Influences of thyroid stimulating hormone on cognitive functioning in very old age.
ABSTRACT This study investigated the relationship of thyroxine (T4) and thyroid stimulating hormone (TSH) within normal ranges to cognitive performance in very old age. The participants (N = 200) were selected from a population-based study of nondemented persons aged 75 to 96 years (M = 83.9 years). Tasks assessing episodic memory, verbal fluency, visuospatial ability, short-term memory, and perceptual-motor speed were examined. Results indicated that T4 was unrelated to performance. However, TSH was positively related to episodic memory performance, and the effects were independent of the influence of age, level of education, and depressive mood symptoms. There was no reliable effect of TSH on verbal fluency, short-term memory, perceptual-motor speed, or visuospatial functioning. The influence of TSH on episodic memory was interpreted in terms of its potential effects on encoding and consolidation processes.
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ABSTRACT: Context:Overt thyroid disease is associated with profound adverse health outcomes; however, data are conflicting for studies of borderline/subclinical thyroid dysfunction. Many studies of subclinical thyroid disease have had low power and were prone to selection bias. In contrast, large datasets are available from community studies in healthy individuals. Studies of the effects of variation of thyroid function across the reference range on health outcomes in these populations may provide useful information regarding thresholds for treatment of abnormal thyroid function.Evidence Acquisition:MEDLINE and the Cochrane Database of Systematic Reviews and Controlled Trials Register were searched for articles studying the effect of variation in thyroid hormone parameters within the reference range on cardiovascular, bone, metabolic, pregnancy, neurological, and psychological outcomes.Evidence Synthesis:Higher TSH/lower thyroid hormone levels are associated with more cardiovascular risk factors and cardiovascular events and worse metabolic parameters and pregnancy outcomes, whereas lower TSH/higher thyroid hormone levels are associated with reduced bone mineral density and increased fracture risk. The evidence base was good for cardiovascular, metabolic, bone, and pregnancy outcomes; however, high-quality data remained lacking for neurological and psychological outcomes.Conclusions:Common variations in persons with thyroid function in the normal range are associated with adverse health outcomes. These data suggest, by extrapolation, that carefully monitored treatment of even modest elevations of TSH may have substantial health benefits. Appropriately powered large-scale clinical trials analyzing the risks vs benefits of treating subclinical thyroid disease are required to determine whether these benefits can be achieved with levothyroxine therapy.The Journal of Clinical Endocrinology and Metabolism 07/2013; · 6.31 Impact Factor
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ABSTRACT: Thyroid hormone production, metabolism, and action change with aging. The reference ranges for serum thyrotropin and thyroid hormones are derived mainly from younger populations. Thus, the prevalence of subclinical thyroid dysfunction is increased greatly in the elderly. However, it is unclear whether mild thyroid dysfunction in the elderly is associated with adverse outcomes. In this review, we discuss current evidence-based literature on thyroid function in the elderly and whether subclinical thyroid dysfunction in the elderly should be treated.Journal of thyroid research. 01/2013; 2013:481287.
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ABSTRACT: Attention disorders are common symptoms in patients with untreated hyperthyroidism. Nevertheless, it is unknown whether they represent a global attention deﬁcit or selective impairment of attention networks. Thirty-seven patients with hyperthyroidism were recruited and underwent the Attention Network Test (ANT), which provided measures of three independent attention networks (alerting, orienting and executive control), before being treated with methimazole. This study demonstrated that patients with untreated hyperthyroidism had significant deficits in the alerting and executive control networks. Interestingly, a significant positive association was also found between T4 level and the value of the executive network in patients with hyperthyroidism. These results suggest that the patients with hyperthyroidism may not just exist a specific impairment of attention networks, and there was some relationship between the level of T4, not T3 or TSH, and the value of the executive control network in patients with hyperthyroidism.Neuroscience letters. 05/2014;