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Obesity epidemic is underestimated in US States
Mississippi and Texas have highest rates of obesity

A new study published in the Journal of the Royal Society of Medicine has found that the level of obesity in the United States is significantly underestimated.

Obesity levels in US states have been underestimated by as much as 50 per cent over the last 15 years.

Obesity is among the leading causes of mortality and morbidity causing an estimated 2.6 million deaths worldwide each year. The US has the highest level of obesity in high-income countries.

Undertaken by researchers at Harvard University, the study presents the first unbiased trends in national and state-level obesity in the USA. It found:

• When asked about their weight and height, women tend to under-estimate their weight, while men tend to over-estimate their height, skewing population results when calculating body mass index in self-report surveys.
• In 2002, the real level of obesity among adults [over 20 years] was 28.7% for men (up from 16% in 1988) and 34.5% for women (up from 21.5% in 1988).
• Using corrected weight and height for the year 2000 – Mississippi (31%) and Texas (30%) had the highest prevalence of obesity in men. Mississippi (37%), Texas (37%), Louisiana (37%), District of Columbia (37%), Alabama (37%) and South Carolina (36%) had the highest levels of obesity in women.

“These are the first unbiased estimates of trends in obesity in the US states and the results are staggering,”

said lead researcher Dr Majid Ezzati.

“More that 35 per cent of the female population and about one third of the male population, of a number of Southern states are obese. The study clearly identifies geographical patterns of obesity with Southern states at significantly higher levels of obesity for both men and women.

“The obesity figures shown here are in addition to the percentage of the population that would be deemed overweight, so the true extent of weight health-related problems would be much higher than our findings reflect,”

he said.

In the US, weight and height data, for the nation and for individual states, are routinely gathered through the Behavioral Risk Factor Surveillance System (BRFSS), which uses self-report in telephone interviews.

The researchers examined these data against measured data from the National Health and Nutrition Examination Survey (NHANES) for two time periods, 1988 – 1994 and 1999 – 2002, to assess how reporting on the phone may increase the bias in weight and height.

The results are the first unbiased population-level comparisons produced in the US. The study has also produced the most up-to-date geographical map showing obesity levels across all US States broken down by gender.

“Obesity levels based on self-reported height and weight, the only available data at the state level, are significantly underestimated in the US, especially when they come from telephone interviews,”

said Dr Majid Ezzati.

“Overall, women under report their weight whilst young and middle-aged men over-report their height more than their female counterparts. This bias skews the results of surveillance for overweight and obesity in the US states, reported regularly by government authorities including the Centers for Disease Control and Prevention,”

he said.

An accompanying editorial in the Journal of the Royal Society of Medicine argues that weight-related public health warnings are not only for the US but the UK as well.

“While the Health Survey for England is based on measured height and weight, trends in the UK are no less worrying,”

writes Andrew Krentz from the University of Southampton.

“The proportion of adults categorized as obese increased from 13.2% of men in 1993 to 23.6% in 2004 and from 16.4% of women in 1993 to 23.8% in 2004. These figures do not tell the whole story of what has been described as the developed world’s fastest growing rate of obesity. This unenviable position is accompanied by a coronary heart disease mortality rate that is one of the highest in Western Europe.

“We can point to socio-economic and ethnic differences that might protect us to some degree from following in the USA’s footsteps. However, current evidence cautions against sitting back and viewing the revised transatlantic figures with detached complacency,”

writes Dr Krentz.

[ends]

Trends in national and state-level obesity in the USA [PDF 588k]

‘Trends in national and state-level obesity in the USA’ by M Ezzati, H Martin, S Skjold, S Vander Hoorn and CJL Murray is published in the May issue (Vol. 99) of the Journal of the Royal Society of Medicine.

JRSM is the flagship journal of the Royal Society of Medicine. It has been published continuously since 1809. Its Editor is Dr Kamran Abbasi.

The article will be available free at www.jrsm.org from early May 2006.