TCS Daily

The Mad Fatter

By Sandy Szwarc - May 20, 2005 12:00 AM

Since the CDC recently disclosed that fat people live longer than those in "normal" weight ranges, and considerably longer than thin people, those who want to control what you eat are suggesting that whether or not being fat kills you, it will make you demented.

Recently headlines across the country trumpeted: "Study Links Middle Age Obesity to Dementia." This study was published by the British Medical Journal, which made the unusual move to rush publish it online just four weeks after acceptance and before publishing it in their print edition. It was conducted by Kaiser Permanente, one of the largest U.S. health-maintenance organizations with more than 8 million members, which has collaborated with the CDC since 2002 to develop a national agenda to address the "epidemic of obesity." The culmination of their efforts was in August 2003 when they sponsored an advisory committee roundtable called "Prevention and Treatment of Overweight and Obesity: Toward a Roadmap for Advocacy and Action" with other leaders in the war on obesity such as the Robert Wood Johnson Foundation, American Association of Health Plans, HealthPartners, and the Washington Business Group on Health.

Led by Kaiser epidemiologist Rachel A. Whitmer, this study looked at patient records for 40 to 45 year olds seen in their organization between 1964 and 1973 and who were still members of their health plan in 1994. It found 713 records (about 7 percent) in which dementia had been recorded as a diagnosis.

Dementia is a progressive deterioration in brain function and cognitive skills with aging that affects up to 5 million senior citizens in the U.S. It doubles in prevalence every 5 years after age 60, so that by 85 years old, 30 to 50% of seniors are affected. It used to be called senility, but today it's known to have many different manifestations and causes, from brain abnormalities, vascular problems and infections. Diagnosing dementia is extremely imprecise, according to the Merck Manual of Geriatrics, and requires a very thorough physical evaluation to differentiate it from benign age-related memory loss. It also needs to be differentiated from a lot of treatable conditions that mimic dementia in the elderly such as depression, hypothyroidism, vitamin B 12 deficiency, over-prescription or side effects of medications, and poor oxygenation due to lung, heart or circulation problems. This study went by the codes entered into the medical billing records and offered no information as to whether these diagnoses were further evaluated or proved correct.

The researchers proceeded to plug various characteristics of these patients into their computer to create three models, looking for correlations. In the end, they found the relative risks -- chances of a relationship -- of dementia were 24% higher in underweight (BMI <18.5), 35% higher in "overweight" (BMI 25-29.9), and 74% in "obese" (BMI >30).

These numbers sound scary, but they're inconsequential for this type of population study -- a data dredge done in a computer. Only relative risks of 200% or greater have merit in these studies.

Like all computer analyses, results depend on the information the researchers choose to enter and how they put it together. Their raw data showed slightly more cases of dementia among those who were widowed or divorced, minority, of lower educational level and smokers. So, the researchers tried to control for these factors, although they don't explain how. Whitmer told reporter, Emma Ross: "We really adjusted for everything under the sun that is related to dementia."

But the study states they didn't consider dieting, weight cycling or any nutritional factors, even though "other studies have shown that several different nutritional factors are associated with dementia." They chose to overlook the most reasonable contributing factors of all, which also best explain their findings.

Consider that increased risks for dementia were found in elderly women of all weight categories but not in the men -- although the men were fatter than the women. It is therefore doubtful fat can be blamed. Women diet and "watch their figures" much more so than men and are more likely to suffer the long-term effects of dieting and nutritional shortages. They're also more likely to have the other things known to exacerbate mental decline in the elderly: be widowed, live alone with less mentally-stimulating interactions, live on lower fixed incomes and to have been smokers.

Before putting credence into this study, two additional questions need to be asked. First, does it build upon a solid body of evidence and have the findings been able to be replicated in clinical studies? In this case, the authors state: "To date, this is the first study to determine the contribution of mid-life adiposity...on risk of dementia."

Second, is there any logical explanation for how fatness might make one senile? No. Nor could the authors supply one, as they exhausted all of the possible explanations they could come up with. They stated: "The role of central obesity...on our findings is unknown." So, just like all useless links between variables -- such as wearing bras and breast cancer -- this one doesn't mean anything, either.



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