Deliberate poisoning of drinking water.
On this issue of fluoride, the Australian government ranks as the world’s most maliciously corrupt crime gang of the modern era. All authentic science unequivocally condemns this evil practice. The neurotoxin of hydrofluorosilicic acid is equally as toxic as arsenic and lead and should never be added to public water. After reporting water fluoridation as a crime-in-progress to the WA police my request for remedial action was promptly dismissed as not being a police matter. This arbitrary response furthered widespread alarm among the mass of citizenry deeply concerned with the demonstrable crime of water fluoridation. Any claim that this community concern of a crime-in-progress is not a police matter is conspicuously incorrect since the primary purpose of police is the prevention of crime. So far as I’m aware police do not exist to protect crime but rather prevent it. Or at least that’s what we the public pay them for. Sadly they now exclusively function as predatory corporate mercenaries.
The deliberate poisoning of public water with hazardous toxic industrial waste under the internationally discredited pretext of improving dental health is the most monstrous crime imaginable. It’s a known criminal scam perpetrated by criminal scum. Reliable studies establish a causal link between fluoridation and cancer, genetic damage, neurological impairment and bone pathology. This incontestable evidence has resulted in 98% of the world banning fluoridation reinforced by the world’s foremost authority on dentistry, the international academy of dentistry, oral hygiene and toxicology; emphatically condemning the dangerous practice. However evil has no regard for truth and will stop at nothing to destroy it.
Further peer-reviewed independent studies link fluoride exposure to unsightly dental fluorosis, lowered IQ in children and measurably worse. Vicious socio-psychopaths inflicting this evil upon the Australian public against the overwhelming majority will and in the full knowledge of the proven harm is unmistakably a criminal act. Not only is water fluoridation a malicious crime but is described by leading experts as the most massive and far reaching scientific hoax in recorded history. The Covid-19 scam now equals that shameful metric.
Furnishing police with incontestable evidence, I’ve posted by registered mail a leading scientific literature review by Dr Geoff Pain confirming beyond doubt the clear and present danger presented by water fluoridation. Also enclosed is a DVD documentary representing just one of countless investigations, comprehensive studies, books, expose’s and video documentaries establishing the criminal nature of this unmitigated evil. This indisputable evidence is presented to the WA police department, Minister for health, Attorney General’s Office and the minister for water as an official reporting of a crime-in-progress. Unsurprisingly no remedial action will ensue from agencies mandated to protect public health. In a satanic inversion agencies mandated to protect health do everything they can to impair, degrade and destroy it in a program of ongoing genocide.
The established proof of harm lawfully demands the immediate banning of fluoridation followed by prompt, purposeful and effective police investigation. Mounting an unassailable case against this obvious crime would be effortless, but police investigators criminally ignore their oath of office to serve and protect the public. Instead they refuse prosecuting this obvious crime. Police no longer serve the Australian public but are co-opted to function as a mercenary force of predatory parasites shielding the plunder of global corporatism while actively covering up the malevolent crime of fluoridation – and much else besides.
When seeking to enforce fluoridation against emphatic public objections government thugs use the Delphi technique at meetings in order to ensure a pre-determined outcome which unfailingly overrides community objections. I’ve attended a number of these government-sponsored meetings which are falsely advertised as ‘community consultation’ but in reality are contrived to stifle public opinion to unlawfully railroad the crime of water fluoridation. The rule of law will only be restored through enough noble minded people using right intention to make it happen. Nearly 2,000 published scientific studies have reported adverse effects of fluoride on almost every organ and tissue in the human body. The influence of fluoridation chemicals on our physiology is pervasive. We list 10 major harms of fluoride.
Story at a glance: Ten major harms of fluoridation chemicals
Steadily accumulating scientific evidence, especially a substantial increase in fluoride-toxicity studies in the last 15 years, is clearly reinforcing the toxicity of fluoridation chemicals and the long-term damage they can do to our physiology. Today there is already a substantial body of scientific evidence undeniably refuting forced water fluoridation – enough to discontinue this absurd practice immediately. The final rejection of this bizarre health intervention, however, is still yet to overcome a wall of entrenched policy, reputational protection, bureaucratic self-righteousness, and biased self-interests. Every week it seems another study is published emphasizing that fluoride consumed regularly in low dosage is detrimental to our health. Since the last review on fluoride conducted by Australia’s National Health and Medical Research Council in 2017, more than 400 new human and animal studies have reinforced this view. In fact to date, more than 1,900 individual published, peer-reviewed scientific studies and reviews showing fluoridation chemicals can damage the developing brain, bones/joints, teeth, eyes, kidneys, thyroid gland and pineal gland, cardiovascular system; inhibit enzymes and cell proteins and contribute to iodine deficiency. All of these studies are available on this Study Tracker.
These include:
455 studies on the skeletal system, including 75 studies on arthritis.
294 studies on the mechanisms by which fluoride damages cells, including 155 on oxidative stress.
237 studies on the brain, including 95 studies on cognitive function.
182 studies on the kidneys, including 64 studies on the heightened risks faced by kidney patients.
Regarding neurotoxicity alone, there are now 68 published studies on fluoride – 58 involving water fluoridation – providing compelling evidence that fluoride exposure during the early years of life damages a child’s developing brain. We review 12 of these studies here; including six major Mother-Offspring studies showing the relationship between maternal fluoride ingestion and subsequent lowered IQ in their children. Four of these studies were funded by the US NIEHS (Bashash, 2017, 2018; Green, 2019 and Till, 2020) and found damage to the brain in children exposed (either at the foetal or infant stages of life) in fluoridated communities at 0.7ppm or at doses at or less than in Australia. Given the growing awareness of the damage that environmental toxins can cause to our health, together with the sharply increasing rates of chronic disease in Australia – especially neurodevelopmental and other cognitive disorders, diabetes and thyroid dysfunction – can we really afford to overlook the one toxin that is delivered to around 90 per cent of Australians every day in public water supplies and many processed foods? The full list of harms caused by the low-level, long-term ingestion of fluoridation chemicals is too extensive to cover in this article. It’s a long list because fluoride is pervasive: once in the blood stream it can reach every organ and every cell in the body. Instead we provide a summary list of the 10 major harms or health risks associated with the ingestion of this toxic, industrial waste chemical.
Ten major harms of fluoride
1. Developmental neurotoxin, other neurological damage
Fluoride is a developmental neurotoxin, that is, a chemical that can negatively affect nerve cells during brain development in utero, in babies and in children.1, 2 Toxic insults during brain development manifest as intellectual impairment (reduced IQ) and neurodevelopmental diseases such as Autism Spectrum Disorders, learning difficulties, attention-deficit hyperactivity disorder, and cognitive-behavioral issues. Twenty years of research shows that fluoridation chemicals damage the brain. In 2006, the US National Research Council (NRC) review “Fluoride in drinking water” 3, stated “it is apparent that fluorides have the ability to interfere with the functions of the brain.” In a review of the literature commissioned by the US Environmental Protection Agency (EPA), fluoride was listed among about 100 chemicals for which there is “substantial evidence of developmental neurotoxicity.”4Animal experiments also show that fluoride accumulates in the brain and alters mental behavior in a manner consistent with a neurotoxic agent. In 2014, researchers at the Harvard School of Public Health, after years of studying the neurotoxic effects chemicals such as lead and mercury, added fluoride to their burgeoning list of clinically important developmental neurotoxins, also suggesting that it may cause neurodevelopmental disabilities such as autism, ADHD, dyslexia, and other cognitive impairments. They noted that “Fluoride seems to fit in with lead, mercury, and other poisons that cause chemical brain drain. The effect of each toxicant may seem small, but the combined damage on a population scale can be serious, especially because the brain power of the next generation is crucial to all of us.”5
A total of 58 international studies have reported an association between fluoride exposure (via fluoridated water) and reduced IQ in children. One of these studies6 indicates that even just moderate levels of fluoride exposure (e.g., 0.9 ppm in the water) can exacerbate the neurological defects of iodine deficiency. None of the studies indicate an adequate margin of safety to protect all children drinking artificially fluoridated water from this affect. In 2017, a major 12-year, US$3 million, US government-funded study, referred to as the “Bashash study”7, was published showing significant reductions in children’s IQ when their mothers were exposed to fluoride during pregnancy. In this carefully controlled study of Mexican mother-offspring pairs by American and Canadian researchers, mothers were receiving the same fluoride doses as mothers in the US and Australia who live in communities that add fluoride to their water. For more details see our articles: Fluoride and reduced IQ and Fluoride is a neurotoxin
2. Endocrine disruptor, damages the thyroid gland
Fluoride is an endocrine disruptor. It has the ability to suppress thyroid hormone production, and in fact was used in the 1950s as a medication to treat an overactive thyroid gland. The 2006 NRC review reported that ingesting between .05 and 0.13 mg/kg/day of fluoride (or as low as 0.01 to .03 mg/kg/day in a person with inadequate iodine intake), decreases the production of thyroid hormone.8 Several substantial studies show that fluoridation chemicals have the potential to damage the thyroid gland. That means a 60kg Australian female, with adequate iodine intake, would need to consume only 3mg of fluoride a day to experience reduced thyroid activity. This amount of fluoride could reasonably be ingested each day from sources including fluoridated water, tea, processed foods, toothpaste and fluoride-based pesticide residue on fruit and vegetables. And that’s not including fluoride contained in various prescribed medications. A similar female with inadequate iodine intake could easily exceed the intake of 1.8mg of fluoride per day, just from drinking water alone. In 2015, a very large observational study in the UK found that in areas of high fluoridation, i.e. more than 0.7mg/L, residents are nearly twice as likely to report high hypothyroidism prevalence in comparison to non-fluoridated area.9
In 2018, the results of a case-controlled study found that fluoride impacts human thyroid hormones, especially TSH and T3, even at concentrations of less than 0.5 mg/L – below Australia’s recommended range of 0.6 to 1.1mg/litre.10 Also in 2018, the results of another very large study showed that Canadian adults who are iodine deficient and have higher fluoride exposure are at an increased risk of hypothyroidism. This is particularly relevant for us as more than 50 per cent of children and pregnant or breastfeeding women living in Australia have been shown to be iodine deficient and are at risk of developing thyroid disease. 11
For more details see our article: Fluoride and the endocrine system
3. Enzyme disruptor, damages cell proteins
Some of the earliest opponents of water fluoridation were biochemists precisely because of fluoride’s known poisonous interactions with enzymes, the proteins which act as the catalysts for around 10,000 chemical reactions in the body. In the 1950s, Dr. James Sumner, who won a Nobel Prize for his work with enzymes, said, ‘The ability for fluoride to damage enzymes has been known for more than 70 years.’
“We ought to go slowly. Everybody knows fluorine and fluorides are very poisonous substances and we use them in enzyme chemistry to poison enzymes, those vital agents in the body. That is the reason things are poisoned, because the enzymes are poisoned and that is why animals and plants die.” Today, we know that fluoride interferes with many other biochemical processes in addition to interfering with enzymes. It can influence G-proteins which are involved in the transmission of messages across membranes, and it can also interfere with hydrogen bonds which are critically important for both the structure and function of many important molecules, like proteins and nucleic acids.
4. Diabetes, damages the kidneys
Diabetes is the fastest growing chronic health condition in Australia, with around 1.7 million Australians suffering from this disease12. In 2006, the US NRC review stated, ‘Fluoride is a nephrotoxin and has the ability to at least increase the risk of diabetes.’
“The conclusion from the available studies is that sufficient fluoride exposure appears to bring about increases in blood glucose or impaired glucose tolerance in some individuals and to increase the severity of some types of diabetes. In general, impaired glucose metabolism appears to be associated with serum or plasma fluoride concentrations of about 0.1 mg/L or greater in both animals and humans.”
Diabetics are particularly susceptible to fluoride for three reasons: firstly they tend to drink more water because the kidneys require more fluid to process the higher-than-normal blood sugar levels. Therefore they generally consume substantially more fluoride from water and other sources. Secondly fluoride is a known nephrotoxin, that is a toxic agent or substance that inhibits, damages, or destroys the cells and/or tissues of the kidneys, which means diabetics are generally less capable of processing and removing the fluoride. And thirdly, fluoride is a persistent bio-accumulator which means impaired kidney function will result in higher rates of accumulation in the kidneys and other parts of the body, especially the bones and the pineal gland. It is worth noting that aboriginal and Torres Strait Islander people are almost four times more likely than non-Indigenous Australians to have diabetes or pre-diabetes, so they are especially disadvantaged by fluoridation.12
For more details, read out article: Fluoride and diabetes
5. Accumulates in and damages the pineal gland
The pineal gland is a small endocrine gland located between the two hemispheres of the brain. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns, regulates the onset of puberty in females and helps protect the body from cell damage caused by free radicals. High accumulation of fluoride occurs in the pineal gland. In 2006, The US NRC review stated, “Fluoride is likely to cause decreased melatonin production and to have other effects on normal pineal function, which in turn could contribute to a variety of effects in humans.” In the 1990s a British scientist, Jennifer Luke, discovered that fluoride accumulates in very high levels in the pineal gland.13 Animal studies have also shown that fluoride reduced melatonin levels and shortened the time to puberty.14
The pineal gland is a major target for fluoride accumulation in humans. In fact the calcified parts of the pineal gland contain the highest fluoride concentrations in the human body (up to 21,000 ppm F), higher than either bone or teeth.13,14 The soft tissue of the pineal can accumulate concentrations of around 300ppm fluoride, which could inhibit enzyme functioning.
6. Dental fluorosis, association with other systemic damage
Dental fluorosis occurs when the tooth enamel is damaged directly by fluoride intake during childhood. The effect of fluorosis ranges from a mild, barely noticeable discoloration or ‘mottling’, to serious physical damage to the tooth surface. In 2016 the results of a US National Health survey showed that adolescents with any form of fluorosis had jumped to a staggering 65 per cent. Even more concerning was the huge increase in combined moderate and severe fluorosis, from 3.7 per cent previously to a massive 30.4 per cent.
Dental fluorosis is the first obvious sign of fluoride toxicity. Despite these unequivocal results, dental fluorosis is constantly downplayed by fluoridation proponents, but nowhere more so than Australia where underhanded tactics are regularly used to hide the real effect of fluorosis. Unfortunately fluorosis is not limited to our teeth, which are often regarded as ‘biomarkers’ for our entire physiology. If fluoride is damaging our teeth – to any degree – then it can also be damaging our bones, kidneys, pineal gland and other tissues and organs. Several studies have revealed the association between dental fluorosis and other health effects. One study involving 824 Indian school children aged 8 to 15 years, revealed that dental fluorosis was significantly higher in affected (fluoridated) than control (non-fluoridated) area children. There was also a significant decrease in thyroid-stimulating hormone (TSH) in the affected area children compared to control.15
For more details, read our article: Dental fluorosis
7. Skeletal fluorosis, osteoporosis, arthritic symptoms, increased risk of hip fractures
The risk of damage to the bones from fluoride has been known for more than 70 years. Skeletal fluorosis is a condition resulting from fluoride ingestion. In a healthy person around 50 per cent of the fluoride will be expelled and the remainder will accumulate in the bones and pineal gland. The disease develops insidiously and can be difficult to distinguish from a number of other more common bone and joint diseases including osteoarthritis, renal osteodystrophy, spondylosis, DISH, Paget’s Disease, and osteopetrosis. Fluoride can cause osteoarthritis. Susceptibility to fluorosis varies significantly according to the dose and duration of exposure and the resulting skeletal manifestations and symptoms. Recent research suggests that many people — particularly heavy tea drinkers and those with kidney impairment — may unknowingly be suffering from some form of the disease. Most doctors have no knowledge of skeletal fluorosis and have difficulty diagnosing even in the crippling stages of fluorosis. Subtler forms of the disease will often elude detection. US safety standards have erroneously held that skeletal fluorosis does not occur at water fluoride levels below 8 ppm.16 Studies in India and China have repeatedly documented skeletal fluorosis at levels as low as 0.7 to 1.5 ppm fluoride.17 A recent large, high-quality Swedish study, showed that post-menopausal women consuming fluoridated water at the Australian fluoridation level of 1mg/L were 50 per cent more likely to experience hip fractures. Australia – one of the most fluoridated countries, with around 90 per cent of the population fluoridated – has one of the highest rates of hip fractures in the world.
For more details, read our article: Fluoride and osteoporosis
8. Cancer, osteosarcoma
The timeline of research into the link between fluoridation and cancer (in particular osteosarcoma, a rare form of bone cancer) is both complex and controversial. Although several studies have failed to detect an association between the two, it is relevant that none of these studies considered the risk of fluoride during specific ages and therefore specific growth stages in life. Several studies have shown an association between fluoridation chemicals and osteosarcoma. In 1991, the US National Toxicology Program conducted a study finding that fluoride-treated male rats had a dose-dependent increase in osteosarcoma.18 Several human studies since then have found an association between fluoride in drinking water and the occurrence of osteosarcoma in young males.19 One particular study that did measure the risk of fluoride at specific windows in time was the Bassin study, published in 2001, which found that boys consuming fluoridated water at age 6, 7 and 8 years had a 5-fold risk of developing osteosarcoma during their teenage years. 20 A study in 201121 claimed to refute these findings, but the study’s methods — by the authors’ own admission — were incapable of assessing the age-specific risk during the window of 6 to 8 years that Bassin identified as the critical risk period from fluoride exposure.
More details are available here.
9. Reproductive problems
In 2006, the US NRC reported that more than 50 publications since 1990 have focused on the reproductive effects of fluoride. Most of the studies used animal models, primarily rodents, and evaluated structural or functional alterations in the male reproductive tract associated with fluoride. Several human studies have reported associations between fluoride exposure and damage to the male reproductive system. Several studies report potential damage to the male reproductive system. Most notably, a scientist at the Food & Drug Administration reported in 1994 that populations in the United States with more than 3 ppm fluoride in their water had lower “total fertility rates” than populations with lower fluoride levels.22 While 3 ppm is a higher concentration than used in Australia, the total daily dosage is relevant – especially for those who drink above-average quantities of water and consume processed foods. Three studies in China and India have reported that high fluoride exposure is associated with reduced male fertility.23 The first two were not available until 2012 and therefore were not included in the 2006 NRC review. Five studies from China, India, Mexico, and Russia have also found that high-fluoride exposure is associated with reduced male testosterone levels, while a preliminary study of fluoride-exposed aluminum workers in Russia found associations between fluoride and damaged sperm.24
10. High sensitivity amongst some individuals
In the 1950s, the renowned allergist George Waldbott discovered that some individuals are hypersensitive to ingested fluoride. In a series of case reports and double-blind studies, Waldbott and other doctors found that relatively small doses of ingested fluoride, including the consumption of fluoridated water, could induce side effects that would quickly reverse after ceasing fluoride exposure.25 In 1961, consistent with Waldbott’s research, the largest ever government-funded clinical trial of fluoride supplements reported that one per cent of the children taking the 1 mg fluoride tablets exhibited hypersensitive reactions.26 If you believe you have suffered adverse reactions to fluoride, please complete this Fluoride Testimonial form.
In 1972 a double-blind study27 was conducted in the Netherlands by 10 physicians, demonstrating the same adverse symptoms as revealed in previous studies. It was found that one to five per cent of individuals in the study showed adverse symptoms. The validity of the study was subsequently upheld in court. With this evidence and various other studies showing the toxicity of fluoride, on 31 August 1976, by Royal decree, fluoridation was banned in the Netherlands. In 1979 in Australia, The Hamer Commission of Inquiry into the Fluoridation of Victorian Water Supplies received 100 statutory declarations, some with doctor’s certificates, regarding fluoride hypersensitivity. All of these stated the symptoms cleared up after switching to distilled water for drinking and cooking. The Commission never called for medical testing. In 1994, the US Physician’s Desk Reference acknowledged that some individuals are hypersensitive to fluoride: “In hypersensitive individuals, fluorides occasionally cause skin eruptions such as atopic dermatitis, eczema or urticaria. Gastric distress, headache and weakness have also been reported. These hypersensitivity reactions usually disappear promptly after discontinuation of the fluoride.” – Physician’s Desk Reference. In 1997 a Finnish study found that the rate of skin rashes in a city’s population decreased significantly within months of the city terminating its water fluoridation program. “The most frequently reported symptoms that disappeared from the time of actual to known discontinuation of fluoridation seemed to be itching and dryness of the skin.”28 Extrapolating from the Netherlands study, an estimated 160,000 to 800,000 Australians are likely to suffer from some degree of fluoride hypersensitivity. In many cases the symptoms will be minor and they will be accepted as common everyday occurrences rather than fluoride related. However, there are also cases involving progressive chronic fatigue and other debilitating symptoms.
It is remarkable that in the 70 years of this unethical and reckless practice not one health agency in any of the countries that practice water fluoridation has called for, or financed, any scientific study to investigate the possibility that some individuals are particularly sensitive to fluoride’s toxic effects. The explanation for this unscientific and irresponsible promotion of the practice is very simple and disturbing: for those who promote fluoridation it is far more important to protect this practice than to protect the health of the public. Though apparently vague and non-specific, most of the symptoms of fluoride toxicity point towards some kind of profound metabolic dysfunction and are strikingly similar to the symptoms of Hypothyroidism.”
Dental Fluorosis Medical Module, Case Study for the 4th Year Course in Ecosystem Health at UWO – University of Western Ontario, 2002
Reference notes:
- Grandjean, P. et al., March, 2014: “Neurobehavioural Effects of Developmental Toxicity,” The Lancet Neurology, Volume 13 , Issue 3 , 330 – 338
- Choi, et al., 2012: “Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis,” Environmental Health Perspectives, 120(10): 1362-1368.
- National Research Council, The National Academies Press 2006; “Fluoride in Drinking Water A Scientific Review of EPA’s Standards”, at 262.
- Mundy, W., et al., 2009: “Building a Database of Developmental Neurotoxicants: Evidence from Human and Animal Studies.”
- News Release, 2012: “Impact of Fluoride on Neurological Development in Children,” available here.
- Lin, 1991; “The relationship of a low-iodine and high fluoride environment to subclinical cretinism in Xinjiang.
- Bashash, et al September 2017; “Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-12 Years of Age in Mexico”, Environ Health Perspectives.
- National Research Council, “Fluoride in Drinking Water A Scientific Review of EPA’s Standards”, at 262
- Peckham S, et al., 2015 “Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water.”
- Kheradpisheh,Z, et al., 2018: “Impact of Drinking Water Fluoride on Human Thyroid Hormones: A Case- Control Study.”
- The Australian Thyroid Foundation web site.
- Diabetes Australia web site.
- Luke J., 2001: “Fluoride deposition in the aged human pineal gland.” Caries Res. 35(2):125-128.
- Luke J., 1997: “The Effect of Fluoride on the Physiology of the Pineal Gland.” Ph.D. Thesis. University of Surrey, Guildford.
- Khandare A.L., et al, 2017: “Dental fluorosis, nutritional status, kidney damage, and thyroid function along with bone metabolic indicators in school-going children living in fluoride-affected hilly areas of Doda district, Jammu and Kashmir, India.” In: Environmental Monitoring and Assessment.
- IOM 1997; EPA 1985
- Jolly 1968, Jolly 1973; Susheela 1993; Xu 1997; Choubisa 2001; Huang 2009
- Bucher JR, 1991: “Results and conclusions of the National Toxicology Program’s rodent carcinogenicity studies with sodium fluoride.” International Journal of Cancer.
- Bassin 2006; Cohn 1992; Hoover 1991
- Bassin EB, et al, 2006: “Age-specific Fluoride Exposure in Drinking Water and Osteosarcoma.” (United States). Cancer Causes and Control 17: 421-8.
- Kim FM, et al., 2011: “An assessment of bone fluoride and osteosarcoma.” Journal of Dental Research 90:1171-76.
- Freni, SC, 1994 “Exposure to high fluoride concentrations in drinking water is associated with decreased birth rates.” Journal of Toxicol Environ Health.
- Peizhong 1997; Hongde 1988; Neelam 1987
- Hao 2010; Ortiz 2003; Susheela 1996; Michael 1996; Tokar 1977
- Waldbott GL., 1958: “Allergic Reactions from Fluorides.” International Archives of Allergy 12: 347-355.
- Feltman & Kosel 1961: “Prenatal and postnatal ingestion of fluorides – Fourteen years of investigation – Final report.”
- Messer HH, Armstrong WD, Singer L, 1972: “Fertility impairment in mice on a low fluoride intake. Science.”;177(52):893-4
- Lamberg M, et al. 1997: “Symptoms experienced during periods of actual and supposed water fluoridation.” Community Dentistry & Oral Epidemiology 25(4):291-5.