1. Insulin resistance: Genetic associations with depression and cognition in population based cohorts.
- Author
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Frangou, Sophia, Shirali, Masoud, Adams, Mark J., Howard, David M., Gibson, Jude, Hall, Lynsey S., Smith, Blair H., Padmanabhan, Sandosh, Murray, Alison D., Porteous, David J., Haley, Chris S., Deary, Ian J., Clarke, Toni-Kim, and McIntosh, Andrew M.
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INSULIN resistance , *VERBAL ability , *COGNITION , *FAMILY health , *COGNITIVE ability - Abstract
Insulin resistance, broadly defined as the reduced ability of insulin to exert its biological action, has been associated with depression and cognitive dysfunction in observational studies. However, it is unclear whether these associations are causal and whether they might be underpinned by other shared factors. To address this knowledge gap, we capitalized on the stability of genetic biomarkers through the lifetime, and on their unidirectional relationship with depression and cognition. Specifically, we determined the association between quantitative measures of cognitive function and depression and genetic instruments of insulin resistance traits in two large-scale population samples, the Generation Scotland: Scottish Family Health Study (GS: SFHS; N = 19,994) and in the UK Biobank (N = 331,374). In the GS:SFHS, the polygenic risk score (PRS) for fasting insulin was associated with verbal intelligence and depression while the PRS for the homeostasis model assessment of insulin resistance was associated with verbal intelligence. Despite this overlap in genetic architecture, Mendelian randomization analyses in the GS:SFHS and in the UK Biobank samples did not yield evidence for causal associations from insulin resistance traits to either depression or cognition. These findings may be due to weak genetic instruments, limited cognitive measures and insufficient power but they may also indicate the need to identify other biological mechanisms that may mediate the relationship from insulin resistance to depression and cognition. • Insulin resistance (INS-R) is broadly defined as the reduced ability of insulin to exert its biological action. • Measures of INS- R are associated with depression and cognitive dysfunction. • We used two large population samples to estimate genetic associations. • The polygenic risk of INS-R was associated with depression and cognition this association did not appear to be causal. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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