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1.  Disease-related and genetic correlates of psychotic symptoms in Parkinson's disease 
To examine disease-related and genetic correlates of the development of psychotic symptoms in a large Parkinson's Disease (PD) population.
We studied 500 PD subjects from the NeuroGenetics Research Consortium using logistic regression models. Predictors were demographic, clinical (motor/ non-motor features) and genetic measured as continuous or dichotomous variables. Continuous measures were divided into population based tertiles.
Results are given as odds ratios (95% confidence intervals) for dichotomous variables and by ascending tertile for continuous variables. Psychotic symptoms were associated with increasing age; 4.86 (1.62-14.30), and 6.25 (2.09-18.74) (test for trend p=.01); and duration of disease 3.81 (1.23-11.76), and 5.33 (1.68-16.89) (test for trend p=.03). For non-motor features we demonstrated positive trends with depression, 1.31 (0.47-3.61), and 5.01 (2.04-12.33) (test for trend p<.0001) and cognitive dysfunction, 0.69 (0.26-1.84) and 2.51 (1.00-6.29) (test for trend p=.03), and an excess for those with sleep disorders, 2.00 (1.03-3.89) (p=.04). Psychotic symptoms were not associated with tremor or postural instability scores but there was an association with freezing of gait, 3.83 (1.67-8.75) (p<.002). Psychotic symptoms were not associated with the presence of any examined polymorphisms in the apolipoprotein, alpha-synuclein, or MAPT genes.
This is the largest study to examine correlates of psychotic symptoms in PD. We discovered a novel association with freezing of gait. We demonstrated an association with depression and duration of disease, both of which were inconsistently related in prior studies, and confirmed the association with age, cognitive dysfunction and sleep disorders.
PMCID: PMC4216677  PMID: 21714002
Parkinson's disease; psychosis; depression; sleep; freezing of gait; genetics; risk factors
2.  High Blood Pressure and Cognitive Decline in Mild Cognitive Impairment 
To determine whether high blood pressure (BP) levels are associated with faster decline in specific cognitive domains.
Prospective longitudinal cohort.
Uniform Data Set of the National Institutes of Health, National Institute on Aging Alzheimer's Disease Centers.
One thousand three hundred eighty-five participants with a diagnosis of mild cognitive impairment (MCI) and measured BP values at baseline and two annual follow-up visits.
Neuropsychological test scores and Clinical Dementia Rating Sum of Boxes (CDR Sum) score.
Participants with MCI with two or three annual occasions of high BP values (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) had significantly faster decline on neuropsychological measures of visuomotor sequencing, set shifting, and naming than those who were normotensive on all three occasions. High systolic BP values were associated as well with faster decline on the CDR Sum score.
Hypertension is associated with faster cognitive decline in persons at risk for dementia.
PMCID: PMC3699694  PMID: 23301925
cerebrovascular disease; dementia; hypertension; mild cognitive impairment; neuropsychology
3.  Prisoner Survival Inside and Outside of the Institution: Implications for Health-Care Planning 
American Journal of Epidemiology  2011;173(5):479-487.
The life expectancy of persons cycling through the prison system is unknown. The authors sought to determine the 15.5-year survival of 23,510 persons imprisoned in the state of Georgia on June 30, 1991. After linking prison and mortality records, they calculated standardized mortality ratios (SMRs). The cohort experienced 2,650 deaths during follow-up, which were 799 more than expected (SMR = 1.43, 95% confidence interval (CI): 1.38, 1.49). Mortality during incarceration was low (SMR = 0.85, 95% CI: 0.77, 0.94), while postrelease mortality was high (SMR = 1.54, 95% CI: 1.48, 1.61). SMRs varied by race, with black men exhibiting lower relative mortality than white men. Black men were the only demographic subgroup to experience significantly lower mortality while incarcerated (SMR = 0.66, 95% CI: 0.58, 0.76), while white men experienced elevated mortality while incarcerated (SMR = 1.28, 95% CI: 1.10, 1.48). Four causes of death (homicide, transportation, accidental poisoning, and suicide) accounted for 74% of the decreased mortality during incarceration, while 6 causes (human immunodeficiency virus infection, cancer, cirrhosis, homicide, transportation, and accidental poisoning) accounted for 62% of the excess mortality following release. Adjustment for compassionate releases eliminated the protective effect of incarceration on mortality. These results suggest that the low mortality inside prisons can be explained by the rarity of deaths unlikely to occur in the context of incarceration and compassionate releases of moribund patients.
PMCID: PMC3044840  PMID: 21239522
cause of death; health status disparities; hepatitis C; mortality; prisons; prisoners; survival analysis
4.  Development of a Rapid Screening Instrument for Mild Cognitive Impairment and Undiagnosed Dementia 
Mild cognitive impairment (MCI) often presages development of Alzheimer’s disease (AD). We recently completed a cross-sectional study to test the hypothesis that a combination of a brief cognitive screening instrument (Mini-Cog) with a functional scale (Functional Activities Questionnaire; FAQ) would accurately identify individuals with MCI and undiagnosed dementia. The Mini-Cog consists of a clock drawing task and 3-item recall, and takes less than 5 minutes to administer. The FAQ is a 30-item questionnaire completed by an informant. In addition to the Mini-Cog and FAQ, a traditional cognitive test battery was administered, and two neurologists and a neuropsychologist determined a consensus diagnosis of Normal, MCI, or Dementia. A classification tree algorithm was used to pick optimal cutpoints, and, using these cutpoints, the combined Mini-Cog and FAQ (MC-FAQ) predicted the consensus diagnosis with an accuracy of 83% and a weighted kappa of 0.81. When the population was divided into Normal and Abnormal, the sensitivity, specificity and positive predictive value were 89%, 90%, and 95%, respectively. The MC-FAQ discriminates individuals with MCI from cognitively normal individuals and those with dementia, and its ease of administration makes it an attractive screening instrument to aid detection of cognitive impairment in the elderly.
PMCID: PMC2679370  PMID: 18997295
Cognitive screening; dementia; Functional Activities Questionnaire; mild cognitive impairment; Mini-Cog
5.  Evidence of shared risk for Alzheimer’s disease and Parkinson’s disease using family history 
Neurogenetics  2007;8(4):263-270.
This case-control study examined the potential for a common etiology of Parkinson’s disease (PD) and Alzheimer’s disease (AD) using reported family history. Structured interviews were used to collect AD and PD family history from subjects (n=1531) with AD, PD, AD/PD, or controls. Intergroup analysis compared reported AD and PD family histories in the three case groups to the histories reported in the control group. Intragroup analysis stratified each diagnostic group based on positive family history of AD, then compared the subgroups for a family history of PD. Subjects with AD had a higher risk of having a family history of AD [odds ratio (OR) 2.3; 1.5–3.4] and subjects with PD had a higher risk of having a family history of PD (OR 2.2; 1.2–4.0) as compared to control subjects. Intergroup analyses revealed no significant crossed risk, increased risk of subjects with AD having a family history of PD vs controls and vice versa. Intragroup analysis found that subjects with PD and a family history of AD were more likely to have a family history of PD (OR 1.7; 1.1–2.6) when compared to subjects with PD and no family history of AD. A similar trend was found for subjects with AD (OR 1.7; 0.9–3.1). AD and PD cases each have an increased familial risk of their respective disease. Probands with AD or PD and a family history of either disease have a higher crossed risk of a family history of the other disease. These findings suggest the existence of common genetic and/or environmental factors that predispose to both AD and PD in the subset of cases with positive family history of both neurodegenerative diseases.
PMCID: PMC2679377  PMID: 17805588
Neurodegenerative diseases; Familial dementia; Odds ratio; Risk assessment; Family tree
6.  Occupational Exposure to Polychlorinated Biphenyls and Risk of Breast Cancer 
Environmental Health Perspectives  2008;117(2):276-282.
Despite the endocrine system activity exhibited by polychlorinated biphenyls (PCBs), recent studies have shown little association between PCB exposure and breast cancer mortality.
To further evaluate the relation between PCB exposure and breast cancer risk, we studied incidence, a more sensitive end point than mortality, in an occupational cohort.
We followed 5,752 women employed for at least 1 year in one of three capacitor manufacturing facilities, identifying cases from questionnaires, cancer registries, and death certificates through 1998. We collected lifestyle and reproductive information via questionnaire from participants or next of kin and used semiquantitative job-exposure matrices for inhalation and dermal exposures combined. We generated standardized incidence ratios (SIRs) and standardized rate ratios and used Cox proportional hazards regression models to evaluate potential confounders and effect modifiers.
Overall, the breast cancer SIR was 0.81 (95% confidence interval, 0.72–0.92; n = 257), and regression modeling showed little effect of employment duration or cumulative exposure. However, for the 362 women of questionnaire-identified races other than white, we observed positive, statistically significant associations with employment duration and cumulative exposure; only smoking, birth cohort, and self- or proxy questionnaire completion had statistically significant explanatory power when added to models with exposure metrics.
We found no overall elevation in breast cancer risk after occupational exposure to PCBs. However, the exposure-related risk elevations seen among nonwhite workers, although of limited interpretability given the small number of cases, warrant further investigation, because the usual reproductive risk factors accounted for little of the increased risk.
PMCID: PMC2649231  PMID: 19270799
breast cancer; incidence; occupational epidemiology; polychlorinated biphenyls

Results 1-6 (6)