Children’s math and reading skills are linked to better maternal health in midlife

An analysis of National Longitudinal Survey of Youth data found that mothers whose children were better at math and reading tended to be healthier. On the other hand, low levels of math and reading comprehension in children were related to larger declines in mothers’ physical health between 40 and 50 years of age. The paper was published in Intelligence.

Intelligence is the general capacity to learn, reason, solve problems, understand complex information, and adapt effectively to new situations. It has been linked to a wide range of health outcomes, with higher intelligence and cognitive ability generally associated with better physical health, better mental health, and a lower risk of death. These associations have helped give rise to cognitive epidemiology, a field that examines how cognitive abilities relate to health and disease across the lifespan.

The relationship between intelligence and health likely begins early, as childhood intelligence has been associated with health outcomes many decades later. At the same time, parental health can influence children’s cognitive development, with maternal depression, physical health problems, and other adverse conditions sometimes associated with poorer cognitive outcomes in children. Because influences can run in both directions, researchers increasingly view the family rather than the individual as an important unit for understanding the relationship between intelligence and health.

Study author Linda Wänström and her colleagues explored the relationship between family intelligence and maternal health. More specifically, they focused on the association between the intelligence of children and the health of their mothers.

These researchers used data from the National Longitudinal Survey of Youth 1979 (NLSY79). This is a longitudinal survey of 12,686 US adolescents and young adults from 8,770 households, initially aged 14 to 21 at the end of 1978. The NLSY Children (NLSYC) dataset includes all biological children of the NLSY79 mothers, totaling 11,504 individuals. NLSYC participants have been surveyed every two years since 1986 and their familial connections with the NLSY79 participants tracked. About 51% of the NLSYC participants were male.

The NLSYC participants completed the Peabody Individual Achievement Test (PIAT) in mathematics, reading recognition, and reading comprehension every two years from ages 5 to 15, between 1986 and 2014. Each eligible child underwent up to five assessments.

Study authors used scores on these tests as a measure of intelligence. In the NLSY79 group, health assessments of mothers were conducted as they reached ages 40 and 50, starting during the survey years of 1998 and 2008, respectively. These assessments included a self-report measure of physical and mental health, and a depression scale. For mothers, there was also an intelligence assessment done when they were between 15 and 23 years old using the Armed Forces Qualifying Test, an achievement test often used as a proxy for an intelligence test.

The results showed that, on average, mothers’ depression symptoms increased between 40 and 50 years of age, while their physical health scores decreased. As expected, children’s math and reading scores increased as they grew up.

Mothers whose children had stronger math and reading scores tended to have better physical and mental health. On the other hand, low levels of math and reading comprehension in children were associated with larger declines in mothers’ physical health between 40 and 50 years of age.

“The results indicated that family-level intelligence is positively related to maternal health at middle-age,” the study authors wrote. They discussed the notion of a “Flynn effect transfer” within families. The Flynn effect is the well-documented historical phenomenon where intelligence test scores increase from generation to generation. The authors suggested that families with higher cognitive levels and gains, possibly due to mothers starting families later and belonging to later cohorts, exhibit better maternal health outcomes in midlife, which could be studied in future research.

The study contributes to the scientific understanding of the links between health and cognitive abilities. However, it should be noted that although the study originally talks about intelligence, it did not use a dedicated test of cognitive abilities, but used achievement tests as proxy indicators of intelligence. Such a decision is defensible as achievement test scores tend to be highly correlated with intelligence, but this view is not universally accepted among researchers.

The paper, “Family-level intelligence and maternal health: A cross-cohort, cross-generational longitudinal study using the NLSY,” was authored by Linda Wänström, Patrick O’Keefe, Graciela Muniz-Terrera, Stacey Voll, Frank D. Mann, Sean Clouston, Scott Hofer, and Joseph L. Rodgers.