Alcohol and brain damage: cause or association?

Alcohol consumption and incidence of dementia in a community sample aged 75 years and older

To explore the relationship between light to moderate alcohol consumption and risk of dementia and Alzheimer's disease in very old people, a community-based dementia-free cohort (n = 402) was followed for almost 6 years to detect incident dementia using the Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition-Revised criteria. Data from the entire cohort and a subpopulation of those with baseline Mini-Mental State Examination score > or =24 (n = 317) were analyzed with Cox models. In the entire population, light to moderate drinking was significantly associated with a decreased risk of incident dementia and Alzheimer's disease compared with nondrinking (adjusted relative risk 0.5, 95% confidence interval 0.3 to 0.7). In the analysis of the subpopulation, however, the inverse association between light to moderate drinking and risk of incident dementia and Alzheimer's disease was less evident and no longer statistically significant. This study suggested that light to moderate alcohol drinking might protect against dementia and Alzheimer's disease among old people, although the possibility that such an association may be due to information bias cannot be totally ruled out.

Prospective association of smoking and alcohol use with cognitive function in an elderly cohort

Cross-sectional studies of the associations of alcohol and tobacco use with cognitive function do not take into account behavior change after memory loss or differential survival. This prospective study examines the association of cigarette smoking and alcohol consumption at baseline with risk of poor cognitive function 13-18 years later. Between 1973 and 1975, 1469 relatively well-educated, noninstitutionalized men and women from Rancho Bernardo, California, answered standardized questions about smoking and alcohol consumption. Between 1988 and 1991, 511 of these men and women completed five standardized cognitive function tests. At baseline, 20.4% of the men and 23.0% of the women were cigarette smokers. Smoking was associated with increased mortality in men but not in women. In surviving male participants, cognitive function test scores did not significantly differ by baseline smoking status. Among female participants, smoking was associated with categorically defined poorer function on two of five tests. At baseline, 16% of the men and 29% of the women were nondrinkers. Drinking more than two drinks per day was associated with decreased mortality in both sexes. Among women, increasing consumption of alcohol predicted a significant decline in the long-term recall and savings scores of the visual reproduction test. Moderate drinking, approximately two drinks per day, predicted categorically defined poor performance on the Buschke long-term recall task in women. Alcohol consumption was not associated with cognitive function in men. Overall, the observed associations were weak, and no clear pattern was observed. Although there were some gender differences in observed associations and a survivor effect cannot be excluded, data from these healthy, educated, noninstitutionalized people offer no compelling evidence that social drinking or cigarette smoking causes or prevents impaired cognitive function in old age. The large number of comparisons and inconsistent results suggest that the few statistically significant findings may be spurious. Additional long-term prospective studies are needed to determine the generalizability of these findings to individuals in less healthy or less well-educated cohorts.

Brain impairment in social drinkers? No cause for concern

Correlations between measures of alcohol consumption and cognitive test scores have been interpreted to reflect a chronic toxic effect of ethanol on brain function in light to moderate social drinkers. However, the data indicate that there is little support across research groups for any specific relationship and, at best, the effect of alcohol consumption accounts for only a small proportion of variance. Consideration of test validity suggests that the principal measure of ability used in this research is not capable of elucidating cerebral deficit. Further, the pattern of observed correlations is not consistent with the assumption that the putative effects of social drinking involve deficits less severe but similar in type to those seen in chronic alcoholics. Instead, an association between innate ability, demographic variables, and drinking behavior in the general population is the most parsimonious explanation of all the data.

Alcohol use and depression symptoms among employed men and women

A representative sample of 1,367 employed men and women in Detroit responded to questions about drinking practices and symptoms of depression. After controlling for age, education, family income, marital status, medication use, fathers' drinking, and other variables, increased quantity of alcohol consumed per drinking occasion was associated with increased depression symptoms in the sober state among men and women. Depression symptoms may be one of a group of not fully identified drug after-effect disorders involving psychological functioning.

Neurobehavioural effects of occupational exposure to organic solvents among construction painters

A cross sectional study of 101 construction painters was performed to investigate the relation between exposure to mixed organic solvents and changes in central nervous system function. Solvent exposure was estimated using questionnaire data to derive an exposure index (a measure of intensity of exposure) and to estimate the duration and frequency of exposure. Adverse effects on the central nervous system were assessed by self reported questionnaires and eight tests of a computer administered neurobehavioural evaluation system. Factor analysis of both measures of effect yielded factors both biologically plausible and in agreement with other empirical evidence. A consistent positive association was observed between most measures of exposure and the occurrence of neurotoxic symptoms, notably dizziness, nausea, fatigue, problems with arm strength, and feelings of getting "high" from chemicals at work. Associations with exposure were found with the neurobehavioural evaluation system tests of symbol digit substitution and digit span; however, no consistent pattern of effect on neurobehavioural function was observed. This pattern of the occurrence of neurotoxic symptoms without clear evidence of function deficit is consistent with the type 1 toxic central nervous system disorder as classified by the World Health Organisation.

Alcohol intake in a healthy elderly population

The relationship between amount of alcohol consumption and social, psychological, and cognitive status was examined in 270 healthy, independently living men and women over age 65. Forty-eight per cent of the sample recorded some alcohol intake during a three-day diet record, with 8 per cent drinking 30 or more grams of alcohol daily. Alcohol intake was positively associated with male gender, income, and amount of education and negatively associated with age. Alcohol intake was not associated with any changes in social or psychological status, but was positively associated with several measurements of cognitive status. These correlations were weak, however, and tended to disappear after controlling for income, education, gender, and age. Past alcohol intake was not associated with any indicators of present social, psychological, or cognitive functioning.