[Paleopsych] SW: Alcohol and Cognitive Function in Women

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Medical Biology: Alcohol and Cognitive Function in Women

    The following points are made by M.J. Stampfer et al (New Engl. J.
    Med. 2005 352:245):
    1) Habitual excess alcohol intake impairs the brain,[1] but the effect
    of moderate consumption is unclear. A cognitive benefit from moderate
    alcohol intake is plausible, given the strong link between moderate
    alcohol intake and the decreased risk of cardiovascular disease[2,3].
    Cognitive impairment and cardiovascular disease share common risk
    factors.[4] In addition, Ruitenberg et al[5] reported that moderate
    alcohol consumption was related to a decreased risk of both vascular
    and nonvascular dementia and proposed that moderate alcohol
    consumption may increase the release of brain acetylcholine. Most
    studies, but not all, have tended to show that moderate drinkers do
    better on cognitive tests than nondrinkers. However, few studies have
    had samples that were large enough to yield statistically significant
    results or to assess long-term stable patterns of alcohol intake and
    very early signs of cognitive decline. Also, many studies have been
    limited by inadequate control for confounding, and none have examined
    specific alcoholic beverages.
    2) The Nurses' Health Study began in 1976, when 121,700 female
    registered nurses, 30 to 55 years of age, completed a mailed
    questionnaire about their lifestyle and health. Every two years, the
    authors mailed follow-up questionnaires, and in 1980 they added a
    food-frequency questionnaire. Starting in 1995, the authors identified
    participants in the Nurses' Health Study who were 70 years of age or
    older for a study of cognitive function. Eligible women were
    community-dwelling participants without a diagnosis of stroke. Of the
    21,202 women contacted, 93 percent completed the telephone cognitive
    interview, with response rates varying by no more than 2 percent
    across categories of alcohol intake. With the exclusion of the 3
    percent of women who died after the baseline cognitive assessment, the
    authors repeated the telephone assessments of cognitive function after
    an average of 1.8 years (range, 1.3 to 5.5) in 93 percent of the
    women; 7 percent declined or were lost to follow-up. All aspects of
    the study were approved by the human research committee at Brigham and
    Women's Hospital. For the questionnaire information, the return of the
    completed questionnaire was considered to imply informed consent. For
    the telephone interview, the authors obtained oral consent. For the
    genetic substudy, the authors obtained written informed consent.
    3) The authors report that older women who consumed up to one drink
    per day had consistently better cognitive performance than
    nondrinkers. Overall, as compared with nondrinkers, women who drank
    1.0 to 14.9 g of alcohol per day had a decrease in the risk of
    cognitive impairment of approximately 20 percent. Moreover, moderate
    drinkers were less likely to have a substantial decline in cognitive
    function over a two-year period. The authors found similar inverse
    associations for all types of alcoholic beverages.
    4) The authors point out their study had several limitations. They
    could not assess the effect of high levels of alcohol intake, since
    there were few heavy drinkers in their cohort. Also, cognitive decline
    was assessed only over a two-year interval; thus, the association
    between alcohol consumption and longer-term cognitive decline could
    not be evaluated. Information on alcohol consumption was
    self-reported, perhaps leading to some misclassification. However, the
    assessment of alcohol intake was validated on the basis of dietary
    records and levels of biochemical markers and has been used to predict
    several disease outcomes in this cohort.
    5) The authors conclude their data suggest that in women up to one
    drink per day does not impair cognitive function and may actually
    decrease the risk of cognitive decline.
    References (abridged):
    1. Chick JD, Smith MA, Engleman HM, et al. Magnetic resonance imaging
    of the brain in alcoholics: cerebral atrophy, lifetime alcohol
    consumption, and cognitive deficits. Alcohol Clin Exp Res
    2. Rimm EB, Stampfer MJ. Alcohol abstinence: a risk factor for
    coronary heart disease. Heart Disease Updates 2000;2:1-9
    3. Rimm EB, Williams P, Fosher K, Criqui M, Stampfer MJ. Moderate
    alcohol intake and lower risk of coronary heart disease: meta-analysis
    of effects on lipids and haemostatic factors. BMJ 1999;319:1523-1528
    4. Breteler MM, van Swieten JC, Bots ML, et al. Cerebral white matter
    lesions, vascular risk factors, and cognitive function in a
    population-based study: the Rotterdam Study. Neurology
    5. Ruitenberg A, van Swieten JC, Witteman JC, et al. Alcohol
    consumption and risk of dementia: the Rotterdam Study. Lancet
    New Engl. J. Med. http://www.nejm.org
    Related Material:
    The following points are made by K.W. Singletary and S.M. Gapstur (J.
    Am. Med. Assoc. 2001 286:2143):
    1) The association of alcohol consumption with increased risk for
    breast cancer has been a consistent finding in a majority of
    epidemiologic studies during the past two decades. The authors
    summarize information on this association from human and animal
    investigations, with particular reference to epidemiologic data
    published since 1995.
    2) Increased estrogen and androgen levels in women consuming alcohol
    appear to be important mechanisms underlying the association. Other
    plausible mechanisms include enhanced mammary gland susceptibility to
    carcinogenesis, increased mammary carcinogen DNA damage, and greater
    metastatic potential of breast cancer cells, processes for which the
    magnitude likely depends on the amount of alcohol consumed.
    3) Susceptibility to the breast cancer-enhancing effect of alcohol may
    also be affected by other dietary factors (such as low folate intake),
    life-style habits (such as use of hormone replacement therapy), or
    biological characteristics (such as tumor hormone receptor status).
    4) Additional progress in understanding the enhancing effect of
    alcohol on breast cancer will depend on a better understanding of the
    interactions between alcohol and other risk factors and on additional
    insights into the multiple biological mechanisms involved. There is
    apparently firm evidence that in general women who consume alcohol,
    even at the level of 1 drink per day, have higher blood levels of
    estrogen (estradiol) than women who do not drink. The authors
    recommend that in general women who do not drink should not start, and
    those who do drink should do so in moderation, which is generally
    recognized to be approximately 1 drink per day.
    J. Am. Med. Assoc. http://www.jama.com
    Related Material:
    Notes by ScienceWeek:
    The consumption of alcohol (ethanol) is recognized as a major and
    potentially preventable health problem. In general, a linear
    correlation exists between the intensity of alcohol abuse in terms of
    duration and dose and the development of a wide spectrum of
    pathologies, especially liver disease. As little as 200 ml wine or 60
    ml whiskey in women, 1200 ml of 5% beer in men, when consumed on a
    daily basis over years, can produce liver injury. The mechanisms by
    which alcohol damages the liver are still unclear, but the damage is
    undisputed. Given all of the above, however, it is a fact that alcohol
    consumption has been an important aspect of Western civilization for
    thousands of years, and has probably existed for at least 10,000 years
    in various communities.
    The following points are made by Bert L. Vallee (Scientific American
    1998 June):
    1) Ethanol (ethyl alcohol) is a multifaceted entity: it may be social
    lubricant, sophisticated dining companion, cardiovascular health
    benefactor, or agent of destruction.
    2) For most of the past 10,000 years in the Western world, alcoholic
    beverages may have been the most popular and common daily drinks,
    indispensable sources of fluids and calories in a world of
    contaminated and dangerous water supplies.
    3) The experience of the East differed greatly. For at least the past
    2000 years, the practice of boiling water, usually for tea, has
    created a potable supply of non-alcoholic beverages. In addition,
    genetics plays an important role in making Asia avoid alcohol:
    approximately half of all Asian people metabolize alcohol differently
    than non-Asians, making the experience of drinking alcohol quite
    unpleasant [see background material below].
    4) Beer and wine became staples in Western societies and remained
    there until the end of the last century. Indeed, throughout Western
    history, the normal state of mind may have been one of inebriation.
    5) Although yeasts produce alcohol, they can tolerate concentrations
    of only about 16 percent, so that fermented beverages had a natural
    maximum proof. Distillation, introduced by the Arabs about 700 A.D.,
    circumvented the fermentation limit by taking advantage of alcohol's
    boiling point being lower than water (78 vs. 100 degrees centigrade)
    to boil off and then condense the alcohol from fermented mixtures.
    6) Presently, alcohol contributes to 100,000 deaths in the US each
    year, making it the 3rd leading cause of preventable mortality.
    7) Each year, approximately 12,000 children of drinking mothers are
    born with the physical signs and intellectual deficits associated with
    full-blown fetal alcohol syndrome, and thousands more suffer lesser
    8) Alcoholism, in historical terms, has only just been understood and
    accepted as a disease, and we are still coping with the historically
    recent arrival of concentrated alcohol. The author concludes: "Alcohol
    today is a substance primarily of relaxation, celebration and,
    tragically, mass destruction. To consider it as having been a primary
    agent for the development of an entire culture [Western civilization]
    may be jolting, even offensive to some. Any good physician, however,
    takes a history before attempting a cure."
    Scientific American http://www.sciam.com
    Notes by ScienceWeek:
    Ethanol is readily absorbed from the gastrointestinal tract, and more
    than 90 percent is metabolized by the liver through oxidative
    mechanism involving mainly the enzyme alcohol dehydrogenase and
    certain other enzymes. Alcohol cannot be stored and all of it is
    metabolized. Alcohol dehydrogenase oxidizes alcohol to acetaldehyde.
    Apparently, approximately 85 percent of the Japanese population has an
    atypical alcohol dehydrogenase that operates about 5 times faster than
    the same enzyme does in non-Japanese. Other Asian groups may exhibit
    the same phenomenon. Consumption of alcohol by such persons leads to
    the accumulation of acetaldehyde, resulting in extensive vasodilation,
    facial flushing, and compensatory tachycardia (rapid heartbeat greater
    than 100 per minute).

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