ABNORMAL PERIPHERAL MICROCIRCULATION IN SEEMINGLY NORMAL SUBJECTS LIVING IN BLACKFOOT-DISEASE-HYPERENDEMIC VILLAGES IN TAIWAN

Blackfoot disease (BFD) is an endemic peripheral arterial disease conf ined to the southwestern coast of Taiwan. The cause of the disease has been ascribed to the high-arsenic artesian well water. The purpose of this study was to examine the possible association between the long-t erm exposure to artesian well water and the change in microvascular ci rculation in the absence of peripheral arterial insufficiency. A total of 45 men living in the BFD-hyperendemic villages and another 51 age- sex- body-mass index-matched men who lived in nonendemic villages nea rby were recruited into this study. All subjects were free from periph eral vascular disease (resting ankle-brachial index > 1.00), clinical claudication, cigarette smoking, diabetes mellitus, hypertension, isch emic heart disease, cerebral infarction and obesity. Laser Doppler flo wmetry was used to measure the peripheral microcirculation on the big toes both at 36 degrees C (basal perfusion, P-b) and after a hyperther mic test at 42 degrees C (P-h). The time required to reach P-h (T), an d the average rate (R) of increase from P-b to P-h measured by (P-h-P- b)/T were also calculated. Results showed that those living in the BFD -hyperendemic area had a lower P-b [32.8 +/- 6.0 perfusion units (PU) vs. 67.0 +/- 4.3 PU, p < 0.001], a lower Ph (193.2 +/- 13.6 vs. 231.1. +/- 6.3 PU, p < 0.005), a longer P-h (3.04 +/- 0.19 vs. 1.31 +/- 0.08 min, p < 0.001) and a slower rate of increase from P-b to P-h (48.0 /- 4.8 vs. 76.2 +/- 5.4 PU/min, p < 0.001). The results remained simil ar after excluding 13 subjects with minor arterial insufficiency defin ed as a postexercise ankle-brachial index < 0.90. We conclude that def icits in cutaneous microcirculation of the toes were demonstrated amon g seemingly normal subjects living in the BFD endemic area.