Prevalence of Parkinson's disease across North America

Estimates of the prevalence of Parkinson's disease in North America have varied widely and many estimates are based on small numbers of cases and from small regional subpopulations. We sought to estimate the prevalence of Parkinson's disease in North America by combining data from a multi-study sampling strategy in diverse geographic regions and/or data sources. Five separate cohort studies in California (2), Minnesota (1), Hawaii USA (1), and Ontario, Canada (1) estimated the prevalence of PD from health-care records (3), active ascertainment through facilities, large group, and neurology practices (1), and longitudinal follow-up of a population cohort (1). US Medicare program data provided complementary estimates for the corresponding regions. Using our age- and sex-specific meta-estimates from California, Minnesota, and Ontario and the US population structure from 2010, we estimate the overall prevalence of PD among those aged ≥45 years to be 572 per 100,000 (95% confidence interval 537-614) that there were 680,000 individuals in the US aged ≥45 years with PD in 2010 and that that number will rise to approximately 930,000 in 2020 and 1,238,000 in 2030 based on the US Census Bureau population projections. Regional variations in prevalence were also observed in both the project results and the Medicare-based calculations with which they were compared. The estimates generated by the Hawaiian study were lower across age categories. These estimates can guide health-care planning but should be considered minimum estimates. Some heterogeneity exists that remains to be understood.

Marinesco bodies and substantia nigra neuron density in Parkinson's disease

AIM

Marinesco bodies (MB) are intranuclear inclusions in pigmented neurons of the substantia nigra (SN). While rare in children, frequency increases with normal ageing and is high in Alzheimer's disease, dementia with Lewy bodies and other neurodegenerative disorders. Coinciding with the age-related rise in MB frequency is initiation of cell death among SN neurons. Whether MB have a role in this process is unknown. Our aim is to examine the association of MB with SN neuron density in Parkinson's disease (PD) in the Honolulu-Asia Aging Study.

METHODS

Data on MB and neuron density were measured in SN transverse sections in 131 autopsied men aged 73-99 years at the time of death from 1992 to 2007.

RESULTS

Marinesco body frequency was low in the presence vs. absence of PD (2.3% vs. 6.6%, P < 0.001). After PD onset, MB frequency declined as duration of PD increased (P = 0.006). Similar patterns were observed for SN neuron density. When MB frequency was low, neuron density was noticeably reduced in the SN ventrolateral quadrant, the region most vulnerable to PD neurodegeneration. Low MB frequency was unique to PD as its high frequency in non-PD cases was unrelated to parkinsonian signs and incidental Lewy bodies. Frequency was high in the presence of Alzheimer's disease and apolipoprotein ε4 alleles.

CONCLUSIONS

While findings confirm that MB frequency is low in PD, declines in MB frequency continue with PD duration. The extent to which MB have a distinct relationship with PD warrants clarification. Further studies of MB could be important in understanding PD processes.

Association of DRD2 and DRD3 polymorphisms with Parkinson's disease in a multiethnic consortium

OBJECTIVE

To examine genetic associations of polymorphisms in the dopamine receptor D2 (DRD2) and D3 (DRD3) genes with risk of Parkinson's disease (PD).

METHODS

The study included 1325 newly diagnosed patients with PD and 1735 controls from a consortium of five North American case-control studies. We collected risk factor information by in-person or telephone interview. Six DRD2 and two DRD3 polymorphisms were genotyped using a common laboratory. Odds ratios were estimated using logistic regression.

RESULTS

Among non-Hispanic whites, homozygous carriers of Taq1A DRD2 (rs1800497) polymorphism had an increased risk of PD compared to homozygous wildtype carriers (OR=1.5, 95% CI 1.0-2.3). In contrast, the direction of association for Taq1A polymorphism was opposite for African-Americans, showing an inverse association with PD risk (OR=0.10, 95% CI 0.2-0.7). Among white Hispanics who carried two alleles, the Ser9Gly DRD3 (rs6280) polymorphism was associated with a decreased risk of PD (OR=0.4, 95% CI 0.2-0.8). The inverse association of smoking with PD risk was not modified by any of the DRD2 or DRD3 polymorphisms.

CONCLUSIONS

DRD2 polymorphisms are unlikely to be true disease-causing variants; however, three DRD2 polymorphisms (including Taq1A) may be in linkage disequilibrium with possible disease associated variants in the DRD2-ANKK1-NCAM1-TTC12 gene cluster.

Coffee, ADORA2A, and CYP1A2: the caffeine connection in Parkinson's disease

BACKGROUND AND PURPOSE

In 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine animal models of Parkinson's disease (PD), caffeine protects neurons by blocking the adenosine receptor A2A (ADORA2A). Caffeine is primarily metabolized by cytochrome P450 1A2 (CYP1A2). Our objective was to examine whether ADORA2A and CYP1A2 polymorphisms are associated with PD risk or modify the caffeine-PD association.

METHODS

Parkinson's Epidemiology and Genetic Associations Studies in the United States (PEGASUS) included five population-based case-control studies. One laboratory genotyped four ADORA2A and three CYP1A2 polymorphisms in 1325 PD cases and 1735 age- and sex-matched controls. Information regarding caffeine (coffee) consumption and other lifestyle factors came from structured in-person or telephone interviews. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression.

RESULTS

Two ADORA2A polymorphisms were inversely associated with PD risk - rs71651683, a 5' variant (adjusted allelic OR = 0.51, 95% CI 0.33-0.80, permutation-adjusted P = 0.015) and rs5996696, a promoter region variant (adjusted OR for AC and CC genotypes compared with the AA wild-type genotype were 0.76 (95% CI 0.57-1.02) and 0.37 (95% CI 0.13-1.01), respectively (permutation-adjusted P for trend = 0.04). CYP1A2 polymorphisms were not associated with PD risk; however, the coffee-PD association was strongest among subjects homozygous for either variant allele rs762551 (P(interaction) = 0.05) or rs2470890 (P(interaction) = 0.04).

CONCLUSION

In this consortium study, two ADORA2A polymorphisms were inversely associated with PD risk, but there was weak evidence of interaction with coffee consumption. In contrast, the coffee-PD association was strongest among slow metabolizers of caffeine who were homozygous carriers of the CYP1A2 polymorphisms.

Effect of walking distance on 8-year incident depressive symptoms in elderly men with and without chronic disease: the Honolulu-Asia Aging Study

OBJECTIVES

To determine the effect of walking on incident depressive symptoms in elderly Japanese-American men with and without chronic disease.

DESIGN

Prospective cohort study.

SETTING

The Honolulu-Asia Aging Study.

PARTICIPANTS

Japanese-American men aged 71 to 93 at baseline.

MEASUREMENTS

Physical activity was assessed according to self-reported distance walked per day. Depressive symptoms were measured using an 11-question version of the Centers for Epidemiologic Studies Depression Scale (CES-D 11) at the fourth examination (n=3,196) and at the seventh examination 8 years later (1999/00, n=1,417). Presence of incident depressive symptoms was defined as a CES-D 11 score of 9 or greater or taking antidepressants at Examination 7. Subjects with prevalent depressive symptoms at baseline were excluded.

RESULTS

Age-adjusted 8-year incident depressive symptoms were 13.6%, 7.6%, and 8.5% for low (<0.25 miles/day), intermediate (0.25-1.5 miles/day), and high (>1.5 miles/day) walking groups at baseline (P=0.008). Multiple logistic regression analyses, adjusted for age, education, marital status, cardiovascular risk factors, prevalent diseases, and functional impairment, showed that those in the intermediate and highest walking groups had significantly lower odds of developing 8-year incident depressive symptoms (odds ratio (OR)=0.52, 95% confidence interval (CI)=0.32-0.83, P=.006 and OR=0.61, 95% CI= 0.39-0.97, P=.04, respectively). Analysis found that this association was significant only in participants without chronic diseases (coronary heart disease, cerebrovascular accident, cancer, Parkinson's disease, dementia, or cognitive impairment) at baseline.

CONCLUSION

Daily physical activity (≥0.25 mile/day) is significantly associated with lower risk of 8-year incident depressive symptoms in elderly Japanese-American men without chronic disease at baseline.

Association of fibrinogen with Parkinson disease in elderly Japanese-American men: a prospective study

BACKGROUND

The purpose of this prospective study was to examine whether fibrinogen level is associated with Parkinson disease (PD) for both prevalent and incident cases.

METHODS

The Honolulu Asia-Aging Study is a longitudinal study of Japanese-American men based on the Honolulu Heart Study birth cohort. The original cohort consisted of 8,006 participants with selective service records who were living on the island of Oahu, Hawaii, in 1965. For this analysis, baseline was defined as the 1991-1993 examination (n = 3,845) when men were aged 71-93 years old. Multivariate logistic regression and Cox proportional hazards models were used, adjusting for potential confounders.

RESULTS

We identified 61 prevalent cases and 61 incident cases of PD during the follow-up. High fibrinogen level (presence in the top quintile) was associated with higher frequency of PD for both prevalent (OR = 2.07, 95% CI = 1.10-3.88, p = 0.024) and incident cases (HR = 3.05, 95% CI = 1.34-6.97, p = 0.008) among men aged 76-93 years, after adjusting for age, smoking, and low-density lipoprotein cholesterol.

CONCLUSIONS

These results suggest high fibrinogen level is associated with increased risk of PD among men over 75 years.

Meeting report: consensus statement-Parkinson's disease and the environment: collaborative on health and the environment and Parkinson's Action Network (CHE PAN) conference 26-28 June 2007

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disorder. People with PD, their families, scientists, health care providers, and the general public are increasingly interested in identifying environmental contributors to PD risk.

METHODS

In June 2007, a multidisciplinary group of experts gathered in Sunnyvale, California, USA, to assess what is known about the contribution of environmental factors to PD.

RESULTS

We describe the conclusions around which they came to consensus with respect to environmental contributors to PD risk. We conclude with a brief summary of research needs.

CONCLUSIONS

PD is a complex disorder, and multiple different pathogenic pathways and mechanisms can ultimately lead to PD. Within the individual there are many determinants of PD risk, and within populations, the causes of PD are heterogeneous. Although rare recognized genetic mutations are sufficient to cause PD, these account for < 10% of PD in the U.S. population, and incomplete penetrance suggests that environmental factors may be involved. Indeed, interplay among environmental factors and genetic makeup likely influences the risk of developing PD. There is a need for further understanding of how risk factors interact, and studying PD is likely to increase understanding of other neurodegenerative disorders.

Serum estradiol and risk of stroke in elderly men

OBJECTIVE

To determine if levels of serum estradiol and testosterone can predict stroke in a population-based sample of elderly men.

METHODS

Serum 17beta estradiol and testosterone were measured in 2,197 men aged 71 to 93 years who participated in the Honolulu-Asia Aging Study from 1991 to 1993. All were free of prevalent stroke, coronary heart disease, and cancer. Participants were followed to the end of 1998 for thromboembolic and hemorrhagic events.

RESULTS

During the course of follow-up, 124 men developed a stroke (9.1/1,000 person-years). After age adjustment, men in the top quintile of serum estradiol (> or =125 pmol/L [34.1 pg/mL]) experienced a twofold excess risk of stroke vs men whose estradiol levels were lower (14.8 vs 7.3/1,000 person-years, p < 0.001). Among the lower quintiles, there were little differences in the risk of stroke. Findings were also significant and comparable for bioavailable estradiol and for thromboembolic and hemorrhagic events. After additional adjustment for hypertension, diabetes, adiposity, cholesterol concentrations, atrial fibrillation, and other characteristics, men in the top quintile of serum estradiol continued to have a higher risk of stroke vs those whose estradiol levels were lower (relative hazards = 2.2; 95% CI = 1.5 to 3.4, p < 0.001). Testosterone was not related to the risk of stroke.

CONCLUSIONS

High levels of serum estradiol may be associated with an elevated risk of stroke in elderly men.

Occupational and other risk factors for hand-grip strength: the Honolulu-Asia Aging Study

BACKGROUND

In certain occupations, including farm work, workers are exposed to hazardous substances, some of which are known to be toxic to the nervous system and may adversely affect muscle strength. Measurement of hand-grip strength may be useful for detecting neurotoxic exposure.

METHODS

The authors studied 3522 participants of the Honolulu Heart Program and the Honolulu-Asia Aging Study to determine whether occupational exposures to pesticides, solvents, and metals assessed at exam I (1965-68) are associated with hand-grip strength at exam IV (1991-93) and change in hand-grip strength over 25 years. Correlation, analysis of variance and covariance, and linear regression were used to evaluate the associations.

RESULTS

At exam IV, participants ranged in age from 71-93 years; mean hand-grip strength was 39.6 kg at exam I and 30.3 kg at exam IV. Over 25 years, the decline in hand-grip strength was an average of 8-9 kg for all exposures. Hand-grip strength was inversely associated with age and glucose but directly associated with cognitive function, BMI, and haemoglobin level. No other exposures were associated with hand-grip strength.

CONCLUSION

This study did not provide evidence that occupational exposure to pesticides, solvents, and metals adversely affected hand-grip strength in this population, but confirmed other important associations with hand-grip strength.

Neuropathologic findings in essential tremor

Pathologic findings, including cerebellar changes and brainstem Lewy bodies, distinguished 10 essential tremor (ET) cases from 12 controls. Numbers of torpedoes (p = 0.009) and Bergmann glia (p = 0.046) were increased in cases. Six cases (60%) had Lewy bodies vs 2 controls (16.7%) (odds ratio 7.5, 95% CI 1.04 to 54.1; p = 0.035). Four of these six had an atypical distribution of brainstem Lewy bodies. ET may be pathologically heterogeneous.

Excessive daytime sleepiness and subsequent development of Parkinson disease

OBJECTIVE

To determine if excessive daytime sleepiness (EDS) can predate future Parkinson disease (PD).

METHODS

EDS was assessed in 3,078 men aged 71 to 93 years in the Honolulu-Asia Aging Study from 1991 to 1993. All were free of prevalent PD and dementia. Follow-up for incident PD was based on three repeat neurologic assessments from 1994 to 2001.

RESULTS

During the course of follow-up, 43 men developed PD (19.9/10,000 person-years). After age adjustment, there was more than a threefold excess in the risk of PD in men with EDS vs men without EDS (55.3 vs 17.0/10,000 person-years; odds ratio [OR] = 3.3; 95% CI = 1.4 to 7.0; p = 0.004). Additional adjustment for insomnia, cognitive function, depressed mood, midlife cigarette smoking and coffee drinking, and other factors failed to alter the association between EDS and PD (OR = 2.8; 95% CI = 1.1 to 6.4; p = 0.014). Other sleep related features such as insomnia, daytime napping, early morning grogginess, and frequent nocturnal awakening showed little relation with the risk of PD.

CONCLUSIONS

Excessive daytime sleepiness may be associated with an increased risk of developing Parkinson disease.

Memory complaints in nondemented men predict future pathologic diagnosis of Alzheimer disease

The validity of memory complaints as a predictor of Alzheimer disease (AD) was assessed in 237 Japanese-American men autopsied at ages 74 to 97 years. These men were free of dementia at the time memory complaints were assessed 1 to 11 years earlier. Memory complaints were found to predict the neuropathologic diagnosis of AD after adjusting for age, time to death, education, depression, and cognitive functioning.

Consumption of milk and calcium in midlife and the future risk of Parkinson disease

OBJECTIVE

To examine the relation between milk and calcium intake in midlife and the risk of Parkinson disease (PD).

METHODS

Findings are based on dietary intake observed from 1965 to 1968 in 7,504 men ages 45 to 68 in the Honolulu Heart Program. Men were followed for 30 years for incident PD.

RESULTS

In the course of follow-up, 128 developed PD (7.1/10,000 person-years). Age-adjusted incidence of PD increased with milk intake from 6.9/10,000 person-years in men who consumed no milk to 14.9/10,000 person-years in men who consumed >16 oz/day (p = 0.017). After further adjustment for dietary and other factors, there was a 2.3-fold excess of PD (95% CI 1.3 to 4.1) in the highest intake group (>16 oz/day) vs those who consumed no milk. The effect of milk consumption on PD was also independent of the intake of calcium. Calcium from dairy and nondairy sources had no apparent relation with the risk of PD.

CONCLUSIONS

Findings suggest that milk intake is associated with an increased risk of Parkinson disease. Whether observed effects are mediated through nutrients other than calcium or through neurotoxic contaminants warrants further study.

Quantification of regional glial fibrillary acidic protein levels in Alzheimer's disease

OBJECTIVES

Our objectives were to quantify glial fibrillary acidic protein (GFAP) in brains of Alzheimer's disease (AD) cases, and non-AD controls to determine the regions with the most severe gliosis in AD.

MATERIAL AND METHODS

In a case control design, we used an enzyme-linked immunosorbent assay (ELISA) to quantify GFAP in frozen brain from four areas of neocortex in 10 AD cases, 10 age-matched controls, and 10 younger controls from the Honolulu-Asia Aging Study autopsy archive.

RESULTS

Median age at death was 83.5 years for cases and age-matched controls, and 77 years for younger controls. For the AD cases compared with the age-matched controls, levels of GFAP in occipital (P=0.01), parietal (P=0.028), and temporal lobes (P=0.004) (but not frontal) were significantly higher in the cases. The median GFAP excess in AD cases compared with age matched controls was highest in the temporal lobe.

CONCLUSIONS

Regional quantification of GFAP reveals that the glial response is most prominent in the temporal lobe in AD.

Midlife adiposity and the future risk of Parkinson's disease

BACKGROUND

Evidence suggests that nigrostriatal system disorders are associated with PD and adiposity. Whether patterns of adiposity coexist or predate clinical PD is unknown. This report examines the relation between midlife adiposity and the risk of PD.

METHODS

Measurement of adiposity occurred from 1965 to 1968 in 7,990 men in the Honolulu Heart Program (aged 45 to 68 years and without PD). Adiposity measures included body mass index (BMI), subscapular skinfold thickness (SSF), and triceps skinfold thickness (TSF). Follow-up for incident PD occurred over a 30-year period.

RESULTS

During the course of follow-up, PD was observed in 137 men. Among the measures of adiposity, age-adjusted incidence of PD increased threefold from 3.7/10,000 person-years in the bottom quartile of TSF (1 to 5 mm) to 11.1/10,000 person-years in the top quartile (11 to 32 mm, p < 0.001). Effects of TSF on PD were independent of cigarette smoking, coffee consumption, physical activity, daily caloric and fat intake, and the other measures of adiposity (p < 0.001). Whereas rates of PD were lowest in the bottom quartile of BMI and SSF vs higher quartiles, associations with PD were weaker than they were for TSF. The effect of TSF on clinical onset before age 65 years was similar to the effect that was observed in later life.

CONCLUSIONS

Increased triceps skinfold thickness measured in midlife is associated with an elevated risk of future PD. Whether patterns of adiposity reflect a unique metabolic pathology in individuals at a high risk of PD warrants further study.

Cerebral amyloid angiopathy and cognitive function: the HAAS autopsy study

OBJECTIVE

To investigate the relationship between cerebral amyloid angiopathy (CAA), dementia, and cognitive function in an autopsy sample of 211 Japanese-American men from the population-based Honolulu-Asia Aging Study.

METHODS

Starting in 1991, participants were assessed with the Cognitive Abilities Screening Instrument (CASI) and diagnosed with dementia (including subtype) based on published criteria. At autopsy, neuropathologists blinded to clinical data examined brains for neurofibrillary tangles (NFT), neuritic plaques (NP), and a number of vascular pathologies, including CAA. CAA was detected by immunostaining for betaA4 amyloid in parenchymal vessels in the neocortex and semiquantitatively rated. Linear regression models were used to examine the association of CASI score, dementia subtype, and CAA controlling for age at death, time between CASI administration and death, education, NP and NFT counts, infarcts, hemorrhage, and APOE genotype.

RESULTS

A total of 44.1% of subjects had CAA in at least one neocortical area. The presence of CAA was associated with higher mean NFT and NP counts and having at least one APOE-epsilon4 allele. The interaction between CAA and AD on the adjusted mean CASI score was significant; compared with nondemented men without CAA, the CASI score was 16.6% lower in men with AD and no CAA and 45.9% lower in men with AD plus CAA.

CONCLUSIONS

CAA may contribute to the clinical presentation of dementia by interacting with other neuronal pathologies, leading to more severe cognitive impairment in men with both CAA and AD compared with men with only AD or CAA.

Current evidence for neuroprotective effects of nicotine and caffeine against Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting 1 to 3% of individuals over the age of 65 years. While effective therapy exists for treating the bradykinesia, rigidity and tremor associated with the disease, the cause is unknown. There is no treatment available to prevent or slow the progressive neuronal loss in the substantia nigra and associated decreased levels of dopamine in the striatum that underlie the cardinal features of the disease. Both retrospective and prospective epidemiological studies have consistently demonstrated an inverse association between cigarette smoking and PD, leading to theories that smoking in general and nicotine in particular might be neuroprotective. Nicotine has been shown in animals to stimulate the release of dopamine in the striatum, and to preserve nigral neurons and striatal dopamine levels in laboratory animals with lesioned nigrostriatal pathways. Coffee and caffeine consumption have also been shown in epidemiological studies to be inversely related to PD risk. Caffeine is an adenosine A(2A) receptor antagonist that enhances locomotor activity in animal models of parkinsonism. Theophylline, a related compound that has A(2A) receptor blocking properties, has been shown in one small trial to improve motor function in patients with PD. Recently, potent and highly selective A(2A) receptor antagonists have been developed that have demonstrated improvement in motor function in animal models of parkinsonism. Exciting findings are emerging that demonstrate attenuation of dopaminergic neurotoxicity with caffeine and other adenosine receptor antagonists in mice given the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), suggesting that these compounds may be neuroprotective. Evidence for the neuroprotective potential of nicotine and caffeine is compelling, but further work is needed before testing these and related compounds in clinical trials for both individuals at high risk of developing PD and those with early, untreated disease.

Joint effect of the APOE gene and midlife systolic blood pressure on late-life cognitive impairment: the Honolulu-Asia aging study

BACKGROUND AND PURPOSE

The aim of this study was to explore the joint effect of the APOE epsilon4 allele and midlife systolic blood pressure (SBP) on the risk for poor cognitive function in late life.

METHODS

The study includes 3605 surviving members of the cohort of the Japanese-American men followed prospectively over 26 years (1965-1991) as a part of the Honolulu Heart Program. In 1965 men were aged 45 to 68 years and were living in the island of Oahu, Hawaii. For this study the sample was divided into 4 categories: normal SBP (<160 mm Hg)/No epsilon4, as the reference category; normal SBP/epsilon4; high SBP/no epsilon4; high SBP/epsilon4. The relative risk (RR) of late-life intermediate and poor cognitive function relative to good function was measured by the Cognitive Abilities Screening Instrument (CASI) test.

RESULTS

After adjusting for age, education, smoking, alcohol use, and body mass index, the RR for poor cognitive function (CASI <74) compared with good cognitive function (CASI >/=82) in never-treated subjects was 1.3 (95% CI 0.9 to 1.9) for the normal SBP/epsilon4 category, 2.6 (0.7 to 10.0) for the high SBP/no epsilon4, and 13.0 (1.9 to 83.8) for the high SBP/epsilon4. Adjustment for diabetes, prevalent stroke, coronary disease, and ankle-brachial index reduced the RR of poor cognition by 25.5% (RR 13.0 to 10.8) in those with both risk factors. In the treated group, the RR was 1.9 (0.7 to 4.5) for those with both risk factors.

CONCLUSIONS

The results suggest that midlife high SBP has a stronger adverse effect on cognitive function in persons with higher genetic susceptibility, but this effect may be modified by antihypertensive treatment.

Cholesterol and neuropathologic markers of AD: a population-based autopsy study

OBJECTIVE

To examine the association of plasma cholesterol (total and high-density [HDL] and low-density lipoprotein) levels with neuritic plaques (NP) and neurofibrillary tangles (NFT) in a population-based autopsy series of 218 Japanese American men followed as a part of the Honolulu-Asia Aging Study.

METHODS

Cholesterol levels were measured in late life (average age at death 84.6 years) in all subjects (n = 218) and in midlife (20 years before late life) in a subsample (n = 89); for the analyses, levels were categorized into quintiles, with the lowest quintile serving as the reference. Tissue from four areas of neocortex and two areas of hippocampus was prepared with Bielschowsky silver-stained sections and evaluated by one of three neuropathologists who were blinded to clinical information. Diffuse and neuritic plaques and NFT were counted in field areas standardized to 1 mm(2). Fields were selected from areas with the highest numbers of lesions, and the field with the highest count was taken to represent the brain area.

RESULTS

After adjusting for age at death, education, APOE allele, dementia, neuropathologic infarction, and blood pressure, a strong linear association was found for increasing late-life HDL cholesterol (HDL-C) levels and an increasing number of neocortical NP (5th versus 1st quintile: count ratio [95% CI] 2.30 [1.05 to 5.06]) and hippocampal (2.63 [1.25 to 5.50]) and neocortical (4.20 [1.73 to 10.16]) NFT. Trends were similar for the midlife HDL-C levels.

CONCLUSIONS

The constituents of HDL-C may play a role in the formation of AD pathology, and these processes are reflected in peripheral measures.

Ankle-brachial blood pressure in elderly men and the risk of stroke: the Honolulu Heart Program

Although low ankle/brachial blood pressure index (ABI) is a marker of generalized atherosclerosis in the elderly, it has not been identified as a risk factor for stroke. The purpose of this report is to examine the relation between ABI and stroke in elderly men. ABI was measured from 1991 to 1993 in 2767 men aged 71 to 93 years in the Honolulu Heart Program without a history of stroke and coronary heart disease. Subjects were followed for 3 to 6 years for fatal and nonfatal thromboembolic and hemorrhagic stroke. During follow-up, there were 91 strokes. There was an age-adjusted 2-fold excess in men with an ABI < 0.9 (6.0%) versus men with an ABI > or = 0.9 (2.9%, P < 0.01). Thromboembolic events occurred in 4.6% of men with an ABI < 0.9 and in 2.0% in those with an ABI > or = 0.9 (P < 0.01). Hemorrhagic stroke was also more frequent in men with a low ABI (< 0.9) versus a higher ABI (1.9 vs. 0.8%, respectively). After adjusting for other factors, the risk of total and thromboembolic strokes increased with declining ABI (P = 0.019 and P = 0.004, respectively). The relation between ABI and stroke was similar and statistically significant in the presence and absence of diabetes and hypertension (P < 0.05). Findings suggest that ABI is inversely related to the incidence of stroke. Simple measurement of ABI in an outpatient setting could be an important tool for assessing the risk of stroke in the elderly.

Resident interpretation of emergency CT scans in the evaluation of acute appendicitis

PURPOSE

Radiology resident interpretation of computed tomographic (CT) scans at academic institutions often guides management of cases of suspected acute appendicitis in the emergency department. The purpose of this study was to compare resident and faculty interpretation of CT scans obtained for acute appendicitis.

MATERIALS AND METHODS

From December 16, 1999, to July 13, 2000, CT was performed in 103 consecutive patients between the hours of 9:00 PM and 8:00 AM who were suspected of having acute appendicitis. The authors compared the residents' preliminary written interpretations with both the final reports written by the faculty and the surgical findings. The faculty interpreting the CT scans were aware of resident interpretations but were not aware that a study was being conducted.

RESULTS

The final faculty interpretation and the preliminary resident interpretation were identical in 96 of the 103 patients (93%; 95% confidence interval: 87.8%, 97.2%). In only one patient was a scan originally interpreted as negative interpreted as positive by the faculty member. Clinically, the patient did not have acute appendicitis, and surgery was not perforrmed.

CONCLUSION

In the diagnosis of acute appendicitis, image interpretations made by adequately trained radiology residents can be expected to closely match those of the radiology faculty, and the practice of after-hours interpretation of such studies by radiology residents is safe.

Frequency of bowel movements and the future risk of Parkinson's disease

BACKGROUND

Constipation is frequent in PD, although its onset in relation to clinical PD has not been well described. Demonstration that constipation can precede clinical PD could provide important clues to understanding disease progression and etiology. The purpose of this report is to examine the association between the frequency of bowel movements and the future risk of PD.

METHODS

Information on the frequency of bowel movements was collected from 1971 to 1974 in 6790 men aged 51 to 75 years without PD in the Honolulu Heart Program. Follow-up for incident PD occurred over a 24-year period.

RESULTS

Ninety-six men developed PD an average of 12 years into follow-up. Age-adjusted incidence declined consistently from 18.9/10,000 person-years in men with <1 bowel movement/day to 3.8/10,000 person-years in those with >2/day (p = 0.005). After adjustment for age, pack-years of cigarette smoking, coffee consumption, laxative use, jogging, and the intake of fruits, vegetables, and grains, men with <1 bowel movement/day had a 2.7-fold excess risk of PD versus men with 1/day (95% CI: 1.3, 5.5; p = 0.007). The risk of PD in men with <1 bowel movement/day increased to a 4.1-fold excess when compared with men with 2/day (95% CI: 1.7, 9.6; p = 0.001) and to a 4.5-fold excess versus men with >2/day (95% CI: 1.2, 16.9; p = 0.025).

CONCLUSIONS

Findings indicate that infrequent bowel movements are associated with an elevated risk of future PD. Further study is needed to determine whether constipation is part of early PD processes or is a marker of susceptibility or environmental factors that may cause PD.

beta(2)-Glycoprotein 1-dependent anticardiolipin antibodies and risk of ischemic stroke and myocardial infarction: the honolulu heart program

BACKGROUND

It has been hypothesized that immunoreactivity to beta(2)-glycoprotein 1 (beta2GP1)-dependent anticardiolipin antibody (aCL), but not beta2GP1-independent aCL, is associated with increased risk of ischemic stroke and myocardial infarction (MI).

METHODS

We performed a nested case-control study examining aCL as a risk factor for ischemic stroke and MI by using stored frozen sera obtained from subjects enrolled in the Honolulu Heart Program and followed for up for 20 years. We measured beta2GP1-dependent and beta2GP1-independent aCL and anti-beta2GP1 immunoreactivity in 259 men who developed an ischemic stroke, in 374 men who developed an MI, and in a control group of 1360 men who remained free of both conditions.

RESULTS

Only beta2GP1-dependent aCL of the IgG class was significantly associated with both incident ischemic stroke and MI. This association was attenuated in the last 5 years of the 20-year follow-up. For stroke, the risk factor-adjusted relative odds for men with a positive versus a negative beta2GP1-dependent aCL of the IgG class were 2.2 (95% CI 1.5 to 3.4) at 15 years and 1.5 (95% CI 1.0 to 2.3) at 20 years. For MI, the adjusted relative odds were 1.8 (95% CI 1.2 to 2.6) at 15 years and 1.5 (95% CI 1.1 to 2.1) at 20 years.

CONCLUSIONS

These data suggest that aCL IgG, particularly the beta2GP1-dependent variety, is an important predictor of future stroke and MI in men.

Accuracy of clinical criteria for AD in the Honolulu-Asia Aging Study, a population-based study

OBJECTIVE

To determine diagnostic accuracy for AD in a population-based study of Japanese-American men. AD is neuropathologically confirmed for more than 80% of cases at major referral centers (primarily Caucasians); however, information on diagnostic accuracy in population-based studies and studies of different ethnic groups is limited.

METHODS

There were 3,734 men who participated in the Honolulu-Asia Aging Study 1991 through 1993 dementia examination and 2,603 in the 1994 through 1996 examination. Diagnoses were based on published criteria. Neuropathologists blinded to clinical data quantified neurofibrillary tangles (NFT) and neuritic plaques (NP).

RESULTS

Of 220 autopsied subjects, clinical evaluation revealed 68 with normal cognition, 73 intermediate, and 79 with dementia: 20 AD, 27 vascular dementia, 19 AD + other, and 13 other dementia. Among 20 cases with pure AD, the median value for maximum neocortical NFT density was 6.9/mm(2) and for neocortical NP density was 8.0/mm2. Corresponding densities for other groups were <3.0/mm2. Using established neuropathologic criteria, 25% (5/20) of clinical AD cases had enough NP to meet definite AD criteria, whereas 65% (13/20) had sufficient NP to meet neuropathologic definite or probable AD criteria. Among nine AD cases with moderately severe dementia, only two (22%) had NP densities great enough to meet definite neuropathologic criteria, whereas seven (78%) met neuropathologic criteria for probable AD.

CONCLUSIONS

Neuropathologic confirmation and NP density among decedents with clinical AD in this population-based study were lower than reported by referral centers and similar to reports from two other community studies. Ethnic differences in propensity for amyloid deposition as well as differences in clinical severity and representativeness of cases might contribute to these findings.

Femtosecond fiber-feedback optical parametric oscillator

We demonstrate what is to our knowledge the first synchronously pumped high-gain optical parametric oscillator (OPO) with feedback through a single-mode fiber. This device generates 2.3-2.7 W of signal power in 700-900-fs pulses tunable in a wavelength range from 1429 to 1473 nm. The necessary high gain was obtained from a periodically poled LiTaO(3) crystal pumped with as much as 8.2 W of power at 1030 nm from a passively mode-locked Yb:YAG laser with 600-fs pulse duration and a 35-MHz repetition rate. The fiber-feedback OPO setup is compact because most of the resonator feedback path consists of a standard telecom fiber. Because of the high parametric gain, the fiber-feedback OPO is highly insensitive to intracavity losses. For the same reason, the synchronization of the cavity with the pump laser is not critical, so active stabilization of the cavity length is not required.

Metabolic cardiovascular syndrome and risk of dementia in Japanese-American elderly men. The Honolulu-Asia aging study

Cardiovascular risk factors often cluster into a metabolic syndrome that may increase the risk of dementia. The objective of the present study was to assess the long-term association between clustered metabolic cardiovascular risk factors measured at middle age and the risk of dementia in old age. This prospective cohort study of cardiovascular disease was started in 1965 and was extended to a study of dementia in 1991. The subjects were Japanese-American men with an average age of 52.7+/-4.7 (mean+/-SD) years at baseline. Dementia was diagnosed in 215 men, according to international criteria, and was based on a clinical examination, neuropsychological testing, and an informant interview. The z scores were calculated for 7 risk factors (random postload glucose, diastolic and systolic blood pressures, body mass index, subscapular skinfold thickness, random triglycerides, and total cholesterol). The relative risk (RR [95% CI]) of dementia (subtypes) per 1 SD increase in the sum of the z scores was assessed after adjustment for age, education, occupation, alcohol consumption, cigarette smoking, and years of childhood lived in Japan. The z-score sum was higher in demented subjects than in nondemented subjects, indicating a higher risk factor burden (0.74 versus -0.06, respectively; P=0. 008). Per SD increase in the z-score sum, the risk of dementia was increased by 5% (RR 1.05, 95% CI 1.02 to 1.09). The z-score sum was specifically associated with vascular dementia (RR 1.11, 95% CI 1.05 to 1.18) but not with Alzheimer's disease (RR 1.00, 95% CI 0.94 to 1.05). Clustering of metabolic cardiovascular risk factors increases the risk of dementia (mainly, dementia of vascular origin).

A longitudinal study of drinking and cognitive performance in elderly Japanese American men: the Honolulu-Asia Aging Study

OBJECTIVES

This study prospectively describes the relationships between alcohol intake and subsequent cognitive performance among participants in the Honolulu Heart Program (HHP).

METHODS

Alcohol intake was assessed at Exam III of the HHP, and cognitive performance was measured approximately 18 years later with the Cognitive Abilities Screening Instrument (CASI). Complete information was available for 3556 participants, aged 71 to 93 years at follow-up.

RESULTS

In multivariate analyses, the relationship between drinking and later cognitive performance appeared nonlinear, as nondrinkers and heavy drinkers (more than 60 ounces of alcohol per month) had the lowest CASI scores and the highest risks of poor and intermediate CASI outcomes. Compared with nondrinkers, the risk of a poor CASI score was lowered by 22% to 40% among men who consumed 1-60 ounces of alcohol per month.

CONCLUSIONS

We report a positive association between moderate alcohol intake among middle-aged men and subsequent cognitive performance in later life. However, it is possible that the health risks associated with drinking outweight any potential benefits for many elderly persons.

Ankle/brachial blood pressure in men >70 years of age and the risk of coronary heart disease

Low ankle/brachial blood pressure index (ABI) is a marker of generalized atherosclerosis in the elderly, although its association with coronary heart disease (CHD) has not been well established. The purpose of this report is to examine the relation between ABI and the risk of CHD in a sample of elderly men. Findings are based on the ABI that was measured in 2,863 Japanese-American men aged 71 to 93 years at an examination that occurred from 1991 to 1993 in the Honolulu Heart Program. All men were free of total CHD at that time and followed for nonfatal myocardial infarction and death from CHD over a 3- to 6-year period. During follow-up, 186 had a coronary event. Age-adjusted incidence declined significantly from 15.3% in men with an ABI <0.8 to 5.4% in men with an ABI >/=1.0 (p <0.001). The effect of ABI on disease was similar across a variety of risk factor strata, although it seemed strongest in the presence of hypertension and in past and current cigarette smokers. Adjustment for other risk factors failed to diminish the relation between ABI and CHD. We conclude that a low ABI increases the risk of CHD in elderly men. If findings can be extended to other elderly population segments, simple measurement of ABI in an outpatient setting could be an important tool for assessing the risk of CHD in the elderly.

Driving cessation in older men with incident dementia

OBJECTIVE

To determine the prevalence and cessation of driving among older men with incident dementia in the Honolulu-Asia Aging Study.

DESIGN

Retrospective cohort data from a community-based study of incident dementia.

SETTING

The Honolulu Heart Program and the Honolulu-Asia Aging Study.

PARTICIPANTS

A total of 643 men who were evaluated for the incidence of Alzheimer's disease or other dementia between the fourth and the fifth examination of the Honolulu Heart Program.

MEASUREMENTS

Driving history, diagnosis of dementia, grip strength, walking speed, standing balance test, interviewer's rating of vision status, and the neurologist's notes on mentions of driving behavior from informal interviews with a caregiver or family informant.

RESULTS

The prevalence of driving declined dramatically with level of cognitive functioning. Among 162 men evaluated and found to have normal cognitive functioning, 78% still drove, compared with 62% of 287 men with poor cognitive functioning but no clinical dementia, 46% of 96 men with a new diagnosis of very mild dementia (Clinical Dementia Rating = 0.5), and 22% of 98 men with a new diagnosis of mild dementia (CDR = 1). Only one of 23 men diagnosed with moderate or more severe staged incident dementia (CDR > 1) was driving. About 10% of the 59 demented persons still driving relied on co-pilots, and only one driver was reported as involved in a crash according to a review of the neurologists' notes.

CONCLUSIONS

Incident dementia is a major cause of driving cessation. Based on these data, we estimate that approximately 4% of male drivers aged 75 years and older nationwide (about 175,000 men) have dementia. This number will increase with the projected growth of drivers aged 75 years and older.

Association of coffee and caffeine intake with the risk of Parkinson disease

CONTEXT

The projected expansion in the next several decades of the elderly population at highest risk for Parkinson disease (PD) makes identification of factors that promote or prevent the disease an important goal.

OBJECTIVE

To explore the association of coffee and dietary caffeine intake with risk of PD.

DESIGN, SETTING, AND PARTICIPANTS

Data were analyzed from 30 years of follow-up of 8004 Japanese-American men (aged 45-68 years) enrolled in the prospective longitudinal Honolulu Heart Program between 1965 and 1968.

MAIN OUTCOME MEASURE

Incident PD, by amount of coffee intake (measured at study enrollment and 6-year follow-up) and by total dietary caffeine intake (measured at enrollment).

RESULTS

During follow-up, 102 men were identified as having PD. Age-adjusted incidence of PD declined consistently with increased amounts of coffee intake, from 10.4 per 10,000 person-years in men who drank no coffee to 1.9 per 10,000 person-years in men who drank at least 28 oz/d (P<.001 for trend). Similar relationships were observed with total caffeine intake (P<.001 for trend) and caffeine from non-coffee sources (P=.03 for trend). Consumption of increasing amounts of coffee was also associated with lower risk of PD in men who were never, past, and current smokers at baseline (P=.049, P=.22, and P=.02, respectively, for trend). Other nutrients in coffee, including niacin, were unrelated to PD incidence. The relationship between caffeine and PD was unaltered by intake of milk and sugar.

CONCLUSIONS

Our findings indicate that higher coffee and caffeine intake is associated with a significantly lower incidence of PD. This effect appears to be independent of smoking. The data suggest that the mechanism is related to caffeine intake and not to other nutrients contained in coffee. JAMA. 2000;283:2674-2679.

Hexagonally poled lithium niobate: A two-dimensional nonlinear photonic crystal

We report on the fabrication of what we believe is the first example of a two-dimensional (2D) nonlinear photonic crystal [Berger, Phys. Rev. Lett. 81, 4136 (1998)], where the refractive index is constant but where the 2nd order nonlinear susceptibility is spatially periodic. Such crystals allow for efficient quasi-phase-matched 2nd harmonic generation using multiple reciprocal lattice vectors. External 2nd harmonic conversion efficiencies >60% were measured with picosecond pulses. The fabrication technique is extremely versatile and should allow for the fabrication of a broad range of 2D crystals including quasicrystals.

APOE-epsilon4 predicts incident AD in Japanese-American men: the honolulu-asia aging study

The authors assessed the 3-year incidence of dementia, including subtypes, in 2,603 Japanese-American men 71 to 93 years of age who were dementia free at baseline. There were 137 new cases of dementia according to the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised, including 51 with a primary diagnosis of AD. The rates for all subtypes increased with age. Men with an APOE4 allele had a significantly increased risk of AD of 2.39 (95% CI, 1.07, 5.31), after adjusting for age and education. There was no significant relationship of APOE4 with other subtypes of dementia.

Brain aging and midlife tofu consumption

OBJECTIVE

To examine associations of midlife tofu consumption with brain function and structural changes in late life.

METHODS

The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965-1967 and 1971-1974. A 4-level composite intake index defined "low-low" consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as "high-high" consumers. Intermediate or less consistent "low" and "high" consumption levels were also defined. Cognitive functioning was tested at the 1991-1993 examination, when participants were aged 71 to 93 years (n = 3734). Brain atrophy was assessed using neuroimage (n = 574) and autopsy (n = 290) information. Cognitive function data were also analyzed for wives of a sample of study participants (n = 502) who had been living with the participants at the time of their dietary interviews.

RESULTS

Poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption. A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband's answers to food frequency questions as proxy for the wife's consumption. Statistically significant associations were consistently demonstrated in linear and logistic multivariate regression models. Odds ratios comparing endpoints among "high-high" with "low-low" consumers were mostly in the range of 1.6 to 2.0.

CONCLUSIONS

In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life.

Association of vitamin E and C supplement use with cognitive function and dementia in elderly men

OBJECTIVE

To determine whether use of vitamin E and C supplements protects against subsequent development of dementia and poor cognitive functioning.

METHODS

The Honolulu-Asia Aging Study is a longitudinal study of Japanese-American men living in Hawaii. Data for this study were obtained from a subsample of the cohort interviewed in 1982, and from the entire cohort from a mailed questionnaire in 1988 and the dementia prevalence survey in 1991 to 1993. The subjects included 3,385 men, age 71 to 93 years, whose use of vitamin E and C supplements had been ascertained previously. Cognitive performance was assessed with the Cognitive Abilities Screening Instrument, and subjects were stratified into four groups: low, low normal, mid normal, and high normal. For the dementia analyses, subjects were divided into five mutually exclusive groups: AD (n = 47), vascular dementia (n = 35), mixed/other types of dementia (n = 50), low cognitive test scorers without diagnosed dementia (n = 254), and cognitively intact (n = 2,999; reference).

RESULTS

In a multivariate model controlling for other factors, a significant protective effect was found for vascular dementia in men who had reported taking both vitamin E and C supplements in 1988 (odds ratio [OR], 0.12; 95% CI, 0.02 to 0.88). They were also protected against mixed/other dementia (OR, 0.31; 95% CI, 0.11 to 0.89). No protective effect was found for Alzheimer's dementia (OR, 1.81; 95% CI, 0.91 to 3.62). Among those without dementia, use of either vitamin E or C supplements alone in 1988 was associated significantly with better cognitive test performance at the 1991 to 1993 examination (OR, 1.25; 95% CI, 1.04 to 1.50), and use of both vitamin E and C together had borderline significance (OR, 1.18; 95% CI, 0.995 to 1.39).

CONCLUSIONS

These results suggest that vitamin E and C supplements may protect against vascular dementia and may improve cognitive function in late life.

Broadband monolithic acousto-optic tunable filter

Broadband monolithic acousto-optic tunable filters that combine a piezoelectric transducer array and an acousto-optic interaction medium in a single crystal have been investigated. A linearly chirped acoustic superlattice with an optical tuning range of lambda = 1.3-1.6 mum was formed by domain inversion in LiNbO(3) . X-propagating longitudinal acoustic waves are excited in a crossed-field scheme by a rf E(y) field applied to the superlattice and couple collinearly propagating e- and o-polarized optical modes. At mu = 1.319 mum and mu = 1.55 mum the spectral bandwidths (FWHM) were 1.54 and 2.3 nm, respectively. A relative conversion efficiency of 43%/W and a maximum conversion efficiency of 51% were measured at 1.319 mum.

The effects of childhood residence in Japan and testing language on cognitive performance in late life among Japanese American men in Hawaii

OBJECTIVES

To examine the association of years spent in Japan during childhood with cognitive test performance in late life among Japanese American men, and to assess the influence of the language used for testing on this association.

DESIGN

A cross-sectional study.

SETTING/PARTICIPANTS

A total of 3734 Japanese American men, aged 71-93 years, who were first- or second-generation migrants and living on Oahu Island, Hawaii.

MEASUREMENTS

The outcome variable was cognitive test performance assessed using the Cognitive Abilities Screening Instrument (CASI), which was developed for cross-cultural studies of cognitive impairment. The explanatory variable of main interest was the number of years spent in Japan during school-age childhood years (ages 6-17). The associations of CASI scores with childhood years in Japan was evaluated using a stepwise multiple linear regression model in which a total of 40 potential confounders were included as covariates.

RESULTS

In the total sample, there was an inverse association between CASI scores and middle childhood years in Japan. This association remained significant after controlling for age, education, socioeconomic status, traditional Japanese food consumption, pulmonary function, apolipoprotein E4, proficiency in speaking Japanese, and other possible confounders. When data were analyzed separately for subgroups according to the language preferred at testing (English or Japanese), associations between childhood years in Japan and CASI scores were in opposite directions negative for the group tested in English and positive for the group tested in Japanese. The interaction between the testing language and childhood years in Japan was statistically significant.

CONCLUSIONS

There was an inverse association between years spent in Japan during school-age years of childhood and cognitive test performance in late life. This association could not be accounted for by age, education, or other confounding factors. However, this finding was not observed in participants who preferred being tested in Japanese. To assess cognitive test performance in older people, it is of prime importance to use the most optimal language for testing, usually the subject's native language.

Midlife blood pressure and neuritic plaques, neurofibrillary tangles, and brain weight at death: the HAAS. Honolulu-Asia aging Study

Midlife hypertension is associated with later development of cognitive impairment, vascular dementia (VsD), and possibly Alzheimer's disease (AD). Neuropathic cerebrovascular lesions and brain atrophy have been associated with elevated blood pressure (BP), however, to our knowledge there have been no prospective investigations of an association of blood pressure levels measured in midlife with the microscopic lesions of AD. We investigated the relationship of BP level in midlife to development of neurofibrillary tangles (NFT), neuritic plaques (NP), and low brain weight at autopsy among Japanese-American men who were members of the Honolulu Heart Program/Honolulu-Asia aging Study (HHP/HAAS) cohort. The HHP/HAAS is a population-based, longitudinal study of cognitive function and dementia with 36 years of follow-up. Neocortical and hippocampal NFT and NP were counted per mm(2), and fixed brain weight was measured for 243 decedents. Elevated systolic BP, (> or =160 mm Hg) in midlife was associated with low brain weight and greater numbers of NP in both neocortex and hippocampus. Diastolic BP elevation, (> or =95 mm Hg) was associated with greater numbers of NFT in hippocampus. Results indicate that in addition to the accepted association of high BP with neuropathic cerebrovascular lesions, there is a direct relationship with brain atrophy, NP and NFT.

Midlife blood pressure and dementia: the Honolulu-Asia aging study

We studied the association of mid-life blood pressure to late age dementia, specifically Alzheimer's disease and vascular dementia. Data are from the cohort of 3703 Japanese-American men who were followed in the Honolulu Heart Program (HHP;1965-1971), and subsequently re-examined in 1991 for dementia. We assessed the risk (odds ratio (95% CI)) for dementia associated with categories of systolic (SBP) and diastolic blood pressure (DBP), stratified by never/ever treatment with anti-hypertensive medications, and adjusting for age, education, apolipoprotein epsilon allele, smoking and alcohol intake. Among those never treated (57% sample), the risk for dementia was OR 95% CI 3.8 (1.6-8.7) for DBP of 90-94 mm Hg, and 4. 3 (1.7-10.8) for DBP of 95 mmHg and over compared to those with DBP of 80 to 89 mm Hg. Compared to those with SBP of 110 to 139 mm Hg, the risk for dementia was 4.8 (2.0-11.0) in those with SBP 160 mm Hg and higher. Blood pressure was not associated with the risk for dementia in treated men. These results were consistent for Alzheimer's disease and vascular dementia. This study suggests elevated levels of blood pressure in middle age can increase the risk for late age dementia in men never treated with anti-hypertensive medication.

Observation of quadratic spatial solitons in periodically poled lithium niobate

We report what are to our knowledge the first observation and characterization of quadratic spatial solitons in periodically poled lithium niobate (PPLN). Using a Nd:YAG (1064-nm) source, we observed self-trapped solitary-wave propagation over more than six diffraction lengths as a result of the cascaded quadratic nonlinear process. Low-threshold operation (5-kW peak power) was measured for the quasi-phase-matched PPLN structure designed for frequency doubling.

Characterization of risk factors for vascular dementia: the Honolulu-Asia Aging Study

BACKGROUND

The Honolulu Heart Program (HHP) is a prospective study of heart disease and stroke that has accumulated risk factor data on a cohort of 8,006 Japanese American men since the study began in 1965. A recent examination of the cohort identified all patients with vascular dementia (VaD) using the criteria of the California Alzheimer's Disease Diagnostic and Treatment Center.

OBJECTIVE

To characterize patients with VaD by stroke subtype and to investigate risk factors for VaD in a cohort of Japanese American men, aged 71 to 93, living in Hawaii and participating in the HHP.

METHODS

Sixty-eight men with VaD were compared with 3,335 men without dementia or stroke (NSND). Men with VaD were also compared with 106 men with stroke who were not demented (SND). Candidate risk factors were measured prospectively.

RESULTS

Of the 68 men with VaD there were 34 (50%) whose VaD was attributed to small vessel infarcts, 16 (23%) whose VaD was related to large vessel infarcts, and 11 (16%) with both large and small vessel infarcts. The remainder could not be classified. In a multivariate logistic regression model for VaD compared with NSND containing variables found to be associated with VaD in a univariate analysis, age (odds ratio [OR] 1.19, 95% confidence interval [CI] 1.13 to 1.27), coronary heart disease (OR 2.50, 95% CI 1.35 to 4.62), and 1-hour postprandial glucose (OR 1.41, 95% CI 1.06 to 1.88) remained significantly predictive of VaD, whereas preference for a Western diet (OR 0.54, 95% CI 0.30 to 0.98) as opposed to an Oriental or mixed diet and use of supplementary vitamin E (OR 0.32, 95% CI 0.12 to 0.82) were protective. A similar model for the comparison of men with VaD and SND revealed age (OR 1.24, 95% CI 1.14 to 1.35) was predictive of VaD, whereas preference for a Western diet (OR 0.43, 95% CI 0.22 to 0.86) was protective.

CONCLUSIONS

The most common stroke subtype associated with VaD was lacunar stroke. Age and traditional vascular risk factors are important contributors to the development of VaD in late life. The antioxidant vitamin E and presently unknown factors related to a Western diet as opposed to an Oriental diet may be protective against developing VaD.

Parametric oscillator directly pumped by a 1.55-mum erbium-fiber laser

We report what is believed to be the first demonstration of an optical parametric oscillator directly pumped by the 1.55-mum output of an erbium-doped fiber laser. The oscillator, based on periodically poled lithium niobate, produced 8-muJ idler output near 3.8 mum at a 500-Hz repetition rate when it was pumped with 100-muJ 60-ns pulses at 1.55 mum . Temperature tuning of the 50-mm-long PPLN crystal gave signal and idler ranges of 2.55 to 2.7 mum and 3.65 to 3.96 mum , respectively, limited by mirror reflectivity. A signal-tuning range of 40 nm was observed for 13.5 nm of pump tuning with a fixed grating period and temperature. The optical parameter oscillator could be operated at low temperature with no sign of photorefractive damage.

Effects of walking on coronary heart disease in elderly men: the Honolulu Heart Program

BACKGROUND

Effects of walking on the risk of coronary heart disease morbidity and mortality have not been identified in the elderly. The purpose of this study was to determine whether walking is associated with a reduced risk of coronary heart disease in a sample of elderly men.

METHODS AND RESULTS

For this study, distance walked (mile/d) was examined at a baseline examination that occurred from 1991 to 1993 in the Honolulu Heart Program. Incident coronary heart disease from all causes was observed over a 2- to 4-year follow-up period. Subjects followed up were 2678 physically capable elderly men aged 71 to 93 years. During the course of follow-up, 109 men developed coronary heart disease. Men who walked <0.25 mile/d had a 2-fold increased risk of coronary heart disease versus those who walked >1. 5 mile/d (5.1% versus 2.5%; P<0.01). Men who walked 0.25 to 1.5 mile/d were also at a significantly higher risk of coronary heart disease than men who walked longer distances (4.5% versus 2.5%; P<0. 05). Adjustment for age and other risk factors failed to alter these findings.

CONCLUSIONS

Findings from the Honolulu Heart Program, which targeted physically capable elderly men, suggest that the risk of coronary heart disease is reduced with increases in distance walked. Combined with evidence that suggests that an active lifestyle reduces the risk of cardiovascular disease in younger and more diverse groups, this suggests that important health benefits could be derived by encouraging the elderly to walk.

Second-harmonic generation in a direct-bonded periodically poled LiNbO(3) buried waveguide

We report the fabrication of a 12-mum -thick periodically poled LiNbO(3) planar waveguide buried in LiTaO(3) by direct bonding of precision-polished surfaces. Frequency doubling of the 1064-nm output of a cw diode-pumped Nd:YAG laser was performed in a 5.5-mm-long device with a 6.50-mum -period grating at an elevated temperature of 174 degrees C. The resultant green second-harmonic output exhibited fundamental-spatial-mode characteristics at a 4.3%W(-1) conversion efficiency.