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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Blood copper, zinc, magnesium and lead levels were determined by atomic absorption spectroscopy for 15 males and 16 females suffering from depression, 6 males and 1 female with mental retardation and 3 males and 4 females with seizure disorders. They were all under no medication and belonged to low income groups. No difference in copper levels was found between the sexes in any of the groups. The levels in all the groups were significantly higher than in the normals. In depressives, males had significantly higher zinc levels than females and only female depressives had significantly different (lower) levels from normals. In both depressives and normals, males had higher magnesium levels than females but no group of patients had significantly different levels from normals. Lead levels were significantly higher in female depressives and for those with seizure disorders than for controls. At least one metal abnormality was found in 21 (67.7%) depressive, 5 (71.4%) of those with mental retardation and 6 (85.7%) with seizure disorders.
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PMID:Trace element studies on Karachi population. Part IV: Blood copper, zinc, magnesium and lead levels in psychiatric patients with depression, mental retardation and seizure disorders. 251 24

The metal magnesium and the trace elements lead, lithium, copper, and zinc were determined by atomic absorption spectrophotometry in the plasma of 107 residents with different types of mental retardation at a state institution in Minnesota. Twenty-six staff volunteers and 29 residents with psychosocial mental retardation served as control subjects. Plasma magnesium concentrations were normal in all retarded subjects. Lead and lithium concentrations were below detection levels in all retarded and nonretarded subjects. Low copper concentrations were found in the plasma of retarded dwarfs and of male microcephalic subjects. The most significant finding was hypozincemia in 49 subjects with Down syndrome of both sexes and all ages. Because this finding was limited to residents with Down syndrome, a nutritional deficiency is most unlikely. The possible etiological factors of hypozincemia in Down syndrome were discussed.
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PMID:Plasma concentrations of magnesium, lead, lithium, copper, and zinc in mentally retarded persons. 295 83

In the 40 years from 1950 to 1990, lead epidemiology and public policy based on it made enormous strides. Exposure levels that caused concern in the medical and public health community fell from 80 to 10 micrograms/dL of blood. In the space of 20 years, beginning in 1970, first the surgeon general and then the CDC lowered the official "level of concern" from 50 or 60 to 10 micrograms/dL. The public health community has turned its attention from the prevention of poisoning that results in encephalopathy, mental retardation, and death to the reduction of exposure to avoid subtle neurobehavioral deficits that are detectable only in fairly large epidemiological studies. Numerous advances in technology and analysis have facilitated progress in lead epidemiology. In order to show that intellectual deficits were related to lead exposure rather than to such confounding variables as parental education, parental IQ, income, or parents' age at time of birth, researchers performed extensive regression analyses of fairly large sample populations, controlling for as many as 39 confounding variables. These analyses would have been virtually impossible but for the development of computer software programs that became available beginning in the late 1960s and early 1970s. Handling of large data bases, such as NHANES II, also required access to computer hardware and software not generally available earlier. The existence of the data depended on other technological innovations that made screening of large populations inexpensive and relatively simple. In 1973, erythrocyte protoporphyrin screening transformed testing for lead poisoning. With the advent of atomic absorption spectroscopy and rapid improvement in equipment for blood lead analysis, obtaining blood lead levels became less expensive and easier and produced more accurate results. Increasing attention both to preventing environmental contamination of samples and to controlling laboratory quality also improved the accuracy of data collected. Advances in screening and analytical technology made the mass screening of the 1970s possible--both the programs coordinated by the CDC and NHANES II. NHANES II showed the extent of the problem of lead exposure to be even greater than previously thought. It was estimated that in 1980 almost 2 percent of all children aged six months to five years had blood lead levels over the CDC level of concern of 30 micrograms/dL. More than 13 percent of black children had levels above 30 micrograms/dL. Lead was certainly the most widespread threat to child health in America. In 1985, when the CDC lowered the level of concern to 25 micrograms/dL, the population defined to be at risk tripled.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Round and round it goes: the epidemiology of childhood lead poisoning, 1950-1990. 845 Aug 21

Developmental toxicants, insidious in modes of action and effects, strike the very origin of our lives: the developing embryo, fetus, neonate, and child; they cause spontaneous abortions, stillbirths, malformations, early postnatal mortality, reduced birth weight, mental retardation, sensory loss as well as other functional or physical changes, including subclinical effects having far reaching social and economic impacts. The large majority of developmental defects have unknown etiologies. With this uncertainty, EPA and the scientific community world-wide give high priority to finding new approaches for assessing etiology and risks of developmental effects. The United Nations Conference on Environment and Development (UNCED) and Agenda 21 mobilized the international community to focus on risks posed by chemicals in the environment, including developmental risks. The international harmonization of test and risk assessment guidelines for developmental effects are priorities. Lead, persistent organic pollutants (POPs), endocrine disruptors, and the improvement of quantitative risk assessment methodologies, particularly for children, are priorities. EPA reinvented its research agenda of assure wide involvement of the National Science Foundation, other federal agencies, and national experts in research to address the U.S.'s public health and environmental priorities.
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PMID:New approaches for assessing the etiology and risks of developmental abnormalities from chemical exposure. 910 Mar 20

Lead exposure even at low levels has adverse effects for the central nervous system (CNS), but pregnant women, neonates, lactating infants, and preschool and school age children are most susceptible to it. In rats anatomical alterations included swelling in the mitochondria of renal duct cells (at 26 mcg/dl); biochemical effects involved marked reduction of cytochrome content in the cerebral cortex (36 mcg/dl); and physiological effects were induced at the level of 30-50 mcg/dl. Central nervous system effects entailed persistent decrease of visual acuity (65 mcg/dl at birth and 7 mcg/dl 90 days later), the increase of the latency of primary and secondary components of evoked visual responses during the prenatal and adult period (65 mcg/dl and 7 mcg/dl on days 21 and 90 after birth, respectively). 30 and even 20 mcg/dl of lead in the blood produced nerve conductivity deficits. A study of 425 children with lead poisoning showed a 39% rate of mental retardation and convulsions impervious to treatment. Lead levels within a range of 10-25 mcg/dl reduced the score on the mental development inventory by 4-8 points. The population of the Valley of Mexico numbers 15-20 million with 50% of Mexico's industry. A who investigation indicated blood levels of an average of 22.5 mcg/dl in a group of school teachers, the highest in 10 major population centers in the world. Blood levels in 405 pregnant women in Mexico City averaged 20.3 mcg/dl, and the sample from the umbilical cord of fetuses showed 13.6 mcg/dl. Another study disclosed blood levels of 16 mcg/dl in mothers and 13 mcg/dl in their offspring. The most probable sources of lead are: leaded gasoline, secondary recapture of lead for making batteries, use of paints, ceramics used for storing and cooking food, lead seal of milk containers, and consumption of food contaminated with lead.
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PMID:[Evaluation of the potential risk of perinatal exposure to lead in the Valle de Mexico]. 1228 39

Lead poses a serious environmental health risk to young children, causing such irreversible health effects as mental retardation, stunted growth, and hearing and visual impairment. Studies suggest that various sectors of the public, including children's caregivers, are not sufficiently concerned about this risk or knowledgeable about ways of minimizing it. Because newspapers are one of the primary ways members of the public learn about risks, the authors examined the characteristics and content of 152 newspaper articles on lead to determine when coverage occurred and what information was provided. Results revealed that newspapers most often covered lead as a local news story. Few articles identified children under six years of age as the most vulnerable group or provided important information on health effects, sources of exposure, or abatement methods. The authors' recommendations focus on helping environmental health professionals work with newspaper journalists to improve the information available to the public.
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PMID:Do newspapers lead with lead? A content analysis of how lead health risks to children are covered. 1280 Aug 16

Lead poisoning affects an estimated 890,000 young children in the United States annually (American Academy of Pediatrics [AAP], 1998). Extremely high levels in the child can cause mental retardation, coma, seizures, and death. Chronic low level exposure is more commonly seen with multiple effects, including learning disabilities, impaired growth, and hearing loss. Lead poisoning prevention efforts have significantly reduced the number of children affected by this serious health hazard. Health care providers need to continue their vigilant efforts to educate families living in older homes about the risks, screening, and treatment.
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PMID:Lead poisoning: a summary of treatment and prevention. 1296 48

In one study of children in 27 families with maternal retardation, those children with higher intelligence quotient (IQ) were more likely to have multiple behavior problems than those with lower IQ. If true, this result would affect clinical practice, but it has not been replicated. Because the setting of the initial observation is similar to the setting of childhood lead poisoning, we attempted a replication using data from the Treatment of Lead-Exposed Children (TLC) study, in which 780 children aged 12-33 mo with blood lead levels 20-44 microg/dL were randomized to either succimer treatment or placebo and then followed up to 5 y. Of 656 mothers of TLC children with IQ measured, 113 demonstrated mental retardation (IQ <70). Whether maternal IQ was <70 or >or=70, children with IQ >or=85 were rated more favorably on cognitive tests and behavioral questionnaires than children with IQ <85; these measures included Conners' Parent Rating Scale-Revised at age 5, the Developmental Neuropsychological Assessment at ages 5 and 7, and the Behavioral Assessment System for Children at age 7. Among children of mothers with IQ <70, those with IQ >or=85 did not show more severe clinical behavioral problems, nor were they more likely to show multiple behavior problems. Children with higher IQ have fewer behavior problems, irrespective of the mother's IQ. In the special setting of mothers with IQ <70, children with higher IQ are not at greater risk of behavior problems.
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PMID:Maternal IQ, child IQ, behavior, and achievement in urban 5-7 year olds. 1649 92

Elevated levels of lead detected in the blood are associated with harmful effects on children's learning and behavior. The goal of the current Environmental Public Health Tracking Project was to examine the relationship between selected developmental disabilities and childhood blood lead levels in a population-based sample. Using extant datasets from the Florida Department of Health, Childhood Lead Poisoning Prevention Program, and the Florida Department of Education, we were able to isolate a linked dataset of children who were tested for lead poisoning and attended public schools. Special education categories served as a proxy for developmental disabilities; the prevalence of these disabilities in the sample of children with blood lead levels was compared with that in children who attended the same schools but were not tested for lead poisoning. Results indicated that children screened for lead poisoning were more likely to be receiving services for behavior problems, mental retardation, learning disabilities, or a speech-language impairment than other children attending the same schools. Implications for using administrative datasets to examine this relationship are discussed.
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PMID:Tracking childhood exposure to lead and developmental disabilities: examining the relationship in a population-based sample. 1884 78

Appropriate selection and measurement of lead biomarkers of exposure are critically important for health care management purposes, public health decision making, and primary prevention synthesis. Lead is one of the neurotoxicants that seems to be involved in the etiology of psychologies. Biomarkers are generally classified into three groups: biomarkers of exposure, effect, and susceptibility.The main body compartments that store lead are the blood, soft tissues, and bone; the half-life of lead in these tissues is measured in weeks for blood, months for soft tissues, and years for bone. Within the brain, lead-induced damage in the prefrontal cerebral cortex, hippocampus, and cerebellum can lead to a variety of neurological disorders, such as brain damage, mental retardation, behavioral problems, nerve damage, and possibly Alzheimer's disease, Parkinsons disease, and schizophrenia. This paper presents an overview of biomarkers of lead exposure and discusses the neurotoxic effects of lead with regard to children and adults.
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PMID:Neurotoxicity and biomarkers of lead exposure: a review. 2407 21


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