Infrared thermography was performed on 38 forestry workers. The thermograms were analyzed separately for the left and right hands of each subject. Of 75 hands evaluated, vibration-induced white finger was noted in 18 (VWF group), and no symptoms were noted in 57 (non-VWF group). In addition to the above two groups, 42 subjects (84 hands) who had no symptoms of vibration exposure were used as a control group. Based of the thermograms taken after a local warming of the hands for 5min, the temperature distributions of the dorsal aspect of subject's hands were evaluated, and the thermal images of the hand with VWF were categorized into three main patterns. To establish a quantitative evaluation index that incorporates the characteristic thermal image observed in the VWF group, we constructed the representative parameters for each of the three thermogram patterns, and a linear discriminant analysis was performed using the presence or absence of VWF symptoms as the dependent variable and the constructed parameters as the independent variables. A discriminant score derived from this model expression was used as the evaluation index. The accuracy of the index was estimated according to a receiver operating characteristic (ROC) curve, and the area under the curve of 0.942 was obtained (p<0.001). When the cutoff point was set at the maximum point in the Youden index, the sensitivity of the VWF group was 94.4%, and the specificity of the non-VWF group and control group was 84.2% and 89.3%, respectively. These findings suggest that this newly proposed quantitative analysis method, which uses the thermal distributions of the dorsal side of the hand as indicators, may be useful for evaluating peripheral circulatory impairment of HAVS.

OBJECTIVESThe purposes of this paper were to evaluate the serum leptin levels in healthy adolescents and to establish standard age variation curves.

METHODSNine hundred six (414 boys and 492 girls) healthy adolescents were investigated. The maximum increment age in height (MIA) was identified in 124 boys and 130 girls. The menarcheal age (MA) was obtained for 130 girls. Fasting leptin levels were measured by enzyme immunoassay. The MIA was calculated by proportional allotment of yearly height increments.

RESULTSSerum leptin levels did not change in boys and girls from the ages of 9 to 11. They decreased after the age of 11 in boys, while they increased in girls. Stepwise multiple regression analysis revealed that serum leptin levels were closely related to pubertal stage. The levels decreased remarkably after MIA in boys and increased remarkably after MA in girls. We drew standard age variation curves of serum leptin levels by calculating the 25th, 50th and 75th percentiles for each age in both boys and girls. The percentile curves for boys were divided into pre-MIA and post-MIA curves. Those for girls were divided into pre-MA and post-MA curves.

CONCLUSIONWe have devised a potentially useful method for evaluating serum leptin levels in adolescents considering the effects of gender and growth.