Prevalence of overweight and obese children between 1989 and 1998: population based series of cross sectional studies

Abstract Objective: To determine trends in weight, height, and body mass index in children between 1989 and 1998. Design: Retrospective series of cross sectional studies of routinely collected data. Setting: Primary care in the Wirral Health Authority. Participants: 35 662 infants aged 1-3 months (representing 88% of live births) and 28 768 children aged 2.9-4.0 years. 21 582 infants and children (25.1%) were excluded because of missing or inaccurate data. Main outcome measures: Weight, height, sex, and age routinely recorded by health visitors. Height, weight, and body mass index standardised for age and sex. SD score >1.04 for body mass index (>85th centile) was defined as overweight and >1.64 (>95th centile) as obese. Body mass index was not calculated in infants as it is difficult to interpret. Results: From 1989 to 1998 there was a highly significant increasing trend in the proportion of overweight children (14.7% to 23.6%; P<0.001) and obese children (5.4% to 9.2%; P<0.001). There was also a highly significant increasing trend in the mean SD score for weight (0.05 to 0.29; P<0.001) and body mass index (−0.15 to 0.31; P<0.001) but not height. Infants showed a small but significantly increasing trend in mean SD score for weight (−0.17 to −0.05; P=0.005). Conclusions: From 1989 to 1998 there was a highly significant increase in weight and body mass index in children under 4 years of age. Routinely collected data are valuable in identifying anthropometric trends in populations.