Katherine Flegal

Last updated
Katherine M. Flegal
NationalityAmerican
Alma mater University of California, Berkeley, Cornell University, University of Pittsburgh
Known forObesity research
Scientific career
Fields Epidemiology
Institutions Centers for Disease Control
Thesis Anthropometric evaluation of obesity in epidemiologic research on risk factors: blood pressure and obesity in the health examination survey  (1982)
Doctoral advisor Jere Haas [1]

Katherine Mayhew Flegal is an American epidemiologist and senior scientist at the Centers for Disease Control and Prevention's National Center for Health Statistics. She is one of the most highly cited scientists in the field of the epidemiology of obesity according to Thomson Reuters [2] and has been called "one of the great epidemiologists" by former FDA Commissioner David A. Kessler. [3]

Contents

Education and career

Flegal was born in Berkeley, California, where she grew up. [1] She earned a bachelor's degree in anthropology from the University of California, Berkeley (UC) in 1967 and lived in Turkey for 7 months. Following that she had a job as a programmer trainee at the Alameda County Data Processing Center and became responsible for its food stamp program. This gave her extensive experience in data management, coding, and record keeping. After three years and some community college courses in chemistry and biology, Flegal returned to UC to earn a second bachelor’s degree, in food and nutrition. [1]

Next Flegal completed Master's and Ph.D. degrees at Cornell University, expanding her interests in statistics and epidemiology and receiving her Ph.D. in 1982. When a post-doctoral position at the University of Pittsburgh offered little opportunity for research, Flegal completed a second master's degree there, in public health (MPH). [1] [4] In 1987, after working at the University of Michigan's biostatistics department, Flegal began working at the Centers for Disease Control (CDC). [4] [1]

Research

Flegal is well known for a series of influential and highly cited articles on the prevalence of obesity in U.S. children and adults. [2] [5] In 1994, Flegal and her CDC co-authors were among the first to publish data indicating that the percentage of overweight people in the United States had been increasing from the 1980s onwards. Their paper appeared in the Journal of the American Medical Association (JAMA). [6] [7] In addition, she was a major contributor to the development of the 2000 CDC growth charts, used in the U.S. to assess the growth patterns of infants and children. [8] [6]

In 2005 Flegal and co-authors from CDC and NIH published a study in JAMA which found that being overweight was associated with lower mortality than normal weight and that obesity was associated with slightly higher mortality. [9] The study received considerable opposition, in part because its conclusions differed from those of another paper published by senior CDC authors in March 2004. [1] After considerable discussion, [10] [11] the CDC accepted Flegal's figures as correct. [12] Flegal herself has stated "Our paper was straightforward and defensible, used only publicly available data, and corrected the errors in several previous papers on the topic". [1] Flegal's article received CDC's highest science award, the Charles C. Shepard award, in 2006. [12]

In 2013, Flegal was the lead author of a systematic review and meta-analysis published in JAMA regarding the association of overweight and obesity with mortality. In a large sample, drawn from other countries as well as the U.S., overweight people had lower mortality relative to people of normal weight. The work examined the results of 97 studies that had included 2.88 million people. [13] [14]

I think that when you find a result that you don’t expect, the interesting thing ought to be, how can we look into this in a different way? Not just to say that this is giving the wrong message so it should be suppressed. Because that’s not really science, in my opinion. - Katherine Flegal, 2022 [6]

Reaction

Flegal's work has been criticized by Walter Willett of the Harvard School of Public Health, who called her 2013 meta-analysis paper a "pile of rubbish ... No one should waste their time reading it." [5] Willett was subsequently admonished for his unseemly behavior towards Flegal in an editorial and feature article in Nature , one of the world's pre-eminent scientific journals. [15]

Jeffrey Scott Flier, the dean of Harvard Medical School, convened a panel of experts to discuss the paper at Harvard on February 20, 2013. The panel's members suggested that Flegal's meta-analysis paper contained methodological errors, and criticized the selection criteria used for washing out too many people. [16] Harvard's own subsequent analysis supported its position, but also received criticisms over how the researchers determined who to include. [13]

Many researchers accept the results of Flegal's 2005 and 2013 papers and see them as an illustration of what is known as the "obesity paradox". [5] [17] In 2021, Diana Thomas described Flegal's 2013 meta-analysis as "the gold standard" of obesity research. [17]

In 2021, Flegal published a paper about her experiences with her 2005 and 2013 papers, concluding "Scientific findings should be evaluated on their merits, not on the basis of whether they fit a desired narrative." [18]

Related Research Articles

<span class="mw-page-title-main">Body mass index</span> Relative weight based on mass and height

Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms (kg) and height in metres (m).

Dieting is the practice of eating food in a regulated way to decrease, maintain, or increase body weight, or to prevent and treat diseases such as diabetes and obesity. As weight loss depends on calorie intake, different kinds of calorie-reduced diets, such as those emphasising particular macronutrients, have been shown to be no more effective than one another. As weight regain is common, diet success is best predicted by long-term adherence. Regardless, the outcome of a diet can vary widely depending on the individual.

<span class="mw-page-title-main">Obesity</span> Medical condition in which excess body fat harms health

Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it can potentially have negative affects on health. People are classified as obese when their body mass index (BMI)—a person's weight divided by the square of the person's height—is over 30 kg/m2; the range 25–30 kg/m2 is defined as overweight. Some East Asian countries use lower values to calculate obesity. Obesity is a major cause of disability and is correlated with various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis.

<span class="mw-page-title-main">Mediterranean diet</span> Diet inspired by the Mediterranean region

The Mediterranean diet is a diet inspired by the eating habits and traditional food typical of southern Spain, southern Italy, and Crete, and formulated in the early 1960s. It is distinct from Mediterranean cuisine, which covers the actual cuisines of the Mediterranean countries. While inspired by a specific time and place, the "Mediterranean diet" was later refined based on the results of multiple scientific studies.

Bariatrics is the branch of medicine that deals with the causes, prevention, and treatment of obesity.

<span class="mw-page-title-main">Sedentary lifestyle</span> Type of lifestyle involving little or no physical activity

Sedentary lifestyle is a lifestyle type, in which one is physically inactive and does little or no physical movement and or exercise. A person living a sedentary lifestyle is often sitting or lying down while engaged in an activity like socializing, watching TV, playing video games, reading or using a mobile phone or computer for much of the day. A sedentary lifestyle contributes to poor health quality, diseases as well as many preventable causes of death.

<span class="mw-page-title-main">Childhood obesity</span> Obesity in children

Childhood obesity is a condition where excess body fat negatively affects a child's health or well-being. As methods to determine body fat directly are difficult, the diagnosis of obesity is often based on BMI. Due to the rising prevalence of obesity in children and its many adverse health effects it is being recognized as a serious public health concern. The term overweight rather than obese is often used when discussing childhood obesity, as it is less stigmatizing, although the term overweight can also refer to a different BMI category. The prevalence of childhood obesity is known to differ by sex and gender.

<span class="mw-page-title-main">Walter Willett</span> American nutritionist

Walter C. Willett is an American physician and nutrition researcher. He is the Fredrick John Stare Professor of Epidemiology and Nutrition at the Harvard School of Public Health and was the chair of its department of nutrition from 1991 to 2017. He is also a professor of medicine at Harvard Medical School.

The obesity paradox is the finding in some studies of a lower mortality rate for overweight or obese people within certain subpopulations. The paradox has been observed in people with cardiovascular disease and cancer. Explanations for the paradox range from excess weight being protective to the statistical association being caused by methodological flaws such as confounding, detection bias, reverse causality, or selection bias.

<span class="mw-page-title-main">Obesity in the United States</span> Overview of obesity in the United States of America

Obesity is common in the United States and is a major health issue associated with numerous diseases, specifically an increased risk of certain types of cancer, coronary artery disease, type 2 diabetes, stroke, and cardiovascular disease, as well as significant increases in early mortality and economic costs.

<span class="mw-page-title-main">Overweight</span> Above a weight considered healthy

Being overweight or fat is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.

Intermittent fasting is any of various meal timing schedules that cycle between voluntary fasting and non-fasting over a given period. Methods of intermittent fasting include alternate-day fasting, periodic fasting such as the 5:2 diet, and daily time-restricted eating (TRE).

<span class="mw-page-title-main">Preventable causes of death</span> Causes of death that could have been avoided

Preventable causes of death are causes of death related to risk factors which could have been avoided. The World Health Organization has traditionally classified death according to the primary type of disease or injury. However, causes of death may also be classified in terms of preventable risk factors—such as smoking, unhealthy diet, sexual behavior, and reckless driving—which contribute to a number of different diseases. Such risk factors are usually not recorded directly on death certificates, although they are acknowledged in medical reports.

<span class="mw-page-title-main">Obesity-associated morbidity</span> Medical condition

Obesity is a risk factor for many chronic physical and mental illnesses.

<span class="mw-page-title-main">Epidemiology of obesity</span> Recognition of obesity as an epidemic

Obesity has been observed throughout human history. Many early depictions of the human form in art and sculpture appear obese. However, it was not until the 20th century that obesity became common — so much so that, in 1997, the World Health Organization (WHO) formally recognized obesity as a global epidemic and estimated that the worldwide prevalence of obesity has nearly tripled since 1975. Obesity is defined as having a body mass index (BMI) greater than or equal to 30 kg/m2, and in June 2013 the American Medical Association classified it as a disease.

<span class="mw-page-title-main">Classification of obesity</span> Overview of the classification of the condition of obesity

Obesity classification is a ranking of obesity, the medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. The World Health Organization (WHO) classifies obesity by body mass index (BMI). BMI is further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. In children, a healthy weight varies with age and sex, and obesity determination is in relation to a historical normal group.

Management of obesity can include lifestyle changes, medications, or surgery. Although many studies have sought effective interventions, there is currently no evidence-based, well-defined, and efficient intervention to prevent obesity.

<span class="mw-page-title-main">Frank Hu</span> Nutrition researcher

Frank B. Hu is a Chinese American nutrition and diabetes researcher. He is Chair of the Department of Nutrition and the Fredrick J. Stare Professor of Nutrition and Epidemiology at the Harvard T.H. Chan School of Public Health, and Professor of Medicine at the Harvard Medical School.

Normal weight obesity is the condition of having normal body weight, but with a high body fat percentage, leading to some of the same health risks as obesity.

Leann L. Birch was an American developmental psychologist, best known for her research on children's eating behaviors.

References

  1. 1 2 3 4 5 6 7 Flegal, Katherine M. (August 21, 2022). "A Female Career in Research". Annual Review of Nutrition. 42 (1): annurev–nutr–062220-103411. doi: 10.1146/annurev-nutr-062220-103411 . ISSN   0199-9885. PMID   35363538. S2CID   247866328 . Retrieved April 22, 2022.
  2. 1 2 Katherine Flegal Interview
  3. ↑ "Former FDA Commissioner David Kessler: "The End of Overeating: Taking Control of the Insatiable American Appetite"". Democracy Now!. August 3, 2009. Retrieved April 22, 2022.
  4. 1 2 Bartoshuk, Linda (January 10, 2010). "The "Obesity Epidemic": An Interview with Katherine Flegal". Observer. 23 (1). Retrieved December 25, 2014.
  5. 1 2 3 Hughes, Virginia (May 22, 2013). "The big fat truth". Nature. 497 (7450): 428–430. Bibcode:2013Natur.497..428H. doi: 10.1038/497428a . PMID   23698426. S2CID   4407621.
  6. 1 2 3 Callahan, Alice (September 8, 2022). "She saw the obesity epidemic coming. Then an unexpected finding mired her in controversy". Knowable Magazine. Annual Reviews. doi: 10.1146/knowable-090822-1 . Retrieved September 9, 2022.
  7. ↑ Kuczmarski, Robert J.; Flegal, Katherine; Campbell, Stephen M.; Johnson, Clifford L. (July 20, 1994). "Increasing Prevalence of Overweight Among U.S. Adults: The National Health and Nutrition Examination Surveys, 1960 to 1991". JAMA. 272 (3): 205–211. doi:10.1001/jama.1994.03520030047027. PMID   8022039 . Retrieved September 9, 2022.
  8. ↑ Dawson, Peter (May 2002). "Revised Growth Charts for Children". American Family Physician. 65 (9): 1941–1942. PMID   12018814.
  9. ↑ Flegal, KM; Graubard, BI; Williamson, DF; Gail, MH (April 20, 2005). "Excess deaths associated with underweight, overweight, and obesity". JAMA. 293 (15): 1861–7. doi:10.1001/jama.293.15.1861. PMID   15840860.
  10. ↑ Kolata, Gina. Rethinking Thin, The New Science of Weight Loss – and the Myths and Realities of Dieting (2007), 201-208.
  11. ↑ Lassek, William D. and Steven J.C. Gaulin. Why Women Need Fat (2012), 96-101
  12. 1 2 "2021 Charles C. Shepard Science Awards" (PDF). CDC. October 20, 2021. Retrieved April 22, 2022.
  13. 1 2 Khazan, Olga (August 14, 2017). "Why Scientists Can't Agree on Whether It's Unhealthy to Be Overweight". The Atlantic. Retrieved April 22, 2022.
  14. ↑ Flegal, Katherine M.; Kit, Brian K.; Orpana, Heather; Graubard, Barry I. (January 2, 2013). "Association of All-Cause Mortality With Overweight and Obesity Using Standard Body Mass Index Categories". JAMA. 309 (1): 71–82. doi:10.1001/jama.2012.113905. PMC   4855514 . PMID   23280227.
  15. ↑ "Shades of grey". Nature. 497 (7450): 410. May 22, 2013. doi: 10.1038/497410a .
  16. ↑ Miller, Jake (February 23, 2013). "Weight and mortality". Harvard Gazette. Retrieved December 25, 2014.
  17. 1 2 Crawford, Amy Crawford (July 16, 2021). "The obesity research that blew up - The Boston Globe". Boston Globe. Retrieved April 22, 2022.
  18. ↑ Flegal, Katherine M. (July–August 2021). "The obesity wars and the education of a researcher". Progress in Cardiovascular Diseases. 67: 75–79. doi:10.1016/j.pcad.2021.06.009. PMID   34139265. S2CID   235470848.
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