Prenatal exposure to legacy contaminants and visual acuity in Canadian infants: a maternal-infant research on environmental chemicals study (MIREC-ID).

BACKGROUND: Prenatal exposure to environmental contaminants can have deleterious effects on child development. While psychomotor, cognitive and behavioural outcomes have been investigated in relation to chronic exposure, the associations with visual functions remains unclear. The present study's aim was to assess the associations of prenatal exposure to legacy persistent organic pollutants and heavy metals with visual acuity in Canadian infants. The potential protective effects of selenium against mercury toxicity were also examined. METHODS: Participants (mean corrected age = 6.6 months) were part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), lead and mercury were measured in maternal blood during pregnancy, as well as in the cord blood. The Teller acuity card test (TAC) (n = 429) and the visual evoked potentials in a sub-group (n = 63) were used to estimate behavioural and electrophysiological visual acuity, respectively. Multivariable linear regression models were used to investigate the relationship between exposure to each contaminant and visual acuity measures, while controlling for potential confounders. Breastmilk selenium, which was available for about half of the TAC and VEP samples, was also taken into account in the mercury models as exploratory analyses. RESULTS: We observed no significant associations between exposure to any contaminants and TAC. Analyses revealed a negative trend (p values < 0.1) between cord blood lead and mercury and electrophysiological visual acuity, whereas PCB and PBDE showed no association. When adding breastmilk selenium concentration to the mercury models, this association became statistically significant for cord concentrations (ß = - 3.41, 95% CI = - 5.96,-0.86), but also for blood levels at 1st and 3rd trimesters of pregnancy (ß = - 3.29, 95% CI = - 5.69,-0.88). However, further regression models suggested that this change in estimates might not be due to adjustment for selenium, but instead to a change in the study sample. CONCLUSIONS: Our results suggest that subtle, but detectable alterations of infant electrophysiological visual acuity can be identified in a population prenatally exposed to low mercury concentrations. Compared to behavioural visual acuity testing, electrophysiological assessment may more sensitive in detecting visual neurotoxicity in relation with prenatal exposure to mercury.

Validation of a HOME Injury Survey.

BACKGROUND: There are no validated observational surveys to assess injury hazards in the home environment. OBJECTIVE: To evaluate the reproducibility and reliability of a survey quantifying home injury hazards for children. METHODS: A nested cohort of children in the intervention arm of the Home Observations and Measures of the Environment (HOME) Study trial were analysed. The number and density of hazards were quantified by research assistants in the homes of participants at a baseline visit (BHV) for four high-risk rooms (kitchen, main activity room, child's bathroom and child's bedroom) and stairways and later at an intervention planning visit (IPV) for the four high-risk rooms and entire household. Statistical analysis included Pearson correlation, Bland-Altman analysis of agreement, analysis of variance and kappa statistics. RESULTS: There were 163 households with measurements at BHV and IPV. The number and density of hazards for the four high-risk rooms correlated significantly between BHV and IPV (r = 0.50 and 0.75, respectively). The number and density of hazards for the four high-risk rooms correlated significantly with that for the whole household at the IPV (r = 0.17 and 0.52, respectively). The number of injury hazards was significantly higher in the kitchen than in the other high-risk rooms, whereas density was highest in the child's bathroom. Inter-rater reliability between research assistants, as measured by the kappa statistic, was excellent with a mean of 0.81. CONCLUSIONS: The HOME Injury Survey was a reliable and replicable tool for quantifying residential injury hazards. The density of injury hazards was a more stable and valid measure than the number of injury hazards.

Household interventions for prevention of domestic lead exposure in children.

BACKGROUND: Lead poisoning is associated with physical, cognitive and neurobehavioral impairment in children and many household interventions to prevent lead exposure have been trialled. OBJECTIVES: To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development. SEARCH STRATEGY: Trials were identified through electronic searches of CENTRAL 2006 (Issue 1), MEDLINE 1966 to March 2006, and thirteen other electronic databases and contacting experts to find unpublished studies. SELECTION CRITERIA: Randomised and quasi randomised trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported. DATA COLLECTION AND ANALYSIS: Two reviewers independently reviewed all eligible studies for inclusion, assessed study quality and extracted data. Triallists were contacted to obtain missing information. MAIN RESULTS: Twelve studies (2239 children) were included. All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. Studies were subgrouped according to their intervention type. Meta-analysis of both continuous and dichotomous data was performed for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: WMD 0.13, 95% CI -0.30, 0.56, I2 = 41.6; dichotomous >/= 10 microg/dL (>/= 0.48 micromol/l): RR 1.02 (95% CI 0.79, 1.30, I2 = 0); dichotomous >/= 15 microg/dL (>/=0.72 micromol/l): RR 0.60, 95% CI 0.33, 1.09, I2 = 0). Meta-analysis of the dichotomous data for the dust control subgroup found no evidence of effectiveness. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies. AUTHORS' CONCLUSIONS: Currently there is no evidence of effectiveness for household interventions for education or dust control measures in reducing blood lead levels in children as a population health measure. There is insufficient evidence for soil abatement or combination interventions. Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements should include longer term follow up and measures of compliance as well as performing trials in developing countries and differing socio-economic groups in developed countries.

A pilot study to investigate the effects of combined dehumidification and HEPA filtration on dew point and airborne mold spore counts in day care centers.

UNLABELLED: Meteorological factors such as relative humidity directly correlate with airborne fungal levels outdoors and indoors. While dehumidification alone is effective at reducing moisture necessary for mold growth, it is inadequate as a single intervention as it does not remove viable and non-viable fungal spores that are potentially allergenic. The purpose of this pilot study was to investigate whether dehumidification in combination with high-efficiency particulate arrestance (HEPA) filtration is effective at reducing airborne mold spore levels in day care centers. Two day care centers within a 2-mile radius of each other were selected. Day care center A was 2 years old with eight rooms while day care center B was 15 years old with six rooms. A high efficiency Santa Fe dehumidification unit equipped with a HEPA filter was installed in half the rooms (intervention) of each day care facility. Electronic HOBO data loggers continuously measured outdoor and indoor room dew point and temperature every 2 h throughout the study. Dew point and airborne fungal spore measurements from selected rooms with controlled air conditions were analyzed by comparing baseline measurements to those obtained at subsequent time periods over 1 year. Regression models accounted for correlations between measurements in the same room over time. Intervention resulted in a lowered average dew point from baseline by 8.8 degrees C compared with a decrease of 7.1 degrees C in non-intervention rooms across all time periods in both facilities (P<0.001). Fungal analyses demonstrated lower baseline (P=0.06) and follow-up means in intervention rooms (P<0.05), however the change from baseline to end of follow-up differed between intervention and non-intervention rooms in the two facilities. Log transformation was applied to approximate normality of fungal measurements. Dehumidification with HEPA filtration was effective at controlling indoor dew point in both facilities and at reducing airborne culturable fungal spore levels in one of the two facilities. These preliminary results provide a scientific rationale for using this intervention in future studies designed to investigate the impact of indoor mold exposure on health outcomes. PRACTICAL IMPLICATIONS: Poor indoor air quality is a recognized cause or contributing factor to health effects. Dampness and humidity have been linked to upper and lower respiratory symptoms in children and adults. This study indicates that reducing indoor relative humidity and airborne mold spore levels using high-efficiency dehumidification units equipped with HEPA filtration is feasible even in work facilities such as day care centers where traffic in and out of the building is difficult to regulate. Clinicians should emphasize to their patients the importance of dehumidification and HEPA filtration to improve indoor air quality in the home and workplace.

Biomarkers in paediatric research and practice.

Children's health is, to a large extent, a function of their environment. Infectious agents remain the leading cause of death and disability in the world. In contrast, many of the new morbidities--asthma, intellectual impairments, behavioural problems, and cancer--are linked with industrial pollutants or other environmental influences. Our understanding of the risk factors for many diseases is incomplete, but it is widely recognised that disability and death result largely from interactions of environmental factors, broadly defined, and host susceptibility.

A side-by-side comparison of sampling methods for settled, indoor allergens.

Exposure to indoor allergens is associated with asthma, but there is no standardized sampling method for measuring allergens. We compared the association of measured allergen exposure and serum-specific IgE levels and the precision of three sampling methods (Cyclone, Mighty Mite, and Readivac II) to identify a standardized sampling method for indoor allergens. A random sample of 72 children, 5 to 17 years old, with doctor-diagnosed asthma who lived in the same residence >or=2 years were enrolled. Composite, side by side floor samples were obtained with all three methods. Dust allergen concentrations and serum-specific IgE levels were measured for Der f I, Fel d I, and Bla g I. Mean allergen concentration did not differ significantly by sampling method. Cat allergen was significantly correlated with serum-specific IgE for Cyclone (P=0.003) and Mighty Mite (P=0.008), but only marginally for Readivac II (P=0.07). Dust mite allergen was significantly correlated with serum-specific IgE for Readivac II (P=0.02) and Cyclone (P=0.038), but not for Mighty Mite (P=0.12). Cockroach allergen was not correlated with serum-specific IgE for any sampling method. In multiple linear regression, cat allergen was associated with serum-specific IgE for Cyclone (P=0.007) and Mighty Mite (P=0.02), but not for Readivac II (P=0.06). In contrast, dust mite allergen was marginally associated with serum-specific IgE for Readivac II (P=0.07), but not for Mighty Mite (P=0.64) or Cyclone (P=0.27). The Cyclone and Mighty Mite were more precise than Readivac II for cat allergen, but there was no difference for dust mite allergen (P>0.05). No single method is superior for measurement of indoor allergens. In general, cat allergen collected with the Cyclone was a better predictor of serum-specific IgE levels to Fel d I, whereas dust mite allergen collected with the Readivac II was a better predictor of serum-specific IgE levels to Der f I.

Contribution of residential exposures to asthma in us children and adolescents.

CONTEXT: Residential exposures are recognized risk factors for asthma, but the relative contribution of specific indoor allergens and their overall contribution to asthma among older children and adolescents in the United States are unknown. OBJECTIVE: To estimate the relative contributions, population-attributable risks, and costs of residential risk factors for doctor-diagnosed asthma. Design. Nationally representative, cross-sectional survey conducted from 1988 to 1994. SETTING AND PARTICIPANTS: A total of 5384 children who were 6 to 16 years old and participated in the National Health and Nutrition Examination Survey III, a survey of the health and nutritional status of children and adults in the United States. MAIN OUTCOME MEASURE: Doctor-diagnosed asthma, as reported by the parent. RESULTS: Five hundred three of 5384 children and adolescents (11.4%) had doctor-diagnosed asthma. After adjusting for age, gender, race, urban status, region of country, educational attainment of the head of household, and poverty, predictors of doctor-diagnosed asthma included a history of allergy to a pet (odds ratio [OR: 2.4; 95% confidence interval [CI]: 1.7, 3.3), presence of a pet in the household (OR: 1.5; 95% CI: 1.1, 2.1), and immediate hypersensitivity to dust mite (OR: 1.5; 95% CI: 1.05, 2.0), Alternaria (OR: 1.9; 95% CI: 1.3, 2.8), and cockroach allergens (OR: 1.4; CI: 1.04, 1.9). Family history of atopy (OR: 1.7; 95% CI: 1.1, 2.7) and diagnosis of allergic rhinitis (OR: 2.1; CI: 1.1, 3.7) were also predictors for asthma. The population-attributable risk of having 1 or more residential exposures associated with doctor-diagnosed asthma was 44.4% (95% CI: 29-60), or an estimated 2 million excess cases. The attributable cost of asthma resulting from residential exposures was $405 million (95% CI: $264-$547 million) annually. CONCLUSIONS: The elimination of identified residential exposures, if causally associated with asthma, would result in a 44% decline in doctor-diagnosed asthma among older children and adolescents in the United States.

Residential exposures associated with asthma in US children.

OBJECTIVE: Residential exposures are recognized risk factors for childhood asthma, but the relative contribution of specific risk factors and the overall contribution of housing to asthma in US children is unknown. The objective of this study was to identify risk factors and estimate the population attributable risk of residential exposures for doctor-diagnosed asthma for US children. METHODS: A cross-sectional survey was conducted from 1988 to 1994. Survey participants were 8257 children who were <6 years old and who participated in the Third National Health and Nutrition Examination Survey, a survey of the health and nutritional status of children and adults in the United States. The main outcome measure was doctor-diagnosed asthma, as reported by the parent. RESULTS: Six percent of children had doctor-diagnosed asthma. The prevalence of asthma was higher among boys (6.7%) than girls (5.1%) and was higher among black children (8.9%) than white children (5.2%). Risk factors for doctor-diagnosed asthma included a family history of atopy (odds ratio [OR]: 2.2; 95% confidence interval [CI]: 1.5, 3.1), child's history of allergy to a pet (OR: 24.2; 95% CI: 8.4, 69.5), exposure to environmental tobacco smoke (OR: 1.8; 95% CI: 1.2-2.6), use of a gas stove or oven for heat (OR: 1.8; 95% CI: 1.02-3.2), and presence of a dog in the household (OR: 1.6; 95% CI: 1.1, 2.3). The population attributable risk of >/=1 residential exposure for doctor-diagnosed asthma in US children <6 years old was 39.2%, or an estimated 533 000 excess cases, whereas having a family history of atopy accounted for 300 000. The attributable cost of asthma as a result of residential exposures for children <6 years old was $402 million (95% CI: $296-$507 million) annually. CONCLUSIONS: The elimination of identified residential risk factors, if causally associated with asthma, would result in a 39% decline in doctor-diagnosed asthma among US children <6 years old.

Trends and patterns of playground injuries in United States children and adolescents.

OBJECTIVE: To determine the prevalence, trends, and severity of injuries attributable to playground falls relative to other common unintentional mechanisms that resulted in an emergency department (ED) visit in the United States. DESIGN AND SETTING: Data from the emergency subset of the National Hospital Ambulatory Medical Care Survey collected from 1992 to 1997 for children <20 years. METHODS: Injury rates and 95% confidence intervals (CIs) were estimated and injury severity scores were computed. RESULTS: There were 920551 (95% CI: 540803 to 1300299) ED visits over the 6-year study period by children and adolescents that were attributable to falls from playground equipment. The annual incidence of visits for playground injuries did not significantly decrease over the course of the study (187000 to 98000, P =.053). Injury visits for playground falls were twice as prevalent as pedestrian mechanisms, but they were less prevalent than visits for motor vehicle-- and bicycle-related injuries. A larger proportion of playground falls resulted in "moderate-to-severe" injury than did bicycle or motor vehicle injuries. Children aged 5 to 9 years had the highest number of playground falls (P =.0014). Playground falls were most likely to occur at school compared to home, public, and other locations (P =.0016). CONCLUSIONS: Playground injury emergency visits have not significantly declined and remain a common unintentional mechanism of injury. Injury visits for playground falls were proportionally more severe than injury visits attributable to other common unintentional mechanisms. Interventions targeting schools and 5- to 9-year-old children may have the greatest impact in reducing emergency visits for playground injuries.

Long-term effect of dust control on blood lead concentrations.

BACKGROUND: Dust control is recommended to prevent children's exposure to residential lead hazards, but the long-term effect of dust control on children's exposure to environmental lead is unknown. OBJECTIVE: To determine the effect of dust control on children's exposure to lead, as measured by blood lead concentration at 48 months of age. DESIGN: A randomized, controlled trial. Setting. Rochester, New York. PARTICIPANTS: A total of 275 urban children were randomized at 6 months of age; 189 (69%) were available for the 48-month follow-up blood test. Intervention. Children and their families were randomly assigned to an intervention group that received cleaning equipment and up to 8 visits by a trained lead hazard control advisor or to a control group. The intervention was terminated when the children were 24 months of age. OUTCOME MEASURES: Geometric mean blood lead concentration and prevalence of elevated blood lead concentration (ie, >/=10 microg/dL, >/=15 microg/dL, and >/=20 microg/dL), by group assignment. RESULTS: For children with 48-month blood tests, baseline geometric mean blood lead concentrations were 2.8 microg/dL (95% confidence interval [CI]: 2.6, 3.0); there were no significant differences in baseline characteristics or lead exposure by group assignment. At 48 months of age, the geometric mean blood lead was 5.9 microg/dL (95% CI: 5.3, 6.7) for the intervention group and 6.1 microg/dL (95% CI: 5.5,6.9) for the control group. The percentage of children with a 48-month blood lead >/=10 microg/dL, >/=15 microg/dL, and >/=20 microg/dL was 19% versus 19%, 2% versus 9%, and 1% versus 2% in the intervention and control groups, respectively. CONCLUSIONS: We conclude that dust control, as performed by families and in the absence of lead hazard controls to reduce ongoing contamination from lead-based paint, was not effective in preventing children's exposure to residential lead hazards.

Barriers to asthma care in urban children: parent perspectives.

BACKGROUND: Despite improved treatment regimens for asthma, the prevalence and morbidity from asthma are increasing, especially among underserved, minority children. OBJECTIVE: The purpose of this study was to identify barriers to the treatment of asthma among urban, minority children as perceived by parents. METHODS: Parents were recruited from 4 schools located in low-income, urban areas with high rates of asthma hospitalizations. Focus groups involving parents of children 5 to 12 years old with asthma were conducted using a standardized questionnaire. Parents' comments were analyzed to identify barriers, and 3 independent raters coded parents' comments to assess reliability of interpretation. RESULTS: Forty parents who represented 47 children participated in the focus groups. All parents described their racial background as black. Parents' average age was 36.8 years, 92% were females, 70% were nonmarried, and 38% had less than a high school education. Forty-five percent of children had intermittent or mild asthma and 55% had moderate to severe asthma. The most frequent types of barriers identified by parents were patient or family characteristics (43%), followed by environmental (28%), health care provider (18%), and health care system (11%). Parents were specifically concerned about the use, safety and long-term complications of medications, the impact of limitation of exercise on their child's quality of life, and their own quality of life. CONCLUSIONS: In contrast with the widespread beliefs that access to medical care, health insurance, and continuity of care are the major barriers to quality asthma care, the barriers most frequently reported by parents were related to patient and family characteristics, health beliefs, or to their social and physical environment. To improve asthma management and health outcomes for urban, minority children with asthma, it is critical to tailor education about asthma and its treatment, and address quality of life issues for both children and parents.

Childhood injuries and deaths due to falls from windows.

BACKGROUND: Unintentional injuries are the leading cause of death in children, and falls are the most common type of unintentional injury in the US. The incidence of falls from windows, a common cause of death in urban areas, has not been described outside major cities such as New York and Chicago, and rates in urban and suburban areas have not been compared. OBJECTIVE: To estimate the incidence and identify the population at risk for falls from windows among children in Hamilton County, Ohio. DESIGN: Retrospective case series identified using Cincinnati Children's Hospital Medical Center (CHMC) Trauma Registry. SETTING: Hamilton County, Ohio, which has urban and nonurban areas. PARTICIPANTS: Children less than 15 years old residing in Hamilton County, Ohio, presenting to CHMC in Cincinnati, Ohio, after a fall from a window between January 1, 1991, and December 31, 1997. OUTCOME MEASURE: Annual incidence by age, race, gender, and residence of those who fell from windows. RESULTS: Over the 7-year study period, 86 (6.3%) of 1,363 falls were from windows. The mortality rate for falls from windows was 4.7%, compared to 0.07% for all other falls presenting to CHMC (P<.0001). Children 0-4 years old had a higher rate of falls than children aged 5-14 (14.6/100,000 vs. 2.0/100,000) (P<.0001). Males were twice as likely to fall as females (P<.016), and black children were three times more likely to fall than non-black children (P<.002). The incidence of falls in the city of Cincinnati was four times that of the non-urban area (P<.0002). CONCLUSIONS: Injuries from falls from windows are a public health problem in Hamilton County, Ohio, especially for young, urban children.

Program directors' perspectives on federally funded fellowship training in primary care research.

PURPOSE: To describe the organization, models of training, and institutional impact of National Research Service Award fellowship programs in primary care research. METHOD: Survey of 25 directors of currently-funded and former training sites. RESULTS: Twenty-four program directors (96%) completed the survey. Programs allocated 39% of fellows' time to course work leading to an advanced degree or other didactic instruction, and 40% of time to the conduct of research. Collaborations with other training programs within the institution occurred at 83% of sites. Programs commonly (54%) or exclusively (42%) relied on a research model of "early research independence" in which the fellow defined an area of research interest, rather than an "apprenticeship" model in which the fellow worked in a senior investigator's research area. These programs enriched the local academic environment, but required extensive financial subsidies. The high costs of training often had adverse impacts on recruitment and other components of the training process. CONCLUSION: Research training programs in primary care often substitute acquisition of advanced degrees for early immersion in research. The "early independence" model of research differs from fellowships in the medical specialties, and requires further study to assess its effectiveness. The need to subsidize training costs poses substantial problems for the institutions that host these fellowship programs.

Cognitive deficits associated with blood lead concentrations <10 microg/dL in US children and adolescents.

OBJECTIVE: Lead is a confirmed neurotoxicant, but the lowest blood lead concentration associated with deficits in cognitive functioning and academic achievement is poorly defined. The purpose of the present study was to examine the relationship of relatively low blood lead concentrations-especially concentrations <10 micrograms per deciliter (microg/dL)--with performance on tests of cognitive functioning in a representative sample of US children and adolescents. METHODS: The authors used data from the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988 to 1994, to assess the relationship between blood lead concentration and performance on tests of arithmetic skills, reading skills, nonverbal reasoning, and short-term memory among 4,853 children ages 6-16 years. RESULTS: The geometric mean blood lead concentration for children n the study sample was 1.9 microg/dL; 172 (2.1%) had blood lead concentrations > or =10 microg/dL. After adjustment for gender, race/ethnicity, poverty, region of the country, parent or caregiver's educational level, parent or caregiver's marital status parent, serum ferritin level, and serum cotinine level, the data showed an inverse relationship between blood lead concentration and scores on four measures of cognitive functioning. For every 1 microg/dL increase in blood lead concentration, there was a 0.7-point decrement in mean arithmetic scores, an approximately 1-point decrement in mean reading scores, a 0.1-point decrement in mean scores on a measure of nonverbal reasoning, and a 0.5-point decrement in mean scores on a measure of short-term memory. An inverse relationship between blood lead concentration and arithmetic and reading scores was observed for children with blood lead concentrations lower than 5.0 microg/dL. CONCLUSION: Deficits in cognitive and academic skills associated with lead exposure occur at blood lead concentrations lower than 5 microg/dL.

Physiologic stability of newborns during cup- and bottle-feeding.

BACKGROUND: To prevent breastfeeding problems, cup-feeding has been recommended as a method of providing medically necessary supplemental feedings to breastfed infants. OBJECTIVES: To compare amounts ingested, administration time, and infant physiologic stability during cup-, bottle-, and breastfeeding. DESIGN/METHODS: A total of 98 term, healthy newborns were randomized to either cup-feeding (n = 51) or bottle-feeding (n = 47). The heart (HR), respiratory (RR), and oxygen (O(2)) saturation rates were monitored on these infants and 25 breastfed newborns during 1 feeding. Differences in amounts ingested and administration times were evaluated with t tests and physiologic data with repeat measures analysis of variance. RESULTS: There were no significant differences in administration time, amounts ingested or overall HR, RR, and (O(2)) saturation rates, between cup and bottle groups. Breastfed infants had longer administration times and lower overall HR, RR, and higher O(2) saturation as compared with cup- and bottle-fed infants. CONCLUSIONS: Administration times, amounts ingested, and infant physiologic stability do not differ with cup- and bottle-feeding. Breastfeeding takes longer than cup- or bottle-feeding, but infants experience less physiologic variability. These data support cup-feeding as an alternative to bottle-feeding for supplying supplements to breastfed infants.

Association of dental caries and blood lead levels.

CONTEXT: Experiments show that dental caries rates are higher among lead-exposed animals, but this association has not been established in humans. OBJECTIVE: To examine the relationship between blood lead levels and dental caries. DESIGN: Cross-sectional survey conducted from 1988 to 1994 that included a dental examination and venipuncture blood lead assay. SETTING AND PARTICIPANTS: A total of 24901 persons aged 2 years and older who participated in the Third National Health and Nutrition Examination Survey, which assessed the health and nutritional status of children and adults in the United States. MAIN OUTCOME MEASURES: For children aged 2 to 11 years, the sum of decayed and filled deciduous or primary surfaces; for persons aged 6 years and older, the sum of decayed and filled permanent surfaces; for those 12 years and older, the sum of decayed, missing, and filled surfaces. RESULTS: The log of blood lead level was significantly associated with the number of affected surfaces for both deciduous and permanent teeth in all age groups, even after adjusting for sociodemographic characteristics, diet, and dental care. Among children aged 5 to 17 years, a 0.24-micromol/L (5-microg/dL) change in blood lead level was associated with an elevated risk of dental caries (odds ratio, 1.8; 95% confidence interval, 1.3-2.5). Differences in blood lead level explained some of the differences in caries prevalence in different income levels and regions of the United States. We estimated the population attributable risk of lead exposure to be 13.5% and 9.6% of dental caries occurring in 5- to 17-year-olds exposed to the high and moderate levels, respectively. CONCLUSIONS: Environmental lead exposure is associated with an increased prevalence of dental caries in the US population. Findings may help explain the distribution of caries by income and region of the United States.

Primary prevention of childhood lead exposure: A randomized trial of dust control.

BACKGROUND: Dust control is recommended as one of the primary strategies to prevent or control children's exposure to residential lead hazards, but the effect of dust control on children's blood lead levels is poorly understood. OBJECTIVE: To determine the effectiveness of dust control in preventing children's exposure to lead, as measured by blood lead levels, during their peak age of susceptibility. DESIGN: A randomized, controlled trial. SETTING: Rochester, NY. PARTICIPANTS: A total of 275 urban children were randomized at 6 months of age, of whom 246 (90%) were available for the 24-month-old follow-up visit. INTERVENTIONS: Children and their families were randomly assigned to an intervention group (n = 140), which received cleaning equipment and up to eight visits by a dust control advisor, or a control group (n = 135). OUTCOME MEASURES: Geometric mean blood lead levels and prevalence of elevated blood lead levels (ie, >10 microg/dL, 15 microg/dL, and 20 microg/dL). RESULTS: At baseline, children's geometric mean blood lead levels were 2.9 microg/dL (95% confidence interval [CI] = 2.7, 3.1); there were no significant differences in characteristics or lead exposure by group assignment, with the exception of water lead levels. For children in the intervention group, the mean number of visits by a dust control advisor during the 18-month study period was 6.2; 51 (36%) had 4 to 7 visits, and 69 (49%) had 8 visits. At 24 months of age, the geometric mean blood lead was 7.3 microg/dL (95% CI = 6.6, 8.2) for the intervention group and 7.8 microg/dL (95% CI = 6.9, 8. 7) for the control group. The percentage of children with a 24-month blood lead >/=10 microg/dL, >/=15 microg/dL, and >/=20 microg/dL was 31% versus 36%, 12% versus 14%, and 5% versus 7% in the intervention and control groups, respectively. CONCLUSIONS: We conclude that dust control, as performed by families and in the absence of lead hazard controls to reduce ongoing contamination from lead-based paint, is not effective in the primary prevention of childhood lead exposure.

The effects of early pacifier use on breastfeeding duration.

OBJECTIVE: To evaluate the effects of pacifier use and the timing of pacifier introduction on breastfeeding duration, problems, and frequency. METHODS: A cohort of 265 breastfeeding mother-infant dyads was followed prospectively. Maternal interviews were conducted at delivery, 2, 6, 12, and 24 weeks, and thereafter every 90 days until breastfeeding ended. Information was obtained regarding pacifier use, infant feeding, use of supplemental foods and breastfeeding frequency, duration, and problems. The effect of pacifier introduction by 6 weeks of age on breastfeeding duration was evaluated with Kaplan-Meier and Cox proportional hazards models. The effect of the timing of pacifier introduction (

Efficacy of informational letters on hepatitis B immunization rates in university students.

A randomized, controlled trial was conducted at a private university to determine whether students who received an informational letter (n = 366) would be more likely to receive a hepatitis B vaccination than students in a control group (n = 366). Surveys were conducted to determine the students' reasons for deciding to be vaccinated. Rates of hepatitis B immunization were significantly higher among students assigned to the intervention group (10.7%) than among the control group (1.9%). Vaccinated students were more likely than unvaccinated students to report having had 3 or more sexual partners in the past 6 months. Students at higher risk for hepatitis B infection were more likely than others to be vaccinated. Although the overall rate of immunization was low, informational letters about the hepatitis B virus and vaccine were found to be efficacious in increasing hepatitis B immunization rates among students in the setting of a concurrent educational campaign.