The Effect of Long Distance Air-travel on Serum Viscosity and Prothrombin Time

BACKGROUND: Economy class syndrome is medically described as deep vein thrombosis, it is worldwide issued that Long-Distance Air-Travel is a risk factor for venous thromboemborism. Some study provides evidence and theoretical explanations for the hypothesis that long-distance is a risk factor for venous thromboembolism. The purpose of this study is to provide the useful prevention of venous thromboembolism for long-distance travelers in comparison to the effect of long distance air-travel on serum viscosity and prothrombin time between flight level and ground level. METHODS: Subjects selected healthy volunteers that had no abnormal findings in evaluation (alpha2-plasmin inhibitor, plasminogen, anti-thrombin III, protein C, protein S) for hypercoagulability. 5subjects (1 male, 4 females) had a seat on economy class of ground training facility designed for flight attendant and their activities limited as possible during about 8 hours at Sep. 16, 2001. Also, 5 subjects had a seat on the economy class of Asiana Airlines (B-777) from Sydney in Australia to Seoul in Korea at Mar. 3, 2002. In the flight, Actual flight altitude was 31,000 feet, cabin altitude was 4,800 feet and cabin temperature was 25degrees C. We have investigated the serum viscosity used by viscometer and prothrombin time. These data were analyzed statistically by General linear model (spsswin ver. 10.0). RESULTS: The results showed that there were no differcence between Flight Group and Ground Group statistically. However, the serum viscosity of flight group by position was some higher than ground group but these defference was not statistically significance (P=0.419). Also, the serum viscosity of flight group by time had a decreased trend but these trend was not statistically significance (P=0.061). The prothrombin time of flight group by position was some lower than ground group but these defference was not statistically significance (P=0.472). Also, the prothrombin time of ground group by time had a decreased trend but these trend was not statistically significance (P=0.217). CONCLUSION: This study shows the prediction to venous thrombosis more closely relates to prothrombin time than serum viscosity under immobilization to healthy people on the ground environment. Exercise is more useful method than hydration to prevent venous thrombosis on the ground environment. In the flight environment, we think that hydration is also useful method to prevent venous thrombosis because of more dry environment inside flying aircraft. But, this study was decreased serum viscosity between samples according to time. I think serum viscosity can be reduced by vibration effect inside flying aircraft. Serum viscosity and prothrombin time between samples according to position were not statistically significant. I think that risk for the healthy people is poorly quantified and possibly overestimated that long-distance air-travel is a risk factor for venous thromboembolism.

Correlation Between Total Cholesterol and Body Mass Index, Waist-Hip Ratio of Flight Attendants

BACKGROUND: Number of people who suffer from obesity tends to increase throughout the world. The obesity may cause various illnesses such as hypertension, diabetes, arteriosclerosis etc. However, obesity can be prevented by diet and weight control. This study is to find the relationship between severity of obesity and amount of blood cholesterol which is closely related to hypertension. There are two ways to indicate the severity of obesity; body mass index and waist hip ratio. Especially, the latter is favored for abdominal obesity. The goal of this study is to find out which method is more closely related to the serum total cholesterol. METHODS: From Oct. 1st 2000 to Sept. 30th 2001, the experiment is based on 585 people who are flight attendants in the A airline company. This study measured body mass index, waist hip ratio and serum total cholesterol against sex, age, height, and weight. We analyzed the data by t-test, analysis of covariance, Pearson correlation, multiple linear regression analysis. As a result, we will study the correlation between serum total cholesterol and age, sex, height, and weight by defining the serum total cholesterol as a dependent variable and any other variables that affect changes in the serum total cholesterol as independent variables. RESULTS: The 585 flight attendants (78 male and 507 female)were statistically analyzed. The average serum total cholesterol (ASTC) was significantly higher for male; ASTC of male was 175.67+/-30.23 and that of female was 166.37+/-25.57 (P=.011). ASTC was peak at the age group of 30s for male (177.97+/-30.54 , P=.0443), but female did not have much difference between the age group of 20s and that of 30s (166.33+/-24.54, 166.34+/-29.26, P=0.880). As a result from analyzing the relationship among the variables. ASTC and waist hip ratio were positively related for both male and female. Moreover, body mass index and waist hip ratio were also positively related for both genders. However, the relationship between ASTC and waist hip ratio for male was more closely related than for female (P=.033). CONCLUSION: Age, body mass index and waist hip ratio are positively related for both genders. Therefore, an appropriate exercise and a diet control for ages are necessary as getting older in order to prevent disease caused by obesity. Besides, serum total cholesterol for male was higher for 30s than 20s. Thus, especially, male within the age group of 30s should be alert to the obesity carefully with performing exercise regularly and diet control by lowering the intake of fat and alcohol.