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Biomedical subjects

M Dalton

Publications and source records attributed to M Dalton.

At least 19 recordsLinked to original sources

Effect of protease inhibitor-containing regimens on lymphocyte multidrug resistance transporter expression.

BACKGROUND: Increased expression of multidrug resistance transporters, such as P-glycoprotein (P-gp), has been suggested as a potential mechanism for decreased protease inhibitor (PI) availability at certain intracellular sites and tissue compartments. OBJECTIVES: To investigate the effect of PIs on the surface lymphocyte expression of P-gp in vitro and in vivo. PATIENTS AND METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from healthy subjects (n = 15) and incubated (72 h) with 10 microM of each PI studied (saquinavir, ritonavir, nelfinavir, indinavir, amprenavir and lopinavir), or dimethyl sulphoxide (DMSO) control. PBMCs were also isolated from HIV-infected subjects (n = 50; viral load <50 copies/mL) on a PI- or a non-PI-containing combination antiretroviral regimen. P-gp expression was analysed by flow cytometry. RESULTS: No differences in surface P-gp expression on lymphocytes, CD4+ or CD8+ lymphocyte subsets were observed following incubation with 10 microM saquinavir, ritonavir, indinavir, amprenavir or lopinavir in vitro. Nelfinavir, however, increased P-gp expression. In vivo, no difference in P-gp expression on total lymphocytes was observed between patients receiving a PI-containing regimen [saquinavir n = 9, ritonavir n = 6, nelfinavir n = 7, indinavir n = 7 and lopinavir/ritonavir n = 13, and two nucleoside reverse transcriptase inhibitors (NRTIs)] and patients receiving a control regimen of three NRTIs alone (n = 8). CONCLUSION: This study suggests that, of the PIs, only nelfinavir increases P-gp expression in vitro, and in vivo the PI class of antiretrovirals do not increase P-gp expression on lymphocytes. It is clear that factors other than PI induction are important in the inter-individual variability in the lymphocyte expression of P-gp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Waist circumference, waist-hip ratio and body mass index and their correlation with cardiovascular disease risk factors in Australian adults.

OBJECTIVES: To compare body mass index (BMI), waist circumference and waist-hip ratio (WHR) as indices of obesity and assess the respective associations with type 2 diabetes, hypertension and dyslipidaemia. DESIGN AND SETTING: A national sample of 11 247 Australians aged > or =25 years was examined in 2000 in a cross-sectional survey. MAIN OUTCOME MEASURES: The examination included a fasting blood sample, standard 2-h 75-g oral glucose tolerance test, blood pressure measurements and questionnaires to assess treatment for dyslipidaemia and hypertension. BMI, waist circumference and WHR were measured to assess overweight and obesity. RESULTS: The prevalence of obesity amongst Australian adults defined by BMI, waist circumference and WHR was 20.8, 30.5 and 15.8% respectively. The unadjusted odds ratio for the fourth vs. first quartile of each obesity measurement showed that WHR had the strongest relationship with type 2 diabetes, dyslipidaemia (women only) and hypertension. Following adjustment for age, however, there was little difference between the three measures of obesity, with the possible exceptions of hypertension in women, where BMI had a stronger association, and dyslipidaemia in women and type 2 diabetes in men, where WHR was marginally superior. CONCLUSIONS: Waist circumference, BMI and WHR identified different proportions of the population, as measured by both prevalence of obesity and cardiovascular disease (CVD) risk factors. Whilst WHR had the strongest correlations with CVD risk factors before adjustment for age, the three obesity measures performed similarly after adjustment for age. Given the difficulty of using age-adjusted associations in the clinical setting, these results suggest that given appropriate cut-off points, WHR is the most useful measure of obesity to use to identify individuals with CVD risk factors.

Adult↗

Subject discomfort associated with the histamine challenge in a population study.

BACKGROUND: Many review articles report the safety and lack of serious side-effects associated with the histamine challenge. Even though methacholine and hypertonic saline are more commonly used to measure airway responsiveness, histamine challenges are used in many countries around the world. Levels of subjects discomfort after a challenge have not been quantified. This study quantified the incidence, severity and duration of subject discomfort after histamine challenge. METHODS: Ninety-nine subjects were recruited in an Australian multi-centre population-based study of the genetic epidemiology of asthma. Subjects completed a histamine challenge with final cumulative dose 3.2 micromol. Immediately, and 10 min, after challenge subjects rated their discomfort for cough, headache, throat irritation, hoarse voice and flushed. Research personnel also reported their perception of subjectdiscomfort. RESULTS: Subjects and research personnel reported a small degree of subject discomfort for all symptoms immediately after the histamine challenge. Overall, median symptom scores were less than 1.5 out of 10. Discomfort scores improved 10 min after challenge and cough, throat irritation and flushed improved significantly CONCLUSIONS: This study confirms the tolerability of the histamine challenge.

Adult↗

Disordered eating behaviours in women with Type 2 diabetes mellitus.

The aim of the article is to investigate the relationship between disordered eating, particularly binge eating, and Type 2 diabetes in women. Subjects included 215 women with Type 2 diabetes (mean age: 58.9 years, mean body mass index (BMI)=33.5 kg/m(2)). Measurements included a structured clinical interview for disordered eating (Eating Disorder Examination, EDE), self-report measures of psychological functioning, glycosylated haemoglobin A1c, BMI. A total of 20.9% of women was binge eating regularly. Binge eating was associated with poorer well being, earlier age of diagnosis, poorer self-efficacy for diet and exercise self-management, and higher BMI. Binge eating frequency predicted blood glucose control after controlling for BMI and exercise level. A history of binge eating independently predicted age of diagnosis of diabetes. Binge eating is relatively common in women with Type 2 diabetes. The relationship between binge eating severity and diabetic control is not explained by overweight. Binge eating may be an independent risk factor for Type 2 diabetes.

Journal Article↗

Reasons for non-adherence to antiretroviral therapy: patients' perspectives provide evidence of multiple causes.

The objective of the study was to define common reasons for non-adherence (NA) to highly active antiretroviral therapy (HAART) and the number of reasons reported by non-adherent individuals. A confidential questionnaire was administered to HIV-seropositive patients taking proteinase inhibitor based HAART. Median self-reported adherence was 95% (n = 178, range = 60-100%). The most frequent reasons for at least 'sometimes' missing a dose were eating a meal at the wrong time (38.2%), oversleeping (36.3%), forgetting (35.0%) and being in a social situation (30.5%). The mean number of reasons occurring at least 'sometimes' was 3.2; 20% of patients gave six or more reasons; those reporting the lowest adherence reported a significantly greater numbers of reasons (rho = - 0.59; p < 0.001). Three factors were derived from the data by principal component analysis reflecting 'negative experiences of HAART', 'having a low priority for taking medication' and 'unintentionally missing doses', accounting for 53.8% of the variance. On multivariate analysis only the latter two factors were significantly related to NA (odds ratios 0.845 and 0.849, respectively). There was a wide spectrum of reasons for NA in our population. The number of reasons in an individual increased as adherence became less. A variety of modalities individualized for each patient are required to support patients with the lowest adherence.

Acquired Immunodeficiency Syndrome↗

Does parental disapproval of smoking prevent adolescents from becoming established smokers?

OBJECTIVE: To evaluate the hypothesis that adolescents are less likely to smoke if their parents voice strong disapproval of smoking. DESIGN AND SETTING: Three-wave school-based cohort study of rural Vermont adolescents attending 3 K-12 schools. We evaluate cross-sectional and longitudinal associations between perceived parental disapproval of smoking and the adoption of smoking behavior. OUTCOME MEASURES: Students' perceptions of their parents' reaction to their own smoking was ascertained by asking the following question for mothers and fathers: "How do you think your mother (father) would react if you were smoking cigarettes and she (he) knew about it?" A response of "S/he would tell me to stop and be very upset" was considered to indicate strong parental disapproval. Outcome measures include a 6-level smoking index for cross-sectional analyses and, for a longitudinal analysis of 372 never smokers at baseline, being an established smoker (smoked > or =100 cigarettes lifetime and within the past 30 days) by survey 3. RESULTS: The study samples for the cross-sectional analyses were 662 (baseline), 758 (year 2), and 730 (year 3). Students were equally distributed across grade (4th-11th grades) and gender. At baseline, most (65.9%) adolescents perceived both parents as disapproving of smoking, with 110 (16.6) perceiving 1 parent as disapproving, and 116 (17.5%) perceiving neither parent as disapproving. Perceived disapproval of smoking was inversely associated with adolescent smoking, grade in school, parental and sibling smoking, friend smoking, and ownership of tobacco promotional items. After controlling for confounding influences, adolescents who perceived strong parental disapproval of their smoking were less than half as likely to have higher smoking index levels compared with those who did not perceive strong parental disapproval. In the longitudinal sample of baseline never smokers, those who perceived strong disapproval in both parents at baseline were less than half as likely to become established smokers (adjusted odds ratio 0.4 [0.1, 1.0]). Those who perceived their parents becoming more lenient over time were significantly more likely to progress to established smokers. In all analyses, the effect of parental disapproval of smoking was stronger and more robust than the effect of parent smoking. In addition, the effect of parent disapproval was as strong for parents who smoked as it was for nonsmoking parents. An interaction analysis suggests that the peer smoking effect is attenuated when both parents strongly disapprove of smoking, suggesting that parent disapproval makes adolescents more resistant to the influence of peer smoking. CONCLUSIONS: These findings contrast with the widespread notion that there is little parents can do to prevent their adolescents from becoming smokers. Instead, adolescents who perceive that both parents would respond negatively and be upset by their smoking are less likely to smoke. Interventions that enhance parental self-efficacy in conveying and enforcing no-smoking policies for their children could reduce adolescent smoking.

Adolescent↗

Homocysteine inhibits retinoic acid synthesis: a mechanism for homocysteine-induced congenital defects.

Hyperhomocysteinemia is frequently associated with congenital defects of the heart and neural tube and is a suspected pathogenic factor in atherosclerosis and neoplasia. Results in the present report show homocysteine treatment disrupts normal development of avian embryos; and this effect is prevented by retinoic acid. Based on this, we hypothesize that homocysteine may exert its teratogenic effects by disrupting retinoic acid signaling during development. A reporter cell line transfected with a retinoic acid response element (RARE) linked to a lacZ reporter gene was used to identify the site of retinoid inhibition. Using this reporter cell line, we show that homocysteine inhibits the oxidation of retinal to retinoic acid with concentrations of homocysteine that are in the pathophysiological range (.05 to 0.5 mM). In contrast, homocysteine concentrations as high as 5 mM are unable to inhibit the induction of lacZ by retinoic acid. We show that cellular uptake of homocysteine is sensitive to the specific L-system transport inhibitor, bicycloheptane, and bicycloheptane blocks the inhibition of retinoic acid synthesis by homocysteine, demonstrating that this inhibition occurs intracellularly. These results suggest that homocysteine-induced congenital defects are due to the specific ability of homocysteine to inhibit conversion of retinal to retinoic acid.

Abnormalities, Drug-Induced↗

Effect of cigarette promotions on smoking uptake among adolescents.

BACKGROUND: The purpose of this study was to evaluate the association between receptivity to cigarette promotions and smoking uptake in a cohort of adolescents. METHODS AND MEASURES: This was a prospective cohort study of 480 4th- to 11th-grade students conducted in three rural Vermont K-12 schools. Cigarette use was determined by self-report at baseline, 12 months (survey 2), and 21 months (survey 3). Proportional odds models were used to evaluate smoking uptake as a function of baseline measures of cigarette use, receptivity to cigarette promotions, and confounding factors, including grade, parental education, peer smoking, and family smoking. Adolescents were receptive to cigarette promotions if they owned or were willing to use a personal item bearing a cigarette brand logo [cigarette promotional item (CPI)]. Smoking status was measured using a 6-point ordinal index that combined experience and attitudes: 0 = never smoker/not susceptible to smoking, 1 = never smoker/susceptible to smoking, 2 = puffer (1 cigarette or less in lifetime), 3 = non-current experimenter (2-99 cigarettes in lifetime/none in past 30 days), 4 = current experimenter, and 5 = smoker (> or =100 cigarettes in lifetime). RESULTS: The 480 students were equally distributed across grade at baseline. Environmental exposure to smoking was high, and 30% were receptive to cigarette promotions at baseline. Higher levels on the smoking index at baseline were associated with higher grade in school, peer smoking, and receptivity to cigarette promotions. One hundred eighty-five students (38.5%) had moved to a higher category on the smoking index by survey 3, of whom 30 had become smokers. Receptivity to cigarette promotions at baseline was significantly associated with higher smoking uptake, with 48.7% of receptive students moving up one or more categories on the smoking index [adjusted proportional odds 1.9 (95% CI 1.3, 2.9)]. Acquisition of receptivity to cigarette promotions was also associated with increased smoking uptake, with those becoming receptive in surveys 2 or 3 having significantly higher odds of progression [3.6 (1.8, 7.0) and 2.9 (1.5, 5.5), respectively] compared with those who did not change. Conversely, those who were receptive at one point but became non-receptive in surveys 2 or 3 had lower odds of progression [0.4 (0.2, 0.9) and 0.5 (0.3, 1.1), respectively]. CONCLUSIONS: This study supports a close linkage between tobacco promotional activities and uptake of smoking among adolescents beyond baseline descriptions of receptivity to cigarette promotions. Over time, the likelihood of smoking uptake is increased when an adolescent acquires a CPI or becomes willing to use one and is decreased when an adolescent who owns a CPI loses it or becomes unwilling to use it. This provides strong evidence that elimination of cigarette promotional campaigns could reduce adolescent smoking.

Adolescent↗

Exposure to cigarette promotions and smoking uptake in adolescents: evidence of a dose-response relation.

OBJECTIVE: To assess whether a dose-response relation exists between the number of cigarette promotional items (CPIs) owned by an adolescent, and smoking behaviour. DESIGN AND SETTING: Voluntary, self administered survey of 1265 sixth through to 12th grade students (ages 10-19 years), representing 79-95% of all students attending five rural New Hampshire and Vermont public (state funded) schools in October 1996. The association between the number of CPIs owned by students and smoking behaviour was examined using multivariate regression methods. OUTCOME MEASURES: Adjusted odds of being a smoker (>/= 100 cigarettes lifetime) and, among never and experimental smokers, adjusted cumulative odds of having higher levels on a smoking uptake index given the number of CPIs owned. RESULTS: One third of students owned a CPI (n = 406). Among owners, 211 owned one, 82 owned two, 57 owned three, 24 owned four, 23 owned five, and 7 students owned six CPIs. The number of CPIs owned by students was not associated with grade in school but was significantly higher in males, those with poorer school performance, those who perceived high prevalence of peer smoking, and those with higher exposure to peer and family smoking. The more items a student owned, the greater the chances of being a smoker. For example, smoking prevalence was 11.2% for those not owning a CPI, 41.5% for those owning two, 58.5% for those owning four, and 71.4% for those owning six CPIs. The dose-response relation remained after controlling for confounding; compared with those who did not own a CPI, the likelihood of being a smoker was significantly higher for those who owned one CPI, with an adjusted odds ratio (OR) of 2.7 (95% confidence interval (CI) 1.7 to 4.1); OR was 3.4 (95% CI 1.9 to 5.9) for those owning two CPIs, and 8.4 (95% CI 5.0 to 14.2) for those owning three or more CPIs. After excluding smokers, there was a crude dose-response association between CPI ownership and higher rates of experimentation with cigarettes among sixth to ninth graders (ages 11-15 years) only (n = 543). After controlling for confounding influences, the dose-response relation remained, with the likelihood of being higher on the smoking uptake index rising with the number of CPIs owned: one CPI, adjusted cumulative OR 1.7 (95% CI 1.1 to 2.60); two CPIs, OR 2.5 (95% CI 1.2 to 5.1); and three or more CPIs, OR 4.8 (95% CI 1.9 to 12.2). CONCLUSIONS: This study offers evidence of a dose-response relation between the number of CPIs owned by adolescents and higher likelihood of experimental and established smoking. The dose-response relation persists after controlling for confounding influences. These data provide further support of a causal relation between tobacco promotional campaigns and smoking behaviour among adolescents.

Adolescent↗

Phosphorylation of Tyr319 in ZAP-70 is required for T-cell antigen receptor-dependent phospholipase C-gamma1 and Ras activation.

Accumulating evidence indicates that the interdomain B regions of ZAP-70 and Syk play pivotal roles in the coupling of T-cell antigen receptor (TCR) stimulation to the activation of downstream signaling pathways. The interdomain B region of ZAP-70 contains at least three candidate sites of tyrosine phosphorylation. In this report, we identify Tyr319 as a functionally important phosphorylation site in the ZAP-70 interdomain B region. TCR crosslinkage triggered a rapid increase in the phosphorylation of Tyr319 in Jurkat T cells. Although mutation of Tyr319 to Phe had no effect on the tyrosine kinase activity of ZAP-70, the resulting ZAP(Y319-->F) mutant failed to reconstitute TCR-dependent Ca2+ mobilization, Ras activation, CD69 expression and NFAT-dependent transcription in ZAP-70-deficient Jurkat cells. These defects were correlated with reduced tyrosine phosphorylation of phospholipase C (PLC)-gamma1 and the LAT adapter protein in the ZAP(Y319-->F)-expressing cells. On the other hand, ZAP(Y319-->F)-expressing cells displayed normal increases in SLP-76 phosphorylation and ERK activation during TCR stimulation. Phosphorylation of Tyr319 promoted the association of ZAP-70 with the SH2 domains of two key signaling molecules, Lck and PLC-gamma1. These studies suggest that Tyr319 phosphorylation is required for the assembly of a ZAP-70-containing signaling complex that leads to the activation of the PLC-gamma1- and Ras-dependent signaling cascades in antigen-stimulated T cells.

Adaptor Proteins, Signal Transducing↗

Early use of inhaled nedocromil sodium in children following an acute episode of asthma.

BACKGROUND: Current guidelines on the treatment of childhood asthma recommend the introduction of an anti-inflammatory drug in children who have persistent symptoms and require regular treatment with a bronchodilator. The efficacy and safety of inhaled nedocromil sodium (Tilade Mint aerosol) administered using a Fisonair spacer at a dose of 4 mg three times daily was compared with placebo in the treatment of asthmatic children aged 6-12 years who are symptomatic and recovering from an acute exacerbation of asthma. METHODS: A group comparative, double blind, placebo controlled trial was performed in children who were recovering from an acute episode of asthma following treatment in the emergency department of the hospital or in children referred from their general practitioner following a wheezing episode and documented evidence of at least two previous episodes of wheezing. A two week baseline period on existing bronchodilator treatment was followed by a 12 week treatment period on either nedocromil sodium (2 mg/puff) or placebo. Both treatments were administered using a Fisonair spacer at a dose of two puffs three times daily. Changes from baseline values in daytime asthma and night time asthma symptom scores, usage of rescue bronchodilators, mean peak expiratory flow (PEF) recorded twice daily on diary cards, patients' opinion of treatment, and withdrawals due to treatment failure were measured during the primary treatment period (last six weeks of treatment). RESULTS: One hundred and forty two children aged 6-12 years entered the baseline period. Sixty three were withdrawn due to failure to meet the entry criteria (18) or the criteria for asthma symptom severity (15) or reversibility (9), because they developed uncontrolled asthma (2), because they took disallowed treatment (2), or for other non-trial related reasons (17). Seventy nine patients (46 boys) of mean age 8. 8 years entered the treatment period. There were significant differences in the changes from baseline values during the last six weeks of treatment in favour of nedocromil sodium compared with placebo in the primary variables of daytime asthma and night time asthma, morning and evening PEF, and the usage of rescue inhaled bronchodilators; 53% of patients reported nedocromil sodium to be very or moderately effective compared with 44% placebo. Improvement in asthma symptoms, PEF, and reduction in use of rescue bronchodilators did not reach statistical significance until after six weeks of treatment. Twenty two patients were withdrawn or dropped out during the treatment phase, 12 due to uncontrolled asthma or persistence of asthma symptoms, four due to suspected adverse drug reactions (nedocromil sodium 3 (headaches 2, angio-oedema/urticaria 1), placebo 1(persistent cough)), and six due to non-treatment related reasons. Seventy one adverse events were reported by 27 patients in the nedocromil group and 75 by 30 patients in the placebo group. CONCLUSIONS: Asthma symptoms, use of bronchodilators, and lung function can be improved significantly in children recovering from an acute exacerbation of asthma or wheeze and currently receiving treatment with bronchodilators alone by the addition of inhaled nedocromil sodium at a dose of 4 mg three times daily administered using a Fisonair holding chamber.

Acute Disease↗

High concentrations of heavy metals in neighborhoods near ore smelters in northern Mexico.

In developing countries, rapid industrialization without environmental controls has resulted in heavy metal contamination of communities. We hypothesized that residential neighborhoods located near ore industries in three northern Mexican cities would be heavily polluted with multiple contaminants (arsenic, cadmium, and lead) and that these sites would be point sources for the heavy metals. To evaluate these hypotheses, we obtained samples of roadside surface dust from residential neighborhoods within 2 m of metal smelters [Torreón (n = 19)] and Chihuahua (n = 19)] and a metal refinery [Monterrey (n = 23)]. Heavy metal concentrations in dust were mapped with respect to distance from the industrial sites. Correlation between dust metal concentration and distance was estimated with least-squares regression using log-transformed data. Median dust arsenic, cadmium, and lead concentrations were 32, 10, and 277 microg/g, respectively, in Chihuahua; 42, 2, and 467 microg/g, respectively, in Monterrey, and 113, 112, and 2,448 microg/g, respectively, in Torreón. Dust concentrations of all heavy metals were significantly higher around the active smelter in Torreón, where more than 90% of samples exceeded Superfund cleanup goals. At all sites, dust concentrations were inversely related to distance from the industrial source, implicating these industries as the likely source of the contamination. We concluded that residential neighborhoods around metal smelting and refining sites in these three cities are contaminated by heavy metals at concentrations likely to pose a health threat to people living nearby. Evaluations of human exposure near these sites should be conducted. Because multiple heavy metal pollutants may exist near smelter sites, researchers should avoid attributing toxicity to one heavy metal unless others have been measured and shown not to coexist.

Arsenic↗

Diagnostic testing unwarranted for children with blood lead 10 to 14 microg/dL.

BACKGROUND: Recent statements from the American Academy of Pediatrics and Centers for Disease Control and Prevention recommend diagnostic venous blood lead testing within 90 days of a marginally elevated screening test (10-14 microg/dL). OBJECTIVE: To evaluate the ability of a marginally elevated capillary (CScr) or venous (VScr) blood lead screening test to predict venous diagnostic (VPb) blood lead (taken within 90 days of the screening test) that would prompt environmental evaluation (>/=20 microg/dL). DESIGN: Population-based follow-up study comparing CScr and VScr with VPb drawn within 90 days of the screening sample. This study population was drawn from all children aged 0 to 4 years who were screened in Worcester County, Massachusetts, and Providence County, Rhode Island, with CScr and VScr during calendar year 1994. OUTCOME MEASURES: To evaluate predictive validity, CScr and VScr were correlated with VPb. CScr, VScr, and VPb results were then separated into the following categories: <10, 10 to 14, 15 to 19, and >/=20 microg/dL. CScr and VScr categories were cross-tabulated against VPb categories, and logistic regression analysis was used to evaluate categorical elevations of CScr and VScr as predictors of VPb >/=20 microg/dL. RESULTS: Of 31 904 children screened with CScr, 5450 (17.1%) were elevated and 1278 were followed up with VPb within 90 days. Of 14 623 children screened with VScr, 2979 (20.4%) were elevated and 614 were followed up with VPb within 90 days. CScr was only weakly correlated with VPb (r = 0.39), whereas VScr was more strongly correlated with VPb (r = 0.73). Compared with CScr <10 microg/dL, CScr in the 10 to 14 microg/dL range did not identify a higher percentage of children with VPb elevation in any category, and falsely misclassified as lead poisoned some 77% of children. Compared with VScr <10 microg/dL, VScr in the 10 to 14 microg/dL range identified higher percentages of children with VPb in the 10 to 19 microg/dL range but not with VPb >/=20 microg/dL, and falsely misclassified as lead poisoned 42% of children. Compared with screening tests <10 microg/dL, the odds of identifying a child with VPb >/=20 were no different from 1 for CScr of 10 to 14 microg/dL (adjusted odds ratio 1.4 [95% confidence interval 0.3, 6.6]), CScr of 15 to 19 microg/dL (3.2 [0.7, 15.7]), or VScr of 10 to 14 microg/dL (0.9 [0.3, 3.0]). CScr and VScr in the 15 to 19 microg/dL range were associated with significantly higher odds of having VPb >/=20 microg/dL when compared with screening tests <10 microg/dL. CONCLUSIONS: These data indicate that special diagnostic testing within 90 days for children with CScr and VScr in the 10 to 14 microg/dL range does not result in greater identification of VPb >/=20. Raising the set point for diagnostic testing to 15 microg/dL in this sample would eliminate the unnecessary follow-up of 5162 children, of whom 3360 were falsely misclassified as having undue lead exposure.

Child, Preschool↗

The association between state housing policy and lead poisoning in children.

OBJECTIVES: This study examined the effect of an active program of household lead paint hazard abatement, applied over 22 years, on childhood lead poisoning in Massachusetts. METHODS: A small areas analysis was used to compare screening blood lead levels of children in Worcester County, Mass (n = 27,590), with those in Providence County, RI (n = 19,071). Data were collapsed according to census tract. RESULTS: The percentage of children with lead poisoning (blood lead level > or = 20 micrograms/dL [Pe20]) was, on average, 3 times higher in Providence County census tracts (3.2% vs 0.9% in Worcester County census tracts, P < .0001), despite similar percentages of pre-1950s housing in both counties. The ratio of Pe20 in Providence vs Worcester County census tracts was 2.2 (95% confidence interval = 1.8, 2.7), after adjustment for differences in housing, sociodemographic, and screening characteristics. This estimate was robust to alternative regression methods and sensitivity analyses. CONCLUSIONS: Massachusetts policy, which requires lead paint abatement of children's homes and places liability for lead paint poisoning on property owners, may have substantially reduced childhood lead poisoning in that state.

Child↗