Elsevier

Early Human Development

Volume 115, December 2017, Pages 82-87
Early Human Development

Special health care needs explains the effect of extremely low birth weight on math but not language achievement

https://doi.org/10.1016/j.earlhumdev.2017.09.019Get rights and content

Highlights

  • Extremely low birth weight (ELBW) adolescents have risk for poor academic achievement compared to normal birth weight peers.

  • Having special health care needs (SHCN) is associated with poor achievement among NBW children.

  • Birth weight alone explains only half of the effect of ELBW on math achievement.

  • Having SHCN appears to both modify and mediate this effect.

Abstract

Objectives

Extremely low birth weight (ELBW; < 1 kg) adolescents are at risk for special health care needs (SHCN) and poor math achievement compared to normal birth weight (NBW) peers. SHCN are associated with poor academic achievement among NBW children. We hypothesize that SHCN explain the effect of ELBW on math achievement.

Methods

We compared age 14 Woodcock-Johnson Calculation standard scores between 181 ELBW infants and 115 NBW controls. Persistent SHCN included: 1) prescription medication or equipment use, 2) subspecialty or therapeutic service use, or 3) hospitalization. We used nonlinear marginal effects models to decompose the total effect of ELBW on math into the following 4 components: the effect of ELBW controlling for SHCN, the effect of SHCN controlling for ELBW, effect modification by SHCN, and mediated interaction where SHCN is both causal mediator and effect modifier. Models were adjusted for sociodemographic factors.

Results

ELBW adolescents had lower mean math scores than NBW peers (81.3 vs. 96.4). SHCN were more common among ELBW adolescents (54.1% vs. 27%). The total effect of ELBW on math scores was − 15.7 points (95% CI − 21.0, − 10.5). The effect of birth weight alone was − 7.6 points (95% CI − 13.7, − 1.4); the effect of SHCN alone was negligible. SHCN interaction and mediated interaction effects each accounted for 25% of the total effect.

Conclusions

Birth weight alone explains only half of the effect of ELBW on math achievement. We found evidence of effect modification and mediation by SHCN. Understanding these explanatory pathways may lead to targeted interventions for improved outcomes.

Introduction

Adolescents born at extremely low birth weight (ELBW, < 1000 g) have poor academic achievement compared to term born normal birth weight (NBW) children [1], [2], [3], [4], [5], [6]. Data also indicate significantly worse functional outcomes for ELBW survivors related to higher rates of chronic respiratory disease and neurosensory impairment [4], [7]. Our group recently reported the persistence of high rates of special health care needs (SHCN) into adolescence, with 74% having an identified chronic condition at 14 years [8]. In fact, the odds of having a SHCN at age 14 was 2.8 (95% CI = 1.7, 4.6) among ELBW adolescents compared to NBW peers.

The relationship between SHCN and school achievement has focused primarily on asthma, diabetes, and epilepsy and found a negative impact of chronic illness on achievement [9]. A meta-analysis revealed that children with diabetes suffer a disadvantage at school and have cognitive and executive function problems [10]. Another meta-analysis revealed that children with severe asthma diagnoses had poorer academic achievement than healthier peers [11]. One recent study of school-age children in urban St. Louis revealed significant differences on academic achievement testing in those with severe asthma compared to milder forms [12].

Noting that ELBW adolescents are at increased risk for both poor academic achievement and SHCN related to chronic illnesses, one might hypothesize that SHCN play a causal role in poor achievement in this population. A recent study tested this relationship in a cohort of infants born < 2500 g. Those with SHCN at 8 years of age had significantly lower scores on academic achievement at age 18 compared to those without a SHCN [13]. As all study participants had low birth weight, it was not possible to examine interactional effects of birth weight and SHCN on achievement.

We aim to further understand the role of SHCN in explaining higher rates of academic underachievement among adolescents with ELBW. We hypothesize that having a SHCN modifies the relationship between low birth weight and poor achievement. Being agnostic as to the causal relationships under study, we tested the possibility that SHCN acts as a mediator, an effect modifier, or a mediated modifier of achievement among adolescents with ELBW.

Section snippets

Sample

Participants included the 238 survivors of 344 children born < 1 kg admitted to the Neonatal Intensive Care Unit (NICU) at Rainbow Babies and Children's Hospital, Cleveland, Ohio from 1992 through 1995. A NBW comparison group of 176 children born at term gestation (> 36 weeks by parent report) was recruited at 8 years from the same school as the ELBW child and of the same sex, race, and age within 3 months.

Two hundred and nineteen children (92%) were followed to age 8 years, 181 (83%) were followed to

Results

Participants at 14-year follow-up included 181 adolescents in the ELBW group (mean birth weight 815 ± 124 g) and 115 in the NBW group (mean birth weight 3260 ± 524 g). The groups did not differ by age, sex, race, or maternal education, marital status, or income (Table 1). Mothers of ELBW adolescents were on average older than mothers of NBW adolescents at time of follow-up (43.7 vs. 40.6, p < 0.05).

The proportion of children with persistent SHCN at 14 years was significantly different between birth

Discussion

Children born with ELBW are at increased risk for poor academic achievement and specific learning problems in math compared to NBW peers [20]. Adolescents with low birth weight were more likely to have SHCN compared to NBW controls and those with a SHCN have lower average scores on tests of achievement. Our decomposition analysis revealed a highly complex interrelationship among birth weight, SHCN, and achievement.

The effect of SHCN on academic achievement has not been widely studied among

Financial disclosure

The authors have no financial relationships relevant to this article to disclose.

Funding source

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Potential conflicts of interest

The authors have no conflicts of interest relevant to this article to disclose.

Author's statement

Dr. Hack supervised the study, had access to all of the data in the study, and assumed responsibility for the integrity of the data.

Drs. Hack, Taylor, and Litt developed the study concept and design.

Drs. Hack and Andreias acquired the data.

Drs. Litt and Taylor and Ms. Minich participated in the analysis, including statistical analysis and interpretation of the data.

Dr. Litt drafted the first version of the manuscript and all the co-authors participated in the critical revision of the manuscript

Acknowledgements

We thank Kathy Winter, who coordinated the project and participated in the interview of the parents; Laura Andreias, MD, MS, Ellen Durand, MA, and Heather Marcinick, MA, research assistants, who tested the children and administered the questionnaires; Sheree Hemphill, who developed the REDCap database; Lydia Cartar, MA, who participated in the initial data management and analysis; and Bonnie Tarantino and Alpher Torres, who provided clerical assistance.

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