Katherine Loveland - Academia.edu (original) (raw)
Papers by Katherine Loveland
American journal of mental retardation : AJMR, 1995
Changes in functioning related to aging were examined in 34 adults (14 females, 20 males) with Do... more Changes in functioning related to aging were examined in 34 adults (14 females, 20 males) with Down syndrome who were 22 to 56 years of age. Changes in functioning over 3 to 4 years were examined, with age, IQ at entry into the study, and gender considered. Neither effects of age at entry nor change over time were significant, suggesting that changes related to aging in adults with Down syndrome were minimal. In contrast, IQ at entry had a significant effect on all performances, suggesting that any examination of aging must consider intellectual level. Results do not support the idea that adults with Down syndrome show rapid age-related declines in functioning apart from the occurrence of a progressive dementia such as Alzheimer's disease.
Journal of Autism and Developmental Disorders, 1986
The relationship of gestural joint attention behaviors and the development of effective communica... more The relationship of gestural joint attention behaviors and the development of effective communication skills in autism and developmental language delay (DLD) was investigated. Autistic and DLD children matched for MA and MLU were compared on measures of gestural joint attention behavior, personal pronoun use, and spontaneous communicative behavior. DLD children responded correctly to joint attention interactions more often than autistic children, and their spontaneous gestural behavior was more communicative and developmentally advanced. Correct production of "I/you" pronouns was related to number of spontaneous initiations for autistic but not for DLD children. Measures of spontaneous joint attention behaviors were in general not related to MA, CA, or MLU for either group. DLD children's performance suggests no special impairment of joint attention skills, whereas autistic children's performance suggests a joint attention deficit in addition to a language deficit.
American Journal of Psychiatry, 2001
An estimated 5.4 million people in the United States diagnosed with Alzheimer's disease or relate... more An estimated 5.4 million people in the United States diagnosed with Alzheimer's disease or related disorders (ADRD) receive about $210 billion worth of unpaid care annually fro m about 15 million loved ones. As these numbers grow, the urgency builds to discover causes, treatments, and cures. Ever searching for pro mising, effective, and less expensive treatments, family caregivers are eager to adopt treatments, promoted strongly in the media. Coconut oil, especially virgin coconut oil, has starred in recent years in several internet and newspaper anecdotes as providing significant cognitive improvements in people with ADRD. A co mprehensive literature review found only two studies examining the impact of coconut oil in hu mans though neither study dealt with ADRD. Research on dementia leading to diminishing cerebral glucose metabolism has reported on the benefit of ketone food. More controlled research is needed about the value of ketone foods, such as the varieties of coconut oil and MCT Oil. Though well researched the FDA-regulated (2009) ketone-medical-food Axona® wh ich contains some coconut oil ingredients has shown evidence of cognitive improvements in people with mild to moderate Alzheimer's disease but more research is needed to clarify individual sensitivities, side effects, and health risks such as acidosis or hypocalcemia, possible with long-term use by people with ADRD.
Genes
Glutathione S-transferases (GST) are involved in the detoxification of exogenous chemicals includ... more Glutathione S-transferases (GST) are involved in the detoxification of exogenous chemicals including lead (Pb). Using data from 344 pairs of autism spectrum disorder (ASD) cases and age- and sex-matched typically developing (TD) controls (2–8 years old) from Jamaica, we investigated the interaction between three GST genes and ASD status as determinants of blood Pb concentrations (BPbCs). We found that ASD cases had lower geometric mean BPbCs than TD children (1.74 vs. 2.27 µg/dL, p < 0.01). Using a co-dominant genetic model, ASD cases with the Ile/Val genotype for the GSTP1 Ile105Val polymorphism had lower GM BPbCs than TD controls, after adjusting for a known interaction between GSTP1 and GSTT1, child’s parish, socioeconomic status, consumption of lettuce, fried plantains, and canned fish (Ile/Val: 1.78 vs. 2.13 µg/dL, p = 0.03). Similarly, among carriers of the I/I or I/D (I*) genotype for GSTT1 and GSTM1, ASD cases had lower adjusted GM BPbCs than TD controls (GSTT1 I*: 1.61 v...
Journal of Environmental Science and Health, Part A, 2021
Challenges to the development of the next generation of selfreporting cardiovascular implantable ... more Challenges to the development of the next generation of selfreporting cardiovascular implantable medical devices.
Research in Autism Spectrum Disorders, 2020
Background Exposure to many environmental chemicals, including metals, often does not occur in is... more 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.
Journal of Autism and Developmental Disorders, 2020
Using data from 266 age- and sex-matched pairs of Jamaican children with autism spectrum disorder... more 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.
Journal of Autism and Developmental Disorders, 2019
Conflict of Interest: Sepideh Saroukhani declares that she has no conflict of interest. Maureen S... more Conflict of Interest: Sepideh Saroukhani declares that she has no conflict of interest. Maureen Samms-Vaughan declares that she has no conflict of interest. MinJae Lee declares that she has no conflict of interest. MacKinsey A. Bach declares that she has no conflict of interest. Jan Bressler declares that she has no conflict of interest. Manouchehr Hessabi declares that he has no conflict of interest. Megan L. Grove declares that she has no conflict of interest. Sydonnie Shakespeare-Pellington declares that she has no conflict of interest. Katherine A. Loveland declares that she has no conflict of interest. Mohammad H. Rahbar declares that he has no conflict of interest. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.
Research in Autism Spectrum Disorders, 2018
Background: We previously reported a significant interactive association between polymorphisms of... more 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 ≥ 12 μg/L
International Journal of Environmental Research and Public Health, 2015
The objective of this study was to characterize the concentrations of lead, mercury, cadmium, alu... more 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 socioeconomic 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.
Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering, Jan 12, 2015
Lead is a heavy metal known to be detrimental to neurologic, physiologic, and behavioral health o... more 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 concentr...
Research in Autism Spectrum Disorders, 2014
Research in Autism Spectrum Disorders, 2015
Research in Autism Spectrum Disorders, 2014
Archives of General Psychiatry, 2002
Klein's assumption was that D-lactate could not be metabolized by humans, and he drew th... more Klein's assumption was that D-lactate could not be metabolized by humans, and he drew the conclusion from his findings that theories of lactate-induced panic requiring metabolism of the lactate were invalid. There was at the time a considerable literature demonstrating that D-lactate is metabolized by humans, 3-5 and this has grown6 with the confirmation that enzymes required for this are present in humans. 7 Additionally, the data presented by the Columbia Group2 are indicative that D-lactate was being metabolized by their subjects. ...
International Journal of Environmental Research and Public Health, 2014
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder manifesting by early childhood. L... more 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.
Science of The Total Environment, 2012
Arsenic is a toxic metal with harmful effects on human health, particularly on cognitive function... more 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 2-8 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 (4.03μg/L for cases vs. 4.48μg/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
Journal of the American Academy of Child & Adolescent Psychiatry, 2004
Objective: Cognitive effects of stimulant medication were investigated in children with mental re... more Objective: Cognitive effects of stimulant medication were investigated in children with mental retardation (MR) and attention-deficit/hyperactivity disorder (ADHD). Method: Performance on tasks tapping sustained attention, visual and auditory selective attention, inhibition, and immediate memory was assessed for 24 children (mean age 10.9 years) during a placebo-controlled, double-blind, crossover treatment trial with 0.15, 0.30, and 0.60 mg/kg b.i.d. dosages of methylphenidate (MPH). Results: Successively higher MPH doses were associated with consistent gains in cognitive task performance, with optimal performance noted at the highest dose. Analysis of dose-response curves revealed significant linear components of trend on measures tapping sustained attention, visual selective attention, auditory selective attention, as well as two tasks tapping inhibition/impulsivity: delay of gratification and match-to-sample. No evidence of a curvilinear dose-response relationship emerged for any measure. Conclusions: Inattention and disinhibition/impulsivity decline with MPH treatment in children with ADHD/MR, and consistent with the Multimodal Treatment Study of ADHD, higher MPH doses are most effective. These findings also suggest that cognitive testing, together with behavioral and medical assessment, can be an effective tool in assessing stimulant response in children with ADHD/MR.
Journal of Autism and Developmental Disorders, 2012
Several studies have reported maternal and paternal age as risk factors for having a child with A... more 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 ageand 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.
American journal of mental retardation : AJMR, 1995
Changes in functioning related to aging were examined in 34 adults (14 females, 20 males) with Do... more Changes in functioning related to aging were examined in 34 adults (14 females, 20 males) with Down syndrome who were 22 to 56 years of age. Changes in functioning over 3 to 4 years were examined, with age, IQ at entry into the study, and gender considered. Neither effects of age at entry nor change over time were significant, suggesting that changes related to aging in adults with Down syndrome were minimal. In contrast, IQ at entry had a significant effect on all performances, suggesting that any examination of aging must consider intellectual level. Results do not support the idea that adults with Down syndrome show rapid age-related declines in functioning apart from the occurrence of a progressive dementia such as Alzheimer's disease.
Journal of Autism and Developmental Disorders, 1986
The relationship of gestural joint attention behaviors and the development of effective communica... more The relationship of gestural joint attention behaviors and the development of effective communication skills in autism and developmental language delay (DLD) was investigated. Autistic and DLD children matched for MA and MLU were compared on measures of gestural joint attention behavior, personal pronoun use, and spontaneous communicative behavior. DLD children responded correctly to joint attention interactions more often than autistic children, and their spontaneous gestural behavior was more communicative and developmentally advanced. Correct production of "I/you" pronouns was related to number of spontaneous initiations for autistic but not for DLD children. Measures of spontaneous joint attention behaviors were in general not related to MA, CA, or MLU for either group. DLD children's performance suggests no special impairment of joint attention skills, whereas autistic children's performance suggests a joint attention deficit in addition to a language deficit.
American Journal of Psychiatry, 2001
An estimated 5.4 million people in the United States diagnosed with Alzheimer's disease or relate... more An estimated 5.4 million people in the United States diagnosed with Alzheimer's disease or related disorders (ADRD) receive about $210 billion worth of unpaid care annually fro m about 15 million loved ones. As these numbers grow, the urgency builds to discover causes, treatments, and cures. Ever searching for pro mising, effective, and less expensive treatments, family caregivers are eager to adopt treatments, promoted strongly in the media. Coconut oil, especially virgin coconut oil, has starred in recent years in several internet and newspaper anecdotes as providing significant cognitive improvements in people with ADRD. A co mprehensive literature review found only two studies examining the impact of coconut oil in hu mans though neither study dealt with ADRD. Research on dementia leading to diminishing cerebral glucose metabolism has reported on the benefit of ketone food. More controlled research is needed about the value of ketone foods, such as the varieties of coconut oil and MCT Oil. Though well researched the FDA-regulated (2009) ketone-medical-food Axona® wh ich contains some coconut oil ingredients has shown evidence of cognitive improvements in people with mild to moderate Alzheimer's disease but more research is needed to clarify individual sensitivities, side effects, and health risks such as acidosis or hypocalcemia, possible with long-term use by people with ADRD.
Genes
Glutathione S-transferases (GST) are involved in the detoxification of exogenous chemicals includ... more Glutathione S-transferases (GST) are involved in the detoxification of exogenous chemicals including lead (Pb). Using data from 344 pairs of autism spectrum disorder (ASD) cases and age- and sex-matched typically developing (TD) controls (2–8 years old) from Jamaica, we investigated the interaction between three GST genes and ASD status as determinants of blood Pb concentrations (BPbCs). We found that ASD cases had lower geometric mean BPbCs than TD children (1.74 vs. 2.27 µg/dL, p < 0.01). Using a co-dominant genetic model, ASD cases with the Ile/Val genotype for the GSTP1 Ile105Val polymorphism had lower GM BPbCs than TD controls, after adjusting for a known interaction between GSTP1 and GSTT1, child’s parish, socioeconomic status, consumption of lettuce, fried plantains, and canned fish (Ile/Val: 1.78 vs. 2.13 µg/dL, p = 0.03). Similarly, among carriers of the I/I or I/D (I*) genotype for GSTT1 and GSTM1, ASD cases had lower adjusted GM BPbCs than TD controls (GSTT1 I*: 1.61 v...
Journal of Environmental Science and Health, Part A, 2021
Challenges to the development of the next generation of selfreporting cardiovascular implantable ... more Challenges to the development of the next generation of selfreporting cardiovascular implantable medical devices.
Research in Autism Spectrum Disorders, 2020
Background Exposure to many environmental chemicals, including metals, often does not occur in is... more 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.
Journal of Autism and Developmental Disorders, 2020
Using data from 266 age- and sex-matched pairs of Jamaican children with autism spectrum disorder... more 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.
Journal of Autism and Developmental Disorders, 2019
Conflict of Interest: Sepideh Saroukhani declares that she has no conflict of interest. Maureen S... more Conflict of Interest: Sepideh Saroukhani declares that she has no conflict of interest. Maureen Samms-Vaughan declares that she has no conflict of interest. MinJae Lee declares that she has no conflict of interest. MacKinsey A. Bach declares that she has no conflict of interest. Jan Bressler declares that she has no conflict of interest. Manouchehr Hessabi declares that he has no conflict of interest. Megan L. Grove declares that she has no conflict of interest. Sydonnie Shakespeare-Pellington declares that she has no conflict of interest. Katherine A. Loveland declares that she has no conflict of interest. Mohammad H. Rahbar declares that he has no conflict of interest. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.
Research in Autism Spectrum Disorders, 2018
Background: We previously reported a significant interactive association between polymorphisms of... more 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 ≥ 12 μg/L
International Journal of Environmental Research and Public Health, 2015
The objective of this study was to characterize the concentrations of lead, mercury, cadmium, alu... more 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 socioeconomic 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.
Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering, Jan 12, 2015
Lead is a heavy metal known to be detrimental to neurologic, physiologic, and behavioral health o... more 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 concentr...
Research in Autism Spectrum Disorders, 2014
Research in Autism Spectrum Disorders, 2015
Research in Autism Spectrum Disorders, 2014
Archives of General Psychiatry, 2002
Klein's assumption was that D-lactate could not be metabolized by humans, and he drew th... more Klein's assumption was that D-lactate could not be metabolized by humans, and he drew the conclusion from his findings that theories of lactate-induced panic requiring metabolism of the lactate were invalid. There was at the time a considerable literature demonstrating that D-lactate is metabolized by humans, 3-5 and this has grown6 with the confirmation that enzymes required for this are present in humans. 7 Additionally, the data presented by the Columbia Group2 are indicative that D-lactate was being metabolized by their subjects. ...
International Journal of Environmental Research and Public Health, 2014
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder manifesting by early childhood. L... more 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.
Science of The Total Environment, 2012
Arsenic is a toxic metal with harmful effects on human health, particularly on cognitive function... more 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 2-8 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 (4.03μg/L for cases vs. 4.48μg/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
Journal of the American Academy of Child & Adolescent Psychiatry, 2004
Objective: Cognitive effects of stimulant medication were investigated in children with mental re... more Objective: Cognitive effects of stimulant medication were investigated in children with mental retardation (MR) and attention-deficit/hyperactivity disorder (ADHD). Method: Performance on tasks tapping sustained attention, visual and auditory selective attention, inhibition, and immediate memory was assessed for 24 children (mean age 10.9 years) during a placebo-controlled, double-blind, crossover treatment trial with 0.15, 0.30, and 0.60 mg/kg b.i.d. dosages of methylphenidate (MPH). Results: Successively higher MPH doses were associated with consistent gains in cognitive task performance, with optimal performance noted at the highest dose. Analysis of dose-response curves revealed significant linear components of trend on measures tapping sustained attention, visual selective attention, auditory selective attention, as well as two tasks tapping inhibition/impulsivity: delay of gratification and match-to-sample. No evidence of a curvilinear dose-response relationship emerged for any measure. Conclusions: Inattention and disinhibition/impulsivity decline with MPH treatment in children with ADHD/MR, and consistent with the Multimodal Treatment Study of ADHD, higher MPH doses are most effective. These findings also suggest that cognitive testing, together with behavioral and medical assessment, can be an effective tool in assessing stimulant response in children with ADHD/MR.
Journal of Autism and Developmental Disorders, 2012
Several studies have reported maternal and paternal age as risk factors for having a child with A... more 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 ageand 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.