Socioeconomic Status During Lifetime and Cognitive Impairment No-Dementia in Late Life: The Population-Based Aging in the Chianti Area (InCHIANTI) Study
Affiliations: [a] Department of Medical and Surgery Sciences, University of Brescia, Brescia, Italy | [b] Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm University, Stockholm, Sweden | [c] Stockholm Gerontology Research Center, Stockholm, Sweden | [d] A.S.F. Geriatric Rehabilitation, Florence, Italy | [e] Longitudinal Studies Section, National Institute on Aging, NIH, Baltimore, MD, USA
Correspondence:
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Correspondence to: Alessandra Marengoni, MD, PhD, Department of Medical and Surgery Sciences, University of Brescia Piazzale Spedali Civili 1, 25123 Brescia, Italy. Tel.: +39 030 2528479; Fax: +39 030 396011; E-mail: alessandra.marengoni@ki.se; marengon@med.unibs.it.
Abstract: Thousand and twelve dementia-free elderly (60–98 years old) enrolled in the InChianti Study (Italy) were evaluated at baseline (1998–2000) and at 3-year follow-up (2001–2003) with the aim of analyzing the association of lifetime socioeconomic status (SES) with prevalent and incident cognitive impairment no-dementia (CIND). SES was defined from information on formal education, longest held occupation, and financial conditions through life. CIND was defined as age-adjusted Mini-Mental State Examination score one standard deviation below the baseline mean score of participants without dementia. Logistic regression and Cox proportional-hazards models were used to estimate the association of SES with CIND. Demographics, occupation characteristics (i.e., job stress and physical demand), cardiovascular diseases, diabetes, apolipoprotein E (APOE) genotype, smoking, alcohol consumption, depressive symptoms, and C-reactive protein were considered potential confounders. Prevalence of CIND was 17.7%. In the fully adjusted model, low education (OR = 2.1; 95% confidence intervals, CI = 1.4 to 3.2) was associated with prevalent CIND. Incidence rate of CIND was 66.0 per 1000 person-years. Low education (HR = 1.7; 95% CI = 1.04 to 2.6) and manual occupation (HR = 1.9; 95% CI = 1.0 to 3.6) were associated with incident CIND. Among covariates, high job-related physical demand was associated with both prevalent and incident CIND (OR = 1.6; 95% CI = 1.1 to 2.4 and HR = 1.5; 95% CI = 1.0 to 2.3). After stratification for education, manual occupation was still associated with CIND among participants with high education (HR = 2.2; 95% CI = 1.2 to 4.3 versus HR = 1.4; 95% CI = 0.2 to 10.4 among those with low education). Proxy markers of lifetime SES (low education, manual occupation and high physical demand) are cross-sectional correlates of CIND and predict incident CIND over a three-year follow-up.
Keywords: Cognitive impairment no-dementia, epidemiology, education, finances, occupation, socioeconomic status
