Apolipoprotein E e4 allele status and later-life depression in the Lothian Birth Cohort 1936

Abstract

Background Previous results have been mixed regarding the role of the apolipoprotein E e4 (APOE e4) allele in later-life depression: some studies note that carriers experience greater symptoms and increased risk while others find no such association. However, there are few prospective, population-based studies of the APOE e4-depression association and fewer that examine depressive symptom trajectory and depression risk longitudinally. We examined the association between APOE e4 allele status and longitudinal change in depressive symptoms and depression risk in later-life, over a 12-year follow-up period. Methods We used data from 690 participants of the Lothian Birth Cohort 1936 who took part in the Scottish Mental Survey 1947 (aged 11) and were followed-up in later-life over five waves from 2004 to 2019 (aged 70–82). We used APOE e4 allele status to predict longitudinal change in depressive symptom scores and risk of depression (defined by a symptom score threshold or use of depression-related medication). Models were adjusted for sex, childhood cognitive ability, childhood social class, education, adult social class, smoking status and functional limitations at baseline. Results Depressive symptom scores increased with age. Once adjusted for covariates, APOE e4 allele status did not significantly predict symptom score trajectories or depression risk. Greater functional limitations at baseline significantly predicted poorer symptom score trajectories and increased depression risk (defined by medications). APOE e4 allele status did not significantly moderate the contribution of sex, education or functional limitations. Conclusions There was no evidence that APOE e4 carriers experience an increased risk for later-life depression.

Intergenerational Social Mobility and Health in Later Life: Diagonal Reference Models Applied to the Lothian Birth Cohort 1936

“…Where intergenerational social mobility was not associated with later-life health independently of socioeconomic position, higher socioeconomic position was associated significantly with reduced mortality odds, though only before correcting for multiple comparisons. Consistent with previous linear regression (Iveson & Deary, 2017;Iveson et al, 2021) and DRM (Präg & Richards, 2019) studies, the relative weights indicated a stronger contribution of adulthood (own) social class than childhood (father's) social class. Socioeconomic gradients in other later-life health outcomes appear to be explained by demographic (e.g., sex, age) and early-life (e.g., childhood cognitive ability) covariates as highlighted in previous work using this cohort (Gale et al, 2016;Iveson & Deary, 2017;Iveson et al, 2021) and also in other cohorts (Luo & Waite, 2005).…”

“…A binary depression variable indicated likely depression at any wave (depressed vs. not depressed). As in previous work ( Iveson et al, 2021 ), depression was defined at each wave as either a Hospital Anxiety and Depression Scale—Depression subscale total score of 8 or more (sensitivity = 74%, specificity = 84%; Wu et al, 2021 ) or the presence of one or more keywords (related to depression and antidepressants) in a self-reported list of prescribed medication ( Iveson et al, 2021 ).…”

“…12 test of intelligence administered in-school as part of the Scottish Mental Survey 1947 ( The Scottish Council for Research in Education, 1949 ). In line with previous work ( Iveson et al, 2021 ), raw scores (ranging from 0 to 76) were age-adjusted to account for small differences in age at test and then were IQ scaled ( M = 100, SD = 15) to aid interpretability.…”

“…12 test of intelligence administered in-school as part of the Scottish Mental Survey 1947 (The Scottish Council for Research in Education, 1949). In line with previous work (Iveson et al, 2021), raw scores (ranging from 0 to 76) were age-adjusted to account for small differences in age at test and then were IQ scaled (M = 100, SD = 15) to aid interpretability. Mobility effects were estimated using DRMs (Sobel, 1981); these are nonlinear models that simultaneously estimate the effects of social class origin, destination, and mobility by using non-mobile individuals as a reference group for mobile individuals.…”

“…In the Lothian Birth Cohort 1936 (LBC1936), a single-year birth cohort of older adults (followed up between age 68 and 82), linear models have identified no significant association between social mobility and either later-life satisfaction or self-rated health ( Iveson & Deary, 2017 ) and no significant association between socioeconomic position (parental or own) and depression status ( Iveson et al, 2021 ). Meanwhile, studies have shown a significant association between higher socioeconomic position and lower later-life mortality risk in the LBC1936 ( Fawns-Ritchie et al, 2018 ).…”