Several anthropometric measurements were studied for their prediction of scoliosis in 896 children (430 girls and 466 boys) who were free from scoliosis at entry. The children were examined annually from the average age of 10.8 to 13.8 years to follow up their trunk asymmetry, posture, and growth. Scoliosis developed in 24 boys and 41 girls (Cobb angle > or = 10 degrees in a posteroanterior standing radiograph) during the 3 years. In both girls and boys, trunk asymmetry measured by the forward bending test was found to be the most powerful determinant of the incidence of scoliosis. In the whole cohort the adjusted odds ratio was 1.61 and its 95% confidence interval was 1.42-1.82 per one millimeter increase in trunk hump. Using spinal pantography the degree of thoracic kyphosis in girls (odds ratio = 1.05, 95% confidence interval = 1.01-1.09, per one degree) and the degree of lumbar lordosis in boys (odds ratio = 1.07, 95% confidence interval = 1.01-1.13, per one degree) were significant predictors of future scoliosis. In the children both sexes who eventually had scoliosis, body height, sitting height, and growth of sitting height were greater than in other children, but these factors carried no statistical significance in the logistic analyses. There were differences between the prescoliotic girls and other girls in both mean age (11.8 vs 12.1 years, P = 0.02) and value (5.5 cm vs 6.1 cm/yr, P = 0.08) of peak sitting height velocity.(ABSTRACT TRUNCATED AT 250 WORDS)