Number crunching: At what ages are people getting old?

Life, they say, begins at 40.

And by 44, you are already old, according to a new study. Or perhaps 60, if you are lucky.

The study, co-authored by researchers from Stanford University and Nanyang Technological University in Singapore, radically challenges the commonly held belief that human ageing happens gradually.

The new study proposes the theory that ageing occurs in two sudden bursts, around the ages of 44 and 60.

Though ‘gerontology’ – the study of old age and the process of ageing – has taken off in recent times with advancements in science and technology, the subject has fascinated mankind for a long time.

Ancient Greek philosopher Plato believed that old age brings freedom from youthful worldly desires and distractions, while Aristotle "detested old age as a natural decline that was both physical and moral".

The new study, published in the journal ‘Nature Aging’, however, looks at the issue from just a physical point of view, tracking hundreds of thousands of molecules in the test subjects—108 people aged between 25 and 75.

“We’re not just changing gradually over time...It turns out the mid-40s is a time of dramatic change, as is the early 60s,” Prof Michael Snyder, senior author of the study and director of the Center for Genomics and Personalized Medicine at Stanford University, was quoted as saying.

The study, however, does not say why the ages of 44 and 60 could be significant markers in the ageing process but the authors plan further research to bring more clarity to their work.

Non-linear changes

The study confirms unrelated previous research, which indicated that humans are not ageing in a gradual manner.

“Although many studies have explored linear changes during ageing, the prevalence of ageing-related diseases and mortality risk accelerates after specific time points, indicating the importance of studying nonlinear molecular changes,” wrote the seven co-authors in their article.

“The analysis revealed consistent nonlinear patterns in molecular markers of ageing, with substantial dysregulation occurring at two major periods occurring at approximately 44 years and 60 years of chronological age,” the authors said.

Besides 44 and 60, the US-Singapore joint project also suggested that other ages, like 55, are also important.

Many scholars working on geriatric models call these non-linear patterns “waves” of ageing. Previous research had found that humans face another “wave” when they reach 75.

Tips to patients and medics

Recent research findings, along with previous studies, can help both patients and medics treat different illnesses more carefully, taking into consideration the fact that people might be much more vulnerable to various diseases and health issues in certain ages like 44, 55, 60 and 75.

The study’s authors “identified certain modules in the clusters that suggest a nonlinear increase in several disease risks” in ages when people are getting older more quickly than other times, according to the paper.

After the age of 60 years, the findings show, people might have “a nonlinear escalation” in relation to the risk of cardiovascular, kidney diseases and Type 2 diabetes (T2D), which is formerly known as adult-onset diabetes, a form of diabetes.

Researchers have advised that people in their 60s need to consume a lot of water to fasten the functioning of organs in their bodies, which particularly helps kidneys function better, bringing essential immunity against diseases.

The participants were sampled every 3–6 months while healthy and had diverse ethnic backgrounds, the study added.

Think about 55 twice!

A number of previous studies have suggested that female ageing might be connected with menopause, which usually happens when women reach ages between 45 and 55. But the California-based research found that this is “surprisingly” the case not only for females but also for males.

“This suggests that the transition point observed at approximately 55 years of age is not solely attributed to female menopause but, rather, represents a common phenomenon in the ageing process of both sexes,” the research paper said.

“This result is consistent with previous studies, further supporting the notion that this transition point is a major characteristic feature of human aging,” it added.