We found that maternal literacy level was associated with a wide range of parenting behaviors important for child development, including provision of toys and learning materials, shared reading activities, teaching activities, and verbal responsivity in the home. As hypothesized, whereas educational level was associated with the cognitive home environment, these associations were attenuated and became nonsignificant after adjusting for literacy level. These findings suggest that literacy level may account for the well-established effect of educational level on parenting, which has important implications for research and clinical practice.
Researchers have historically focused on maternal educational level as one of the most important risk factors related to the cognitive home environment and child developmental outcomes. However, whereas educational level has been recognized as a marker for literacy level, it has also been recognized that education and literacy are not equivalent.45
Educational level, which is measured as years completed or degrees obtained, does not necessarily measure literacy level, which is a more specific measure of functional skills that are relevant to the “demands of everyday life.”33(p865)
As seen in our sample, as well as others, literacy level is often seen to vary in individuals with the same educational attainment.33,46
In finding that literacy level attenuates the impact of educational level, our results strongly suggest that researchers should measure literacy level in studies of the cognitive home environment and child development in at-risk, low-income populations.
Clinically, there has been a recent focus regarding literacy and health literacy as important factors related to health disparities among at-risk pediatric and adult populations.21,47-49
Using the National Adult Literacy Survey database, Sentell and Halpin33
found literacy to be a more powerful predictor of adult health status than education or race and suggested that interventions to improve literacy might be effective in reducing health disparities. Studies of parental health literacy have shown associations with child outcomes including infant mortality,24
management of chronic diseases such as asthma and diabetes,25,50
and health care access and utilization.21,51,52
The recent focus on literacy as an explanation for health disparities has led to the development of new preventive strategies. The American Academy of Pediatrics has sought to improve the effectiveness of anticipatory guidance by creating plain-language handouts more appropriate for all parents, including those with low literacy levels.53
Other studies have created pictograms to better explain medication regimens and have been successful in improving adherence.54,55
Pediatric programs to improve child emergent literacy, such as Reach Out and Read, have sought to work with mothers at varying literacy levels.56,57
Our results provide strong support for developing strategies that take low maternal literacy levels into account in providing health and developmental guidance, and for explicitly addressing some of the ways that low literacy levels may affect access to information or the cognitive home environment. It is also important to consider ways that low literacy level may limit a parent's ability to provide stimulation and to consider interventions, which directly identify and address the issue of maternal literacy as a risk factor.
There are a number of limitations to our results. The measure that we used to test mothers’ literacy was a measure of word reading, not comprehension. Future studies should include specific measures of additional literacy skills, such as those used in the National Assessment of Adult Literacy, which measured prose, document, and quantitative literacy.10
In addition, the overall variance in StimQ accounted for by maternal literacy was relatively small in magnitude. Further study of the relationship between literacy and developmental outcomes is needed to delineate the clinical significance of these findings; this work is presently in progress. Also, measurement of the cognitive home environment, the primary outcome variable, was collected via parent report; results therefore may have been affected by social desirability bias. In addition, whereas we hypothesized that both reading level and educational level would affect the cognitive home environment, it is possible that these are only markers of other parental attributes that were not directly measured in this study. Finally, most mothers were Spanish-speaking, and approximately half were born outside of the United States; many completed school in their country of origin. Because completion of ninth grade may have different implications depending on the country, these results may not be generalizable to other populations.
In conclusion, literacy may be a more specific indicator of risk than educational level in low-income families. Studies of low-income populations should therefore include direct measures of literacy level. Given the relationship between low literacy level and parenting behaviors known to be related to child outcomes, pediatricians should consider developing strategies to identify mothers with low literacy levels in order to support the cognitive home environments for children of low-literacy parents.