Maternal education and newborn thyroid-stimulating hormone level in a congenital hypothyroidism screening program.

Objective

To examine the relationship between neonatal thyroid function and the formal education of mothers.Study design: Participants came from a population-based congenital hypothyroidism (CH) screening program in Tianjin, China.

Methods

Of 66,390 registered births in 2015, 60,568 mothers and newborns had complete data. Mothers were categorized into one of four categories based on their educational attainment: (a) midschool or less; (b) high school or equivalent; (c) university; or (d) post graduate. Newborn thyroid-stimulating hormone (TSH) level was measured on day 3-7. Two neonatal groups were created using cutoffs of TSH > 10 μIU/ml and TSH > 20 μIU/ml. Odds ratios (OR) for CH risk by maternal education were estimated from logistic regression models after adjusting for potential confounders.

Results

For TSH > 10 μIU/ml, the screen positive incidence rate for CH was 1:201 or 4.98 per 1000 births; for TSH > 20 μIU/ml, the incidence rate was 1:2222 or 0.45 per 1000 births. Screen positive incidence rates decreased with increasing maternal education level. Compared to mothers with a postgraduate education, the ORs (95% CI) for midschool or less, high school or equivalent, and university were 2.09 (1.08, 4.04), 1.45 (0.73, 2.90), and 1.61 (0.85, 3.06) using a cutoff of TSH > 10 μIU/ml. At the higher cutoff of TSH > 20 μIU/ml ORs (95% CI) for midschool or less and high school or equivalent were 3.05 (1.20,7.74) and 3.34 (1.24, 8.97), when compared to a composite reference category of university and postgraduate level education.

Conclusion

Maternal education is inversely related to neonatal thyroid function though the mechanism remains unexplained.