The frequencies of social support items were categorized into never, occasionally, and often, and rated as 1, 2, and 3, respectively; satisfaction with social support was rated 1 if unsatisfied, 2 if did not matter, and 3 if satisfied.
Scaling questions to measure the frequency or magnitude of significance had three prespecified levels (never, occasionally, and frequently or none, minor, and major, respectively).
The five categories for drinks such as coffee and tea were: almost never, occasionally, 1 2 cups per day, 3 4 cups per day, and ⩾5 cups per day.
Numeric values for levels were designated rather than ordinal values (e.g. never, occasionally and often) so that respondents would interpret each level in the same way.
A 5-point scale provided the answers: "Don't know", "Never", "Occasionally", "Frequently", and "Always" with the scores of 0, 1, 2, 3, and 4 respectively (see Additional file 2).
For green tea and coffee, the five categories were almost never, occasionally, 1 2 cups/day, 3 4 cups/day, and more than 5 cups/day.
Each question has four possible answers that were scored from one to four (never, occasionally, frequently, and always).
Questions related to ICU workers' perceptions about an OVP presented four possible answers: never, occasionally, frequently, and always.
Maternal smoking in pregnancy was documented in three categories (never, occasionally or regularly) and dichotomised to never or any.
Each item was assessed on a 5-point Likert scale (never, occasionally, sometimes, often, and always).
Table 3 shows the sociodemographic and other characteristics of children who were never, occasionally, or frequently victimised at age 13 years.
