Beyond High-Income Countries: Low Numeracy Is Associated with Older Adult Age around the World.

Background: Numeracy, or the ability to understand and use numbers, has been associated with obtaining better health and financial outcomes. Studies in high-income countries suggest that low numeracy is associated with older age-perhaps especially among individuals with lower education. Here, we examined whether findings generalize to the rest of the world.

Methods: Gallup surveyed >150,000 participants for the 2019 Lloyd's Register Foundation World Risk Poll, from 21 low-income, 34 lower-middle income, 42 upper-middle income, and 43 high-income countries. Low numeracy was operationalized as failing to correctly answer, "Is 10% bigger than 1 out of 10, smaller than 1 out of 10, or the same as 1 out of 10?"

Results: Regressions controlling for participants' education, income, and other characteristics found that, worldwide, low numeracy was associated with older age, lower education, and their interaction. Findings held in each country-income category, although low numeracy was more common in low-income countries than in high-income countries.

Limitations: Age differences may reflect cohort effects and life span-developmental changes.

Discussion: Low numeracy is more common among people who are older and less educated. We discuss the need for education and interventions outside of the classroom.

Highlights: We analyzed a global survey conducted in 21 low-income, 34 lower-middle income, 42 upper-middle income, and 43 high-income countries.Low numeracy was associated with older adult age, even after accounting for age differences in education.Low numeracy was more common in older people with lower education.