Scientists pinpoint why women are ’50 per cent more likely’ to experience chronic pain compared to men
Chronic pain is on the rise in the UK, affecting an estimated 28million people, the majority of which are women. Now scientists finally know why.
The term is used to refer to a number of persistent conditions whereby pain lasts or recurs for more than three months.
The condition is more commonly reported in women and older people – with research suggesting around 2million more people will be suffering from chronic pain by 2040 caused by England’s ageing population.
Women are expected to bare the brunt of the burden, as evidence shows they are already around 50 per cent more likely than men to develop persistent pain.
But now experts at Michigan State University say chronic pain may not just be more commonly experienced by women – it may actually last longer.
Publishing their findings in the journal Science Immunology, the researchers concluded women experience longer-lasting pain because their immune cells are less active.
‘The difference in pain between men and women has a biological basis,’ Professor Geoffrey Laumet, physiologist and study lead author explains.
‘It’s not in your head, and you’re not soft. It’s in your immune system,’ he told women.
A major study into chronic pain reveals why women experience pain for longer
Hormone-regulated immune cells, known as monocytes, are responsible for switching off pain receptors in the body.
But according to the researchers, these cells are more active in men due to higher levels of sex hormones such as testosterone.
Women, therefore, experience longer-lasting pain and delayed recovery because their immune cells are less active, the team concluded.
They now hope to be able to manipulate these cells into producing more signals to calm pain to offer women more effective relief against chronic pain, without the need for opioids.
We feel pain when neurons, which normally lay dormant in the body, are activated by a trigger – like stubbing your toe.
But in people who suffer from chronic pain, it is thought the sensors are activated more easily – or sometimes even without an identifiable trigger.
Acute pain tends to get better over time as the body heals. But with chronic pain, the brain continues to send out pain signals long after the event.
Common chronic pain conditions include backache, joint pain, headache or migraine and endometriosis. It can also be diagnosed on its own.
Opioids like tramadol, can provide highly effective pain relief when used in the short-term. But doctors have previously warned that patients waiting months for NHS operations are taking the painkillers for dangerously long periods
Doctors have to largely rely on a patient’s account of their pain, rated on a scale from one to ten, to diagnose the condition. But, Prof Laurent says, the problem with this is that everyone experiences pain differently.
The findings come from an early-stage animal study, in which researchers noticed higher levels of a certain monocytes, called interleukin-10 in male mice.
But when they blocked male sex hormones, levels dropped, increasing pain sensitivity.
They concluded: ‘This shows that pain resolution is not a passive process. It’s an active, immune-driven one.’
The results were comparable with the psychological outcomes of people in car accidents – which Prof Sarah Linnsteadt was studying at the University of North Carolina.
She found that following an accident, men had more active interleukin-10 producing cells and recovered from pain faster than women.’
The researchers are now investigating how treatments could target this pathway to boost production of monocytes and help resolve pain faster.
‘This work opens new avenues for non-opioid therapies aimed at preventing chronic pain before it’s established,’ Prof Laurent concluded.
The findings come following alarming research last year which suggested that tramadol might not be effective as once thought at easing long-term pain.
It is one of the most commonly prescribed opioid painkillers in the UK, with hundreds of thousands of NHS prescriptions issued every month and is typically given to patients with chronic pain conditions such as arthritis or back pain.
But researchers found, after looking at 18 published studies, that while tramadol did reduce pain, the effect was not enough to make a real difference to patients symptoms.
They also found patients on the pills were nearly twice as likely to experience serious side effects including chest pain, heart disease and heart failure compared to those on placebo pills.
Patients can also become addicted to the drugs, with addiction to opioid painkillers costing the NHS around £1billion in just five years.
The Royal College of Surgeons has already warned that hundreds of thousands of patients are forced to rely on these powerful drugs to get by – as waiting lists for life-changing surgeries grow – leaving them at risk of addiction.
The NHS is now set to cancel tens of thousands of knee and hip replacement surgeries, due to a global shortage of a crucial ingredient, which could see this risk rise.
