Demographic and disease characteristics of the study sample.

Percentages (N) or means (± SD) are reported. aeducational level: (1) less than six years of primary education; (2) finished six years of primary education; (3) six years primary education and less than two years of low level secondary education; (4) four years of low level secondary education; (5) four years of average level secondary education; (6) five years of high level secondary education; (7) university degree. No significant group differences were found at p≤0.05.