Sex/gender and socioeconomic differences in modifiable risk factors for dementia.

Both sex/gender and socioeconomic differences have been reported in the prevalence of modifiable risk factors for dementia. However, it remains unclear whether the associations between modifiable risk factors for dementia and incident dementia differ by sex/gender or socioeconomic status. This study aimed to investigate sex/gender and socioeconomic differences in the associations of modifiable risk factors with incident dementia using a life-course perspective. We used data from the English Longitudinal Study of Ageing (2008/2009 to 2018/2019). A total of 8,941 individuals were included [mean (standard deviation) age, 66.1 ± 9.8 years; 4,935 (55.2%) were women]. No overall sex/gender difference in dementia risk was found. Dementia risk was higher among those who experienced childhood deprivation [hazard ratio (HR) = 1.51 (1.17; 1.96)], lower occupational attainment [HR low versus high = 1.60 (1.23; 2.09) and HR medium versus high = 1.53 (1.15; 2.06)], and low wealth [HR low versus high = 1.63 (1.26; 2.12)]. Though different associations were found among the subgroups, there might be a sex/gender difference in dementia risk only for low cognitive activity, suggesting a higher risk for women [HR = 2.61 (1.89; 3.60)] compared to men [HR = 1.73 (1.20; 2.49)]. No consistent socioeconomic differences in modifiable dementia risk were found. A population-based approach that tackles inequalities in dementia risk profiles directly may be more effective than individual approaches in dementia prevention.

The association of white matter connectivity with prevalence, incidence and course of depressive symptoms: The Maastricht Study.

BACKGROUND: Altered white matter brain connectivity has been linked to depression. The aim of this study was to investigate the association of markers of white matter connectivity with prevalence, incidence and course of depressive symptoms. METHODS: Markers of white matter connectivity (node degree, clustering coefficient, local efficiency, characteristic path length, and global efficiency) were assessed at baseline by 3 T MRI in the population-based Maastricht Study (n = 4866; mean ± standard deviation age 59.6 ± 8.5 years, 49.0% women; 17 406 person-years of follow-up). Depressive symptoms (9-item Patient Health Questionnaire; PHQ-9) were assessed at baseline and annually over seven years of follow-up. Major depressive disorder (MDD) was assessed with the Mini-International Neuropsychiatric Interview at baseline only. We used negative binominal, logistic and Cox regression analyses, and adjusted for demographic, cardiovascular, and lifestyle risk factors. RESULTS: A lower global average node degree at baseline was associated with the prevalence and persistence of clinically relevant depressive symptoms [PHQ-9 ⩾ 10; OR (95% confidence interval) per standard deviation = 1.21 (1.05-1.39) and OR = 1.21 (1.02-1.44), respectively], after full adjustment. On the contrary, no associations were found of global average node degree with the MDD at baseline [OR 1.12 (0.94-1.32) nor incidence or remission of clinically relevant depressive symptoms [HR = 1.05 (0.95-1.17) and OR 1.08 (0.83-1.41), respectively]. Other connectivity measures of white matter organization were not associated with depression. CONCLUSIONS: Our findings suggest that fewer white matter connections may contribute to prevalent depressive symptoms and its persistence but not to incident depression. Future studies are needed to replicate our findings.

The cardiometabolic depression subtype and its association with clinical characteristics: The Maastricht Study.

BACKGROUND: Individuals with depression often show an adverse cardiometabolic risk profile and might represent a distinct depression subtype. The aim of this study was to investigate whether a cardiometabolic depression subtype could be identified and to investigate its association with demographics and clinical characteristics (severity, symptomatology, anti-depressant use, persistence and cognitive functioning). METHODS: We used data from The Maastricht Study, a population-based cohort in the southern part of The Netherlands. A total of 248 participants with major depressive disorder were included (mean [SD] age, 58.8 ± 8.5 years; 121 [48.8 %] were men). Major depressive disorder was assessed at baseline by the Mini-International Neuropsychiatric Interview. Cardiometabolic risk factors were defined as indicators of the metabolic syndrome according to the National Cholesterol Education Program Adult Treatment Panel III guidelines. We measured severity and persistence of depressive symptoms by use of the 9-item Patient Health Questionnaire. RESULTS: Latent class analysis resulted in two subtypes, one with cardiometabolic depression (n = 145) and another with non-cardiometabolic depression (n = 103). The cardiometabolic depression subtype was characterized by being male, low education, more severe depressive symptoms, less symptoms of depressed mood and more symptoms of loss of energy, more use of antidepressant medication and lower cognitive functioning. LIMITATIONS: No conclusions can be made about causality. CONCLUSIONS: Latent class analysis suggested a distinct cardiometabolic depression subtype. Participants with cardiometabolic depression differed from participants with non-cardiometabolic depression in terms of demographics and clinical characteristics. The existence of a cardiometabolic depression subtype may indicate the need for prevention and treatment targeting cardiometabolic risk management.

Association of Retinal Nerve Fiber Layer Thickness, an Index of Neurodegeneration, With Depressive Symptoms Over Time.

Importance: Whether neurodegeneration contributes to the early pathobiology of late-life depression remains incompletely understood. Objective: To investigate whether lower retinal nerve fiber layer (RNFL) thickness, a marker of neurodegeneration, is associated with the incidence of clinically relevant depressive symptoms and depressive symptoms over time. Design, Setting, and Participants: This is a population-based cohort study from the Netherlands (The Maastricht Study) with baseline examination between 2010 and 2020 and median (IQR) follow-up of 5.0 (3.0-6.0) years. Participants were recruited from the general population. Individuals with type 2 diabetes were oversampled by design. Data analysis was performed from September 2020 to January 2021. Exposures: RNFL, an index of neurodegeneration, assessed with optical coherence tomography. Main Outcomes and Measures: Depressive symptoms were assessed with the Patient Health Questionnaire (PHQ)-9 (continuous score, 0-27) at baseline and over time via annual assessments. The presence of clinically relevant depressive symptoms was defined as a PHQ-9 score of 10 or higher. Results: We used data from 4934 participants with depressive symptoms over time (mean [SD] age, 59.7 [8.4] years; 2159 women [50.8%]; 870 had type 2 diabetes [20.5%]). Lower RNFL thickness was associated with higher incidence of clinically relevant depressive symptoms (per 1 SD, hazard ratio 1.11; 95% CI, 1.01-1.23) and more depressive symptoms over time (per 1 SD, rate ratio, 1.04; 95% CI, 1.01-1.06), after adjustment for demographic, cardiovascular, and lifestyle factors. Conclusions and Relevance: The findings of this study suggest that lower RNFL thickness is associated with higher incidence of clinically relevant depressive symptoms and more depressive symptoms over time. Hence, neurodegeneration may be associated with the early pathobiology of late-life depression.

Low-grade inflammation and endothelial dysfunction predict four-year risk and course of depressive symptoms: The Maastricht study.

BACKGROUND: Low-grade inflammation (LGI) and endothelial dysfunction (ED) might play a key role in the development of depression. We investigated the associations and mediation of LGI and ED with four-year incidence and course of depressive symptoms (remitted, recurrent or persistent). DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS: In this prospective cohort study (mean age 59.6 ± 8.2 years, 48.9% women, 26.6% diabetes by design), Cox and multinomial regression analyses, adjusted for age, sex, educational level and diabetes status were used to investigate the associations of LGI and ED with onset and course of depressive symptoms as assessed by the PHQ-9 questionnaire. RESULTS: During 10,847 person-years of follow-up, 264 participants developed incident depression. Higher levels of LGI (OR [95%CI] per SD 1.32[1.16-1.49], p < 0.001) and ED (1.26[1.11-1.43], p < 0.001) were associated with incident depressive symptoms. In mediation analysis, 60% of the total effect of ED with incident depressive symptoms could be attributed to LGI. 76 out of 2637 participants had a persistent course of depressive symptoms. Higher levels of LGI (1.75[1.40-2.19], p < 0.001) and ED (1.33[1.04-1.71], p = 0.021) were associated with a persistent course of depressive symptoms. Higher ED was more strongly associated with persistent depressive symptoms (1.33[1.04-1.71], p = 0.021), while LGI was associated with remission of depression symptoms. CONCLUSIONS: LGI and ED were both associated with incident depressive symptoms, where the latter association was substantially mediated by LGI. ED was further associated with a persistent course of depressive symptoms, while LGI was not. These results suggest a temporal, vascular contribution of both LGI and ED to the etiology and chronicity of depressive symptoms.

The relation of depression with structural brain abnormalities and cognitive functioning: the Maastricht study.

BACKGROUND: Individuals with depression often experience widespread and persistent cognitive deficits, which might be due to brain atrophy and cerebral small vessel disease (CSVD). We therefore studied the associations between depression, markers of brain atrophy and CSVD, and cognitive functioning. METHODS: We used cross-sectional data from the population-based Maastricht study (n = 4734; mean age 59.1 ± 8.6 years, 50.2% women), which focuses on type 2 diabetes. A current episode of major depressive disorder (MDD, n = 151) was assessed by the Mini-International Neuropsychiatric Interview. Volumes of cerebral spinal fluid, white matter, gray matter and white matter hyperintensities, presence of lacunar infarcts and cerebral microbleeds, and total CSVD burden were assessed by 3 T magnetic resonance imaging. Multiple linear and logistic regression analyses tested the associations between MDD, brain markers and cognitive functioning in memory, information processing speed, and executive functioning & attention, and presence of cognitive impairment. Structural equation modeling was used to test mediation. RESULTS: In fully adjusted models, MDD was associated with lower scores in information processing speed [mean difference = -0.18(-0.28;-0.08)], executive functioning & attention [mean difference = -0.13(-0.25;-0.02)], and with higher odds of cognitive impairment [odds ratio (OR) = 1.60(1.06;2.40)]. MDD was associated with CSVD in participants without type 2 diabetes [OR = 1.65(1.06;2.56)], but CSVD or other markers of brain atrophy or CSVD did not mediate the association with cognitive functioning. CONCLUSIONS: MDD is associated with more impaired information processing speed and executive functioning & attention, and overall cognitive impairment. Furthermore, MDD was associated with CSVD in participants without type 2 diabetes, but this association did not explain an impaired cognitive profile.

The association of hyperglycaemia and insulin resistance with incident depressive symptoms over 4 years of follow-up: The Maastricht Study.

AIMS/HYPOTHESIS: Depression is twice as common in individuals with type 2 diabetes as in the general population. However, it remains unclear whether hyperglycaemia and insulin resistance are directly involved in the aetiology of depression. Therefore, we investigated the association of markers of hyperglycaemia and insulin resistance, measured as continuous variables, with incident depressive symptoms over 4 years of follow-up. METHODS: We used data from the longitudinal population-based Maastricht Study (n = 2848; mean age 59.9 ± 8.1 years, 48.8% women, 265 incident depression cases, 10,932 person-years of follow-up). We assessed hyperglycaemia by fasting and 2 h post-load OGTT glucose levels, HbA1c and skin autofluorescence (reflecting AGEs) at baseline. We used the Matsuda insulin sensitivity index and HOMA-IR to calculate insulin resistance at baseline. Depressive symptoms (nine-item Patient Health Questionnaire score ≥10) were assessed at baseline and annually over 4 years. We used Cox regression analyses, and adjusted for demographic, cardiovascular and lifestyle risk factors. RESULTS: Fasting plasma glucose, 2 h post-load glucose and HbA1c levels were associated with an increased risk for incident depressive symptoms after full adjustment (HR 1.20 [95% CI 1.08, 1.33]; HR 1.25 [1.08, 1.44]; and HR 1.22 [1.09, 1.37] per SD, respectively), while skin autofluorescence, insulin sensitivity index and HOMA-IR were not (HR 0.99 [0.86, 1.13]; HR 1.02 [0.85, 1.25]; and HR 0.93 [0.81, 1.08], per SD, respectively). CONCLUSIONS/INTERPRETATION: The observed temporal association between hyperglycaemia and incident depressive symptoms in this study supports the presence of a mechanistic link between hyperglycaemia and the development of depressive symptoms. Graphical abstract.

Association of Markers of Microvascular Dysfunction With Prevalent and Incident Depressive Symptoms: The Maastricht Study.

The etiology of late-life depression (LLD) is still poorly understood. Microvascular dysfunction (MVD) has been suggested to play a role in the etiology of LLD, but direct evidence of this association is scarce. The aim of this study was to investigate whether direct and indirect markers of early microvascular dysfunction are associated with prevalent and incident LLD in the population-based Maastricht Study cohort. We measured microvascular dysfunction at baseline by use of flicker light-induced retinal vessel dilation response (Dynamic Vessel Analyzer), heat-induced skin hyperemic response (laser- Doppler flowmetry), and plasma markers of endothelial dysfunction (endothelial dysfunction; sICAM-1 [soluble intercellular adhesion molecule-1], sVCAM-1 [soluble vascular adhesion molecule-1], sE-selectin [soluble E-selectin], and vWF [Von Willebrand Factor]). Depressive symptoms were assessed with the 9-item Patient Health Questionnaire (PHQ-9) at baseline and annually over 4 years of follow-up (n=3029; mean age 59.6±8.2 years, 49.5% were women, n=132 and n=251 with prevalent and incident depressive symptoms [PHQ-9≥10]). We used logistic, negative binominal and Cox regression analyses, and adjusted for demographic, cardiovascular, and lifestyle factors. Retinal venular dilatation and plasma markers of endothelial dysfunction were associated with the more prevalent depressive symptoms after full adjustment (PHQ-9 score, RR, 1.05 [1.00-1.11] and RR 1.06 [1.01-1.11], respectively). Retinal venular dilatation was also associated with prevalent depressive symptoms (PHQ-9≥10; odds ratio, 1.42 [1.09-1.84]), after full adjustment. Retinal arteriolar dilatation and plasma markers of endothelial dysfunction were associated with incident depressive symptoms (PHQ-9≥10; HR, 1.23 [1.04-1.46] and HR, 1.19 [1.05-1.35]), after full adjustment. These findings support the concept that microvascular dysfunction in the retina, and plasma markers of endothelial dysfunction is involved in the etiology of LLD and might help in finding additional targets for the prevention and treatment of LLD.