The PAQUID survey and correlates of subclinical hypothyroidism in elderly community residents in the southwest of France.

Abstract

The aim of this study was to assess the prevalence of increased thyroid-stimulating hormone (TSH) levels (subclinical or undiagnosed hypothyroidism) in a representative sample of a community-living elderly population and to examine the relationships with cognitive functions and depressive symptoms. An epidemiological study was made of a cohort of 2792 subjects over 65 years of age. A blood sample was obtained from 425 volunteers of this cohort and assayed for TSH. Every subject participating in the study was interviewed and given a battery of neuropsychological tests by a psychologist. Three hundred and eighty-one subjects (89.7%) had normal TSH levels; 18 subjects (4.2%) had TSH lower than 0.4 microU/ml, associated in two of them with hyperthyroxinaemia. Twenty-six subjects (6.1%) had increased TSH levels, associated in 18 of them with a normal free thyroxine level and in eight with a low free thyroxine level. Increased TSH levels were significantly linked with female sex and with the presence of symptoms of depression on the CES-D scale but not with impairment of cognitive function.