Osteoarthritis is the most common form of arthritis, affecting around 8.8 million people in the UK. The causes of osteoarthritis are complicated, with a person’s risk of developing osteoarthritis depending on both genetic and environmental factors.
We still have much to learn about how these two components work together to cause disease. However, research into lifestyle factors contributing to osteoarthritis – supported by funding from us – identified a number of occupations associated with a high risk of osteoarthritis.
- coal mining
- carpet fitting
- carpet and floor laying.
Linking heavy lifting with osteoarthritis of the hip
Professor Peter Croft at the University of Keele, in collaboration with Professor David Coggon and Professor Cyrus Cooper at the University of Southampton, conducted a study in which they compared 611 people with hip osteoarthritis awaiting hip replacement surgery with 611 healthy individuals.
Detailed lifestyle information was collected from both groups including:
- occupational and leisure activities
- body build
- smoking status
- alcohol consumption.
In men, an association was found between occupational heavy lifting, defined as regularly lifting 10 kg or more for prolonged periods, and hip osteoarthritis.
The risk of hip osteoarthritis was even higher in men lifting 25 kg or more, with farmers most frequently reporting lifting the heaviest loads among the hip osteoarthritis group. The researchers suggested that the high rate of hip osteoarthritis seen in farmers was due to the amount of heavy lifting done as part of their job.
Kneeling and squatting linked to osteoarthritis of the knee
In a separate study, people with painful knee osteoarthritis were recruited from a large general practice and compared to another group without knee osteoarthritis.
The results suggested the risk of knee osteoarthritis was increased by prolonged occupational kneeling or squatting.
A larger investigation was later carried out which compared 518 people with knee osteoarthritis awaiting surgery with 518 healthy individuals. The risk of knee osteoarthritis was highest among people whose occupations involved prolonged kneeling or squatting, in particular when the occupation also involved heavy lifting.
Osteoarthritis as an occupational disease
The evidence from these studies contributed to reports produced by the Industrial Injuries Advisory Council (IIAC) reports on knee osteoarthritis and hip osteoarthritis. The IIAC is an independent scientific advisory body who review scientific and medical evidence and advise the Department for Work and Pensions on proposed changes to the Industrial Injuries Scheme.
The IIAC’s reports resulted in legislation being changed to include knee osteoarthritis in coal miners, carpet fitters and carpet/floor layers – and hip osteoarthritis in farmers – in the list of prescribed industrial injuries.
This meant that people who had developed knee or hip osteoarthritis as a result of working in one of these occupations were able to claim Industrial Injuries Disablement Benefit.
Depending on their level of disability, people eligible for the benefit receive between £33 and £168 per week. By 2011, over 16,000 former coal miners had successfully made a claim since the change to the legislation in 2009.
This research also contributed to the recognition of knee osteoarthritis as an occupational disease in other countries, including Germany and Denmark.