Comorbid depression is associated with an increased risk of dementia diagnosis in patients with diabetes: a prospective cohort study

Wildfire Smoke Exposure and Incident Dementia

Importance

Long-term exposure to total fine particulate matter (PM2.5) is a recognized dementia risk factor, but less is known about wildfire-generated PM2.5, an increasingly common PM2.5 source.

Objective

To assess the association between long-term wildfire and nonwildfire PM2.5 exposure and risk of incident dementia.

Design, Setting, and Participants

This open cohort study was conducted using January 2008 to December 2019 electronic health record (EHR) data among members of Kaiser Permanente Southern California (KPSC), which serves 4.7 million people across 10 California counties. KPSC members aged 60 years or older were eligible for inclusion. Members were excluded if they did not meet eligibility criteria, if they had a dementia diagnosis before cohort entry, or if EHR data lacked address information. Data analysis was conducted from May 2023 to May 2024.

Exposures

Three-year rolling mean wildfire and nonwildfire PM2.5 in member census tracts from January 2006 to December 2019, updated quarterly and estimated via monitoring and remote-sensing data and statistical techniques.

Main Outcome and Measures

The primary outcome was incident dementia, identified using diagnostic codes in the EHR. Odds of dementia diagnoses associated with 3-year mean wildfire and nonwildfire PM2.5 exposure were estimated using a discrete-time approach with pooled logistic regression. Models adjusted for age, sex, race and ethnicity (considered as a social construct rather than as a biological determinant), marital status, smoking status, calendar year, and census tract-level poverty and population density. Stratified models assessed effect measure modification by age, sex, race and ethnicity, and census tract-level poverty.

Results

Among 1.64 million KPSC members aged 60 years or older during the study period, 1 223 107 members were eligible for inclusion in this study. The study population consisted of 644 766 female members (53.0%). In total, 319 521 members identified as Hispanic (26.0%), 601 334 members identified as non-Hispanic White (49.0%), and 80 993 members received a dementia diagnosis during follow-up (6.6%). In adjusted models, a 1-μg/m3 increase in the 3-year mean of wildfire PM2.5 exposure was associated with an 18% increase in the odds of dementia diagnosis (odds ratio [OR], 1.18; 95% CI, 1.03-1.34). In comparison, a 1-μg/m3 increase in nonwildfire PM2.5 exposure was associated with a 1% increase (OR, 1.01; 95% CI, 1.01-1.02). For wildfire PM2.5 exposure, associations were stronger among members less than 75 years old upon cohort entry, members from racially minoritized subgroups, and those living in high-poverty vs low-poverty census tracts.

Conclusions and Relevance

In this cohort study, after adjusting for measured confounders, long-term exposure to wildfire and nonwildfire PM2.5 over a 3-year period was associated with dementia diagnoses. As the climate changes, interventions focused on reducing wildfire PM2.5 exposure may reduce dementia diagnoses and related inequities.

Depression prevalence, screening, and treatment in adult outpatients with type 1 and type 2 diabetes: A nationally representative cross-sectional study (National Ambulatory Medical Care Survey 2014-2019)

BACKGROUND

Studies have shown that the presence of diabetes or depression may increase the risk for developing the other. The primary objective of this study is to describe the current prevalence of comorbid depression and the rate of screening and treatment for comorbid depression in US adult outpatients with diabetes compared to those without diabetes.

METHODS

We analyzed data from the 2014-2019 National Ambulatory Medical Care Survey. Descriptive statistics, univariate analyses, and multivariable regression models were developed with weighting factors applied.

RESULTS

Depression prevalence is higher in those with diabetes than without diabetes. Females with diabetes have higher rates of depression (15.4%) compared to females without diabetes (13.7%) or males with diabetes (9.1%). Screening rates for depression are extremely low (<6%) in patients with diabetes and without diabetes. Patients with diabetes and depression are less likely to be screened than those with depression alone.

LIMITATIONS

The cross-sectional design of the study cannot establish causality and has inherent limitations in capturing temporal relationships. The reliance on ICD codes limits the scope of diagnosis and underestimates rates of comorbidity if depression is not formally diagnosed. The NAMCS cohort only includes ambulatory visits to office-based physicians, so depression diagnoses and screening rates among patients who visit other health care settings or are not seeing physicians would be underestimated.

CONCLUSIONS

Depression is prevalent in people with diabetes. Screening rates are unacceptably low, indicating a gap in recommended care and underreporting of depression. More routine screening and treatment are necessary to align with guideline-recommended care.

Associations between concussion and more severe TBIs, mild cognitive impairment, and early-onset dementia among military retirees over 40 years

Background and objectives

As the population of U.S. service members (SMs) who have sustained concussions and more severe traumatic brain injuries (TBIs) during military service ages, understanding the long-term outcomes associated with such injuries will provide critical information that may promote long-term assessment, support, and rehabilitation following military service. The objective of this research was to examine whether concussion and more severe TBIs are associated with greater risk of precursors to dementia (i.e., mild cognitive impairment, memory loss), early-onset dementia, and any dementia.

Methods

This study used a retrospective cohort design wherein archival medical and career records from 1980 to 2020 identified U.S. military personnel who retired from military service and their corresponding Tricare-reimbursable medical encounters in inpatient and/or outpatient settings in military treatment facilities and/or purchased care settings both before and after retirement. All military personnel who served on active duty between 1980 and 2020 and were at least 45 years of age by 2020 were eligible for inclusion (N = 6,092,432). Those who were discharged from military service with a retirement designation, and were thus eligible for Tricare for Life, were included in the analytic sample (N = 1,211,972). Diagnoses of concussion and more severe TBI during active duty service recorded in inpatient settings between 1980 and 2020 and in outpatient settings from 2001 to 2020 were identified. Focal outcomes of interest included memory loss, mild cognitive impairment, Alzheimer's, Lewy Body dementia, frontotemporal dementia, and vascular dementia. Dementia diagnoses before age 65 were labeled early-onset.

Results

Those with (vs. without) concussion diagnoses during military service were significantly more likely to be diagnosed with memory loss and mild cognitive impairment and any of the dementias examined. However, they were not at greater risk of being diagnosed with early-onset dementia.

Discussion

Military SMs diagnosed with concussion may be at elevated risk for long-term neurodegenerative outcomes including memory loss, mild cognitive impairment, and dementia. As the population of SMs who sustained TBI during the Global War on Terror continue to age, the prevalence of dementia will increase and may bring a unique burden to the VHA.

The potential role of religiosity, psychological immunity, gender, and age group in predicting the psychological well-being of diabetic patients in Saudi Arabia within the Bayesian framework

This study aimed to investigate the differences in Religiosity (R), Mental Immunity (MI), and Psychological Well-Being (PWB) in patients with diabetes due to gender and age group variables, and to detect the best predictors of PWB in diabetic patients within the Bayesian framework. The study was conducted from May 2022 to February 2023 on a random sample of 186 Saudis diagnosed with diabetes. After obtaining participants' consent, they completed three R, MI, and PWB scales. Bayesian Independent Samples t-test was performed to identify differences, and Bayesian linear regression analysis was used to reveal the best prediction model of PWB. The results of the Bayesian independent samples t-test indicated strong evidence supporting the alternative hypothesis H1, suggesting differences between male and female diabetic patients in R, MI, and PWB, with Bayesian factor values exceeding 10 (8.338×10+23, 1.762×10+25, and 1.866×10+24), and Cohen's δ of (-1.866, -1.934, -1.884). These results indicated that females with diabetes have higher means of R, MI, and PWB compared to males. However, the results also suggested evidence for the null hypothesis H0 of no differences in R, MI, and PWB among diabetic patients due to age group, with Bayesian factor values (0.176, 0.181, and 0.187) less than 1.00 and small Cohen's δ of (-0.034, -0.050, -0.063). Bayesian linear regression analysis detected strong evidence that the model including MI is the best predictive model (BF10 for mental immunity is 1.00 and for the other two models are 0.07 and 4.249×10-16) for the PWB of diabetic patients, however, there is no evidence that the model including R or the interaction between R and MI is the best predictor of PWB for diabetic patients. These findings highlight the need for direct psychological care services for male diabetic patients and the urgent need to enhance IM in diabetic patients to improve their PWB. Furthermore, results recommended that healthcare providers in Saudi Arabia integrate MI interventions into diabetes care programs.

Association between triglyceride-glucose index and depression in patients with type 2 diabetes: A cross-sectional study from NHANES

This cross-sectional study aimed to examine the association between the triglyceride-glucose (TyG) index and the prevalence of depression in individuals with type 2 diabetes. A nationally representative sample of 3225 individuals with type 2 diabetes was enrolled in this study. Multivariable logistic regression models were used to assess the association between the TyG index and depression, adjusting for potential confounding factors. After adjusting for age, gender, BMI, smoking, alcohol consumption, congestive heart failure, and coronary heart disease, a significant positive association was found between the TyG index and the prevalence of depression in individuals with type 2 diabetes (OR = 1.54, 95% CI: 1.21-1.95). Subgroup analyses showed consistent associations across various demographic and clinical subgroups. This study provides evidence of a significant independent positive association between the TyG index and the prevalence of depression in individuals with type 2 diabetes.

Impact of trazodone once-a-day on quality of life and functional recovery in adults with major depressive disorder: A prospective, observational study

BACKGROUND

Health-related quality of life (HRQL) is an important goal for patients with major depressive disorder (MDD), but whether antidepressants improve HRQL in these patients is unclear. Here, we describe the real-world effects of trazodone once-a-day (TzOAD) and selective serotonin reuptake inhibitor (SSRI) treatments on HRQL and functioning in adults with MDD.

METHODS

This 8-week prospective, observational, open-label, multicenter study was conducted in adults with moderate or severe MDD for whom TzOAD or SSRI were prescribed as monotherapy. The primary outcome was life enjoyment and satisfaction assessed via the patient-reported Quality-of-Life Enjoyment and Satisfaction Questionnaire Short Form (Q-LES-Q-SF) from baseline to week 8. Secondary outcomes included change in Q-LES-Q-SF from baseline to weeks 1 and 2; severity of depressive symptoms using the Montgomery Åsberg Depression Rating Scale (MADRS) and sleep disturbance via the PROMIS SF-SD 8b questionnaire at weeks 1, 2, and 8; and overall functioning via the Sheehan Disability Scale (SDS), hedonic capacity using the Snaith-Hamilton Pleasure Scale (SHAPS), and cognitive dysfunction using the Perceived Deficits Questionnaire (PDQ-5) at baseline and week 8.

RESULTS

The study included 208 adults with MDD (mean [SD] age = 50.2 [14.3] years; 68.6% female; 98.4% White). Life enjoyment and satisfaction improved from baseline to week 8 for both treatment groups: Q-LES-Q-SF mean (SD) scores were 27.5 (20.4) for the SSRI group and 39.0 (22.1) for the TzOAD group. Depressive symptoms and sleep disturbances also reduced from baseline to week 8: MADRS (SSRI, -15.7 [8.3]; TzOAD, -21.0 [9.8]); PROMIS SF-SD 8b (SSRI, -9.9 [12.6]; TzOAD, -22.0 [12.6]). Mean change scores in Q-LES-Q-SF, MADRS, and PROMIS SF-SD 8b improved as early as week 1 in both groups. Mean scores also improved from baseline to week 8 on SDS (SSRI, -9.2 [7.4]; TzOAD, -14.3 [7.5]), SHAPS (SSRI, -6.6 [4.3]; TzOAD, -8.3 [4.4]), and PDQ-5 (SSRI, -5.8 [4.5]; TzOAD, -7.7 [5.0]).

CONCLUSIONS

In adults with MDD who received TzOAD or SSRIs, overall and individual HQRL domains improved rapidly and in parallel with improvements in depressive symptoms, with a slightly greater improvement observed in the TzOAD group.

A multi-state analysis of disease trajectories and mental health transitions in patients with type 2 diabetes: A population-based retrospective cohort study utilizing health administrative data

AIMS

To investigate the risk of major depression and dementia in patients with type 2 diabetes, including dementia resulting from depression, and their impact on diabetes-related complications and mortality.

METHODS

We conducted a population-based retrospective cohort study including 11,441 incident cases of diabetes in 2015-2017, with follow-up until 2022. A multi-state survival analysis was performed on a seven-state model with 15 transitions to capture disease progression and onset of mental disorders.

RESULTS

Eight-year probabilities of depression, dementia, diabetes-related complications, and death were 9.7% (95% CI 8.7-10.7), 0.9% (95% CI 0.5-1.3), 10.4% (95% CI 9.5-11.4), and 14.8% (95% CI 13.9-15.7), respectively. Depression increased the risk of dementia up to 3.7% (95% CI 2.0-5.4), and up to 10.3% (95% CI 0.3-20.4) if coupled with diabetes complications. Eight-year mortality was 37.5% (95% CI 33.1-42.0) after depression, 74.1% (95% CI 63.7-84.5) after depression plus complications, 76.4% (95% CI 68.8-83.9) after dementia, and 98.6% (95% CI 96.1-100.0) after dementia plus complications.

CONCLUSIONS

The interconnections observed across depression, dementia, complications, and mortality underscore the necessity for comprehensive and integrated approaches in managing diabetes. Early screening for depression, followed by timely and targeted interventions, may mitigate the risk of dementia and improve diabetes prognosis.

Depression as a Risk Factor for Dementia: A Meta-Analysis

Dementia is a syndrome characterized by the deterioration of cognitive function beyond what is expected. The increased risk of developing this syndrome resulting from established modifiable risk factors, such as depressive episodes, is currently a subject of interest. The aim of this study was to review the scientific evidence that addresses the relationship between depression and dementia. A bibliographic search of the PubMed and PsycInfo databases for articles published over the past 20 years was conducted with the following medical subject heading terms: depression or depressive, dementia, and incidence or cohort studies. After articles meeting the inclusion criteria were selected, relevant moderating variables were grouped as sample characteristics, methodological characteristics, extrinsic characteristics, and outcome variables. The 26 selected studies resulted in a sample comprising 1,760,262 individuals. Statistical analysis revealed a pooled relative risk for the development of dementia of 1.82 (95% CI=1.62-2.06). The primary variables evaluated were the diagnostic methods for depression and dementia and the presence of depression. Other variables, such as mean age, methodological quality of each study, follow-up time, and publication year, were also evaluated. Age was statistically but not clinically significant. No relevant publication bias or alterations in the results were found when accounting for the quality of the studies. It is recommended that new moderating variables be evaluated or that existing variables be reformulated in future studies.

Comorbidity between major depressive disorder and physical diseases: a comprehensive review of epidemiology, mechanisms and management

Populations with common physical diseases - such as cardiovascular diseases, cancer and neurodegenerative disorders - experience substantially higher rates of major depressive disorder (MDD) than the general population. On the other hand, people living with MDD have a greater risk for many physical diseases. This high level of comorbidity is associated with worse outcomes, reduced adherence to treatment, increased mortality, and greater health care utilization and costs. Comorbidity can also result in a range of clinical challenges, such as a more complicated therapeutic alliance, issues pertaining to adaptive health behaviors, drug-drug interactions and adverse events induced by medications used for physical and mental disorders. Potential explanations for the high prevalence of the above comorbidity involve shared genetic and biological pathways. These latter include inflammation, the gut microbiome, mitochondrial function and energy metabolism, hypothalamic-pituitary-adrenal axis dysregulation, and brain structure and function. Furthermore, MDD and physical diseases have in common several antecedents related to social factors (e.g., socioeconomic status), lifestyle variables (e.g., physical activity, diet, sleep), and stressful live events (e.g., childhood trauma). Pharmacotherapies and psychotherapies are effective treatments for comorbid MDD, and the introduction of lifestyle interventions as well as collaborative care models and digital technologies provide promising strategies for improving management. This paper aims to provide a detailed overview of the epidemiology of the comorbidity of MDD and specific physical diseases, including prevalence and bidirectional risk; of shared biological pathways potentially implicated in the pathogenesis of MDD and common physical diseases; of socio-environmental factors that serve as both shared risk and protective factors; and of management of MDD and physical diseases, including prevention and treatment. We conclude with future directions and emerging research related to optimal care of people with comorbid MDD and physical diseases.

State-Level Indicators of Childhood Educational Quality and Incident Dementia in Older Black and White Adults

Importance

Higher educational attainment is associated with reduced dementia risk, but the role of educational quality is understudied, presenting a major evidence gap, especially as it may contribute to racial inequities.

Objective

To evaluate the association between state-level educational quality during childhood and dementia risk.

Design, Setting, and Participants

This cohort study analyzed longitudinal data collected from January 1, 1997, through December 31, 2019 (23-year follow-up period). The sample comprised members of Kaiser Permanente Northern California (KPNC), a large integrated health care delivery system, who completed an optional survey during 1964-1972. Eligible individuals were US born; non-Hispanic Black or non-Hispanic White; aged 65 years or older as of January 1, 1996; were still alive; and did not have a dementia diagnosis or lapse in KPNC membership greater than 90 days between January 1 and December 31, 1996.

Exposures

Historical state-level administrative indicators of school quality (school term length, student-teacher ratio, and attendance rates) linked to participants using birth state and birth year (with a 6-year lag) and divided into tertiles using the pooled sample.

Main Outcomes and Measures

Dementia diagnoses from electronic health records between 1997 and 2019 were analyzed between March 1 and August 31, 2022. The associations of educational quality with incident dementia were estimated using Cox proportional hazards regression models.

Results

Among 21 450 KPNC members who participated in the optional survey, individuals born before availability of educational quality records (n = 87) and missing educational attainment (n = 585) were excluded. The final analytic sample was 20 778 individuals (56.5% women, 43.5% men; mean [SD] age, 74.7 [6.5] years; 18.8% Black; 81.2% White; 41.0% with less than high school education). Among Black individuals, 76.2% to 86.1% (vs 20.8%-23.3% of White individuals) attended schools in states in the lowest educational quality tertiles. Highest (vs lowest) educational quality tertiles were associated with lower dementia risk (student-teacher ratio: hazard ratio [HR], 0.88 [95% CI, 0.83-0.94]; attendance rates: HR, 0.80 [95% CI, 0.73-0.88]; term length: HR, 0.79 [95% CI, 0.73-0.86]). Effect estimates did not differ by race and were not attenuated by adjustment for educational attainment.

Conclusions and Relevance

In this cohort study, lower state-average educational quality was more common among Black individuals and associated with higher dementia risk. Differential investment in high-quality education due to structural racism may contribute to dementia disparities.

Association of Education With Dementia Incidence Stratified by Ethnicity and Nativity in a Cohort of Older Asian American Individuals

IMPORTANCE

High education protects against dementia, but returns on educational attainment may be different across sociodemographic groups owing to various social factors. Asian American individuals are a growing and diverse group, but little research has assessed dementia determinants in this population.

OBJECTIVE

To examine the association of education with dementia in a large cohort of Asian American individuals, stratifying by ethnicity and nativity.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used electronic health record (EHR) and survey data from the Research Program on Genes, Environment, and Health and the California Men's Health Study surveys (2002-2020). Data are from Kaiser Permanente Northern California, an integrated health care delivery system. This study used a volunteer sample who completed the surveys. Participants included Chinese, Filipino, and Japanese individuals who were aged 60 to less than 90 years without a dementia diagnosis in the EHR at the time of the survey (baseline) and who had 2 years of health plan coverage before baseline. Data analysis was performed from December 2021 to December 2022.

EXPOSURES

The main exposure was educational attainment (college degree or higher vs less than a college degree), and the main stratification variables were Asian ethnicity and nativity (born in the US or born outside the US).

MAIN OUTCOMES AND MEASURES

The primary outcome was incident dementia diagnosis in the EHR. Dementia incidence rates were estimated by ethnicity and nativity, and Cox proportional hazards and Aalen additive hazards models were fitted for the association of college degree or higher vs less than a college degree with time to dementia, adjusting for age (timescale), sex, nativity, and an interaction between nativity and college degree.

RESULTS

Among 14 749 individuals, the mean (SD) age at baseline was 70.6 (7.3) years, 8174 (55.4%) were female, and 6931 (47.0%) had attained a college degree. Overall, among individuals born in the US, those with a college degree had 12% lower dementia incidence (HR, 0.88; 95% CI, 0.75-1.03) compared with those without at least a college degree, although the confidence interval included the null. The HR for individuals born outside the US was 0.82 (95% CI, 0.72-0.92; P = .46 for the college degree by nativity interaction). The findings were similar across ethnicity and nativity groups except for Japanese individuals born outside the US.

CONCLUSIONS AND RELEVANCE

These findings suggest that college degree attainment was associated with lower dementia incidence, with similar associations across nativity. More work is needed to understand determinants of dementia in Asian American individuals and to elucidate mechanisms linking educational attainment and dementia.

Relation Between Diabetes and Psychiatric Disorders

Depression, anxiety, and schizophrenia are all things that have been found to be linked to the mental health of diabetics. When combined with particular mental health conditions, the management of diabetes might become very challenging. The management of diabetes requires the patient to be actively involved and is contingent on the patient's adherence to prescribed lifestyle modifications, self-monitoring, and medication. Patients who struggle to keep their mental health concerns under control are more likely to have trouble managing their diabetes on their own. People who have diabetes, because it is one of the most cognitively and behaviorally taxing chronic medical conditions, may be especially susceptible to developing mental health disorders. It is more prevalent in those who suffer from mental problems than it is in the general population. Diabetics frequently struggle with a variety of mental health conditions, including but not limited to schizophrenia, anxiety, and depression. Diagnosing and treating mental health disorders is an important component of diabetes treatment that can be accomplished through the collaborative efforts of members of a multidisciplinary team. Patients who fall into this category can benefit from a wide range of services provided by pharmacists who work with them, including individual assessments, joint goal-setting, skill development, ongoing monitoring, and medication management. These services are designed to help patients feel better and function better.

Psychological Wellbeing of Diabetic Individuals, Prediabetics, and Non-diabetics: A Population-Based Study in Saudi Arabia

Background

The increased burden of diabetes affects the quality of life, including psychosocial problems. The study aims to compare the psychological well-being of individuals who are prediabetic, diabetic, or non-diabetic.

Methods

A cross-sectional exploratory study was conducted from January to June 2016 (n = 1,019) in Al Kharj, Saudi Arabia. After consent and questionnaires were filled out, trained staff took blood samples followed by anthropometry. Chi-squared tests, one-way ANOVA, and multiple linear regression analyses were conducted to examine the association between diabetes classes defined by HbA1c cut-off levels set by the American Diabetes Association (three categories), individual items, and total score in general health questionnaire (GHQ). An ROC curve was plotted for the total GHQ-12 score against HbA1c.

Findings

The mean GHQ score for psychological distress was significantly higher (F = 6.569, P = 0.038) in the diabetics (mean = 14.7) and the prediabetics (12.4) than in the non-diabetics (10.71). Four out of six positive GHQ items and three out of six negative GHQ items significantly differed among the three classes of diabetes. The adjusted multivariate analysis revealed that people with diabetes were most likely to report psychological distress compared to non-diabetics (unstandardized beta = 2.414; P = 0.037). The AUC examining the relationship between HBA1c and GHQ scores showed a moderate but statistically insignificant sensitivity/specificity of 0.643 (P = 0.23).

Conclusion

This study demonstrates that psychological wellbeing is substantially poorer among diabetic or prediabetic individuals than non-diabetic individuals. Future longitudinal studies are required to examine a plausible causal relationship between diabetes/prediabetes and psychological distress.

Associations between depression and cognition, mild cognitive impairment and dementia in persons with diabetes mellitus: A systematic review and meta-analysis

AIMS

This systematic review aimed to examine whether persons with diabetes and depression had poorer cognition and higher dementia risk than persons with diabetes only. Moreover, the impact of timing, frequency of depressive episodes throughout life, and antidepressant treatment were examined.

METHODS

PubMed, Embase and PsycINFO were searched to obtain observational studies between August 2015 and June 2021 that examined the association between depression and cognition, mild cognitive impairment or dementia in people with diabetes. Studies published before August 2015 were retrieved from a previous systematic review. Findings were pooled using meta-analyses.

RESULTS

10 out of 19 included articles were appropriate for the meta-analyses. Persons with diabetes and depression experienced greater declines in executive function (SMD = -0.39 (-0.69, -0.08)), language (SMD = -0.80 (-1.52, -0.09)), memory (SMD = -0.63 (-1.12, -0.14)) and overall cognition (SMD = -0.77 (-1.33, -0.20)), and greater dementia risk (HR = 1.82 (1.79, 1.85)) than persons with diabetes only. No significant differences were observed for complex attention. No studies examined the role of timing and frequency of depressive episodes and antidepressant treatment.

CONCLUSION

In persons with diabetes, depression is associated with worse cognition and higher dementia risk. The potential mitigating effect of antidepressant treatment remains unclear.

Depression Symptoms in Patients with Diabetic Peripheral Neuropathy

AIM

The study aimed to investigate the possible relationship between diabetic peripheral neuropathy (DPN) and the development of depressive symptoms in patients with type 2 diabetes mellitus (T2D).

METHODS

A comparative non-experimental study was conducted. Ninety-five T2D individuals aged 65 years and more were recruited. The sample was divided into two groups: 50 participants with T2D and without DPN and 45 participants with T2D and DPN. The Patient Health Questionnaire 9 (PHQ-9) was used to collect information about low mood and depression symptoms in the subjects recruited.

RESULTS

Participants with DPN recorded higher scores on PHQ-9 than those with T2D only. The mean PHQ-9 score for the DPN group (6.09) was significantly higher than that for the T2D only group (2.24) (p < 0.001). Participants with DPN were more likely to have mild to moderate or moderately severe low mood and depression symptoms than T2D only participants who exhibited minimal to no low mood and depressive symptoms.

CONCLUSIONS

The association between DPN and depression is confirmed by this study, with significant depressive symptoms found in patients with neuropathy when compared to diabetes patients with no neurological complications. It is therefore important that discomfort and emotional problems caused by DPN should be taken seriously and addressed closely in the management of DPN in order to prevent depression. Also, a change in screening practices to identify patients with diabetes and depressive symptoms is required.

Effects of Exercise Intervention on Type 2 Diabetes Patients With Abdominal Obesity and Low Thigh Circumference (EXTEND): Study Protocol for a Randomized Controlled Trial

INTRODUCTION

Type 2 diabetes patients have abdominal obesity and low thigh circumference. Previous studies have mainly focused on the role of exercise in reducing body weight and fat mass, improving glucose and lipid metabolism, with a lack of evaluation on the loss of muscle mass, diabetes complications, energy metabolism, and brain health. Moreover, whether the potential physiological benefit of exercise for diabetes mellitus is related to the modulation of the microbiota-gut-brain axis remains unclear. Multi-omics approaches and multidimensional evaluations may help systematically and comprehensively correlate physical exercise and the metabolic benefits.

METHODS AND ANALYSIS

This study is a randomized controlled clinical trial. A total of 100 sedentary patients with type 2 diabetes will be allocated to either an exercise or a control group in a 1:1 ratio. Participants in the exercise group will receive a 16-week combined aerobic and resistance exercise training, while those in the control group will maintain their sedentary lifestyle unchanged. Additionally, all participants will receive a diet administration to control the confounding effects of diet. The primary outcome will be the change in body fat mass measured using bioelectrical impedance analysis. The secondary outcomes will include body fat mass change rate (%), and changes in anthropometric indicators (body weight, waist, hip, and thigh circumference), clinical biochemical indicators (glycated hemoglobin, blood glucose, insulin sensitivity, blood lipid, liver enzyme, and renal function), brain health (appetite, mood, and cognitive function), immunologic function, metagenomics, metabolomics, energy expenditure, cardiopulmonary fitness, exercise-related indicators, fatty liver, cytokines (fibroblast growth factor 21, fibroblast growth factor 19, adiponectin, fatty acid-binding protein 4, and lipocalin 2), vascular endothelial function, autonomic nervous function, and glucose fluctuation.

DISCUSSION

This study will evaluate the effect of a 16-week combined aerobic and resistance exercise regimen on patients with diabetes. The results will provide a comprehensive evaluation of the physiological effects of exercise, and reveal the role of the microbiota-gut-brain axis in exercise-induced metabolic benefits to diabetes.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn/searchproj.aspx, identifier ChiCTR2100046148.

Association of Type 1 Diabetes and Hypoglycemic and Hyperglycemic Events and Risk of Dementia

OBJECTIVE

To determine whether severe hypoglycemic and hyperglycemic events are associated with longitudinal dementia risk in older adults with type 1 diabetes.

METHODS

A longitudinal cohort study followed up 2,821 members of an integrated health care delivery system with type 1 diabetes from 1997 to 2015. Hypoglycemic and hyperglycemic events requiring emergency room or hospitalization were abstracted from medical records beginning January 1, 1996, through cohort entry. Participants were followed up for dementia diagnosis through September 30, 2015. Dementia risk was examined with Cox proportional hazard models adjusted for age (as time scale), sex, race/ethnicity, hemoglobin A1c, depression, stroke, and nephropathy.

RESULTS

Among 2,821 older adults (mean age 56 years) with type 1 diabetes, 398 (14%) had a history of severe hypoglycemia, 335 (12%) had severe hyperglycemia, and 87 (3%) had both. Over a mean 6.9 years of follow-up, 153 individuals (5.4%) developed dementia. In fully adjusted models, individuals with hypoglycemic events had 66% greater risk of dementia than those without a hypoglycemic event (hazard ratio [HR] 1.66, 95% confidence interval [CI] 1.09, 2.53), while those with hyperglycemic events had >2 times the risk (HR 2.11, 95% CI 1.24, 3.59) than those without a hyperglycemic event. There was a 6-fold greater risk of dementia in individuals with both severe hypoglycemia and hyperglycemia vs those with neither (HR 6.20, 95% CI 3.02, 12.70).

CONCLUSIONS

For older individuals with type 1 diabetes, severe hypoglycemic and hyperglycemic events are associated with increased future risk of dementia.

Participant education, spousal education and dementia risk in a diverse cohort of members of an integrated health care delivery system in Northern California

OBJECTIVE

The role of spousal education on dementia risk and how it may differ by gender or race/ethnicity is unknown. This study examines the association between one's own education separate from and in conjunction with spousal education and risk of dementia.

DESIGN

Cohort.

SETTING

Kaiser Permanente Northern California (KPNC), an integrated health care delivery system.

PARTICIPANTS

8835 members of KPNC who were aged 40-55, married and reported own and spousal education in 1964-1973.

PRIMARY OUTCOME MEASURE

Dementia cases were identified through medical records from 1 January 1996 to 30 September 2017.

METHODS

Own and spousal education was self-reported in 1964-1973 and each was classified as four indicator variables (≤high school, trade school/some college, college degree and postgraduate) and as ≥college degree versus <college degree. Age as timescale weighted Cox proportional hazard models adjusted for demographics and health indicators evaluated associations between participant education, spousal education and dementia risk overall and by gender and race/ethnicity.

RESULTS

The cohort was 37% non-white, 46% men and 30% were diagnosed with dementia during follow-up from 1996 to 2017 (mean follow-up=12.7 years). Greater participant education was associated with lower dementia risk independent of spousal education, demographics and health indicators. Greater spousal education was associated with lower dementia adjusting for demographics but became non-significant after further adjustment for participant education. The same pattern was seen for spousal education ≥college degree (not adjusting for participant education HR_{spousal education≥college degree}=0.83 (95% CI: 0.76 to 0.90); adjusting for participant education HR_{spousal education≥college degree}=0.92 (95% CI: 0.83 to 1.01)). These associations did not vary by gender or race/ethnicity.

CONCLUSION

In a large diverse cohort, we found that higher levels of participant's own education were associated with lower dementia risk regardless of spousal education. An inverse association between spousal education and dementia risk was also present, however, the effects became non-significant after adjusting for participant education.

Gray Matter Abnormalities in Type 1 and Type 2 Diabetes: A Dual Disorder ALE Quantification

Aims/hypothesis: Diabetes mellitus (DM) is associated with comorbid brain disorders. Neuroimaging studies in DM revealed neuronal degeneration in several cortical and subcortical brain regions. Previous studies indicate more pronounced brain alterations in type 2 diabetes mellitus (T2DM) than in type 1 diabetes mellitus (T1DM). However, a comparison of both types of DM in a single analysis has not been done so far. The aim of this meta-analysis was to conduct an unbiased objective investigation of neuroanatomical differences in DM by combining voxel-based morphometry (VBM) studies of T1DM and T2DM using dual disorder anatomical likelihood estimation (ALE) quantification.

Methods: PubMed, Web of Science and Medline were systematically searched for publications until June 15, 2020. VBM studies comparing gray matter volume (GMV) differences between DM patients and controls at the whole-brain level were included. Study coordinates were entered into the ALE meta-analysis to investigate the extent to which T1DM, T2DM, or both conditions contribute to gray matter volume differences compared to controls.

Results: Twenty studies (comprising of 1,175 patients matched with 1,013 controls) were included, with seven studies on GMV alterations in T1DM and 13 studies on GMV alterations in T2DM. ALE analysis revealed seven clusters of significantly lower GMV in T1DM and T2DM patients relative to controls across studies. Both DM subtypes showed GMV reductions in the left caudate, right superior temporal lobe, and left cuneus. Conversely, GMV reductions associated exclusively with T2DM (>99% contribution) were found in the left cingulate, right posterior lobe, right caudate and left occipital lobe. Meta-regression revealed no significant influence of study size, disease duration, and HbA1c values.

Conclusions/interpretation: Our findings suggest a more pronounced gray matter atrophy in T2DM compared to T1DM. The increased risk of microvascular or macrovascular complications, as well as the disease-specific pathology of T2DM may contribute to observed GMV reductions.

Systematic Review Registration: [PROSPERO], identifier [CRD42020142525].

Depression as a risk factor for dementia in older people with type 2 diabetes and the mediating effect of inflammation

AIMS/HYPOTHESIS

We aimed to determine the association of depression with dementia risk in people with type 2 diabetes, and to explore the possible mediating role of inflammation in this relationship.

METHODS

The Edinburgh Type 2 Diabetes Study is a prospective cohort of 1066 men and women with type 2 diabetes aged 60-75 years. Cox proportional hazards regression analysis was used to investigate the association between depression, assessed at baseline, and subsequent risk of dementia over 10 years. Depression was defined using the Hospital Anxiety and Depression Scale, while incident dementia was defined using medical records, prescription data and death certificates. The potential mediating effect of systemic inflammation was assessed by adjusting models for a generalised inflammation factor, derived from four inflammatory markers measured at baseline (C-reactive protein, IL-6, TNF-α and fibrinogen), and carrying out an exploratory mediation analysis.

RESULTS

Dementia developed in 105 participants over a median follow-up of 10.6 years. After adjusting for age and sex, depression was associated with over a 2.5-fold increase in risk of dementia (HR 2.59 [95% CI 1.62, 4.15]). Additional adjustment for the generalised inflammation factor and other covariates did not attenuate the size of association between depression and incident dementia and mediation analysis showed that it was not a mediator. Adjusted logistic regression models showed cross-sectional associations of C-reactive protein and IL-6 with depression.

CONCLUSIONS/INTERPRETATION

Depression is an important risk factor for dementia in people with type 2 diabetes. Some inflammatory markers were associated with depression, but systemic inflammation does not appear to mediate the relationship between depression and dementia. Graphical abstract.

Breast Arterial Calcification Is Not Associated with Mild Cognitive Impairment or Incident All-Cause Dementia Among Postmenopausal Women: The MINERVA Study

Background: Since vascular risk factors are implicated in cognitive decline, and breast arterial calcification (BAC) is related to vascular risk, we postulated that BAC may be associated with cognitive impairment and dementia. Methods: We used a multiethnic cohort of 3,913 asymptomatic women 60-79 years of age recruited after mammography screening at a large health plan in 2012-2015. A BAC mass score (mg) was derived from digital mammograms. Cognitive function was measured at baseline using the Montreal Cognitive Assessment (MoCA) and incident all-cause dementia (n = 49 events; median follow-up = 5.6 years) were ascertained with validated ICD-9 and ICD-10 codes. We used cross-sectional linear regression of MoCA scores on BAC, then multinomial logistic regression predicting mild cognitive impairment not progressing to dementia and incident all-cause dementia and, finally, Cox regression of incident all-cause dementia. Results: No association by linear regression was found between MoCA scores and BAC presence in unadjusted or adjusted analysis. Women with severe (upper tertile) BAC had a MoCA score lower by 0.58 points (standard error [SE] = 0.18) relative to women with no BAC. However, this difference disappeared after multivariate adjustment. No significant associations were found in multinomial logistic regression for either BAC presence or gradation in unadjusted or adjusted analysis. No significant associations were found between BAC presence with incident all-cause dementia (fully adjusted hazard ratio = 0.74; 95% confidence interval: 0.39-1.39). Likewise, no significant association with incident all-cause dementia was noted for BAC gradation. Conclusions: Our results do not support the hypothesis that BAC presence or gradation may contribute to cognitive impairment or development of all-cause dementia.

Risk Factors for Dementia Incidence Based on Previous Results of the Specific Health Checkups in Japan

Dementia is a common disease in elderly people, with its prevalence expanding rapidly worldwide. Longitudinal and cohort studies on lifestyle and health conditions are needed to identify the risk of dementia. This study aimed to identify the risk factors for dementia incidence in Japan and to clarify the strategy for its primary care. In this study, an analysis was performed to investigate the association between the cognitive faculty level of the long-term care certification survey and the previous results of the specific health checkups in Japan. To investigate the risk factor for dementia incidence, a multivariable logistic regression analysis was performed, which showed a significant odds ratio for the incidence of dementia for two items, including abdominal circumference and insulin injections or oral hypoglycemic medications. The findings of our study suggested that a lower abdominal circumference had a higher risk for dementia incidence, and individuals who received insulin injections or oral hypoglycemic medications had a higher risk for dementia incidence based on the results of the health checkups conducted 10 years previously. Further, longer duration study with a larger sample is needed to identify the items from the specific health checkups that are associated with the risk of dementia.

Implications of the Use of Algorithmic Diagnoses or Medicare Claims to Ascertain Dementia

INTRODUCTION

Formal dementia ascertainment with research criteria is resource-intensive, prompting the growing use of alternative approaches. Our objective was to illustrate the potential bias and implications for study conclusions introduced through the use of alternate dementia ascertainment approaches.

METHODS

We compared dementia prevalence and risk factor associations obtained using criterion-standard dementia diagnoses to those obtained using algorithmic or Medicare-based dementia ascertainment in participants of the baseline visit of the Aging, Demographics, and Memory Study (ADAMS), a Health and Retirement Study (HRS) sub-study.

RESULTS

Estimates of dementia prevalence derived using algorithmic or Medicare-based ascertainment differ substantially from those obtained using criterion-standard ascertainment. Use of algorithmic or Medicare-based dementia ascertainment can, but does not always, lead to risk factor associations that substantially differ from those obtained using criterion-standard ascertainment.

DISCUSSION/CONCLUSIONS

Absolute estimates of dementia prevalence should rely on samples with formal dementia ascertainment. The use of multiple algorithms is recommended for risk factor studies when formal dementia ascertainment is not available.

Stressors in Midlife and Risk of Dementia: The Role of Race and Education

BACKGROUND

Posttraumatic stress disorder is associated with increased dementia risk but less is known about stress because of everyday problems in diverse populations.

METHODS

A total of 9605 health care plan members who provided information regarding midlife stressors in 1972 to 1973 (ages, 40 to 55 y) were followed for dementia diagnosis between 1996 and 2017. Cox proportional hazard models evaluated associations between midlife stressors and dementia adjusting for demographics and lifecourse health indicators.

RESULTS

Reporting at least 1 midlife stressor was associated with 17% greater dementia risk [hazard ratio (HR), 1.17; 95% confidence interval (CI),1.07-1.27] versus 0 midlife stressors and 26% increased risk among those with less than equal to high school education (HR, 1.26; 95% CI,1.09-1.44) adjusting for demographics. Compared with whites without stressors, whites with ≥1 stressor had 13% greater dementia risk (HR, 1.13; 95% CI, 1.02-1.24), blacks without stressors 19% greater risk (HR, 1.19; 95% CI,1.08-1.32), and blacks with ≥1 stressors 47% greater risk (HR, 1.47; 95% CI,1.27-1.69) in fully adjusted models. Resource problems were associated with 20% greater risk (HR, 1.20; 95% CI, 1.01-1.42) than interpersonal problems.

CONCLUSION

Reporting ≥1 serious midlife stressor was associated with elevated dementia risk, especially stressors related to resources problems and for those with less than equal to high school education. Everyday stressors can impact brain health over the long term and may contribute to racial inequities in dementia rates, though education can be a mitigating factor.

The Link between Activities of Daily Living and Cortisol in Late-Life Depression

OBJECTIVES

Dysregulated cortisol in older individuals is associated with neurodegeneration and executive dysfunction, among other negative health outcomes. Executive functioning deficits are believed to underlie declines in functioning among older adults. Despite these associations, there is limited research examining the relationship between cortisol and impaired functional status.

METHODS

The present study examined the relationship between cortisol and functional status in a community sample of 51 older adults with depression. Pearson correlations and ordinal regressions were used to determine whether greater cortisol dysregulation was associated with ADL and IADL impairment.

RESULTS

Results indicated that individuals who had higher levels of cortisol also tended to demonstrate greater functional deficits. These findings remained true when functional status was measured by either a clinician-rated tool or a self-report measure.

CONCLUSIONS

The results of this study provide preliminary support for the hypothesis that elevated cortisol, in the context of depression, is associated with functional status deficits in older adults.

CLINICAL IMPLICATIONS

Findings from this study begin to fill the gap in research examining the relationship between cortisol and functional impairment in older adults and suggest that unique information can be gathered with the use of different functional status measures.

Early Midlife Pulmonary Function and Dementia Risk

BACKGROUND

Poor pulmonary function (PPF) is associated with increased risk of dementia, yet it is unclear if PPF in early adulthood to midlife increases risk, independent of smoking and subsequent vascular disease.

OBJECTIVE

This study evaluated the association between multiple markers of PPF in early adulthood to midlife and long-term risk of dementia.

METHODS

We evaluated 27,387 members of an integrated health care system with forced expiratory volume in 1, 2 seconds, and vital capacity collected from 1964 to 1973 (mean age=41.8±4.2 y). Associations of PPF with dementia diagnoses from January 1, 1996 to September 30, 2015 were evaluated with Cox proportional hazards models adjusted for demographics, height, body mass index, hypertension, smoking status, diabetes, stroke, and heart failure.

RESULTS

In total, 7519 individuals (27%) were diagnosed with dementia. In fully adjusted Cox proportional hazards models, for all PPF measures each liter decrease was associated with a 13% to 14% higher risk of dementia. Compared with the highest quintile, the first quintile of PPF measures were associated with a 24% to 28% increased risk of dementia; second to fourth quintiles showed strong dose-dependent associations. Results were similar when stratified by smoking status.

CONCLUSIONS

In this large, diverse cohort, multiple measures of PPF in early adulthood to midlife were associated with dementia risk independent of smoking and vascular comorbidities.

Personality traits and cognitive function in old-adults with type-2 diabetes

Objectives: Personality may constitute an important domain of influence on cognitive function in old-adults. We assessed the relationship of personality traits and cognitive performance in individuals with Type-2 Diabetes (T2D), and explored possible mediators. Method: The sample includes 377 dementia-free subjects with T2D participating in the Israel Diabetes and Cognitive Decline study who underwent assessment of cognition and personality (mean age 72 ± 4y; 42% females). We assessed the relationships of personality traits with episodic memory, semantic categorization, attention/working memory, executive function and overall cognition using linear regression models adjusting for age, education, sex, BMI, T2D duration, Hemoglobin A1C (HbA1C), hypertension, c-reactive protein, total- to HDL-cholesterol ratio and ApoEɛ4 genotype. A post-hoc mediation analysis was conducted with HbA1C, proportion of days covered (PDC) by T2D prescription claims and depressive symptoms. Results: After adjustment for multiple covariates, high neuroticism levels were associated with poorer performance overall (β= -0.16 ± 0.05; p = 0.001) and with poorer episodic memory, attention/working memory, and semantic categorization (β= -0.14 ± 0.05; p = 0.007, β= -0.12 ± 0.05; p = 0.017 and β= -0.12 ± 0.05; p = 0.018, respectively). High scores on openness to experience were associated with better global cognition (β = 0.11 ± 0.05; p = 0.026), executive functions (β = 0.13 ± 0.05; p = 0.013) and semantic categorization (β = 0.17 ± 0.05; p = 0.001, respectively). Depressive symptoms mediated the association of neuroticism with executive function, and the association of openness with executive function and overall cognition. Conclusion: Personality may play an important role in cognitive health among elderly subjects with T2D. Future studies should address the mechanisms underlying these relationships and specifically the potential role of depressive symptoms which may be in the causal pathway between personality traits and cognitive outcomes.

Depression in type 1 diabetes and risk of dementia

OBJECTIVE

Depression afflicts 14% of individuals with type 1 diabetes (T1D). Depression is a robust risk factor for dementia but it is unknown if this holds true for individuals with T1D, who recently started living to an age conferring dementia risk. We examined if depression is a dementia risk factor among elderly individuals with T1D.

METHODS

3,742 individuals with T1D age ≥50 were followed for dementia from 1/1/96-9/30/2015. Depression, dementia, and comorbidities were abstracted from electronic medical records. Cox proportional hazard models estimated the association between depression and dementia adjusting for demographics, glycosylated hemoglobin, severe dysglycemic epidsodes, stroke, heart disease, nephropathy, and end stage renal disease. The cumulative incidence of dementia by depression was estimated conditional on survival dementia-free to age 55.

RESULTS

Five percent (N = 182) were diagnosed with dementia and 20% had baseline depression. Depression was associated with a 72% increase in dementia (fully adjusted HR = 1.72; 95% CI:1.12-2.65). The 25-year cumulative incidence of dementia was more than double for those with versus without depression (27% vs. 12%).

CONCLUSIONS

For people with T1D, depression significantly increases dementia risk. Given the pervasiveness of depression in T1D, this has major implications for successful aging in this population recently living to old age.

Reproductive period and risk of dementia in a diverse cohort of health care members

OBJECTIVE

Women have >50% greater lifetime risk of dementia than men but the role of female-specific endocrine milieu is not well-understood. This study evaluates associations between indicators of estrogen exposure from women's reproductive period and dementia risk in a large diverse population.

METHODS

We evaluated 15,754 female members (29.9% nonwhite) of Kaiser Permanente with clinical examinations and health survey data from 1964 to 1973 and were members as of January 1, 1996. In midlife (mean age 51.1 years), women reported age at menarche and menopause and hysterectomy status. Reproductive span was calculated as menopause age minus menarche age. Dementia diagnoses were abstracted from January 1, 1996 to September 30, 2017 medical records (mean age at start of dementia follow-up 76.5 years). Cox proportional hazard models evaluated associations between aspects of reproductive span and dementia risk adjusting for demographics and life course health indicators.

RESULTS

Forty-two percent of women developed dementia. Compared to menarche at age 13.0 (mean menarche age), menarche at ≥16 was associated with 23% greater dementia risk (adjusted hazard ratio [HR] 1.23; 95% confidence interval [CI] 1.01-1.50) adjusting for demographics and life course health indicators. Natural menopause at age <47.4 (mean menopause age) was associated with 19% elevated dementia risk (HR 1.19; 95% CI 1.07-1.31). Reproductive spans <34.4 years (mean duration) were associated with 20% elevated dementia risk (HR 1.20; 95% CI 1.08-1.32). Hysterectomies were associated with 8% elevated dementia risk (HR 1.08; 95% CI 1.01-1.16).

CONCLUSION

In this large prospective cohort study, endocrine events signaling less estradiol exposure (i.e., later age at menarche, younger age at menopause, shorter reproductive span, and hysterectomies) were associated with elevated risk of dementia.

Diabetes Mellitus-Related Fractional Glucose Uptake in Men and Women Imaged With 18F-FDG PET-CT

CONTEXT

Cohort studies show that cognitive dysfunction and both vascular and Alzheimer's dementia are more common in patients with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To review and compare brain volume and 18F-fluorodeoxyglucose (FDG) uptake in brain of individuals age 60 to 70 years with or without type 2 diabetes.

DESIGN

We searched 620 medical records for negative 18FDG PET-CT scans obtained during 33 months. Records showing history of cognitive impairment, Alzheimer's disease, neurologic disorders, any history of brain atrophy, or documented cerebral infarction on neuroimaging were excluded from the study.

RESULTS

A total of 119 medical records met the inclusion criteria. Data from 63 women and 56 men (without T2DM, 86; with T2DM, 33) were analyzed. Brain volume was larger in men than women (mean ± SD, 1411 ± 225 cm3 vs 1325 ± 147 cm3, respectively; P = 0.02), but men had a significantly lower fractional glucose uptake (SUVgluc), calculated as fasting blood glucose × SUVmax. [median (minimum, maximum), 63.6 (34.6, 126.6) vs 70.0 (36.4, 134.3); P = 0.02]. Brain volume was also larger in persons without T2DM than in those with T2DM (1392 ± 172 cm3 vs 1269 ± 183 cm3; P < 0.001), but SUVgluc was similar between these groups. Brain volume correlated with SUVgluc in both men and women overall (P < 0.001) but not in men and women with T2DM (P = 0.20 and 0.36, respectively).

CONCLUSION

In men without T2DM, median brain volume was larger and fractional glucose uptake was less than in women without T2DM. In men and women with T2DM, brain volume and fractional glucose uptake were similar. The findings support the hypothesis that fractional glucose uptake becomes impaired in men with T2DM.

Incidence of dementia after age 90 in a multiracial cohort

INTRODUCTION

Little is known about dementia incidence in diverse populations of oldest-old, the age group with highest dementia incidence.

METHODS

Incident dementia diagnoses from 1/1/2010 to 9/30/2015 were abstracted from medical records for 2350 members of an integrated health care system in California (n = 1702 whites, n = 375 blacks, n = 105 Latinos, n = 168 Asians) aged ≥90 in 2010. We estimated race/ethnicity-specific age-adjusted dementia incidence rates and implemented Cox proportional hazards models and Fine and Gray competing risk of death models adjusted for demographics and comorbidities in midlife and late-life.

RESULTS

Dementia incidence rates (n = 771 cases) were lowest among Asians (89.9/1000 person-years), followed by whites (96.9/1000 person-years), Latinos (105.8/1000 person-years), and blacks (121.5/1000 person-years). Cox regression and competing risk models estimated 28% and 36% higher dementia risk for blacks versus whites adjusting for demographics and comorbidities.

DISCUSSION

Patterns of racial/ethnic disparities in dementia seen in younger older adults continue after the age of 90 years, though smaller in magnitude.

Risk of dementia associated with cardiometabolic abnormalities and depressive symptoms: a longitudinal cohort study using the English longitudinal study of ageing

OBJECTIVES

Depression and cardiometabolic abnormalities are independently associated with a high risk of dementia. This study aimed to examine the association of comorbid depressive symptoms and cardiometabolic abnormalities with risk of dementia.

METHODS

The sample comprised 4859 participants aged 50 or older without baseline dementia who took part in the English Longitudinal Study of Ageing (waves 2-7). Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression tool. Cardiometabolic abnormalities were defined as three or more cardiometabolic risk factors (inflammation, central obesity, raised triglycerides, low high-density lipoprotein [HDL] cholesterol, hypertension, and hyperglycaemia or diabetes). Participants were classified into four groups based on presence of depressive symptoms and cardiometabolic abnormalities. Results were analysed using the Cox proportional hazards regression adjusted for covariates.

RESULTS

A total of 216 cases of incident dementia were reported over 10 years of follow-up. The group with high depressive symptoms only had an increased hazard of developing incident dementia during follow-up (HR = 2.68; 95%CI, 1.70-4.23), which was attenuated after adjustment for baseline cognition. No evidence was found for an association of overall cardiometabolic abnormalities with incident dementia; though hyperglycaemia, hypertension, and abdominal obesity with depressive symptoms had an unadjusted association with incident dementia. Only low-HDL cholesterol with depressive symptoms had an adjusted association with incident dementia (HR = 0.18; 95%CI, 0.04-0.75).

CONCLUSIONS

This work confirms depressive symptoms as a risk factor for incident dementia. However, low HDL-cholesterol with depressive symptoms may be protective against dementia, though more work is required to confirm this association.

Depressive symptoms and quality of life after screening for cognitive impairment in patients with type 2 diabetes: observations from the Cog-ID cohort study

OBJECTIVES

To assess changes in depressive symptoms and health-related quality of life (HRQOL) after screening for cognitive impairment in people with type 2 diabetes.

DESIGN

A prospective cohort study, part of the Cognitive Impairment in Diabetes (Cog-ID) study.

SETTING

Participants were screened for cognitive impairment in primary care. People suspected of cognitive impairment (screen positives) received a standardised evaluation at a memory clinic.

PARTICIPANTS

Participants ≥70 years with type 2 diabetes were included in Cog-ID between August 2012 and September 2014, the current study includes 179 patients; 39 screen positives with cognitive impairment, 56 screen positives without cognitive impairment and 84 participants not suspected of cognitive impairment during screening (screen negatives).

OUTCOME MEASURES

Depressive symptoms and HRQOL assessed with the Center for Epidemiologic Studies Depression Scale (CES-D), 36-Item Short-Form Health Survey, European Quality of Life-5 Dimensions questionnaire and the EuroQol Visual Analogue Scale. Outcomes were assessed before the screening, and 6 and 24 months after screening. An analysis of covariance model was fitted to assess differences in score changes among people diagnosed with cognitive impairment, screen negatives and screen positives without cognitive impairment using a factor group and baseline score as a covariate.

RESULTS

Of all participants, 60.3% was male, mean age was 76.3±5.0 years, mean diabetes duration 13.0±8.5 years. At screening, participants diagnosed with cognitive impairment had significantly more depressive symptoms and a worse HRQOL than screen negatives. Scores of both groups remained stable over time. Screen positives without cognitive impairment scored between the other two groups at screening, but their depressive symptoms decreased significantly during follow-up (mean CES-D: -3.1 after 6 and -2.1 after 24 months); their HRQOL also tended to improve.

CONCLUSIONS

Depressive symptoms are common in older people with type 2 diabetes. Screening for and a subsequent diagnosis of cognitive impairment will not increase depressive symptoms.

Pathophysiological Mechanisms Linking Type 2 Diabetes and Dementia: Review of Evidence from Clinical, Translational and Epidemiological Research

BACKGROUND

Type 2 diabetes represents an increasing health burden world-wide and its prevalence in particularly higher in elderly population. Consistent epidemiological evidence suggests an increased risk of dementia associated to type 2 diabetes; the mechanisms underlying these associations, however, remain unclear.

OBJECTIVE

The study aims to review epidemiological, clinical and pre-clinical data that weigh on pathophysiological links, mechanisms of disease and associations between type 2 diabetes and dementia to identify areas of opportunity for future research.

METHODS

We searched the following electronic bibliographic databases: PUBMED, EMBASE, SCIELO, MEDLINE and OVID for clinical, translational and epidemiological research literature that summarize diabetes-related risk factors for dementia, metabolic and neurological changes associated to T2D, evidence of therapeutic approaches in type 2 diabetes and its pathophysiological implications for dementia.

RESULTS

Type 2 diabetes mellitus increases risk for all-cause dementia, vascular dementia and Alzheimer's disease. The most evaluated mechanisms linking both disorders in pre-clinical studies include an increase in neuronal insulin resistance, impaired insulin signaling, pro-inflammatory state, mitochondrial dysfunction and vascular damage which increase deposition of β-amyloid, tau proteins and GSK3β, leading to an earlier onset of dementia in individuals with impairment in the glucose metabolism. Neuroimaging and neuropathology evidence linking cerebrovascular lesions, neurodegeneration and particularly small-vessel disease in the onset of dementia is consistent with the increased risk of incident dementia in type 2 diabetes, but consistent evidence of AD-related pathology is scarce. Epidemiological data shows increased risk of dementia related to hypoglycemic episodes, glycemic control, metabolic syndrome, insulin resistance and genetic predisposition, but the evidence is not consistent and statistical analysis might be affected by inconsistent covariate controlling. Therapeutic approaches for T2D have shown inconsistent result in relation to dementia prevention and delay of cognitive decline; lifestyle intervention, particularly physical activity, is a promising alternative to ameliorate the impact of disability and frailty on T2D-related dementia.

CONCLUSION

Vascular disease, inflammation and impaired brain insulin signaling might occur in T2D and contribute to dementia risk. Evidence from epidemiological studies has not consistently reported associations that could integrate a unified mechanism of disease in humans. Evaluation of the effect of antidiabetic medications and non-pharmacological interventions in dementia prevention in type 2 diabetes is promising but has thus far offered inconsistent results.

Birth in High Infant Mortality States and Dementia Risk in a Cohort of Elderly African American and White Health Care Members

IMPORTANCE

Birth in areas with high infant mortality rates (IMRs) has been linked to worse long-term health outcomes, yet it is completely unknown if it impacts dementia risk.

METHODS

In total 6268 health care members were followed for dementia diagnosis from 1996 to 2015. Birth state IMRs from 1928 were ranked into quartile (worst IMRs quartile range, whites: 69 to 129 deaths/1000 live births, Non-whites: 129 to 277 deaths/1000 live births). Cox proportional hazard models estimated the dementia risk associated with birth state IMR quartile adjusting for demographics and lifecourse health indicators.

RESULTS

Compared with whites born outside of states in the worst IMR quartile, African Americans born in states in the worst IMR quartile had 92% increased dementia risk (HR=1.92; 95% CI: 1.42, 2.59), and African Americans born outside those states had 36% increased risk (HR=1.36; 95% CI: 1.20, 1.53). There was no association between birth state IMR and dementia risk among whites.

CONCLUSIONS

Birth in states with the highest rates of infant mortality was associated with elevated dementia risk among African Americans but not whites. The large absolute difference in IMRs likely reflects harsher early childhood conditions experienced by African Americans. These findings suggest that childhood conditions may play a role in racial disparities in dementia rates.

Depression and diabetes

The comorbidity of mental and physical disorders is a major challenge for health care worldwide. Its prevalence is increasing and is likely to continue to grow due to the increase in life expectancy and a variety of other reasons. The comorbidity of depression and diabetes can be seen as a prototypical example of mental/physical comorbidity. The prevalence of both conditions is growing, and depression is twice as frequent in people with diabetes compared with those without diabetes. Health services are by and large inadequately prepared to deal with comorbid depression and diabetes, and the increasing specialization (and fragmentation) of medicine will probably make things worse. This paper reviews the epidemiology and risk factors of the comorbidity of depression and diabetes and describes areas that should be given attention in order to reduce problems arising as a result of the comorbidity of these two conditions.

Traumatic brain injury associated with dementia risk among people with type 1 diabetes

OBJECTIVE

To examine the association between traumatic brain injury (TBI) and dementia risk among a cohort of middle-aged and elderly individuals with type 1 diabetes (T1D).

METHODS

We evaluated 4,049 members of an integrated health care system with T1D ≥50 years old between January 1, 1996, and September 30, 2015. Dementia and TBI diagnoses throughout the study period were abstracted from medical records. Cox proportional hazards models estimated associations between time-dependent TBI and dementia adjusting for demographics, HbA1c, nephropathy, neuropathy, stroke, peripheral artery disease, depression, and dysglycemic events. Fine and Gray regression models evaluated the association between baseline TBI and dementia risk accounting for competing risk of death.

RESULTS

A total of 178 individuals (4.4%) experienced a TBI and 212 (5.2%) developed dementia. In fully adjusted models, TBI was associated with 3.6 times the dementia risk (hazard ratio [HR] 3.64; 95% confidence interval [CI] 2.34, 5.68). When accounting for the competing risk of death, TBI was associated with almost 3 times the risk of dementia (HR 2.91; 95% CI 1.29, 5.68).

CONCLUSION

This study demonstrates a marked increase in risk of dementia associated with TBI among middle-aged and elderly people with T1D. Given the complexity of self-care for individuals with T1D, and the comorbidities that predispose them to trauma and falls, future work is needed on interventions protecting brain health in this vulnerable population, which is now living to old age.

Prevalence and factors associated with memory disturbance and dementia after acute ischemic stroke

Prevalence and risk factors associated with memory disturbance and dementia were determined in acute ischemic stroke (AIS) patients in hospitals before discharge, three and six months after stroke. A prospective cohort study was conducted during January-December 2017 with 401 AIS patients admitted to Srinagarind Hospital, Khon Kaen Hospital and Chum Phae Hospital, Khon Kaen, Thailand. The demographics and clinical characteristics, previous illness and past medical history, and laboratory test results of the patients were collected from the medical records, while depression screening, NIH stroke scale (NIHSS) scoring and mini mental state examination (MMSE) were performed using particular medical record forms. The prevalence of memory disturbance and dementia was 56.6, 41.6 and 38.2% before discharge, three and six months after stroke, respectively. Based on logistic regression analysis, age, education and stroke severity were the risk factors associated with the studied disorders before discharge and three months after stroke. Meanwhile, age and education were the risk factors for six months after stroke. Our findings suggested that the prevalence of memory disturbance and dementia remained high at all study periods.

Heterogeneity in 14-year Dementia Incidence Between Asian American Subgroups

BACKGROUND

Asian Americans are a rapidly growing and diverse population. Prior research on dementia among Asian Americans focused on Japanese Americans or Asian Americans overall, although marked differences in cardiometabolic conditions between subgroups have been documented.

MATERIALS AND METHODS

We compared dementia incidence among 4 Asian American subgroups (n=8384 Chinese; n=4478 Japanese; n=6210 Filipino; n=197 South Asian) and whites (n=206,490) who were Kaiser Permanente Northern California members aged 64 years and above with no dementia diagnoses as of January 1, 2000. Dementia diagnoses were collected from medical records January 1, 2000 to December 31, 2013. Baseline medical utilization and comorbidities (diabetes, depression, hypertension, stroke, cardiovascular disease) were abstracted from medical records January 1, 1996 to December 31, 1999. We calculated age-standardized dementia incidence rates and Cox models adjusted for age, sex, medical utilization, and comorbidities.

RESULTS

Mean baseline age was 71.7 years; mean follow-up was 9.6 years. Age-standardized dementia incidence rates were higher among whites than "All Asian-Americans" or any subgroup. Compared with Chinese (13.7/1000 person-years), dementia incidence was slightly higher among Japanese [14.8/1000 person-years; covariate-adjusted hazard ratio (adjusted-HR)=1.08; 95% confidence interval (CI), 0.99-1.18] and Filipinos (17.3/1000 person-years; adjusted-HR=1.20; 95% CI, 1.11-1.31), and lower among South Asians (12.1/1000 person-years; adjusted-HR=0.81; 95% CI, 0.53-1.25).

CONCLUSIONS

Future studies are needed to understand how immigration history, social, environmental, and genetic factors contribute to dementia risk in the growing and diverse Asian American population.

Severity of Depression Impacts Imminent Conversion from Mild Cognitive Impairment to Alzheimer's Disease

BACKGROUND

Mild cognitive impairment (MCI) has been suggested to represent a prodromal stage of dementia and to confer a high risk for conversion to dementia Alzheimer's type (DAT).

OBJECTIVES

In this study, we examined the predictive value of depressive symptoms and neuropsychological variables on conversion of MCI to DAT.

METHODS

Neuropsychological and clinical follow-up data of 260 MCI patients seen at the Psychiatric Memory Clinic of the Medical University of Innsbruck between 2005 and 2015 were analyzed retrospectively. Depression was assessed using the Geriatric Depression Scale (GDS). Potential predictors of conversion from MCI to DAT were analyzed by logistic regression analyses and additional survival-analytic methods.

RESULTS

Of the 260 patients (mean age 71.5±7.7 years), 83 (32%) converted to DAT within a mean follow-up time of 3.2±2.2 years and estimated one-year conversion rate of 10.1%. The univariate analysis showed with few exceptions (gender, use of antidepressants, low GDS score) group differences at baseline in patients converted to DAT compared to stable MCI patients. Logistic regression analysis as well as survival analysis revealed moderate to severe depression together with higher age and specific cognitive deficits as predictors of conversion from MCI to DAT.

CONCLUSION

Our results support the predictive value of different neuropsychological measures on the progression of DAT. In addition, we found a strong negative influence of depression on conversion to DAT in MCI patients. These results emphasize the importance of assessing depressive symptoms in the early stages of DAT when evaluating the conversion from MCI to DAT.

Diabetic Retinopathy and Dementia in Type 1 Diabetes

OBJECTIVE

Retinopathy impacts over one-third of those with diabetes mellitus and is associated with impaired cognitive performance and cerebrovascular lesions in middle-aged adults with type 1 diabetes. However, the association between diabetic retinopathy (DR) and risk of dementia in type 1 diabetes is unknown. We investigated the association between DR and incident dementia in a large, elderly population with type 1 diabetes.

METHODS

A cohort of 3742 patients with type 1 diabetes aged 50 years and above was followed from January 1, 1996 to September 30, 2015 for incident dementia. DR diagnoses were identified from electronic medical records. Age as timescale Cox proportional hazard models evaluated associations between time-updated DR and dementia risk. Models were adjusted for demographics, severe glycemic events, glycosylated hemoglobin, and vascular comorbidities.

RESULTS

Among 3742 patients with type 1 diabetes (47% female, 21% nonwhite), 182 (5%) were diagnosed with dementia during a mean follow-up of 6.2 years. No significant association was found between DR and incident dementia in the main analyses [adjusted Hazard Ratio=1.12; 95% confidence interval, 0.82-1.54), nor among subgroup restricted to those aged 60 years and above or 70 years and above.

CONCLUSIONS

DR was not associated with risk of dementia, suggesting that pathophysiological processes underlying dementia may be different in type 1 versus type 2 diabetes.

Cardiometabolic dysregulation and cognitive decline: potential role of depressive symptoms

BACKGROUND

Previous studies have examined associations of cardiometabolic factors with depression and cognition separately. Aims To determine if depressive symptoms mediate the association between cardiometabolic factors and cognitive decline in two community studies.

METHOD

Data for the analyses were drawn from the Rotterdam Study, the Netherlands (n = 2940) and the Whitehall II study, UK (n = 4469).

RESULTS

Mediation analyses suggested a direct association between cardiometabolic factors and cognitive decline and an indirect association through depression: poorer cardiometabolic status at time 1 was associated with a higher level of depressive symptoms at time 2 (standardised regression coefficient 0.07 and 0.06, respectively), which, in turn, was associated with greater cognitive decline between time 2 and time 3 (standardised regression coefficient of -0.15 and -0.41, respectively).

CONCLUSIONS

Evidence from two independent cohort studies suggest an association between cardiometabolic dysregulation and cognitive decline and that depressive symptoms tend to precede this decline. Declaration of interest None.

Mild cognitive impairment and progression to dementia in people with diabetes, prediabetes and metabolic syndrome: a systematic review and meta-analysis

PURPOSE

We aimed to quantify the relative risk of progression from mild cognitive impairment (MCI) to dementia in people with and without diabetes, and with and without the MetS (MetS); and to identify potential modifiers of the risk of progression from MCI to dementia in people with diabetes or MetS.

METHODS

We searched Medline, Embase, PsycINFO, PsycArticles and Web of Science from inception through to 20th March 2018. Where possible, the results from three or more studies were pooled in a meta-analysis, while other findings have been described narratively.

RESULTS

We included 15 articles reporting 12 studies (6865 participants). The overall unadjusted pooled odds ratio for the progression of MCI to dementia in people with diabetes/MetS was 1.67 (95% CI 1.27-2.19); the pooled odds ratio for progression in diabetes + MCI was 1.53 (95% CI 1.20-1.97) and in people with MetS + MCI was 2.95 (95% CI 1.23-7.05). There was moderate heterogeneity in the included studies (I² < 60%). In diabetes, a longer duration of diabetes and the presence of retinopathy were associated with an increased risk of progression, while the use of statins and oral hypoglycaemic agents reduced the risk. Having multiple cardiovascular risk factors was a significant risk factor for progression from MCI to dementia in people with MetS.

CONCLUSIONS

Diabetes and MetS were both associated with an increased incidence of dementia when co-existing with MCI. Intensive cardiovascular risk reduction and lifestyle changes for patients presenting with MCI and diabetes, prediabetes or MetS may be important in reducing incidence of dementia in this high risk population.

Depression in people with type 2 diabetes: current perspectives

Type 2 diabetes mellitus (T2DM) is associated with depressive symptoms, and comorbid depression in those with T2DM has been associated with adverse clinical profiles. Recognizing and addressing psychological symptoms remain significant clinical challenges in T2DM. Possible mediators of the reciprocal relationship between T2DM and depression may include physical activity levels, effectiveness of self-management, distress associated with a new T2DM diagnosis, and frailty associated with advanced diabetes duration. The latter considerations contribute to a "J-shaped" trajectory from the time of diagnosis. There remain significant challenges to screening for clinical risks associated with psychological symptoms in T2DM; poorer outcomes may be associated with major depressive episodes, isolated (eg, anhedonic), or subsyndromal depressive symptoms, depressive-like symptoms more specific to T2DM (eg, diabetes-related distress), apathy or fatigue. In this review, we discuss current perspectives on depression in the context of T2DM with implications for screening and management of these highly comorbid conditions.

Relationship between Insulin Levels and Nonpsychotic Dementia: A Systematic Review and Meta-Analysis

Objectives

To explore the relationship between insulin levels and nonpsychotic dementia.

Methods

Six electronic databases (PubMed, Cochrane, SCI, CNKI, VIP, and Wanfang) were searched from January 1, 2007, to March 1, 2017. Experimental or observational studies that enrolled people with nonpsychotic dementia or abnormal insulin levels in which insulin levels or MMSE scores (events in nonpsychotic dementia) were the outcome measures. Random-effects models were chosen for this meta-analysis. Sample size, mean, s.d., and events were primarily used to generate effect sizes (with the PRIMA registration number CRD42017069860).

Results

50 articles met the final inclusion criteria. Insulin levels in cerebrospinal fluid were lower (Hedges' g = 1.196, 95% CI = 0.238 to 2.514, and P = 0.014), while the levels in peripheral blood were higher in nonpsychotic dementia patients (Hedges' g = 0.853 and 95% CI = 0.579 to 1.127), and MMSE scores were significantly lower in the high insulin group than in the healthy control group (Hedges' g = 0.334, 95% CI = 0.249 to 0.419, and P = 0.000).

Conclusions

Our comprehensive results indicate that blood insulin levels may increase in patients with nonpsychotic dementia.

Biomarkers for cognitive decline in patients with diabetes mellitus: evidence from clinical studies

Diabetes mellitus is considered as an important factor for cognitive decline and dementia in recent years. However, cognitive impairment in diabetic patients is often underestimated and kept undiagnosed, leading to thousands of diabetic patients suffering from worsening memory. Available reviews in this field were limited and not comprehensive enough. Thus, the present review aimed to summarize all available clinical studies on diabetic patients with cognitive decline, and to find valuable biomarkers that might be applied as diagnostic and therapeutic targets of cognitive impairment in diabetes. The biomarkers or risk factors of cognitive decline in diabetic patients could be classified into the following three aspects: serum molecules or relevant complications, functional or metabolic changes by neuroimaging tools, and genetic variants. Specifically, factors related to poor glucose metabolism, insulin resistance, inflammation, comorbid depression, micro-/macrovascular complications, adipokines, neurotrophic molecules and Tau protein presented significant changes in diabetic patients with cognitive decline. Besides, neuroimaging platform could provide more clues on the structural, functional and metabolic changes during the cognitive decline progression of diabetic patients. Genetic factors related to cognitive decline showed inconsistency based on the limited studies. Future studies might apply above biomarkers as diagnostic and treatment targets in a large population, and regulation of these parameters might shed light on a more valuable, sensitive and specific strategy for the diagnosis and treatment of cognitive decline in diabetic patients.

Female sex, early-onset hypertension, and risk of dementia

OBJECTIVE

To evaluate the association of early-adulthood and mid-adulthood hypertension with dementia in men and women.

METHODS

We evaluated 5,646 members of a diverse integrated health care delivery system who had clinical examinations and health survey data from 1964 to 1973 (mean age 32.7 years; early adulthood) and 1978-1985 (mean age 44.3 years; mid-adulthood) and were members as of January 1, 1996 (mean age 59.8 years). Hypertension categories based on measurements of blood pressure (BP) and change in hypertension categories between the 2 examinations (e.g., onset hypertension) were used to predict dementia incidence from January 1, 1996, to September 30, 2015. Cox proportional hazard models were adjusted for demographics, vascular comorbidities, and hypertension treatment; inverse probability weighting accounted for differential attrition between first BP measurement and start of follow-up.

RESULTS

A total of 532 individuals (9.4%) were diagnosed with dementia. Early adulthood hypertension was not associated with dementia, though effect estimates were elevated among women. Mid-adulthood hypertension was associated with 65% (95% confidence interval [CI] 1.25-2.18) increased dementia risk among women but not men. Onset of hypertension in mid-adulthood predicted 73% higher dementia risk in women (95% CI 1.24-2.40) compared to stable normotensive. There was no evidence that hypertension or changes in hypertension increased dementia risk among men.

CONCLUSIONS

Though midlife hypertension was more common in men, it was only associated with dementia risk in women. Sex differences in the timing of dementia risk factors have important implications for brain health and hypertension management.

Association Between Birth in a High Stroke Mortality State, Race, and Risk of Dementia

Importance

Birth in a group of predominantly southern US states is robustly linked to increased stroke risk. Given the role of cerebrovascular disease in dementia risk, geographic patterning may also occur for dementia incidence.

Objective

To determine whether birth in 9 high stroke mortality states (HSMSs) is associated with dementia in a diverse cohort of individuals living in Northern California.

Design, Setting, and Participants

An observational cohort study included 7423 members of Kaiser Permanente Northern California (KPNC), an integrated health care delivery system, with health survey and clinical examination data available. Data were collected between 1964 and 1973 when the individuals were middle-aged and 1996 and 2015 when participants were in later life.

Exposures

Self-reported state of birth in an HSMS (top quintile of states for stroke mortality).

Main Outcomes and Measures

Dementia diagnoses obtained from electronic health records from January 1, 1996, to October 15, 2015. Place of birth, race, educational level, and midlife vascular risk factors data were collected between 1964 and 1973.

Results

Of the 7423 persons included in the analysis, 4049 (54.5%) were women; 1354 (18.2%) were black. The mean (SD) age of study participants at their first visit between 1963 and 1974 was 42.94 (1.73) years and mean (SD) age at the beginning of follow-up for dementia in 1996 was 71.14 (2.72) years. Dementia was diagnosed in 2254 (30.4%) of the participants and was more common among those born in an HSMS than those born outside of one (455 [39.0%] vs 1799 [28.8%]). Birth in an HSMS was 9.6 times more common for black participants (795 [58.7%]) than nonblack participants (371 [6.1%]). Overall, birth in an HSMS was associated with a 28% higher risk of dementia (adjusted hazard ratio [aHR], 1.28; 95% CI, 1.13-1.46) adjusted for age, sex, and race. Compared with nonblack persons born outside of an HSMS, black individuals born in an HSMS had the highest dementia risk (aHR, 1.67; 95% CI, 1.48-1.88), followed by black individuals not born in an HSMS (aHR, 1.48; 95% CI, 1.28-1.72), and nonblack persons born in an HSMS had a 46% increased risk (aHR, 1.46; 95% CI, 1.23-1.74). Cumulative 20-year dementia risks at age 65 years were 30.13% (95% CI, 26.87%-32.93%) and 21.80% (95% CI, 20.51%-22.91%) for individuals born in and outside an HSMS, respectively.

Conclusions and Relevance

To our knowledge, this is the first study to date of place of birth and incident dementia and shows increased risk for individuals born in an HSMS, even though all participants subsequently resided in California. Birth in an HSMS was common among black participants. Place of birth has enduring consequences for dementia risk and may be a major contributor to racial disparities in dementia.