Federal representatives have long spoken out regarding the impact of the aging population in developed countries, stating that the increase in people living over the age of 65 will strain the economy and health care systems. But according to an analysis published in the BMJ, this impact has been “exaggerated” and the population is actually getting younger.

According to the US Administration on Aging, the number of older Americans increased by 18% (6.3 million) between 2000 and 2011. The UK’s Office for National Statistics states there are now more people over the age of 65 in the UK than there are children under the age of 15.

Jeroen Spijker and John MacInnes, from the University of Edinburgh in the UK, say that these statistics have concerned policy makers, as an increase in older citizens means greater demands on the economy and health care as a result of increased morbidity and disability.

In a report from the World Health Organization (WHO), an analysis of 23 low-middle income countries estimated that the economic loss from three health problems associated with the older population – heart disease, stroke and diabetes – would total $83 billion between 2006 and 2015.

But the researchers say that we should not “assume” increases in population aging will have such a detrimental impact, adding that the standard indicator of the aging population is “inaccurate.”

At present, population aging and its impact is estimated using the old age dependency ratio (OADR). This model looks at the number of people who are deemed as “dependent” (aged 65 and over) and those classed as “economically productive” (aged between 20 and 64).

The dependent population is then divided by the economically productive population, and it is estimated how many older people there are relative to the number of younger people who have to pay for them.

Explaining the “inaccuracy” of the OADR model, the researchers say it deems all people aged 65 and over as dependent, not taking into consideration their economic, social or medical circumstances.

They say that this means the model “overlooks” the fact that the increasing life expectancy means older people are now healthier and fitter, compared with older people included in previous cohorts. For example, in 1900, a 65-year-old woman in England and Wales would have an average life expectancy of 11 years, compared with 21 years today, they add.

The investigators emphasize that this factor is “crucial,” since many attitudes and behaviors, including those that are health-related, are more closely linked to life expectancy as opposed to age.

Furthermore, the study authors say that the OADR model “assumes” that everyone of working age works, even though this is not the case. They note that in Britain, there are more people who are dependent at working age than there are older people who do not work. They add that using age to define the working population “makes little sense.”

Because of these “flaws” the researchers found in the OADR, they decided to calculate the aging population using a new model – the real elderly dependency ratio.

This model uses the sum of men and women with a remaining life expectancy of up to 15 years. This number is then divided by the number of people in employment, regardless of their age.

From this, the study authors found that the number of older people classed as dependent in the UK have reduced by one-third over the past 40 years. Furthermore, they found that old age dependency is likely to stabilize at the current level, and this was the same in many other countries.

Explaining the findings from this model, the researchers say:

The economic costs of old age dependency have typically been exaggerated, especially in the UK.

Our calculations show that over the past four decades, the population, far from aging, has in fact been getting younger, with increasing numbers of people in work for every older person or child.”

The study authors note that their findings using the new ratio may have many implications for health policy and clinical practice.

“Medical staff will need to stay alert to the changing relation between ‘old’ and ‘age’ as life expectancy continues to increase and the typical onset of senescence and its associated morbidities is delayed,” they add.

“Sixty may not quite be the new 40, but expectations formed by aspiring doctors and nurses in medical school about age and morbidity or the likely health of older patients may become rapidly out of date.”

Earlier this year, Medical News Today reported that the aging process could be reversed with positive lifestyle changes, such as adopting a healthy diet and exercise, according to a study from the University of California, San Francisco.