A variety of age-related diseases – including bone weakness, sexual dysfunction, diabetes, cancer and cardiovascular disease – can be predicted by a single hormone that appears at a constant level in men throughout their lives, new research reveals.
This hormone is INSL3, and it first appears during puberty. From then on, its levels only drop slightly with old age. This consistency and the young age at which it appears make INSL3 valuable to scientists – and perhaps to human health.
A person with lower INSL3 levels at a young age is also likely to have lower levels of the hormone in old age, according to the new research. If this translates to an increased risk of health complications, as the study suggests, those health risks could potentially be managed years earlier.
“Understanding why some people are more likely to develop disability and disease as they age is vital so that interventions can be found to ensure that people live not only long lives but also healthy lives as they age. they age,” says reproductive endocrinologist Ravinder Anand-Ivell. from the University of Nottingham in the UK.
“Our discovery of hormones is an important step in understanding this and will pave the way to not only help people individually, but to help alleviate the care crisis we face as a society.”
INSL3 is made by the same cells in the testes that produce testosterone; unlike testosterone, INSL3 does not fluctuate as men become adults.
To monitor the level of INSL3 in the blood, the researchers took samples from more than 2,200 men in eight different regional centers in Europe. The men’s INSL3 levels remained stable over time and also varied widely between individuals, enough to distinguish health risks.
Researchers suggest that INSL3 levels in the blood are reliably correlated with the number and health of Leydig cells in the testicles – having fewer of these cells and less testosterone has also been linked to many health problems later in life.
“Now that we know the important role this hormone plays in predicting disease and how it varies from man to man, we are turning our attention to finding the factors that have the most influence on the level of INSL3 in the blood,” says molecular endocrinologist Richard Ivell from the University of Nottingham.
“Preliminary work suggests that nutrition in early life may play a role, but many other factors such as genetics or exposure to certain environmental endocrine disruptors may play a role.”
In nine categories of morbidity that participants reported in the questionnaires, including cancer, diabetes, and cardiovascular disease, INSL3 was linked to an increased risk of morbidity in eight of them (only depression did not). not found to have a correlation in this study).
But when the researchers adjusted for other hormonal and lifestyle factors, such as BMI and smoking status, most of these associations with INSL3 were lost, except for high blood pressure and cardiovascular illnesses.
And by testing whether INSL3 levels in blood samples from a subset of men could predict health outcomes around four years later, lower hormone levels were associated with seven out of nine categories. of comorbidity. But again, that was without considering other factors.
One area that scientists want to explore in future studies is the link between INSL3 and sexual health, with its strong association with testosterone, but that was not included in detail in this particular research.
Future studies should also “focus on longer time periods to determine whether INSL3 measured in younger or middle-aged men…is truly predictive of later onset of an age-related health problem. “, conclude the researchers.
If the link between INSL3 and these health risks is established by further studies, and scientists are able to pinpoint exactly why the link exists, that means preparations can be made much earlier to try to detect – and stop – a variety of age-related health problems. problems to occur.
“The holy grail of aging research is to close the fitness gap that appears as people age,” says Anand-Ivell.
The research has been published in Frontiers in endocrinology.