Response to: "What is the meaning of non-linear dose-response relationships between blood lead concentrations and IQ?".
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Dose-Response Relationship, Drug↗
Biomedical subjects
Charles R Henderson
Publications and source records attributed to Charles R Henderson.
Reducing the impact of uncontrollable stressful life events through a program of nurse home visitation for new parents.
The current study examined whether the Nurse Family Partnership (NFP), an intervention in which mothers received home visitation by registered nurses pre- and postnatally, reduced mothers' vulnerability to the effects of stressful life events several years after the program was completed. Data from a randomized trial of the NFP were examined for mothers (N = 324) who were generally low-income, young, and unmarried at the time of the birth of their first child. Structured interviews were done with mothers about 15 years after the program began. Results showed that experiencing uncontrollable stressful life events, such as the death of a loved one, led to fewer negative outcomes (fewer mental health problems, less binge drinking, and better parenting practices) among nurse-visited mothers than among mothers receiving no visitation. Furthermore, the program's effect on reducing vulnerability to the negative impact of life events was particularly evident among parents who were younger or had a lower sense of personal control at intake. These findings suggest that, in addition to preventing the occurrence of negative outcomes that were direct targets of the intervention, the NFP more generally enhanced mothers' ability to cope with future stressful life events.
Adult↗
Comments on "Recent developments in low-level lead exposure and intellectual impairment in children".
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Child Development↗
Effects of home visits by paraprofessionals and by nurses: age 4 follow-up results of a randomized trial.
OBJECTIVE: To examine the effects of prenatal and infancy home visiting by paraprofessionals and by nurses from child age 2 through age 4 years. METHODS: We conducted, in public and private care settings in Denver, Colorado, a randomized, controlled trial with 3 arms, ie, control, paraprofessional visits, and nurse visits. Home visits were provided from pregnancy through child age 2 years. We invited 1178 consecutive, low-income, pregnant women with no previous live births to participate, and we randomized 735; 85% were unmarried, 47% Mexican American, 35% white non-Mexican American, 15% black, and 3% American Indian/Asian. Outcomes consisted of maternal reports of subsequent pregnancies, participation in education and work, use of welfare, marriage, cohabitation, experience of domestic violence, mental health, substance use, and sense of mastery; observations of mother-child interaction and the home environment; tests of children's language and executive functioning; and mothers' reports of children's externalizing behavior problems. RESULTS: Two years after the program ended, women who were visited by paraprofessionals, compared with control subjects, were less likely to be married (32.2% vs 44.0%) and to live with the biological father of the child (32.7% vs 43.1%) but worked more (15.13 months vs 13.38 months) and reported a greater sense of mastery and better mental health (standardized scores [mean = 100, SD = 10] of 101.25 vs 99.31 and 101.21 vs 99.16, respectively). Paraprofessional-visited women had fewer subsequent miscarriages (6.6% vs 12.3%) and low birth weight newborns (2.8% vs 7.7%). Mothers and children who were visited by paraprofessionals, compared with control subjects, displayed greater sensitivity and responsiveness toward one another (standardized score [mean = 100, SD = 10] of 100.92 vs 98.66) and, in cases in which the mothers had low levels of psychologic resources at registration, had home environments that were more supportive of children's early learning (score of 24.63 vs 23.35). Nurse-visited women reported greater intervals between the births of their first and second children (24.51 months vs 20.39 months) and less domestic violence (6.9% vs 13.6%) and enrolled their children less frequently in preschool, Head Start, or licensed day care than did control subjects. Nurse-visited children whose mothers had low levels of psychologic resources at registration, compared with control group counterparts, demonstrated home environments that were more supportive of children's early learning (score of 24.61 vs 23.35), more advanced language (score of 91.39 vs 86.73), superior executive functioning (score of 100.16 vs 95.48), and better behavioral adaptation during testing (score of 100.41 vs 96.66). There were no statistically significant effects of either nurse or paraprofessional visits on the number of subsequent pregnancies, women's educational achievement, use of substances, use of welfare, or children's externalizing behavior problems. CONCLUSIONS: Paraprofessional-visited mothers began to experience benefits from the program 2 years after the program ended at child age 2 years, but their first-born children were not statistically distinguishable from their control group counterparts. Nurse-visited mothers and children continued to benefit from the program 2 years after it ended. The impact of the nurse-delivered program on children was concentrated on children born to mothers with low levels of psychologic resources.
Birth Intervals↗
Effects of nurse home-visiting on maternal life course and child development: age 6 follow-up results of a randomized trial.
OBJECTIVE: To test, with an urban, primarily black sample, the effects of prenatal and infancy home visits by nurses on mothers' fertility and economic self-sufficiency and the academic and behavioral adjustment of their children as the children finished kindergarten, near their sixth birthday. METHODS: We conducted a randomized, controlled trial of a program of prenatal and infancy home-visiting in a public system of obstetric and pediatric care in Memphis, Tennessee. A total of 743 primarily black women at <29 weeks of gestation, with no previous live births and with > or =2 sociodemographic risk characteristics (unmarried, <12 years of education, or unemployed), were randomly assigned to receive nurse home visits or comparison services. Outcomes consisted of women's number and timing of subsequent pregnancies, months of employment, use of welfare, food stamps, and Medicaid, educational achievement, behavioral problems attributable to the use of substances, rates of marriage and cohabitation, and duration of relationships with partners and their children's behavior problems, responses to story stems, intellectual functioning, receptive language, and academic achievement. RESULTS: In contrast to counterparts assigned to the comparison group, women visited by nurses had fewer subsequent pregnancies and births (1.16 vs 1.38 pregnancies and 1.08 vs 1.28 births, respectively), longer intervals between births of the first and second children (34.28 vs 30.23 months), longer relationships with current partners (54.36 vs 45.00 months), and, since the previous follow-up evaluation at 4.5 years, fewer months of using welfare (7.21 vs 8.96 months) and food stamps (9.67 vs 11.50 months). Nurse-visited children were more likely to have been enrolled in formal out-of-home care between 2 and 4.5 years of age (82.0% vs 74.9%). Children visited by nurses demonstrated higher intellectual functioning and receptive vocabulary scores (scores of 92.34 vs 90.24 and 84.32 vs 82.13, respectively) and fewer behavior problems in the borderline or clinical range (1.8% vs 5.4%). Nurse-visited children born to mothers with low levels of psychologic resources had higher arithmetic achievement test scores (score of 88.61 vs 85.42) and expressed less aggression (score of 98.58 vs 101.10) and incoherence (score of 20.90 vs 29.84) in response to story stems. There were no statistically significant program effects on women's education, duration of employment, rates of marriage, being in a partnered relationship, living with the father of the child, or domestic violence, current partner's educational level, or behavioral problems attributable to the use of alcohol or drugs. CONCLUSION: This program of prenatal and infancy home-visiting by nurses continued to improve the lives of women and children at child age 6 years, 4 years after the program ended.
Adolescent↗
Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter.
BACKGROUND: Despite dramatic declines in children's blood lead concentrations and a lowering of the Centers for Disease Control and Prevention's level of concern to 10 microg per deciliter (0.483 micromol per liter), little is known about children's neurobehavioral functioning at lead concentrations below this level. METHODS: We measured blood lead concentrations in 172 children at 6, 12, 18, 24, 36, 48, and 60 months of age and administered the Stanford-Binet Intelligence Scale at the ages of 3 and 5 years. The relation between IQ and blood lead concentration was estimated with the use of linear and nonlinear mixed models, with adjustment for maternal IQ, quality of the home environment, and other potential confounders. RESULTS: The blood lead concentration was inversely and significantly associated with IQ. In the linear model, each increase of 10 microg per deciliter in the lifetime average blood lead concentration was associated with a 4.6-point decrease in IQ (P=0.004), whereas for the subsample of 101 children whose maximal lead concentrations remained below 10 microg per deciliter, the change in IQ associated with a given change in lead concentration was greater. When estimated in a nonlinear model with the full sample, IQ declined by 7.4 points as lifetime average blood lead concentrations increased from 1 to 10 microg per deciliter. CONCLUSIONS: Blood lead concentrations, even those below 10 microg per deciliter, are inversely associated with children's IQ scores at three and five years of age, and associated declines in IQ are greater at these concentrations than at higher concentrations. These findings suggest that more U.S. children may be adversely affected by environmental lead than previously estimated.
Child, Preschool↗
Low-level lead exposure, executive functioning, and learning in early childhood.
The current paper presents evidence relating low-level lead exposure to impaired executive functioning in young children. Using the Shape School task, we assessed focused attention, attention switching, working memory, and the ability to inhibit automatic responses in a cohort of 170 children. Participants performed the Shape School task at both 48 and 54 months of age; the mean blood lead level was 6.49 microg/dl at 48 months. After controlling for a wide range of sociodemographic, prenatal, and perinatal variables, blood lead level was negatively associated with children's focused attention while performing the tasks, efficiency at naming colors, and inhibition of automatic responding. In addition, children with higher blood lead levels completed fewer phases of the task and knew fewer color and shape names. There was no association between blood lead and performance on the most difficult tasks, those requiring attention switching or the combination of inhibition and switching. Children's IQ scores were strongly associated with blood lead and Shape School performance, and when entered as a covariate, only color knowledge and the number of tasks completed remained significant. Results provide only weak support for impaired executive functioning, but the deficits in color knowledge may indicate a primary sensory deficit or difficulty with forming conditional associations, both implicating disruptions in dopamine system function.
Attention↗
A cooperative communication intervention for nursing home staff and family members of residents.
PURPOSE: This article reports on a randomized, controlled study of Partners in Caregiving, an intervention designed to increase cooperation and effective communication between family members and nursing home staff. DESIGN AND METHODS: Participants included 932 relatives and 655 staff members recruited from 20 nursing homes, randomly assigned to treatment and control conditions. Parallel training sessions on communication and conflict resolution techniques were conducted with the family and staff in the treatment group, followed by a joint meeting with facility administrators. RESULTS: Positive outcomes were found for both family and staff members in the treatment group. Both groups showed improved attitudes toward each other, families of residents with dementia reported less conflict with staff, and staff reported a lower likelihood of quitting. IMPLICATIONS: Multiple studies report significant interpersonal stress between family members of nursing home residents and facility staff members. Partners in Caregiving appears to be an effective way to improve family-staff relationships in nursing homes.
Adult↗
Home visiting by paraprofessionals and by nurses: a randomized, controlled trial.
OBJECTIVE: To examine the effectiveness of home visiting by paraprofessionals and by nurses as separate means of improving maternal and child health when both types of visitors are trained in a program model that has demonstrated effectiveness when delivered by nurses. METHODS: A randomized, controlled trial was conducted in public- and private-care settings in Denver, Colorado. One thousand one hundred seventy-eight consecutive pregnant women with no previous live births who were eligible for Medicaid or who had no private health insurance were invited to participate. Seven hundred thirty-five women were randomized to control, paraprofessional, or nurse conditions. Nurses completed an average of 6.5 home visits during pregnancy and 21 visits from birth to the children's second birthdays. Paraprofessionals completed an average of 6.3 home visits during pregnancy and 16 visits from birth to the children's second birthdays. The main outcomes consisted of changes in women's urine cotinine over the course of pregnancy; women's use of ancillary services during pregnancy; subsequent pregnancies and births, educational achievement, workforce participation, and use of welfare; mother-infant responsive interaction; families' home environments; infants' emotional vulnerability in response to fear stimuli and low emotional vitality in response to joy and anger stimuli; and children's language and mental development, temperament, and behavioral problems. RESULTS: Paraprofessional-visited mother-child pairs in which the mother had low psychological resources interacted with one another more responsively than their control-group counterparts (99.45 vs 97.54 standard score points). There were no other statistically significant paraprofessional effects. In contrast to their control-group counterparts, nurse-visited smokers had greater reductions in cotinine levels from intake to the end of pregnancy (259.0 vs 12.32 ng/mL); by the study child's second birthday, women visited by nurses had fewer subsequent pregnancies (29% vs 41%) and births (12% vs 19%); they delayed subsequent pregnancies for longer intervals; and during the second year after the birth of their first child, they worked more than women in the control group (6.83 vs 5.65 months). Nurse-visited mother-child pairs interacted with one another more responsively than those in the control group (100.31 vs 98.99 standard score points). At 6 months of age, nurse-visited infants, in contrast to their control-group counterparts, were less likely to exhibit emotional vulnerability in response to fear stimuli (16% vs 25%) and nurse-visited infants born to women with low psychological resources were less likely to exhibit low emotional vitality in response to joy and anger stimuli (24% vs 40% and 13% vs 33%). At 21 months, nurse-visited children born to women with low psychological resources were less likely to exhibit language delays (7% vs 18%); and at 24 months, they exhibited superior mental development (90.18 vs 86.20 Mental Development Index scores) than their control-group counterparts. There were no statistically significant program effects for the nurses on women's use of ancillary prenatal services, educational achievement, use of welfare, or their children's temperament or behavior problems. For most outcomes on which either visitor produced significant effects, the paraprofessionals typically had effects that were about half the size of those produced by nurses. CONCLUSIONS: When trained in a model program of prenatal and infancy home visiting, paraprofessionals produced small effects that rarely achieved statistical or clinical significance; the absence of statistical significance for some outcomes is probably attributable to limited statistical power to detect small effects. Nurses produced significant effects on a wide range of maternal and child outcomes.
Female↗