CHINESE ADULTS ARE LESS SUSCEPTIBLE THAN WHITE TO DIABETES MELLITUS-RELATED ENDOTHELIAL DYSFUNCTION
Kam S Woo1, Ping Chook1, Wing Y So1, Robyn J McCredie2, Clive S Cockram1, David S Celermajer2.
The Chinese University of Hong Kong, Hong Kong SAR1 and The Royal Prince Alfred Hospital, Sydney, New South Wales2.
Background: Insulin-dependent diabetes mellitus (IDDM) is associated with arterial endothelial dysfunction (ED) in young White adults, a key early event in atherosclerosis. Atherosclerosis is less prevalent in Chinese than in westernised Whites.
Methods: To evaluate whether IDDM in Chinese adults are equally susceptible to ED development, we studied 18 young Chinese IDDM (17-40 years; 11 males) and 18 normal controls in Hong Kong, versus 18 IDDM and normal White controls in Sydney. Brachial artery diameter was measured by high resolution B-mode ultrasound at rest, after flow increase, causing endothelium-dependent dilation (EDD) and after sublingual nitroglycerine (NTG, an endothelium-dependent dilator).
Results: The 4 groups were matched for age, gender, duration of known IDDM, blood pressures, body mass index, diabetic control, vessel diameter, blood urea and cholesterol (TC). EDD (mean±SD% of diameter changes) was similar in the 2 controls, markedly impaired in White IDDM (59.5% of White control, p=0.0001) but mildly impaired in Chinese IDDM (71.4% of Chinese control, p=0.001):
Chinese White
|
Control |
IDDM |
Control |
IDDM |
p-value* |
|
|
Age (yrs) |
29.5±5.1 |
28.0±7.3 |
29.0±7.0 |
29.3±7.1 |
NS |
|
TC (mmol/L) |
4.6±0.8 |
5.0±1.2 |
4.8±1.0 |
5.5±1.1 |
NS |
|
EDD (%) |
9.1±2.0 |
6.5±2.3 |
7.9±2.2 |
4.7±2.0 |
0.001 |
|
NTG (%) |
18.3±5.0 |
13.9±3.4 |
19.4±7.3 |
13.0±4.4 |
NS |
NS: Not significant; * compare Chinese vs White
Conclusion: Chinese appear less susceptible to IDDM-related endothelial dysfunction. This supports environment-gene interaction hypothesis providing relative protection.
