Toxic relationships really can be as bad for women's health as obesity, physical inactivity or overindulging in alcohol, a study has found.

According to the University of Queensland study, the secret to health and wellbeing could be a quality relationship.

Lead author Dr Xiaolin Xu found unsatisfying social relationships can be a health risk factor, but women who find quality relationships in their 40s and 50s are less likely to develop multiple chronic conditions in older age.

"There is a known link between poor social relationships and poor health, but until now, the research had focused on individual diseases or factors like a person's marital status or the size of their social network," Dr Xu said.

"In reality, our lives are more complex - people accumulate health conditions as they age, and it's possible to be married or have a big social network and still be deeply unhappy."

The UQ study examined the effect of relationship satisfaction on women's long-term health and the risk of developing multiple health conditions.

Using data from 7694 participants in the Australian Longitudinal Study on Women's Health aged 45-50 in 1996, the study tracked health and wellbeing every three years up to 2016.

Participants rated their level of satisfaction in their relationships with partners, family, friends and colleagues.

The health participants were also monitored for diabetes, hypertension, heart disease, stroke, chronic obstructive pulmonary disease, asthma, osteoporosis, arthritis, cancer, depression and anxiety.

Fifty-eight per cent of the women who had no chronic conditions when the study started developed multiple chronic diseases over the 20-year study.

"Crucially, we found middle-aged women with the lowest levels of relationship satisfaction were more than twice as likely to develop multiple chronic conditions as those who were very satisfied with their relationships," said Dr Xu.

It shows social relationships' quality should be considered part of preventive health, said Professor Gita Mishra of the Centre of Research Excellence in Women and Non-Communicable Diseases.

"It's normal to accumulate multiple chronic conditions as we age, but any progress we make towards disease prevention will improve our quality of life and reduce the burden on our healthcare system," Professor Mishra said.

The research was conducted as part of the Australian Longitudinal Study on Women's Health by the University of Queensland and the University of Newcastle.

The research is published in General Psychiatry.