Cumulative Use of Proton Pump Inhibitors and Risk of Dementia: The Atherosclerosis Risk in Communities Study

BACKGROUND AND OBJECTIVES

Studies on the association between proton pump inhibitor (PPI) use and dementia report mixed results and do not examine the impact of cumulative PPI use. We evaluated the associations between current and cumulative PPI use and risk of incident dementia in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

These analyses used participants from a community-based cohort (ARIC) from the time of enrollment (1987-1989) through 2017. PPI use was assessed through visual medication inventory at clinic visits 1 (1987-1989) to 5 (2011-2013) and reported annually in study phone calls (2006-2011). This study uses ARIC visit 5 as baseline because this was the first visit in which PPI use was common. PPI use was examined 2 ways: current use at visit 5 and duration of use before visit 5 (from visit 1 to 2011, exposure categories: 0 day, 1 day-2.8 years, 2.8-4.4 years, >4.4 years). The outcome was incident dementia after visit 5. Cox proportional hazard models were used, adjusted for demographics, comorbid conditions, and other medication use.

RESULTS

A total of 5,712 dementia-free participants at visit 5 (mean age 75.4 ± 5.1 years; 22% Black race; 58% female) were included in our analysis. The median follow-up was 5.5 years. The minimum cumulative PPI use was 112 days, and the maximum use was 20.3 years. There were 585 cases of incident dementia identified during follow-up. Participants using PPIs at visit 5 were not at a significantly higher risk of developing dementia during subsequent follow-up than those not using PPIs (hazard ratio (HR): 1.1 [95% confidence interval (CI) 0.9-1.3]). Those who used PPIs for >4.4 cumulative years before visit 5 were at 33% higher risk of developing dementia during follow-up (HR: 1.3 [95% CI 1.0-1.8]) than those reporting no use. Associations were not significant for lesser durations of PPI use.

DISCUSSION

Future studies are needed to understand possible pathways between cumulative PPI use and the development of dementia.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that the use of prescribed PPIs for >4.4 years by individuals aged 45 years and older is associated with a higher incidence of newly diagnosed dementia.

Association of Plasma Aβ42/Aβ40 Ratio and Late-Onset Epilepsy: Results From the Atherosclerosis Risk in Communities Study

BACKGROUND AND OBJECTIVES

The objective of this study was to determine the relationship between plasma β-amyloid (Aβ), specifically the ratio of 2 Aβ peptides (the Aβ42/Aβ40 ratio, which correlates with increased accumulation of Aβ in the CNS), and late-onset epilepsy (LOE).

METHODS

We used Medicare fee-for-service claims codes from 1991 to 2018 to identify cases of LOE among 1,424 Black and White men and women enrolled in the Atherosclerosis Risk in Communities (ARIC) study cohort. The Aβ42/Aβ40 ratio was calculated from plasma samples collected from ARIC participants in 1993-1995 (age 50-71 years) and 2011-2013 (age 67-90 years). We used survival analysis accounting for the competing risk of death to determine the relationship between late-life plasma Aβ42/Aβ40, and its change from midlife to late life, and the subsequent development of epilepsy. We adjusted for demographics, the apolipoprotein e4 genotype, and comorbidities, including stroke, dementia, and head injury. A low plasma ratio of 2 Aβ peptides, the Aβ42/Aβ40 ratio, correlates with low CSF Aβ42/Aβ40 and with increased accumulation of Aβ in the CNS.

RESULTS

Decrease in plasma Aβ42/Aβ40 ratio from midlife to late life, but not an isolated measurement of Aβ42/Aβ40, was associated with development of epilepsy in later life. For every 50% reduction in Aβ42/Aβ40, there was a 2-fold increase in risk of epilepsy (adjusted subhazard ratio 2.30, 95% CI 1.27-4.17).

DISCUSSION

A reduction in plasma Aβ42/Aβ40 is associated with an increased risk of subsequent epilepsy. Our observations provide a further validation of the link between Aβ, hyperexcitable states, and LOE.

The effect of missing data and imputation on the detection of bias in cognitive testing using differential item functioning methods

Background

Item response theory (IRT) methods for addressing differential item functioning (DIF) can detect group differences in responses to individual items (e.g., bias). IRT and DIF-detection methods have been used increasingly often to identify bias in cognitive test performance by characteristics (DIF grouping variables) such as hearing impairment, race, and educational attainment. Previous analyses have not considered the effect of missing data on inferences, although levels of missing cognitive data can be substantial in epidemiologic studies.

Methods

We used data from Visit 6 (2016–2017) of the Atherosclerosis Risk in Communities Neurocognitive Study (N = 3,580) to explicate the effect of artificially imposed missing data patterns and imputation on DIF detection.

Results

When missing data was imposed among individuals in a specific DIF group but was unrelated to cognitive test performance, there was no systematic error. However, when missing data was related to cognitive test performance and DIF group membership, there was systematic error in DIF detection. Given this missing data pattern, the median DIF detection error associated with 10%, 30%, and 50% missingness was -0.03, -0.08, and -0.14 standard deviation (SD) units without imputation, but this decreased to -0.02, -0.04, and -0.08 SD units with multiple imputation.

Conclusions

Incorrect inferences in DIF testing have downstream consequences for the use of cognitive tests in research. It is therefore crucial to consider the effect and reasons behind missing data when evaluating bias in cognitive testing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01572-2.

Assessing Bias in Cognitive Testing for Older Adults with Sensory Impairment: An Analysis of Differential Item Functioning in the Baltimore Longitudinal Study on Aging (BLSA) and the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS)

OBJECTIVES

Vision and hearing impairments affect 55% of people aged 60+ years and are associated with lower cognitive test performance; however, tests rely on vision, hearing, or both. We hypothesized that scores on tests that depend on vision or hearing are different among those with vision or hearing impairments, respectively, controlling for underlying cognition.

METHODS

Leveraging cross-sectional data from the Baltimore Longitudinal Study of Aging (BLSA) and the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS), we used item response theory to test for differential item functioning (DIF) by vision impairment (better eye presenting visual acuity worse than 20/40) and hearing impairment (better ear .5-4 kHz pure-tone average > 25 decibels).

RESULTS

We identified DIF by vision impairment for tests whose administrations do not rely on vision [e.g., Delayed Word Recall both in ARIC-NCS: .50 logit difference between impaired and unimpaired (p = .04) and in BLSA: .62 logits (p = .02)] and DIF by hearing impairment for tests whose administrations do not rely on hearing [Digit Symbol Substitution test in BLSA: 1.25 logits (p = .001) and Incidental Learning test in ARIC-NCS: .35 logits (p = .001)]. However, no individuals had differences between unadjusted and DIF-adjusted measures of greater than the standard error of measurement.

CONCLUSIONS

DIF by sensory impairment in cognitive tests was independent of administration characteristics, which could indicate that elevated cognitive load among persons with sensory impairment plays a larger role in test performance than previously acknowledged. While these results were unexpected, neither of these samples are nationally representative and each has unique selection factors; thus, replication is critical.

Plasma phospholipid very-long-chain SFAs in midlife and 20-year cognitive change in the Atherosclerosis Risk in Communities (ARIC): a cohort study

BACKGROUND

Very-long-chain SFAs (VLSFAs) have recently gained considerable attention as having beneficial effects on health and aging.

OBJECTIVES

The objective of this study was to assess the associations of plasma phospholipid VLSFAs [arachidic acid (20:0), behenic acid (22:0), tricosanoic acid (23:0), and lignoceric acid (24:0)] with 20-y cognitive decline in the Atherosclerosis Risk in Communities (ARIC) participants. Furthermore, this study compared the associations of plasma phospholipid VLSFAs with 5 common groups of fatty acids [i.e., total SFAs, total MUFAs, total ω-3 (n-3) PUFAs, total marine-derived ω-3 PUFAs, total ω-6 PUFAs].

METHODS

This study used a cohort study design of 3229 ARIC participants enrolled at the Minnesota field center. Fatty acids were measured at visit 1 (1987-1989); and cognition was assessed at visits 2 (1990-1992), 4 (1996-1998), and 5 (2011-2013) using 3 tests: the Delayed Word Recall Test (DWRT), the Digit-Symbol Substitution Test (DSST), and the Word Fluency Test (WFT).

RESULTS

Higher proportions of plasma phospholipid total VLSFAs and each individual VLSFA were associated with less decline in WFT, a test of verbal fluency. For example, 1 SD higher in total VLSFAs at baseline was associated with 0.057 SD (95% CI: 0.018, 0.096, P = 0.004) less cognitive decline over 20 y as measured by WFT score. None of the 5 common fatty acid groups were associated with change in WFT, but a higher proportion of plasma phospholipid total MUFAs was associated with greater decline in DWRT; higher total ω-6 PUFAs with less decline in DWRT; and higher total ω-3 and total marine-derived ω-3 PUFAs with less decline in DSST.

CONCLUSIONS

This study suggests that higher proportions of plasma phospholipid VLSFAs in midlife may be associated with less 20-y cognitive decline.

Metabolomics and cognition in African American adults in midlife: the atherosclerosis risk in communities study

Clinical studies have shown alterations in metabolic profiles when patients with mild cognitive impairment and Alzheimer's disease dementia were compared to cognitively normal subjects. Associations between 204 serum metabolites measured at baseline (1987-1989) and cognitive change were investigated in 1035 middle-aged community-dwelling African American participants in the biracial Atherosclerosis Risk in Communities (ARIC) Study. Cognition was evaluated using the Delayed Word Recall Test (DWRT; verbal memory), the Digit Symbol Substitution Test (DSST; processing speed) and the Word Fluency Test (WFT; verbal fluency) at visits 2 (1990-1992) and 4 (1996-1998). In addition, Cox regression was used to analyze the metabolites as predictors of incident hospitalized dementia between baseline and 2011. There were 141 cases among 1534 participants over a median 17.1-year follow-up period. After adjustment for established risk factors, one standard deviation increase in N-acetyl-1-methylhistidine was significantly associated with greater 6-year change in DWRT scores (β=-0.66 words; P=3.65 × 10-4). Two metabolites (one unnamed and a long-chain omega-6 polyunsaturated fatty acid found in vegetable oils (docosapentaenoate (DPA, 22:5 n-6)) were significantly associated with less decline on the DSST (DPA: β=1.25 digit-symbol pairs, P=9.47 × 10-5). Two unnamed compounds and three sex steroid hormones were associated with an increased risk of dementia (all P<3.9 × 10-4). The association of 4-androstene-3beta, 17beta-diol disulfate 1 with dementia was replicated in European Americans. These results demonstrate that screening the metabolome in midlife can detect biologically plausible biomarkers that may improve risk stratification for cognitive impairment at older ages.

Factors Related to Differences in Retention among African American and White Participants in the Atherosclerosis Risk in Communities Study (ARIC) Prospective Cohort: 1987-2013

BACKGROUND

Few studies have addressed retention of minorities, particularly African Americans, in longitudinal research. Our aim was to determine whether there was differential retention between African Americans and Whites in the ARIC cohort and identify cardiovascular disease (CVD) risk factors and indicators of socioeconomic status (SES) associated with these retention differences.

METHODS

15,688 participants, 27% African American and 73% White, were included from baseline, 1987-1989, and classified as having died, lost or withdrew from study contact, or remained active in study calls through 2013. Life tables were created illustrating retention patterns stratified by race, from baseline through visit 5, 2011-2013. Prevalence tables stratified by race, participation status, and center were created to examine CVD risk factors and SES at baseline and visit 5.

RESULTS

54% of African Americans compared with 62% of Whites were still in follow-up by 2013. This difference was due to an 8% higher cumulative incidence of death among African Americans. Those who remained in follow-up had the lowest baseline CVD risk factors and better SES, followed by those who were lost/withdrew, then those who died. Whites had lower levels of most CVD risk factors and higher SES than African Americans overall at baseline and visit 5; though, the magnitude of visit 5 differences was less.

CONCLUSIONS

In the ARIC cohort, retention differed among African Americans and Whites, but related more to mortality differences than dropping-out. Additional research is needed to better characterize the factors contributing to minority participants' recruitment and retention in longitudinal research.

GWAS for executive function and processing speed suggests involvement of the CADM2 gene

To identify common variants contributing to normal variation in two specific domains of cognitive functioning, we conducted a genome-wide association study (GWAS) of executive functioning and information processing speed in non-demented older adults from the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) consortium. Neuropsychological testing was available for 5429-32,070 subjects of European ancestry aged 45 years or older, free of dementia and clinical stroke at the time of cognitive testing from 20 cohorts in the discovery phase. We analyzed performance on the Trail Making Test parts A and B, the Letter Digit Substitution Test (LDST), the Digit Symbol Substitution Task (DSST), semantic and phonemic fluency tests, and the Stroop Color and Word Test. Replication was sought in 1311-21860 subjects from 20 independent cohorts. A significant association was observed in the discovery cohorts for the single-nucleotide polymorphism (SNP) rs17518584 (discovery P-value=3.12 × 10(-8)) and in the joint discovery and replication meta-analysis (P-value=3.28 × 10(-9) after adjustment for age, gender and education) in an intron of the gene cell adhesion molecule 2 (CADM2) for performance on the LDST/DSST. Rs17518584 is located about 170 kb upstream of the transcription start site of the major transcript for the CADM2 gene, but is within an intron of a variant transcript that includes an alternative first exon. The variant is associated with expression of CADM2 in the cingulate cortex (P-value=4 × 10(-4)). The protein encoded by CADM2 is involved in glutamate signaling (P-value=7.22 × 10(-15)), gamma-aminobutyric acid (GABA) transport (P-value=1.36 × 10(-11)) and neuron cell-cell adhesion (P-value=1.48 × 10(-13)). Our findings suggest that genetic variation in the CADM2 gene is associated with individual differences in information processing speed.

Vitamin D, vitamin D binding protein gene polymorphisms, race and risk of incident stroke: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND PURPOSE

Low vitamin D levels, measured by serum 25-hydroxyvitamin D [25(OH)D], are associated with increased stroke risk. Less is known about whether this association differs by race or D binding protein (DBP) single nucleotide polymorphism (SNP) status. Our objective was to characterize the associations of and interactions between 25(OH)D levels and DBP SNPs with incident stroke. It was hypothesized that associations of low 25(OH)D with stroke risk would be stronger amongst persons with genotypes associated with higher DBP levels.

METHODS

25(OH)D was measured by mass spectroscopy in 12 158 participants in the Atherosclerosis Risk in Communities (ARIC) study (baseline 1990-1992, mean age 57 years, 57% female, 23% black) and they were followed through 2011 for adjudicated stroke events. Two DBP SNPs (rs7041, rs4588) were genotyped. Cox models were adjusted for demographic/behavioral/socioeconomic factors.

RESULTS

During a median of 20 years follow-up, 804 incident strokes occurred. The lowest quintile of 25(OH)D (<17.2 ng/ml) was associated with higher stroke risk [hazard ratio (HR) 1.34 (1.06-1.71) versus highest quintile]; this association was similar by race (P interaction 0.60). There was weak evidence of increased risk of stroke amongst those with 25(OH)D < 17.2 ng/ml and either rs7041 TG/GG [HR = 1.29 (1.00-1.67)] versus TT genotype [HR = 1.19 (0.94-1.52)] (P interaction 0.28) or rs4588 CA/AA [HR = 1.37 (1.07-1.74)] versus CC genotype [HR = 1.14 (0.91-1.41)] (P interaction 0.11).

CONCLUSIONS

Low 25(OH)D is a risk factor for stroke. Persons with low 25(OH)D who are genetically predisposed to high DBP (rs7041 G, rs4588 A alleles), who therefore have lower predicted bioavailable 25(OH)D, may be at greater risk for stroke, although our results were not conclusive and should be interpreted as hypothesis generating.

Genetic contributions to variation in general cognitive function: a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53949)

General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health- and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N=53,949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P=3.93 × 10(-9), MIR2113; rs17522122, P=2.55 × 10(-8), AKAP6; rs10119, P=5.67 × 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P=1 × 10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N=6617) and the Health and Retirement Study (N=5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e.=5%) and 28% (s.e.=7%), respectively. Using polygenic prediction analysis, ~1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N=5487; P=1.5 × 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.

Vitamin D and cognitive function and dementia risk in a biracial cohort: the ARIC Brain MRI Study

BACKGROUND AND PURPOSE

Some recent studies in older, largely white populations suggest that vitamin D, measured by 25-hydroxyvitamin D [25(OH)D], is important for cognition, but such results may be affected by reverse causation. Measuring 25(OH)D in late middle age before poor cognition affects behavior may provide clearer results.

METHODS

This was a prospective cohort analysis of 1652 participants (52% white, 48% black) in the Atherosclerosis Risk in Communities (ARIC) Brain MRI Study. 25(OH)D was measured from serum collected in 1993-1995. Cognition was measured by the delayed word recall test (DWRT), the digit symbol substitution test (DSST) and the word fluency test (WFT). Dementia hospitalization was defined by ICD-9 codes. Adjusted linear, logistic and Cox proportional hazards models were used.

RESULTS

Mean age of participants was 62 years and 60% were female. Mean 25(OH)D was higher in whites than blacks (25.5 vs. 17.3 ng/ml, P < 0.001). Lower 25(OH)D was not associated with lower baseline scores or with greater DWRT, DSST or WFT decline over a median of 3 or 10 years of follow-up (P > 0.05). Over a median of 16.6 years, there were 145 incident hospitalized dementia cases. Although not statistically significant, lower levels of 25(OH)D were suggestive of an association with increased dementia risk [hazard ratio for lowest versus highest race-specific tertile: whites 1.32 (95% confidence interval 0.69, 2.55); blacks 1.53 (95% confidence interval 0.84, 2.79)].

CONCLUSIONS

In contrast to prior studies performed in older white populations, our study of late middle age white and black participants did not find significant associations between lower levels of 25(OH)D with lower cognitive test scores at baseline, change in scores over time or dementia risk.

Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer's disease

Eleven susceptibility loci for late-onset Alzheimer's disease (LOAD) were identified by previous studies; however, a large portion of the genetic risk for this disease remains unexplained. We conducted a large, two-stage meta-analysis of genome-wide association studies (GWAS) in individuals of European ancestry. In stage 1, we used genotyped and imputed data (7,055,881 SNPs) to perform meta-analysis on 4 previously published GWAS data sets consisting of 17,008 Alzheimer's disease cases and 37,154 controls. In stage 2, 11,632 SNPs were genotyped and tested for association in an independent set of 8,572 Alzheimer's disease cases and 11,312 controls. In addition to the APOE locus (encoding apolipoprotein E), 19 loci reached genome-wide significance (P < 5 × 10(-8)) in the combined stage 1 and stage 2 analysis, of which 11 are newly associated with Alzheimer's disease.

Cognitive decline and oral health in middle-aged adults in the ARIC study

Even before dementia becomes apparent, cognitive decline may contribute to deterioration in oral health. This cohort study of middle-aged adults evaluated associations of six-year change in cognitive function with oral health behaviors and conditions in the Atherosclerosis Risk in Communities (ARIC) study. Cognitive function was measured at study visits in 1990-1992 and 1996-1998 with three tests: (a) Delayed Word Recall (DWR), (b) Digit Symbol Substitution (DSS), and (c) Word Fluency (WF). Cognitive decline scores were computed as 'studentized' residuals of 1996-1998 scores regressed against 1990-1992 scores. In 1996-1998, 10,050 participants answered dental screening questions, and 5,878 of 8,782 dentate participants received a comprehensive oral examination. Multiple regression models used cognitive change to predict oral health behaviors and conditions with adjustment for covariates. In the fully adjusted models, greater decline in all three measures of cognitive function was associated with increased odds of complete tooth loss. Greater decline in DSS and WF scores was associated with infrequent toothbrushing. Decline in WF scores was also associated with higher plaque levels. In these middle-aged adults, six-year cognitive decline was modestly associated with less frequent toothbrushing, plaque deposit, and greater odds of edentulism, but not with other oral behaviors or diseases.

Do systolic BP and pulse pressure relate to ventricular enlargement?

BACKGROUND AND PURPOSE

To evaluate the association between systolic, diastolic and pulse pressure, and increase in ventricular size (VS). Observations in laboratory animals suggest intraventricular pulse pressure (systolic-diastolic) may play a role in ventricular enlargement.

METHODS

Initial magnetic resonance (MR) scans and vascular risk factors evaluation were performed in 1812 Atherosclerosis Risk in Communities participants in 1994-1995. In 2004-2006, 1130 participants underwent repeat MR. VS was rated using a validated nine-point scale. Multiple logistic regression analysis assessed association between blood pressure measures and pulse pressure, and the change between the MR scans of VS controlling for age, sex and race.

RESULTS

At baseline 1112 participants (385 black women, 200 black men, 304 white women and 223 white men) had a mean age of 61.7 ± 4.3 years. In adjusted models pulse pressure at baseline was associated with an increase in VS [odds ratio (OR) 1.19, 95% confidence interval (CI) 1.01-1.40], as was systolic pressure (OR 1.28, 95% CI 1.03-1.58).

CONCLUSIONS

Systolic pressure and pulse pressure are associated with future development of increased VS. The findings are consistent with the animal literature that increased pulse pressure predisposes to risk of future increased VS. High pulse pressure might play a role in the pathogenesis of normal pressure hydrocephalus.

Risk factors for lacune subtypes in the Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

Lacunar infarctions are mainly due to 2 microvascular pathologies: lipohyalinosis and microatheroma. Little is known about risk factor differences for these subtypes. We hypothesized that diabetes and glycated hemoglobin (HbA(1)c) would be related preferentially to the lipohyalinotic subtype.

METHODS

We performed a cross-section analysis of the brain MRI data from 1,827 participants in the Atherosclerosis Risk in Communities study. We divided subcortical lesions ≤ 20 mm in diameter into those ≤ 7 mm (of probable lipohyalinotic etiology) and 8-20 mm (probably due to microatheroma) and used Poisson regression to investigate associations with the number of each type of lesion. Unlike previous studies, we also fitted a model involving lesions <3 mm.

RESULTS

Age (prevalence ratio [PR] 1.11 per year; 95% confidence interval [CI] 1.08-1.14), black ethnicity (vs white, PR 1.66; 95% CI 1.27-2.16), hypertension (PR 2.12; 95% CI 1.61-2.79), diabetes (PR 1.42; 95% CI 1.08-1.87), and ever-smoking (PR 1.34; 95% CI 1.04-1.74) were significantly associated with lesions ≤ 7 mm. Findings were similar for lesions <3 mm. HbA(1)c, substituted for diabetes, was also associated with smaller lesions. Significantly associated with 8-20 mm lesions were age (PR 1.14; 95% CI 1.09-1.20), hypertension (PR 1.79; 95% CI 1.14-2.83), ever-smoking (PR 2.66; 95% CI 1.63-4.34), and low-density lipoprotein (LDL) cholesterol (PR 1.27 per SD; 95% CI 1.06-1.52). When we analyzed only participants with lesions, history of smoking (PR 1.99; 95% CI 1.23-3.20) and LDL (PR 1.33 per SD; 95% CI 1.08-1.65) were associated with lesions 8-20 mm.

CONCLUSIONS

Smaller lacunes (even those <3 mm) were associated with diabetes and HbA(1)c, and larger lacunes associated with LDL cholesterol, differences which support long-held theories relating to their underlying pathology. The findings may contribute to broader understanding of cerebral microvascular disease.

Vascular risk factors and longitudinal changes on brain MRI: the ARIC study

OBJECTIVE

To evaluate associations between vascular risk factors and changes in burden of infarcts, ventricular size (VS), sulcal widening (SW), and white matter hyperintensities (WMH) in an initially middle-aged, biracial cohort from the Atherosclerosis Risk in Communities (ARIC) study.

METHODS

Initial brain magnetic resonance (MR) scans and evaluations for vascular risk factors were performed in 1,812 ARIC participants in 1994-1995. In 2004-2006, 1,130 ARIC participants underwent repeat MR scans. MR scans were rated using a validated 9-point scale for VS, SW, and WMH. Infarcts were recorded. Multiple logistic regression analysis was used to assess associations between vascular risk factors and change between MR scans of one or more grades in VS, SW, WMH, or appearance of new infarcts, controlling for age, sex, and race.

RESULTS

At baseline, the 1,112 participants with usable scans (385 black women, 200 black men, 304 white women, 223 white men) had a mean age of 61.7 ± 4.3 years. In adjusted models, diabetes at baseline was associated with incident infarcts (odds ratio [OR] 1.95, 95% confidence interval [CI] 1.29-2.95) and worsening SW (OR 2.10, 95% CI 1.36-3.24). Hypertension at baseline was associated with incident infarcts (OR 1.73, 95% CI 1.23-2.42). In subjects with the highest tertile of fasting blood sugar and systolic blood pressure at baseline, the risk of incident infarcts was 3.68 times higher (95% CI 1.89-7.19) than those in the lowest tertile for both.

CONCLUSION

Both atrophic and ischemic imaging changes were driven by altered glycemic and blood pressure control beginning in midlife.

Genome-wide association study of coronary heart disease and its risk factors in 8,090 African Americans: the NHLBI CARe Project

Coronary heart disease (CHD) is the leading cause of mortality in African Americans. To identify common genetic polymorphisms associated with CHD and its risk factors (LDL- and HDL-cholesterol (LDL-C and HDL-C), hypertension, smoking, and type-2 diabetes) in individuals of African ancestry, we performed a genome-wide association study (GWAS) in 8,090 African Americans from five population-based cohorts. We replicated 17 loci previously associated with CHD or its risk factors in Caucasians. For five of these regions (CHD: CDKN2A/CDKN2B; HDL-C: FADS1-3, PLTP, LPL, and ABCA1), we could leverage the distinct linkage disequilibrium (LD) patterns in African Americans to identify DNA polymorphisms more strongly associated with the phenotypes than the previously reported index SNPs found in Caucasian populations. We also developed a new approach for association testing in admixed populations that uses allelic and local ancestry variation. Using this method, we discovered several loci that would have been missed using the basic allelic and global ancestry information only. Our conclusions suggest that no major loci uniquely explain the high prevalence of CHD in African Americans. Our project has developed resources and methods that address both admixture- and SNP-association to maximize power for genetic discovery in even larger African-American consortia.

Association of lung function with cognitive decline and dementia: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Previous studies reported a higher risk of cognitive decline and dementia amongst individuals with impaired lung function. However, many did not adjust for important confounders or did not include women and non-whites.

METHODS

We studied 10,975 men and women aged 47-70 years (23% African-Americans) enrolled in the Atherosclerosis Risk in Communities Study. Pulmonary function tests and a cognitive assessment, including the Delayed Word Recall, the Digit Symbol Substitution, and the World Fluency Tests, were carried out in 1990-1992. Repeated cognitive assessments were performed in 1996-1998 for the entire cohort, and in 1993-1995, and 2004-2006 in 904 eligible individuals. Dementia hospitalization was ascertained through 2005.

RESULTS

In analysis adjusted for lifestyles, APOE genotype, and cardiovascular risk factors, impaired lung function was associated with worse cognitive function at baseline. No association was found between lung function and cognitive decline over time. Impaired lung function at baseline was associated with higher risk of dementia hospitalization during follow-up, particularly amongst younger individuals. The hazard ratios (95% confidence intervals) of dementia hospitalization were 1.6 (0.9, 2.8) and 2.1 (1.2, 3.7) comparing the lowest with the highest quartile of forced expiratory volume in 1 s and forced vital capacity, respectively. Presence of a restrictive ventilatory pattern, but not of an obstructive pattern, was associated with reduced cognitive scores and higher dementia risk.

CONCLUSION

Reduced lung function was associated with worse performance in cognitive assessments and with an increased risk of dementia hospitalization. Future research should determine whether maintaining optimal pulmonary health might prevent cognitive impairment and dementia.

Association between SLC2A9 transporter gene variants and uric acid phenotypes in African American and white families

OBJECTIVES

SLC2A9 gene variants associate with serum uric acid in white populations, but little is known about African American populations. Since SLC2A9 is a transporter, gene variants may be expected to associate more closely with the fractional excretion of urate, a measure of renal tubular transport, than with serum uric acid, which is influenced by production and extrarenal clearance.

METHODS

Genotypes of single nucleotide polymorphisms (SNPs) distributed across the SLC2A9 gene were obtained in the Genetic Epidemiology Network of Arteriopathy cohorts. The associations of SNPs with serum uric acid, fractional excretion of urate and urine urate-to-creatinine ratio were assessed with adjustments for age, sex, diuretic use, BMI, homocysteine and triglycerides.

RESULTS

We identified SLC2A9 gene variants that were associated with serum uric acid in 1155 African American subjects (53 SNPs) and 1132 white subjects (63 SNPs). The most statistically significant SNPs in African American subjects (rs13113918) and white subjects (rs11723439) were in the latter half of the gene and explained 2.7 and 2.8% of the variation in serum uric acid, respectively. After adjustment for this SNP in African Americans, 0.9% of the variation in serum uric acid was explained by an SNP (rs1568318) in the first half of the gene. Unexpectedly, SLC2A9 gene variants had stronger associations with serum uric acid than with fractional excretion of urate.

CONCLUSIONS

These findings support two different loci by which SLC2A9 variants affect uric acid levels in African Americans and suggest SLC2A9 variants affect serum uric acid level via renal and extrarenal clearance.

Risk of dementia hospitalisation associated with cardiovascular risk factors in midlife and older age: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Cardiovascular risk factors are associated with a higher risk of developing dementia. Studies in older populations, however, have often failed to show this relationship. We assessed the association between cardiovascular risk factors measured in midlife and risk of being hospitalised with dementia and determined whether this association was modified by age and ethnicity.

METHODS

We studied 11 151 participants in the population-based Atherosclerosis Risk in Communities cohort, aged 46-70 (23% African-Americans) in 1990-2, when participants underwent a physical exam and cognitive testing. Hospitalisations with dementia were ascertained through December 2004.

RESULTS

During follow-up, 203 cases of hospitalisation with dementia were identified. Smoking (hazard ratio (HR), 95% CI 1.7, 1.2 to 2.5), hypertension (HR, 95% CI 1.6, 1.2 to 2.2) and diabetes (HR, 95% CI 2.2, 1.6 to 3.0) were strongly associated with dementia, in Caucasians and African-Americans. These associations were stronger when risk factors were measured at a younger age than at an older age. In analyses including updated information on risk factors during follow-up, the HR of dementia in hypertensive versus non-hypertensive participants was 1.8 at age <55 years compared with 1.0 at age 70+ years. Parallel results were observed for diabetes (HR 3.4 in <55, 2.0 in >or=70), smoking (4.8 in <55, 0.5 in >or=70) and hypercholesterolaemia (HR 1.7 in <55, 0.9 in >or=70)

CONCLUSION

In this prospective study, smoking, hypertension and diabetes were strongly associated with subsequent risk of hospitalisation with dementia, particularly in middle-aged individuals. Our results emphasise the importance of early lifestyle modification and risk factor treatment to prevent dementia.

Retinal microvascular abnormalities and cognitive decline: the ARIC 14-year follow-up study

BACKGROUND

Because retinal and cerebral arterioles share similar pathologic processes, retinal microvascular changes are expected to be markers of cerebral small vessel disease (SVD). To better understand the role of SVD in cognitive function, we investigated the relationship between retinal microvascular abnormalities and longitudinal changes in cognitive function in a community-based study.

METHODS

A total of 803 participants underwent 4 cognitive assessments between 1990-1992 and 2004-2006, using the Word Fluency (WF) test, Digit Symbol Substitution (DSS), and Delayed Word Recall as well as retinal photography in 1993-1995. Covariate adjusted random effects linear models for repeated measures were used to determine the associations of cognitive change with specific retinal vascular abnormalities.

RESULTS

Individuals with retinopathy showed declines in executive function and psychomotor speed, with 1) an average decline in WF of -1.64 words per decade (95% confidence interval [CI] -3.3, -0.02) compared to no decline in those without retinopathy +0.06 (95% CI -0.6, 0.8) and 2) a higher frequency of rapid decliners on the DSS test.

CONCLUSION

Signs of retinal vascular changes, as markers of the cerebral microvasculature, are associated with declines in executive function and psychomotor speed, adding to the growing evidence for the role of microvascular disease in cognitive decline in the elderly.

African-American ethnicity is associated with higher plasma levels of D-dimer in adults with hypertension

BACKGROUND

African Americans with hypertension have higher cardiovascular morbidity and mortality than hypertensives from other ethnic groups. Plasma D-dimer, a fragment generated from fibrin during lysis of mature clot in vivo, is a predictor of adverse cardiovascular events.

OBJECTIVE

We investigated whether plasma levels of D-dimer differ between African American (AA) and non-Hispanic white (NHW) adults with hypertension.

METHODS

Participants included 933 AA (65 +/- 9 years, 72% women) and 821 NHW (61 +/- 9 years, 56% women) from the community. D-dimer was measured using an immunoturbidimetric assay. Multivariable regression analyses, stratified by gender, were performed to assess whether AA ethnicity was associated with D-dimer levels after adjustment for age, body mass index (BMI), total and high-density lipoprotein (HDL) cholesterol, systolic blood pressure, diabetes, history of smoking, medication (statin and aspirin) use, lifestyle variables (physical activity, alcohol intake, and education), estimated glomerular filtration rate (eGFR), and a marker of inflammation, C-reactive protein (CRP).

RESULTS

D-dimer levels were higher in AA men and women than in their NHW counterparts (mean +/- SD; men 256 +/- 199 vs. 190 +/- 183 ng mL(-1), P < 0.001; women, 290 +/- 233 vs. 225 +/- 195 ng mL(-1), P < 0.001). In both sexes, after adjustment for age, conventional risk factors, medication use, and lifestyle variables, AA ethnicity remained associated with higher D-dimer levels (P = 0.002 in men, P = 0.006 in women). These associations remained significant after additional adjustment for eGFR and plasma CRP (P = 0.003 in men, P < 0.0001 in women).

CONCLUSIONS

Among adults with hypertension, AA ethnicity was independently associated with higher plasma levels of D-dimer.

Cerebral MRI findings and cognitive functioning: the Atherosclerosis Risk in Communities study

OBJECTIVE

To examine the association between prevalent cerebral abnormalities identified on MRI and cognitive functioning in a predominantly middle-aged, population-based study cohort.

METHODS

Cerebral MRI was performed on 1,538 individuals (aged 55 to 72) from the Atherosclerosis Risk in Communities (ARIC) cohort, with no history of stroke or TIA, at study sites in Forsyth County, NC, and Jackson, MS. White matter hyperintensities (WMHs), ventricular size, and sulcal size were graded by trained neuroradiologists on a semiquantitative, 10-point scale. Cognitive functioning was assessed using the Delayed Word Recall Test (DWRT), Digit Symbol Substitution Test (DSST), and Word Fluency Test (WFT).

RESULTS

High ventricular grade was independently associated with significantly lower scores on the DWRT and DSST and greater risk (odds ratio [OR] 2.32, 95% confidence interval [CI] 1.51 to 3.56) of impaired scores (i.e., < or =10th percentile) on the DWRT. High sulcal grade was associated with a modest decrement in scores on the DWRT. The presence of coexisting high grade WMHs and silent infarcts was independently associated with lower scores on all cognitive tests and greater risk of impaired functioning on the DSST (OR 2.91, 95% CI: 1.23 to 6.89) and WFT (OR 2.28, 95% CI 1.03 to 5.08). The presence of two or more high-grade abnormalities was associated with increased risk of impaired functioning on all cognitive tests (DWRT: OR 2.23, 95% CI 1.40 to 3.55; DSST: OR 2.06, 95% CI 1.13 to 3.76; WFT: OR 2.07, 95% CI 1.23 to 3.49) independent of multiple covariates and silent infarcts.

CONCLUSION

Common changes in brain morphology are associated with diminished cognitive functioning in middle-aged and young-elderly individuals.

APOE genotype and cognitive decline in a middle-aged cohort

BACKGROUND

Most longitudinal studies of nondemented persons have reported greater cognitive decline among APOE epsilon4 carriers vs noncarriers. However, most studies involved elderly samples (aged 65+) and were not large enough to examine the three APOE alleles separately.

METHODS

Change in cognitive function was examined over a 6-year period using three neuropsychological tests among four APOE genotype groups (epsilon2/2 + epsilon2/3, epsilon3/3 (referent), epsilon4/2 + epsilon4/3, epsilon4/4). The population-based sample included 1,693 African Americans and 6,202 Caucasians initially ages 47 to 68.

RESULTS

There was increasingly greater cognitive decline from the epsilon2 group to the epsilon4/4 group in Caucasians for two of the three tests. The combination of APOE epsilon4 with hypercholesterolemia or diabetes showed the greatest cognitive decline. Among African Americans, only the test measuring psychomotor speed showed associations with APOE genotype.

CONCLUSIONS

APOE epsilon4 is associated with greater cognitive decline in middle-aged Caucasian individuals, with a reduced decline among epsilon2 carriers. This suggests that the processes by which APOE genotype mediates dementia risk are operative well in advance of overt dementia.

Retinal microvascular changes and MRI signs of cerebral atrophy in healthy, middle-aged people

OBJECTIVE

To examine the relation of retinal microvascular abnormalities and MRI signs of cerebral atrophy in healthy middle-aged people.

METHODS

A population-based, cross-sectional study involved 1,684 persons aged 51 to 72 years who had cerebral MRI and retinal photography in 1993 to 1995. Sulcal and ventricular size were quantified from the MRI scans and coded as grades 0 to 9, with sulcal widening (SW) and ventricular enlargement (VE) defined as grades 3 or higher. The presence or absence of retinopathy, microaneurysms, hemorrhages, and other characteristics were defined from retinal photographs using a standardized protocol. Generalized arteriolar narrowing was defined from a computer-assisted measurement of arteriolar diameters from digitized photographs.

RESULTS

Persons with retinopathy had higher sulcal (p = 0.001) and ventricular (p = 0.03) grades than persons without retinopathy. After adjusting for age, gender, race, mean arterial blood pressure, diabetes, cigarette smoking, common carotid artery intima-media thickness, and other vascular risk factors, retinopathy was significantly associated with SW (odds ratio [OR], 1.9; 95% CI, 1.2, 3.0) and VE (OR, 1.5; 95% CI, 1.0, 2.3). These associations persisted even in people without diabetes or hypertension (OR 1.9, 95% CI, 0.8, 4.4 for SW; OR 2.7, 95% CI, 1.2, 6.5 for VE). Other retinal arteriolar characteristics (arteriovenous nicking, focal and generalized arteriolar narrowing) were not related to sulcal or ventricular grade.

CONCLUSIONS

In healthy, middle-aged people, retinopathy is independently associated with sulcal and ventricular enlargement on MRI. This finding is compatible with the hypothesis that microvascular characteristics may influence the development of cerebral atrophic changes.

Alcohol consumption with age: a cross-sectional and longitudinal study of the Atherosclerosis Risk in Communities (ARIC) study, 1987-1995

Previous cross-sectional and longitudinal studies assessing the association between age and drinking are inconsistent. Evaluating 15,425 Black and White men and women from four communities, this study sought to determine whether there was a consistent relation between age and drinking in cross-sectional and longitudinal analyses and to determine change in drinking status and level of consumption (occasional, light to moderate, and heavier drinkers) at follow-up. Cross-sectional analyses of drinking were performed for Atherosclerosis Risk in Communities examinations 1 (1987-1989) and 3 (1993-1995). The changes in drinking status and level were determined for the 12,565 persons with information at both examinations. Prevalence of drinking was generally inversely associated with age in the cross-sectional analyses for all ethnic/gender groups, and drinking prevalence decreased over the 6 years of follow-up for all except Black women. Only among Black drinkers was younger age associated with a higher level of alcohol consumption in both cross-sectional and prospective analyses. Thus, whether drinking prevalence declines, the amount consumed by drinkers is decreased, or whether both factors contribute to the decrease appears to vary with ethnicity and gender. The change in drinking level was substantial with more than 40% of baseline drinkers reporting drinking cessation or a different level of consumption at follow-up.

Association of nonsteroidal anti-inflammatory drugs and aspirin with cognitive performance in middle-aged adults

OBJECTIVES

To assess the cross-sectional association of regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin with cognitive function in 13,153 individuals, aged 48-67 years, participating in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

Regular use of NSAIDs or aspirin was analyzed in relation to the results of three cognitive tests, the Delayed Word Recall Test, the WAIS-R Digit Symbol Subtest, and the Word Fluency Test.

RESULTS

After adjustment for covariates previously found to be associated with cognition in this sample, we found a weak negative association between current use of aspirin and poor Word Recall [OR = 0.84 (95% confidence interval: 0.68-1.04)] and poor Word Fluency [OR = 0.85 (0.70-1.03)]. We found no association between current use of aspirin and Digit Symbol score, nor did we find current NSAID use to be significantly associated with any of the cognitive tests.

CONCLUSIONS

This study suggests a modest association, at best, between NSAIDs or aspirin and better cognitive function.

Dietary antioxidant intake and cognitive performance in middle-aged adults. The Atherosclerosis Risk in Communities (ARIC) Study investigators

OBJECTIVE

To assess the cross-sectional association of dietary and supplemental antioxidant (carotenoids, vitamins C and E) intake with cognitive function in 12 187 individuals, aged 48-67 years, participating in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

Dietary intake of antioxidant vitamins, as assessed by a food frequency questionnaire, and use of supplements were analysed in relation to the results of three cognitive tests, the delayed word recall test, the Wechsler adult intelligence scale, revised (WAIS-R) digit symbol subtest and the word fluency test.

RESULTS

After adjustment for covariates previously found to be associated with cognition in this sample, we found no consistent associations between dietary antioxidant vitamin intake or supplement use and any of the cognitive tests.

CONCLUSIONS

This study suggests little, if any, association between antioxidant vitamin intake and better cognitive function in middle-aged adults.

Psychometric properties of the Weekly Stress Inventory (WSI): extension to a patient sample with coronary heart disease

The psychometric characteristics of the Weekly Stress Inventory (WSI) were examined in a sample of medical patients (N = 84) diagnosed with coronary heart disease. In addition to the WSI, patients completed measures assessing recent depressive symptoms, physical symptoms, Type A behavior, and trait anxiety. Patients also monitored stress for 3 weeks (n = 46), completing the Daily Stress Inventory (a measure of minor stress) daily and the WSI at concurrent 1-week intervals. Results indicated that the WSI is an internally consistent and moderately stable measure. Validity of the WSI was supported by (a) strong correlations with a concurrently administered measure of minor stress (concurrent validity); (b) significant positive correlations with measures assessing recent depressive symptoms, physical symptoms, and Type A behavior; and (c) a lack of relationship with a measure of trait anxiety (discriminant validity).

Stress, coping, and well-being among third-year medical students

BACKGROUND

Medical school is recognized as a stressful environment that often exerts a negative effect on the academic performance, physical health, and psychological well-being of the student.

METHOD

Stress, coping, depression, and somatic distress were examined among 69 third-year students completing a psychiatry clerkship in 1992-93 at the University of Mississippi School of Medicine. Stress was assessed using the Medical Education Hassles Scale-R. Coping was assessed using the Coping Strategies Inventory. Depression was assessed using the Center for Epidemiologic Studies-Depression Scale, and somatic distress was assessed using the Wahler Physical Symptoms Inventory. Statistical methods included correlational analysis and hierarchical regression.

RESULTS

Clinical levels of depression were found in 16 (23%) of the students, and 39 (57%) endorsed high levels of somatic distress. Stress accounted for a large percentage of the distress variance (i.e., 29% to 50%). Coping efforts contributed significant variance to the prediction of distress above and beyond that accounted for by stress alone, especially in relation to depression. Coping efforts classified by Engagement strategies were associated with fever depressive symptoms, while coping efforts classified by Disengagement strategies were associated with higher levels of depressive symptoms.

CONCLUSIONS

Because students who employed coping efforts characterized by Engagement strategies suffered from fewer depressive symptoms, the results suggest that training in these types of strategies may be a useful intervention to lessen the negative consequences of stress among medical students.

Contingent social reinforcement for fluid compliance in a hemodialysis patient

Two approaches, (a) patient education and (b) compliance-contingent social reinforcement, were employed to improve compliance with fluid restrictions in a chronically noncompliant hemodialysis patient of borderline intellectual functioning. Results indicated that only social reinforcement led to improved compliance (i.e., decreased intersession weight gain). Treatment effects were well maintained at both 3- and 6-month follow-ups. Contingency management strategies are recommended as a potentially cost effective treatment for noncompliance in hemodialysis patients.

The relationship of ovarian steroids, headache activity and menstrual distress: a pilot study with female migraineurs

Fourteen female volunteers who met diagnostic criteria for migraine headache monitored their headache activity and menstrual distress symptoms for one menstrual cycle. Serum estradiol and progesterone levels, and menstrual distress measures were collected at four points of the menstrual cycle: menstrual, ovulatory, luteal and premenstrual. Results indicated that one patient (7.1%) had menstrual migraine, 10 patients (71.4%) had menstrually-related headache and 3 (21.4%) had migraine headache unrelated to their menstrual cycle: subsequent analyses were conducted with the first two groups. Headache activity for the sample was highest during the premenstrual phase. Headache activity during the luteal and premenstrual phases was related to luteal phase progesterone levels. Menstrual distress was highest during the menstrual and premenstrual phases of the cycle, and these symptoms were related to higher estradiol levels, higher estradiol/progesterone ratios, and increased headache activity. These results indicated that for women with menstrual migraine or menstrually-related migraine, luteal progesterone and estradiol and the estradiol/progesterone ratio may be significantly related to menstrual distress during the premenstrual phase of the cycle. The estradiol/progesterone ratio was not more related to headache or menstrual distress than either of these ovarian hormones alone. Suggestions for future research in this area are offered.

Efficacy of behavioral management and patient education on vascular access cleansing compliance in hemodialysis patients

Compared four treatment conditions to test their ability to enhance compliance with vascular access cleansing (VAC) procedures in a group of 56 hemodialysis patients. The conditions were patient education, behavioral management with monetary incentive, patient education/behavioral management, and attention control. Behavioral observers rated VAC behavior at pretreatment, posttreatment 1-month follow-up, and 1-year follow-up. Knowledge of VAC procedures was also assessed via a questionnaire at pretreatment and posttreatment. Data were analyzed using repeated-measures multivariate analyses of variance. Results indicated that the patients in the education/behavioral, behavioral, and education groups gave significantly more correct answers on our VAC knowledge questionnaires at posttreatment than did patients in the attention control group. Further, patients in the education/behavioral and behavioral groups completed significantly more VAC steps at posttreatment and 1-month follow-up than did patients in the education group and in the attention control group. Differences were not maintained at 1-year follow-up, although more than 50% of the patients were lost to follow-up. Implications of the present findings for behavioral and educational interventions are discussed.