WASHINGTON, Dec. 16 (UPI) -- Low-income environments can increase the risk of childhood neurological impairment, which is separate from the cognitive and emotional delays often present with early-life poverty, according to a study by the National Institutes of Health.
Researchers note the impairment likely would not be seen by a casual observer, but increases risk for learning difficulties, attention deficit disorders and psychological conditions such as anxiety disorders and schizophrenia.
"The size of the effect we saw was modest," said Dr. Stephen Gilman, acting chief of the Health Behavior Branch at the National Institute of Child Health and Human Development, in a press release. "However, the findings do indicate that an impoverished environment may pose a hazard for a child's developing nervous system."
Researchers analyzed data on 36,443 participants collected between 1959 and 1974 as part of the United States Collaborative Perinatal Project on neurological abnormality before birth, at 4 months of age, and 1 and 7 years.
Researchers grouped parents as low, medium, or high likelihood of socioeconomic disadvantage based on education, employment, whether there were two parents in the home, and other factors. Accounting for risker pregnancies among women in poverty, testing at birth showed little difference between children of different socioeconomic groups. Starting at age 4 months, however, children born to the most socioeconomically disadvantaged parents had a 12.8 percent chance of having a neurological abnormality, compared with 9.3 percent of the least disadvantaged children.
By age 7, the chance of neurological abnormality was 20.2 percent among the most disadvantaged children and 13.5 percent among the least disadvantaged.
The researchers said the numbers may have shifted in the years since the original study, noting that new diagnostic approaches for neurological impairments, maternal alcohol or drug use, and increases in the number of children living below the federal poverty threshold being higher now could tilt the numbers.
"These findings reinforce the importance of the early environment for neurodevelopment generally, and expand knowledge regarding the domains of neurodevelopment affected by environmental conditions," researchers wrote in the study, published in the International Journal of Epidemiology. "Further work is needed to determine the mechanisms linking socioeconomic disadvantage with children's neural functioning, the timing of such mechanisms and their potential reversibility."