Aim: Since obesity is thought to be an aetiological factor for SCFE we have looked to see if the ‘Obesity epidemic’ in children has been associated with a similar trend in SCFE.

Method: A population based study, using a national database of NHS Scotland activity, was undertaken to analyse trends in SCFE from 1981 to 2005 and to look for a relationship with changes in obesity in Scotland. Data on the body mass indices of Scottish school children have been collected as part of the child Health Surveillance Programme.

Results: We found that the incidence of SCFE increased from 3.78 per 100,000 children in 1981 to 9.66 per 100,000 children in 2000 (R² = 0.715) – a two and a half fold increase over two decades. Furthermore, SCFE was seen at younger ages with a fall in the average age at diagnosis from 13.4 to 12.6 years for boys (p=0.007) and 12.2 to 11.6 for girls (p=0.047). SCFE is rare in young children – for 1981–1990 only two children presented with the diagnosis between the ages of six and eight; however for 1991–2000 seven presented in this age group. Along with the rest of the UK, the two decades we studied had seen markedly rising childhood obesity rates in Scotland. The prevalence of overweight (BMI> 85^th centile) 13–15 year old children doubled from 15% in 1981 to 29% in 2001 and the problem extends to 4 and 5 year olds, although it is not of the same severity.

Conclusion: The incidence of SCFE has increase two and a half times in two decades and may well be a consequence of the worsening obesity rates that have occurred over the same period.