The findings of a study led by Duke Health researchers offer a way to predict whether a person over the age of 70 has a chance of living two, five or 10 years. The markers could be obtained during a doctor’s visit, so they could be a useful guide for further clinical care. According to the researchers, the appropriate application of these measures could help determine the benefits and difficulties of screening tests and therapy in older people.
The scientists began their research at an opportune time, after gaining access to data from 1,500 blood samples from a 1980s longitudinal study of older people. The preserved samples were taken in 1992 when the participants were at least 71 years old, and then stored at the NIH. They were slated for destruction, but researchers arrived in time to transport them to Duke for analysis. The blood samples had the added advantage of being taken at a time when statin-type drugs, which could confound the results, were not yet widely used. An additional fortunate circumstance is that the participants in the mentioned study were followed for several years after their blood was drawn, while filling out questionnaires about their health histories and habits.
Taking advantage of the older study published in the journal eBioMedicine, the researchers were able to apply today’s sophisticated analytical tools to analyze the data. Thus, the researchers were able to sift through the health factors that influence longevity by identifying a core of 17 predictable variables that have a causal influence on it.
The analysis showed that the leading factor associated with longevity for each of the study’s designated ‘stations’ – two, five and 10 years after participants had their blood sample taken – was physical function, defined as the ability to buy groceries or clean the house. . Surprisingly, a diagnosis of cancer or heart disease was not among the main predictors of longevity.
In older people who lived two years after the time their blood was drawn, the leading factor associated with longevity was an abundance of high-density lipoprotein (HDL) cholesterol – not just any HDL lipids, but large amounts of very small HDL particles. This surprised scientists who had assumed that these very small HDL particles were the size best for clearing endotoxin, a powerful inflammation-causing molecule from gut microbes, from the bloodstream. [VBKMP1]. As they explain, when the particle is small it can very well pass through the depths and cracks of the cells from where it can remove the bad cholesterol, so the larger amount of such cells should [теоретски] to provide a protective benefit.
Among those who lived five years after the original blood draw, only younger age was a predictor of longevity, along with cognitive function. While among those who lived the longest, 10 years after taking the blood sample, the best indicator was smoking history, and non-smokers fared best.
The next phase of research would be to use additional analytical tools to improve predictability and identify potential targets for therapies.