Effect of smoking on global cognitive function in nondemented elderly

BACKGROUND

Contrary to early case-control studies that suggested smoking protects against Alzheimer disease (AD), recent prospective studies have shown that elderly who smoke may be at increased risk for dementia.

OBJECTIVE

To examine prospectively the effect of smoking on cognition in nondemented elderly.

METHOD

In a multicenter cohort, the European Community Concerted Action Epidemiology of Dementia (EURODEM), including the Odense, Personnes Agées Quid (Paquid), Rotterdam, and Medical Research Council: Ageing in Liverpool Project-Health Aspects (MRC ALPHA) Studies, 17,610 persons aged 65 and over were screened and examined for dementia. After an average 2.3 years of follow-up, 11,003 nondemented participants were retested. Excluding incident dementia cases and those without baseline information on smoking gave an analytical sample of 9,209 persons. Average yearly decline in Mini-Mental State Examination (MMSE) score was compared among groups, adjusting for age, sex, baseline MMSE, education, type of residence, and history of myocardial infarction or stroke.

RESULTS

MMSE score of persons who never smoked on average declined 0.03 point/year. The adjusted decline of former smokers was 0.03 point greater and of current smokers 0.13 point greater than never smokers (p < 0.001). Higher rates of decline by smoking were found in men and women, persons with and without family history of dementia, and in three of four participating studies. Higher cigarette pack-year exposure was correlated with a significantly higher rate of decline.

CONCLUSION

Smoking may accelerate cognitive decline in nondemented elderly.

Education and the risk for Alzheimer's disease: sex makes a difference. EURODEM pooled analyses. EURODEM Incidence Research Group

The hypothesis that a low educational level increases the risk for Alzheimer's disease remains controversial. The authors studied the association of years of schooling with the risk for incident dementia and Alzheimer's disease by using pooled data from four European population-based follow-up studies. Dementia cases were identified in a two-stage procedure that included a detailed diagnostic assessment of screen-positive subjects. Dementia and Alzheimer's disease were diagnosed by using international research criteria. Educational level was categorized by years of schooling as low (< or =7), middle (8-11), or high (> or =12). Relative risks (95% confidence intervals) were estimated by using Poisson regression, adjusting for age, sex, study center, smoking status, and self-reported myocardial infarction and stroke. There were 493 (328) incident cases of dementia (Alzheimer's disease) and 28,061 (27,839) person-years of follow-up. Compared with women with a high level of education, those with low and middle levels of education had 4.3 (95% confidence interval: 1.5, 11.9) and 2.6 (95% confidence interval: 1.0, 7.1) times increased risks, respectively, for Alzheimer's disease. The risk estimates for men were close to 1.0. Finding an association of education with Alzheimer's disease for women only raises the possibility that unmeasured confounding explains the previously reported increased risk for Alzheimer's disease for persons with low levels of education.

Gender differences in the incidence of AD and vascular dementia: The EURODEM Studies. EURODEM Incidence Research Group

OBJECTIVE

To study the difference in risk for dementing diseases between men and women.

BACKGROUND

Previous studies suggest women have a higher risk for dementia than men. However, these studies include small sample sizes, particularly in the older age groups, when the incidence of dementia is highest.

METHODS

Pooled analysis of four population-based prospective cohort studies was performed. The sample included persons 65 years and older, 528 incident cases of dementia, and 28,768 person-years of follow-up. Incident cases were identified in a two-stage procedure in which the total cohort was screened for cognitive impairment, and screen positives underwent detailed diagnostic assessment. Dementia and main subtypes of AD and vascular dementia were diagnosed according to internationally accepted guidelines. Sex- and age-specific incidence rates, and relative and cumulative risks for total dementia, AD, and vascular dementia were calculated using log linear analysis and Poisson regression.

RESULTS

There were significant gender differences in the incidence of AD after age 85 years. At 90 years of age, the rate was 81.7 (95% CI, 63.8 to 104.7) in women and 24.0 (95% CI, 10.3 to 55.6) in men. There were no gender differences in rates or risk for vascular dementia. The cumulative risk for 65-year-old women to develop AD at the age of 95 years was 0.22 compared with 0.09 for men. The cumulative risk for developing vascular dementia at the age of 95 years was similar for men and women (0.04).

CONCLUSION

Compared with men, women have an increased risk for AD. There are no gender differences in risk for vascular dementia.

Rates and risk factors for dementia and Alzheimer's disease: results from EURODEM pooled analyses. EURODEM Incidence Research Group and Work Groups. European Studies of Dementia

OBJECTIVE

To investigate the risk of AD associated with a family history of dementia, female gender, low levels of education, smoking, and head trauma.

BACKGROUND

These putative factors have been identified in cross-sectional studies. However, those studies are prone to bias due to systematic differences between patients and control subjects regarding survival and how risk factors are recalled.

METHODS

The authors performed a pooled analysis of four European population-based prospective studies of individuals 65 years and older, with 528 incident dementia patients and 28,768 person-years of follow-up. Patients were detected by screening the total cohort with brief cognitive tests, followed by a diagnostic assessment of those who failed the screening tests. Dementia was diagnosed with the Diagnostic and Statistical Manual of Mental Disorders, 3rd ed. (revised), and AD was diagnosed according to National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria. Incident rates and relative risk (95% CI) express the association of a risk factor for dementia.

RESULTS

Incident rates for dementia and AD were similar across studies. The incidence of AD increased with age. At 90 years of age and older the incidence was 63.5 (95% CI, 49.7 to 81.0) per 1,000 person-years. Female gender, current smoking (more strongly in men), and low levels of education (more strongly in women) increased the risk of AD significantly. A history of head trauma with unconsciousness and family history of dementia did not increase risk significantly.

CONCLUSION

Contrary to previous reports, head trauma was not a risk factor for AD, and smoking did not protect against AD. The association of family history with the risk of AD is weaker than previously estimated on the basis of cross-sectional studies. Female gender may modify the risk of AD, whether it be via biological or behavioral factors.

Motor Response to Repeated Dopaminergic Stimulation in Parkinsonʼs Disease

Recent studies giving subcutaneous apomorphine or intravenous levodopa boluses have not found clear evidence of behavioral hyposensitivity to repeated dopaminergic stimulation in Parkinson's disease (PD). Here we analyze that data, and review experimental findings in animal models and our previous experience with parkinsonian patients. We conclude that acute tolerance to pulsatile stimulation is likely to play a role in the pathophysiology of motor fluctuations in PD.

Carbamazepine dose requirements during stiripentol therapy: influence of cytochrome P-450 inhibition by stiripentol

The inhibitory effect of stiripentol (STP) on disposition of carbamazepine (CBZ) and carbamazepine-10,11-epoxide (CBZE) was quantitated to establish CBZ dosage reduction guidelines for future clinical add-on efficacy trials of STP. In seven epileptic patients, STP (1,500-3,000 mg/day for 2 weeks) inhibited CBZ clearance by 50 +/- 16% (p = 0.001) and reduced the CBZE/CBZ plasma ratio by 45 +/- 14% (p = 0.0005). The inhibitory effect was gradually manifested over a period of 7-10 days after initiation of STP therapy. In contrast to inhibition of CBZE formation, STP had no effect (p greater than 0.05) on elimination clearance or half-life (t1/2) of CBZE in six healthy volunteers. STP most likely exerts inhibitory effects through inhibition of cytochrome P-450. This hypothesis was confirmed in the present study by the finding that a therapeutic concentration of STP (7 micrograms/mL) inhibited 10,11-epoxidation of CBZ in human liver microsomes by 40-50%. On the basis of results from this study, we propose that (a) CBZ dosage should be reduced in steps over a period of 7-10 days after initiation of STP, and (b) a CBZ dosage of 4.3 to 8.7 mg/kg/day will maintain therapeutic CBZ plasma levels of 5-10 micrograms/mL.

Motor complications associated with chronic levodopa therapy in Parkinson's disease

Fluctuations and dyskinesias are the 2 main motor complications associated with chronic levodopa therapy. Striatal denervation following degeneration of the substantia nigra dopaminergic projections is probably the major pathophysiologic mechanism underlying motor fluctuations. In addition, pathologic modification of striatal receptors, partially related to the nonphysiologic delivery of levodopa in a discontinuous pulsatile mode, may be responsible for the various types of dyskinesias and sudden "off" episodes. Drugs capable of providing a stable dopaminergic stimulation should be particularly useful for preventing the development of motor complications in patients not yet treated. At the other end of the clinical spectrum, patients with complex fluctuations are the least likely to improve with slow-release levodopa preparations.

Hemi-dystonia secondary to localised basal ganglia tumour

An 8-year-old boy with an 18 month history of left limb hemi-dystonia due to a right lenticular nucleus astrocytoma originating in the putamen is reported. Subsequent neuropathological study demonstrated that the tumour was mainly localised to the right lenticular nucleus, with cystic necrosis in the infero-lateral putamen. Solid tumour also infiltrated the right hypothalamus, the anterior commisure and the optic chiasm, and there was perivascular spread into the globus pallidus, internal capsule and roof of the right lateral ventricle. This case, and the few other published reports of symptomatic dystonia due to focal brain lesions verified pathologically, indicate that damage to the lenticular nucleus, and to the putamen in particular, can cause limb dystonia in man.

A case of Charcot-Marie-Tooth disease mimicking Friedreich's ataxia: is there any association between friedreich's ataxia and Charcot-Marie-Tooth disease?

The authors report a case of Charcot-Marie-Tooth disease that mimicked Friedreich's ataxia and featured impaired tendon reflexes in the limbs, incoordination mimicking cerebellar disease in the extremities, extensor plantar responses on both sides, bilateral foot deformity, imparied position sense in the toes, absent vibratory sense in the distal parts of the legs and minimal distal weakness with wasting. Motor conduction velocity in the upper limbs was substantially reduced. Other cases similar in nature reported in the literature resemble spino-cerebellar degeneration in general, and Friedreich's ataxia, in particular. It is emphasized that the natural history, EMG, motor conduction velocity studies and examination of other affected members of the family permit the correct diagnosis to be made in such cases. It is also emphasized that patients similar to the one reported here may also resemble, and should be differentiated from, cases of familial dorsal column ataxia (Biemond type). Stress is put upon the fact that when Charcot-Marie-Tooth disease mimicks spino-cerebellar degeneration, substantial slowing of motor conduction in the upper limbs is generally sufficient to establish the diagnosis. The relation between Friedreich's ataxia an Charcot-Marie-Tooth disease is reviewed and it is concluded that these two disorders are distinct clinical and pathological entities.

The vestibulospinal system and postural regulation in man

Upright posture in humans represents a giant step phylogenetically speaking. But upright posture demands refined mechanisms for static and dynamic postural equilibrium that are initiated by the concurrence of visual and proprioceptive impulses from the muscles of the legs and the labyrinth. The static labyrinth and Deiter's nucleus via the LVST seem to be the main centers responsible for static equilibrium. Its basic neurophysiological mechanism has been analyzed by the study of stretch reflexes, which permits a semiquantitative evaluation of the function of the static labyrinth. The cerebellum appears as the main control center of the proprioceptive system in relation to dynamic equilibrium.

The neurological complications of brucellosis

Neurological complications of brucellosis have seldom been reported. Typical cases of meningoencephalitis, myelitis, and peripheral nerve involvement due to brucellosis, which have been collected over the past ten years, are described. Only four cases of extradural brucellar abcesses have been published previously. We now add four new observations. A CSF electrophoresis was done in the cases of meningoencephalitis and meningomyelitis and showed a marked increased of gamma globulin. This has never been reported previously.