Morphologic classification of nailfold capillary microscopy in workers exposed to hand-arm vibration

The aim of this study was to investigate the association between the morphologic classification of nailfold capillary microscopy and the clinical and demographic findings in workers exposed to hand-arm vibration. The subjects were 44 male forestry workers (average age; 51.9 ± 14.8 yr). The nailfold capillaries (NC) and the mean blood flow velocity were measured on the middle finger of the dominant side by a peripheral capillary observer. The analyses were made using 39 subjects after excluding five subjects who received medication for hypertension. The observed NC were classified into 5 types according to Kusumoto's classification: Type I, n=5; Type II, n=15; Type III, n=8; Type IV, n=5; and Type V, n=6. After excluding the subjects in the Type V, we divided the subjects into two groups: Type I/II group, n=20; and Type III/IV group, n=13. In the Type III/IV group, the operating year of handheld vibrating tools was relatively longer, the mean blood flow velocity was significantly slower, and the body mass index was relatively higher as compared to the Type I/II group. These results suggested that the nailfold capillary microscopy may reflect the effect of the vibration exposure.