Thinking Like a Scientist

Transcription

1 XKCD.com

2 Thinking Like a Scientist Carlos Aizenman Dept. of Neuroscience Brown University ARISE Professional Learning Community Conference, 2012

3 Why is science literacy important? Understanding world around us Making informed opinions about current issues: stem cells, climate change, vaccines, teaching of evolution, GMOs Content knowledge is important. But... Critical thinking skills are most important: Think like a scientist!

4 XKCD.com

5 Scientists use the scientific method: 1. Here s a hypothesis 2. This is what I d expect to happen if it s true, or this is what would happen if it weren t true. 3. These are the experiments and controls we did and what we actually observed 4. In light of these results, this is what can be said about the hypothesis 5. This is what we re going to do next to prove or disprove it.

6 But how can you use this every day? Each day we are bombarded with bucketloads of medical and scientific claims

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10 How do you make sense of all this?!? Think like a scientist!! Be a skeptic.

11 Is the claim based on science or pseudoscience? Science Based on scientific method: falsifiable, controlled, ideally double blind Peer reviewed Based on our current scientific understanding Pseudoscience (a.k.a Woo ) Based on shaky scientific foundations Anecdotal evidence/ testimonials Claims of exclusivity and conspiracy theories Snake oil salesman

12 Pseudoscience is based on shaky scientific foundations Homeopathy: Like cures like, serial dilutions and water memory Reiki: Palm healing, transferring of universal energy, or ki, through the palms to promote healing Both proven to be ineffective. (other than a placebo effect)

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14 Pseudoscience sometimes sounds scientific...use holographic technology to "resonate with and respond to the natural energy field of the body", and increase sporting ability.

15 Some pseudoscientific claims can be loosely based on actual science, but distort or misrepresent the evidence. Chiropractic, Acupuncture, Special Diets/Nutritional Supplementation Some evidence that they may be effective for ameliorating certain conditions, and plausible biological explanations.

16 But often originate from dubious pseudoscientific theoretical foundations: body meridians and flow of qi, vertebral subluxations and body s innate intelligence, detoxification or de-acidification of the body And often exaggerate ability to treat multiple conditions.

17 Chiropractic treatment of neurological disorders

18 CASE STUDY Reduction of Motor and Vocal Tics in a Female Undergoing Chiropractic Care to Reduce Vertebral Subluxation Pamela A. Stone-McCoy BS, DC, CACCP Bio Kim Muhlenkamp BS, DC. Bio Journal of Pediatric, Maternal & Family Health - Chiropractic ~ Volume 2009 ~ Issue 3 ~ Pages 1-6

19 Chiropractic neck manipulation and stroke Reuter, U., Hämling, M., Kavuk, I., Einhäupl, K., Schielke, E., &,. (2006). Vertebral artery dissections after chiropractic neck manipulation in Germany over three years Journal of Neurology, 253 (6), DOI: /s x Norris JW, Beletsky V, & Nadareishvili ZG (2000). Sudden neck movement and cervical artery dissection. The Canadian Stroke Consortium. CMAJ : Canadian Medical Association journal = journal de l Association medicale canadienne, 163 (1), PMID: Rothwell DM, Bondy SJ, & Williams JI (2001). Chiropractic manipulation and stroke: a population-based case-control study. Stroke; a journal of cerebral circulation, 32 (5), PMID: /100,000

20 Does vitamin C help fight colds? AIRBORNE PLEDGE: AIRBORNE was developed by a school teacher who was sick of catching colds in class.* The natural ingredients in AIRBORNE'S unique formulation, reflects [sic] state of the art antioxidant, electrolyte and herbal technology. WE PLEDGE to our customers to continually upgrade the AIRBORNE formula as improved technology avails itself, thereby offering the finest most effective health formula possible. Satisfaction guaranteed. DIRECTIONS: AT THE FIRST SIGN OF A COLD SYMPTOM, SIMPLY DROP (1) AIRBORNE TABLET IN A SMALL AMOUNT OF PLAIN WATER, LET DISSOLVE ABOUT (1) MINUTE AND DRINK.* REPEAT EVERY THREE HOURS AS NECESSARY.* EFFERVESCENT TECHNOLOGY OFFERS 100% IMMEDIATE ABSORPTION! *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

21 Vitamin C for preventing and treating the common cold. Douglas RM, Hemilä H, Chalker E, Treacy B. Cochrane Database Syst Rev Jul 18;(3):CD Thirty trial comparisons involving 11,350 study participants contributed to the meta-analysis on the relative risk (RR) of developing a cold whilst taking prophylactic vitamin C. The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine megadose prophylaxis is not rationally justified for community use.

22 But where it gets really tricky, is learning to spot bad science, or science that is oversold or misrepresented

23 by Emily Willingham, Double X Science

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29 Milk depletes the calcium from your bones The milk myth has spread around the world based on the flawed belief that this protein and calcium-rich drink is essential to support good overall health and bone health in particular at any age. It is easy to understand that the confusion about milk s imaginary benefits stems from the fact that it contains calcium around 300 mg per cup. But many scientific studies have shown an assortment of detrimental health effects directly linked to milk consumption. And the most surprising link is that not only do we barely absorb the calcium in cow s milk (especially if pasteurized), but to make matters worse, it actually increases calcium loss from the bones. What an irony this is! Here s how it happens. Like all animal protein, milk acidifies the body ph which in turn triggers a biological correction. You see, calcium is an excellent acid neutralizer and the biggest storage of calcium in the body is you guessed it in the bones. So the very same calcium that our bones need to stay strong is utilized to neutralize the acidifying effect of milk. Once calcium is pulled out of the bones, it leaves the body via the urine, so that the surprising net result after this is an actual calcium deficit.!!

30 Scientific studies show that milk increases fracture risk Many scientific studies contradict the conventional wisdom that milk and dairy consumption help reduce osteoporotic fractures. Surprisingly, studies demonstrating that milk and dairy products actually fail to protect bones from fractures outnumber studies that prove otherwise. Even drinking milk from a young age does not protect against future fracture risk but actually increases it. Shattering the savings account calcium theory, Cumming and Klineberg report their study findings as follows: Consumption of dairy products, particularly at age 20 years, was associated with an increased risk of hip fracture in old age. ( Case-Control Study of Risk Factors for Hip Fractures in the Elderly. American Journal of Epidemiology. Vol. 139, No. 5, 1994). And the 12 year long Harvard Nurses Health Study found that those who consumed the most calcium from dairy foods broke more bones than those who rarely drank milk. This is a broad study based on 77,761 women aged 34 through 59 years of age. In the authors own words: These data do not support the hypothesis that higher consumption of milk or other food sources of calcium by adult women protects against hip or forearm fractures. (Source: Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. American Journal of Public Health. 1997).

31 Dairy foods and bone health: examination of the evidence1, 2 1. Roland L Weinsier and Carlos L Krumdieck Author Affiliations From the Department of Nutrition Sciences, University of Alabama at Birmingham. Next Section Abstract It is unclear whether dairy foods promote bone health in all populations and whether all dairy foods are equally beneficial. The objective of this review was to determine whether scientific evidence supports the recommendation that dairy foods be consumed daily for improved bone health in the general US population. Studies were reviewed that examined the relation of dairy foods to bone health in all age, sex, and race groups. Outcomes were classified according to the strength of the evidence by using a priori guidelines and were categorized as favorable, unfavorable, or not statistically significant. Of 57 outcomes of the effects of dairy foods on bone health, 53% were not significant, 42% were favorable, and 5% were unfavorable. Of 21 stronger-evidence studies, 57% were not significant, 29% were favorable, and 14% were unfavorable. The overall ratio of favorable to unfavorable effects in the stronger studies was 2.0 (4.0 in <30-y-olds, 1.0 in y-olds, and 1.0 in >50-y-olds). Males and ethnic minorities were severely underrepresented. Dairy foods varied widely in their content of nutrients known to affect calcium excretion and skeletal mass. Foods such as milk and yogurt are likely to be beneficial; others, such as cottage cheese, may adversely affect bone health. Of the few stronger-evidence studies of dairy foods and bone health, most had outcomes that were not significant. However, white women <30 y old are most likely to benefit. There are too few studies in males and minority ethnic groups to determine whether dairy foods promote bone health in most of the US population.

32 Do vaccines cause autism?

33 Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Wakefield AJ, Murch SH, Anthony A, Linnell J, Casson DM, Malik M, Berelowitz M, Dhillon AP, Thomson MA, Harvey P, Valentine A, Davies SE, Walker-Smith JA. Source Inflammatory Bowel Disease Study Group, University Department of Medicine, Royal Free Hospital and School of Medicine, London, UK. Abstract BACKGROUND: We investigated a consecutive series of children with chronic enterocolitis and regressive developmental disorder. METHODS: 12 children (mean age 6 years [range 3-10], 11 boys) were referred to a paediatric gastroenterology unit with a history of normal development followed by loss of acquired skills, including language, together with diarrhoea and abdominal pain. Children underwent gastroenterological, neurological, and developmental assessment and review of developmental records. Ileocolonoscopy and biopsy sampling, magnetic-resonance imaging (MRI), electroencephalography (EEG), and lumbar puncture were done under sedation. Barium follow-through radiography was done where possible. Biochemical, haematological, and immunological profiles were examined. FINDINGS: Onset of behavioural symptoms was associated, by the parents, with measles, mumps, and rubella vaccination in eight of the 12 children, with measles infection in one child, and otitis media in another. All 12 children had intestinal abnormalities, ranging from lymphoid nodular hyperplasia to aphthoid ulceration. Histology showed patchy chronic inflammation in the colon in 11 children and reactive ileal lymphoid hyperplasia in seven, but no granulomas. Behavioural disorders included autism (nine), disintegrative psychosis (one), and possible postviral or vaccinal encephalitis (two). There were no focal neurological abnormalities and MRI and EEG tests were normal. Abnormal laboratory results were significantly raised urinary methylmalonic acid compared with age-matched controls (p=0.003), low haemoglobin in four children, and a low serum IgA in four children. INTERPRETATION: We identified associated gastrointestinal disease and developmental regression in a group of previously normal children, which was generally associated in time with possible environmental triggers.

34 Wakefield paper, together with perceived increase in reported cases of autism during the 90 s, coinciding with revised immunization schedules, led to dramatic drops in immunization in Europe and the USA. Special interest groups like Autism One claiming to represent rights of autistic individuals and their families began to peddle anti-vaccine propaganda and pseudoscientific treatments to reverse vaccine damage. Outbreaks of measles and mumps in UK, Europe and in the USA

35 But what was the evidence? Following the initial claims in 1998, multiple large epidemiological studies were undertaken. Reviews of the evidence by the Centers for Disease Control and Prevention, the American Academy of Pediatrics, the Institute of Medicine of the US National Academy of Sciences, the UK National Health Service, and the Cochrane Library all found no link between the vaccine and autism. Source:Wikipedia

36 Wakefield study retracted in 2010 due to conflicts of interest and data manipulation Yet the controversy still persists!

37 Resources Science Based Medicine: Quackwatch: What s the Harm: James Randi Educational Foundation: NeuroLogica: Respectful Insolence: National Institutes of Health, CDC, NSF Websites Science Blogs: Double X Science, Scientific American Blogs, Discover Blogs, Wired Blogs, etc. PubMed Google is your friend!