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research paper

Indian Pediatr 2020;57: 138-141

Prevalence of Congenital Heart Disease Amongst Schoolchildren in Southwest China

 

Shen Han 1,2, Chuan-yu Wei3, Zong-liu Hou3, Ya-xiong Li1,2, Yun-chuan Ding2,4, Xue-feng Guang2,5, Dong Huang1, Zhu-hui Na1,2, Wen-min Chen1,2 and Li-hong Jian G 6

From Departments of 1Cardiovascular Surgery, 3Central Laboratory, 4Ultrasound, 5Cardiology, Yan’an Affiliated Hospital of Kunming Medical University; 2Key Laboratory of Cardiovascular Disease of Yunnan Province; and 6First People’s Hospital of Yunnan Province; Kunming, Yunnan, China.

Correspondence to: Dr. Li-hong Jiang, First People’s Hospital of Yunnan Province, Yunnan, China. 157, Jinbi Road, Kunming 650000, Yunnan, China.
Email: [email protected]

Received: March 12, 2019;
Initial review: October 29, 2019;
Accepted: December 12, 2019.

 

 

 

 

Objective: To investigate the prevalence and risk factors of congenital heart disease in Yunnan, China which has diverse ethnic groups. Methods: This cross-sectional study enrolled 244,023 children from 2010 to 2015. To diagnose CHD, a conventional physical examination was used to screen suspicious cases, which were further confirmed by echocardiography. Results: A total of 1695 children were diagnosed with CHD. The estimated prevalence was 6.94%. Atrial septal defects were the most common cardiac abnormalities. A higher prevalence of CHD was observed with preterm birth, low birth weight, maternal age ³35 years, and high-altitude regions. The prevalence also showed differences between diverse ethnic groups. Conclusion: The prevalence of CHD in China may have ethnic differences.

Keywords: Altitude, Epidemiology, Ethnic group, Risk factor.



C
ongenital heart disease (CHD) is a major cause of non-infectious death among children [1]. CHD is a result of alterations of multifactorial origin that include genetic and environmental factors [2]. Since 2012, CHD has become the most frequent type of birth defect in China [3]. Yunnan is a remote and underdeveloped southwestern province of China with an area of 394,000 km2. Furthermore, it is one of the most geographically and ethnically diverse places in the world, with over 26 different ethnic groups, and approximately 90% of the area is mountainous with altitudes ranging from 40 to 6000 m. The study was conducted to collect epidemiological data and risk factors of CHD in schoolchildren (aged 3-18 years) in Yunnan.

Methods

The study was conducted by Yan’an Affiliated Hospital of Kunming Medical University. We used a cluster sampling method to recruit children aged from 3 to 18 years in Yunnan. From October 2010 to March 2015, all the children in the 1309 schools and kindergartens of Yunnan were recruited in this study. The altitude of each school was measured to evaluate the altitude at which those children lived. This study was carried out after permission from the Ethics Committee of Yan’an Affiliated Hospital of Kunming Medical University (Yunnan, China), and informed written consent was obtained from the parents or legal guardians of each child.

Each participant completed a questionnaire, which included information such as birth date, gender, gestational age, birth weight, parent age, and the ethnic group. We used a two-step method to diagnose CHD. First, a primary screen consisting of a physical examination was performed on all participants, and children with signs of cyanosis, cardiac murmur, and splitting of the second heart sound were suspected as patients with CHD. Second, the subjects suspected to have CHD were further screened by echocardiography (Philips, CX50) to assess their parasternal long-axis, short-axis, apical four-chamber, and subcostal views (2D and Doppler) to confirm CHD by an expert in pediatric senior echocardiography. The classification of CHD was based on the International Classification of Diseases, Ninth Revision, and the Clinical Modification code. However, patent foramen ovale (defects <4 mm in diameter) was excluded from the inclusion criteria.

Statistical analyses: Analysis were done with SPSS version 17.0 software package (SPSS, Chicago, Illinois). Chi-square and Fisher’s exact test were used compare rates. For the comparison of the prevalence of CHD in different altitude level regions, a Cochran-Armitage Trend Test was used. Odds ratios and 95% Confidence intervals were calculated. A P value <0.05 was considered statistically significant.

Results

A total of 244,023 children (127, 295 boys) participated in the primary physical examination with a mean (SD) age of 9.8 (2.1) years. Furthermore, 24,646 children [13,122 girls, mean age of 9.2 (2.7) years] suspected to have CHD were further screened by echocardiography.

A total of 1695 children (877 girls) were diagnosed with CHD, giving an estimated prevalence of CHD of 6.9 (95% CI, 1.78-12.11) per 1000 live births in Yunnan. There was a clear sex difference in prevalence of CHD, with 7.5 per 1000 live births among 116,728 girls compared to 6.4 per 1000 live births among 127,295 boys (OR, 1.17; 95% CI, 1.06-1.29; P<0.01) higher prevalence of CHD was found in mothers aged over 35 years (OR, 1.36; 95% CI; 1.23-1.51; P<0.001), children with gestational age <37 weeks (OR, 1.74; 95% CI; 1.52-1.99; P<0.001), and birthweight <2500 g (OR: 2.23, 95% CI; 1.98-2.51; P<0.001) (Table I).There was a significant difference between different altitudes (P<0.001), prevalence of CHD increasing with elevation.

TABLE I Characteristics of 244023 Schoolchildren With Congenital Heart Disease in Yunnan, China
Variable CHD Prevalence
Sex* 
  Boys (n=127295) 818 6.426
  Girls (n=116728) 877 7.513
Maternal age (y)#
  <35 (n=183018) 1165 6.36
  35 (n=61005) 530 8.69
Gestation age (wk)#
  <37 (n=22430) 253 11.3
  37 (n=221593) 1442 6.51
Birthweight (g)#
  <2500 (n=24591) 337 13.7
  2500 (n=219432) 1358 6.19
CHD: Congenital heart disease; Prevalence: per 1000 live births; *P<0.01; #P<0.001.
TABLE II Subtypes of Congenital Heart Disease Among Schoolchildren in Yunnan, China
Type of   Male      Female Total
CHD No. Prevalence No. Prevalence No. Prevalence
ASD 346 (42.2) 2.718 370 3.170 716 2.893
VSD 227 (27.6) 1.783 241 2.065 468 1.918
PDA 135 (16.9) 1.061 151 1.293 286 1.213
BAV 36 (4.1) 0.283 34 0.291 70 0.287
TOF 16 (1.8) 0.126 15 0.129 31 0.127
PS 15 (1.6) 0.118 13 0.111 28 0.115
AVSD 11 (1.5) 0.086 14 0.120 25 0.102
TGA 3 (0.3) 0.024 3 0.026 6 0.025
Ebstein 2 (0.3) 0.016 4 0.034 6 0.025
others 27 (3.5) 0.212 32 0.274 59 0.242
CHD: Congenital heart disease; Prevalence: per 1000 live births; ASD: atrial septal defect, VSD: ventricular septal defect, PDA: patent ductus arteriosus BAV: bicuspid aortic valve, TOF: Tetralogy of Fallot, PS: pulmonary valvular stenosis; AVSD: Atrioventricular septal defect; TGA: Transposition of the great arteries.

Atrial septal defect was the most common acyanotic congenital heart lesions (Table II). Fifteen diverse ethnic groups were enrolled. Compared with the Chinese Han population, many other ethnic groups, including Tibetan, Hani, Yi, Naxi, Lisu, Jingpo, and Achang ethnic groups showed a higher prevalence of confirmed CHD (P<0.05) (Table III).

TABLE III Prevalence of Congenital Heart Diseases by Different Ethnic Groups in Yunnan, China
Ethnic group No. CHD Prevalence
Han 144132 890 6.17
Tibetan* 9443 85 9.00
Bai 37300 263 7.05
Dai 15590 98 6.2
Hani* 5570 54 9.69
Yi* 14383 123 8.55
Zhuang 3564 15 4.2
Lisu* 3219 58 18.0
Wa 2094 20 9.55
Jingpo* 1630 22 13.49
Jino 1172 8 6.83
Miao 851 8 9.40
Hui 1063 7 6.58
Achang* 323 5 15.48
Others 419 2 4.78
CHD: Congenital heart disease; Prevalence: per 1000 live births; *P value<0.05 compared with Chinese Han population.

Discussion

Our study observed that Yunnan has a higher CHD prevalence than other areas of China, and ASD is the most common subtype. The higher prevalence of CHD was found among children who were born in high-altitude regions. The prevalence of CHD in most of the minority ethnic groups was higher than that in Han Chinese. Meanwhile, some other risk factors such as advanced maternal age, low birth weight, and premature birth were associated with CHD.

Our study has some limitations. We did not perform echocardiography in all children; thus, some minor lesions without cardiac murmurs such as very small ASD, tiny PDA, and uncomplicated bicuspid aortic valve might have been missed on physical examination. Furthermore, some children with severe or complex malformations might have died at a younger age, so the prevalence of CHD in our investigation may be underestimated. Secondly, we use the altitude of each school to represent the altitude at which the children were born and lived in, which may not be very accurate. Furthermore, the physical examination, such as auscultation to screen CHD, may differ depending on the doctor even though their medical training may be similar.

Some previous studies in China have shown that the prevalence of CHD to vary from 1.5 to more than 20 per 1000 live birth [4-6]; which might have been due to the varying use of echocardiography as a diagnosis tool. Our data indicated that ASD was the most frequent lesion, which was consistent with some previous reports [7]; though others found VSD to be the most common type [8]. Some altitude correlation studies have indicated that a higher prevalence of CHD is found in high-altitude regions [9,10], which was consistent with our results. Furthermore, decreased oxygen tension has been implicated as an extrinsic factor for the formation of CHD in high-altitude areas [11]. Previous authors have also shown that maternal age ³35 years, preterm birth, and low birth weight are risk factors for CHD [12,13]. Meanwhile, these results were also consistent with some studies conducted in China [14], but the biological mechanism for these risk factors needs further exploration. As a multi-ethnic country, some previous studies have shown that the different ethnic groups in China have different a prevalence of CHD [14,15]. This may be associated with a unique genetic background, consanguineous marriage, or bad living environment.

Through this school-based, multiple-ethnic, and multiple altitude study with an enormous number of participants, we can conclude that a physical examination combined with echocardiography is a reliable, economical, and efficient method to screen CHD in remote areas. We obtained data on risk factors and the prevalence of CHD in Yunnan, which provides additional information on the epidemiology of CHD as well as additional support for the development of diagnostic and treatment plans in many high-altitude and poor minority areas of Yunnan, China.

Contributors: SH: drafting the work and revising it critically; CW: agreement to be accountable for all aspects; ZH: design of the work; YL: acquisition of data; YD: acquisition of data; XG: acquisition of data; DH: analysis of data; ZhN: analysis of data; WC: interpretation of data. LJ: final approval of the version to be published. All authors approved the final version of manuscript, and are accountable for all aspects related to the study.

Funding: The National Natural Science Foundation of China (31160230 and 81560060); Competing interest: None stated.


What This Study Adds?

High-altitude levels, maternal age prematurity and ethnicity were associated with the prevalence of congenital heart disease in Southwest China.


References

1. Ottaviani, G. and L.M. Buja, Update on congenital heart disease and sudden infant/perinatal death: from history to future trends. J Clin Pathol. 2017;70:555-62.

2. Hinton RB. Genetic and environmental factors contributing to cardiovascular malformation: A unified approach to risk. J Am Heart Assoc. 2013;2:e000292.

3. Yu M, Ping Z, Zhang S, He Y, Dong R, Guo X, The survey of birth defects rate based on birth registration system. Chin Med J. 2015;128:7-14.

4. Yu Z, Xi Y, Ding W, Han S, Cao L, Zhu C, et al. Congenital heart disease in a Chinese hospital: Pre- and postnatal detection, incidence, clinical characteristics and outcomes. Pediatr Int. 2011;53:1059-65.

5. Liu X, Liu G, Wang P, Huang Y, Liu E, Li D, et al. Prevalence of congenital heart disease and its related risk indicators among 90,796 Chinese infants aged less than 6 months in Tianjin. Int J Epidemiol. 2015;44: 884-93.

6. Zhao QM, Ma XJ, Jia B, Huang GY. Prevalence of congenital heart disease at live birth: An accurate assessment by echocardiographic screening. Acta Paediatr. 2013;102: 397-402.

7. Bjornard K, Riehle-Colarusso T, Gilboa SM, Correa A. Patterns in the prevalence of congenital heart defects, metropolitan Atlanta, 1978 to 2005. Birth Defects Res A Clin Mol Teratol, 2013;97:87-94.

8. Sadowski SL. Congenital cardiac disease in the newborn infant: past, present, and future. Crit Care Nurs Clin North Am. 2009;21:37-48, vi.

9. Miao CY, Zuberbuhler JS, Zuberbuhler JR. Prevalence of congenital cardiac anomalies at high altitude. J Am Coll Cardiol, 1988;12: 224-8.

10. Chun H, Yue Y, Wang Y, Dawa Z, Zhen P, La Q, et al. High prevalence of congenital heart disease at high altitudes in Tibet. Eur J Prev Cardiol. 2018:. 2047487318812502.

11. Bishop T, Ratcliffe PJ. HIF hydroxylase pathways in cardiovascular physiology and medicine. Circ Res. 2015;117:65-79.

12. Miller A, Riehle-Colarusso T, Siffel C, Frias JL, Correa A, Maternal age and prevalence of isolated congenital heart defects in an urban area of the United States. Am J Med Genet A. 2011;155A:2137-45.

13. Lopes S, Guimaraes ICB, Costa SFO, Acosta AX, Sandes KA, Mendes CMC. Mortality for critical congenital heart diseases and associated risk factors in newborns. A Cohort Study. Arq Bras Cardiol. 2018;111;666-73.

14. Liu F, Yang YN, Xie X, Li XM, Ma X, Fu, ZY, et al. Prevalence of congenital heart disease in xinjiang multi-ethnic region of China. PLoS One. 2015,10: e0133961.

15. Chen QH, Liu FY, Wang XQ, Qi GR, Liu PF, Jin XH, et al. [A cross-sectional study of congenital heart disease among children aged from 4 to 18 years at different altitudes in Qinghai province, China]. Zhonghua Liu Xing Bing Xue Za Zhi. 2009;30:1248-51.

 

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