Objectives To assess the prevalence of LTD caused by RD or any other MDG was one of the aims of a population-based epidemiological study of RD in Greece (ESORDIG study).

Methods All adult (>18 years) residents of two urban (U), one suburban (SU) and four rural (R) communities of Greece were included in this 3 year (1996–1999) study (8,547 subjects), along with 2,100 randomly selected subjects of 1 SU (1:3) and 1 R (1:2) communities. Sixteen rheumatologists performed the study and 8,740 adults were included (out of a total of 10,647, response rate 82.1%). The study included a detailed interview based on a standardised questionnaire. LTD was defined as ?the limitation of occupational or any other activities because of a long-term physical or mental disorder or health problem, compared to other people of the same age in good health?.

Established classification criteria (ECC) were used for the diagnosis of RD, while, for the purpose of the study, such criteria were set for RD without ECC.

Results From 2,393 subjects (out of 8,740, 27.4%) suffering from RD, 394 (16.5%) also had LTD. Thus, the prevalence of LTD caused by RD was 4.5% in the general population (GP), being higher in women (6.2%) than in men (2.8%, p < 0.0005). LTD prevalence increased with age, being 11.6% in subjects >68 years, while no significant differences were observed between the three (U, SU, R) communities. The total prevalence of LTD from any cause was 9.8% in the GP and RD were the most common cause, being responsible of 46.2% of all LTD, followed by cardiovascular diseases (CVD, 22.7%). Analysis for sex, age and community revealed that RD were always the leading cause of LTD, but in men aged >58 years, CVD were first (41.3%), with RD second (25.4%).

Conclusion The results of this study show that RD, compared with other MDG, are the leading cause of LTD in the general population. Since LTD is the major contributing factor for the total indirect cost of all MDG, these findings concerning RD appear to be of considerable value in planning rheumatology research and health care services.