A ®ve-year trend of increasing obesity among elementary schoolchildren in multiethnic, low-income, inner-city neighborhoods in Montreal, Canada J O'Loughlin 1,2 *, G Paradis 1,2 , G Meshefedjian 1 and K Gray-Donald 3 1 Department of Public Health, Re Âgie re Âgionale de la sante  et des services sociaux de Montre Âal-Centre, 1301 rue Sherbrooke Est, Montreal, Quebec, Canada H2L 1M3; 2 Department of Epidemiology and Biostatistics, McGill University, Purvis Hall, 1020 Pine Avenue West, Montreal, Quebec, Canada H3A 1A2; and 3 Department of Dietetics and Human Nutrition, McDonald Stewart Building, MacDonald College, 21,111 Lakeshore Drive, Ste-Anne-de-Bellevue, Quebec, Canada H9X 3V9 OBJECTIVE: To describe the prevalence of overweight and obesity over 5 y among inner-city elementary school- children aged 10 ± 12 y in multiethnic, low-income neighborhoods in Montreal, Canada. DESIGN: Height and weight of all students in grades 4 ± 6 in 16 control schools participating in an evaluation of the impact of a school-based heart health promotion program, were measured each May=June from 1993 to 1997 in cross- sectional classroom-based school surveys. RESULTS: The prevalence of overweight (  85th age- and gender-speci®c percentile for body mass index (BMI) from NHANES I and II) was 35.9% in 1993; it increased by approximately 1.3% per year. The prevalence of obesity (  95th age- and gender-speci®c percentile for BMI from NHANES I and II) was 15.9% in 1993; it increased by approximately 1.0% per year. In multivariate models predicting overweight and obesity, the odds ratios for year adjusted for age, sex, and family ethnic origin were 1.08 (95% con®dence interval (CI), 1.04 ± 1.12), and 1.09 (95%CI, 1.04 ± 1.15), respectively. CONCLUSION: There were signi®cant secular trends of increasing overweight and obesity among young inner-city schoolchildren from the early to late 1990s. Preventive intervention is clearly indicated because childhood obesity tracks to adulthood and because obesity is associated with substantial morbidity, mortality and health care costs. International Journal of Obesity (2000) 24, 1176±1182 Keywords: obesity; child; low income; ethnicity; trend; prevalence Introduction Marked increases in the prevalence of overweight and obesity have been observed in the last quarter century in both adults 1,2 and children, 3±7 raising considerable concern over likely increases in obesity-related mor- bidity and mortality, as well as increased health care costs associated with obesity-related illness. 8 Numer- ous reports document time trends in the prevalence of obesity in children up to the early 1990s, but there are as yet few reports which describe the prevalence from the early to late 1990s among children. Also there are few studies of low-income children in whom the secular trends of increasing obesity appear to be more marked. 9,11 In this report, data from the evaluation of a school- based heart health promotion program, Coeur en sante  St Louis du Parc, were used to describe the yearly prevalence of overweight and obesity among pre- adolescent children over a 5 y period from 1993 to 1997. Earlier reports 12,13 documented a high preva- lence of overweight and obesity in this study popula- tion from low-income, ethnically diverse, inner-city neighborhoods in Montreal, Canada. Methods The study design for the Coeur en sante  St Louis du Parc intervention study has been described in previous reports. 12 ± 16 Brie¯y, data to evaluate the impact of the program on student smoking, dietary and physical activity behaviors were collected in classroom-based surveys conducted each May=June from 1993 to 1997, from all grade 4, 5 and 6 students for whom informed parental consent had been obtained, in eight interven- tion and 16 comparison schools. All schools were in the lowest quartile of a school-speci®c composite poverty index used by the Montreal Island School *Correspondence: J O'Loughlin, Department of Public Health, Re  gie re  gionale de la sante  et des services sociaux de Montre  al- Centre, 1301 rue Sherbrooke Est, Montreal, Quebec, Canada H2L 1M3. E-mail: joloug@po-box.mcgill.ca Received 22 November 1999; revised 3 April 2000; accepted 20 April 2000 International Journal of Obesity (2000) 24, 1176±1182 ß 2000 Macmillan Publishers Ltd All rights reserved 0307±0565/00 $15.00 www.nature.com/ijo