| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Rheumatology 1999; 38: 793-794
© 1999 British Society for Rheumatology
Letters to the Editor |
Prevalence of hip osteoarthritis and acetabular dysplasia in Kamitonda: from a longitudinal population-based epidemiological study of rheumatic diseases in Japan
Department of Orthopaedic Surgery, Shiga University of Medical Science, Otsu, Shiga,
1 Yukioka Hospital, Kita-ku, Osaka and
2 Tezukayama Hospital, Abeno-ku, Osaka, Japan
Correspondence to:
K. Inoue, Department of Orthopaedic Surgery, Setatsukinowa-cho, Otsu, Shiga, 520-2192, Japan.
SIR, We read with interest and some criticism the article by Yoshimura et al. [1] reporting a high prevalence of acetabular dysplasia and a low prevalence of hip osteoarthritis (OA) among Japanese. They compared the pelvic radiographs (P) of 99 Japanese men and 99 Japanese women aged 60–79 yr with radiographs taken at an i.v. urography (U) of British men and women aged 60–75 yr. The centre–edge (CE) angle, the acetabular depth and the minimal joint space (MJS) were compared between the two ethnic groups.
First, we would like to point out an incorrect statement that morphometric studies of acetabular anatomy have not been performed previously in the Japanese population. In the earlier period of a longitudinal population-based study of rheumatic diseases in Kamitonda, Wakayama, Japan, which began in 1965 and is still continuing, radiographic studies of OA of the hip, hand and cervical spine were performed for inhabitants aged 30 yr and above [2]. Regarding the hip joint, 737 inhabitants (398 men and 339 women) participated in the radiographic study. OA was assessed by the Kellgren and Lawrence scale, and acetabular dysplasia by measuring the CE angle. Some of the representative radiographs were brought by a senior author (KS) and kindly assessed for hip OA by Dr J. S. Lawrence, the author of the epidemiological study of OA in Leigh, UK [3], who recognized a good comparability between the studies in Leigh and Kamitonda. Regarding acetabular dysplasia, we were not aware of comparable studies on Caucasians at that time. We therefore compared our data with those of Hong Kong Chinese reported by Hoaglund et al. [4]. The Kamitonda study showed a far lower prevalence of hip OA and first carpometacarpal joint OA in Japanese than in Britons, and a higher prevalence of acetabular dysplasia than in Hong Kong Chinese. Although the results were reported in the Japanese literature, they were referenced not only by Japanese, but also by foreign researchers. The fact that the prevalence of acetabular dysplasia seen in the study by Yoshimura et al. is similar to that of older people in the Kamitonda study, which was performed about a quarter of a century ago, suggests that the acetabular morphology of one ethnic group does not change in such a period.
When we read the recent British study by Croft et al. [5], we tested the comparability of radiomorphometric variables measured in the British studies, in which U were examined, to those obtained from P adopted in the Kamitonda study. Thirty hips of 15 hospital attenders, who underwent radiography of both U and P at the first author's hospital during an interval of <3 yr and showed no pathological findings in either hip, were examined by a single observer (KI). The U and the P were separately assessed at an interval of 1 month. The acetabular depth and the MJS were significantly greater in U than in P (P=0.0002 and P=0.005, respectively) by a Wilcoxon matched pairs signed ranks test. For the CE angle, there was no significant difference (P=0.61). It is, therefore, unjustified to compare directly the MJS and the acetabular depth between the previous British studies and the Japanese study by Yoshimura et al. However, we believe that the result showing that the prevalence of acetabular dysplasia defined by the CE angle in older Japanese is higher than in older Britons is justified.
References
-
Yoshimura N, Campbell L, Hashimoto T et al. Acetabular dysplasia and hip osteoarthritis in Britain and Japan. Br J Rheumatol 1998;37:1193–7.
[Abstract/Free Full Text] - Ota H. Prevalence of osteoarthritis of the hip and other joints in Japanese population. J Jpn Orthop Assoc 1979;53:165–80.
- Kellgren LH, Lawrence JS. Osteoarthrosis and disc degeneration in an urban population. Ann Rheum Dis 1958;17:388–96.
-
Hoaglund FT, Yan ACM, Wong WL. Osteoarthritis of the hip and other joints in Southern Chinese in Hong Kong. J Bone Joint Surg 1973;55A:545–57.
[Abstract/Free Full Text] -
Croft P, Cooper C, Wickham C, Coggon D. Osteoarthritis of the hip and acetabular dysplasia. Ann Rheum Dis 1991;50:308–10.
[Abstract/Free Full Text]
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||