Association between Changes in Menarcheal Age and Adolescent Idiopathic Scoliosis: An Analysis of 38,879 Patients over 20 Years.

Backgroud: Menarche has a significant impact on the progression of adolescent idiopathic scoliosis (AIS); however, studies in this area are insufficient. This study used large-scale school screening data to investigate the relationship between menarcheal age and AIS, especially the severity of scoliosis.

Methods: Of 2,326,577 students who participated in school screening for scoliosis (SSS) in South Korea from 2001 to 2021, 38,879 girls with AIS, who experienced menarche, were included. Data including the patient's demographics, such as menarcheal age, Cobb angle, Risser stage, and the interval between menarche and the time of screening were retrieved from the SSS database. Pearson correlation coefficient was used to identify the changes in menarcheal age according to the birth year and to investigate the relationship between menarcheal age and each variable of interest.

Results: Based on the birth year, the mean menarcheal ages in girls with AIS from 1988 to 2008 demonstrated a steadily decreasing trend over time (r = -0.857, p < 0.001). Girls with AIS and late menarche demonstrated a higher Cobb angle at the time of screening (r = 0.095, p < 0.001). Other variables did not significantly correlate with menarcheal age.

Conclusions: Based on the SSS, a large-scale school screening dataset, menarcheal age in girls with AIS demonstrated an ongoing downward trend in the recent 20 years in South Korea. Notably, girls with AIS and late menarche had a higher Cobb angle at screening. Our findings indicate the need for earlier screening of AIS in girls who have not undergone menarche.