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1.  Dietary Fats, Cholesterol and Iron as Risk Factors for Parkinson's Disease 
Epidemiologic findings suggest that dietary components may contribute to the etiology of Parkinson's disease (PD). This population-based case-control study evaluated PD risk and dietary intake of fats, cholesterol and iron.
Newly diagnosed case (n = 420) and age/gender/ethnicity-matched unrelated controls (n = 560) were identified between 1992 and 2006 from the Group Health Cooperative health maintenance organization in western Washington State, and the University of Washington neurology clinic. In-person interviews elicited data on food frequency habits during most of adult life. Nutritional intakes were calculated and analyzed, with adjustments made for total energy intake (the ‘nutrition density’ technique).
Cholesterol intake in the highest quartile compared with the lowest quartile was associated with a decreased risk of PD in men (odds ratio (OR)=0.53, 95% CI: 0.33, 0.86). The highest versus the lowest quartile of dietary iron increased PD risk in men (OR=1.82, 95% CI: 1.11, 2.99). When the lowest quartile of cholesterol and the highest quartile for iron were compared to the highest quartile of cholesterol and the lowest quartile of iron, no association was seen in women, but for men PD risk was increased (OR=2.70, 95% CI: 1.26, 5.76). Saturated fat intake below the median in combination with iron intake above the median also increased PD risk (OR=1.50, 95% CI: 1.07, 2.11) in both genders combined.
A low intake of cholesterol, particularly in the presence of high iron, may be associated with an increased risk for PD.
PMCID: PMC2751763  PMID: 18424169
2.  Gene Variants Associated With Ischemic Stroke 
Background and Purpose
The purpose of this study was to determine whether 74 single nucleotide polymorphisms (SNPs), which had been associated with coronary heart disease, are associated with incident ischemic stroke.
Based on antecedent studies of coronary heart disease, we prespecified the risk allele for each of the 74 SNPs. We used Cox proportional hazards models that adjusted for traditional risk factors to estimate the associations of these SNPs with incident ischemic stroke during 14 years of follow-up in a population-based study of older adults: the Cardiovascular Health Study (CHS).
In white CHS participants, the prespecified risk alleles of 7 of the 74 SNPs (in HPS1, ITGAE, ABCG2, MYH15, FSTL4, CALM1, and BAT2) were nominally associated with increased risk of stroke (one-sided P<0.05, false discovery rate=0.42). In black participants, the prespecified risk alleles of 5 SNPs (in KRT4, LY6G5B, EDG1, DMXL2, and ABCG2) were nominally associated with stroke (one-sided P<0.05, false discovery rate=0.55). The Val12Met SNP in ABCG2 was associated with stroke in both white (hazard ratio, 1.46; 90% CI, 1.05 to 2.03) and black (hazard ratio, 3.59; 90% CI, 1.11 to 11.6) participants of CHS. Kaplan-Meier estimates of the 10-year cumulative incidence of stroke were greater among Val allele homozygotes than among Met allele carriers in both white (10% versus 6%) and black (12% versus 3%) participants of CHS.
The Val12Met SNP in ABCG2 (encoding a transporter of sterols and xenobiotics) was associated with incident ischemic stroke in white and black participants of CHS.
PMCID: PMC2881155  PMID: 19023099
brain infarction; cerebrovascular accident; epidemiology; genetics; prevention; risk factors
3.  LINE-1 DNA Methylation, Smoking and Risk of Parkinson’s Disease 
Journal of Parkinson's disease  2012;2(4):303-308.
Long interspersed nucleotide element-1 (LINE-1) retrotransposons are located throughout the human genome. Those retaining an intact 5′ promoter can copy and insert themselves into the DNA of neural progenitor cells that express tyrosine hydroxylase, which may influence differentiation and survival of these cells. Because LINE-1 promoter methylation is associated with decreased LINE-1 propagation, we compared LINE-1 methylation profiles in blood mononuclear cells between 292 newly diagnosed Parkinson’s disease (PD) cases and 401 unrelated, neurologically normal controls. Overall, PD was not associated with percent methylation of the LINE-1 promoter. However, the predictable inverse association between PD and ever smoking tobacco was strongest for men and women with the lowest LINE-1 promoter methylation, and less apparent as LINE-1 methylation increased. Underlying this possible interaction, ever regularly smoking tobacco was associated with decreased LINE-1 methylation in controls (age- and sex-adjusted linear regression β = −0.24, 95% confidence interval [CI] −0.43, −0.04), but not in cases (β = 0.06, 95% CI −0.17, 0.28, interaction p = 0.06). PD cases may have innate differences in their ability to respond to tobacco smoke.
PMCID: PMC3962286  PMID: 23938260
4.  Occupational Factors and Risk of Parkinson’s Disease: A Population-Based Case–Control Study 
Parkinson’s disease (PD) has been associated with various workplace factors, but the evidence is inconsistent.
To estimate the risk of PD associated with various jobs and workplace exposures.
We conducted a population-based, case–control study of 404 incident PD cases and 526 age and sex-matched controls, collecting self-reported work histories including job titles and exposures to various industrial toxicants. Relative risks of PD from these exposures were estimated with odds ratios (OR) and 95% confidence intervals (CI) using logistic regression.
Risk was not significantly affected by farming work, by metal work, or by exposure to pesticides, metals, or solvents.
These findings do not provide support for the hypothesis that workplace factors affect the risk of PD.
PMCID: PMC3299410  PMID: 20025075
risk factors in epidemiology; Parkinson’s disease/parkinsonism; toxicology; occupational; human
5.  Early diagnosis and treatment of obstructive sleep apnea after stroke 
Neurology: Clinical Practice  2013;3(3):192-201.
Sleep-disordered breathing is an increasingly recognized disorder that is particularly prevalent among stroke patients. Obstructive sleep apnea, a form of sleep-disordered breathing, is associated with multiple major stroke risk factors but is also an independent risk factor for stroke. In addition, untreated sleep apnea is associated with poor functional outcome after stroke. Sleep apnea is amenable to treatment and should be considered a modifiable stroke risk factor, though long-term compliance remains a major barrier. A better understanding of the relationship between sleep apnea and stroke may prompt providers to pursue the early diagnosis and treatment of underlying sleep-disordered breathing to both improve the chance of recovery from stroke in the short term and to reduce the risk of recurrent stroke in the long term.
PMCID: PMC3721244  PMID: 23914326
6.  Neighborhood socioeconomic disadvantage and mortality after stroke 
Neurology  2013;80(6):520-527.
Residence in a socioeconomically disadvantaged community is associated with mortality, but the mechanisms are not well understood. We examined whether socioeconomic features of the residential neighborhood contribute to poststroke mortality and whether neighborhood influences are mediated by traditional behavioral and biologic risk factors.
We used data from the Cardiovascular Health Study, a multicenter, population-based, longitudinal study of adults ≥65 years. Residential neighborhood disadvantage was measured using neighborhood socioeconomic status (NSES), a composite of 6 census tract variables representing income, education, employment, and wealth. Multilevel Cox proportional hazard models were constructed to determine the association of NSES to mortality after an incident stroke, adjusted for sociodemographic characteristics, stroke type, and behavioral and biologic risk factors.
Among the 3,834 participants with no prior stroke at baseline, 806 had a stroke over a mean 11.5 years of follow-up, with 168 (20%) deaths 30 days after stroke and 276 (34%) deaths at 1 year. In models adjusted for demographic characteristics, stroke type, and behavioral and biologic risk factors, mortality hazard 1 year after stroke was significantly higher among residents of neighborhoods with the lowest NSES than those in the highest NSES neighborhoods (hazard ratio 1.77, 95% confidence interval 1.17–2.68).
Living in a socioeconomically disadvantaged neighborhood is associated with higher mortality hazard at 1 year following an incident stroke. Further work is needed to understand the structural and social characteristics of neighborhoods that may contribute to mortality in the year after a stroke and the pathways through which these characteristics operate.
PMCID: PMC3589286  PMID: 23284071
7.  Neighborhood Disadvantage and Ischemic Stroke: The Cardiovascular Health Study (CHS) 
Background and Purpose
Neighborhood characteristics may influence the risk of stroke and contribute to socioeconomic disparities in stroke incidence. The objectives of this study were to examine the relationship between neighborhood socioeconomic status (NSES) and incident ischemic stroke and examine potential mediators of these associations.
We analyzed data from 3834 whites and 785 African Americans enrolled in the Cardiovascular Health Study, a multicenter, population-based, longitudinal study of adults ages ≥65 years from four U.S. counties. The primary outcome was adjudicated incident ischemic stroke. NSES was measured using a composite of six census tract variables. Race-stratified multilevel Cox proportional hazard models were constructed, adjusted for sociodemographic, behavioral, and biologic risk factors.
Among whites, in models adjusted for sociodemographic characteristics, stroke hazard was significantly higher among residents of neighborhoods in the lowest compared to the highest NSES quartile (Hazard Ratio [HR] =1.32; 95% CI 1.01-1.72), with greater attenuation of the HR after adjustment for biologic risk factors (HR=1.16; 0.88-1.52) than for behavioral risk factors (HR=1.30; 0.99-1.70). Among African Americans, we found no significant associations between NSES and ischemic stroke.
Higher risk of incident ischemic stroke was observed in the most disadvantaged neighborhoods among whites, but not among African Americans. The relationship between NSES and stroke among whites appears to be mediated more strongly by biologic than behavioral risk factors.
PMCID: PMC3781011  PMID: 21940966
8.  Symptoms and Risk Factors for Stroke in a Community-Based Observational Sample in Viet Nam 
Viet Nam is experiencing a health transition from infectious to chronic disease. Data on cardiovascular diseases, including strokes, are limited.
Data were randomly collected from six communities in Da Nang, Viet Nam, on participant demographics, medical history, blood pressure, anthropometrics and health behavior using World Health Organization (WHO) guidelines. Stroke symptoms were collected by self-report with the standardized Questionnaire for Verifying Stroke Free Status. Multivariate logistic regression was used to identify factors associated with the presence of stroke symptoms.
1,621 adults were examined with a mean age of 52.0 years (± 12.5 years), of which 56.1% were women. 27.3% of the participants were found to have hypertension, 26.2% used tobacco, and 16.1% were overweight. More than two-thirds of the participants with hypertension were unaware of their condition. Almost one fourth of the participants were identified by the questionnaire as previously experiencing at least one stroke symptom. Age, rural residence, and education were associated with the presence of stroke symptoms. Models adjusted for demographics found hypertension, high cholesterol, reported severe chest pain, former smoking, and being overweight to be associated with a higher prevalence of stroke symptoms.
The high frequency of stroke symptoms in Da Nang calls for further evaluation and interventions to reduce hypertension and other risk factors for chronic disease.
PMCID: PMC3607634  PMID: 23538875
stroke; symptoms; Viet Nam; community-based; risk factors
9.  Common variants at 6q22 and 17q21 are associated with intracranial volume 
Nature genetics  2012;44(5):539-544.
During aging, intracranial volume remains unchanged and represents maximally attained brain size, while various interacting biological phenomena lead to brain volume loss. Consequently, intracranial volume and brain volume in late life reflect different genetic influences. Our genome-wide association study in 8,175 community-dwelling elderly did not reveal any genome-wide significant associations (p<5*10−8) for brain volume. In contrast, intracranial volume was significantly associated with two loci: rs4273712 (p=3.4*10−11), a known height locus on chromosome 6q22, and rs9915547, tagging the inversion on chromosome 17q21 (p=1.5*10−12). We replicated the associations of these loci with intracranial volume in a separate sample of 1,752 older persons (p=1.1*10−3 for 6q22 and p=1.2*10−3 for 17q21). Furthermore, we also found suggestive associations of the 17q21 locus with head circumference in 10,768 children (mean age 14.5 months). Our data identify two loci associated with head size, with the inversion on 17q21 also likely involved in attaining maximal brain size.
PMCID: PMC3618290  PMID: 22504418
10.  Birth Order and Narcolepsy Risk Among Genetically Susceptible Individuals: a Population-based Case-control Study 
Sleep Medicine  2012;13(3):310-313.
Birth order may play a role in autoimmune diseases and early childhood infections, both factors implicated in the etiology of narcolepsy. We investigated the association between birth order and narcolepsy risk in a population-based case-control study in which all study subjects were HLA-DQB1*0602 positive.
Subjects were 18-50 years old, residents of King County, Washington, and positive for HLA-DQB1*0602. Birth order was obtained from administered interviews. We used logistic regression to generate odds ratios adjusted for income and African American race.
Analyses included 67 cases (mean age 34.3 [SD=9.1], 70.2% female) and 95 controls (mean age 35.1 [SD=8.8], 58.1% female). Associations for birth order were as follows: First born (cases 38.8% vs. controls 50.2%, OR=1.0; Reference), second born (cases 29.9% vs. controls 32.9%, OR=1.6; 95% CI 0.7, 3.7), third born or higher (cases 31.3% vs. controls 16.8%, OR=2.5; 95% CI 1.0, 6.0). A linear trend was significant (p<0.05). Sibling number, sibling gender, having children, and number of children did not differ significantly between narcolepsy cases and controls.
Narcolepsy risk was significantly associated with higher birth order in this population-based study of genetically susceptible individuals. This finding supports an environmental influence on narcolepsy risk through an autoimmune mechanism, early childhood infections, or both.
PMCID: PMC3288144  PMID: 22281000
Narcolepsy; Birth order; HLA-DQB1*0602; genetics; autoimmune
11.  Markers of Inflammation in Prevalent and Incident Parkinson’s Disease in the Cardiovascular Health Study 
Parkinsonism & related disorders  2011;18(3):274-278.
Studies demonstrate existence of inflammation in prevalent Parkinson’s disease (PD). We assessed associations of baseline levels of inflammatory markers with prevalent PD at baseline (1989) and incident PD identified over 13 years of follow-up of the Cardiovascular Health Study.
Blood samples at baseline were measured for fibrinogen, interleukin-6, tumor necrosis factor–α, C-reactive protein, albumin, and white blood cells. The analysis included 60 prevalent and 154 incident PD cases.
Risk of prevalent PD was significantly higher per doubling of IL-6 among women (odds ratio [OR] = 1.5, 95% confidence interval [CI]: 1.0, 2.4) and WBC among men (OR: 2.4, 95% CI: 1.2, 4.9) in multivariate models. Risk of incident PD was not associated with higher levels of any biomarker after adjusting for age, smoking, African American race, and history of diabetes. Inverse associations with incident PD were observed per doubling of C-reactive protein (OR=0.9; 95% CI: 0.8, 1.0) and of fibrinogen among women (OR=0.4; 95% CI: 0.2, 0.8).
Although inflammation exists in PD, it may not represent an etiologic factor. Our findings suggest the need for larger studies that measure inflammatory markers before PD onset.
PMCID: PMC3288759  PMID: 22119505
albumins; C-reactive protein; inflammation; interleukin-6; odds ratio; Parkinson’s disease; tumor necrosis factor-α
12.  Gender Differences in Tea, Coffee, and Cognitive Decline in the Elderly: The Cardiovascular Health Study 
Although caffeine can enhance cognitive function acutely, long-term effects of consumption of caffeine-containing beverages such as tea and coffee are uncertain. Data on 4,809 participants aged 65 and older from the Cardiovascular Health Study (CHS) were used to examine the relationship of consumption of tea and coffee, assessed by food frequency questionnaire, on change in cognitive function by gender. Cognitive performance was assessed using serial Modified Mini-Mental State (3MS) examinations, which were administered annually up to 9 times. Linear mixed models were used to estimate rates of change in standard 3MS scores and scores modeled using item response theory (IRT). Models were adjusted for age, education, smoking status, clinic site, diabetes, hypertension, stroke, coronary heart disease, depression score, and APOE genotype. Over the median 7.9 years of follow-up, participants who did not consume tea or coffee declined annually by an average of 1.30 points (women) and 1.11 points (men) on standard 3MS scores. In fully adjusted models using either standard or IRT 3MS scores, we found modestly reduced rates of cognitive decline for some, but not all, levels of coffee and tea consumption for women, with no consistent effect for men. Caffeine consumption was also associated with attenuation in cognitive decline in women. Dose-response relationships were not linear. These longitudinal analyses suggest a somewhat attenuated rate of cognitive decline among tea and coffee consumers compared to non-consumers in women but not in men. Whether this association is causal or due to unmeasured confounding requires further study.
PMCID: PMC3577072  PMID: 21841254
Caffeine; coffee; cognition; tea
13.  Environmental tobacco smoke and Parkinson disease 
Movement Disorders  2011;27(2):293-297.
Parkinson disease is inversely associated with cigarette smoking, but its relation with passive smoking or environmental tobacco smoke exposure is rarely examined.
Within a case-control study we assessed the association between Parkinson disease and living or working with active smokers. Cases were newly diagnosed with idiopathic Parkinson disease (N=154) from western Washington State in 2002–2008. Age- and sex-matched controls (N=173) were neurologically normal and unrelated to cases.
Compared with never active or passive tobacco smokers, we observed similarly reduced Parkinson disease risks for ever passive smokers only (odds ratio=0.34, 95% confidence interval 0.16–0.73) as for ever active smokers (0.35, 0.17–0.73). Among persons whose only tobacco smoke exposure was passive smoking at home, risk was inversely associated with years exposed.
These observations parallel those well-established for active smoking. However, it remains unresolved whether a true protective effect of tobacco smoke, generally detrimental to health, underlies these associations.
PMCID: PMC3289937  PMID: 22095755
Environmental Tobacco Smoke Pollution; Idiopathic Parkinson Disease; Passive Smoking; Smoking
14.  Mid- and Late-Life Obesity: Risk of Dementia in the Cardiovascular Health Cognition Study 
Archives of neurology  2009;66(3):336-342.
To evaluate associations between mid- and late-life obesity and risk of dementia.
Prospective cohort followed 5.4 years from 1992/4 through 1999.
Community-dwelling sample in four US sites recruited from Medicare eligibility files.
2,798 adults without dementia, mean age 74.7 years, 59.1% women, participating in the Cardiovascular Health Cognition Study completing a magnetic resonance image, measured for height and weight at baseline (late-life) and self-reporting weight at age 50 (mid-life). Body mass index (BMI) was calculated at both times.
Main Outcome Measures
Dementia, Alzheimer’s disease (AD) and vascular dementia (VaD) classified by a multidisciplinary committee using standardized criteria.
Classification resulted in 480 persons with incident dementia, 245 with AD (no VaD) and 213 with VaD (with or without AD). In evaluations of mid-life obesity, an increased risk of dementia was found for obese (BMI >30) compared to normal (BMI 20-25) persons adjusted for demographics (HR: 1.39, 95% CI: 1.03-1.87) and for caradiovascularl risk factors (HR: 1.36, 95% CI: 0.94-1.95). The risk estimates reversed in assessments of late-life BMI. Underweight persons (BMI < 20) had an increased risk of dementia (HR: 1.62, 95% CI: 1.02-2.64) while being overweight (BMI 25-30) was not associated (HR: 0.92, 95% CI: 0.72-1.18) and being obese reduced the risk of dementia (HR: 0.63, 95% CI: 0.44-0.91) compared to those with normal BMI.
These results help explain the “obesity paradox” as differences in dementia risk over time are consistent with physical changes in the trajectory toward disability.
PMCID: PMC3513375  PMID: 19273752
15.  Common variants at 12q14 and 12q24 are associated with hippocampal volume 
Bis, Joshua C. | DeCarli, Charles | Smith, Albert Vernon | van der Lijn, Fedde | Crivello, Fabrice | Fornage, Myriam | Debette, Stephanie | Shulman, Joshua M. | Schmidt, Helena | Srikanth, Velandai | Schuur, Maaike | Yu, Lei | Choi, Seung-Hoan | Sigurdsson, Sigurdur | Verhaaren, Benjamin F.J. | DeStefano, Anita L. | Lambert, Jean-Charles | Jack, Clifford R. | Struchalin, Maksim | Stankovich, Jim | Ibrahim-Verbaas, Carla A. | Fleischman, Debra | Zijdenbos, Alex | den Heijer, Tom | Mazoyer, Bernard | Coker, Laura H. | Enzinger, Christian | Danoy, Patrick | Amin, Najaf | Arfanakis, Konstantinos | van Buchem, Mark A. | de Bruijn, Renée F.A.G. | Beiser, Alexa | Dufouil, Carole | Huang, Juebin | Cavalieri, Margherita | Thomson, Russell | Niessen, Wiro J. | Chibnik, Lori B. | Gislason, Gauti K. | Hofman, Albert | Pikula, Aleksandra | Amouyel, Philippe | Freeman, Kevin B. | Phan, Thanh G. | Oostra, Ben A. | Stein, Jason L. | Medland, Sarah E. | Vasquez, Alejandro Arias | Hibar, Derrek P. | Wright, Margaret J. | Franke, Barbara | Martin, Nicholas G. | Thompson, Paul M. | Nalls, Michael A. | Uitterlinden, Andre G. | Au, Rhoda | Elbaz, Alexis | Beare, Richard J. | van Swieten, John C. | Lopez, Oscar | Harris, Tamara B. | Chouraki, Vincent | Breteler, Monique M.B. | De Jager, Philip L. | Becker, James T. | Vernooij, Meike W. | Knopman, David | Fazekas, Franz | Wolf, Philip A. | van der Lugt, Aad | Gudnason, Vilmundur | Longstreth, W.T. | Brown, Mathew A. | Bennett, David A. | van Duijn, Cornelia M. | Mosley, Thomas H. | Schmidt, Reinhold | Tzourio, Christophe | Launer, Lenore J. | Ikram, M. Arfan | Seshadri, Sudha
Nature genetics  2012;44(5):545-551.
Aging is associated with reductions in hippocampal volume (HV) that are accelerated by Alzheimer’s disease and vascular risk factors. Our genome-wide association study of dementia-free persons (n=9,232) identified 46 SNPs at four loci with p-values <4.0×10-7. Two additional samples (n=2,318) replicated associations at 12q24 within MSRB3/WIF1 (discovery + replication, rs17178006; p=5.3×10-11) and at 12q14 near HRK/FBXW8 (rs7294919; p=2.9×10-11). Remaining associations included one 2q24 SNP within DPP4 (rs6741949; p=2.9×10-7) and nine 9p33 SNPs within ASTN2 (rs7852872; p=1.0×10-7) that were also associated with HV (p<0.05) in a third younger, more heterogeneous sample (n=7,794). The ASTN2 SNP was also associated with decline in cognition in a largely independent sample (n=1,563). These associations implicate genes related to apoptosis (HRK), development (WIF1), oxidative stress (MSR3B), ubiquitination (FBXW8), enzymes targeted by new diabetes medications (DPP4), and neuronal migration (ASTN2), indicating novel genetic influences that influence hippocampal size and possibly the risk of cognitive decline and dementia.
PMCID: PMC3427729  PMID: 22504421
16.  Genome-wide association studies of cerebral white matter lesion burden: the CHARGE Consortium 
Annals of neurology  2011;69(6):928-939.
White matter hyperintensities (WMH) detectable by magnetic resonance imaging (MRI)are part of the spectrum of vascular injury associated with aging of the brain and are thought to reflect ischemic damage to the small deep cerebral vessels. WMH are associated with an increased risk of cognitive and motor dysfunction, dementia, depression, and stroke. Despite a significant heritability, few genetic loci influencing WMH burden have been identified.
We performed a meta-analysis of genome-wide association studies (GWAS) for WMH burden in 9,361 stroke-free individuals of European descent from 7 community-based cohorts. Significant findings were tested for replication in 3,024 individuals from 2 additional cohorts.
We identified 6 novel risk-associated single nucleotide polymorphisms (SNPs)in one locus on chromosome 17q25 encompassing 6 known genes including WBP2, TRIM65, TRIM47, MRPL38, FBF1, and ACOX1. The most significant association was for rs3744028 (Pdiscovery= 4.0×10−9; Preplication =1.3×10−7; Pcombined =4.0×10−15). Other SNPs in this region also reaching genome-wide significance are rs9894383 (P=5.3×10−9), rs11869977 (P=5.7×10−9), rs936393 (P=6.8×10−9), rs3744017 (P=7.3×10−9), and rs1055129 (P=4.1×10−8). Variant alleles at these loci conferred a small increase in WMH burden (4–8% of the overall mean WMH burden in the sample).
This large GWAS of WMH burden in community-based cohorts of individuals of European descent identifies a novel locus on chromosome 17. Further characterization of this locus may provide novel insights into the pathogenesis of cerebral WMH.
PMCID: PMC3122147  PMID: 21681796
17.  Post Hoc Parkinson's Disease: Identifying an Uncommon Disease in the Cardiovascular Health Study 
Neuroepidemiology  2010;35(4):241-249.
Although ongoing cohort studies offer a unique opportunity to apply existing information collected prospectively to further the scientific understanding of Parkinson's disease (PD), they typically have limited information for clinical diagnosis.
We used combinations of self-report, International Classification of Diseases − 9th edition codes and antiparkinsonian medications to identify PD in the Cardiovascular Health Study. To determine whether the expected inverse association between smoking and PD is evident using our outcome definitions, we assessed baseline smoking characteristics for various definitions of PD.
We identified 60 cases with prevalent PD (1.0%; 95% confidence interval, CI = 0.8–1.3%) and 154 with incident PD by year 14. Clear associations were observed for current smokers (odds ratio, OR = 0.50; 95% CI = 0.26–0.95) and for those who smoked ≥50 pack-years (OR = 0.53; 95% CI = 0.29–0.96). Estimates for smoking were similar when ≥2 data sources were required. Estimates for self-report alone were attenuated towards null.
Using multiple data sources to identify PD represents an alternative method of outcome identification in a cohort that would otherwise not be possible for PD research. Ongoing cohort studies can provide settings in which rapid replication and explorations of new hypotheses for PD are possible.
PMCID: PMC2978249  PMID: 20881426
Cardiovascular Health Study; Cohort study; Epidemiology; International Classification of Diseases, 9th edition; Smoking; Parkinson's disease
18.  Genome-wide Analysis of Genetic Loci Associated with Alzheimer’s Disease 
Genome wide association studies (GWAS) have recently identified CLU, PICALM and CR1 as novel genes for late-onset Alzheimer’s disease (AD).
In a three-stage analysis of new and previously published GWAS on over 35000 persons (8371 AD cases), we sought to identify and strengthen additional loci associated with AD and confirm these in an independent sample. We also examined the contribution of recently identified genes to AD risk prediction.
Design, Setting, and Participants
We identified strong genetic associations (p<10−3) in a Stage 1 sample of 3006 AD cases and 14642 controls by combining new data from the population-based Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium (1367 AD cases (973 incident)) with previously reported results from the Translational Genomics Research Institute (TGEN) and Mayo AD GWAS. We identified 2708 single nucleotide polymorphisms (SNPs) with p-values<10−3, and in Stage 2 pooled results for these SNPs with the European AD Initiative (2032 cases, 5328 controls) to identify ten loci with p-values<10−5. In Stage 3, we combined data for these ten loci with data from the Genetic and Environmental Risk in AD consortium (3333 cases, 6995 controls) to identify four SNPs with a p-value<1.7×10−8. These four SNPs were replicated in an independent Spanish sample (1140 AD cases and 1209 controls).
Main outcome measure
Alzheimer’s Disease.
We showed genome-wide significance for two new loci: rs744373 near BIN1 (OR:1.13; 95%CI:1.06–1.21 per copy of the minor allele; p=1.6×10−11) and rs597668 near EXOC3L2/BLOC1S3/MARK4 (OR:1.18; 95%CI1.07–1.29; p=6.5×10−9). Associations of CLU, PICALM, BIN1 and EXOC3L2 with AD were confirmed in the Spanish sample (p<0.05). However, CLU and PICALM did not improve incident AD prediction beyond age, sex, and APOE (improvement in area under receiver-operating-characteristic curve <0.003).
Two novel genetic loci for AD are reported that for the first time reach genome-wide statistical significance; these findings were replicated in an independent population. Two recently reported associations were also confirmed, but these loci did not improve AD risk prediction, although they implicate biological pathways that may be useful targets for potential interventions.
PMCID: PMC2989531  PMID: 20460622
genome-wide association study; genetic epidemiology; genetics; dementia; Alzheimer’s disease; cohort study; meta-analysis; risk
19.  Two Simple Questions to Assess Neurologic Outcomes at Three Months after Out-of-Hospital Cardiac Arrest: Experience from the Public Access Defibrillation Trial 
Resuscitation  2010;81(5):530-533.
Two simple questions have been used to classify neurologic outcome in patients with stroke. Could they be similarly applied to patients with cardiac arrest?
As part of a randomized trial, study personnel interviewed by telephone survivors of out-of-hospital cardiac arrest to assess their outcomes three months after discharge. They asked two simple questions: 1) In the last two weeks, did you require help from another person for your everyday activities? & 2) Do you feel that you have made a complete mental recovery form your heart arrest? Next they administered the Mini-Mental State Examination (MMSE) from the Adult Lifestyles and Function Interview (ALFI) to assess cognition on a scale from 0 to 22 and the Health Utilities Index Mark 3 (HUI3) to assess quality of life on a scale from 0 (death) to 1 (perfect health).
Based on responses to the two simple questions, 32 survivors were classified as dependent (n=5, 16%), independent (n=3, 9%) and full recovery (n=24, 75%). The mean ALFI-MMSE score was 19.1 (standard deviation 5.1), and the mean HUI3 score was 0.76 (standard deviation 0.28). The classification based on the two simple questions was significantly correlated with ALFI-MMSE (p=0.002) and HUI3 (p=0.001). Scores for the HUI3 were missing in 8 survivors.
Neurologic outcomes based on the two simple questions after cardiac arrest can be easily determined, sensibly applied, and readily interpreted. These preliminary findings justify further evaluation of this simple and practical approach to classify neurologic outcome in survivors of cardiac arrest.
PMCID: PMC2856735  PMID: 20172643
heart arrest; out-of-hospital CPR; outcome; quality of life
20.  Association of Coagulation and Inflammation Related Genes and Factor VIIc Levels with Stroke: The Cardiovascular Health Study 
Thrombosis and inflammation are critical in stroke etiology, but associations of coagulation and inflammation gene variants with stroke, and particularly factor VII levels are inconclusive.
To test the associations between 736 single nucleotide polymorphisms (SNP) between tagging haplotype patterns of 130 coagulation and inflammation genes, and stroke events in the 5,888 participants ≥ 65 of the observational Cardiovascular Health Study cohort.
/Methods: With 16 years of follow-up, age and sex-adjusted Cox models were used to estimate associations of SNPs and factor VIIc levels with future stroke.
815 strokes occurred in 5,255 genotyped participants without baseline stroke (748 ischemic strokes, 586 among whites). Among whites, 6 SNPs were associated with stroke with a nominal p <0.01: rs6046 and rs3093261 (F7 gene); rs4918851 and rs3781387 (HABP2 gene); rs3138055 (NFKB1A) and rs4648004 (NFKB1). Two of these SNPs were associated with factor VIIc levels (units = percent activity): rs6046 (β = −18.5, p = 2.38 × 10−83) and rs3093261 (β = 2.99, p = 3.93 × 10−6). Adjusting for age, sex, race, and cardiovascular risk factors, the association of factor VIIc quintiles (Q) with stroke were (HR: 95% CI): Q1 (reference); Q2 (1.4; 1.1, 1.9); Q3 (1.1; 0.8, 1.5); Q4 (1.5; 1.1, 2.0); Q5 (1.6; 1.2, 2.2). Associations between SNPs and stroke were independent of factor VIIc levels.
Variation in factor VII-related genes and factor VIIc levels were associated with risk of incident ischemic stroke in this elderly cohort, suggesting a potential causal role for factor VII in stroke etiology.
PMCID: PMC3030667  PMID: 21114618
Stroke; Genetic Epidemiology; factor VII; hemostasis; inflammation; cardiovascular disease risk
21.  Genomewide Association Studies of Stroke 
The New England journal of medicine  2009;360(17):1718-1728.
The genes underlying the risk of stroke in the general population remain undetermined.
We carried out an analysis of genomewide association data generated from four large cohorts composing the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium, including 19,602 white persons (mean [±SD] age, 63±8 years) in whom 1544 incident strokes (1164 ischemic strokes) developed over an average follow-up of 11 years. We tested the markers most strongly associated with stroke in a replication cohort of 2430 black persons with 215 incident strokes (191 ischemic strokes), another cohort of 574 black persons with 85 incident strokes (68 ischemic strokes), and 652 Dutch persons with ischemic stroke and 3613 unaffected persons.
Two intergenic single-nucleotide polymorphisms on chromosome 12p13 and within 11 kb of the gene NINJ2 were associated with stroke (P<5×10−8). NINJ2 encodes an adhesion molecule expressed in glia and shows increased expression after nerve injury. Direct genotyping showed that rs12425791 was associated with an increased risk of total (i.e., all types) and ischemic stroke, with hazard ratios of 1.30 (95% confidence interval [CI], 1.19 to 1.42) and 1.33 (95% CI, 1.21 to 1.47), respectively, yielding population attributable risks of 11% and 12% in the discovery cohorts. Corresponding hazard ratios were 1.35 (95% CI, 1.01 to 1.79; P = 0.04) and 1.42 (95% CI, 1.06 to 1.91; P=0.02) in the large cohort of black persons and 1.17 (95% CI, 1.01 to 1.37; P = 0.03) and 1.19 (95% CI, 1.01 to 1.41; P = 0.04) in the Dutch sample; the results of an underpowered analysis of the smaller black cohort were nonsignificant.
A genetic locus on chromosome 12p13 is associated with an increased risk of stroke.
PMCID: PMC2768348  PMID: 19369658
22.  Active and Passive Smoking and Risk of Narcolepsy in People with HLA DQB1*0602: A Population-Based Case-Control Study 
Neuroepidemiology  2008;32(2):114-121.
We examined the risk of narcolepsy associated with active and passive smoking among genetically susceptible individuals.
We conducted a population-based case-control study in King County, Wash., USA. Between 2001 and 2005, we enrolled 67 cases through physicians and public outreach, and 95 controls through random-digit dialing. Subjects were aged between 18 and 50 years and positive for HLA DQB1*0602. All subjects were administered in-person interviews about their history of active and passive smoking.
We observed an increased risk of narcolepsy associated with having lived with two or more household smokers (odds ratio, OR = 5.1; 95% confidence interval, CI: 1.6, 12.1); with a grandparent or a sibling who smoked (OR = 3.0; 95% CI: 1.1, 8.3); with a non-family household member who smoked (OR = 3.7; 95% CI: 1.6, 8.6); and with an unrelated smoker for 1–2 years (OR = 3.1; 95% CI: 1.0, 9.0). The risk of narcolepsy was not associated with exposure to smoke at work or with active smoking before age 21 or before age of narcolepsy onset.
Passive smoking may be a risk factor for narcolepsy in subjects with HLA DQB1*0602. Future studies could help clarify whether passive smoking is an important etiologic component of narcolepsy among genetically susceptible individuals.
PMCID: PMC2970624  PMID: 19039244
Case-control study; Epidemiology; HLA-DQ antigens; Narcolepsy; Smoking
23.  Fish consumption and risk of subclinical brain abnormalities on MRI in older adults 
Neurology  2008;71(6):439-446.
To investigate the association between fish consumption and subclinical brain abnormalities.
In the population-based Cardiovascular Health Study, 3,660 participants age ≥65 underwent an MRI scan in 1992–1994. Five years later, 2,313 were scanned. Neuroradiologists assessed MRI scans in a standardized and blinded manner. Food frequency questionnaires were used to assess dietary intakes. Participants with known cerebrovascular disease were excluded from the analyses.
After adjustment for multiple risk factors, the risk of having one or more prevalent subclinical infarcts was lower among those consuming tuna/other fish ≥3 times/week, compared to <1/month (relative risk 0.74, 95% CI = 0.54–1.01, p = 0.06, p trend = 0.03). Tuna/other fish consumption was also associated with trends toward lower incidence of subclinical infarcts. Additionally, tuna/other fish intake was associated with better white matter grade, but not with sulcal and ventricular grades, markers of brain atrophy. No significant associations were found between fried fish consumption and any subclinical brain abnormalities.
Among older adults, modest consumption of tuna/other fish, but not fried fish, was associated with lower prevalence of subclinical infarcts and white matter abnormalities on MRI examinations. Our results add to prior evidence that suggest that dietary intake of fish with higher eicosapentaenoic acid and docosahexaenoic acid content, and not fried fish intake, may have clinically important health benefits.
= absolute risk reduction;
= body mass index;
= coronary heart disease;
= Cardiovascular Health Study;
= docosahexaenoic acid;
= eicosapentaenoic acid;
= food frequency questionnaire;
= high-density lipoprotein cholesterol;
= low-density lipoprotein cholesterol;
= polyunsaturated fatty acid;
= relative risk.
PMCID: PMC2676980  PMID: 18678827
24.  Quantitative assessment of subclinical spasticity in human T-cell lymphotropic virus type I infection 
Neurology  1999;53(2):386-390.
To compare human T-cell lymphotrophic virus type I (HTLV-I) seropositive and seronegative women for symptoms and signs of spasticity.
Infection with HTLV-I causes tropical spastic paraparesis/ HTLV-I–associated myelopathy (TSP/HAM). Certain populations, including female commercial sex workers (FSW), are at increased risk of developing this infection. Fewer than 5% of HTLV-I–seropositive persons develop TSP/HAM, which is typically associated with spasticity.
Cross-sectional study of 255 registered FSW in Callao, Perú, involving a questionnaire detailing demographics and neurologic symptoms, standard neurologic examination, quantitative assessment of spasticity (QSA) of muscle tone, and serologic testing for HTLV-I. Participants and examiners were blinded to serology results.
On the questionnaire and neurologic examination, none of the 32 HTLV-I–seropositive or 223 seronegative women had signs or symptoms of spasticity. However, mean values on QSA were significantly higher among seropositive women (27.1 Newton-meters/radian [N-m/r]) than among seronegative women (21.6 N-m/r, p = 0.01), indicating a subclinical increase in lower extremity tone. With values of QSA divided into tertiles, and the first tertile serving as the comparison group, the odds ratio for seropositivity was 1.4 (95% confidence interval [CI] 1.0 to 2.0) in the second and 3.1 (95% CI 2.2 to 4.3) in the third tertile, after adjusting for age and place of birth.
Although a standard neurologic evaluation could not distinguish between women with and without HTLV-I infection, QSA indicated significantly increased lower extremity tone in those with infection. Long-term follow-up will determine whether these subclinical findings in asymptomatic women progress to overt TSP/HAM.
PMCID: PMC2678023  PMID: 10430431
25.  Blood pressure control and risk of incident atrial fibrillation 
American journal of hypertension  2008;21(10):1111-1116.
Atrial fibrillation (AF) is a common arrhythmia that affects over 2 million people in the United States. We sought to determine whether the risk of incident AF among patients treated for hypertension differs by the degree of blood pressure control.
A population based, case-control study of 433 patients with verified incident AF and 899 controls was conducted to investigate the relationship between average achieved systolic (SBP) and diastolic (DBP) blood pressure and risk of AF. All patients were members of an integrated health care delivery system and were pharmacologically treated for hypertension. Medical records were reviewed to confirm the diagnosis of new onset AF and to collect information on medical conditions, health behaviors, and measured blood pressures. Average achieved SBP and DBP were calculated from the three most recent outpatient blood pressure measurements.
Compared with the reference level of 120-129 mm Hg, for categories of average achieved SBP of <120, 130-139, 140-149, 150-159, 160-169 and ≥170 mm Hg, the odds ratios (95% confidence interval) for incident AF were 1.99 (1.10, 3.62), 1.19 (0.78, 1.81), 1.40 (0.93, 2.09), 2.02 (1.30, 3.15), 2.27 (1.31, 3.93) and 1.84 (0.89, 3.80), respectively. Based on the population attributable fraction (PAF), we estimated that, among patients with treated hypertension, 17.2% (95% CI 4.3%, 28.3%) of incident AF was attributable to an average achieved SBP ≥140 mmHg.
Among patients treated for hypertension, uncontrolled elevated SBP and SBP <120 mm Hg were associated with an increased risk of incident AF.
PMCID: PMC2577029  PMID: 18756257

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