TSH concentrations in parents and their offspring: a cross-sectional family-based analysis.

OBJECTIVE Studies that evaluated the genetic influences on thyroid stimulating hormone (TSH) concentrations were primarily performed in twin cohorts. The aim of the present study was to investigate the sex-specific association of serum TSH concentrations between parents and their offspring. METHODS We used data from the population-based Heinz Nixdorf Recall Study and the associated MultiGeneration Study, including offspring and their biological parents. In 3,115 participants (including 1,558 offspring from 1,138 families), self-reported thyroid diseases and median TSH concentrations depending on thyroid status, were assessed. Familial associations of TSH concentrations was investigated in 1,485 healthy subjects using linear regression modelling in each group of the parent-offspring relationship using the parent's TSH concentration as the exposure of interest. To account for the family effect, a mixed-effects ordinal logistic regression model with random intercept varying at the family level was fitted, using the TSH concentration of the offspring classified into sex- and age-specific quartiles as the outcome. RESULTS For every one mIU/l increase in the mother's or father's TSH concentration, the daughter's TSH concentration increases by 0.13 mIU/l (95% confidence interval: -0.01; 0.27) and 0.19 mIU/l (0.05; 0.33) respectively, and the son's TSH concentration increases by 0.13 mIU/l (0.02; 0.25) and 0.20 mIU/l (0.08; 0.32) respectively. Further sensitivity analyses by expanding inclusion criteria and taking family clustering into account corroborated these results. CONCLUSIONS Serum TSH concentrations of parents are positively associated with those of their offspring in all sex-specific relationships.