Low pulmonary function (PF) is associated with poor cognitive function and dementia. There are few studies of change in PF in mid-life and late-life cognitive status.
Design and Participants
We studied this is 3,665 subjects from AGES-Reykjavik Study who had at least one measure of forced expiratory volume/ 1 sec (FEV1) and were cognitively tested on average 23 years later. A subset of 1,281 subjects had two or three measures of FEV1 acquired over a 7.8 year period. PF was estimated as FEV1/Height2. Rate of PF decline was estimated as the slope of decline over time. Cognitive status was measured with continuous scores of memory, speed of processing, and executive function, and as the dichotomous outcomes of mild cognitive impairment (MCI) and dementia.
Lower PF measured in mid-life predicted lower memory, speed of processing, executive function, and higher likelihood of MCI and dementia 23 years later. Decrease of PF over a 7.8-year period in mid-life was not associated with lower cognitive function or dementia.
Reduced PF measured in mid-life may be an early marker of later cognitive problems. Additional studies characterizing early and late PF changes are needed.
Cognition; Dementia; Forced Expiratory Volume; Longitudinal Cohort Studies
Beta-amyloid (Aβ), a vasoactive protein, and elevated blood pressure (BP) levels are associated with Alzheimer’s disease (AD) and possibly vascular dementia (VaD). We investigated the joint association of mid-life BP and Aβ peptide levels with the risk for late-life AD and VaD. Subjects were 667 Japanese-American men (including 73 with a brain autopsy), from the prospective Honolulu Heart Program/Honolulu Asia Aging Study (1965 – 2000). Mid-life BP was measured starting in 1971 participants mean age 58 years, Aβ was measured in specimens collected1980/82, and assessment of dementia and autopsy collection started in 1991/93. The outcome measures were prevalent (present in 1991/3) and incident AD (n= 53, including 38 with no contributing cardiovascular disease), and VaD (n=24). Cerebral amyloid angiopathy (CAA), β-amyloid neuritic plaques, and neurofibrillary tangles were evaluated in post-mortem tissue. The risk for AD significantly increased with lower levels of plasma Aβ (Aβ1-40 hazard ratio (HR) 2.1, 95% confidence interval (CI) 1.4 – 3.1; Aβ1-42 HR 1.6, 95% CI 1.1 – 2.3). Evidence of interaction between diastolic BP and plasma Aβ (1-40 pinteraction <0.05; 1-42 pinteraction <0.07) levels, indicated the Aβ-related risk for AD was higher when BP was higher. Low plasma Aβ was associated with the presence of CAA (ptrend<0.05), but not the other neuropathologies. Aβ plasma levels start decreasing at least 15 years before AD is diagnosed, and the association of Aβ to AD is modulated by mid-life diastolic BP. Elevated BP may compromise vascular integrity leading to CAA and impaired Aβ clearance from the brain.
Amyloid; blood pressure; brain; aging; dementia
The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal Mendelian Long QT Syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals we identified 35 common variant QT interval loci, that collectively explain ∼8-10% of QT variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 novel QT loci in 298 unrelated LQTS probands identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode for proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies novel candidate genes for ventricular arrhythmias, LQTS,and SCD.
genome-wide association study; QT interval; Long QT Syndrome; sudden cardiac death; myocardial repolarization; arrhythmias
Knowledge of adipose composition in relation to mortality may help delineate inconsistent relationships between obesity and mortality in old age. We evaluated relationships between abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) density, mortality, biomarkers, and characteristics.
VAT and SAT density were determined from computed tomography scans in persons aged 65 and older, Health ABC (n = 2,735) and AGES-Reykjavik (n = 5,131), and 24 nonhuman primates (NHPs). Associations between adipose density and mortality (4–13 years follow-up) were assessed with Cox proportional hazards models. In NHPs, adipose density was related to serum markers and tissue characteristics.
Higher density adipose tissue was associated with mortality in both studies with adjustment for risk factors including adipose area, total fat, and body mass index. In women, hazard ratio and 95% CI for the densest quintile (Q5) versus least dense (Q1) for VAT density were 1.95 (1.36–2.80; Health ABC) and 1.88 (1.31–2.69; AGES-Reykjavik) and for SAT density, 1.76 (1.35–2.28; Health ABC) and 1.56 (1.15–2.11; AGES-Reykjavik). In men, VAT density was associated with mortality in Health ABC, 1.52 (1.12–2.08), whereas SAT density was associated with mortality in both Health ABC, 1.58 (1.21–2.07), and AGES-Reykjavik, 1.43 (1.07–1.91). Higher density adipose tissue was associated with smaller adipocytes in NHPs. There were no consistent associations with inflammation in any group. Higher density adipose tissue was associated with lower serum leptin in Health ABC and NHPs, lower leptin mRNA expression in NHPs, and higher serum adiponectin in Health ABC and NHPs.
VAT and SAT density provide a unique marker of mortality risk that does not appear to be inflammation related.
Obesity; Aging; Leptin; Adiponectin.
Objective: to examine the relationships between impairments in hearing and vision and mortality from all-causes and cardiovascular disease (CVD) among older people.
Design: population-based cohort study.
Participants: the study population included 4,926 Icelandic individuals, aged ≥67 years, 43.4% male, who completed vision and hearing examinations between 2002 and 2006 in the Age, Gene/Environment Susceptibility-Reykjavik Study (AGES-RS) and were followed prospectively for mortality through 2009.
Methods: participants were classified as having ‘moderate or greater’ degree of impairment for vision only (VI), hearing only (HI), and both vision and hearing (dual sensory impairment, DSI). Cox proportional hazard regression, with age as the time scale, was used to calculate hazard ratios (HR) associated with impairment and mortality due to all-causes and specifically CVD after a median follow-up of 5.3 years.
Results: the prevalence of HI, VI and DSI were 25.4, 9.2 and 7.0%, respectively. After adjusting for age, significantly (P < 0.01) increased mortality from all causes, and CVD was observed for HI and DSI, especially among men. After further adjustment for established mortality risk factors, people with HI remained at higher risk for CVD mortality [HR: 1.70 (1.27–2.27)], whereas people with DSI remained at higher risk of all-cause mortality [HR: 1.43 (1.11–1.85)] and CVD mortality [HR: 1.78 (1.18–2.69)]. Mortality rates were significantly higher in men with HI and DSI and were elevated, although not significantly, among women with HI.
Conclusions: older men with HI or DSI had a greater risk of dying from any cause and particularly cardiovascular causes within a median 5-year follow-up. Women with hearing impairment had a non-significantly elevated risk. Vision impairment alone was not associated with increased mortality.
AGES-Reykjavik study; hearing; vision; dual sensory impairment; all-cause mortality; cardiovascular disease mortality; older people
Forced vital capacity (FVC), a spirometric measure of pulmonary function, reflects lung volume and is used to diagnose and monitor lung diseases. We performed genome-wide association study meta-analysis of FVC in 52,253 individuals from 26 studies and followed up the top associations in 32,917 additional individuals of European ancestry. We found six new regions associated at genome-wide significance (P < 5 × 10−8) with FVC in or near EFEMP1, BMP6, MIR-129-2/HSD17B12, PRDM11, WWOX, and KCNJ2. Two (GSTCD and PTCH1) loci previously associated with spirometric measures were related to FVC. Newly implicated regions were followed-up in samples of African American, Korean, Chinese, and Hispanic individuals. We detected transcripts for all six newly implicated genes in human lung tissue. The new loci may inform mechanisms involved in lung development and pathogenesis of restrictive lung disease.
Atrophy of medial temporal lobe (MTL) and basal ganglia (BG) are characteristic of various neurodegenerative diseases in older people. In search of potentially modifiable factors that lead to atrophy in these structures, we studied the association of vascular risk factors to atrophy of MTL and BG in 368 non-demented men and women [b. 1907–1935] who participated in the Age, Gene/Environment, Susceptibility - Reykjavik Study. A fully automated segmentation pipeline estimated volumes of MTL and BG from whole brain MRI performed at baseline and 2.4 years later. Linear regression models showed higher systolic and diastolic blood pressures and the presence of Apo E ε4 were independently associated with increased atrophy of MTL but no association of vascular risk factors with atrophy of BG. The different susceptibility of MTL and BG atrophy to the presence of vascular risk factors suggests the relatively preserved perfusion of BG when vascular risk factors are present.
Medial temporal lobe; hippocampus; basal ganglia; thalamus; atrophy; aging; vascular risk factors
There are few studies on the long-term associations of physical activity (PA) to cognition. Here, we examine the association of midlife PA to late-life cognitive function and dementia.
The sample consisted of a population-based cohort of men and women (born in 1907–1935) participating in the Age Gene/Environment Susceptibility—Reykjavik Study. The interval between the midlife ascertainment of PA and late-life cognitive function was 26 years. Composite scores of speed of processing, memory, and executive function were assessed with a battery of neuropsychological tests, and dementia was diagnosed according to international guidelines. There were 4,761 nondemented participants and 184 (3.7%) with a diagnosis of dementia, with complete data for the analysis.
Among the participants, no midlife PA was reported by 68.8%, ≤5 hours PA by 26.5%, and >5 hours PA by 4.5%. Excluding participants with dementia compared with the no PA group, both PA groups had significantly faster speed of processing (≤5 hours, β = .22; >5 hours, β = .32, p trend < .0001), better memory (≤5 hours, β = .15; >5 hours, β = .18, p trend < .0001), and executive function (≤5 hours, β = .09; >5 hours, β = .18, p trend< .0001), after controlling for demographic and cardiovascular factors. The ≤5 hours PA group was significantly less likely to have dementia in late life (odds ratio: 0.6, 95% confidence interval: 0.40–0.88) after adjusting for confounders.
Midlife PA may contribute to maintenance of cognitive function and may reduce or delay the risk of late-life dementia.
Physical activity; Cognitive function; Longitudinal study
Thyroid dysfunction is associated with cognitive impairment and dementia, including Alzheimer disease (AD). It remains unclear whether thyroid dysfunction results from, or contributes to, Alzheimer pathology. We determined whether thyroid function is associated with dementia, specifically AD, and Alzheimer-type neuropathology in a prospective population-based cohort of Japanese-American men. Thyrotropin, total and free thyroxine were available in 665 men aged 71–93 years and dementia-free at baseline (1991), including 143 men who participated in an autopsy sub-study. During a mean follow-up of 4.7 (SD: 1.8) years, 106 men developed dementia of whom 74 had AD. Higher total and free thyroxine levels were associated with an increased risk of dementia and AD (age and sex adjusted hazard ratio (95% confidence interval) per SD increase in free thyroxine: 1.21 (1.04; 1.40) and 1.31 (1.14; 1.51) respectively). In the autopsied sub-sample, higher total thyroxine was associated with higher number of neocortical neuritic plaques and neurofibrillary tangles. No associations were found for thyrotropin. Our findings suggest that higher thyroxine levels are present with Alzheimer clinical disease and neuropathology.
Epidemiology; thyroid hormones; thyrotropin; total thyroxine; free thyroxine; dementia; Alzheimer disease; neuropathology; neuritic plaques; neurofibrillary tangles
To examine whether lifetime DSM-IV diagnosis of major depressive disorder (MDD), including age at onset and number of episodes, is associated with brain atrophy in older persons without dementia.
Within the population-based AGES-Reykjavik Study 4,354 persons (mean age 76±5 years, 58% women) without dementia had a 1.5Tesla brain MRI. Automated brain segmentation total and regional brain volumes were calculated. History of MDD, including age at onset and number of episodes, and MDD in the past 2 weeks was diagnosed according to DSM-IV criteria using the MINI International Neuropsychiatric Interview.
Of the total sample, 4.5% reported a lifetime history of MDD; 1.5% had a current diagnosis of MDD (including 75% with a prior history of depression) and 3.0% had a past but no current diagnosis (remission). After adjusting for multiple covariates, compared to participants never depressed, those with current MDD (irrespective of past) had more global brain atrophy (B=−1.25%; 95%CI −2.05 to −0.44%), including more gray and white matter atrophy in most lobes as well as more atrophy of the hippocampus and thalamus. Participants with current, first onset, MDD also had more brain atrophy (B=−1.62%; 95%CI −3.30 to 0.05%), while those remitted did not (B=0.06%; 95%CI −0.54 to 0.66%).
In older persons without dementia, current MDD, irrespective of prior history, but not remitted MDD, was associated with widespread gray and white matter brain atrophy. Prospective studies should examine whether MDD is a consequence of or contributes to brain volume loss and development of dementia.
To examine the association between plasma concentrations of antioxidative micronutrients and leukocyte telomere length (LTL) in elderly adults.
Cross-sectional cohort study.
Austrian Stroke Prevention Study, a population-based cohort study on brain aging.
Individuals with a mean age of 66 ± 7 (n = 786; 58% female).
Concentrations of vitamin C, lutein, zeaxanthin, β-cryptoxanthin, canthaxanthin, lycopene, α- and γ-tocopherol, α- and β-carotene, and retinol in plasma, advanced oxidation protein products as a measure of oxidative stress in serum, and LTL were measured. Vitamins and carotenoids were measured using high-performance liquid chromatography, advanced oxidation protein products using spectrophotometry, and telomere length using quantitative real-time polymerase chain reaction.
Multiple linear regression analyses with adjustment for age and sex demonstrated that higher lutein, zeaxanthin, and vitamin C concentrations were strongly associated with longer telomere length. The associations were independent of body mass index, maximum oxygen uptake, and vascular risk factors and were not mediated by advanced oxidation protein products content.
This study provides first evidence that higher lutein, zeaxanthin, and vitamin C concentrations in plasma are associated with longer LTL in normal elderly persons and suggest a protective role of these vitamins in telomere maintenance.
telomere length; vitamin C; lutein zeaxanthin; aging; antioxidants; oxidative stress
The C677T variant in the methylenetetrahydrofolate reductase (MTHFR; EC 220.127.116.11) enzyme, a key player in the folate metabolic pathway, has been associated with increased risk of migraine with aura. Other genes encoding molecular components of this pathway include Methionine synthase (MTR; EC 18.104.22.168), and Methionine synthase reductase (MTRR; EC 22.214.171.124) among others. We performed a haplotype analysis of migraine risk and MTHFR, MTR, and MTRR.
Study participants are from a random sub-sample participating in the population-based AGES-Reykjavik Study, including subjects with non-migraine headache (n=367), migraine without aura (n=85), migraine with aura (n=167), and no headache (n=1347). Haplotypes spanning each gene were constructed using Haploview. Association testing was performed on single SNPs and haplotypes using logistic regression, controlling for demographic and cardiovascular risk factors and correcting for multiple testing
Haplotype analysis suggested an association between MTRR haplotypes and reduced risk of migraine with aura. All other associations were not significant after correcting for multiple testing.
These results suggest that MTRR variants may protect against migraine with aura in an older population.
Migraine; folate; haplotype; genetics
Mobility limitations are common and hazardous in community-dwelling older adults but are largely understudied, particularly regarding the role of the central nervous system (CNS). This has limited development of clearly defined pathophysiology, clinical terminology, and effective treatments. Understanding how changes in the CNS contribute to mobility limitations has the potential to inform future intervention studies.
A conference series was launched at the 2012 conference of the Gerontological Society of America in collaboration with the National Institute on Aging and the University of Pittsburgh. The overarching goal of the conference series is to facilitate the translation of research results into interventions that improve mobility for older adults.
Evidence from basic, clinical, and epidemiological studies supports the CNS as an important contributor to mobility limitations in older adults without overt neurologic disease. Three main goals for future work that emerged were as follows: (a) develop models of mobility limitations in older adults that differentiate aging from disease-related processes and that fully integrate CNS with musculoskeletal contributors; (b) quantify the contribution of the CNS to mobility loss in older adults in the absence of overt neurologic diseases; (c) promote cross-disciplinary collaboration to generate new ideas and address current methodological issues and barriers, including real-world mobility measures and life-course approaches.
In addition to greater cross-disciplinary research, there is a need for new approaches to training clinicians and investigators, which integrate concepts and methodologies from individual disciplines, focus on emerging methodologies, and prepare investigators to assess complex, multisystem associations.
Motor control; Central nervous system; Mobility.
Cardiovascular risk factors in middle-age are associated with cognitive impairment and dementia in older age. Less is known about the burden of calcified subclinical atherosclerosis and cognition, especially in midlife. We examined the association of coronary artery and abdominal aortic calcified plaque (CAC and AAC, respectively) with cognitive functioning in middle-aged adults.
This cross-sectional study included 2,510 black and white adults (age: 43–55 years) without heart disease or stroke who completed a year 25 follow-up exam (2010–11) as part of the Coronary Artery Risk Development in Young Adults Study. CAC and AAC were measured with non-contrast computed tomography. Cognition was assessed with the Digit Symbol Substitution Test (DSST) (psychomotor speed), Stroop Test (executive function), and Rey Auditory Verbal Learning Test (RAVLT) (verbal memory).
A greater amount of CAC and AAC was associated with worse performance on each test of cognitive function after adjustment for age, sex, race, education, and study center. Associations were attenuated, but remained significant for the DSST and RAVLT following additional adjustment for vascular risk factors, including adiposity, smoking, alcohol use, dyslipidemia, hypertension, and diabetes. Compared to participants without CAC or AAC, those with both CAC and AAC, but not CAC or AAC alone was associated with lower DSST scores (p<0.05).
In this community-based sample, greater subclinical atherosclerotic calcification was associated with worse psychomotor speed and memory in midlife. These findings underscore the importance of a life course approach to the study of cognitive impairment with aging.
atherosclerosis; heart disease; calcium score; cognition; subclinical disease; risk factors
Abnormal interaction of β-amyloid 42 (Aβ42) with copper, zinc and iron induce peptide aggregation and oxidation in Alzheimer's disease (AD). However, in health, Aβ degradation is mediated by extracellular metalloproteinases, neprilysin, insulin degrading enzyme (IDE) and matrix metalloproteinases. We investigated the relationship between levels of Aβ and biological metals in CSF. We assayed CSF copper, zinc, other metals and Aβ42 in ventricular autopsy samples of Japanese American men (N= 131) from the population-based Honolulu–Asia Aging Study. There was a significant inverse correlation of CSF Aβ42 with copper, zinc, iron, manganese and chromium. The association was particularly strong in the subgroup with high levels of both zinc and copper. Selenium and aluminum levels were not associated to CSF Aβ42. In vitro, the degradation of synthetic Aβ substrate added to CSF was markedly accelerated by low levels (2 μM) of exogenous zinc and copper. While excessive interaction with copper and zinc may induce neocortical Aβ precipitation in AD, soluble Aβ degradation is normally promoted by physiological copper and zinc concentrations.
amyloid; Alzheimer's disease; metalloproteinase; cerebrospinal fluid; zinc; copper; iron; manganese; chromium
Depression has been identified as a risk factor for dementia among patients with Type 2 diabetes mellitus but the cognitive domains and patient groups most affected have not been identified.
To determine whether comorbid depression in patients with type 2 diabetes accelerates cognitive decline.
A 40-month cohort study of participants in the ACCORD-MIND trial
52 clinics organized into 6 clinical networks across the US and Canada.
2977 participants with Type 2 diabetes at high-risk for cardiovascular events
Main Outcome Measures
The Digit Symbol Substitution Test (DSST), Rey Auditory Verbal Learning Test (RAVLT), and the modified Stroop test were used to assess cognition. The Physician’s Health Questionnaire-9 (PHQ-9) was used to assess depression. Mixed effects statistical models were used to analyze these cognitive outcomes incorporating depression as a time-dependent covariate.
Participants with scores indicative of depression (PHQ-9 > 10) showed greater cognitive decline during 40-months follow-up on all tests, with the following differences in estimated least squares means: DSST 0.72 (95%CI 0.25, 1.19, p=0.0029), RAVLT 0.18 (95%CI 0.07, 0.29, p=0.0009), Stroop Interference −1.06 (95%CI −1.93, −0.18, p=0.0179). This effect of depression on risk of cognitive decline did not differ according to: previous cardiovascular disease, baseline cognition or age, intensive vs. standard treatment of glucose, blood pressure treatment, lipid treatment, or insulin use. Addition of demographic and clinical covariates to models did not significantly change the cognitive decline associated with depression.
Depression in patients with Type 2 diabetes was associated with greater cognitive decline in all domains, across all treatment arms, and in all participant subgroups assessed.
To investigate whether the severity and location of cerebral white matter hyperintensities (WMHs) and brain infarcts are correlated with the signs of retinal microvascular abnormalities in the elderly.
The study included 4176 men and women (mean age, 76 years) who participated in the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study. Digital retinal images of both dilated eyes were taken and evaluated for the presence of retinal focal arteriolar signs (focal arteriolar narrowing and arteriovenous nicking) and retinopathy lesions (retinal blot hemorrhages and microaneurysms). Brain MRI scans were acquired and evaluated for the presence and distribution of cerebral infarcts and WMHs. Logistic and multinomial logistic models were constructed to estimate the association of retinal microvascular signs to brain lesions.
Controlling for demographic and major cardiovascular risk factors, retinal focal arteriolar signs, but not retinopathy lesions, were significantly associated with an increasing load of subcortical and periventricular WMHs. The strongest association was found between retinal arteriolar signs and a heavier WMH load, specifically in subcortical frontal lobe and periventricular frontal and parietal caps. There was a tendency towards bilateral retinal focal arteriolar narrowing being more strongly associated with the heavier load of subcortical WMHs. Arteriovenous nicking was significantly associated with subcortical infarcts.
In older adults, retinal focal arteriolar signs, but not retinopathy lesions, are correlated with the load of diffuse WMHs, particularly those located in the subcortical frontal lobe and the periventricular frontal and parietal caps of the brain.
To examine the long-term association between mid-life physical activity (PA) and lower extremity function (LEF) in late-life.
A longitudinal study with an average of 25 years of follow up.
A large community-based population of 4753 men and women (mean age 76±6 yrs) residing in Reykjavik, Iceland.
On the basis of weekly hours of regular PA reported at the mid-life examination, participants were classified as “Active” and “Inactive”. Measures of LEF in late-life included gait speed from 6m walk (meter per second, m/s), Timed Up and Go (TUG, second), and Knee Extension (KE) strength (kg) tests. Linear regression analysis was used to examine the association.
Participants who were active in mid-life had significantly better LEF (faster gait speed,, β = 0.05, p ≤ 0.001; faster TUG time, β = −0.53, p ≤ 0.001; stronger KE strength, β = 1.3, p ≤ 0.001) in late-life compared with those who were not active in mid-life, after adjusting for socio-demographic and cardiovascular risk factors. After adjustment for cognitive function in late life (speed of processing, memory, and executive function), participants who were active in mid-life still had significantly faster gait speed (β = 0.04, p ≤ 0.001), faster TUG time (β = −0.34, p ≤ 0.001), and greater KE strength (β = 0.87, p ≤ 0.001) in old age compared with those who were not active in mid-life.
Regular PA reported in mid-life is associated with better performance of LEF in later life, even after controlling for late life cognitive function.
mid-life physical activity; mobility; aging; cognitive function; lower extremity function
Genome-wide association studies (GWAS) have revealed 74 single nucleotide polymorphisms (SNPs) associated with high-density lipoprotein cholesterol (HDL) blood levels. This study is, to our knowledge, the first genome-wide interaction study (GWIS) to identify SNP×SNP interactions associated with HDL levels. We performed a GWIS in the Rotterdam Study (RS) cohort I (RS-I) using the GLIDE tool which leverages the massively parallel computing power of Graphics Processing Units (GPUs) to perform linear regression on all genome-wide pairs of SNPs. By performing a meta-analysis together with Rotterdam Study cohorts II and III (RS-II and RS-III), we were able to filter 181 interaction terms with a p-value<1 · 10−8 that replicated in the two independent cohorts. We were not able to replicate any of these interaction term in the AGES, ARIC, CHS, ERF, FHS and NFBC-66 cohorts (Ntotal = 30,011) when adjusting for multiple testing. Our GWIS resulted in the consistent finding of a possible interaction between rs774801 in ARMC8 (ENSG00000114098) and rs12442098 in SPATA8 (ENSG00000185594) being associated with HDL levels. However, p-values do not reach the preset Bonferroni correction of the p-values. Our study suggest that even for highly genetically determined traits such as HDL the sample sizes needed to detect SNP×SNP interactions are large and the 2-step filtering approaches do not yield a solution. Here we present our analysis plan and our reservations concerning GWIS.
To determine the associations between classes of antihypertensive medication use and the risk of cognitive impairment among elderly hypertensive men.
The Honolulu-Asia Aging Study is a prospective, community-based cohort study of Japanese American men conducted in Honolulu, Hawaii. We examined 2,197 participants (mean age 77 years at cohort entry, 1991–1993, followed through September 2010) with hypertension and without dementia or cognitive impairment at baseline, who provided information on medication use. Cognitive function was assessed at 7 standardized examinations using the Cognitive Abilities Screening Instrument (CASI). Cognitive impairment was defined as a CASI score <74.
A total of 854 men developed cognitive impairment (median follow-up, 5.8 years). β-Blocker use as the sole antihypertensive drug at baseline was consistently associated with a lower risk of cognitive impairment (incidence rate ratio [IRR] 0.69; 95% confidence interval [CI] 0.50–0.94), as compared with men not taking any antihypertensive medications, adjusting for multiple potential confounders. The use of diuretics, calcium channel blockers, angiotensin-converting enzyme inhibitors, or vasodilators alone was not significantly associated with cognitive impairment. Results were similar excluding those with cardiovascular disease or <1 year of follow-up, and additionally adjusting for pulse pressure, heart rate, baseline and midlife systolic blood pressure, and midlife antihypertensive treatment (IRR 0.65; 95% CI 0.45–0.94). The association between β-blocker use and cognitive impairment was stronger among men with diabetes, men aged >75 years, and those with pulse pressure ≥70 mm Hg.
β-blocker use is associated with a lower risk of developing cognitive impairment in elderly Japanese American men.
To investigate the independent effects of antihypertensive treatment and blood pressure (BP) levels on physical and mental health status in patients with arterial disease.
Cross-sectional analyses within the Secondary Manifestations of ARTerial disease (SMART) study, a single centre cohort study.
5,877 patients (mean age 57) with symptomatic and asymptomatic arterial disease who underwent a standardized vascular screening.
Main outcome measure
Self-rated physical and mental health assessed with the Short Form (SF)-36.
In the total population, antihypertensive drug use and increased intensity of antihypertensive treatment was associated with poorer health status independent of important confounders including BP levels; adjusted mean differences (95%CI) in physical and mental health between 0 and ≥3 antihypertensives were -1.2 (-2.1, -0.3) and -3.5 (-4.4; -2.6). Furthermore, lower systolic and lower diastolic BP levels were related to poorer physical and mental health status independently of antihypertensive treatment. Mean differences (95%CI) in physical and mental health status per SD decrease in systolic BP were -0.56 (-0.84; -0.27) and -0.32 (-0.61; -0.03), and per SD decrease in diastolic BP -0.50 (-0.78; -0.23) and -0.08 (-0.36; 0.20). The association between low BP and poor health status was particularly present in patients with coronary artery disease.
In a population of patients with asymptomatic and symptomatic arterial disease, antihypertensive treatment and lower BP levels are independently associated with poorer self-rated physical and mental health. These results might indicate that there are different underlying mechanisms explaining these independent associations.
antihypertensive treatment; blood pressure; physical health; mental health; cardiovascular disease
To examine the relationship of cognitive performance to exposure to insulin (INS) and thiazolidinediones (TZD) in the ACCORD-MIND cohort.
Participants (55-80 yrs) with type 2 diabetes (T2D), hemoglobin A1c (HbA1c) >7.5% (>58 mmol/mol), and a high risk of cardiovascular events were randomly assigned to receive intensive control targeting HbA1c to < 6.0% (42 mmol/mol) or a standard strategy targeting HbA1c to 7.0-7.9% (53-63 mmol/mol). The Digit Symbol Substitution Test (DSST) was assessed at baseline and at 20 and 40 mo. Exposure to INS was calculated as average daily dose/kg of body weight; exposure to rosiglitazone (ROS) was calculated as days of ROS prescription in the intervals preceding the 20 and 40-mo DSSTs.
At baseline, INS use was associated with reduced DSST performance, but not after controlling for co-morbidities and lab values. There was no relationship between use of a TZD and DSST performance on at baseline. ROS but not INS exposure was associated with greater decline in DSST performance over 40 mo in subjects randomized to the intensive but not the standard group.
Exposure to a TZD may increase cognitive decline in some patients with T2D. However, these results may be confounded by unexplained differences between participants.
thiazolidinediones; insulin; diabetes; cognition
Unrecognized myocardial infarction (MI) is prognostically important but electrocardiography (ECG), the main epidemiology tool for detection, is insensitive to MI.
Determine prevalence and mortality risk for unrecognized MI (UMI) detected by cardiac magnetic resonance (CMR) or ECG.
ICELAND MI is a cohort substudy of the Age, Gene/Environment Susceptibility-Reykjavik Study (enrollment January 2004–January 2007) using ECG or CMR to detect UMI.
Community dwelling participants in Iceland over age 67.
936 participants (ages 67–93 years) including 670 who were randomly selected and 266 with diabetes.
Main Outcome Measures
MI prevalence and mortality through September 1, 2011. Results reported with 95% confidence limits and net reclassification improvement (NRI).
Of 936 participants, 91 had recognized MI (RMI; 9.7% CI 8–12%), and 157 had UMI by CMR (17%; CI 14–19%) which was more prevalent than the 46 UMI by ECG (5%; CI 4–6%, p<0.001). Diabetic participants had more UMI by CMR than UMI by ECG (n=72; 21%; CI 17–26% vs. n=15; 4%; CI 2–7%, p<0.001). UMI by CMR was associated with atherosclerosis risk factors, coronary calcium, coronary revascularization, and peripheral vascular disease. Over a median of 6.4 years, 33% (CI 23–43%) of individuals with RMI died (30 of 91) and 28% (CI 21–35%) with UMI died (44 of 157), both higher rates than the 17% (CI 15–20%) with no MI that died (119 of 688). UMI by CMR improved risk stratification for mortality over RMI (NRI: 0.34; CI 0.16–0.53). Adjusting for age, sex, diabetes, and RMI, UMI by CMR remained associated with mortality (HR 1.45 CI 1.02–2.06, absolute risk increase (ARI) 8%) and significantly improved risk stratification for mortality, NRI 0.16 (CI 0.01–0.31)) but UMI by ECG did not (HR 0.88, CI 0.45–1.73 ARI −2%; NRI: −0.05; CI −0.17–0.05). Compared to those with RMI, participants with UMI by CMR used cardiac medications such as statins less often (36%; CI, 28–43% or 56/157 vs.73%; CI 63–82% or 66/91; p<0.001).
In a community-based cohort, the prevalence of UMI by CMR was higher than the prevalence of recognized MI or UMI by ECG, and was associated with increased mortality risk.
Genome-wide association studies (GWAS) have identified numerous loci influencing cross-sectional lung function, but less is known about genes influencing longitudinal change in lung function.
We performed GWAS of the rate of change in forced expiratory volume in the first second (FEV1) in 14 longitudinal, population-based cohort studies comprising 27,249 adults of European ancestry using linear mixed effects model and combined cohort-specific results using fixed effect meta-analysis to identify novel genetic loci associated with longitudinal change in lung function. Gene expression analyses were subsequently performed for identified genetic loci. As a secondary aim, we estimated the mean rate of decline in FEV1 by smoking pattern, irrespective of genotypes, across these 14 studies using meta-analysis.
The overall meta-analysis produced suggestive evidence for association at the novel IL16/STARD5/TMC3 locus on chromosome 15 (P = 5.71 × 10-7). In addition, meta-analysis using the five cohorts with ≥3 FEV1 measurements per participant identified the novel ME3 locus on chromosome 11 (P = 2.18 × 10-8) at genome-wide significance. Neither locus was associated with FEV1 decline in two additional cohort studies. We confirmed gene expression of IL16, STARD5, and ME3 in multiple lung tissues. Publicly available microarray data confirmed differential expression of all three genes in lung samples from COPD patients compared with controls. Irrespective of genotypes, the combined estimate for FEV1 decline was 26.9, 29.2 and 35.7 mL/year in never, former, and persistent smokers, respectively.
In this large-scale GWAS, we identified two novel genetic loci in association with the rate of change in FEV1 that harbor candidate genes with biologically plausible functional links to lung function.