BioEd Online

Middle-aged Americans are in much worse health than their English counterparts, suggests a trans-Atlantic comparison, and scientists are at a loss to explain why.

The new study, which compared the health of white, 55 to 64-year-olds in the two countries, found that diabetes is twice as common in the United States compared with England, cancer 70% more prevalent and heart disease more than 50% more widespread.

People in the healthiest, high-income and education bracket in the United States have comparable rates of heart disease and diabetes as those in the sickest, low-income group in England, the study shows.

The differences were so great that at first "it seemed implausible", says James Smith of the RAND corporation in Santa Monica, California, and senior author of the Journal of the American Medical Association study¹. "We did not expect to find this."

The explanation doesn't seem to be down to the facts that Americans are fatter or that the British drink more alcohol, the researchers say. When they ran their health data through a model to make both groups have equivalent levels of obesity, smoking and drinking, the health differences only lessened slightly.

Instead, the difference could stem from poor childhood health or adult stress, they say. And that could serve as a caution to other countries that are increasingly adopting the eating and lifestyle patterns of the United States. "It may be a warning signal," Smith says.

Others question whether Americans are that much more sickly. Population health expert John Lynch of McGill University in Montreal, Canada, points to a study from 2003 showing that hypertension is 60% higher in Europe compared with the United States and Canada². "I'd want to look at all the evidence in total before declaring that the United States is doing all that much worse," he says.

Health complaints

To take the temperature of populations across the Atlantic, Smith and his colleagues used health information on more than 8,000 people, aged 55 to 64 years old, that had been gathered in ongoing national surveys.

The team only studied white people in order to exclude differences in health based on ethnicity. They also examined blood samples from another 7,600 people for biological markers of illness such as cholesterol and blood glucose.

The rate of self-reported health complaints in the surveys matched up with the levels that would be diagnosed based on the biological markers, the authors say. So any differences noted from the surveys cannot be explained away by the idea that Americans complain more of health problems.

And they could not pin the blame on poorer access to health care in the United States compared with the UK's national health system, because those Americans with the highest income and good, private insurance were still sicker than their English equivalents. "All the easy answers are not what is going on," Smith says. "It's something more fundamental."

Stressed out

One possible explanation is that obesity over a long time period may take more of a toll on health than the researchers could account for; their study didn't take into account how long someone had been overweight.

The Americans may have had poorer health as babies or children that destined them to sickness as adults. Or Americans could be more stressed out; stress is known to boost the risk of many major killers.

If researchers can figure out the underlying causes, then this might help them to tackle and eliminate the differences, perhaps by improving childhood health. "The United States should be able to achieve the health of the English," Smith says. "It's not an impossible goal."

Visit our newsblog to read and post comments about this story.