Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.

Smoking Is Associated with Syndesmophyte Development in Ankylosing Spondylitis.

Solmaz1,  Dilek, Akar2,  Servet, Sari3,  Ismail, Soysal1,  Ozgul, Gerdan1,  Vedat, Onen2,  Fatos, Akkoc2,  Nurullah

MD, Izmir, Turkey
Professor, Izmir, Turkey
Dokuz Eylul University School of Medicine, Izmir, Turkey


Information on risk factors for the severity of spinal involvement in ankylosing spondylitis (AS) is limited. In this cross-sectional study we examined the association of the presence of syndesmophytes with smoking, which has been suggested to be related to a more severe disease course by some authors, and with the presence of calcaneal enthesophytes, which may be an indicator of a tendency to bone formation in AS.


We included 114 patients with AS (77 male [67.5%] with a mean age of 40.7 ± 11.4 years) who had available lateral heel radiographs and vertebral X-rays for review. All patients fulfilled the modified New York criteria. Two independent readers evaluated the vertebral and lateral heel radiographs for the presence of syndesmophytes and enthesophytes at the insertion of the achilles tendon or plantar fascia. In cases of disagreement consensus was reached by second reading session. All clinical and demographic data, including disease activity (BASDAI), functional (BASFI) and mobility (BASMI) scores at the time of radiographic examination and the highest available ESR and CRP levels as well as the smoking status were obtained from the medical records. The relation of the variables with syndesmophyte formation was evaluated with phi coefficient or Spearman's rho. Logistic regression model was used to identify the independent risk factors for the presence of vertebral syndesmopytes.


Clinical and demographic features of the patients are summarized in table 1. A total of 61 (53.5%) patients had syndesmophytes and 73 (64%) had calcaneal enthesophytes. There were moderate and substantial agreement between the two readers in regard with the presence of vertebral syndesmophytes (k=0.706) and calcaneal enthesophytes (k=0.846). Univariate analysis revealed the presence of syndesmophytes was associated with smoking status, the presence of calcaneal enthesophytes as well as age, sex, highest available ESR, BASFI and BASMI (table 2). After multivariate logistic analysis smoking status, male sex, BASMI score and age remained significantly associated with the presence of syndesmophytes (table 2).

Table 1. Characteristics of the study group

 AS patients (n=114)
Age, mean ± SD40.7 ± 11.4
Male sex: n (%)77 (67.5)
Disease duration, mean ± SD (years)6.7 ± 7.9
Symptom duration, mean ± SD (years)15.1 ± 10.1
Ever-smoker: n (%)81 (71.7)
Education Level, mean ± SD (years)9.2 ± 4.0
ESR, mean ± SD43.2 ± 28.6
CRP, mean ± SD33.6 ± 42.1
BASDAI, mean ± SD3.1 ± 2.6
BASFI, mean ± SD3.5 ± 2.2
BASMI, mean ± SD3.8 ± 1.9
ASDAS ESR, mean ± SD2.7 ± 1.1
ASDAS CRP, mean ± SD2.7 ± 1.1

Table 2. Factors associated with and independently predict the presence of syndesmophyte formation.

VariablesThe presence of vertebral syndesmophyte
Rho or phipOR (95% CI)P 
Age0.394<0.0011.09 (1.02–1.7)0.008
Sex0.2180.0204.95 (1.3–18.7)0.018
Ever-Smoker0.2360.0126.26 (1.46–26.73)0.013
ESR0.2770.0031.01 (0.99–1.03)0.102
BASFI0.3140.0011.07 (0.85–1.34)0.534
BASMI0.467<0.0011.63 (1.16–2.30)0.005
Calcaneal entesophytes0.2540.0071.53 (0.47–4.97)0.472


Smoking, male sex, age and BASMI scores are independently associated with structural damage in AS. The association between the presence of calcaneal enthesophytes and syndesmophytes, which was present in univariate analysis but which disappeared after multivariate logistic regression analysis, needs to be further explored in future prospective studies.

To cite this abstract, please use the following information:
Solmaz, Dilek, Akar, Servet, Sari, Ismail, Soysal, Ozgul, Gerdan, Vedat, Onen, Fatos, et al; Smoking Is Associated with Syndesmophyte Development in Ankylosing Spondylitis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :550

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