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Open Access 01-12-2021 | Affective Disorder | Research article

Contribution of IQ in young adulthood to the associations of education and occupation with cognitive ability in older age

Authors: Insa Feinkohl, Petra Kozma, Friedrich Borchers, Simone J. T. van Montfort, Jochen Kruppa, Georg Winterer, Claudia Spies, Tobias Pischon

Published in: BMC Geriatrics | Issue 1/2021

Abstract

Background

Studies suggest that a higher education and occupation are each associated with a higher late-life cognitive ability, but their inter-relationships in their association with cognitive ability and the contribution of peak IQ in young adulthood (‘pre-morbid IQ’) often remain unclear.

Methods

Cross-sectional analysis of 623 participants aged ≥65 years of the BioCog study. Education was coded according to the International Standard Classification of Education (ISCED; range 1 to 6). Occupation was coded as ‘semi/unskilled’, ‘skilled manual’, ‘skilled non-manual’, ‘managerial’, ‘professional’. A summary score of global ability (‘g’) was constructed from six cognitive tests. Pre-morbid IQ was estimated from vocabulary. The Geriatric Depression Scale assessed symptoms of depression. Age- and sex-adjusted analyses of covariance were performed.

Results

Education (partial eta² 0.076; p < 0.001) and occupation (partial eta² = 0.037; p < 0.001) were each significantly associated with g. For education, the association was attenuated but remained statistically significant when pre-morbid IQ was controlled for (partial eta² 0.036; p < 0.001) and was unchanged with additional adjustment for depression (partial eta² 0.037; p < 0.001). For occupation, the association with g was no longer significant when pre-morbid IQ (partial eta² = 0.015; p = 0.06) and depression (partial eta² = 0.011; p = 0.18) were entered as covariates in separate steps. When education and occupation were entered concurrently into the fully adjusted model, only education was independently associated with g (partial eta² 0.030; p < 0.001; occupation, p = 0.93).

Conclusion

While a higher education and a higher occupation were each associated with a higher late-life cognitive ability, only for education some unique contribution to cognitive ability remained over and above its relationship with pre-morbid IQ, depression, and occupation. Further research is needed to address whether a longer time spent in education may promote late-life cognitive ability.

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Katzman R, Terry R, DeTeresa R, Brown T, Davies P, Fuld P, et al. Clinical, pathological, and neurochemical changes in dementia: a subgroup with preserved mental status and numerous neocortical plaques. Ann Neurol. 1988;23(2):138–44. https://doi.org/10.1002/ana.410230206.CrossRefPubMed

Deary IJ, Whalley LJ, Crawford JR. An 'instantaneous' estimate of a lifetime's cognitive change. Intelligence. 2004;32(2):113–9. https://doi.org/10.1016/j.intell.2003.06.001.CrossRef

Franzen MD, Burgess EJ, Smith-Seemiller L. Methods of estimating premorbid functioning. Arch Clin Neuropsychol. 1997;12(8):711–38. https://doi.org/10.1093/arclin/12.8.711.CrossRefPubMed

Dykiert D, der G, Starr JM, Deary IJ. Why is mini-mental state examination performance correlated with estimated premorbid cognitive ability? Psychol Med. 2016;46(12):2647–54. https://doi.org/10.1017/S0033291716001045.CrossRefPubMedPubMedCentral

McGurn B, Starr JM, Topfer JA, Pattie A, Whiteman MC, Lemmon HA, et al. Pronunciation of irregular words is preserved in dementia, validating premorbid IQ estimation. Neurology. 2004;62(7):1184–6. https://doi.org/10.1212/01.WNL.0000103169.80910.8B.CrossRefPubMed

Stern Y, Arenaza-Urquijo EM, Bartrés-Faz D, Belleville S, Cantilon M, Chetelat G, et al. Whitepaper: defining and investigating cognitive reserve, brain reserve, and brain maintenance. Alzheimers Dement. 2020;16(9):1305–11. https://doi.org/10.1016/j.jalz.2018.07.219.CrossRefPubMed

Staff, R.T. Reserve, brain changes, and decline. Neuroimaging Clin N Am. 2012;22(1):99–105. https://doi.org/10.1016/j.nic.2011.11.006.CrossRef

Von Stumm S, et al. Intelligence, social class of original, childhood behavior disturbance and education as predictors of status attainment in midlife in men: the Aberdeen children of the 1950s study. Intelligence. 2010;38(1):202–11. https://doi.org/10.1016/j.intell.2009.11.004.CrossRef

Deary IJ, Brett CE. Predicting and retrodicting intelligence between childhood and old age in the 6-day sample of the Scottish mental survey 1947. Intelligence. 2015;50:1–9. https://doi.org/10.1016/j.intell.2015.02.002.CrossRefPubMedPubMedCentral

10.

Kalzendorf J, Brueggen K, Teipel S. Cognitive reserve is not associated with hippocampal microstructure in older adults without dementia. Front Aging Neurosci. 2019;11:380.CrossRefPubMed

11.

Harrison SL, Sajjad A, Bramer WM, Ikram MA, Tiemeier H, Stephan BCM. Exploring strategies to operationalize cognitive reserve: a systematic review of reviews. J Clin Exp Neuropsychol. 2015;37(3):253–64. https://doi.org/10.1080/13803395.2014.1002759.CrossRefPubMed

12.

Caamaño-Isorna F, Corral M, Montes-Martínez A, Takkouche B. Education and dementia: a meta-analytic study. Neuroepidemiology. 2006;26(4):226–32. https://doi.org/10.1159/000093378.CrossRefPubMed

13.

Meng X, D'Arcy C. Education and dementia in the context of the cognitive reserve hypothesis: a systematic review with meta-analyses and qualitative analyses. PLoS One. 2012;7(6):e38268. https://doi.org/10.1371/journal.pone.0038268.CrossRefPubMedPubMedCentral

14.

Chapko D, et al. Life-course determinants of cognitive reserve (CR) in cognitive aging and dementia - a systematic literature review. Aging Ment Health. 2017:1–12.

15.

Valenzuela MJ, Sachdev P. Brain reserve and dementia: a systematic review. Psychol Med. 2006;36(4):441–54. https://doi.org/10.1017/S0033291705006264.CrossRefPubMed

16.

Opdebeeck C, Martyr A, Clare L. Cognitive reserve and cognitive function in healthy older people: a meta-analysis. Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2016;23(1):40–60. https://doi.org/10.1080/13825585.2015.1041450.CrossRefPubMed

17.

Mantri S, Nwadiogbu C, Fitts W, Dahodwala N. Quality of education impacts late-life cognition. Int J Geriatr Psychiatry. 2019;34(6):855–62. https://doi.org/10.1002/gps.5075.CrossRefPubMed

18.

Rusmaully J, Dugravot A, Moatti JP, Marmot MG, Elbaz A, Kivimaki M, et al. Contribution of cognitive performance and cognitive decline to associations between socioeconomic factors and dementia: a cohort study. PLoS Med. 2017;14(6):e1002334. https://doi.org/10.1371/journal.pmed.1002334.CrossRefPubMedPubMedCentral

19.

Armstrong MJ, Naglie G, Duff-Canning S, Meaney C, Gill D, Eslinger PJ, et al. Roles of education and IQ in cognitive Reserve in Parkinson's disease-mild cognitive impairment. Dement Geriatr Cogn Dis Extra. 2012;2(1):343–52. https://doi.org/10.1159/000341782.CrossRefPubMedPubMedCentral

20.

Pavlik VN, Doody RS, Massman PJ, Chan W. Influence of premorbid IQ and education on progression of Alzheimer's disease. Dement Geriatr Cogn Disord. 2006;22(4):367–77. https://doi.org/10.1159/000095640.CrossRefPubMed

21.

Kremen WS, Beck A, Elman JA, Gustavson DE, Reynolds CA, Tu XM, et al. Influence of young adult cognitive ability and additional education on later-life cognition. Proc Natl Acad Sci U S A. 2019;116(6):2021–6. https://doi.org/10.1073/pnas.1811537116.CrossRefPubMedPubMedCentral

22.

Winterer G, Androsova G, Bender O, Boraschi D, Borchers F, Dschietzig TB, et al. Personalized risk prediction of postoperative cognitive impairment - rationale for the EU-funded BioCog project. Eur Psychiatry. 2018;50:34–9. https://doi.org/10.1016/j.eurpsy.2017.10.004.CrossRefPubMed

23.

Folstein MF, Folstein SE, McHugh PR. 'Mini-mental state'. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12(3):189–98. https://doi.org/10.1016/0022-3956(75)90026-6.CrossRefPubMed

24.

UNESCO Institute for Statistics. International Standard of Classification ISCED 2011. Montreal: UNESCO Institute for statistics; 2012.CrossRef

25.

UNESCO Institute for Statistics. International Standard Classification of Education ISCED 1997. Montreal: UNESCO Institute for statistics; 1997.

26.

Gale CR, Booth T, Starr JM, Deary IJ. Intelligence and socioeconomic position in childhood in relation to frailty and cumulative allostatic load in later life: the Lothian birth cohort 1936. J Epidemiol Community Health. 2016;70(6):576–82. https://doi.org/10.1136/jech-2015-205789.CrossRefPubMed

27.

Raven J, Raven JC, Court JH. Manual for Raven's Progressive Matrices and Vocabulary Scales. Oxford: Oxford Psychologists Press Ltd.; 1998.

28.

Lehrl, S., Mehrfach-Wortschatz-Intelligenztest. 2005, Hogrefe.

29.

Schmand B, Bakker D, Saan R, Louman J. The Dutch Reading test for adults: a measure of premorbid intelligence level. Tijdschr Gerontol Geriatr. 1991;22(1):15–9.PubMed

30.

Raven J. The Raven's progressive matrices: change and stability over culture and time. Cogn Psychol. 2000;41(1):1–48. https://doi.org/10.1006/cogp.1999.0735.CrossRefPubMed

31.

Fischer X, et al. MWT-A-test-Mappe. Balingen: Spitta GmbH; 2001.

32.

Feinkohl I, Borchers F, Burkhardt S, Krampe H, Kraft A, Speidel S, et al. Stability of neuropsychological test performance in older adults serving as normative controls for a study on postoperative cognitive dysfunction. BMC Res Notes. 2020;13(1):55. https://doi.org/10.1186/s13104-020-4919-3.CrossRefPubMedPubMedCentral

33.

Deary IJ, Penke L, Johnson W. The neuroscience of human intelligence differences. Nat Rev Neurosci. 2010;11(3):201–11. https://doi.org/10.1038/nrn2793.CrossRefPubMed

34.

Spearman C. 'General intelligence', objectively determined and measured. Am J Psychol. 1904;15(2):201–92. https://doi.org/10.2307/1412107.CrossRef

35.

Penke L, Deary IJ. Some guidelines for structural equation mdoelling in cognitive neuroscience: the case of Charlton et al.'s study on white matter integrity and cognitive ageing. Neurobiol Aging. 2010;31(9):1656–60. https://doi.org/10.1016/j.neurobiolaging.2009.10.019.CrossRefPubMed

36.

Feinkohl I, Janke J, Hadzidiakos D, Slooter A, Winterer G, Spies C, et al. Associations of the metabolic syndrome and its components with cognitive impairment in older adults. BMC Geriatr. 2019;19(1):77. https://doi.org/10.1186/S12877-019-1073-7.CrossRefPubMedPubMedCentral

37.

Le Carret N, et al. The effect of education on cognitive performances and its implication for the constitution of the cognitive reserve. Dev Neuropsychol. 2003;23(3):317–37. https://doi.org/10.1207/S15326942DN2303_1.CrossRefPubMed

38.

Mielke MM, Vemuri P, Rocca WA. Clinical epidemiology of Alzheimer's disease: assessing sex and gender differences. Clin Epidemiol. 2014;6:37–48. https://doi.org/10.2147/CLEP.S37929.CrossRefPubMedPubMedCentral

39.

Halpern DF, LaMay ML. The smarter sex: a critical review of sex differences in intelligence. Educ Psychol Rev. 2000;12(2):229–46. https://doi.org/10.1023/A:1009027516424.CrossRef

40.

Deary IJ, et al. Intelligence and educational achievement. Intelligence. 2010;35(1):13–21.CrossRef

41.

Sanchez-Chaparro MA, Calvo-Bonacho E, Gonzalez-Quintela A, Fernandez-Labandera C, Cabrera M, Sainz JC, et al. Occupation-related differences in the prevalence of metabolic syndrome. Diabetes Care. 2008;31(9):1884–5. https://doi.org/10.2337/dc08-0431.CrossRefPubMedPubMedCentral

42.

Gabriel PE, Schmitz S. Gender differences in occupational distributions among workers. Monthly Labor Rev. 2007:19–24.

43.

Harvey PD, Reichenberg A, Bowie CR. Cognition and aging in psychopathology: focus on schizophrenia and depression. Annu Rev Clin Psychol. 2006;2(1):389–409. https://doi.org/10.1146/annurev.clinpsy.2.022305.095206.CrossRefPubMed

44.

Everson SA, Maty SC, Lynch JW, Kaplan GA. Epidemiologic evidence for the relation between socioeconomic status and depression, obesity, and diabetes. J Psychosom Res. 2002;53(4):891–5. https://doi.org/10.1016/S0022-3999(02)00303-3.CrossRefPubMed

45.

Kivimaki M, et al. Association between socioeconomic status and the development of mental and physical health conditions in adulthood: a multi-cohort study. Lancet Public Health. 2020;5(3):e140–9. https://doi.org/10.1016/S2468-2667(19)30248-8.CrossRefPubMed

46.

Fritz CO, Morris PE, Richler JJ. Effect size estimates: current use, calculations, and interpretation. J Exp Psychol Gen. 2012;141(1):2–18. https://doi.org/10.1037/a0024338.CrossRefPubMed

47.

Sheikh JI, Yesavage JA. Geriatric depression scale (GDS): recent evidence and development of a shorter version. Clin Gerontol. 1986;5(1–2):165–73.

48.

Smart EL, Gow AJ, Deary IJ. Occupational complexity and lifetime cognitive abilities. Neurology. 2014;83(24):2285–91. https://doi.org/10.1212/WNL.0000000000001075.CrossRefPubMedPubMedCentral

49.

Ritchie SJ, Bates TC, der G, Starr JM, Deary IJ. Education is associated with higher later life IQ scores, but not with faster cognitive processing speed. Psychol Aging. 2013;28(2):515–21. https://doi.org/10.1037/a0030820.CrossRefPubMed

50.

Ritchie SJ, Tucker-Drob EM. How much does education improve intelligence? A meta-analysis. Psychol Sci. 2018;29(8):1358–69. https://doi.org/10.1177/0956797618774253.CrossRefPubMedPubMedCentral

51.

Deary IJ, Johnson W. Intelligence and education: causal perceptions drive analytic processes and therefore conclusions. Int J Epidemiol. 2010;39(5):1362–9. https://doi.org/10.1093/ije/dyq072.CrossRefPubMed

52.

Richards M, Deary IJ. A life course approach to cognitive reserve: a model for cognitive aging and development? Ann Neurol. 2005;58(4):617–22. https://doi.org/10.1002/ana.20637.CrossRefPubMed

53.

Anderson EL, Howe LD, Wade KH, Ben-Shlomo Y, Hill WD, Deary IJ, et al. Education, intelligence and Alzheimer's disease: evidence from a multivariable two-sample Mendelian randomization study. Int J Epidemiol. 2020;49(4):1163–72. https://doi.org/10.1093/ije/dyz280.CrossRefPubMedPubMedCentral

54.

Brinch CN, Galloway TA. Schooling in adolescence raises IQ scores. Proc Natl Acad Sci U S A. 2012;109(2):425–30. https://doi.org/10.1073/pnas.1106077109.CrossRefPubMed

55.

Ritchie SJ, Bates TC, Deary IJ. Is education associated with improvements in general cognitive ability, or in specific skills? Dev Psychol. 2015;51(5):573–82. https://doi.org/10.1037/a0038981.CrossRefPubMedPubMedCentral

56.

Lavrencic LM, Churches OF, Keage HAD. Cognitive reserve is not associated with improved performance in all cognitive domains. Appl Neuropsychol Adult. 2018;25(5):473–85. https://doi.org/10.1080/23279095.2017.1329146.CrossRefPubMed

57.

Lavrencic LM, Richardson C, Harrison SL, Muniz-Terrera G, Keage HAD, Brittain K, et al. Is there a link between cognitive reserve and cognitive function in the oldest-old? J Gerontol Series A Biol Sci Med Sci. 2018;73(4):499–505. https://doi.org/10.1093/gerona/glx140.CrossRef

58.

Seblova D, Berggren R, Lövdén M. Education and age-related decline in cognitive performance: systematic review and meta-analysis of longitudinal cohort studies. Ageing Res Rev. 2020;58:101005. https://doi.org/10.1016/j.arr.2019.101005.CrossRefPubMed

59.

Feinkohl I, et al. Cognitive reserve and the risk of postoperative cognitive dysfunction. Dtsch Arztebl Int. 2017;114(7):110–7.PubMedPubMedCentral

60.

Starr JM, Whalley LJ, Inch S, Shering PA. The quantification of the relative effects of age and NART-predicted IQ on cognitive function in healthy old people. Int J Geriatr Psychiatr. 1992;7(3):153–7. https://doi.org/10.1002/gps.930070303.CrossRef

61.

Hiscock M. The Flynn effect and its relevance to neuropsychology. J Clin Exp Neuropsychol. 2007;29(5):514–29. https://doi.org/10.1080/13803390600813841.CrossRefPubMed

62.

Owen SV, Froman RD. Uses and abuses of the analysis of covariance. Res Nurs Health. 1998;21(6):557–62. https://doi.org/10.1002/(SICI)1098-240X(199812)21:6<557::AID-NUR9>3.0.CO;2-Z.CrossRefPubMed

Title: Contribution of IQ in young adulthood to the associations of education and occupation with cognitive ability in older age
Authors: Insa Feinkohl
Petra Kozma
Friedrich Borchers
Simone J. T. van Montfort
Jochen Kruppa
Georg Winterer
Claudia Spies
Tobias Pischon
Publication date: 01-12-2021
Publisher: BioMed Central
Keywords: Affective Disorder
Affective Disorder
Published in: BMC Geriatrics / Issue 1/2021
Electronic ISSN: 1471-2318
DOI: https://doi.org/10.1186/s12877-021-02290-y

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Contribution of IQ in young adulthood to the associations of education and occupation with cognitive ability in older age

Abstract

Background

Methods

Results

Conclusion

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Abstract

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Conclusion

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