Mental retardation in ten-year-old children in relation to their mothers' employment during pregnancy

We conducted a case-control study to examine relationships between potential risk factors in women's prenatal occupational histories and subsequent mental retardation in their 10-year-old children. Children with mental retardation (intelligence quotient less than 71) were identified from special education records maintained by the public school systems in the metropolitan Atlanta area and from records of various medical and social service agencies serving children with special needs. Control children were chosen from the rosters of 10-year-olds who were enrolled in regular education classes in the local public school systems. To obtain occupational histories, sociodemographic data, and other information, we interviewed 352 natural mothers (67%) of 525 case children and 408 natural mothers (64%) of 636 control children. We computed odds ratios for each of 25 selected occupation, industry, and agent categories controlling for maternal education, birth order, and race. Most comparisons yielded odds ratios that were not indicative of unusual risks, but we did find lower than expected risks among children of teachers and health-care professionals. We also found a strong, positive association between mental retardation and maternal employment in the textile and apparel industries. The findings are useful for planning the direction of future studies of childhood cognitive ability to focus on specific parental occupations or industries. © 1993 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Evaluation of a Records-Review Surveillance System Used to Determine the Prevalence of Autism Spectrum Disorders

We conducted the first study that estimates the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a population-based autism spectrum disorders (ASD) surveillance system developed at the Centers for Disease Control and Prevention. The system employs a records-review methodology that yields ASD classification (case versus non-ASD case) and was compared with classification based on clinical examination. The study enrolled 177 children. Estimated specificity (0.96, [CI_.95 = 0.94, 0.99]), PPV (0.79 [CI_.95 = 0.66, 0.93]), and NPV (0.91 [CI_.95 = 0.87, 0.96]) were high. Sensitivity was lower (0.60 [CI_.95 = 0.45, 0.75]). Given diagnostic heterogeneity, and the broad array of ASD in the population, identifying children with ASD is challenging. Records-based surveillance yields a population-based estimate of ASD that is likely conservative.     

Mild mental retardation in black and white children in metropolitan Atlanta: a case-control study.

OBJECTIVES. This study assessed differences in the prevalence of mild mental retardation, defined as an intelligence quotient (IQ) from 50 to 70, between Black and White children. METHODS. A case-control study design was used. Ten-year-old children with mental retardation were identified from multiple sources. Information on race, sex, maternal age, birth order, economic status, and maternal education was abstracted from birth certificates of 330 case children and 563 control children (public school students). RESULTS. The crude Black-White odds ratio (OR) was 2.6, but it was reduced to 1.8 after the other five covariates were controlled. The disparity was largest among children whose mental retardation was first diagnosed when they were 8 to 10 years old (adjusted OR = 2.5). We found no significant difference in the occurrence of mild mental retardation between Black and White children diagnosed before the age of 6 years (adjusted OR = 1.2). Black children had a higher prevalence of mild mental retardation within all strata of the other five covariates. CONCLUSIONS. Five sociodemographic factors accounted for approximately half of the excess prevalence of mild mental retardation among Black children. Possible reasons for the residual difference are discussed.     

Inhibitory action of hydrogen sulfide on muscarinic receptor-induced contraction of isolated porcine irides

We investigated the pharmacological actions of hydrogen sulfide (H₂S) using sodium hydrosulfide (NaHS) and sodium sulfide (Na₂S) as donors on isolated porcine irides in the presence of tone induced by muscarinic receptor stimulation. Furthermore, we also investigated the mechanism of action of H₂S in this smooth muscle. Isolated porcine iris muscle strips were set up in organ baths and prepared for measurement of longitudinal isometric tension. The relaxant action of NaHS or Na₂S on carbachol-induced tone was studied in the absence and presence of a K⁺-channel inhibitor and inhibitors/activators of enzymes of the biosynthetic pathways for H₂S, prostanoid and nitric oxide production. In the concentration range, 10 nM to 100 μM, NaHS produced a concentration-dependent relaxation of carbachol-induced tone reaching a maximum of inhibition of 28% at 30 μM. The cyclooxygenase inhibitor, flurbiprofen (1 μM), enhanced relaxations induced by both NaHS and Na₂S yielding IC₅₀ values of 7 μM and 70 μM, respectively. With exception of l-NAME (300 μM) inhibitors of cystathionine γ-lyase, propargylglycine, (PAG) (1 mM) and β-cyanoalanine, (BCA) (1 mM) and inhibitors of cystathionine β-synthase, aminooxyacetic acid (AOA) (30 μM) and hydroxylamine (HOA) (30 μM) caused significant (P < 0.001) rightward shifts in the concentration-response curves to NaHS. An activator of cystathionine β-synthase, SAM (100 μM), enhanced relaxations elicited by low concentrations of NaHS but attenuated responses caused by the higher concentrations of this H₂S donor. The inhibitor of K_ATP channel, glibenclamide (100 and 300 μM), blocked relaxations induced by NaHS. We conclude that the observed inhibitory action of NaHS and Na₂S in isolated porcine irides is dependent on endogenous production of prostanoids and the biosynthesis of H₂S by cystathionine γ-lyase and cystathionine β-synthase. Furthermore, relaxation induced by H₂S is mediated, at least in part, by K_ATP channels. Nitric oxide is not involved in the relaxation induced by this gas in the isolated porcine irides.     

Prevalence of intellectual disability among eight-year-old children from selected communities in the United States, 2014

BackgroundChildren with intellectual disability (ID), characterized by impairments in intellectual functioning and adaptive behavior, benefit from early identification and access to services. Previous U.S. estimates used administrative data or parent report with limited information for demographic subgroups.ObjectiveUsing empiric measures we examined ID characteristics among 8-year-old children and estimated prevalence by sex, race/ethnicity, geographic area and socioeconomic status (SES) area indicators.MethodsWe analyzed data for 8-year-old children in 9 geographic areas participating in the 2014 Autism and Developmental Disabilities Monitoring Network. Children with ID were identified through record review of IQ test data. Census and American Community Survey data were used to estimate the denominator.ResultsOverall, 11.8 per 1,000 (1.2%) had ID (IQ ≤ 70), of whom 39% (n = 998) also had autism spectrum disorder. Among children with ID, 1,823 had adaptive behavior test scores for which 64% were characterized as impaired. ID prevalence per 1,000 was 15.8 (95% confidence interval [95% CI], 15.0–16.5) among males and 7.7 (95% CI, 7.2–8.2) among females. ID prevalence was 17.7 (95% CI, 16.6–18.9) among children who were non-Hispanic black; 12.0 (95% CI, 11.1–13.0), among Hispanic; 8.6 (95% CI, 7.1–10.4), among non-Hispanic Asian; and 8.0 (95% CI, 7.5–8.6), among non-Hispanic white. Prevalence varied across geographic areas and was inversely associated with SES.ConclusionsID prevalence varied substantively among racial, ethnic, geographic, and SES groups. Results can inform strategies to enhance identification and improve access to services particularly for children who are minorities or living in areas with lower SES.