Potential correlates of temporal trends in CRF in children and adolescents
| Variable | Data source | Description |
| Overweight/obesity (%) | Ng et al
30 Trend data available for 19 countries between 1990 and 2013. | Calculated as the change (per decade) in mean country-specific percentage of boys and girls aged 2–19 years (age standardised) that classified as overweight and/or obese based on the International Obesity Task Force definition. A positive change indicated an increase in the mean percentage of overweight/obese and a negative change indicated a decline. |
| Physical activity (%) | Inchley et al
31 Data originally obtained from Health Behaviour in School-aged Children WHO collaborative cross-national study. Trend data available for 12 European countries between 2002 and 2014. | Calculated as the change (per decade) in mean country-specific percentage of boys and girls aged 11, 13 and 15 years old that achieved at least 1 hour of moderate-to-vigorous physical activity per day. A positive change indicated an increase in the mean percentage of physically active children and a negative change indicated a decline. |
| Gini index | The World Bank32 Trend data available for 18 countries between 2000 and 2014. | Summarises the change (per decade) in the distribution of income among individuals in a country where 0 represents perfect equality and 100 implies perfect inequality. A positive change indicated a trend towards perfect inequality and a negative change a trend towards perfect equality. |
CRF, cardiorespiratory fitness.