This survey presents data on the height, weight and body mass index of a nationally representative sample of children aged 4–16 years in the Republic of Ireland and Northern Ireland. Using international norms, overall, almost one in four boys (23% RoI and NI) and over one in four girls (28% RoI, 25% NI) were either overweight or obese. While not significant, higher rates of overweight and obesity were seen in the Republic of Ireland compared to Northern Ireland.
Current data in Ireland from the recent National Health and Lifestyle Survey, SLÁN indicate that between 1998 and 2002 obesity rates in adults rose by 3% and Health Behaviours in School Children (HBSC) figures indicate that 14% of 13 year old boys and 10% of 13 year old girls are either overweight or obese . Both of these studies are based upon self reported heights and weights. To date however, no data were available to allow a North-South comparison in Ireland. The pattern of overweight and obesity found in this survey (2002) is very similar to that observed in the Health Survey for England 2002 . In the latter survey, according to IOTF criteria, 6% of boys and 7% of girls aged 2–15 were obese and 22% of boys and 28% of girls were either overweight or obese. In Ireland in 2002, almost one in four boys (23% RoI and NI) and over one in four girls (28% RoI and 25% NI) were either overweight of obese. Had the UK 1990 cut-off points of the 91st and 98th centile, for overweight and obesity respectively, these figures are substantially higher.
A novel aspect of the research is that it is the first all Ireland study in which the height and weight of a representative sample of children has been measured contemporaneously, north and south of the border, using standardised criteria. The study, is the largest of it's kind estimating the prevalence of overweight and obesity amongst school-aged children in Ireland to date (n = 19,617). There was a good response rate particularly for the Republic of Ireland, 68% and 53% Northern Ireland, allowing confidence that the estimated prevalence rates are reliable. However, surprisingly, there was no significant variation in prevalence across social groups in either RoI or NI. The measure of socioeconomic status recorded for this study was the possession of a General Medical Services (GMS) Card in RoI and those in receipt of Low Income Benefits (LIB) in NI. It is probable that a more significant variation in prevalence of obesity among school-aged children across the island of Ireland would be seen with a more complete measure of socio-economic status. Additionally, the difference in the response rate between RoI and NI requires us to interpret the North-South difference with caution.
The extent to which non response bias has affected these results is unclear. However, one could assume that if subjects were likely to refuse consent for the study on the basis of weight, they would probably be overweight subjects. This would result in an underestimate of overweight and obesity. The fact that this was primarily a dental survey and that assurances of privacy and confidentiality were given in the consent form is likely to have minimised non response due to embarrassment as a result of overweight. The same challenges are faced by other similar studies and these challenges are difficult to overcome.