Thyroid status and functional and cognitive status at baseline and survival after 3 years of follow-up: the OCTABAIX study

Abstract

Objective: Subclinical thyroid disorders are common in older individuals. Health risks associated with subclinical hypothyroidism in older adults are unclear. The aim of the study is to evaluate whether thyroid status in elderly subjects correlates with physical and cognitive function at baseline and with 3-year mortality. Design: A population-based, prospective cohort of the OCTABAIX study (307 inhabitants aged 85 years at baseline). Methods: Chronic drug prescription, functional status (Barthel and Lawton indices) and cognitive status according to the Spanish version of the Mini-Mental State Examination were recorded. Quality of life was assessed using the visual analogue scale of the quality of life test. Concentrations of TSH and thyroxine were measured. Participants were classified in accordance with clinical categories of thyroid function. Results: Twenty (6.5%) individuals had subclinical hypothyroidism and five (1.6%) had subclinical hyperthyroidism. Compared with euthyroid subjects (nZ280; 91.8%), subclinical hypo-and hyperthyroidism subjects were not significantly associated with poor physical or cognitive function at baseline. Fifty-one (15.1%) subjects died during the 36 months of follow-up. TSH values and subclinical hypo-and hyperthyroidism were not associated with an increased overall mortality risk (hazard ratio (HR) 1.086, 95% CI 0.987-1.196 and HR 0.905, 95% CI 0.902-1.053 respectively). Conclusions: This study does not support the association of TSH or thyroid disorders with physical or cognitive function at baseline or with 3-year mortality in the oldest old subjects.

Prevalence of Undiagnosed Hypothyroidism in Europe: A Systematic Review and Meta-Analysis

“…The sample size of selected studies varied between 307 [34] and 80,490 [35]. The studies included sample populations from Austria [35], Belgium [36], Bulgaria [37], Denmark [38], Germany [39, 40], Italy [16, 18, 41], Norway [15, 42], Spain [17, 19, 34, 43], The Netherlands [44, 45], the UK [46, 47], and Turkey [48]. …”

“…The report of selected articles results from cross-sectional analysis of 8 population-based surveys [15-18, 40-42, 49], 7 prospective cohort studies [34, 38, 39, 44-47], 2 retrospective cohort studies [35, 36], and 3 case-control studies [37, 43, 48]. …”

Higher FT4 or TSH below the normal range are associated with increased risk of dementia: a meta-analysis of 11 studies

“…After carefully scanning the titles and abstracts, 39 articles that were potentially eligible for inclusion were retrieved. After reading the full texts, 28 articles were excluded for the following reasons: nine studies were not cohort or case-control studies181920212223242526; 13 lacked usable data13141727282930313233343536; four had different study purposes37383940; one did not perform FT4 and TSH measurements41; and one was a replicate study with a shorter follow-up42 than that by de Jong et al 10 (Fig. 1).…”

Thyroid hormones are associated with longitudinal cognitive change in an urban adult population

“…(Ceballos, et al, 2009) Epidemiological studies indicated that thyroid dysfunction whether hypo- or hyper-thyroidism (overt or subclinical) increases the risk of cognitive impairment,(Beydoun, et al, 2013,Bono, et al, 2004,Correia, et al, 2009,Miller, et al, 2006,Munte, et al, 2001) although the evidence is still sparse. (Almeida, et al, 2007,Ceresini, et al, 2009,de Jongh, et al, 2011,Formiga, et al, 2014,Joffe, et al, 2013,Kramer, et al, 2009,Parle, et al, 2010,Samuels, et al, 2007,Wijsman, et al, 2013) It is less well-known how thyroid hormone fluctuations within normal ranges can affect cognitive outcomes in the general population, particularly when studies have examined cognitive performance among middle-aged adults. (Beydoun, et al, 2013,Beydoun, et al, 2012,Grigorova and Sherwin, 2012,van Boxtel, et al, 2004)…”