Table 3.

Dependent variables and instruments used for their assessment in the present study.

Global Health Score (GHS)	Life satisfaction	It was measured by the Cantril's Ladder (Cantril, 1965), with the question: “Here is a picture of a ladder. The top of the ladder ‘10’ is the best possible life for you and the bottom ‘0’ is the worst possible life for you. In general, where on the ladder do you feel you stand at the moment? Tick the box next to the number that best describes where you stand.” This variable represents the global perception adolescents have of their lives, from 0 to 10. Level of measurement: quantitative variable.
	Self-reported health	A single item asked the adolescent to consider their health at that moment, with their response fitting to one of the following four options: excellent, good, passable, or poor (Idler and Benyamini, 1997). This measure has been validated for quantitative use (Silventoinen et al., 2007). Level of measurement: ordinal variable.
	Health-related quality of life	It was measured with the Kidscreen instrument designed for a population between the ages of 8 to 18. Specifically the Kidscreen-10 version was used, which provides a global, health-related quality of life index with 10 items covering physical, psychological and social aspects (Ravens-Sieberer et al., 2001). These items, which show a Cronbach's alpha of 0.83, refer to feeling well and fit, full of energy, sad, lonely, having enough time for themselves, doing things they want in their free time, receiving fair treatment from their parents, having a good time with friends, getting on well at school and being able to pay attention/concentrate. Items were answered on a 5-point Likert scale, from 1, never, to 5, always. Level of measurement: continuous variable.
	Psycho-somatic complaint	It was measured with the HBSC-symptom checklist. It measures two aspects (Ravens-Sieberer et al., 2008): psychological complaint (nervousness, feeling low, irritability and sleeping problems) and somatic manifestations (headache, stomach-ache, back ache, and feeling dizzy), with a Cronbach's alpha of 0.83. These 8 items were answered on a 5-point Likert scale: about every day, more than once a week, about every week, about every month, and rarely or never. Level of measurement: continuous variable.
Factorial Score on the Quality of Parent-Child Relationship (QPCR)	Perceived affection	This variable was assessed by means of the 4-item subscale of the Parental Bonding Inventory-Brief Current form (PBI-BC; Klimidis et al., 1992), with the aim of determining if the parents showed to be warm and supportive toward their children. This dimension includes the following items repeated for the mother and the father: “helps me as much as I need,” “is loving,” “understand my problems and worries,” and “makes me feel better when I'm upset.” An average score from 0, never, to 2, almost always, was obtained from this scale, with a Cronbach's alpha of 0.85. Level of measurement: continuous variable.
	Ease of communication with parents	Participants were asked: “how easy is it for you to talk to your father about things that really bother you?” and “how easy is it for you to talk to your mother about things that really bother you?” (these questions were created by the HBSC study). An average score on ease of communication with parents was obtained that ranged from 1, very difficult, to 4, very easy. Level of measurement: ordinal variable.
	Satisfaction with family relations	This variable was measured by means of an item based on Cantril's Ladder (1965): “in general, how satisfied are you with the relationships in your family?” A quantitative score was obtained that ranged from 0 “we have very bad relationships in our family” to 10 “We have very good relationships in our family.” Level of measurement: quantitative variable.