Lower parental numeracy is associated with children being under- and overweight

In adults, lower numeracy is associated with poorer nutrition label comprehension and higher BMI. It remains unclear whether parental numeracy also impacts children's body weight.

We examined the relationship between parental numeracy and children's BMI z-scores and analyzed whether weight-related numerical information processing skills-specifically, portion-size estimation skills, comprehension of nutrition labels, and comprehension of growth charts-mediated that relationship.

Numeracy, portion-size estimation skills, comprehension of nutrition labels, and comprehension of growth charts were assessed in face-to-face interviews with 320 parents of children aged 6-12 years in Germany. Parent and child body weight were measured; parents reported both their own height and that of their children.

Lower parental numeracy was significantly associated with having a child who was either underweight (β = 0.126, P = 0.048) or overweight (β = -0.299, P < 0.001). Lower parental numeracy was also associated with poorer portion-size estimation skills (r = -0.08, P = 0.023) and inferior comprehension of growth charts (r = 0.33, P < 0.001) and nutrition labels (r = 0.26, P < 0.001). However, these weight-related numerical information processing skills did not mediate the association between parental numeracy and children's BMI.

This study is the first to find lower parental numeracy to be a risk factor for children being either over- or underweight. However, portion-size estimation skills, comprehension of nutrition labels, and comprehension of growth charts did not mediate the association between parental numeracy and children's BMI. The present findings thus winnow down the set of mechanisms potentially underlying this association. Parental numeracy is an as yet largely overlooked factor that can be targeted when developing interventions to prevent and treat malnutrition and to achieve and maintain a healthy body weight in children.