OBJECTIVES: Congenital birth defects are the main source of disease burden among children under 5 years old in China. This study aims to compare the trends in disease burden of different congenital birth defects among Chinese children under 5 years old from 1990 to 2019, and to provide a scientific basis for strengthening the comprehensive prevention and control of birth defects. METHODS: Based on data from the Global Burden Disease (GBD) in 2019, the incidence mortality rate, and disability-adjusted life years (DALYs) rate of congenital birth defects among Chinese children under 5 years old from 1990 to 2019 were selected as evaluation indicators. The Joinpoint regression model was used to analyze the trends in disease burden of different types with congenital birth defects over three decades. The study also compared the differences in disease burden of congenital birth defects among children under 5 years old by gender. RESULTS: Compared to 1990, the DALYs rates of congenital heart anomalies (1 931.91/100 000), digestive congenital anomalies (364.63/100 000), neural tube defects (277.20/100 000), congenital musculoskeletal and limb anomalies (133.33/100 000), and Down syndrome (128.22/100 000) in children under 5 years old in China in 2019 were decreased 70.78%, 71.61%, 86.21%, 36.84% and 73.65%, respectively. From 1990 to 2019, the mortality rates and DALYs rates of different congenital birth defects showed an overall downward trend, but the incidence of digestive congenital anomalies and Down syndrome showed an upward trend after 2005 and 2001, respectively. Except for congenital musculoskeletal and limb anomalies, incidence of the remaining categories of birth defects were higher in boys than that in girls. CONCLUSIONS The disease burden of congenital birth defects in children under 5 years old in China is decreased substantially from 1990 to 2019, but the burden of congenital heart anomalies is still serious and the incidence of some birth defect diseases is on the rise, and it is still crucial to strengthen the prevention and treatment for birth defects in children and propose targeted measures according to their gender characteristics.
Child, Preschool ; Female ; Humans ; Male ; China/epidemiology* ; Cost of Illness ; Down Syndrome/epidemiology* ; East Asian People ; Congenital Abnormalities/epidemiology*

Objective: To explore the current situation of fetal heart defects in Yunnan Province and surrounding high altitude areas and the social factors affecting pregnancy outcome. Methods: This is a retrospective study. Pregnant woman who underwent fetal echocardiography and diagnosed as fetal cardiac defects in Yunnan Fuwai Cardiovascular Hospital from June 2017 to January 2021 were included. According to the clinical prognostic risk scoring system and grading criteria of fetal cardiac birth defects, the cases were divided into grade Ⅰ to Ⅳ. The disease distribution and proportion of each prognostic grade, pregnancy outcomes were analyzed and compared. The cases were divided into continued pregnancy group and terminated pregnancy group according to pregnancy outcome. The social factors that may affect the selection of pregnancy outcomes were analyzed by multivariate logistic regression analysis. Results: A total of 4 929 fetal echocardiography examination data were collected, and 4 464 cases (90.57%) were from Yunnan Province and surrounding high altitude areas. 2 166 cases of heart defects were finally analyzed, including 998 cases of congenital heart disease (CHD), 93 cases of cardiac tumors, cardiomyopathy and arrhythmia, 1 075 cases of foramen ovale, ductus arteriosus abnormalities and normal variations. The pregnant women were (29.2±5.0) years old with (25.6±3.8) gestational weeks. The number of cases with prognostic grade from Ⅰ to Ⅳ was 1 037 (47.88%), 620 (28.62%), 314 (14.50%), and 44 (2.03%), respectively. And 151 cases (6.97%) were not classified. The cases of normal variation and thin aortic arch development accounted for 42.66% (924/2 166), 5.22% (113/2 166), respectively. The top 3 diseases of grade Ⅱ were ventricular septal defect, coarctation of aorta and mild-moderate pulmonary stenosis, respectively, and their distribution was 11.63% (252/2 166), 3.92% (85/2 166) and 2.35% (51/2 166) respectively in all cases of heart defects, and 25.25% (252/998), 8.52% (85/998) and 5.11% (51/998) respectively in cases of CHD. Among the cases rated as grade Ⅲ and Ⅳ, most of them were complicated congenital heart disease, and the disease types are scattered. The more common cases in grade Ⅲ were complete transposition of great arteries (accounting for 2.40% (52/2 166) of all cases with heart defects, 5.21% (52/998) of all cases with CHD) and pulmonary artery occlusion (type Ⅰ to Ⅲ) with ventricular septal defect (accounting for 2.17% (47/2 166) of all cases with heart defects, and 4.71% (47/998) of all cases with CHD). In grade Ⅳ, single ventricle (0.74% (16/2 166) of all cases with heart defects, 1.60% (16/998) of all cases with CHD) and left ventricular dysplasia syndrome (0.65% (14/2 166) of all cases with heart defects, 1.40% (14/998) of all cases with CHD) are more common. A total of 1 084 cases were successfully followed up, and 675 cases were born, 392 cases were terminated, spontaneous abortion occurred in 17 cases. The proportion of terminated pregnancy cases was significantly increased from grade Ⅰ to Ⅳ, accounting for 5.24% (21/401), 27.78% (70/252), 89.54% (214/239) and 95.56% (43/45), respectively. Among the terminated pregnancy cases, those with grade Ⅲ accounted for the highest proportion (54.59% (214/392)). The distribution of terminated pregnancy cases was mainly complex congenital malformations or diseases with very poor prognosis (pregnancy outcome grade Ⅲ and Ⅳ), and proportion of terminated pregnancy with pregnancy outcome grade Ⅰ and Ⅱ cases (normal variation or good prognosis) accounted for 5.36% (21/392) and 17.86% (70/392), respectively. The results of multivariate logistic regression analysis showed that pregnant women with low education (high school and below: OR=2.73, 95%CI 1.26-5.93, P<0.001; illiteracy: OR=3.27, 95%CI 1.29-7.10, P<0.001) and low family income (Annual income<100 000 yuan: OR=2.47, 95%CI 1.69-5.12, P<0.001) were more likely to choose termination of pregnancy in case of fetal heart defect. Conclusion: In Yunnan province and the surrounding high altitude areas, the disease distribution of fetal heart defect is mainly simple or low-risk disease, but the complex malformation, especially the disease with poor pregnancy outcome, accounts for a relative high proportion. Pregnancy termination also occurs in some cases with good pregnancy outcome. The education level and family income of pregnant women may affect their choice of pregnancy outcome in case of fetal heart defect.
Pregnancy ; Female ; Humans ; Young Adult ; Adult ; Retrospective Studies ; Altitude ; China/epidemiology* ; Heart Defects, Congenital/diagnostic imaging* ; Heart Septal Defects, Ventricular ; Echocardiography ; Fetal Heart/diagnostic imaging*

BACKGROUND: Congenital heart disease (CHD) is one of the most common congenital malformations in humans. Inconsistent results emerged in the existed studies on associations between air pollution and congenital heart disease. The purpose of this study was to evaluate the association of gestational exposure to air pollutants with congenital heart disease, and to explore the critical exposure windows for congenital heart disease. METHODS: The nested case-control study collected birth records and the following health data in Tianjin Women and Children's Health Center, China. All of the cases of congenital heart disease from 2013 to 2015 were selected matching five healthy controls for each case. Inverse distance weighting was used to estimate individual exposure based on daily air pollution data. Furthermore, the conditional logistic regression with distributed lag non-linear model was performed to identify the association between gestational exposure to air pollution and congenital heart disease. RESULTS: A total of 8,748 mother-infant pairs were entered into the analysis, of which 1,458 infants suffered from congenital heart disease. For each 10 µg/m³ increase of gestational exposure to PM_2.5, the ORs (95% confidence interval, 95%CI) ranged from 1.008 (1.001-1.016) to 1.013 (1.001-1.024) during the 1^st-2^nd gestation weeks. Similar weak but increased risks of congenital heart disease were associated with O₃ exposure during the 1^st week and SO₂ exposure during 6^th-7^th weeks in the first trimester, while no significant findings for other air pollutants. CONCLUSIONS This study highlighted that gestational exposure to PM_2.5, O₃, and SO₂ had lag effects on congenital heart disease. Our results support potential benefits for pregnancy women to the mitigation of air pollution exposure in the early stage, especially when a critical exposure time window of air pollutants may precede heart development.
Infant ; Pregnancy ; Child ; Humans ; Female ; Air Pollutants/analysis* ; Case-Control Studies ; Prenatal Exposure Delayed Effects/epidemiology* ; Heart Defects, Congenital/etiology* ; China/epidemiology* ; Particulate Matter/adverse effects* ; Maternal Exposure/adverse effects*

BACKGROUND: Few prospective studies have investigated the association between paternal occupational exposures and risk of infant congenital heart defects (CHDs). We investigated the associations between paternal occupational exposures, frequency of use, and concurrent or sequential exposure to a mixture of compounds and the risk of infant CHDs. METHODS: Our study examined 28,866 participants in the Japan Environment and Children's Study. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) associated with paternal occupational exposures during the 3 months until pregnancy was noticed after adjustment for potential confounding factors of the infant CHDs. CHD diagnosis was ascertained from medical record. RESULTS: In total, 175 were diagnosed with infant CHDs. The number of fathers who were exposed to the following substances at least once a month were: 11,533 for photo copying machine/laser printer, 10,326 for permanent marker, 8,226 for soluble paint/inkjet printer, 6,188 for kerosene/petroleum/benzene/gasoline, 4,173 for organic solvents, 3,433 for chlorine bleach/germicide, 2,962 for engine oil, 2,931 for insecticide, 2,460 for medical sterilizing disinfectant, 1,786 for welding fumes, 1,614 for dyestuffs, 1,247 for any products containing lead-like solder, 986 for herbicide, 919 for radiation/radioactive substances/isotopes, 837 for lead-free solder, 341 for microbes, 319 for formalin/formaldehyde, 301 for agricultural chemical not listed above or unidentified, 196 for general anesthetic for surgery at hospital, 171 for anti-cancer drug, 147 for chromium/arsenic/cadmium, 88 for mercury and 833 for other chemical substances. Paternal occupational exposure regularly to photo copying machine or laser printer and soluble paint/inkjet printer were associated with higher risks of infant CHDs: the adjusted ORs (95%CIs) were 1.38 (1.00-1.91) and 1.60 (1.08-2.37), respectively. The higher risks were also observed for occasional exposure to engine oil, any products containing lead-like solder lead-free solder, and microbes; the adjusted ORs (95%CIs) were 1.68 (1.02-2.77), 2.03 (1.06-3.88), 3.45 (1.85-6.43), and 4.51, (1.63-12.49), respectively. CONCLUSIONS Periconceptional paternal occupational exposure was associated with a higher risk of infant CHDs. Further studies using biomarkers of the association between paternal occupational exposure and infant CHDs are warranted.
Male ; Humans ; Infant ; Child ; Japan/epidemiology* ; Prospective Studies ; Risk Factors ; Case-Control Studies ; Occupational Exposure/adverse effects* ; Heart Defects, Congenital/epidemiology* ; Fathers

Objective: To analyze the classification, diagnosis and treatment status of patients with pulmonary hypertension (PH) in Yunnan province. Methods: This was a retrospective study. Hospitalized patients with PH at Yan'an Affiliated Hospital of Kunming Medical University from January 2012 to December 2019 were enrolled. The clinical data of enrolled patients, including demographic data, comorbidities, targeted drug therapy, echocardiography and right heart catheterization results, were obtained through the electronic medical record system. The composition ratio of PH, diagnosis and treatment were analyzed. Results: A total of 13 590 patients with PH were enrolled, accounting for 3.09% (13 590/440 056) of the total number of hospitalizations during the same period. The composition of PH was predominantly pulmonary arterial hypertension (PAH) (55.50% (7 542/13 590)), followed by pulmonary hypertension (PH) caused by left heart disease (24.16% (3 284/13 590)). Among them, PAH could be subdivided into four types: idiopathic pulmonary arterial hypertension (IPAH), PAH associated with connective tissue disease, PAH associated with portal hypertension, and PAH associated with congenital heart disease (CHD-PAH), with CHD-PAH as the predominating type (98.09% (7 398/7 542). Patients with PAH were predominantly adolescents. In hospitalized patients with PH, from 2012 to 2019, the proportion of children and adolescents showed a decreasing trend from year to year, and the proportion of middle-aged and older adults showed a significant increasing trend, and the proportion of female patients showed a gradual decreasing trend, and the proportion of patients with comorbid hypertension, diabetes mellitus, coronary artery disease, arrhythmia, and pneumonia showed an increasing trend. A total of 1 034 patients (7.61% (1 034/13 590)) underwent right heart catheterization. The concordance rate between echocardiographic and right heart catheterization findings was (86.98% (875/1 006)). A total of 2 574 (18.94%) of PH patients were treated with PAH targeted drugs, of which 58.16% (1 497/2 574) were treated with monotherapy. Among the PH patients treated with PAH targeted drugs, the majority of patients were PAH patients (86.44% (2 225/2 574)), and 83.53% (2 150/2 574) patients treated with PAH targeted drugs were CHD-PAH. Conclusions: Hospitalized PH patients in our center between 2012 and 2019 are predominantly CHD-PAH, and the proportion of patients receiving right heart catheterization and targeted drug therapy is relatively low. The percentage of middle-aged and elderly PH patients shows an increasing trend from year to year, as well as the percentage of those with concomitant comorbidities.
Child ; Aged ; Adolescent ; Middle Aged ; Humans ; Female ; Hypertension, Pulmonary/therapy* ; Retrospective Studies ; China/epidemiology* ; Familial Primary Pulmonary Hypertension ; Pulmonary Arterial Hypertension/complications* ; Heart Defects, Congenital

Objective: To analyze the classification, diagnosis and treatment status of patients with pulmonary hypertension (PH) in Yunnan province. Methods: This was a retrospective study. Hospitalized patients with PH at Yan'an Affiliated Hospital of Kunming Medical University from January 2012 to December 2019 were enrolled. The clinical data of enrolled patients, including demographic data, comorbidities, targeted drug therapy, echocardiography and right heart catheterization results, were obtained through the electronic medical record system. The composition ratio of PH, diagnosis and treatment were analyzed. Results: A total of 13 590 patients with PH were enrolled, accounting for 3.09% (13 590/440 056) of the total number of hospitalizations during the same period. The composition of PH was predominantly pulmonary arterial hypertension (PAH) (55.50% (7 542/13 590)), followed by pulmonary hypertension (PH) caused by left heart disease (24.16% (3 284/13 590)). Among them, PAH could be subdivided into four types: idiopathic pulmonary arterial hypertension (IPAH), PAH associated with connective tissue disease, PAH associated with portal hypertension, and PAH associated with congenital heart disease (CHD-PAH), with CHD-PAH as the predominating type (98.09% (7 398/7 542). Patients with PAH were predominantly adolescents. In hospitalized patients with PH, from 2012 to 2019, the proportion of children and adolescents showed a decreasing trend from year to year, and the proportion of middle-aged and older adults showed a significant increasing trend, and the proportion of female patients showed a gradual decreasing trend, and the proportion of patients with comorbid hypertension, diabetes mellitus, coronary artery disease, arrhythmia, and pneumonia showed an increasing trend. A total of 1 034 patients (7.61% (1 034/13 590)) underwent right heart catheterization. The concordance rate between echocardiographic and right heart catheterization findings was (86.98% (875/1 006)). A total of 2 574 (18.94%) of PH patients were treated with PAH targeted drugs, of which 58.16% (1 497/2 574) were treated with monotherapy. Among the PH patients treated with PAH targeted drugs, the majority of patients were PAH patients (86.44% (2 225/2 574)), and 83.53% (2 150/2 574) patients treated with PAH targeted drugs were CHD-PAH. Conclusions: Hospitalized PH patients in our center between 2012 and 2019 are predominantly CHD-PAH, and the proportion of patients receiving right heart catheterization and targeted drug therapy is relatively low. The percentage of middle-aged and elderly PH patients shows an increasing trend from year to year, as well as the percentage of those with concomitant comorbidities.
Child ; Aged ; Adolescent ; Middle Aged ; Humans ; Female ; Hypertension, Pulmonary/therapy* ; Retrospective Studies ; China/epidemiology* ; Familial Primary Pulmonary Hypertension ; Pulmonary Arterial Hypertension/complications* ; Heart Defects, Congenital

Objective: To explore the prevalence and change trend of severe multiple disabling birth defects in Chongqing City from 2007 to 2020, and to provide a basis for comprehensive prevention and control measures of severe multiple disabling birth defects. Methods: Based on hospital monitoring data, 1 103 children with severe multiple disabling birth defects monitored by all birth defects monitoring institutions in Chongqing City from January 2007 to December 2020 were included in the study. They were grouped by year, perinatal gender, maternal permanent residence (urban/rural), maternal age, different regions and other categories. Chi-square test was used to analyze the differences in the incidence of severe multiple disabling birth defects in different categories, and linear trend test was used to analyze the change trend. Results: From 2007 to 2020, a total of 1 022 314 perinatal births and 1 103 severe multiple disabling birth defects were monitored in Chongqing City, with an incidence of 10.79/10 000, including 11.47/10 000 in urban areas and 9.48/10 000 in rural areas, with an incidence higher in urban areas than in rural areas(χ²=8.424,P=0.004). Male was 10.47/10 000, female was 10.97/10 000, there was no significant difference between male and female(χ²=0.606,P=0.436). The incidence of maternal in different age groups was u-shaped, and there was statistical difference in incidence among different age groups (χ²=59.465, P<0.001). The incidence of maternal in<20 years old and ≥35 years old was higher, and in 25-29 years old was lower. The incidence rate was 17.96/10 000 in 2007 and 7.18/10 000 in 2020, which decreased by 60.02% in 2007-2020. The incidence of neural tube defect, chromosome syndrome, limb shortening and abdominal wall defect decreased by 78.12%, 77.38%, 80.55% and 91.30%, respectively. Severe Congenital heart disease rose by 456.16%. From 2007 to 2020, the overall incidence of the disease showed a decreasing trend (χ²_trend =117.046, P<0.001), except for the rise of severe congenital heart disease, (χ²_trend=8.744, P=0.003), the other four types of diseases were on the decline (neural tube defects χ²_trend =48.618, P<0.001; chromosome syndrome χ²_trend=50.999, P<0.001; limb shortening χ²_trend=73.464, P<0.001; abdominal wall defect χ²_trend=79.863, P<0.001). Conclusion: From 2007 to 2020, the incidence of severe disabling birth defects in Chongqing City showed a downward trend, and there were regional and age differences. The incidence of severe congenital heart disease is on the rise.
Adult ; Child ; China/epidemiology* ; Female ; Heart Defects, Congenital ; Humans ; Incidence ; Male ; Maternal Age ; Pregnancy ; Prevalence ; Rural Population ; Young Adult

OBJECTIVES: To provide reference basis for reducing the mortality for children under 5 years old and promote the healthy development, the mortality for children under 5 years old and the main causes for death in Liuyang City from 2013 to 2020 are analyzed. METHODS: The data of 725 cases of death for children under 5 years old in Liuyang City from 2013 to 2020 were collected.The causes and difference of death among the children were analyzed retrospectively by descriptive statistic methods. RESULTS: There were a total of 144 516 live births in Liuyang City from 2013 to 2020. The mortality for children under 5 years old was 5.01‰, for infants was 3.39‰, and for newborns was 1.63‰. The male child mortality was 5.28‰, and the female child mortality rate was 4.72‰, with significant difference (P>0.05). The mortality for children under 5 years old was seasonal fluctuation, without significant difference among seasons (P>0.05). For the past 5 years, the top 3 causes for death among children under 5 years old were preterm birth and low birth weight, congenital heart disease, and pneumonia. Before death, 341 cases (47.04%) were treated in provincial hospitals, 198 cases (27.31%) in county-level hospitals, 56 cases (7.72%) in village-level hospitals, and 130 cases (17.93%) were not treated. CONCLUSIONS The mortality for children under 5 years old in Liuyang City is gradually reduced in the past 5 years. The main causes for death are premature birth and low birth weight, congenital heart disease and pneumonia. We should develop healthy education, improve the rate of prenatal diagnosis, promote the construction of obstetrics and paediatrics, and fundamentally reduce the mortality for children under 5 years old.
Cause of Death ; Child ; Child Mortality ; Child, Preschool ; Female ; Heart Defects, Congenital ; Humans ; Infant ; Infant Mortality ; Infant, Newborn ; Male ; Pneumonia/epidemiology* ; Pregnancy ; Premature Birth ; Retrospective Studies

Objective: To analyze the current status of clinical treatment and factors influencing postoperative mortality in infants with critical congenital heart disease (CCHD) in China, optimize the perioperative management of CCHD, and provide a new scientific basis for clinical decision-making for the optimal management of these patients. Methods: This is a retrospective single-center study. Infants diagnosed with CCHD in Guangdong Provincial People's Hospital from January 2017 to December 2019 (aged 0-1 years at admission) were enrolled. General clinical information, inpatient treatment information, prognosis and complications were collected and analyzed. Multivariate logistic regression analysis was used to explore the independent risk factors of postoperative death in infants with CCHD. Results: A total of 826 infants with CCHD were included, including 556 males (67.3%) and the age at first admission was 51.0 (5.0,178.3) days. 264 (32.0%) cases were tetralogy of Fallot and 137 (16.6%) cases were total anomalous pulmonary venous return. 195 cases (23.6%) were diagnosed prenatally. 196 cases (23.7%) were treated with prostaglandin. The preoperative invasive ventilation time was 0 (0, 0) hour, and the postoperative invasive ventilation time was 95.0 (26.0, 151.8) hours. A total of 668 cases (80.9%) underwent surgical treatment. The age was 100.5 (20.0, 218.0) days during operation and the operation time was 190.0 (155.0, 240.0) hours. Sixty-two cases (7.5%) received medical treatment, and 96 cases (11.6%) gave up treatment. A total of 675 cases (81.7%) were discharged with improvement, 96 cases (11.6%) were discharged after giving up treatment, 55 cases (6.7%) died and 109 cases (13.2%) were readmitted within one year. Complications occurred in 565 (68.6%) cases, including pneumonia in 334 cases (40.4%) and cardiac arrhythmias in 182 cases (22.0%). Multifactorial analysis showed that delayed chest closure (OR=49.775, 95%CI 3.291-752.922, P=0.005), prolonged post-operative invasive ventilator ventilation (OR=1.003, 95%CI 1.000-1.005, P=0.038) and cardiac hypoplasia syndrome (OR=272.658, 95%CI 37.861-1 963.589, P<0.001) were the independent risk factors for mortality in CCHD infants post-operation. Conclusions: Tetralogy of Fallot and total anomalous pulmonary venous return account for the majority of infants with CCHD. The proportion of infants diagnosed prenatally was less than 1/4. The majority CCHD infants received surgical treatment. The main complications are pneumonia and arrhythmia. Delayed chest closure, prolonged postoperative invasive ventilator ventilation and low cardiac output syndrome are the independent risk factors for postoperative death in infants with CCHD.
China/epidemiology* ; Heart Defects, Congenital/therapy* ; Hospitalization ; Humans ; Infant ; Male ; Prognosis ; Retrospective Studies ; Risk Factors

BACKGROUND: Although congenital hypothyroidism (CH) has been widely studied in Western countries, CH incidence at different administrative levels in China during the past decade remains unknown. This study aimed to update the incidence and revealed the spatial pattern of CH incidence in the mainland of China, which could be helpful in the planning and implementation of preventative measures. METHODS: The data used in our study were derived from 245 newborns screening centers that cover 30 provinces of the Chinese Newborn Screening Information System. Spatial auto-correlation was analyzed by Global Moran I and Getis-Ord Gi statistics at the provincial level. Kriging interpolation methods were applied to estimate a further detailed spatial distribution of CH incidence at city level throughout the mainland of China, and Kulldorff space scanning statistical methods were used to identify the spatial clusters of CH cases at the city level. RESULTS: A total of 91,921,334 neonates were screened from 2013 to 2018 and 42,861 cases of primary CH were identified, yielding an incidence of 4.66 per 10,000 newborns screened (95% confidence interval [CI]: 4.62-4.71). Neonates in central (risk ratio [RR] = 0.84, 95% CI: 0.82-0.85) and western districts (RR = 0.71, 95% CI: 0.69-0.73) had lower probability of CH cases compared with the eastern region. The CH incidence indicated a moderate positive global spatial autocorrelation (Global Moran I value = 0.394, P  < 0.05), and the CH cases were significantly clustered in spatial distribution. A most likely city-cluster (log-likelihood ratio [LLR] = 588.82, RR = 2.36, P  < 0.01) and 25 secondary city-clusters of high incidence were scanned. The incidence of each province and each city in the mainland of China was estimated by kriging interpolation, revealing the most affected province and city to be Zhejiang Province and Hangzhou city, respectively. CONCLUSION This study offers an insight into the space clustering of CH incidence at provincial and city scales. Future work on environmental factors need to focus on the effects of CH occurrence.
China/epidemiology* ; Cluster Analysis ; Congenital Hypothyroidism/epidemiology* ; Humans ; Incidence ; Infant, Newborn ; Retrospective Studies ; Spatial Analysis