Does low-normal serum TSH level adversely impact cognition in elderly adults and might methimazole therapy improve outcomes?

Serum thyroid stimulating hormone (TSH) levels increase with age. This elevation has been associated with better outcomes in very elderly subjects; however, little is known about the relationship between TSH below the lower limit of the reference range and health-related outcomes. Here, we investigated the association between cognitive impairment or depressive symptoms and low-normal serum TSH (<1.0 µIU/mL, in the reference range) in elderly subjects and whether the use of methimazole in subjects without dementia but with low-normal TSH could affect cognition or depressive symptoms. From 293 healthy adults ≥65 years old with normal TSH included in the sectional phase, only subjects without dementia were prospectively analyzed: 1) TSH ≥1.0 µIU/mL (observation; untreated); 2) TSH <1.0 µIU/mL (observation; untreated); and 3) TSH <1.0 µIU/mL (methimazole therapy). Cognition was assessed, using the Mini Mental State Examination (MMSE) and depressive symptoms (at MMSE ≥ 13) by the Geriatric Depression Scale (GDS). Age >80 years was the sole independent factor associated with dementia (OR=2.89; confidence interval [CI] 1.72-4.86; p<0.01). Prospectively, 93 completed follow-up, with 7.5% (7) receiving methimazole intervention. Untreated subjects with lower TSH showed the greatest declines in MMSE scores during follow-up that was not observed in those with serum TSH ≥1.0 µIU/mL. Lower MMSE score reductions were associated with elderly subjects receiving methimazole. There were no significant changes in depressive symptoms and GDS scores among those with serum TSH <1.0 µIU/mL. In this study, low-normal TSH was not associated with higher prevalence of dementia. However, in elderly subjects without dementia, low TSH was associated with worsening cognition.

[Carotid intima-media thickness as a marker of cardiovascular risk in patients with subclinical hypothyroidism]. / Espessura íntima-média carotídea como marcador de risco cardiovascular em pacientes com hipotireoidismo subclínico.

Subclinical hypothyroidism (SH) has been associated with an increased risk for coronary disease. Carotid intima-media thickness (IMT), as assessed by ultrasonography, is a precise marker of atherosclerotic changes and can be used as an endpoint for cardiovascular events. Aims of this study were to determine carotid IMT in a group of patients with SH and its possible association with an increase in cardiovascular risk. There were no significant differences in mean carotid IMT between patients and controls. Results of both groups were, respectively: common carotid arteries, 0.573 +/- 0.070 mm and 0.576 +/- 0.068 mm (p= 0.904); carotid bifurcation, 0.602 +/- 0.079 mm and 0.617 +/- 0.102 mm (p= 0.714). Similar results were obtained when analyzing subgroups with serum TSH < or > 8 mIU/L and with positive or negative titers of TPOAb. The mean carotid IMT in these subgroups were: TSH 4-8 mIU/L: 0.579 +/- 0.070 mm and 0.586 +/- 0.063 mm; TSH > 8 mIU/L: 0.569 +/- 0.073 mm and 0.616 +/- 0.091 mm; TPOAb+: 0.585 +/- 0.070 mm and 0.621 +/- 0.085 mm; TPOAb-: 0.554 +/- 0.072 mm and 0.571 +/- 0.066 mm. No differences in the lipid profile and in the apoprotein B and lipoprotein (a) levels between the groups were found. These findings suggest that mild SH with no related metabolic changes is not associated with an increase in cardiovascular risk, as assessed by carotid IMT.

Espessura íntima-média carotídea como marcador de risco cardiovascular em pacientes com hipotireoidismo subclínico / Carotid intima-media thickness as a marker of cardiovascular risk in patients with subclinical hypothyroidism

O hipotireoidismo subclínico (HS) já foi associado a aumento do risco cardiovascular. Na avaliação desse risco, a medida da espessura íntima-média (EIM) carotídea por ultra-sonografia é capaz de detectar alterações iniciais da aterosclerose. O objetivo deste estudo foi avaliar a EIM carotídea em pacientes com HS e sua associação com um provável aumento do risco cardiovascular. Não foi encontrada diferença significativa nas medidas da EIM das pacientes com HS e das controles. Os resultados encontrados nos dois grupos estudados foram, respectivamente: 0,573 ± 0,070 mm vs. 0,576 ± 0,068 mm para as carótidas comuns (p= 0,904) e 0,602 ± 0,079 mm vs. 0,617 ± 0,102 mm para as bifurcações (p= 0,714). Mesmo após estratificação das pacientes de acordo com o TSH e com a presença ou não de auto-imunidade, a diferença entre os sub-grupos permaneceu sem significância estatística. As medidas da EIM nesses grupos nos sítios avaliados foram: TSH 4-8 mUI/L: 0,579 ± 0,070 mm e 0,586 ± 0,063 mm; TSH > 8 mUI/L: 0,569 ± 0,073 mm e 0,616 ± 0,091 mm; anti-TPO+: 0,585 ± 0,070 mm e 0,621 ± 0,085 mm; anti-TPO-: 0,554 ± 0,072 mm e 0,571 ± 0,066 mm. Também não houve diferença no lipidograma e nas dosagens de apoproteína B e de lipoproteína (a). Este fato sugere que o HS, quando leve, sem alterações metabólicas associadas, não promove aumento do risco cardiovascular.

Subclinical hypothyroidism (SH) has been associated with an increased risk for coronary disease. Carotid intima-media thickness (IMT), as assessed by ultrasonography, is a precise marker of atherosclerotic changes and can be used as an endpoint for cardiovascular events. Aims of this study were to determine carotid IMT in a group of patients with SH and its possible association with an increase in cardiovascular risk. There were no significant differences in mean carotid IMT between patients and controls. Results of both groups were, respectively: common carotid arteries, 0.573 ± 0.070 mm and 0.576 ± 0.068 mm (p= 0.904); carotid bifurcation, 0.602 ± 0.079 mm and 0.617 ± 0.102 mm (p= 0.714). Similar results were obtained when analyzing subgroups with serum TSH < or > 8 mIU/L and with positive or negative titers of TPOAb. The mean carotid IMT in these subgroups were: TSH 4-8 mIU/L: 0.579 ± 0.070 mm and 0.586 ± 0.063 mm; TSH > 8 mIU/L: 0.569 ± 0.073 mm and 0.616 ± 0.091 mm; TPOAb+: 0.585 ± 0.070 mm and 0.621 ± 0.085 mm; TPOAb-: 0.554 ± 0.072 mm and 0.571 ± 0.066 mm. No differences in the lipid profile and in the apoprotein B and lipoprotein (a) levels between the groups were found. These findings suggest that mild SH with no related metabolic changes is not associated with an increase in cardiovascular risk, as assessed by carotid IMT.