1: J Dev Behav Pediatr 2002 Feb;23(1 Suppl):S13-22
In harm's way: toxic threats to child development.
Stein J, Schettler T, Wallinga D, Valenti M.
Developmental disabilities result from complex interactions of genetic, toxicologic (chemical), and social factors. Among these various causes, toxicologic exposures deserve special scrutiny because they are readily preventable. This article provides an introduction to some of the literature addressing the effects of these toxicologic exposures on the developing brain. This body of research demonstrates cause for serious concern that commonly encountered household and environmental chemicals contribute to developmental disabilities. The developing brain is uniquely susceptible to permanent impairment by exposure to environmental substances during time windows of vulnerability. Lead, mercury, and polychlorinated biphenyls (PCBs) have been extensively studied and found to impair development at levels of exposure currently experienced by significant portions of the general population. High-dose exposures to each of these chemicals cause catastrophic developmental effects. More recent research has revealed toxicity at progressively lower exposures, illustrating a "declining threshold of harm" commonly observed with improved understanding of developmental toxicants. For lead, mercury, and PCBs, recent studies reveal that background-population exposures contribute to a wide variety of problems, including impairments in attention, memory, learning, social behavior, and IQ. Unfortunately, for most chemicals there is little data with which to evaluate potential risks to neurodevelopment. Among the 3000 chemicals produced in highest volume (over 1 million lbs/yr), only 12 have been adequately tested for their effects on the developing brain. This is a matter of concern because the fetus and child are exposed to untold numbers, quantities, and combinations of substances whose safety has not been established. Child development can be better protected by more precautionary regulation of household and environmental chemicals. Meanwhile, health care providers and parents can play an important role in reducing exposures to a wide variety of known and suspected neurodevelopmental toxicants that are widely present in consumer products, food, the home, and wider community.
Publication Types: Review Review, Tutorial
PMID: 11875286 [PubMed - indexed for MEDLINE]
1: Altern Med Rev 2000 Oct;5(5):402-28
Comment in: Altern Med Rev. 2000 Oct;5(5):401.
Attention deficit/hyperactivity disorder (ADHD) in children: rationale for its integrative management.
Attention Deficit/Hyperactivity Disorder (ADHD) is the most common behavioral disorder in children. ADHD is characterized by attention deficit, impulsivity, and sometimes overactivity ("hyperactivity"). The diagnosis is empirical, with no objective confirmation available to date from laboratory measures. ADHD begins in childhood and often persists into adulthood. The exact etiology is unknown; genetics plays a role, but major etiologic contributors also include adverse responses to food additives, intolerances to foods, sensitivities to environmental chemicals, molds, and fungi, and exposures to neurodevelopmental toxins such as heavy metals and organohalide pollutants. Thyroid hypofunction may be a common denominator linking toxic insults with ADHD symptomatologies. Abnormalities in the frontostriatal brain circuitry and possible hypofunctioning of dopaminergic pathways are apparent in ADHD, and are consistent with the benefits obtained in some instances by the use of methylphenidate (Ritalin) and other potent psychostimulants. Mounting controversy over the widespread use of methylphenidate and possible life-threatening effects from its long-term use make it imperative that alternative modalities be implemented for ADHD management. Nutrient deficiencies are common in ADHD; supplementation with minerals, the B vitamins (added in singly), omega-3 and omega-6 essential fatty acids, flavonoids, and the essential phospholipid phosphatidylserine (PS) can ameliorate ADHD symptoms. When individually managed with supplementation, dietary modification, detoxification, correction of intestinal dysbiosis, and other features of a wholistic/integrative program of management, the ADHD subject can lead a normal and productive life.
Publication Types: Review Review, Tutorial
PMID: 11056411 [PubMed - indexed for MEDLINE]
1: Am J Clin Nutr 2000 Jan;71(1 Suppl):327S-30S
Long-chain polyunsaturated fatty acids in children with attention-deficit hyperactivity disorder.
Burgess JR, Stevens L, Zhang W, Peck L.
Attention-deficit hyperactivity disorder (ADHD) is the diagnosis used to describe children who are inattentive, impulsive, and hyperactive. ADHD is a widespread condition that is of public health concern. In most children with ADHD the cause is unknown, but is thought to be biological and multifactorial. Several previous studies indicated that some physical symptoms reported in ADHD are similar to symptoms observed in essential fatty acid (EFA) deficiency in animals and humans deprived of EFAs. We reported previously that a subgroup of ADHD subjects reporting many symptoms indicative of EFA deficiency (L-ADHD) had significantly lower proportions of plasma arachidonic acid and docosahexaenoic acid than did ADHD subjects with few such symptoms or control subjects. In another study using contrast analysis of the plasma polar lipid data, subjects with lower compositions of total n-3 fatty acids had significantly more behavioral problems, temper tantrums, and learning, health, and sleep problems than did those with high proportions of n-3 fatty acids. The reasons for the lower proportions of long-chain polyunsaturated fatty acids (LCPUFAs) in these children are not clear; however, factors involving fatty acid intake, conversion of EFAs to LCPUFA products, and enhanced metabolism are discussed. The relation between LCPUFA status and the behavior problems that the children exhibited is also unclear. We are currently testing this relation in a double-blind, placebo-controlled intervention in a population of children with clinically diagnosed ADHD who exhibit symptoms of EFA deficiency.
Publication Types: Review Review, Tutorial
PMID: 10617991 [PubMed - indexed for MEDLINE]
1: US News World Rep 1999 Dec 20;127(24):54-6
In the air that they breathe. Lead poisoning remains a major health hazard for America's children.
Spake A, Couzin J.
PMID: 10724814 [PubMed - indexed for MEDLINE]
1: Mo Med 1997 Jun;94(6):295-7
Results of blood lead screening in children referred for behavioral disorders.
Eppright TD, Vogel SJ, Horwitz E, Tevendale HD.
University of Missouri-Columbia, Department of Psychiatry/Neurology, USA.
This study reviews findings from blood lead level screening in children referred to an Attention Deficit Hyperactivity Disorder clinic. Results obtained from 102 children revealed a sample mean blood lead level of 2.29 micrograms/dL and one patient with a mildly elevated blood lead level. Comparing these findings to results of national studies suggests that these children are not at higher risk for elevated lead levels than is the average child living in a similar setting.
PMID: 9193134 [PubMed - indexed for MEDLINE]
1: Arch Environ Health 1996 May-Jun;51(3):214-20
Hair lead levels related to children's classroom attention-deficit behavior.
School of Public Health, University of Massachusetts, Amherst, USA.
The goal of this study was to evaluate the relationship between hair lead levels of children and their attention-deficit behaviors in the classroom. Scalp hair specimens were obtained from 277 first-grade pupils, teachers completed the abbreviated Boston Teacher's Rating Scale for rating classroom attention-deficit behavior, and parents completed a short questionnaire. The children's hair lead concentrations ranged from less than 1 to 11.3 ppm (microg/g). The striking dose-response relationship between levels of lead and negative teacher ratings remained significant after controlling for age, ethnicity, gender, and socioeconomic status. An even stronger relationship existed between physician-diagnosed attention-deficit hyperactivity disorder and hair lead in the same children. There was no apparent 'safe' threshold for lead. Scalp hair should be considered a useful clinical and epidemiologic approach for the measurement of chronic low-level lead exposure in children.
PMID: 8687242 [PubMed - indexed for MEDLINE]
1: Mo Med 1996 Mar;93(3):136-8
Attention deficit hyperactivity disorder, infantile autism, and elevated blood-lead: a possible relationship.
Eppright TD, Sanfacon JA, Horwitz EA.
Deparment of Psychiatry and Neurology, University of Missouri-Columbia, 65212
This case involves a 4 1/2-year-old boy diagnosed with autism, attention deficit hyperactivity disorder (ADHD), and an elevated blood-lead level of 42 mcg/dl. The child was treated for the elevated blood-lead with the chelating agent succimer. The parents reported a decrease in repetitive behaviors while on succimer with a regression to previous symptoms when medication was discontinued. Also seen was a decrease of hyperactive behavior while being treated with succimer. This article explores the interaction and possible casual relationship of an elevated blood-lead, autism, and ADHD as well as treatment of the behavioral symptoms.
PMID: 8867271 [PubMed - indexed for MEDLINE]
1: J Learn Disabil 1994 Jun-Jul;27(6):393-9
Exposure to lead and specific attentional problems in schoolchildren.
Minder B, Das-Smaal EA, Brand EF, Orlebeke JF.
Department of Physiological Psychology, Vrije Universiteit of Amsterdam, The Netherlands.
A pilot study was carried out to investigate the relationship between exposure to lead and attention in children. The participants were 43 boys, 8 to 12 years of age, attending special schools for children with educational and/or learning problems (so called LOM schools). Children with probable causes of attentional or memory problems other than lead contamination were excluded from the study. Various aspects of attention were measured using neuropsychological tests. As an assessment of body lead burden, lead concentration in the boys' hair was measured by means of the Synchrotron Radiation-Induced X-ray Fluorescence technique (SXRF). Information was collected about variables that possibly could influence attention and/or body lead burden (confounding factors). A multiple regression analysis was used to determine the contribution of lead to variance in performance, after correction for confounding factors. The results showed that children with relatively high concentrations of lead in their hair reacted significantly slower in a simple reaction-time task than did children with relatively low concentrations of lead in their hair. In addition, the former were significantly less flexible in changing their focus of attention, even after correction for the influence of their delayed reaction time.
PMID: 7519655 [PubMed - indexed for MEDLINE]
1: J Child Psychol Psychiatry 1989 Jul;30(4):515-28
Blood-lead levels and children's behaviour--results from the Edinburgh Lead Study.
Thomson GO, Raab GM, Hepburn WS, Hunter R, Fulton M, Laxen DP.
Department of Education, University of Edinburgh, U.K.
The effect of blood-lead on children's behaviour was investigated in a sub-sample of 501 boys and girls aged 6-9 years from 18 primary schools within a defined area of central Edinburgh. Behaviour ratings of the children were made by teachers and parents using the Rutter behaviour scales. An extensive home interview with a parent was also carried out. Multiple regression analyses showed a significant relationship between log blood-lead and teachers' ratings on the total Rutter score and the aggressive/anti-social and hyperactive sub-scores, but not the neurotic sub-score when 30 possible confounding variables were taken into account. There was a dose-response relationship between blood-lead and behaviour ratings, with no evidence of a threshold.
PMID: 2768355 [PubMed - indexed for MEDLINE]
1: Aust Paediatr J 1988 Apr;24(2):143-7
Synthetic food colourings and 'hyperactivity': a double-blind crossover study.
Department of Paediatrics, Royal Children's Hospital, Parkville, Victoria, Australia.
Of 220 children referred for suspected 'hyperactivity', 55 were subjected to a 6 week trial of the Feingold diet. Forty (72.7%) demonstrated improved behaviour and 26 (47.3%) remained improved following liberalization of the diet over a period of 3-6 months. The parents of 14 children claimed that a particular cluster of behaviours was associated with the ingestion of foods containing synthetic colourings. A double-blind crossover study, employing a single-subject repeated measures design was conducted, using eight of these children. Subjects were maintained on a diet free from synthetic additives and were challenged daily for 18 weeks with either placebo (during lead-in and washout periods) or 50 mg of either tartrazine or carmoisine, each for 2 separate weeks. Two significant reactors were identified whose behavioural pattern featured extreme irritability, restlessness and sleep disturbance. One of the reactors did not have inattention as a feature. The findings raise the issue of whether the strict criteria for inclusion in studies concerned with 'hyperactivity' based on 'attention deficit disorder' may miss children who indicate behavioural changes associated with the ingestion of food colourings. Moreover, for further studies, the need to construct a behavioural rating instrument specifically validated for dye challenge is suggested.
Publication Types: Clinical Trial Controlled Clinical Trial
PMID: 3395307 [PubMed - indexed for MEDLINE]
1: Dan Med Bull 1980 Dec 6;27(6):259-62
Hair lead concentration in children with minimal cerebral dysfunction.
Hansen JC, Christensen LB, Tarp U.
PMID: 7460632 [PubMed - indexed for MEDLINE]
1: Pediatrics 1984 Jul;74(1):103-11
Effects of megavitamin therapy on children with attention deficit disorders.
Haslam RH, Dalby JT, Rademaker AW.
The effectiveness of a megavitamin regimen utilizing a two-stage trial in 41 subjects with attention deficit disorders was studied. Stage 1 was a 3-month clinical trial of vitamins (daily maximum: 3 g of niacinamide and ascorbic acid, 1.2 g of calcium pantothenate, and 0.6 g of pyridoxine). State 2 consisted of four, 6-week, double-blind repeated crossover periods. Twenty-nine per cent of the subjects showed significant behavior improvement during stage 1, and these subjects were used in the double-blind crossover phase of the study to evaluate megavitamin therapy. Using analysis of variance methods for crossover studies, there was no significant difference (P greater than .05) in most behavior scores between children receiving vitamin and those receiving placebo during stage 2. Children exhibited 25% more disruptive classroom behavior when treated with vitamins v placebo (P less than .01). There was no significant difference in serum pyridoxine and ascorbic acid levels between subjects and control subjects. Forty-two per cent of subjects exceeded the upper limits of serum transaminase levels while receiving vitamins. It is concluded that megavitamins are ineffective in the management of attention deficit disorders and should not be utilized because of their potential hepatotoxicity.
Publication Types: Clinical Trial Randomized Controlled Trial
PMID: 6234505 [PubMed - indexed for MEDLINE]
1: JAMA 1978 Dec 8;240(24):2642-3
Megavitamins for minimal brain dysfunction. A placebo-controlled study.
Arnold LE, Christopher J, Huestis RD, Smeltzer DJ.
Preliminary to a stimulant comparison study, 31 children with minimal brain dysfunction randomly received either placebo or a megavitamin combination. During a two-week trial, only two children responded so well that stiumlants were not considered necessary; both were in the placebo group. Change scores from pretest to posttest on four blind ratings by teachers and parents did not show a significant difference between the placebo and vitamin groups.
Publication Types: Clinical Trial Randomized Controlled Trial
PMID: 712981 [PubMed - indexed for MEDLINE]
1: Pediatrics 1974 May;53(5):851-9
The susceptibility of the fetus and child to chemical pollutants. Behavioral implications of prenatal and early postnatal exposure to chemical pollutants.
Weiss B, Spyker JM.
PMID: 4416519 [PubMed - indexed for MEDLINE]
1: N Engl J Med 1972 Mar 30;286(13):702-10
Undue absorption of lead among children--a new look at an old problem.
Publication Types: Review
PMID: 4551386 [PubMed - indexed for MEDLINE]