LETTERS * CORRESPONDANCE
We will consider for publication only letters submitted in duplicate, printed in letterquality type without proportional spacing and not exceeding 450 words. All the authors must sign a covering letter transferring copyright. Letters must not duplicate material being submitted elsewhere or already published. We routinely correspond only with authors ofaccepted letters. Rejected letters are destroyed. Accepted letters are subject to editing and abridgement.
and effective treatment chemicals. Their importance is such that any recommendations to restrict their use or levels in drinking water should be well supported. I am therefore concerned that McLachlan and associates recommend maximum levels of aluminum in drinking water without providing any rationale for these The authors of the article limits. Seules peuvent etre retenues pour publicamoved from risk evaluation have tion les lettres recues en double dont la longueur n'exce~de pas 450 mots. Elles doi- and assessment to risk managevent etre mecanographiees en qualite ((cor- ment without providing any of the respondance>> sans espacement proportion- necessary risk-benefit and socionel. Tous les auteurs doivent signer une lettre d'accompagnement portant cession economic evaluations that are des droits d'auteur. Les lettres ne doivent part (or should be part) of any rien contenir qui ait ete presente ailleurs responsible health protection recpour publication ou deja paru. En principe, ommendations. la redaction correspond uniquement avec Another concern about these les auteurs des lettres retenues pour publication. Les lettres refuses sont detruites. Les levels is that they could be interlettres retenues peuvent etre abregees ou preted as representing clear lines faire l'objet de modifications d'ordre redac- between safe and unsafe drinking tionnel. water when in reality they are based - I speculate - on minimizing aluminum exposure Aluminum and through good operating practices Alzheimer's disease at treatment plants. Aluminum-based chemicals A an environmental engi- for water treatment are used to neer involved in the devel- form particles that are removed opment of guidelines for through sedimentation and filtradrinking water quality and the tion with minimum carryover of regulation of municipal water sup- chemical or floc into the treated plies I read with interest the arti- water. A residual aluminum level cle "Would decreased aluminum in treated water of less than ingestion reduce the incidence of 50 jug/L is considered a good operAlzheimer's disease?" (Can Med ating goal but, unfortunately, is Assoc J 1991; 145: 793-804), by often difficult to achieve because Dr. Donald R. Crapper McLach- of low water temperatures or unfavourable raw water chemistry. lan and associates. Until more definitive inforThis and other studies examining the possible association be- mation is available on the tween aluminum and Alzheimer's bioavailability of the various aludisease have resulted in public minum complexes that may be concerns about the use of alumi- found in drinking water and of num-based chemicals in the treat- aluminum from other sources it is ment of drinking water. Alumi- premature and inappropriate to num sulfate and polyaluminum recommend specific limits for chloride are two very widely used total aluminum in drinking water. -
For prescribing information see page 562
When such information is available regulatory controls and limits can be established. In the interim I agree with the general thrust of the authors' recommendations: prudence dictates that unnecessary aluminum intake be reduced. In this regard water supply systems should continue to try to minimize residual aluminum levels in drinking water. David Spink, MSc, PEng Head, Municipal Branch Department of the Environment Province of Alberta Edmonton, Alta.
Dr. Crapper McLachlan and associates suggest that restricting human ingestion of aluminum would reduce the incidence of Alzheimer's disease in the elderly.
However, to get the total daily intake of aluminum below 3 mg would be very difficult. Canadian adults consume between 9 and 14 mg of aluminum daily in food alone. Most of it originates naturally in the soil and works its way through the food chain to everything from carrots to milk. In addition, even in areas that have water with a high level of aluminum the mean daily intake (from water) is less than 0.5 mg. Up to 50 mg of aluminum daily comes from food additives and aluminum-containing medications, including most antacids, buffered acetylsalicylic acid, antidiarrheal products and douches. As an environmental agent in Alzheimer's disease aluminum is almost impossible to study epidemiologically: everyone is abundantly exposed to it,' exposure is hard to measure exactly2 and Alzheimer's disease tends to be underreported and misdiagnosed. CAN MED ASSOC J 1992; 146 (4)
431
The serious toxic effects of aluminum in patients with renal disease ("dialysis dementia") led to a concern about potential problems for the general population.3 The subsequent finding of increased levels of aluminum in the brain lesions of patients with Alzheimer's disease has led to similar concerns.4,5 However, the pathological features of Alzheimer's disease are quite different from those of dialysis dementia, and in patients with uremia there is no association between dementia and the use of antacids. In patients without renal failure who receive parenteral nutrition with fluids heavily contaminated with aluminum, bone disease may develop, but encephalopathy does not.3 Alzheimer's disease is like a puzzle with a thousand pieces. Aluminum may be one of the pieces, but is it in the centre of the puzzle or out on the periphery? A causal relation between aluminum and Alzheimer's disease has not been established. Sufficient information exists to warrant further studies on the potential toxicity of aluminum, but it is not yet time to throw out the aluminum pots and pans3 or to take other extreme measures. Timothy Johnstone, MB, BS, DPH, MFCM Deputy medical health officer Capital Regional District Victoria, BC
References 1. Ganrot PO: Metabolism and possible health effects of aluminum. Environ Health Perspect 1986; 65: 363-441 2. Aluminium and Alzheimer's disease [E]. Lancet 1989; 1: 82-83 3. Sherrard DJ: Aluminum - much ado about something. N Engl J Med 1991; 324: 558-559 4. Crapper DR, Krishnan SS, Quittkat S: Aluminum, neurofibrillary degeneration and Alzheimer's disease. Brain 1976; 99: 67-80 5. Perl D, Brody A: Alzheimer's disease: x-ray spectrometric evidence of aluminum accumulation in neurofibrillary tangle-bearing neurons. Science 1980; 208: 297-299 432
CAN MED ASSOC J 1992; 146 (4)
[The authors respond:]
References
We reiterate that we do not consider aluminum to be the primary cause of Alzheimer's disease. However, considerable evidence supports the idea that aluminum is an essential neurotoxic cofactor in the development of the neurodegenerative processes involved: excess aluminum is present in neurofibrillary tangles and in association with DNA; aluminum is neurotoxic; when aluminum is injected into animals some of the biochemical and behavioural defects of Alzheimer's disease appear; intake levels of aluminum correlate with the incidence of the disease; there is a rational molecular neurotoxic mechanism; and therapy to remove aluminum from the body reverses some of the biochemical abnormalities and changes the clinical course of the disease.' A recent case-controlled epi-
1. Cowburn JD, Farrar G, Blair JA: Alzheimer's disease - some biochemical clues. Chem Britain 1990: 1169-1173 2. Neri LC, Hewitt D: Aluminum, Alzheimer's disease and drinking water. Lancet 1991; 338: 390
demiologic study2 from Ontario found that the number of hospital discharge diagnoses of Alzheimer's disease increased with the level of aluminum in the drinking water, measured by the Ontario Ministry of the Environment as an average over 12 months. This study further supports the need to critically review the use of aluminum in water treatment, food processing and pharmaceuticals. A cavalier attitude toward this neurotoxic agent in the home and the workplace is no longer acceptable. Donald R. Crapper McLachlan, MD, FRCPC Director Walter J. Lukiw, MSc Research associate Centre for Research in Neurodegenerative Diseases Theo P. Kruck, PhD Assistant professor Department of Physiology University of Toronto Sivarama S. Krishnan, PhD Scientific director Medical Physics Laboratory Toronto General Hospital Toronto, Ont.
The right to remain psychotic I n writing their reasoned and compassionate critique of the Mental Health Act of Ontario as it applies to incarcerated people with mental illness (Can Med Assoc J 1991; 145: 777-781) Drs. Robert J. McCaldon and G. Neil Conacher and Ms. Barbara J. Clark have also, perhaps unwittingly, presented an extremely disturbing document to Canadian physicians and, indeed, to Canadian society. While developing their argument that the act gives psychotic detainees inappropriate rights to refuse treatment the authors describe the consequences of such refusal. Because of their frequently disruptive behaviour such men and women are a bane to their fellow prisoners, who retaliate by such measures as dumping boiling water into the afflicted person's cell. The measured tone of the article serves as a dignified foil to the horror it describes, and it clearly emphasizes that we all know this sort of thing goes on. That someone with a chronologic age of perhaps 20 years but the maturity and control of a 5-year-old child may be routinely treated in such a fashion is a disgrace, especially since.the problem is less one of resources than of architecture and appropriate placement. It should not be impossible to protect an unwell citizen in a maximum security facility. There are dangerous men and women in society, and psychiatry has a poor record of identifying LE 15 FEVRIER 1992
We will consider for publication only letters submitted in duplicate, printed in letterquality type without proportional spacing and not exceeding 450 words. All the authors must sign a covering letter transferring copyright. Letters must not duplicate material being submitted elsewhere or already published. We routinely correspond only with authors ofaccepted letters. Rejected letters are destroyed. Accepted letters are subject to editing and abridgement.
and effective treatment chemicals. Their importance is such that any recommendations to restrict their use or levels in drinking water should be well supported. I am therefore concerned that McLachlan and associates recommend maximum levels of aluminum in drinking water without providing any rationale for these The authors of the article limits. Seules peuvent etre retenues pour publicamoved from risk evaluation have tion les lettres recues en double dont la longueur n'exce~de pas 450 mots. Elles doi- and assessment to risk managevent etre mecanographiees en qualite ((cor- ment without providing any of the respondance>> sans espacement proportion- necessary risk-benefit and socionel. Tous les auteurs doivent signer une lettre d'accompagnement portant cession economic evaluations that are des droits d'auteur. Les lettres ne doivent part (or should be part) of any rien contenir qui ait ete presente ailleurs responsible health protection recpour publication ou deja paru. En principe, ommendations. la redaction correspond uniquement avec Another concern about these les auteurs des lettres retenues pour publication. Les lettres refuses sont detruites. Les levels is that they could be interlettres retenues peuvent etre abregees ou preted as representing clear lines faire l'objet de modifications d'ordre redac- between safe and unsafe drinking tionnel. water when in reality they are based - I speculate - on minimizing aluminum exposure Aluminum and through good operating practices Alzheimer's disease at treatment plants. Aluminum-based chemicals A an environmental engi- for water treatment are used to neer involved in the devel- form particles that are removed opment of guidelines for through sedimentation and filtradrinking water quality and the tion with minimum carryover of regulation of municipal water sup- chemical or floc into the treated plies I read with interest the arti- water. A residual aluminum level cle "Would decreased aluminum in treated water of less than ingestion reduce the incidence of 50 jug/L is considered a good operAlzheimer's disease?" (Can Med ating goal but, unfortunately, is Assoc J 1991; 145: 793-804), by often difficult to achieve because Dr. Donald R. Crapper McLach- of low water temperatures or unfavourable raw water chemistry. lan and associates. Until more definitive inforThis and other studies examining the possible association be- mation is available on the tween aluminum and Alzheimer's bioavailability of the various aludisease have resulted in public minum complexes that may be concerns about the use of alumi- found in drinking water and of num-based chemicals in the treat- aluminum from other sources it is ment of drinking water. Alumi- premature and inappropriate to num sulfate and polyaluminum recommend specific limits for chloride are two very widely used total aluminum in drinking water. -
For prescribing information see page 562
When such information is available regulatory controls and limits can be established. In the interim I agree with the general thrust of the authors' recommendations: prudence dictates that unnecessary aluminum intake be reduced. In this regard water supply systems should continue to try to minimize residual aluminum levels in drinking water. David Spink, MSc, PEng Head, Municipal Branch Department of the Environment Province of Alberta Edmonton, Alta.
Dr. Crapper McLachlan and associates suggest that restricting human ingestion of aluminum would reduce the incidence of Alzheimer's disease in the elderly.
However, to get the total daily intake of aluminum below 3 mg would be very difficult. Canadian adults consume between 9 and 14 mg of aluminum daily in food alone. Most of it originates naturally in the soil and works its way through the food chain to everything from carrots to milk. In addition, even in areas that have water with a high level of aluminum the mean daily intake (from water) is less than 0.5 mg. Up to 50 mg of aluminum daily comes from food additives and aluminum-containing medications, including most antacids, buffered acetylsalicylic acid, antidiarrheal products and douches. As an environmental agent in Alzheimer's disease aluminum is almost impossible to study epidemiologically: everyone is abundantly exposed to it,' exposure is hard to measure exactly2 and Alzheimer's disease tends to be underreported and misdiagnosed. CAN MED ASSOC J 1992; 146 (4)
431
The serious toxic effects of aluminum in patients with renal disease ("dialysis dementia") led to a concern about potential problems for the general population.3 The subsequent finding of increased levels of aluminum in the brain lesions of patients with Alzheimer's disease has led to similar concerns.4,5 However, the pathological features of Alzheimer's disease are quite different from those of dialysis dementia, and in patients with uremia there is no association between dementia and the use of antacids. In patients without renal failure who receive parenteral nutrition with fluids heavily contaminated with aluminum, bone disease may develop, but encephalopathy does not.3 Alzheimer's disease is like a puzzle with a thousand pieces. Aluminum may be one of the pieces, but is it in the centre of the puzzle or out on the periphery? A causal relation between aluminum and Alzheimer's disease has not been established. Sufficient information exists to warrant further studies on the potential toxicity of aluminum, but it is not yet time to throw out the aluminum pots and pans3 or to take other extreme measures. Timothy Johnstone, MB, BS, DPH, MFCM Deputy medical health officer Capital Regional District Victoria, BC
References 1. Ganrot PO: Metabolism and possible health effects of aluminum. Environ Health Perspect 1986; 65: 363-441 2. Aluminium and Alzheimer's disease [E]. Lancet 1989; 1: 82-83 3. Sherrard DJ: Aluminum - much ado about something. N Engl J Med 1991; 324: 558-559 4. Crapper DR, Krishnan SS, Quittkat S: Aluminum, neurofibrillary degeneration and Alzheimer's disease. Brain 1976; 99: 67-80 5. Perl D, Brody A: Alzheimer's disease: x-ray spectrometric evidence of aluminum accumulation in neurofibrillary tangle-bearing neurons. Science 1980; 208: 297-299 432
CAN MED ASSOC J 1992; 146 (4)
[The authors respond:]
References
We reiterate that we do not consider aluminum to be the primary cause of Alzheimer's disease. However, considerable evidence supports the idea that aluminum is an essential neurotoxic cofactor in the development of the neurodegenerative processes involved: excess aluminum is present in neurofibrillary tangles and in association with DNA; aluminum is neurotoxic; when aluminum is injected into animals some of the biochemical and behavioural defects of Alzheimer's disease appear; intake levels of aluminum correlate with the incidence of the disease; there is a rational molecular neurotoxic mechanism; and therapy to remove aluminum from the body reverses some of the biochemical abnormalities and changes the clinical course of the disease.' A recent case-controlled epi-
1. Cowburn JD, Farrar G, Blair JA: Alzheimer's disease - some biochemical clues. Chem Britain 1990: 1169-1173 2. Neri LC, Hewitt D: Aluminum, Alzheimer's disease and drinking water. Lancet 1991; 338: 390
demiologic study2 from Ontario found that the number of hospital discharge diagnoses of Alzheimer's disease increased with the level of aluminum in the drinking water, measured by the Ontario Ministry of the Environment as an average over 12 months. This study further supports the need to critically review the use of aluminum in water treatment, food processing and pharmaceuticals. A cavalier attitude toward this neurotoxic agent in the home and the workplace is no longer acceptable. Donald R. Crapper McLachlan, MD, FRCPC Director Walter J. Lukiw, MSc Research associate Centre for Research in Neurodegenerative Diseases Theo P. Kruck, PhD Assistant professor Department of Physiology University of Toronto Sivarama S. Krishnan, PhD Scientific director Medical Physics Laboratory Toronto General Hospital Toronto, Ont.
The right to remain psychotic I n writing their reasoned and compassionate critique of the Mental Health Act of Ontario as it applies to incarcerated people with mental illness (Can Med Assoc J 1991; 145: 777-781) Drs. Robert J. McCaldon and G. Neil Conacher and Ms. Barbara J. Clark have also, perhaps unwittingly, presented an extremely disturbing document to Canadian physicians and, indeed, to Canadian society. While developing their argument that the act gives psychotic detainees inappropriate rights to refuse treatment the authors describe the consequences of such refusal. Because of their frequently disruptive behaviour such men and women are a bane to their fellow prisoners, who retaliate by such measures as dumping boiling water into the afflicted person's cell. The measured tone of the article serves as a dignified foil to the horror it describes, and it clearly emphasizes that we all know this sort of thing goes on. That someone with a chronologic age of perhaps 20 years but the maturity and control of a 5-year-old child may be routinely treated in such a fashion is a disgrace, especially since.the problem is less one of resources than of architecture and appropriate placement. It should not be impossible to protect an unwell citizen in a maximum security facility. There are dangerous men and women in society, and psychiatry has a poor record of identifying LE 15 FEVRIER 1992
