Getting to a Root Cause of Health Disparities

Societal intolerance for gross disparities, especially in health, among its members has been used as a marker of advancement in development. Infant and maternal mortality are classic indices of disparity among countries, and these rates are additionally used to rank countries from least to most highly developed. Disparities in health indicators arise from a number of different sources. Populations can have differential susceptibility to diseases, such as the high rate of angle closure glaucoma among Chinese populations. All too often though, health disparities are the result of cultural or socioeconomic inequalities that can lead to barriers in prevention, diagnosis, or treatment of disease.

In this issue of Ophthalmic Epidemiology, Lam and colleagues report on disparities in the prevalence of self-reported visual impairment among racial and ethnic groups in the United States, using data from the National Health Interview Survey.¹ There are differences with higher rates as expected between non-Hispanic whites and African Americans, and whites and Hispanics. Such findings have been reported before from population-based studies using visual acuity testing in Baltimore and Salisbury, Maryland, Nogales and Tucson, Arizona and Los Angeles, California. Of interest are the high rates of self-reported impairment from Native Americans where one in five Native Americans age 45 years and older responded “yes” to the question ““Do you have any trouble seeing, even when wearing glasses or contact lenses?”

Some skepticism is justified because the question has not been validated against tested visual acuity with current spectacles or contacts in these sub-populations, and the interpretation of the question by these sub-groups may lead to mis-classification. However, these findings are not very disparate from those reported by Lee et al in Oklahoma who found a rate of best corrected acuity worse than 20/20 of 23% among Native Americans in their sample.² In that study, an additional 20% had best corrected distance acuity between 20/25 and 20/40. Cataract was the leading cause of visual loss in that population, followed by age-related macular degeneration and diabetic retinopathy. The authors concluded, as did Lam and colleagues from their sample of Native Americans across the United States, that Native Americans suffer disproportionately from visual loss, and it seems from causes that are largely curable or preventable.

Lam et al found the most consistent factor related to higher rates of reported visual impairment was a lower level of educational attainment, significant even when adjusting for age, gender, insurance status, and marital status. The association of low educational attainment and increased rates of self-reported visual impairment is consistent across all the population groups. The authors state that the finding is not surprising given previous associations of poorer access to health services and less use of services with lower education. This makes intuitive sense for visual loss due to cataract for example, which is remedial with surgery if barriers do not exist and services are accessed.

In fact, low educational attainment is associated with increased morbidity and mortality from a number of causes, many attributable to increased blood pressure, obesity, and use of tobacco. While the health sector has focused on materials to improve low rates of health literacy for specific health problems, there is growing recognition that little gains will made without a more general focus on improving educational attainment, and especially for the most disadvantaged populations. The United States census estimates that 14.3% of whites have less than high school education, compared to 18.9% of blacks, 29.1% of Native Americans and 41.5% of Latinos age 25 and older. Without a sustained focus on this root cause of health disparities, our health statistics are liable to continue to tell these sad stories of inequalities reported by Lam and Lee et al.

The current administration in Washington has ambitious goals for improving education in the United States, with the philosophy that investment in education will have future pay offs in economic prosperity. No doubt the pay off has the potential to be even wider, in terms of health and improved life outcomes. Whether or not fundamental improvements in education can be implemented in these difficult economic times remains to be seen.

It may seem odd to discuss the state of educational attainment in an ophthalmology journal. However, the disparities we report in health in general, or eye health in particular, can no longer be separated from disparities in educational attainment that we know exist, and without change in the latter, the former will be nearly impossible to eliminate.

Notes

*now classified in the United States census and official documents as American Indian and Alaskan Native, referred here as Native American.