INFERTILITY is the "canary in the coal mine" when there is environmental stress, Hunter researchers have found.
Researchers from the Infertility and Reproduction Program at Hunter Medical Research Institute (HMRI) have unearthed a connection between "lipid peroxidation" that occurs in both poor sperm health and in other diseases.
With 15 per cent of Australian couples seeking IVF treatment to conceive and the overall quality of sperm in decline globally over the past 40 years, researchers say that understanding what causes sub-fertility has become an "urgent matter".
University of Newcastle researcher Dr Elizabeth Bromfield said lipid peroxidation is a normal metabolic process, but can become toxic to cells under certain conditions.
Because sperm are so sensitive to their environment, they can be useful barometers of body-wide stress.
"Infertility is the canary in the coal mine," Dr Bromfield said. "It's one of the first things to be affected if there is a problem with environmental stress.
"There is also two decades of research to suggest that sub-fertile men die younger and live less healthy years so it's not just about men's ability to conceive. It's also about their overall mortality."
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Dr Bromfield said they had identified a "signature" of cell damage that connects poor sperm quality with autoimmune disease, cardiovascular disease, metabolic diseases like diabetes, cancer and urogenital diseases.
She said the next steps for her team was to further understand the role of ALOX15 - a protein involved in lipid damage - and how it may universally lead to cell damage in many diseases.
"We think pharmacological inhibitors might be able to offset that damage in the short-term," Dr Bromfield said.
Dr Bromfield, along with PhD researcher Nathan Burke, had these research findings published in the Nature Reviews Urology journal.
"What we would like to see happening is IVF clinicians directing patients towards in-depth health checks and lifestyle interventions when men aged 25 - 40 years of age are presenting with poor sperm quality," she said.
HMRI infertility and reproduction researchers say the uptake of Assisted Reproductive Technology (ART) is increasing 4.5 to 9.5 per cent each year.
They have previously told the Newcastle Herald that one-in-six couples will use ART, and that "one child in every classroom" will be conceived this way.
But because of this technology, people were not focusing on what causes male infertility nearly enough.
They said 40 per cent of infertility is caused by men, 40 per cent by women, and the cause is "unknown" in 20 per cent of cases.
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