Prevalence of osteoarthritis, osteoporotic vertebral fractures, and spondylolisthesis among the elderly in a Japanese village

Journal of Orthopaedic Surgery, Apr 2006 by Horikawa, K, Kasai, Y, Yamakawa, T, Sudo, A, Uchida, A

ABSTRACT

Purpose. To study the prevalence of osteoarthritis, osteoporotic vertebral fractures, and spondylolisthesis among elderly residents of a Japanese village and to examine the correlation between radiographic evidence of abnormality and lower back pain.

Methods. 205 men (mean age, 70.7 years) and 323 women (mean age, 70.5 years) in a Japanese village participated in this cross-sectional study. Plain lateral radiographs were taken from the lower thoracic spine to the sacral spine. They were evaluated by 3 independent orthopaedic surgeons for degree of osteoarthritis (using Weiner grading system) and the presence of osteoporotic vertebral fractures and spondylolisthesis.

Results. The prevalence of osteoarthritis in elderly Japanese villagers was 38.3%, whereas that of osteoporotic vertebral fractures and spondylolisthesis was 17.8% and 8.9%, respectively. There was no significant difference in osteoarthritis between men and women, but osteoporotic vertebral fractures and spondylolisthesis were significantly more common in females (p

Conclusion. The prevalence of spondylolisthesis in elderly Japanese was much lower than that in whites or African Americans. The prevalence of osteoarthritis or osteoporotic vertebral fractures was comparable with other English or US studies. Radiographic evidence of osteoarthritis, osteoporotic vertebral fractures, and spondylolisthesis is not necessarily associated with lower back pain.

Key words: epidemiology; osteoarthritis; osteoporosis; spinal diseases; spinal fractures; spondylolisthesis

INTRODUCTION

The precise prevalence of degenerative spinal disease among the elderly is difficult to determine because many patients remain asymptomatic and do not develop overt symptoms (e.g. lower back pain) or request medical treatment despite the radiographic evidence of abnormalities.

We performed a cross-sectional study using plain radiographs to investigate the prevalence of abnormalities of the thoracic and lumbar spine (e.g. osteoarthritis, osteoporotic vertebral fractures, and spondylolisthesis) among elderly residents of a Japanese village, and to examine the correlation between abnormalities on plain radiographs and the presence or absence of lower back pain.

MATERIALS AND METHODS

Between June and July 2001, 528 people (205 males and 323 females) aged 65 years or more residing in a fishing/farming village located in Nansei-cho, Mie prefecture, Japan were studied. No participants reported any remarkable history of trauma to the thoracolumbar spine. Our sample accounted for 22.9% of 2306 residents of Nansei-cho aged 65 years or more, according to the 1999 census. The mean age of the participants was 70.6 years (range, 65-92 years). There was no significant difference in the mean age between males and females (70.7 versus 70.5 years). Participants were questioned about the presence or absence of lower back pain in the previous 6 months.

Plain lateral radiographs were taken from the lower thoracic spine to the sacral spine and were evaluated by 3 independent orthopaedic surgeons for the degree of osteoarthritis and the presence or absence of osteoporotic vertebral fractures and spondylolisthesis.

The degree of osteoarthritis of the lumbosacral spine was evaluated using a radiographic scoring system described by Weiner et al.1 Osteoarthritis was graded from 0 to 3: grade 0 indicates no disease, defined by normal disc height, no spur formation, no eburnation, and no gas; grade 1 indicates mild disease, defined by 75% disc space narrowing, large spur formation, marked eburnation, and presence of gas. The grading was confirmed if at least 2 surgeons were in agreement. The diagnosis of osteoarthritis was made if the grade was 2 or higher. The consistency of the grading of the 3 observers was 92.4%, indicating high inter-observer reliability.

The diagnosis of osteoporotic vertebral fractures was made if anterior wedge fractures or crush fractures in the vertebrae were identified by at least 2 observers. The consistency of the diagnosis of the 3 observers was 97.6%, once again indicating high inter-observer reliability.

Diagnosis of spondylolisthesis was made if there was anterior or posterior slippage of ≥3 mm in the vertebrae.

Statistical analysis was performed using Chi squared test and Student's t test, with the significance level set at p

RESULTS

Over half (n=267, 50.6%) of the 528 participants reported lower back pain: 93 (45.4%) of 205 males and 174 (53.9%) of 323 females. More females than males tended to have lower back pain, but the difference was not significant. No significant difference was noted between lower back pain and age: 121 (48.8%) of 248 aged 65 to 69 years, 100 (53.8%) of 186 aged 70 to 74 years, 36 (49.3%) of 73 aged 75 to 79 years, and 10 (47.6%) of 21 aged 80 years or more had lower back pain.

251 (47.5%) of 528 participants had grade-1 osteoarthritis, and 202 (38.3%) had either grade 2 or 3. More males tended to develop osteoarthritis than females (42.4% versus 35.6%), but the difference was not significant (Table 1). There was no significant correlation between age and grade of osteoarthritis (Table 2). In participants with osteoarthritis (grade 2 or 3), 112 (55.4%) of 202 had lower back pain, while 155 (47.5%) of 326 without osteoarthritis (grade 0 or 1) developed lower back pain. Lower back pain therefore did not correlate with osteoarthritis. Nonetheless, the incidence of lower back pain increased as the grade of osteoarthritis increased, and there was a significant difference in the incidence of lower back pain between participants with grade 0 and 3 osteoarthritis (p