Subclinical atherosclerosis in northern and southern China: the Chinese paradox.
BACKGROUND
The incidence of coronary heart disease (CHD) is higher in Northern than that in Southern China, however differences in traditional CHD risk factors do not fully explain this. No study has examined the differences in subclinical atherosclerosis that may help explain the differences in incidence. This study examined these differences in subclinical atherosclerosis using coronary computed tomography (CT) for calcification between the Northern and Southern China.


METHODS
We selected a random sample of participants in a large multi-center ongoing epidemiologic study for coronary calcium scanning in one northern city (North) (Beijing, n = 49) and in two southern cities (South) (Shanghai, n = 50, and Guangzhou, n = 50). Participants from the three field centers (mean age 67 years) underwent coronary risk factor evaluation and cardiac CT scanning for coronary calcium measurement using the Multi-Ethnic Study of Atherosclerosis scanning protocol.


RESULTS
Adjusted log-transformed coronary artery calcium score in North China (Beijing) was 3.1 ± 0.4 and in South China (Shanghai and Guangzhou) was 2.2 ± 0.3 (P = 0.04). Mean calcium score for the northern city of Beijing was three times higher than that of the southern city of Guangzhou (P = 0.01) and 2.5 times higher than for the southern city of Shanghai (P = 0.03).


CONCLUSIONS
The extent of subclinical atherosclerosis is significantly higher in the northern city of Beijing than that in the two southern cities of Guangzhou and Shanghai, even after adjusting for standard cardiac risk factors. This finding suggests that standard risk factors do not fully explain north south differences in clinical CHD incidence.
Clinical Research Institute and Key Lab of Health Technology Assessment of Ministry of Health, School of Public Health, Fudan University, Shanghai 200032, China.
Jie
J
Huang
Yang-Feng
YF
Wu
Xiao-Qing
XQ
Liu
Ding
D
Ding
Lian-Cheng
LC
Zhao
Bin
B
Lu
Xian
X
Li
Nathan D
ND
Wong
Laurie D
LD
Dustin
Stanley P
SP
Azen
Robert C
RC
Detrano