γ-Glutamyltransferase and cancer risk: The Korean cancer prevention study.

Elevated serum γ-glutamyltransferase (GGT) is a marker of hepatic injury and is associated with risk of chronic disease. However, the value of GGT as a biomarker for cancer risk remains unclear. Therefore, we evaluated the association of serum GGT with cancer incidence among more than 1.6 million Koreans. We included 1,662,087 Koreans (1,108,121 men and 553,966 women aged 20-95 years) who received health insurance from the National Health Insurance Service and had a biennial medical evaluation between 1995 and 1998. Follow-up was through December 2012. Using Cox proportional hazards models, we adjusted for age, smoking status, alcohol consumption, exercise and body mass index after exclusion of early cases (cancer diagnosis or death within 5 years of starting follow-up) and estimated hazard ratios (HRs) of overall and organ-specific cancer incidence by GGT quintiles. During the 17-year follow-up, 129,087 new cancer cases occurred among the participants. Across levels of GGT, there was a positive gradient of HR and the highest quintile of GGT (≥ 60 IU/L) had the highest HR for all cancers in both men and women. By cancer site, the association was strongest for liver cancer, comparing the highest and lowest strata in men [HR, 6.67; 95% confidence interval (95%CI), 5.88-7.57] and in women (HR, 7.57; 95%CI, 6.41-8.94). Significant associations were also observed for cancers of the esophagus, larynx, stomach, colorectal, bile duct and lung in men and of the bile duct in women. Increased serum GGT level is independently associated with risk of cancer.

Effect of prolonged breast-feeding on risk of atopic dermatitis in early childhood.

The effect of breast-feeding on the risk of developing atopic disease remains controversial. This study is an investigation of the effect of breast-feeding on current atopic dermatitis (AD) among Korean children. This cross-sectional study of children's histories of current AD and environmental factors was completed by the subjects' parents. The subjects included 10,383 children aged 0-13 years in Seoul, Korea, in 2008. The diagnostic criteria of the International Study of Asthma and Allergies in Childhood were applied in this study. Adjustments were performed for age, gender, maternal education, smoking in the household, relocation to a new house within 1 year of birth, and parental history of atopic disease. After adjustment for confounders, age and duration of maternal education were found to be inversely associated with the prevalence of AD. Among subjects aged ≤5 years, the prevalence of AD was positively associated with the duration of breast-feeding (p < 0.001). However, there was no significant association between AD and breast-feeding among children >5 years of age. Regardless of parental history of atopic diseases, breast-feeding >12 months was a significant risk factor for AD. The effect of breast-feeding differed by age group. Prolonged breast-feeding increased the risk of AD in children <5 years of age, regardless of parental history of atopic diseases.

Analysis of the prevalence of and risk factors for atopic dermatitis using an ISAAC questionnaire in 8,750 Korean children.

BACKGROUND: Since 1995, epidemiologic studies of atopic disorders using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire have been performed in many countries, including the Republic of Korea. The prevalence, burden and risk factors of atopic dermatitis were surveyed in these studies, which helped to enhance their comparability among different areas and age groups, as well as to clarify the nature of atopic dermatitis and other atopic disorders. METHODS: From 21 facilities, 8,750 children were enrolled in this cross-sectional study. The data were collected via the Internet using a questionnaire based on the Korean-language version of the ISAAC study format. RESULTS: The prevalence of atopic dermatitis over the previous 12 months was 14.4%. The prevalence in preschool children was significantly higher than in elementary school children. Family history of atopic diseases, diagnosis of allergic conjunctivitis and diagnosis of food allergy were positively associated with atopic dermatitis in both preschool and elementary school children. In addition, raising pets was positively associated with atopic dermatitis in preschool children. In elementary school children, female gender, secondhand smoking, breastfeeding, changing the parents' house to a newly built one during the first year of life, diagnosis of asthma and diagnosis of allergic rhinitis were positively associated with atopic dermatitis. CONCLUSION: The prevalence of atopic dermatitis in preschool and elementary school children in Korea is similar to that of children in other developing countries. The risk factors for atopic dermatitis are different in preschool and elementary school children. More detailed strategies will be necessary to reduce atopic dermatitis in both age groups.

Measuring depression in South Korea: validity and reliability of a brief questionnaire in the Korean Cancer Prevention Study.

OBJECTIVE: To examine the validity and reliability of a new questionnaire for measuring depression in a South Korean population, and then to estimate the prevalence of depression in that country using this tool. METHODS: In total, 742,600 individuals (123,725 women), aged 30-64 years at entry into the Korean Cancer Prevention Study, completed a depression symptom in 1992 (baseline enrollment) and again in 1994. We examined the concurrent validity of the depression questionnaire by relating data from it to known socio-demographic and behavioral correlates of depression; its predictive capacity by relating scores from the questionnaire to the occurrence of future hospitalization for depression; and the test-retest reliability by comparing scores from its administration in 1992 to those in 1994. RESULTS: The prevalence of major depression was 7.5% in men and 10.0% in women. Factors significantly related to major depression were being younger (men), being female, not being married, of lower socioeconomic status, being a smoker, a heavy drinker, and not exercising regularly. Men (hazard ratio; 95% confidence interval: 2.0; 1.8, 2.2) and women (1.6; 1.3, 1.9) with questionnaire-ascertained depression experienced an elevated risk of hospitalization for the disorder during follow-up. The rates of agreement between responses to 1992 and 1994 surveys were 91.3% in men and 88.3% in women. CONCLUSIONS: These findings imply validity of the instrument and support its use in future studies directed at links of depression with somatic disease endpoints. LIMITATION: The questions do not have a specified time frame of reference.

Fasting glucose level and the risk of incident atherosclerotic cardiovascular diseases.

OBJECTIVE: Although diabetes increases the risk of cardiovascular disease (CVD) and mortality, the dose-response relationship between fasting glucose levels below those diagnostic of diabetes with cardiovascular events has not been well characterized. RESEARCH DESIGN AND METHODS: A prospective cohort study of more than one million Koreans was conducted with a mean follow-up of 16 years. A total of 1,197,384 Korean adults with no specific medical conditions diagnosed were classified by baseline fasting serum glucose level. Associations of fasting glucose level with CVD incidence and mortality, stroke incidence and mortality, and all-cause mortality were analyzed using multivariate proportional hazards regression. RESULTS: The relationships between fasting glucose levels and CVD risks generally followed J-shape curves, with lowest risk in the glucose range of 85-99 mg/dL. As fasting glucose levels increased to >100 mg/dL, risks for CVD, ischemic heart disease, myocardial infarction, and thrombotic stroke progressively increased, but risk for hemorrhagic stroke did not. Fasting glucose levels <70 mg/dL were associated with increased risk of all stroke (hazard ratio 1.06, 95% CI 1.01-1.11) in men and (hazard ratio 1.11, 1.05-1.17) in women. CONCLUSIONS: Both low glucose level and impaired fasting glucose should be considered as predictors of risk for stroke and coronary heart disease. The fasting glucose level associated with the lowest cardiovascular risk may be in a narrow range.

The prevalence of atopic dermatitis, asthma, and allergic rhinitis and the comorbidity of allergic diseases in children.

OBJECTIVES: Childhood allergic diseases are a major concern because they lead to a heavy economic burden and poor quality of life. The purpose of this study was to investigate the prevalence of childhood atopic dermatitis, asthma, allergic rhinitis, and the comorbidity of allergic diseases in Seoul, Korea. METHODS: We conducted a cross-sectional survey between May and October 2010 to evaluate the prevalence of childhood allergic diseases, including atopic dermatitis, asthma, and allergic rhinitis, using a questionnaire from the International Study of Asthma and Allergies in Childhood group. Each questionnaire was completed by the parent or guardian of a child. RESULTS: In the 31,201 children studied, the prevalence of atopic dermatitis symptoms in the past 12 months was 19.3% in children 0 to 3 years of age, 19.7% in children 4 to 6 years of age, 16.7% in children 7 to 9 years of age, and 14.5% in children 10 to 13 years of age (p for trend < 0.001). The prevalence of asthma in these age groups was 16.5%, 9.8%, 6.5%, and 5.4%, respectively (p for trend < 0.001). The prevalence of allergic rhinitis in these age groups was 28.5%, 38.0%, 38.5%, and 35.9%, respectively (p for trend = 0.043). The percentage of subjects with both atopic dermatitis and asthma, both asthma and allergic rhinitis, or both atopic dermatitis and allergic rhinitis was 2.5%, 4.7%, and 8.7%, respectively. The prevalence of comorbid allergic diseases decreased with age (p for trend < 0.001). CONCLUSIONS: Our study revealed that the prevalence of some allergic diseases, such as atopic dermatitis and asthma, was relatively high in very young children and that all of the principal allergic diseases in children often co-exist.