Obesity--a growing issue.

OBJECTIVES This article, based on longitudinal data, follows a sample of people who were aged 20 to 56 in 1994/95 to determine the percentage who made the transition from normal to overweight, or from overweight to obese by 2002/03. Characteristics that increased the chances of overweight people becoming obese are examined. DATA SOURCES The data are from five cycles of the National Population Health Survey, 1994/95 through 2002/03. ANALYTICAL TECHNIQUES Cox proportional hazards modelling was used to identify variables associated with an increased or decreased risk of becoming obese; 1,937 men and 1,184 women who were overweight in 1994/95 were selected. MAIN RESULTS Close to a third (32%) of people who were aged 20 to 56 and of normal weight in 1994/95 had become overweight by 2002/03. During the same period, almost a quarter of those who had been overweight in 1994/95 had become obese. Among people who were overweight, the risk of obesity was relatively high for younger men and members of low-income households. Overweight men who smoked or who had activity restrictions had a high risk of obesity. Physical activity helped women avoid obesity.