THE NATURAL-HISTORY OF IDIOPATHIC SCOLIOSIS - INCIDENCE OF TREATMENT IN 15 COHORTS OF CHILDREN BORN BETWEEN 1963 AND 1977

Study Design. This study analyzed the incidence of treatment of scolio sis using a cross-sectional and a longitudinal technique. Objectives. To follow the incidence of treated scoliosis in Malmo, Sweden, in chil dren born between 1970 and 1977 and compare observations with those of a study from 1988, in which the incidence of this disorder was follow ed in children born between 1963 to 1969. Summary of Background Data. During the late 1970s and early 1980s, the incidence of treated scolio sis decreased yearly in Malmo. This trend was supported by other repor ts. However, introduction of worldwide screening for scoliosis was a c onfounding factor. When cohorts of children born between 1963 and 1969 were analyzed, no change was found. In a study in Malmo in 1988, this was shown to be an effect of using a longitudinal instead of a cross- sectional technique of analyzing the data. Methods. In a cross-section al study, the authors registered all new treatments for idiopathic sco liosis, brace treatments, or direct surgery, for each year between 198 4 and 1993. In a longitudinal study, all new treatments in each cohort of children born between 1970 and 1977 were followed. The results wer e compared with figures from the 1988 study. Results. After the introd uction of school screening in 1976, a peak in the incidence of treated scoliosis was seen in 1977. After a continuous decrease in the incide nce until 1983, a steady state developed. In cohorts horn between 1963 and 1977, the incidence is neither increasing nor decreasing. Conclus ions. In cohorts of children followed in a longitudinal study over a 1 5-year period (born between 1963 and 1977), there is no support for a change in the natural history of idiopathic scoliosis.