The Health and Economic Well-Being of US Mothers with Intellectual Impairments.

The study compared groups at one time point, so it cannot show that intellectual impairment caused the health or economic differences. Most outcomes were reported by the mothers, so they may be affected by memory or by wanting to answer in a way that seems acceptable. Intellectual impairment was defined by a vocabulary test score below 80, not by clinical diagnosis or consideration of severity, so the group may differ from people with diagnosed intellectual disability. The sample excluded mothers who did not take the vocabulary test or did not speak English well enough, and it represents births in large US cities, so it may not apply to rural families or other groups. The comparisons were largely unadjusted, so other factors such as income, education, race or family circumstances may explain some differences. Some measures were well established for the general population but had not been validated for adults with intellectual impairments. Attrition is inherent in longitudinal surveys, although the age-three response rate was 86%.

Do not conclude that mothers with intellectual impairments have worse emotional health or more parenting stress. This study found no differences for emotional health, parenting stress or partner support. Do not treat the health and economic differences as proof that intellectual impairment caused them, because the study was observational and did not adjust for other factors.