The Study on Active and Environmental Tobacco Smoke in Biological Samples among High School Students in Korea / 한국역학회지

PURPOSE: The objective of this study was to determine the active and environmental tobacco smoke (ETS) in biological samples (plasma, saliva and urine) among high school students in Korea. METHODS: Study samples were from 99 nonsmoker or smoking volunteers from high school in Kyungki-do in 2000. ETS was defined as the having smokers of their family members or their friends. Urinary samples were extracted with ethyl ether at pH 10.5, and the extract was injected in GC-NPD. Plasma or saliva was extracted with methylene chloride at pH 10.5 and the quantification was performed with GC-MS (SIM). Peak shapes and quantitation of nicotine and cotinine were excellent, with linear calibration curves over a wide range of 1 to 3000 ng/mL. RESULTS: The results are as followings1. The prevalence of smoking among study subjects were 18.2% among males and 6.1% among females. A 69.7% of total subjects among both males and females were exposed at ETS. 2. The primary metabolite cotinine of nicotine was good indicator of ETS exposure in nonsmokers. Salivary cotinine was found to be highly correlated to the concentration of cotinine in plasma (r=0.9480). 3. Urine cotinine was increased among those with smokers in their family members, while salivary or blood cotinine was increased among with smoking friends. 4. Blood cotinine was highly correlated with salivary cotinine, but it was relatively poorly correlated with urine cotinine. CONCLUSIONS: In conclusion, the results show how the students in high school in Korea suffer from secondhand smoke. It appeared that salivary cotinine was easy to collect and best way to predict the ETS among adolescents

Familial Correlation and Heritability for Cardiovascular Risk Factors

The goal of this study was to describe the overall genetic contribution of phenotypic variation to cardiovascular disease. The study population included 7,589 family members of 1,891 families, derived from Korean Medical Insurance Corporation. The risk factors considered were systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), and high serum cholesterol. The levels of cardiovascular disease risk factors were adjusted for age, gender, smoking and alcohol drinking. Heritability was estimated from the slope of the line linear regression of offspring on mid-parent. All risk factors showed positive familial correlations, and correlations were generally lower for spouses than for parent- offspring pairs. Spouse correlations showed increasing patterns with age. Parents-offspring correlations showed little variation with age, suggesting that the observed correlations with CVD risk factors were primarily due to genetic influences rather than environmental effects. Estimated heritabilities were 26% for BMI, 26% for high serum cholesterol, 19% for SBP, and 9% for DBP. These results highlight the importance of considering genetic factors in studies of cardiovascular risk factors.