What is a biological sign of aging

Biological Age: Massive Differences in Their Late Thirties

The biological age differs very strongly from a relatively young age. It can also be influenced. Using various markers such as kidney and lung function, US researchers determined the biological age of over 1000 38-year-olds and came up with results from under 30 to over 60 years. So far, age research has mainly focused on older people. "But if we want to prevent age-related diseases, we have to study aging in young people," said lead author Dan Belsky of Duke University in a communication published on the study.

The basis for the study, the results of which were presented in the “Proceedings” of the US National Academy of Sciences (“PNAS”), is the so-called “Dunedin Study”: As part of this ongoing long-term survey, 1,037 people were from the New Zealand city Dunedin had regular health and psychological examinations from her birth to the age of 38. The researchers developed a method with which the extent and speed of aging in young adults can be measured and compared: According to Belsky, the process of aging shows up earlier in human organs than in eyes, joints and hair.

As a result, the international research team tested 18 corresponding biomarkers, which included kidney and lung function as well as liver and immune system values. In addition, cholesterol, cardiac fitness and the length of the telomeres, the ends of chromosomes that shorten with age, were measured. The study also recorded dental health, as well as the condition of the small blood vessels behind the eye, which are considered an indicator of the condition of the blood vessels in the brain.

Using such values, the scientists calculated the biological age of the 38-year-old test subjects: It was 28 to 61 years. The researchers then compared the data with the study results of the study participants when they were 26 and 32 years old in order to be able to determine individual age processes. The result: most of the participants actually aged by a biological year every year. But some aged by three years every chronological year, while others did not age at all and remained younger than their biological age. Those whose biological age was higher than 38 years aged correspondingly faster. They also showed a greater drop in IQ, signs of an increased risk of stroke and dementia, and decreased motor skills. The traces of aging were already detectable at the age of 26, according to gerontologist Belsky.

The subjects who were biologically older also did worse in balance and coordination exercises as well as in cognitive tests. In addition, they themselves stated more often that they had physiological problems, for example when climbing stairs. The medically collected data was also supported by the external perception of the test persons: So

Duke University students used photos of 38-year-olds to estimate their ages. Those who were biologically older were also classified as older.

Overall, the scientists hope that their analysis grid will help intervene in the aging process as a whole, instead of treating individual age-related diseases in isolation. Findings from twin research, which suggest that only 20 percent of aging is genetically determined, are valuable for this. The rest is due to environmental influences. It is precisely these environmental influences that leave room for a medical influence on the aging process, the researchers write. "As we get older, our risk of various diseases increases," says Belsky. "In order to prevent several diseases at the same time and not play blind man's buff, aging itself must be our goal."

The findings of Belsky and his colleagues are particularly relevant against the background of an aging world population. In this context, the World Health Organization (WHO) has already warned of the challenges for health systems. In 2020, the proportion of those aged 60 and over will for the first time exceed the number of those under five, according to the WHO. In 2050, two billion older people can be expected, compared with 841 million today. For Germany, the Federal Statistical Office predicts that the over 65s will account for almost a third of the total population in 2050.

07/07/2015 l dpa

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