{"id":17700,"date":"2025-12-21T15:23:58","date_gmt":"2025-12-21T20:23:58","guid":{"rendered":"https:\/\/ccna-ccnv.ca\/?post_type=ccna_publication&#038;p=17700"},"modified":"2026-02-02T15:24:36","modified_gmt":"2026-02-02T20:24:36","slug":"thyroid-function-and-cognitive-health-rethinking-the-relationship-between-suboptimal-tsh-ft4-levels-and-cognitive-decline","status":"publish","type":"ccna_publication","link":"https:\/\/ccna-ccnv.ca\/fr\/ccna_publication\/thyroid-function-and-cognitive-health-rethinking-the-relationship-between-suboptimal-tsh-ft4-levels-and-cognitive-decline\/","title":{"rendered":"Thyroid function and cognitive health: rethinking the relationship between \u00ab\u00a0suboptimal\u00a0\u00bb TSH\/FT4 levels and cognitive decline"},"content":{"rendered":"<h2>Abstract<\/h2>\n<p><strong class=\"sub-title\">Introduction:\u00a0<\/strong>Controversial hypotheses suggest that \u00ab\u00a0suboptimal\u00a0\u00bb thyroid function &#8211; defined as higher-normal thyroid-stimulating hormone (TSH) (2.0 to 4.5 \u03bcIU\/mL) or low-normal free thyroxine (FT4) &#8211; may increase risk of cognitive decline and dementia in older patients.<\/p>\n<p><strong class=\"sub-title\">Methods:\u00a0<\/strong>We examined this claim using data from the Canadian Comprehensive Assessment of Neurodegeneration and Dementia cohort (ages 50 to 91; cognitive statuses from unimpaired to dementia, rarer subtypes of dementia excluded). Thyroid function was categorized as \u00ab\u00a0optimal\u00a0\u00bb (TSH &lt; 2.0 \u03bcIU\/mL or FT4 \u2265 16.74 pmol\/L) or \u00ab\u00a0suboptimal.\u00a0\u00bb Six hundred eighty-eight participants had TSH data, and 476 participants had FT4 data.<\/p>\n<p><strong class=\"sub-title\">Results:\u00a0<\/strong>Chi-squared analyses showed no significant association between \u00ab\u00a0suboptimal\u00a0\u00bb thyroid function and cognitive impairment (TSH: \u03c7<sup>2<\/sup>\u00a0= 0.178, p = 0.67; FT4: \u03c7<sup>2<\/sup>\u00a0= 0.0027, p = 0.96). True hypothyroidism was rare; 98.6% of those with elevated TSH had normal FT4.<\/p>\n<p><strong class=\"sub-title\">Discussion:\u00a0<\/strong>These findings do not support claims that higher-normal TSH or low-normal FT4 contribute to cognitive impairment. Caution is warranted against advocating unproven thyroid supplementation for cognitive health.<\/p>\n","protected":false},"author":14,"featured_media":0,"template":"","meta":{"_acf_changed":false},"studies-relation":[228,51],"class_list":["post-17700","ccna_publication","type-ccna_publication","status-publish","hentry","studies-relation-compass-fr","studies-relation-compass-nd-fr"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v25.8 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Thyroid function and cognitive health: rethinking the relationship between &quot;suboptimal&quot; TSH\/FT4 levels and cognitive decline - CCNA - CCNV<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/ccna-ccnv.ca\/fr\/ccna_publication\/thyroid-function-and-cognitive-health-rethinking-the-relationship-between-suboptimal-tsh-ft4-levels-and-cognitive-decline\/\" \/>\n<meta property=\"og:locale\" content=\"fr_CA\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Thyroid function and cognitive health: rethinking the relationship between &quot;suboptimal&quot; 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