• PHYSICAL ACTIVITY
• Life course epidemiology
• SOCIAL INEQUALITIES

As societies change, so do the most apparent modifiable determinants of health. Since televisions first became commercially available earlier in the 20th century, they are now owned by the majority of households and increasing amounts of time are spent watching television. A growing body of evidence shows links between greater time spent watching television and increased risk of ill health.1 ,2 Despite its positive potential (eg, in information dissemination), watching television is typically sedentary, and is therefore likely to tip energy balance in favour of fat accumulation. In addition, it displaces time spent in health-benefiting behaviours, exposes users to food advertising, and may be done alongside other damaging behaviours such as snacking. There are therefore considerable potential public health benefits of reducing television viewing and replacing it with healthier pursuits. Understanding its determinants would aid this—the paper by Smith et al3 contributes to this by examining the childhood correlates of adult television viewing in the 1970 British birth cohort study.

Smith et al found evidence that television viewing tracks from childhood (age …