Objective: The epidemiological characteristics of congenital heart disease (CHD) among Tibetan children whose age ranged from 4 to 18 at different altitude were investigated in Qinghai province.
Methods: 32 578 Tibetan children living at 2535 m, 3600 m and 4200 m were surveyed with the following 3 steps: prescreened, counterchecked and diagnosed with color Doppler. The entity distribution was then analysed and the age and gender were compared respectively.
Results: 235 CHD cases were identified. The total morbidity was 7.21 per thousand. CHD morbidity was rising with the increase of altitude with 5.45 per thousand at 2535 m, 6.80 per thousand at 3600 m and 9.79 per thousand at 4200 m respectively. There were significant static differences between 4200 m and the others with chi2 = 7.002 (P < 0.01) to 2535 m and chi2 = 5.540 (P < 0.05) to 3600 m. However, there was no statistical difference between 2535 m altitude and 3600 m altitude. The morbidity in different age had no statistical difference at 2535 m altitude but statistically increased with the increase of age at 3600 m and 4200 m. The total ratio of 16-18 age was significantly higher than other age periods with chi2 = 10.79 (P < 0.005) to 4-7 age period and with chi2 = 5.60 (P < 0.05) to 8-12 age period. The atrial septal defect (ASD) morbidity rates in three places was 39.1% followed by ventricular septal defect (VSD) with 32.8% and patent ductus arteriosus (PDA) with 24.7%. However, the constitute of CHD was different in different altitudes that VSD with 43.5% at 2535 m, ASD with 42.8% at 3600 m and PDA with 50.8% at 4200 m which was the highest morbidity.
Conclusion: Morbidity, constitutes and difference in gender and age were related to altitude.