Adolescent idiopathic scoliosis (AIS) is a condition characterized by asymmetrical spinal rotation. As the word “idiopathic” in its name suggests, the etiology of AIS is still unknown, which makes early intervention and treatment difficult, despite the large amount of research done by scholars, and epidemiological studies of AIS can help people to further understand the developmental pattern of AIS. In this paper, we will summarize the progress of epidemiological research on AIS in terms of its distribution pattern, risk factors, early screening, and prognosis. Distribution pattern 1, Incidence: despite the fact that a large number of epidemiologic surveys have been done, the statistical results of the incidence of AIS are not the same. The main reasons for this include differences in the means and targets of screening, as well as the adoption of different diagnostic criteria. If Cobb angle >5° is used as the criterion, the prevalence rate is about 5-15%; if Cobb angle >10° is used as the criterion, it is about 1.5-3%; if Cobb angle >20° is used as the criterion, it is about 0.3-0.5%; and if Cobb angle >30°, it is about 0.2-0.3%. At present, people have tended to take Cobb angle >10° as a unified standard, therefore, it can be assumed that the prevalence of AIS is about 1.5-3%. 2. Male-to-female ratio: Soucacos et al. conducted a mass screening of 82,901 children aged 9-14 years, and among the 1,436 AIS patients screened, the total male-to-female ratio of AIS was approximately 1:2.1. However, as the angle of scoliosis increases, the male-to-female ratio will continue to change: with a curvature of less than 10°, the male-to-female ratio is 1: 1.5; from 10 to 19°, it is 1: 2.7; from 20 ～For curvature less than 10°, the male:female ratio is 1:1.5; for 10-19°, it is 1:2.7; for 20-29°, it is 1:7.5; for 30-40°, it is 1:5.5; and for curvature >40°, it is 1:1.2. Distribution of curvature: Soucacos et al. showed that curvature of 10-20° was the most common curvature of AIS, accounting for about 90% of all patients. Curvature greater than 20° accounted for about 9.3%, while less than 2% were greater than 40°. 4. Racial and familial distribution: Two studies by Carter et al. and Shands et al. attempted to look for differences in the racial distribution of AIS between whites and blacks in the U.S., but no significant differences were found.Segil et al. conducted a comparative study of the Bantu versus the Johaberg ethnic groups and found that the distribution of AIS was significantly lower in the Bantu ethnic group. A screening study in a Singaporean secondary school found that Chinese girls aged 11-12 and 16-17 years had significantly higher rates of scoliosis than Malay Peninsula and Indian girls of the same age. In addition, an epidemiologic survey of recruits in Israel found significantly lower rates of scoliosis among soldiers with parents of Moroccan origin and significantly higher rates among soldiers with parents of Iraqi and Western European origin. Ratahi ED et al. showed that the number of scoliosis in the European group exceeded the expected number of scoliosis, whereas the number of scoliosis in the Polynesian (Māori and Mid-Pacific Islands) group was lower than the expected number of scoliosis. 5. Epidemiologic investigations have shown that there is a familial clustering of AIS. an early study by Harrington followed women with scoliosis over 15 degrees and found that the prevalence of scoliosis in their daughters was about 27%. riseborough and Wynne investigated 207 patients and 2,662 familial relatives and found that the prevalence in first-degree relatives was 11%; 2.4% in second-degree relatives; and 1.4% in third-degree relatives. Studies of twins suggest that the concordance rate (i.e., the chance of both having AIS) for monozygotic twins is as high as 73%, while the nonconcordance for dizygotic twins is 36%. Risk Factors A long-term follow-up study has shown that the curvature progresses in about 6.8% of patients with AIS. If one is able to determine the degree of risk for scoliosis, one is able to apply bracing or surgical treatment for early aggressive intervention and can significantly improve the prognosis of the disease. A great deal of work has been done in this regard. The results suggest that the following factors are closely related to the progression of AIS. 1. Gender and age: Female patients are significantly more likely to have scoliosis progression than male patients. Several studies have shown that the risk of scoliosis progression in women is approximately 10 times higher than in men. A recent study suggests that the gender difference in scoliosis progression is most significant when the size of scoliosis progression is 5-9°/year. (Females 54.5%; males 9.8%) Sex differences in scoliosis progression have also been investigated at the molecular level.Inoue et al. followed 304 girls with AIS and found that: polyphenism at the X chromosome locus was associated with scoliosis progression. Patients with genotypes XX and Xx had a significantly higher risk of needing surgical intervention than those with genotype xx. Patients with genotypes XX and Xx were also significantly more likely to have skeletal maturity than those with genotype XX. (Skeletal maturity is also a risk factor for progression of scoliosis in AIS, as will be discussed later.) The relationship between the risk of scoliosis progression and age has been confirmed by many studies. In the study by Soucacos et al, they found that both males and females showed a small discernible peak in the progression odds curve at the peak of pubertal development. The age of risk for females is 11 to 12 years; for males it is around 14 years. Duval’s study examined AIS progression and seven parameters that may be associated with it, and the results confirmed these studies, but found no correlation between the rate of scoliosis progression and age. 2. Growth potential: Scholars believe that the greater the growth potential, the greater the risk of scoliosis progression. Therefore, indicators of maturity (Tanner class, menarche, Risser class) can be used to predict the risk of scoliosis progression. a study by Lonstein et al. found that in patients with scoliotic angles <20°< span="">, the chance of scoliosis progression in immature patients (Risser class 0 and 1) was 22%, whereas in mature patients it was only 1.6%; in patients with scoliotic angles of 20°< span="">, the chance was only 1.6%; in patients with scoliotic angles of 20°< span="">, the risk was only 1.6%. In patients with scoliosis of 20 to 29°, 68% of immature patients had a progression of scoliosis compared with 23% of relatively mature patients (Risser grades 2 to 4), and a large-scale survey by Soucacos et al. showed that only 35.6% of female patients with progression of scoliosis had a menstrual period, compared with 35.6% of female patients who had improved naturally or whose scoliosis had remained stable. In contrast, the rate of menstruation was 52.3% in female patients with natural improvement or stable curvature. Nature of scoliosis: This includes the size of the scoliosis, the type of scoliosis, and the direction of the scoliosis. Epidemiologic studies suggest that the size of the scoliosis angle is closely related to its risk of progression. The larger the angle, the greater the risk of progression. After spinal maturation, scoliosis with a curvature <30°< span=""> hardly progresses; whereas patients with AIS with a scoliosis of 30-50° progress an average of 10-15° during their lifetime; and patients with a scoliosis of 50-75° progress at an average rate of about 1° increase per year. Lateral curvature angles >100° may be life-threatening with severe compromise of lung function. It has been found in studies that the chance of progression of the curvature varies with the type of scoliosis. As an example of common types of scoliosis: double bends have the highest chance of progression (21%), followed by thoracic bends (16.9%), lumbar bends (14.3%), and finally thoracolumbar bends (10.1%). et al. screened 85,627 adolescents between the ages of 9 and 15 years and followed up the patients with scoliosis among them for 2.5 to 4 years. The results found that all patients with left-sided thoracic curvature did not show progression during the follow-up period; whereas the odds of progression in right-sided thoracic curvature were as high as 22% (lateral curvature angle of 10-19°). The correlation between the direction of lateral curvature and the progression of AIS curvature needs to be confirmed by further studies. 4. Comprehensive evaluation: As mentioned earlier, the progression of AIS curvature is associated with a number of factors, including gender, curvature size, and skeletal maturity. Epidemiologic studies suggest that scoliosis improves naturally in 3% of AIS patients; 2.75% of patients require therapeutic intervention. In this study, a table of critical values for the three main indicators of the risk of progression of scoliosis (Cobb’s value when lying down, upright Cobb’s value, and rib augmentation) was statistically established. Depending on the different types of scoliosis and skeletal maturity of patients with scoliosis, the corresponding critical values can be accessed in this table. The investigators concluded that if the three main indicators are below the thresholds recommended in the literature in patients with AIS, only the necessary monitoring is required. If, at the first examination, all three thresholds are exceeded in patients with AIS, the risk of scoliosis progression is significantly higher and the scoliosis angle will increase linearly. The limitations of this study are the small sample size of 346 patients and the exclusion of patients younger than 4 years of age, and its conclusions need to be further confirmed by a large sample study. Current status of screening Screening is considered a secondary prevention tool for AIS. It aims to identify patients with AIS as early as possible before symptoms of AIS become apparent, thereby guiding further definitive diagnosis and early intervention as necessary. The means of screening have evolved from the initial physical examination and the Adams forward bend test to high-tech screening tools such as ultrasound real-time linear array scanning and photoelectric circular scanning. To date, the four most prominent global screening methods include the Adams forward bending test, measurement of trunk rotation with a scoliometer, Moire’s localized measurement, and measurement of rib augmentation. Epidemiologic studies have shown that the Adams forward bending test has a sensitivity of 84.37% and a specificity of 93.44%, the Moire localization method has a sensitivity of 100% and a specificity of 85.38%, the rump gauge has a sensitivity of 93.75% and a specificity of 78.11%, and the scoliometer has a sensitivity of 90.62% and a specificity of 79.76%. …… Accordingly, scholars have concluded that the Adams forward bending test is unsafe as a primary screening tool for AIS. Some scholars have suggested using scoliometer as the primary screening tool, supplemented by the Adams forward bending test to ensure the sensitivity and specificity required for screening. The main problem facing screening at present is the false positive results it produces, which may give rise to unnecessary or erroneous human intervention. Many large-scale school screening trials have identified this problem. This will be the direction of future research. In addition, the unnecessary radiation exposure and psychosocial stress brought about by screening have also been brought to the attention of scholars. Healing 1. Mortality: Although early studies concluded that the mortality rate of AIS patients was significantly higher than that of the comparison group, however, these studies included patients with congenital scoliosis, neuromuscular scoliosis, and scoliosis associated with known etiologies, such as Marfan’s syndrome, trauma, and so on, which affects the accuracy of the findings. It is now recognized that individual mortality in AIS is essentially the same as in the normal population. 2. Back pain and changes in pulmonary function: Weinstein’s study showed that 77% of scoliosis patients had acute back pain, compared to 37% of the comparison group, and 61% of scoliosis patients had chronic back pain, compared to 35% of the comparison group, which is statistically significant. Several studies have demonstrated a direct correlation between the size of the scoliosis angle and lung function only in patients with AIS whose scoliosis type is thoracic. As the angle of lateral curvature increases, spirometry and first-second expiratory expiratory output with exertion, as well as arterial partial pressure of oxygen, will decrease. However, no studies have found a correlation between scoliosis angle and decreased lung function in other forms of scoliosis. 3, psychosocial factors: AIS-induced psychosocial changes have also received extensive attention from scholars. In an earlier study by Kahanovitz et al, patients treated with braces showed more anxiety, depression, uncooperativeness, and a tendency to avoid problems compared to patients treated with electrical stimulation.Clayson’s study found that scoliosis patients showed a greater lack of self-confidence and a low level of acceptance of their own body type compared to the comparison group. In addition, many studies have concluded that: the protrusion of the ribs and the imbalance of the paravertebral muscles may make the rotation of the trunk more pronounced. These changes may not be evident on imaging, but they can affect the patient’s image of appearance, which can cause psychological disorders in the patient. 4. Quality of life: One study found that 19% of patients with scoliosis angles >40 degrees had severe psychological disorders. Problems such as social isolation, limited job opportunities, and low marriage rates. Another long-term study confirmed that patients with AIS were significantly limited in physical activity compared to a comparison group of the same age, mainly due to dysfunction and long-standing back pain. Among patients treated with braces, physical activity limitations were more pronounced compared to those who did not receive braces. Conclusion Numerous epidemiologic studies of AIS have shown that the prevalence of AIS ranges from approximately 1.5 to 3%; it occurs more frequently in women; the most common curvature is 10-20°; scoliosis improves spontaneously in 3% of patients with AIS; and therapeutic interventions are required in 2.75% of patients.There may be a certain familial and racial clustering of AIS. Risk factors for exacerbation of scoliosis include: gender-female; age-female 11 to 12 years, male about 14 years; growth potential-adolescent Risser grade 0 to 1 or non-menstruating girl; angle of scoliosis >30°; and type of scoliosis-bi-bend or thoracic bend. Double bend or thoracic bend. Based on current epidemiologic studies, the use of screening for early diagnosis and secondary prevention of AIS has been questioned. This is mainly based on the following reasons: 1) Only 2.75% of patients require therapeutic means of intervention. 2) The Adams forward bending test as a screening criterion has been found to be unsafe and unreliable. 3) Screening induces false positive results and thus artificial over-intervention. 4) To date, the natural history of AIS and the efficacy of non-surgical treatments remain poorly understood. 5) Screening has been shown to be effective in the treatment of AIS. 6) Screening has been shown to be effective in the treatment of AIS. The mortality rate is comparable to that of the normal population. Threshold values for three major indicators associated with the risk of curvature progression have been established to evaluate the risk of AIS development and to guide individualized interventions for it. the psychosocial abnormalities and the decline in quality of life triggered by AIS have also been demonstrated. Although the etiology of AIS has been extensively studied from the perspectives of genetics, molecular biology, and histochemistry, there is still no conclusive evidence for any of the hypotheses. In-depth epidemiologic studies will further reveal the pathogenesis and developmental patterns of AIS, which will lead to more effective and rational early human intervention and more significant improvement in the prognosis of AIS.