Like the 400,000-deaths study, Olshansky's work essentially ignores the influence of medical progress in increasing life expectancy. Despite the enormous gains we've seen (more than six years of life expectancy since 1970), Olshansky and his co-authors write: "We believe that potential forms of technology do not justify developing or revising forecasts for life expectancy." Olshansky's theory is questionable, to say the least. Discussing their aforementioned study that found a dramatic decline in the number of deaths attributed to obesity, Flegal and her co-authors write:
" …the largest difference is due to the inclusion of the mortality data from NHANES II and NHANES III, which decreased estimates by 63% or more relative to NHANES I mortality data alone … Relative to NHANES I, the more recent data from NHANES II and NHANES III suggest the possibility that improvements in medical care, particularly for cardiovascular disease, the leading cause of death among the obese, and its risk factors may have led to a decreased association of obesity with total mortality. Cardiovascular risk factors have declined at all BMI levels in the US population, but, except for diabetes, the decline appears to be greater at higher BMI levels. These findings are consistent with the increases in life expectancy in the United States and with the declining mortality rates from ischemic heart disease. Life expectancy increased from 73.7 years in 1980 to 75.4 years in 1990 to 77.0 years in 2000 and continues to increase. Age-adjusted death rates (per 100 000 population) for ischemic heart disease declined from 345.2 in 1980 to 249.6 in 1990 to 186.6 in 2000 and continue to decline."A second JAMA paper published in April 2005 found:
Among obese persons today, prevalence of high cholesterol, high blood pressure, and smoking are now 21, 18 and 12 percentage points lower respectively, than among obese person 30 to 40 years ago … Thus, obese and overweight persons may be at lower risk of [cardiovascular disease] now than in previous eras."An article in Scientific American reports:
The new findings reinforce those published in 2001 by a 10-year WHO [World Health Organization] study that examined 140,000 people in 38 cities on four continents. The investigators, led by Alun Evans of the Queen's University of Belfast, saw broad increases in BMI and equally broad declines in high blood pressure and high cholesterol. 'These facts are hard to reconcile,' they wrote."Olshansky co-authored the study with longtime obesity doomsayer David Ludwig, who has compared the problem to a SARS outbreak that affects 60 million people. Co-author David Allison presents a number of troubling financial conflicts of interest—so many, in fact, that The New England Journal of Medicine published a three-page financial disclosure, listing more than 100 organizations (largely weight-loss companies) from which he has received money.
Despite the controversy surrounding Allison's method of determining the number of deaths attributable to obesity, the authors of the NEJM study explain that because they only wanted "plausible estimates rather than precise numbers," they chose to rely on Allison's "simpler approach." Not surprisingly, that "simpler approach" tends to exaggerate the problem.