Elevated blood protein levels predict mortality

Proteins perform a wide range of essential functions in the body and are vital for growth, development and the structure of every cell — but now scientists from the University of Surrey have revealed that proteins which play key roles in the development of diseases such as cancer and inflammation may also contribute to the risk of dying. Their findings, published in the journal PLOS One, could help clinicians identify individuals most at risk from mortality and lead to earlier medical interventions.

Using data from the UK Biobank, the scientists analysed blood protein profiles from over 38,000 middle-aged and older adults, some of whom had suffered non-accidental death, within a 5- or 10-year period after blood samples were taken. The aim of the study was to determine if the risk for early non-accidental mortality is reflected by levels of circulating blood proteins.

The study discovered 392 proteins associated with an increased risk of death within a five-year timeframe and a further 377 proteins associated with dying within 10 years, even when adjusting for health and lifestyle factors, such as smoking or pre-existing disease diagnoses. Proteins responsible for cells communicating with each other, increasing the number of cells and processes of inflammation were most predictive of mortality within five years. For example, high levels of the protein SERPINA1, responsible for protecting the lungs against certain enzymes that cause inflammation, was identified as being a strong predictor of five-year mortality.

It was also uncovered that five proteins were key indicators of mortality regardless of timeframe. This suggests these proteins play key roles in biological processes that result in conditions with poor outcomes. For example, elevated levels of SERPINA3 are associated with lower survival rates in several types of skin cancer and carcinomas.

“Certain blood proteins reflect more gradual, chronic processes that affect long-term survival whilst others are reflective of more immediate, acute health risks, like troponin for heart disease,” said lead author Natalia Koziar, a PhD candidate at the University of Surrey. “The new information could be useful to clinicians in creating a scorecard of protein levels that help to identify individuals most at risk of developing conditions with poor outcomes.”

Co-author Professor Nophar Geifman added, “Not only can different proteins reflect our overall health and help identify ongoing disease, what we have shown is that they can reflect the risk of dying within a certain period. Altered levels of such proteins are an indicator that all is not well in the body and particular life-limiting conditions could arise.

“Early identification of individuals at most risk could enable targeted interventions and treatment plans, helping to improve life span. Ultimately, this will also help our health services reduce costs, as early interventions have beneficial health economic effects by lowering the need for long-term and costly care.”

Image credit: iStock.com/Mariya Borisova