Middle-aged women with toxic friendships are more likely to break their bones, scientists claim.
The stress of negative relationships causes the skeleton to reduce in density over time, leading to a higher chance of fracture, according to a study.
More than 11,000 women who had been through the menopause rated various aspects of the their social lives on a scale.
Six years later, those who were stressed out by negative friendships were more likely to have weakened bones, particularly around the hip, spine and thigh.
Scientists blamed a change in women’s hormones, including cortisol – known as the stress hormone, for the reduction in bone density.
Middle-aged women with toxic friendships are more likely to break their bones, scientists at University of Arizona have said on the back of study findings
Psychosocial, which refers to the emotional and physiological reactions that happen when someone has to deal with stressful situations beyond their ability to cope, is a well-established risk factor in many chronic diseases.
It could be caused by marital problems, financial crisis and the death of a loved one.
But the role of psychosocial stress in bone loss is lacking in research – until now.
The team from the Department of Epidemiology and Biostatistics, University of Arizona, used data from a long term US study that launched in 1993.
The Women’s Health Initiative collected data on women’s bone mineral density (BMD) at enrollment and at a follow up visit six years later.
Low bone density, which weakens the bones, puts a person at a greater risk of fractures as well as condition such as osteoporosis – which affects over three million people in the UK and ten million in the US.
A questionnaire at enrollment asked women to rate psychosocial stress caused by their social lives, particularly the strain of negative relationships and how much support they received from friends.
The women who rated their social lives the most stressful had lower bone density at the six-year follow up, according to findings published in the Journal of Epidemiology & Community Health.
The biggest reductions were recorded at the hip, lower back, known as the lumbar spine, and femoral neck, which is at the top of the thigh bone.
With every added point on a stress scale of one to 20, the BMD dropped a small per cent.
This was after taking potential influencing factors, including age, weight (BMI), smoking status, alcohol use, hormone therapy use and physical activity into account.
The team suggest psychosocial stress reduces the release of hormones that affect the strength of bones, including cortisol, glucocorticoids, growth hormone and cytokines.
Lead author Shawna Follis, a research assistant, said: ‘This is an observational study, and as such, can’t establish cause.
‘Psychosocial stress levels may have been lower than average because participants in the Women’s Health Initiative were healthy individuals living in the community.
‘What’s more, psychosocial stress levels were self-reported at the start of the study and may have changed over the follow-up period.
‘However we found that bone loss is among the physiological stress responses more strongly related to the quality of social relationships than quantity.
‘In agreement with the prior literature, the findings for social strain and social functioning suggest that poor quality of social relationships may be associated with bone loss in postmenopausal women.’
The finding build on research such as that by the University of California, published in 2014, that found a poor marriage – but not marital status – also lowers BMD in women.
The NHS states women can lose up to 20 per cent of their bone density in the five to seven years after the menopause due to falling levels of the female hormone oestrogen.