Obesity doubles the risk of disc degeneration in adulthood and could lead to a serious need for back surgery, a University of Hong Kong study has revealed.
The research found that more than two-thirds of adults aged at least 21 had disc degeneration, which can cause severe chronic pain. Some 36 per cent of them were overweight, 9 per cent were obese and about half were of normal weight.
Researchers at HKU's Li Ka Shing Faculty of Medicine studied the magnetic resonance imaging scans of a cross-section of about 2,600 people.
'Those who are overweight will have an increased likelihood of severe pain and the need for lower back surgery in late life,' said Professor Kenneth Cheung Man-chee, of the university's orthopaedics and traumatology department, who carried out the study with Dr Dino Samartzis.
Disc degeneration disease was irreversible and could cause long-term suffering, Cheung said. This could include serious lower back pain, which might prevent patients from leading a normal work and social life.
The findings are based on data from the Hong Kong Degenerative Disc Disease Cohort, the largest study of its kind in the world.
Launched in 2001, it addresses disc degeneration and lower back pain by tracking the health of more than 3,500 southern Chinese volunteers aged 10 to 80.
The HKU study also found that the more overweight an adult was, the more serious the backache would be, compared with adults who were in the normal weight range. People who were obese had a 79 per cent increased risk of disc degeneration, while those who were overweight had a 30 per cent risk.
It has long been known that ageing, genetics and biomechanics - the structure and function of biological systems - are contributory causes of disc degeneration.
The findings were published in the latest issue of the medial journal Arthritis and Rheumatism. They are in line with a previous study by the same team that found a third of teenagers suffered from backache, and the condition was three times more likely if they were overweight.
The number of people overweight or obese in Hong Kong is rising. Department of Health data shows that in 2010, 39 per cent of adults aged 18 to 64 were overweight or obese.
Degeneration of the intervertebral discs - the joints of the spine - was on the increase in Hong Kong and the mainland, said Dr Robin Mellecker, a fellow at HKU's Institute of Human Performance.
'This is because populations are eating and sitting more,' she said.
The body mass index (BMI) figure at which a person is classed as obese. Height and weight are used to estimate how much body fat you have