Systemic Sclerosis in Greece

Systemic sclerosis (SSc) is a relatively rare connective tissue disease. Its etiology remains uncertain, although several environmental and genetic factors have been suggested as potential risk factors for SSc. Descriptive epidemiological studies performed in different countries indicate important regional variations of disease occurrence. Studies from Northern Europe and Japan gave several fold lower incidence and prevalence rates than those from Australia and the USA. These variations, although possibly related to methodological differences in case definition and ascertainment, indicate a differential susceptibility to SSc on the basis of differential exposure to environmental triggers and different genetic background.

Epidemiological studies performed in several countries suggest significant geographic variations in the occurrence of SSc.

Introduction

SSc patients in northwest Greece have similar survival rates compared with patient series from other countries. The SMR indicates a twofold higher mortality in comparison to the general population of the study area. This increased mortality was observed among women, but not among men. Other studies have shown that SSc patients have a higher mortality compared with the general population in both sexes.

The increased mortality of SSc patients has been attributed to an increase in SSc-related and unrelated causes of death. It is possible that the unrelated mortality is indirectly associated with SSc, as the disease could be considered a risk factor for increased morbidity and mortality for other illnesses. In the present study, the causes of death directly related to SSc were mainly cardiopulmonary and renal diseases, while the causes of death not directly related to SSc were cancer and vascular diseases. Other studies indicate also an increased frequency of malignancies and macrovascular disease among SSc patients.

Causes

Several environmental and occupational factors may be linked with SSc, but their role still remains uncertain. On the other hand, dietary factors such as olive oil and fish consumption or even the Mediterranean diet may be protective against disease development. This may also explain the different disease expression in our patients, especially the low frequency of renal involvement. In addition, sun exposure and ultraviolet radiation may have immunosuppressive properties. Finally, the milder climate conditions in the Mediterranean area also may contribute to different environmental factors from those of United States and northern European countries. However, the role of the above factors still remains uncertain.

References

• Matucci-Cerinic M, D’Angelo S, Denton CP, Vlachoyiannopoulos P, Silver R. Assessment of lung involvement. Clin Exp Rheumatol 2003; 21(Suppl. 29):S19-23.

• Steen VD, Mayes MD, Merkel PA. Assessment of kidney involvement. Clin Exp Rheumatol 2003;21(Suppl. 29):S29-31.

• Preliminary criteria for the classification of systemic sclerosis (scleroderma). Subcommittee for scleroderma criteria of the American Rheumatism Association Diagnostic and Therapeutic Criteria Committee. Arthritis Rheum, 1980;23:581-588.