Halting the Development of Physical Aggression in Females and Improving Academic Outcomes through the Nurse-Family Partnership Intervention

The 2001 Surgeon General's Report on Youth Violence states that while the prevalence of self-reported violence among adolescents has remained relatively constant from 1980 – 1998, these rates are still high with approximately 30% of high school seniors reporting having committed a violent act in the past year. Of additional concern is the fact that the prevalence of violence among females has markedly increased from 1983 to 1998. In 1983, the male:female violent incident ratio was 7.4 which decreased to 3.5 by 1998. Because the overall prevalence rates have remained relatively stable over that same time period, this decrease in the male:female violent incident ratio indicates that females are engaging in violent acts more frequently.

Numerous studies demonstrate that individuals exhibiting violence during adolescence and adulthood also had problems with aggressive behavior during childhood and that a high level of childhood aggression was an important predictor of both adolescent and adult aggression, including violent offending Research findings have shown that physically aggressive behavior begins to emerge during infancy, around the first year after birth, and steadily increases thereafter, peaking between 2 and 3 years of age. Rates of aggression are highest and fluctuate between 2-4 years of age and then decline as development proceeds. Children who were extremely high on physical aggression at age 2 have also been shown to remain high on physical aggression at 5 years of age. Studies have demonstrated that aggressive behavior is a significant predictor of grade retentions, suspensions, and academic failure. Given that some children enter kindergarten with a highly aggressive pattern of behavior already in place, intervention strategies need to begin prior to this age.

Parent intervention has become a major focus for prevention efforts and the programs have been shown to be most effective when implemented in early childhood. The Nurse-Family Partnership (NFP), an intensive nurse-home visiting program targets first-time, low income mothers and begins during pregnancy and continues until the child is two years old. The NFP has demonstrated consistent program effects on parenting behaviors and children's verbal ability, cognition, and executive function and is one of 11 programs identified by the Center for the Study and Prevention of Violence as a model program in its Blueprints for Violence Prevention initiative. The results of our path analyses presented at last year's conference demonstrated that among females, the NFP successfully reduced physical aggression at age 2 years which led to increased vocabulary scores at age 6. By age 6, however, the group differences in physical aggression scores were attenuated and the groups remained equivalent through age 12. We hypothesized that the lower peak physical aggression value exhibited by the nurse visited females during toddlerhood placed these girls on a different trajectory for later behavioral and academic outcomes then their comparison group counterparts. The purpose of these secondary analyses was to extend the previous path model and examine academic outcomes at 6th grade for the female sample. Office and home interviews and assessments were conducted when the target child was 6 and 12 months old, and 2, 4, 6, 9 and 12 years of age. Data from the age 2, 6, and 12 year assessment periods were used for these analyses.

Sample

Women less than 29 weeks pregnant were recruited from the obstetrical clinic at the Regional Medical Center in Memphis, Tennessee if they had no previous live births, no specific chronic illnesses thought to contribute to fetal growth retardation or preterm delivery, and at least 2 of the following sociodemographic risk conditions: unmarried, less than 12 years of education, and unemployed. Eighty-eight percent (1139/1290) of the women completed informed consent and were randomized to 1 of 4 treatment conditions (only groups 2 and 4 were followed postnatally). Ninety-two percent of the women enrolled were African American, 98% were unmarried, 64% were aged 18 or younger at registration, and 85% came from households with incomes at or below the federal poverty level. Compared with women who refused, those who agreed to participate were more likely to be African American than non-African American (89% vs. 74%, p<.001); younger (mean age 18 vs. 19 years, p=.001); and non-high school graduates (89% vs. 84%, p=.01). Only the female children who were followed postnatally and we obtained school record data for were used for these analyses yielding a sample size of 361.

Treatment conditions

Women were randomized to treatment groups by a computer program using methods that are extensions of those given by Soares and Wu. Randomization was conducted within strata from a model with 5 classification factors: maternal race, maternal age, gestational age at enrollment, employment status of the head of the household, and geographic region of residence. Women assigned to the home visitation groups were subsequently randomly assigned to a nurse home visitor.

Women in treatment group 1 (N=166) were provided free-roundtrip taxi-cab transportation for scheduled prenatal care appointments; they did not receive any postpartum services or assessments. Women in treatment group 2 (N=515) were provided free transportation for scheduled prenatal care and developmental screening and referral services for the child at ages 6, 12, and 24 months. Women in treatment group 3 (N=230) were provided the free transportation and screening services offered in treatment group 2 and also intensive nurse home visitation services during pregnancy, 1 postpartum visit in the hospital before discharge, and 1 postpartum visit in the home. Women in treatment group 4 (N=228) were provided the same services as those in treatment group 3 but also were visited by nurses until the child's second birthday. For the evaluation of postnatal outcomes, treatment group 2 was contrasted with treatment group 4 since only these groups were assessed after delivery of the child.

Nurse Home Visiting Intervention

The experimental home visitation program was carried out by the Memphis/Shelby County Health Department. The nurses completed an average of 7 home visits (range 0 – 18) during pregnancy and 26 home visits (range 0 – 71) during the first 2 years postpartum. The nurses followed a detailed visit-by-visit protocol to help women improve their health-related behaviors, care of their children, and life-course development (pregnancy planning, educational achievement, and participation in the workforce). The postpartum program protocols focused on helping mothers and other caregivers improve the physical and emotional care of their children. Specific curricula were integrated into the program to promote parent-child interaction by facilitating parents' understanding of their infants' and toddlers' communicative signals and enhancing interest in playing with their children in ways that promote emotional and cognitive development.

Dependent Variables

Physical Aggression. The three physical aggression items from the Child Behavior Checklist (CBCL, ages 2-3; Achenbach, 1992) were selected as the measure of physical aggression: “physically attacks others;” “hits others;” and “gets into fights”.

Child's Verbal ability – Age 6. The Peabody Picture Vocabulary Test – Revised was used to assess verbal ability at age 6. The PPVT-R measures a child's receptive vocabulary and is used as a screening tool for verbal ability.

6th Grade Average Math and Reading GPA. School records were abstracted and the final math and reading grades for 6th grade obtained. These grades were converted and the average GPA was created.

Number of Grade Retentions. From the school record abstractions, the number of grade retentions was computed form kindergarten through 6th grade.

Tennessee Comprehensive Assessment Program (TCAP). The Tennessee Comprehensive Assessment Program (TCAP) Achievement Test is a timed, multiple choice assessment that measures skills in Reading, Language Arts, Mathematics, Science and Social Studies. We obtained these data from the child's 6th grade school record.

Peabody Individual Achievement Test – Revised. The Peabody Individual Achievement Test (PIAT-R) is an individually administered, norm-referenced measure of academic achievement.

Leiter International Performance Scale – Revised (Leiter-R). The Leiter-R is a nonverbal test of intelligence and cognitive abilities and can used from age 2 years through 20.11 years. At our 12 year assessment, we administered only the Sustained Attention subscale of this instrument.

Results

The indirect effects of age 2 physical aggression and age 6 vocabulary on academic outcomes at age 12 are shown below in Table 1. None of the indirect effects of physical aggression on academic outcomes was significant at p<.10 for the comparison group females as the joint significance criterion was not met. Among nurse-visited females, however, decreases in physical aggression led to increased vocabulary scores which, in turn, led to higher GPA and assessment scores and fewer grade retentions. The joint significance test criteria was met (at p <.10) for each of the direct effects (age 6 vocabulary on age 2 physical aggression and age 12 academic outcomes on age 6 vocabulary) and the total direct and indirect effects were significant, as well.

Table 1. Path analyses for the indirect effects of age 2 physical aggression (PA) and age 6 vocabulary on academic outcomes at 12 years of age for nurse-visited and comparison group females*

Dependent Variable Beta SE p-Value

GPA

Nurse-visited -0.059 0.028 .056

Comparison 0.008 0.009 NS

TCAP Score

Nurse-visited -1.692 0.746 .039

Comparison 0.144 0.385 NS

# Grade Retentions

Nurse-Visited 0.031 0.016 .064

Comparison -0.001 0.004 NS

Leiter Sustained Attention

Nurse-visited -0.156 0.080 .066

Comparison 0.003 0.020 NS

PIAT-R Composite Reading

Nurse-visited -0.789 0.435 .097

Comparison 0.032 0.212 NS

PIAT-R Math

Nurse-visited -0.671 0.382 .096

Comparison 0.070 0.187 NS

* Adjusted for negative parenting attitudes, household poverty, maternal psychological resources, harsh parenting practices, Caldwell HOME score, and school benchmark scores for math and reading.

Discussion

Our results demonstrate that the NFP successfully halted the development of early physical aggression in females placing these girls on a different developmental pathway for improved academic outcomes 10 years after the intervention ended. Studies have shown that academic failure places adolescents at increased risk for involvement in crime, violence, and substance use and thus, the intervention may have successfully interrupted this negative chain of events.