Influence of catch-up growth on glucose tolerance and beta-cell function in 7-year-old children: results from the birth to twenty study

The aim of this study was to investigate the effect of catch-up growth occurring at different stages of childhood on glucose levels and beta-cell function at 7 years of age. Oral glucose tolerance tests were performed on 152 7-year-old children. Anthropometric data were available from birth to 7 years of age. Children were split into catch-up, catch-down, and normal-growth groups on the basis of growth rates between birth and 1 year, birth and 5 years, and birth and 7 years. Fasting and 30- and 120-minute blood samples collected during the oral glucose tolerance tests were assayed for glucose, insulin, proinsulin, and des-31,32-proinsulin levels, and area-under-the-curve values were calculated. Children with catch-up growth between birth and 5 years or birth and 7 years had greater area-under-the-curve insulin levels than the children with catch-down growth. Children with catch-up growth only between birth and 7 years exhibited higher proinsulin levels and a greater insulin secretory response to glucose than those who experienced catch-up growth between both birth and 1 year and birth and 7 years of age. Low birth weight children with no catch-up growth between birth and 7 years had the highest glucose and lowest insulinogenic index levels, whereas children with high birth weight and catch-up growth had the highest insulin levels. Extremes of birth weight in conjunction with extremes of postnatal growth are all detrimental to childhood metabolism. The negative metabolic effects of catch-up growth between birth and 7 years may be attenuated if catch-up growth also occurs between birth and 1 year of age.