To the Editor: The interesting article on playground safety and arm fractures by Sherker and Ozanne-Smith1 documents a steady increase in hospitalisation rates for arm fractures among Victorian children between 1987 and 2002. It would appear that the increase over this 15-year period was about 45%. These figures may represent the tip of the iceberg, as few children with arm fractures are admitted to hospital and most are treated on an outpatient basis. Increases of similar magnitude in forearm fractures in adolescence have also been reported recently in the United States.2 It would seem that children are becoming more vulnerable to such fractures. This is a concern, as fractures of the distal forearm are extremely common during growth. Indeed, about a quarter of all fractures during childhood and adolescence occur at this site.

One factor that might be contributing to this rising incidence of arm fractures during growth is increasing childhood adiposity. Childhood obesity has increased sharply in Australian children over recent years.3 Obese children fall with more force, and, although they may have more bone for chronological age than children of healthy bodyweight, adaptive increases in bone mass are not enough to accommodate their high bodyweight gain, placing them at a biomechanical disadvantage during falls on the outstretched arm.4 Our studies of consecutive series of girls and boys with distal forearm fractures indicate that a high proportion of these children are overweight. Moreover, in a 4-year prospective study of 170 girls, we found that high bodyweight at baseline increased the risk of new fractures.5

In their study, Sherker and Ozanne-Smith measured the heights and weights of 402 children under 13 years of age who had broken their arm falling from playground equipment between 2000 and 2002. We wonder how many of these children were overweight or obese for their age. Examination of the body mass index values would provide this information, and we ask that the authors report these data for both girls and boys using international cut-off points. We would like to know whether or not overweight is contributing to rising rates of arm fracture in Australian playgrounds.

In reply: The prevalence of obesity has increased dramatically among Australian children, particularly over the past 2 decades.1 However, the role of obesity as a risk factor for fall-related arm fracture remains unclear. Using standard definitions for child overweight and obesity,2 our study population3 (Box) did not demonstrate quite as high a prevalence of obesity as had been previously reported for Victorian schoolchildren.1

This case series was part of a larger, yet to be published case–control study, the results of which indicate no significant difference in body mass index between children who fell from playground equipment and fractured their arm (cases) and those who fell and landed on their arm with no significant injury (controls).

The negative public health effects of increasing prevalence of obesity among Australian children highlight the need to promote safe and enjoyable physical activity. Playground equipment provides a very popular means of physical activity for children. Improving playground safety standards to minimise the risk of arm fracture — a traumatic, costly and preventable childhood injury — has never been more urgent.

Children with arm fracture caused by falls from playground equipment, showing proportion of children who were normal weight, overweight or obese.*

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* Based on unpublished data from Sherker and Ozanne-Smith.3