Latent Class Analysis of Prenatal Substance Exposure and Child Behavioral Outcomes.

OBJECTIVES: To predict behavioral disruptions in middle childhood, we identified latent classes of prenatal substance use. STUDY DESIGN: As part of the Environmental influences on Child Health Outcomes Program, we harmonized prenatal substance use data and child behavior outcomes from 2195 women and their 6- to 11-year-old children across 10 cohorts in the US and used latent class-adjusted regression models to predict parent-rated child behavior. RESULTS: Three latent classes fit the data: low use (90.5%; n = 1986), primarily using no substances; licit use (6.6%; n = 145), mainly using nicotine with a moderate likelihood of using alcohol and marijuana; and illicit use (2.9%; n = 64), predominantly using illicit substances along with a moderate likelihood of using licit substances. Children exposed to primarily licit substances in utero had greater levels of externalizing behavior than children exposed to low or no substances (P = .001, d = .64). Children exposed to illicit substances in utero showed small but significant elevations in internalizing behavior than children exposed to low or no substances (P < .001, d = .16). CONCLUSIONS: The differences in prenatal polysubstance use may increase risk for specific childhood problem behaviors; however, child outcomes appeared comparably adverse for both licit and illicit polysubstance exposure. We highlight the need for similar multicohort, large-scale studies to examine childhood outcomes based on prenatal substance use profiles.

Prevalence and neonatal factors associated with autism spectrum disorders in preterm infants.

OBJECTIVES: To determine the prevalence of autism spectrum disorders (ASD) across gestational age, examine the risk of ASD by gestational age controlling for other risk factors, and identify potential risk factors in the neonatal intensive care unit. STUDY DESIGN: A retrospective cohort of infants born at ≥ 24 weeks between January 1, 2000, and December 31, 2007 at 11 Kaiser Permanente Northern California hospitals (n = 195,021). ASD cases were defined by a diagnosis made at a Kaiser Permanente ASD evaluation center, by a clinical specialist, or by a pediatrician. Cox proportional hazards regression models were used to evaluate the association between gestational age and ASD as well as potential risk factors in the neonatal intensive care unit and ASD. RESULTS: The prevalence of ASD in infants <37 weeks was 1.78% compared with 1.22% in infants born ≥ 37 weeks (P < .001). Compared with term infants, infants born at 24-26 weeks had an adjusted hazard ratio (HR) for a diagnosis of ASD of 2.7 (95% CI 1.5-5.0). Infants born at 27-33 weeks (adjusted HR 1.4, 95% CI 1.1-1.8) and 34-36 weeks (adjusted HR 1.3, 95% CI 1.1-1.4) were also at increased risk. High frequency ventilation and intracranial hemorrhage were associated with ASD in infants < 34 weeks. CONCLUSIONS: ASD was ~ 3 times more prevalent in infants <27 weeks compared with term infants. Each week of shorter gestation was associated with an increased risk of ASD. High frequency ventilation and intracranial hemorrhage were associated with ASD among infants <34 weeks.

Trends in severe bronchopulmonary dysplasia rates between 1994 and 2002.

OBJECTIVE: To examine temporal trends in the rates of severe bronchopulmonary dysplasia (BPD) between 1994 and 2002. STUDY DESIGN: In a retrospective cohort study, all infants with a gestational age (GA) <33 weeks in a large managed care organization were identified. Annual rates of BPD (defined as an oxygen requirement at 36 weeks corrected GA), severe BPD (defined as respiratory support at 36 weeks corrected GA), and death before 36 weeks corrected GA were examined. RESULTS: Of the 5115 infants in the study cohort, 603 (12%) had BPD, including 246 (4.9%) who had severe BPD. There were 481 (9.5%) deaths before 36 weeks corrected GA. Although the decline in BPD in this period was not significant, the rates of severe BPD declined from 9.7% in 1994 to 3.7% in 2002. Controlling for gestational age, the odds ratio (95% CI) for annual rate of decline in severe BPD was 0.890 (0.841-0.941). Controlling for gestational age, deaths before 36 weeks corrected GA also declined, with the odds ratio (CI) for the annual decline being 0.944 (0.896-0.996). CONCLUSIONS: In this study population, the odds of having of BPD remained constant after controlling for GA. However, the odds of having severe BPD declined on average 11% per year between 1994 and 2002.

Rehospitalization in the first year of life among infants with bronchopulmonary dysplasia.

OBJECTIVE: To describe rates and identify risk factors for rehospitalization during the first year of life among infants with bronchopulmonary dysplasia (BPD). STUDY DESIGN: This was a retrospective cohort study of infants born at a gestational age (GA) <33 weeks, between 1995 and 1999. BPD was defined as requirement of supplemental oxygen and/or mechanical ventilation at 36 weeks' corrected GA. The outcome was rehospitalization for any reason before first birthday. RESULTS: In the first year of life, 118 of 238 (49%) infants with BPD were rehospitalized, more than twice the rate of rehospitalization of the non-BPD population, which was 309 of 1359 (23%) (P=<.0001). No measured factor discriminated between those infants with BPD who were and were not rehospitalized, even when only rehospitalizations for respiratory diagnoses were considered. CONCLUSIONS: Among premature infants, BPD substantially increases the risk of rehospitalization during the first year of life. Neither demographic nor physiologic factors predicted rehospitalization among the infants with BPD. Other factors, such as air quality of home environment, passive smoking exposure, respiratory syncytial virus prophylaxis, breast-feeding status, and/or parenting and primary care management styles, should be examined in future studies.