Knee osteoarthritis is an occupational hazard for many jobs and unpaid roles beyond the usual suspects of physically demanding work such as the construction industry, a new study shows.

Stay-at-home parents, cleaners and office workers who engage in repeated standing, kneeling and squatting may be just as likely as tradies to develop osteoarthritis and need knee reconstruction, according to a new meta-analysis led by researchers from the Rheumatology Department, Royal North Shore Hospital, and Sydney University.

The study, which covered 71 studies and almost one million people, found as expected an increased risk of knee OA in construction  workers, agriculture workers and miners.

But it also found increased risks of up to 93% for houseworkers, service workers  and cleaners who perform high levels of lifting, kneeling, climbing, squatting and standing, compared to people in sedentary activity roles.

There was no increased risk of OA seen in some manual occupations such as forestry or fishery workers, machine operators, plumbers, electricians, technicians and, posties.

The researchers said it was not surprising to see an increased risk of OA in construction workers such as bricklayers and floor layers, who would have high knee loads from frequent severe knee flexion when kneeling  and squatting during their working day.

But they said little attention had been paid to other occupations and unpaid roles such as homemakers and carers who “often  engage  in  prolonged  standing  activities  and  frequently  perform  household  tasks such as mopping/cleaning which involve frequent bending, kneeling and squatting.”

“Cleaners  frequently engage in awkward knee postures and repetitive tasks and movements that mirror  many household  tasks. These  working areas require  special attention,  especially for  unpaid full-time housewives or carers,” they said.

“With people working and living longer knee osteoarthritis is an area of concern even in service-focused developed nations, including in mid-risk occupations such as cleaning and full-time, unpaid housework and caring,” said study lead author Dr Xia Wang, of the Institute of Bone and Joint Research in the Kolling Institute, Sydney University.

She said the findings could be used to inform workplace regulators and insurers and help identify people who could be targeted  with tailored prevention strategies for knee OA such as ergonomic interventions.

Professor David Hunter, a study co-author on the paper, said the findings were important since it was projected that osteoarthritis would affect one in eight people within 15 years, in large part attributable to lifestyle issues such as growing rates of obesity and reduced exercise.

“Knee osteoarthritis is a leading cause of loss of work and disability worldwide and can necessitate invasive surgery including total knee replacement, so preventing occupational hazards is critical,” he said.

The findings are published in Arthritis Care and Research.