kingston, Jamaica, at age 18 years with those in the rest of the Jamaican Perinatal Cohort.

METHOD

The Jamaican Perinatal Survey recorded demographic and perinatal details in 10 527 or 97% of births in Jamaica in September and October 1986. Eighteen years later 140 of these were admitted to the UWI in Kingston, Jamaica. The perinatal features of these UWI students have been compared with the rest of the Perinatal Survey Cohort.

RESULTS

Mothers of UWI students were older (p < 0.001), more likely to be married at the time of birth (p < 0.001), had earlier and more complete antenatal care (p < 0.05) and greater educational achievement at time of pregnancy (p < 0.001). These mothers of UWI students were also more likely to have diabetes (p < 0.01), operative deliveries (p < 0.01) and to attend private hospitals (p < 0.01). The UWI students had fewer siblings by their mothers (p < 0.05), were less likely to be low birthweight babies (p = 0.035) and more likely to be full-term (37-42 weeks) than lower gestational age (p = 0.005). Differences in Apgar scores did not reach statistical significance.

CONCLUSIONS

The students of the University of the West Indies were more likely to come from smaller families with features indicative of a better quality of life. They were also of higher birthweight and tended to be full-term. The lack of association of Apgar scores with educational attainment is noteworthy.

Impact of the Jamaican birth cohort study on maternal, child and adolescent health policy and practice

The Jamaica Perinatal Morbidity and Mortality Survey (JPMMS) was a national study designed to identify modifiable risk factors associated with poor maternal and perinatal outcome. Needing to better understand factors that promote or retard child development, behaviour and academic achievement, we conducted follow-up studies of the birth cohort. The paper describes the policy developments from the JPMMS and two follow-up rounds. The initial study (1986-87) documented 94% of all births and their outcomes on the island over 2 months (n = 10 508), and perinatal (n = 2175) and maternal deaths (n = 62) for a further 10 months. A subset of the birth cohort, identified by their date of birth through school records, was seen at ages 11-12 (n = 1715) and 15-16 years (n = 1563). Findings from the initial survey led to, inter alia, clinic-based screening for syphilis, referral high-risk clinics run by visiting obstetricians, and the redesign and construction of new labour wards at referral hospitals. The follow-up studies documented inadequate academic achievement among boys and children attending public schools, and associations between under- and over-nutrition, excessive television viewing (>20 h/week), inadequate parental supervision and behavioural problems. These contributed to the development of a television programming code for children, a National Parenting Policy, policies aimed at improving inter-sectoral services to children from birth to 5 years (Early Childhood Commission) and behavioural interventions of the Violence Prevention Alliance (an inter-sectoral NGO) and the Healthy Lifestyles project (Ministry of Health). Indigenous maternal and child health research provided a local evidence base that informed public policy. Collaboration, good communication, being vigilant to opportunities to influence policy, and patience has contributed to our success.

Interpersonal violence in three Caribbean countries: Barbados, Jamaica, and Trinidad and Tobago

OBJECTIVES

This article reports the prevalence of two types of interpersonal violence (IPV) (sexual and physical) and one type of aggression (psychological) in three low-to-middle-income Caribbean countries. It examines IPV among adolescents and young adults as both victims and perpetrators.

METHOD

This population-based study compares the experiences of 15-30 year olds in countries at different levels of socioeconomic development. The Revised Conflict Tactics Scales (CTS2) and other behavioral instruments were used to assess the level and characteristics of IPV.

RESULTS

Out of 3 401 respondents, 70.9% reported victimization by some form of violence, which was most commonly perpetrated by a relationship partner (62.8%). Sexual violence victimization was reported more commonly by women, and was highest in Jamaica. Significant between-country differences in overall levels of reported physical violence, and psychological aggression, were evident when stratifying by perpetrator type.

CONCLUSIONS

The very high levels of reported IPV indicate very high levels of tolerance among victims, and suggest a culture of violence and of adversarial intimate relationships may be well entrenched. The findings support the view that co-occurrence of general interpersonal violence and partner violence may be limited, and that one may not necessarily be a predictor of the other. They also reveal that, among partners, not only are there no gender differentials in victimization by physical violence, but more women than men are self-reporting as perpetrators of this type of IPV.

Comprehensive longitudinal studies of child health, development and behaviour in Jamaica: findings and policy impact

BACKGROUND

Birth cohort and other longitudinal studies of children's health, development and behaviour have provided important information on child and adult outcomes. This has allowed evidence based policy and programme development targeted at issues specific to countries. Few studies have been conducted in developing countries. This paper reports on the findings and policy implications of two comprehensive longitudinal studies in Jamaica.

METHOD

The findings of the Jamaican Birth Cohort Studies, conducted between 1986 and 2003, and the Profiles Project, a longitudinal study commencing in 1999 when children were six years, were reviewed. Recommendations from the studies and their impact on policy and programme development for Jamaican children were identified.

RESULTS

Policy and programme impact were identified in areas of child poverty intervention, parenting, social activities, violence and aggression, health and nutrition, screening and early intervention, setting of standards for early childhood institutions, gender early childhood indicators and education and training. Policy and programme impact were national, regional and international.

CONCLUSION

Comprehensive longitudinal studies of children in developing countries, though costly, provide wide-ranging and important information for policy and programme development.

Mortality of very-low-birth-weight infants in Jamaica

A 10-year retrospective descriptive study was conducted looking at the outcome of all neonates weighing less than 1500 g admitted to the University Hospital of the West Indies. Analysis of predictors of mortality using regression models revealed birth weight to be the only independent predictor of mortality. Further improvement in survival of these infants will be dependent on the availability of ventilatory and nutritional support.

Growth curves for normal Jamaican Neonates

The aim of this study was to provide standards for the assessment of birthweight, head circumference and crown-heel length for normal, singleton newborns of predominantly West African descent. Data were collected for 10 482 or 94% of all recorded births in Jamaica during the two-month period September 1 to October 31, 1986. After editing procedures, data were available for 6178 (birthweight), 5975 (head circumference), and 5990 (crown-heel length). The data presented in tables and growth curves include birthweight, head circumference and crown-heel length for males and females separately, for gestational ages 30-43 weeks. Data sets from the University Hospital of the West Indies in 1990 and 1999 were used to explore the possibility of secular change over the period 1986-1999. In conclusion, these ethnic and gender-specific growth curves are based on the most extensive dataset currently available in Jamaica for babies of West African descent.

Are oral contraceptive use and pregnancy complications risk factors for atopic disorders among offspring?

In utero programming of atopic manifestations has been suggested. We investigated the association between oral contraceptive (OC) use before, and complications during pregnancy (CDP) and asthma, along with other atopic manifestations. The study is based on neonates from Kingston and St Andrew, a geographic subcohort from the Jamaican Perinatal Morbidity, Mortality Survey conducted in 1986-1987. Information on OC use and CDP was extracted from maternal interviews and medical records. In a follow up in 1997-1998, via interviews with mothers, trained nurses collected information on asthma/wheezing, coughing, eczema, and hay fever. Data, specific to this paper, from birth and 11-12 yr of age was available for a total of 1040 of the 1720 members of the geographic subcohort. Using logistic regression, controlling for confounders, we estimated adjusted odds ratio (aOR) and corresponding 95% confidence intervals (CI). For asthma or wheezing, and coughing, aOR for OC use were 1.81 (95% CI: 1.25-2.61), and 2.72 (95% CI: 1.41-5.24), respectively. CDP was only shown to be a significant risk factor for hay fever. Additionally, a higher number of older siblings were protective for hay fever. The results suggest that asthma in childhood may be programmed in utero.

Paediatric HIV/AIDS in Jamaica. A hospital-based description

The continuing worldwide epidemic of adult HIV/AIDS has led to an increase in the number of HIV-positive children mainly through perinatal transmission. Although national data are available, there is no published report of the epidemiology of HIV/AIDS in children in Jamaica. A multicentre retrospective analysis of 183 HIV seropositive children admitted to hospitals in Jamaica between 1990 and 1996 was conducted. Ages at diagnosis were available for 172 patients with 61% diagnosed in the first year of life. Clinical histories were available for 129 patients with the primary presenting symptoms of infected children being failure to thrive, pneumonia, diarrhoea, dermatitis and lymphadenopathy. Classification was possible in 128 patients: 49 were exposed, 76 were infected and three were seroreverters. Infected children had a longer hospital stay than those classified as exposed or seroreverters. As of December 31, 1997, 125 patients had defaulted, nine patients were alive and 51 were reported dead with a median age of death of 12 months. From these data, it is estimated that the hospital-based HIV incidence among children in Jamaica increased from 0.149 per 10,000 person years in 1990 to 1.331 per 10,000 person years in 1996. This study demonstrates a rise in the estimated incidence of HIV/AIDS but we were unable to estimate survival reliably since the data required were not available for 75% of children identified. These data highlight the urgent need for targeted interventions to reduce vertical transmission of HIV as well as a need for prospective studies to establish reliable data on incidence and long-term outcome for HIV-infected children.