Abstract / Summary
Abstract The role of stress-induced thyroid dysfunction in the development of hypertension remains unclear. We tested whether thyroid status modifies or mediates the relationship between psychological distress and blood pressure in sex-stratified two independent cohorts. The NHANES thyroid module (N = 8,310; 4,177 men, 4,133 women; United States, 2007-2012) provided depression (PHQ-9), T3, T4, and blood pressure. The LEMON study (N = 227; 145 men, 82 women; Germany) provided trait anxiety, perceived stress, Hamilton depression, TICS chronic-stress subscales, TSH, and blood pressure. We tested sex-stratified moderation and mediation hypotheses for the effect of thyroid variables on the association between psychological distress and blood pressure, followed by the subgroup analysis. The odds of diastolic hypertension comorbid with hypothyroidism in NHANES women with depression was OR=2.22 (95% CI: 1.46-3.36, p=0.0002). Depression was inversely associated with free T4 (β = -0.027, p = 0.017) and total T4 (β = -0.028, p = 0.029), each predicted diastolic BP (β = -0.081 and -0.062, both p<0.001), with a significant mediation effect (ACME = 0.00215 & 0.00174 respectively, p<0.05). In LEMON women, TSH positively moderated the effect of Hamilton depression and chronic worrying on diastolic BP (β interaction = 0.213 and 0.207, p<0.05); within the high-TSH subgroup, both independently predicted diastolic BP (β = 0.307 and 0.248, p<0.05). However, there were neither moderated nor mediated effects of thyroid variables in men. Analysis reveals a potential Female-specific role of thyroid function in linking depression to elevated diastolic blood pressure, indicating a thyroid-vascular axis in women.