Table 1 Variables included in the study

Gender

1 = Boy; 2 = Girl

Age

Min = 11 years old; Max = 16 years old

Having or not having a long term disease or health problem that has been diagnosed by a doctor (Having/not having a chronic condition – CC);

1 = No; 2 = Yes

Feeling that the disease affects or not participation and regular attendance in school;

1 = No; 2 = Yes

Satisfaction with family life (Cantril, 1965)

0 = Very bad relationship; 1;2;3;4;5;6;7;8;9;10 = Very good relationship

Family Affluence Scale –FAS (Boyce et al., 2006): composed by 4 items, and used to assess familiar socioeconomic status (SES):

 “Does your family have a car, van or other mean of transport?”

1 = No; 2 = Yes, one; 3 = Yes, two or more

 “How many computers do you have at home?”

1 = None; 2 = One; 3 = Two; 4 = More than two

 Spending holidays with family in the last 12 months

1 = None; 2 = One; 3 = Two; 4 = More than two

 “Do you have a bedroom only for yourself?”

1 = No; 2 = Yes

“Feeling pressure with homework”

1 = None; 2 = A few; 3 = Some; 4 = A lot

“Perception of school competence”

1 = Very good; 2 = Good; 3 = Average; 4 = Below average