Osteoporosis International

, Volume 14, Issue 12, pp 1007–1012

Impact of postural deformities and spinal mobility on quality of life in postmenopausal osteoporosis

Authors

    • Department of Orthopedic SurgeryAkita University School of Medicine
  • E. Itoi
    • Department of Orthopedic SurgeryAkita University School of Medicine
  • M. Kobayashi
    • Department of Orthopedic SurgeryAkita University School of Medicine
  • H. Kodama
    • South Akita Orthopedic Clinic
Original Article

DOI: 10.1007/s00198-003-1510-4

Cite this article as:
Miyakoshi, N., Itoi, E., Kobayashi, M. et al. Osteoporos Int (2003) 14: 1007. doi:10.1007/s00198-003-1510-4
  • 506 Views

Abstract

The objective of the study was to evaluate the impact of postural deformities and spinal mobility on quality of life (QOL) in patients with spinal osteoporosis. A total of 157 postmenopausal women aged over 60 years with osteoporosis were divided into five groups according to their postural deformities: round back (RB, n=41), hollow round back (HRB, n=33), whole kyphosis (WK, n=40), lower acute kyphosis (LAK, n=18), and normal posture (NP, n=25). QOL was evaluated using the Japanese Osteoporosis QOL Questionnaire (JOQOL) proposed by the Japanese Society for Bone and Mineral Research. This questionnaire contains six domains, with higher scores indicating higher levels of QOL. The number of vertebral fractures, thoracic kyphosis and lumbar lordosis angles, and spinal range of motion (ROM) during maximum flexion and extension were also measured with radiographs. Total QOL scores in RB, HRB, WK, and LAK groups were significantly lower than those in the NP group, and those in WK group were even lower compared with the other groups (P<0.05). All the groups with postural deformities, but not the NP group, showed significant positive correlations between total QOL score and spinal ROM (0.521≤r≤0.747, P<0.05). Total QOL score showed a significant correlation with age, number of vertebral fractures, lumbar lordosis angle, and spinal ROM in a total of 157 patients. However, multiple regression analysis revealed that spinal ROM best correlated with total QOL score. We concluded that QOL in patients with osteoporosis was impaired by postural deformities, especially by whole kyphosis, and that spinal mobility has a strong effect on QOL in these patients.

Keywords

OsteoporosisPostural deformityQuality of lifeSpinal mobility

Introduction

It is well known that vertebral fractures, one of the common complications of osteoporosis, cause functional impairment [1,2,3,4,5]. Previous studies also pointed out that progression of spinal osteoporosis with vertebral fractures resulted in a progressive decline on quality of life (QOL) [6,7,8,9,10,11]. Vertebral fractures also cause postural deformities that induce chronic back pain and disability in physical activities [1,5,12,13,14]. Several types of postural deformities exist according to the number, severity, and location of vertebral fractures (upper or middle thoracic, thoracolumbar, or lumbar). Satoh et al. [1] classified osteoporotic postural deformities into the following five groups based on changes of the physiological thoracic and lumbar curvature: 1) normal posture without apparent change in spinal curve; 2) round back with increased thoracic kyphosis and normal lumbar lordosis; 3) hollow round back with increased thoracic kyphosis and lumbar lordosis; 4) whole kyphosis with extensive kyphosis from thoracic to lumbar spine; and 5) lower acute kyphosis with localized lumbar kyphosis with straight thoracic spine. These postural deformities induce abnormal stress on supporting structures of the spinal column and cause chronic back pain, which usually develops while standing, walking, or doing other activities of daily living [1]. Despite the growing number of individuals who have osteoporosis, to the best of our knowledge, no studies have quantified impairments in QOL based upon postural deformities.

In the clinical setting, we sometimes find that QOL varies greatly among those with the same postural deformity. Observing these patients, we noticed that the mobility of the spine was significantly different: those with high QOL had greater mobility of the spine than those with low QOL (unpublished data). Therefore, in addition to postural deformities, impact of spinal mobility on QOL in spinal osteoporosis also has to be clarified. Previous studies have shown that spinal range of motion and movement velocities measured by a lumbar motion monitor were significantly reduced in the osteoporosis group compared with the osteopenia group [15]. It has also been reported that patients with osteoporotic postural deformities have shown markedly limited lumbar extension [1]. However, data documenting whether or not spinal mobility in patients with osteoporotic postural deformities affect QOL have been unavailable. Thus, the two purposes of this study were: 1) to determine the effect of osteoporotic postural deformities on QOL, and 2) to determine the effect of spinal mobility on QOL impairments caused by osteoporotic postural deformities.

Materials and methods

Patients

A total of 157 postmenopausal women with osteoporosis aged over 60 years were enrolled in the present study. The diagnosis of osteoporosis was made according to the criteria proposed by the Japanese Society for Bone and Mineral Research (JSBMR) [16]. Briefly, patients with bone mineral density less than 70% of young adult mean or with fragility fracture were diagnosed as having osteoporosis.

Exclusion criteria were as follows: 1) women with a history of metabolic bone disease, malignancy, or recent anti-osteoporotic treatment (with the exception of calcium and vitamin D); 2) patients with hip fractures; 3) chronic glucocorticoid usage; 4) a concomitant illness that would substantially influence the patient’s QOL (such as chronic pulmonary disease, asthma, angina, chronic congestive heart failure, stroke, blindness); 5) other diseases that might explain the patient’s back pain (such as scoliosis, lumbar spondylolisthesis, lumbar disc disease); 6) patients with documented vertebral fractures within the last 6 months. Therefore, the back pain of patients enrolled in the present study indicated chronic back pain that was not attributed to a fresh vertebral fracture.

According to the classification of the postural deformities in osteoporosis proposed by Satoh et al. [1] (Fig. 1), the patients were divided into the following five groups: normal posture (NP, n=25), round back (RB, n=41), hollow round back (HRB, n=33), whole kyphosis (WK, n=40), and lower acute kyphosis (LAK, n=18).
Fig. 1

Representative lateral radiographs with or without postural deformities in spinal osteoporosis: A normal posture (NP); B round back (RB); C hollow round back (HRB); D whole kyphosis (WK); and E lower acute kyphosis (LAK)

QOL evaluation

QOL was evaluated using the Japanese Osteoporosis QOL Questionnaire (JOQOL, QOL Evaluation Committee, Japanese Society for Bone and Mineral Research, 2000 Edition) [17]. This questionnaire was developed based on the Osteoporosis Assessment Questionnaire (OPAQ) [18] and Qualeffo-41 [6] with modification according to our lifestyle. JOQOL demonstrates a high correlation with SF-36 (r=0.78) as well as high reproducibility (test-retest, r=0.92) [17]. JOQOL contains 38 items in six domains: pain (5 items, 20 points), activities of daily living (ADL; 16 items, 64 points), recreation and social activity (5 items, 20 points), general health (3 items, 12 points), posture and figure (4 items, 16 points), and falls and psychological factors (5 items, 20 points). Scores for each item range from 0 to 4. The full score is 152, and a higher score indicates a higher level of QOL. Each domain score and total scores were compared between the groups.

Radiographic measurements

Total spine X-ray films in lateral views in neutral/flexion/extension in standing, and flexion/extension in the lateral decubitus position were taken with a film-tube distance of 1.8 m. The anterior, central, and posterior heights of each of the vertebral bodies from T4 to L5 in a neutral standing X-ray film were measured using a caliper. The precision of this measurement was 2–3% in coefficient of variation [19]. Vertebral fracture was considered present if at least one of three height measurements (anterior, middle, and posterior) of one vertebra had decreased by more than 20% compared with the height of the nearest uncompressed vertebral body [19]. Thoracic kyphosis angle (T4–T12) and lumbar lordosis angle (L1–L5) were measured in a neutral standing X-ray film. Spinal range of motions (ROM) from T4 to L5, both in standing and lateral decubitus positions, were calculated using flexion and extension X-ray films. All radiographic data were reviewed by the first author.

Data analysis

All data were presented as the mean with standard deviation (SD) and analyzed using a statistical package (StatView; SAS Institute Inc., Cary, N.C., USA). Statistical differences among groups were compared using Fisher’s protected least significant difference method (post-hoc test) for multiple comparisons in a one-way analysis of variance. Correlation between variables was analyzed using Pearson’s correlation coefficient and simple regression analysis. Further analyses using multiple regression were conducted to determine which variables best correlated with QOL (both total QOL score and all domain scores). All possible continuous variables obtained in this study were included in this multiple regression model. Postural deformities were not included in this model because they were categorical variables that could not be arranged. There were no missing data in the analyses. Probability values less than 0.05 were considered statistically significant.

Results

Demographics of each group

Patients in the round back (RB), hollow round back (HRB), whole kyphosis (WK), and lower acute kyphosis (LAK) groups were significantly older and had more fractured vertebrae than those in the normal posture (NP) group (Table 1). Thoracic kyphosis angles were significantly greater in the RB, HRB, and WK groups and smaller in the LAK group compared with those in the NP group. Lumbar lordosis angles were significantly greater in the HRB group and smaller in the WK and LAK groups than those in the NP and RB groups. Spinal ROM in both standing and lateral decubitus positions was significantly less in all postural deformity groups as compared with the NP group.
Table 1

Comparisons of radiologic variables and QOL score in osteoporotic patients with or without postural deformity. NP normal posture; RB round back; HRB hollow round back; WK whole kyphosis; LAK lower acute kyphosis; ANOVA one-way analysis of variance; NS not significant. The data are presented as mean (SD)

Variable

NP (n=25)

RB (n=41)

HRB (n=33)

WK (n=40)

LAK (n=18)

ANOVA

Age (years)

69.5 (6.6)

76.2 (5.9)a

77.1 (6.2)a

77.2 (6.1)a

74.9 (6.4)a

<0.0001

No. of vertebral fractures

1.0 (0.8)

4.3 (2.7)a

4.8 (2.1)a

5.5 (2.5)a,b

2.9 (0.8)a,b,c,d

<0.0001

Thoracic kyphosis angle (T4–T12)

28.2 (5.1)

54.1 (12.9)a

63.6 (13.2)a,b

39.5 (11.3)a,b,c

13.8 (18.4)a,b,c,d

<0.0001

Lumbar lordosis angle (L1–L5)

24.3 (6.8)

20.2 (7.8)

43.3 (5.4)a,b

−12.5 (12.5)a,b,c

−17.7 (20.8)a,b,c

<0.0001

QOL

Pain

16.7 (3.9)

12.4 (4.9)a

13.1 (4.9)a

11.8 (4.1)a

12.0 (4.1)a

0.0003

Activity of daily living

58.5 (5.5)

48.4 (11.3)a

44.8 (16.1)a

36.5 (12.5)a,b,c

43.4 (12.2)a,d

<0.0001

Recreation and social activity

8.7 (3.4)

7.9 (4.8)

7.2 (4.4)

6.4 (4.0)

7.1 (4.4)

NS

General health

5.8 (1.9)

4.8 (2.2)

5.0 (2.1)

4.0 (2.4)a

3.9 (2.0)a

0.0124

Posture and figure

11.2 (3.1)

7.3 (3.5)a

7.7 (3.6)a

6.1 (4.1)a

7.4 (4.0)a

<0.0001

Falls and physiological factors

13.0 (3.6)

10.6 (4.5)a

10.7 (4.3)a

8.9 (4.4)a

11.0 (3.9)

0.0075

Total QOL score

113.9 (12.2)

91.5 (23.6)a

88.5 (24.5)a

73.6 (22.3)a,b,c

86.8 (20.6)a,d

<0.0001

Spinal ROM

Standing position

51.9 (14.9)

29.6 (16.4)a

23.1 (12.1)a

22.4 (18.6)a,b

22.2 (10.3)a

<0.0001

Lateral decubitus position

50.5 (15.4)

29.6 (12.9)a

26.7 (13.1)a

21.7 (14.8)a,b

20.6 (7.9)a,b

<0.0001

a,b,c,dIndicate significant differences (P<0.05) between: aNP, bRB, cHRB, and dWK

Postural deformities and QOL in osteoporosis

The pain domain scores, ADL domain scores, and posture and figure domain scores in the RB, HRB, WK, and LAK groups were significantly less than those in the NP group (Table 1). Furthermore, ADL was significantly more impaired in the WK group than in the others. There were no significant differences in the domains of recreation and social activity among the groups. The general health domain scores were significantly lower in the WK and LAK groups than in the NP group. The domain scores in falls and psychological factors were significantly lower in the RB, HRB, and WK groups than in the NP group. Similar to the ADL domain scores, the total QOL scores was significantly less in all postural deformity groups as compared with the NP group. Among the former, it was significantly more impaired in the WK group than in the others.

Spinal mobility and QOL in osteoporosis

The NP group showed no significant correlations between total QOL score and spinal ROM both in standing and lateral decubitus positions (Table 2). On the other hand, all the groups with postural deformities showed significant positive correlations between total QOL score and spinal ROM in both positions.
Table 2

Correlations between total QOL score and spinal ROM in osteoporotic patients with or without postural deformity. NP normal posture; RB round back; HRB hollow round back; WK whole kyphosis; LAK lower acute kyphosis

Standing position

Lateral decubitus position

Pearson’s correlation coefficient (r)

Significance (P)

Pearson’s correlation coefficient (r)

Significance (P)

NP (n=25)

0.108

0.6186

0.172

0.4147

RB (n=41)

0.560

0.0002

0.616

<0.0001

HRB (n=33)

0.747

<0.0001

0.692

<0.0001

WK (n=40)

0.627

<0.0001

0.657

<0.0001

LAK (n=18)

0.521

0.0252

0.666

0.0019

When analyzing patients with and without postural deformity together, significant positive correlations were observed between the total QOL score and spinal ROM in both positions (Table 3). Spinal ROM in both positions also showed significant positive correlations with all the domain scores. Correlations between each domain score/total QOL score and other estimated variables were also evaluated. Age showed significant negative correlations with pain, ADL, and total QOL score. Number of vertebral fractures showed significant negative correlations with all the domain scores and total QOL score. The thoracic kyphosis angle showed a significant negative correlation with the posture and figure domain score. The lumbar lordosis angle showed significant positive correlations with pain, ADL, recreation and social activity, general health, and total QOL score.
Table 3

Correlations between QOL score (total QOL score and domain scores) and estimated variables in the study patients

Variables

Pain

Activity of daily living

Recreation and social activity

General health

Posture and figure

Falls and physiological factors

Total QOL score

Age

−0.177*

−0.342***

−0.100

0.061

−0.097

−0.007

−0.254**

No. of vertebral fractures

−0.300***

−0.362***

−0.196*

−0.179*

−0.400***

−0.179*

−0.415***

Thoracic kyphosis angle (T4–T12)

−0.130

−0.049

−0.036

0.038

−0.298***

0.119

−0.123

Lumbar lordosis angle (L1–L5)

0.169*

0.324***

0.176*

0.184*

0.151

0.141

0.310***

Spinal ROM

Standing position

0.429***

0.616***

0.386***

0.327***

0.397***

0.415***

0.658***

Lateral decubitus position

0.424***

0.655***

0.368***

0.404***

0.481***

0.404***

0.688***

Data represent Pearson’s correlation coefficient (r). *P<0.05, **P<0.01, or ***P<0.001

Multiple regression analysis revealed that the most important predictor of the total QOL score was the spinal ROM in lateral decubitus position, followed by the spinal ROM in standing position, and the lumbar lordosis angle (Table 4). All the other variables were not significant for the total QOL score. With regard to each domain score, the most important predictor of the ADL was the spinal ROM in lateral decubitus position, followed by the spinal ROM in standing position and age. The most important predictor of the posture and figure was the thoracic kyphosis angle, followed by the spinal ROM in lateral decubitus position, the lumbar lordosis angle, and age. This multiple regression model showed no significant predictor for other domain scores (pain, recreation and social activity, general health, and falls and psychological factors).
Table 4

Multiple regression analyses on QOL score (total QOL score and domain scores) in study patients

Variables

Pain

Activity of daily living

Recreation and social activity

General health

Posture and figure

Falls and physiological factors

Total QOL score

Intercept

14.000**

57.800***

6.541

−1.569

2.528

3.054

82.354***

Age

−0.035

−0.373*

−0.023

0.067

0.093*

0.080

−0.193

No. of vertebral fractures

−0.098

−0.190

−0.060

−0.110

−0.190

−0.075

−0.722

Thoracic kyphosis angle (T4–T12)

−0.029

0.032

0.001

0.007

−0.084***

0.056

−0.103

Lumbar lordosis angle (L1–L5)

0.026

0.077

0.014

0.004

0.044**

0.044

0.185*

Spinal ROM

Standing position

0.053

0.220*

0.058

0.022

0.018

-0.030

0.392***

Lateral decubitus position

0.047

0.272**

0.030

0.023

0.093**

0.021

0.510***

Data represent regression coefficient (r) in multiple regression analysis. *P<0.05, **P<0.01, or ***P<0.001

Discussion

The functional impairment caused by vertebral fractures in patients with osteoporosis can be substantial [1,2,3,4,5]. Multiple vertebral fractures result in postural deformities that could cause significant functional impairment in activities of daily living [1,5,12,13,14]. Huang et al. [3] found that in postmenopausal women, the number of vertebral fractures was a significant predictor of poor performance in functional reach and gait speed. Ryan et al. [13] demonstrated in 231 elderly individuals that kyphosis was associated with reduced gait and stair-climbing function. These functional impairments also cause the QOL to decline in patients with spinal osteoporosis [6,7,8,9,10,11]. The present study describes the effect of different types of postural deformities on QOL in spinal osteoporosis. The results showed that QOL in patients with osteoporosis was impaired by all types of postural deformities, especially by whole kyphosis.

Postural deformities begin with localized kyphosis due to either fracture or asymptomatic insidious collapse at the thoracic and/or thoracolumbar spine [1]. This increased kyphosis (round back) can be readily compensated by increasing lumbar lordosis, resulting in the formation of the hollow round back [1]. Compensated upper thoracic lordosis for wedged vertebral fractures at the thoracolumbar junction results in lower acute kyphosis. If progressing round back cannot be compensated by lumbar lordosis, kyphosis extends down to the lumbar region, resulting in whole kyphosis. Therefore, whole kyphosis cannot be compensated by other spinal segments. Because lumbar kyphosis is thought to be related to weakness of the spinal extensors [20], whole kyphosis usually forces the patient to use a cane while standing and walking [1]. These uncompensated conditions seemed to contribute impairment of all the domain scores in the whole kyphosis group, especially in the ADL domain score, resulting in a significant reduction in the total QOL score compared with other postural deformities.

The present results also demonstrated reduced spinal ROM (spinal mobility) in patients with postural deformities compared with normal posture control. In addition, the present results further demonstrate a statistically significant correlation between spinal ROM and QOL in all the subjects. Decreased mobility of the spine may lead to an increased kyphosis and weakness of the paravertebral muscles, as well as the development of impaired physical function [4]. Back pain also influences functional mobility in osteoporosis [21]. Lyles et al. [2] found that women with vertebral fractures had reduced maximal trunk torque, spine motion, functional reach, mobility skills, and gait speed. Several studies have reported that vertebral fractures [5,22] and kyphosis [12] are the underlying cause of back pain in osteoporosis and these factors influence balance [23] and functional mobility [2,3,13]. We postulated that spinal mobility and its relationship to QOL might be different between standing and lateral decubitus positions because standing position could be more influenced by impaired balance of patients with postural deformity. However, there were no significant differences between the positions in variables measured in the present study.

Total QOL score in this study also had significant correlations with age, number of vertebral fractures, and lumbar lordosis. However, multiple regression analysis revealed that the spinal ROM was best correlated with total QOL score. Although patients with postural deformity showed moderate to high correlations between QOL and spinal ROM, patients with normal posture did not show significant correlations between them. Because women reporting fractures with no postural manifestations had similar physical activities and adaptations to those in normal non-osteoporotic control [14], their QOL is higher than those in patients with postural deformities. Therefore, spinal mobility seemed to have less impact on QOL in patients with normal posture. We conclude that spinal mobility is an important factor, which has a strong effect on QOL when osteoporotic patients have postural deformities.

There are several limitations in this study. First, the classification of the postural deformities used in this study was defined based on changes in the physiological thoracic and lumbar curvatures observed by eye [1]. This classification clearly defines typical deformity in each group, but there might have been some overlaps between the groups [24]. Classification using angle measurement on radiographs may be more precise, but less convenient and useful in the clinical setting. Second, the number of the subjects in our study was much smaller than the previous studies evaluating QOL [6,7,8,9,10,11]. However, we would like to emphasize that this is the first study demonstrating relationships between the spinal ROM and QOL in osteoporotic patients. Third, because the present study used the JSBMR criteria for the diagnosis of osteoporosis [16], there might be a significant discrepancy when comparing the study patients to other patients with osteoporosis based on the common criteria by the World Health Organization, which defines osteoporosis when BMD levels fell more than 2.5 SD below the young adult mean [25]. Finally, other possible confounding factors such as body mass index, effects of other fracture types (i.e. wrist and ribs), smoking status, and exercise level could not be evaluated in the present study because these data were not recorded. These factors should also be controlled in the future study to confirm whether postural deformities and spinal mobility actually affect on OQL in spinal osteoporosis.

In summary, the present study evaluated the impact of postural deformities and spinal mobility on QOL in patients with spinal osteoporosis. QOL in these patients was impaired by postural deformities, especially by whole kyphosis. Spinal mobility has strong impact on QOL in patients with postural deformities.

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2003