Vol.:(0123456789) 1 3 J Endocrinol Invest DOI 10.1007/s40618-017-0654-6 ORIGINAL ARTICLE Prevalence of thyroid dysfunction and its impact on cognition in older mexican adults: (SADEM study) T. Juárez‑Cedillo 1,2  · L. Basurto‑Acevedo 3  · S. Vega‑García 3  · A. Sánchez‑Rodríguez Martha 4  · R. Retana‑Ugalde 4  · E. Juárez‑Cedillo 1  · C. Gonzalez‑Melendez Roberto 2  · J. Escobedo‑de‑la‑peña 1   Received: 28 September 2016 / Accepted: 7 March 2017 © Italian Society of Endocrinology (SIE) 2017 22.66–26.77). Of these, 15.4% older adults were classifed as subclinical hypothyroidism, 7.2% overt hypothyroidism, 0.5% subclinical hyperthyroidism, and 0.6% overt hyper- thyroidism. The association of thyroid dysfunction with cognitive impairment was most evident in overt hypothy- roidism OR = 1.261 (1.185–1.343). Conclusions The present study demonstrated a high prev- alence of thyroid dysfunction in Mexican elderly people living in the community. A relationship between cognitive impairment and the presence of hypothyroidism was also shown, and to a lesser degree in hyperthyroidism. Keywords Cognitive function · Thyroid function · Elderly · Mexico · SADEM Introduction Thyroid disease is a common endocrine disorder whose prevalence of overt and subclinical hypothyroidism has been consistently reported, with frequencies ranging from 0.5 to 5% for overt hypothyroidism and from 5 to 20% for subclinical hypothyroidism [1–3]. However, only a limited number of studies have described thyroid disease in elderly patients and its impact on cognition. The thyroid, like other endocrine glands of the human body, has wide-ranging efects on nervous system, and overt thyroid dysfunctions are associated with several forms of cognitive impairment, peripheral neuropathies, and depressive or anxiety disor- ders [4]. Also, they act on muscular function, cardiovas- cular system [5], erythropoiesis, and oxidative stress [6], among other organic functions, as well as mobility [7], which is an important marker of independence for activities of daily living (ADLs) in old age. Abstract Introduction Subclinical thyroid dysfunction is a possible risk factor for cognitive impairment in old age, but results are inconsistent. Aim of the present study was to evaluate the prevalence of thyroid dysfunction among older com- munity-dwelling adults and to see whether thyroid function impacts the cognitive status of the elderly. Methods We included 1750 participants from the Study on Aging and Dementia in Mexico (SADEM). All sub- jects were evaluated clinically via specifc interviews. TSH levels were analyzed by chemiluminescent immu- nometry assay. We classifed participants into fve thy- roid state groups: (1) normal TSH levels (0.40–4.0 IU/L) were considered euthyroid; (2) Overt hyperthyroidism: TSH <0.3 IU/l and FT4 >23 pmol/l; (3) Overt hypothy- roidism: TSH >4.8 IU/l, FT4 <13 pmol/l; (4) Subclinical hyperthyroidism: TSH <0.3 IU/l, FT4: 13–23 pmol/l; (5) Subclinical hypothyroidism: TSH >4.8 IU/l, FT4: 13–23 pmol/l. Results The overall estimated prevalence of thyroid dysfunction in Mexican population was 23.7% (95% CI, * T. Juárez-Cedillo teresa.juarez@imss.gob.mx 1 Unidad de Investigación en Epidemiología Clínica, Hospital General Regional No 1 Carlos McGregor Sánchez Navarro, Gabriel Mancera 222, Colonia Del Valle, Delegación, Benito Juárez, 03100 México, DF, Mexico 2 High Studies (FES) Zaragoza, National Autonomous University of Mexico, Mexico City, Mexico 3 Endocrine Research Unit, National Medical Center, Mexican Institute of Social Security, Mexico City, Mexico 4 Gerontology Research Unit. Faculty of High Studies (FES) Zaragoza, National Autonomous University of Mexico, Mexico City, Mexico