Scoliosis is indeed a complex three-dimensional deformity of the spine, characterized by vertebral rotation and imbalances in the coronal, sagittal, and axial planes. It can be broadly categorized into idiopathic scoliosis (IS) and non-idiopathic scoliosis (Non-IS) (1).

Both the musculoskeletal and circulatory systems originate from the mesoderm, with numerous genes and signaling pathways collaboratively regulating cell differentiation and organ development in these systems (2–6). Environmental factors, such as hypoxia during pregnancy, vitamin deficiencies, alcohol consumption, and maternal diabetes, have also been implicated in the co-occurrence of scoliosis and congenital heart diseases (CHD) (7–10). These two developmental processes are interconnected: the hypoxia environment in patients with cyanotic congenital heart disease may serve as a risk factor for the onset and progression of scoliosis (11). The interplay of these extrinsic and intrinsic factors likely contributes to the higher prevalence of congenital heart disease among scoliosis patients compared to the general population. Previous clinical studies have reported that the incidence of CHD in patients with idiopathic scoliosis (IS) ranges from 4.14 to 8.75% (12–14), while the incidence in patients with congenital scoliosis (CS) ranges from 6.95 to 26% (15). Investigating the relationship between these diseases can help uncover shared genetic variations and enhance our understanding of their common etiology. Furthermore, such research can improve the comprehensive management of patients, ensuring they receive holistic evaluation and treatment. By understanding the prevalence and influencing factors of these comorbidities, healthcare systems can better allocate resources and reduce long-term healthcare costs.

Previous studies have primarily focused on patients with severe scoliosis requiring surgical intervention, often conducted in hospital settings. However, there is a lack of population-based studies examining the incidence of congenital heart disease associated with scoliosis in children and adolescents. To address this gap, this study investigated and analyzed the prevalence of scoliosis and CHD among 17,134 primary school students in Jinghong City, Yunnan Province. The findings aimed to provide valuable insights for research and prevention strategies targeting scoliosis and CHD in children and adolescents.

The screening was conducted in Jinghong City, located in the Xishuangbanna Dai Autonomous Prefecture of Yunnan Province. Using a random number table method, 17,134 students from 20 primary schools were randomly selected from a total of 52 primary schools in the city. The inclusion criterion was all students aged 6–15 years in 20 primary schools included in this study, while the exclusion criteria were: (1) Unable to cooperate in completing Adam's forward bending test, cardiac auscultation or echocardiography examination, (2) Unwilling to participate in scoliosis screening or congenital heart disease screening.

Prior to the screening, detailed information about the screening process was communicated to teachers and students in the target schools. Informed consent was obtained from teachers, students and their parents. The study received approval from the Ethics Review Committee of the Second Affiliated Hospital of Kunming Medical University (PJ-2021-100) and the Ethics Review Committee of Fuwai Cardiovascular Hospital of Yunnan Province (IRB2017-BG-028).

The scoliosis screening team was composed of spine surgeons from our department, graduate students, as well as orthopedic surgeons and nurses from local hospitals. All personnel underwent standardized training based on the Chinese guidelines named “Screening of Abnormal Spinal Curvature in Children and Adolescents” (16). The Scoliosis Research Society (SRS), the American Academy of Orthopedic Surgeons (AAOS), and several relevant U.S. academic institutions have collectively endorsed that well-trained screeners conducting an effective scoliosis screening program can facilitate early detection of adolescent scoliosis. During the screening process, school-aged adolescents were assessed using the Adams forward bending test and the trunk rotation angle (ATR) measured with a scoliometer (17). A comprehensive evaluation was performed utilizing multiple methods, including visual inspection, Adam's forward bending test, and ATR measurement. Visual inspection focused on observing the child's posture, shoulder height, scapular symmetry, lumbar contour, iliac crest height, and the alignment of the spinous process line relative to the posterior midline. For Adams's test, subjects were instructed to bend forward at a 90° angle, with any asymmetry in the back indicating a positive result. ATR measurements were conducted for subjects who tested positive on either the Adams's test or visual inspection (Figure 1). An ATR of ≥5° was considered indicative of scoliosis, with severity graded as follows: Grade I (5° ≤ ATR < 7°), Grade II (7° ≤ ATR < 10°), or Grade III (ATR ≥ 10°) (16).

Congenital heart disease screening personnel consisted of doctors and sonographers from Fuwai Cardiovascular Hospital of Yunnan Province. All personnel were screened and trained according to the Handbook of Congenital heart Disease Screening for Children in Community (18). The diagnostic criteria and disease classification of congenital heart disease were referred to the “Diagnostic Criteria for Congenital Heart Disease” (19). The screening of congenital heart disease included initial screening and diagnosis. Cardiac auscultation was performed for all students in the primary screening. If there was no abnormality in the initial auscultation, it was negative. Subjects with a previous diagnosis of congenital heart disease were considered as the confirmed population and reported to the staff directly (Figure 1).

Demographic information such as gender, age, ethnicity, height, weight, school, and grade was collected. For scoliosis, ATR value, site of abnormality, and direction of the spinal curve were recorded. Diagnostic information for students with congenital heart disease was also collected.

Data analysis was performed using SPSS 27.0 software, with enumeration data described by the number of cases and detection rate. The detection rate was expressed as a percentage (%). The screening population was categorized based on gender, age, and ethnicity, and the detection rate between groups was compared using the χ² test. A significance level of P < 0.05 was considered statistically significant in all tests.

The prevalence of suspected scoliosis among primary school students in Jinghong area.

This study represents the first large-scale epidemiological investigation of suspected scoliosis prevalence and its influencing factors in Jinghong City, Southwest China. The prevalence of suspected scoliosis among students in Jinghong City was 1.74%, which was comparable to the 1.50% reported in a 2016 Brazilian study of children and adolescents aged 6–18 (20). However, this prevalence was higher than those reported in the United States (0.2%) (21) and Japan (0.87%) (22), yet lower than the rates observed in our team's 2021 screening of primary and secondary school students aged 6–18 in Dali Bai Autonomous Prefecture (23), as well as in other regions of China, such as Chongming, Wuxi, and Zhejiang (24–26).The relatively lower prevalence in Jinghong may be attributed to the study's focus on primary school students aged 6–10, who constitute ~65% of the screened population. Scoliosis occurring before the age of 10, termed early-onset scoliosis (EOS), has a reported annual incidence of 0.019% in Asian children under 10 years old (27). Additionally, the most common form of scoliosis, adolescent idiopathic scoliosis (AIS), typically progresses during adolescence, with incidence rates increasing significantly during this period. Adolescence generally occurs between ages 9–14 in girls and 10–15 in boys (28–30), which aligns with our findings of a notable increase in positive rates after age 10. Furthermore, altitude may play a role in scoliosis prevalence. While previous studies suggest that altitudes above 4,500 m are a risk factor for scoliosis (31), Jinghong City's average altitude of 552 m is significantly lower, potentially contributing to the observed lower prevalence.

Current research has established significant gender and age differences in scoliosis incidence. Although the initial screening positive rate does not equate to the true diagnostic rate of scoliosis, it remains a valuable epidemiological indicator. In this study, the incidence was 1.15% for males and 2.36% for females, with males exhibiting a significantly lower incidence than females, consistent with previous findings (20–26). Despite the study's focus on primary school students aged 6–15, the results align with the established trend of increasing scoliosis incidence with age within a specific range (23–26). The observed higher positive rate in certain age groups may be attributed to the relatively small sample size in this study.

The survey was conducted in Jinghong City, a region with a high proportion of ethnic minorities, predominantly the Dai and Hani ethnic groups. The data revealed a difference in the scoliosis positivity rate between the Han ethnic group and ethnic minorities, although this difference was not statistically significant (P = 0.057). This finding may be attributed to the relatively small sample size of certain ethnic groups participating in the screening or potential variations in genetic factors, socioeconomic status, lifestyle habits, and health awareness among different ethnic groups in the study area (32).

In summary, the prevalence of suspected scoliosis among primary school students was 1.74%, while the prevalence of congenital heart disease was 3.15‰ in Jinghong City, Yunnan Province. And the incidence of CHD in patients with mild suspected scoliosis was low and close to that in normal population. Patients with scoliosis combined with CHD may be more prone to sustained progression.