Jeju Haenyeo with Knee Osteoarthritis Have a 14% Lower Risk of Joint Replacement Surgery

【Financial News | Jeju = Jeong Yong-bok, reporter】 Among female patients aged 50 and older treated for knee osteoarthritis, Jeju haenyeo had a 14% lower risk of joint replacement surgery than women who were not haenyeo. Their risk of readmission within 30 days of surgery was also 30% lower, drawing attention to the link between long-term underwater activity and joint health.
According to Jeju National University Hospital on the 10th, a joint research team from the hospital’s Haenyeo Health Research Center and SMC’s Center for Clinical Epidemiology analyzed clinical data from 16,763 women aged 50 and older who received care for knee osteoarthritis at Jeju National University Hospital between 2004 and 2023.
Of the study participants, 2,390 were haenyeo and 14,373 were women who were not haenyeo. Based on medical records, the team tracked whether participants underwent joint replacement surgery and their subsequent outcomes through August 2024. The findings were published in Occupational Medicine, the official journal of the British occupational medicine society, published by Oxford University Press. The journal is indexed in SCIE, had a 2025 impact factor (IF) of 2.4, and ranked 193rd among 443 journals in the public, environmental and occupational health category.
Haenyeo were relatively older when they first sought care for knee osteoarthritis. Their average age at the first visit was 69.4, compared with 66.6 in the comparison group, a difference of 2.8 years. However, the older age at first visit alone does not establish that the onset of arthritis itself was delayed by the same amount.
A difference was also found in the risk of joint replacement surgery, an indicator of disease progression. An analysis accounting for patients’ age, arthritis severity and comorbidities found that haenyeo had a 14% lower risk of total knee replacement than the comparison group. Total knee replacement is a procedure in which the damaged surfaces of the knee joint are replaced with an artificial joint.
The analysis found that among patients with grade 4 arthritis, the most severe grade on radiographic imaging, haenyeo had a 22% lower risk of surgery than the comparison group.

Postoperative outcomes also differed. Of the 3,989 people who underwent joint replacement surgery, 652 were haenyeo and 3,337 were in the comparison group. Haenyeo had a 30% lower risk of readmission within 30 days of surgery. However, there were no statistically significant differences in postoperative complications or length of hospital stay.
The research team focused on haenyeo’s long experience of underwater work. Haenyeo dive without oxygen-supply equipment and repeatedly harvest and transport seafood. Water’s buoyancy reduces the load on the knees, while moving underwater may help strengthen muscles and improve cardiopulmonary function.
However, this was an observational study based on an analysis of past medical records. It did not establish a causal link showing that underwater activity directly slowed the progression of arthritis. The timing of hospital visits, lifestyle and genetic characteristics may also have affected the results. The participants were also patients treated at Jeju National University Hospital, so the study did not directly compare the risk of developing arthritis among all haenyeo and women in the general population.
Professor Joo Jin-deok of the Department of Neurosurgery at Jeju National University Hospital, a co-corresponding author, emphasized the importance of clinical data for analyzing the relationship between haenyeo’s long-term occupational activity and their health.
Cho Ju-hee, director of SMC’s Center for Clinical Epidemiology, said, "This study is significant as a large-scale epidemiological study based on 20 years of accumulated clinical data." She added, "Further research is needed to determine how underwater exercise can be used to prevent and manage knee osteoarthritis, which is common among older women."
This study is significant in that it analyzed the occupational characteristics of Jeju haenyeo in relation to joint health among older women. Further research that takes into account the intensity and frequency of underwater exercise and participants’ physical activity histories could expand the evidence available for developing programs to prevent arthritis and support rehabilitation in old age.


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