Heechoul Ohrr

Smoking and cancer risk in Korean men and women.

AbstractObjective: In Korea, male smoking prevalence is among the worlds highest, and mortality rates from smoking-caused cancers, particularly lung cancer, are escalating. This cohort study examined the effects of cigarette smoking on the risk of cancer mortality and incidence, and characterized the relationship of cancer risk with the amount and duration of cigarette smoking. Method: A nine-year prospective cohort study was carried out on 1,212,906 Koreans, 30–95 years of age. The study population includes participants in a national insurance program, who completed a questionnaire on smoking and other risk factors. The main outcome measures were death from cancer and cancer incidence, obtained through record linkage. At baseline, 472,970 men (57.0%) and 20,548 (5.4%) women were current cigarette smokers. Results: In multivariate Cox proportional hazards models, controlling for age, current smoking among men increased the risks of mortality for cancer of the lung (relative risk (RR), 4.6; 95% confidence interval (CI), 4.0–5.3) and other cancers, including larynx, bile duct, esophagus, liver, stomach, pancreas, bladder, and also leukemia. Current smoking among women increased the risk of lung cancer mortality (RR = 2.5, 95% CI = 2.0–3.1). Similar results were found for incidence among men and women. Conclusion: In Korea, smoking is an independent risk factor for a number of major cancers. The findings affirm the need for aggressive tobacco control in Korea in order to minimize the epidemic of smoking-caused disease.

Body mass index and cancer risk in Korean men and women

Obesity is associated with diverse health risks, but the role of body weight (BMI) as a risk factor for all and site‐specific cancers remains controversial and risks for cancer associated with obesity have not been well‐characterized in Asians. Body weight and risk for cancer were examined in a 14‐year prospective cohort study of 1,213,829 Koreans aged 30–95 years insured by the National Health Insurance Corporation who had a biennial medical evaluation in 1992–1995. Incidence rates for all cancers and site‐specific cancers were examined in relation to BMI. Age‐ and smoking‐status adjusted hazard ratios (HR) with 95% confidence intervals (CI) were examined using the Cox proportional hazards model. For both sexes, the average baseline BMI was 23.2 kg/m2, and the association of risk for all‐cancers with BMI was positive. Obese men (BMI ≥ 30 kg/m2) were at increased risk for developing the following cancers: stomach (1.31, 1.05–1.64), colon (1.42, 1.02–1.98), liver (1.63, 1.27–2.10) and gallbladder (1.65, 1.11–2.44). Obese women (BMI ≥ 30 kg/m2) were at increased risk for developing liver cancer (1.39, 1.00–1.94), pancreatic cancer (1.80, 1.14–2.86) and breast cancer among women aged ≥50 years old (1.38, 1.00–1.90). The HRs were comparable in never and ever smokers for all cancers and all specific sites except for lung cancer. For all cancers common to both sexes, the association was significantly weaker (p < 0.01) in females. Our study provides further confirmation of the excess cancer risk associated with obesity. Rising obesity in Asian populations raises concern that increasing numbers of avoidable cancer cases will occur among Asians.

Effect of single dose of SA 14-14-2 vaccine 1 year after immunisation in Nepalese children with Japanese encephalitis: a case-control study

BACKGROUND In July, 1999, a single dose of live-attenuated SA 14-14-2 Japanese encephalitis vaccine was given to children aged 1-15 years in the Terai region of Nepal. Cases of natural infection occurred almost immediately. Our aim was to assess the long-term protective effect of this vaccination. METHODS In 2000, this same population had a second seasonal exposure to the virus. We therefore did a case-control study to measure the prevalence of vaccination against Japanese encephalitis in 35 patients hospitalised for the disease 1 year after immunisation, and in age-sex matched village controls. FINDINGS Of 35 children resident in Bardiya and Banke districts admitted to the Bheri Zonal Hospital with serologically confirmed Japanese encephalitis, only one had been vaccinated in 1999. In 430 age-sex matched village controls, 234 (54.4%) were vaccinated. We calculated a median unbiased estimate of the odds ratio of 0.0155, with lower and upper confidence limits of 0.0004 and 0.0986. The protective effect of vaccine after 12-15 months was 98.5% (CI 90.1-99.2%). INTERPRETATION Our study provides evidence of sustained high protection afforded by one dose of live attenuated SA 14-14-2 vaccine in Nepalese children.

Smoking and risk of tuberculosis incidence, mortality, and recurrence in South Korean men and women.

The authors explored the association of cigarette smoking with tuberculosis incidence, recurrence, and mortality. A 14-year prospective cohort study (1992-2006) was carried out in 1,294,504 South Koreans. Participants were grouped by smoking history, and the authors assessed tuberculosis incidence, mortality, and recurrence risk for each group. Unadjusted and adjusted Cox proportional hazards models were used to investigate the association between smoking history and the 3 outcomes of interest, adjusting for age and alcohol use. Compared with never smokers, current smokers had increased mortality from tuberculosis among both men (adjusted hazard ratio (HR) = 1.6, 95% confidence interval (CI): 1.3, 2.0) and women (HR = 1.6, 95% CI: 1.0, 2.4). Current male smokers had greater risk of incident tuberculosis than former smokers (HR = 1.4, 95% CI: 1.3, 1.5), and risk among current smokers increased with number of cigarettes smoked daily. In females, cigarette smoking was not associated with incident tuberculosis. There was interaction between smoking and sex for incidence (P = 0.00047). The effect of smoking was generally reduced with adjustment for body mass index. Among men, the highest alcohol consumption category (> or =100 g/day) was associated with risk of incident tuberculosis (HR = 1.5, 95% CI: 1.3, 1.7). This study provides longitudinal evidence that smoking increases risk of incident tuberculosis, mortality from tuberculosis, and tuberculosis recurrence.

Sex-age-specific association of body mass index with all-cause mortality among 12.8 million Korean adults: a prospective cohort study

Background: Despite differences in body shape and adiposity characteristics according to sex and age, a single range of healthy weight [body mass index (BMI, kg/m2) of 18.5–24.9) regardless of sex and age has been recommended. The aim of the study is to examine whether the association between BMI and all-cause mortality varies by sex and age, and, if relevant, to estimate sex-age-specific optimal BMIs associated with a minimal risk of death. Methods: A total of 12 832 637 Korean adults aged 18–99 years who participated in health examinations during 2001–04 were followed up until 2013. Hazard ratios of death in sex-age groups were calculated using Cox regression models after adjustment for age, smoking status and known pre-existing illness. Results: During follow-up, 456 175 men and 241 208 women died. Among men, the age-specific optimal BMI was 23.0–25.9 (kg/m2) at 18–34 years, 24.0–27.9 at 45–54 year, and 25.0–28.9 at 65–74 years. Among women, it was 15.5–24.9 at 18–34 years, 21.0–26.9 at 45–54 years and 24.0–28.9 at 65–74 years. Patterns of sex-age-specific association generally did not differ between never-smokers with no known illness and all participants. Progressively increased risks above and below sex-age-specific optimums were observed (reverse J-curve). Smoking had a limited impact on the observed associations. Conclusions: Women had a lower optimal BMI than men, especially at younger ages. The optimal BMI increased with age. Change in optimal BMI with age, however, was more profound in women than in men. Sex-age-specific optimums were generally higher than the current normal weight (BMI of 18.5–24.9), except in women below 50 years. Sex-age-specific guidelines related to body weight may be needed to guide people for better health.

A 5-year follow-up of antibody response in children vaccinated with single dose of live attenuated SA14-14-2 Japanese encephalitis vaccine: Immunogenicity and anamnestic responses☆

Out of 98 subjects who had participated in the 2000 JE vaccination campaign, 69 people were enrolled in the tests of 2004 and 2005 for the evaluation of long term immune response of a single dose of live attenuated SA14-14-2 JE vaccine. 89.9% of study subjects (62/69) had maintained a high level of neutralizing antibody until 2004 as their GMT was measured as 133 (Min 11, Max 2991). Forty-four subjects were still positive in 2005, 5 years after JE vaccination, and their neutralizing antibody positive rate was significantly higher than that of 69 age-sex matched unvaccinated control subjects: 63.8% (44/69) vs. 14.5% (10/69) (P<0.05). Twenty-four subjects (Group 1) who were seronegative for neutralizing antibody at the 2005 test were given a second dose for revaccination in 2006. Also 49 seronegative (Group 2) subjects who were enrolled as a control group in 2005 were given one dose of primary JE vaccine in 2006. Seven days after vaccination, seropositive rate was discovered to be 76.5% (13/17) and 168.52 (Min 38, Max 2173) in Group 1, while no seroconversion in Group 2. On the 30th day, seropositive rate and GMT were 82.4% (14/17) and 392.01 (Min 22, Max 2197) in Group 1, while 75.7% (28/37) and 45.72 (Min 12, Max 505) in Group 2, respectively. We observed the persistence of neutralizing antibody of single dose of live attenuated SA14-14-2 JE vaccine, 89.9% after 4 years and 63.8% after 5 years, and a rapid secondary immune response on the seventh day after booster dose among those who had been seronegative in spite of the first dose of vaccine. Single dose of live JE vaccine could be effective to provide a long-term protection in JE endemic area, where natural boosting is quite probable in the vaccinees. However, further studies should be carried out to support whether one dose of live JE vaccine is sufficient for people in JE non-endemic area.

Body Mass Index and Stroke Mortality by Smoking and Age at Menopause Among Korean Postmenopausal Women

Background and Purpose— The association between body mass index and mortality caused by subtypes of stroke among postmenopausal women in terms of smoking status and age at menopause remains controversial. Methods— The data were derived from a cohort study of 3321 with 17.8 years of follow-up (1985 to 2002). Hazard ratios (HRs) and 95% CIs for strokes as related to body mass index were estimated by Cox proportional hazard models adjusted for age, hypertension, smoking, drinking, occupation, education, self-reported health, and age at menopause. A stratified analysis was conducted by age at menopause and smoking status. Results— The obese group (body mass index ≥27.5 kg/m2) had higher risks of total stroke mortality (HR, 1.59; 95% CI, 1.05 to 2.42) and hemorrhagic stroke mortality (HR, 2.91; 95% CI, 1.37 to 6.19) than the normal weight group (18.5≤ body mass index <23.0). Among ever smokers, the obese group showed significantly increased risks of total stroke mortality (HR, 2.33; 95% CI, 1.00 to 5.43) and ischemic stroke mortality (HR, 7.21; 95% CI, 1.18 to 44.3). Obesity had more effect on stroke mortality among women who experienced menopause at age <50 than women with age ≥50. For the obese group of the former, the HR of total stroke was 2.04 (95% CI, 1.25 to 3.34) and that of hemorrhagic stroke 6.46 (95% CI, 2.42 to 17.25). Conclusions— In this prospective study, obesity raised the risks of total stroke mortality and hemorrhagic stroke mortality among Korean menopausal women. It was more evident with women who experienced menopause at age <50. The obese group of ever smokers was at an increased risk of ischemic stroke mortality.

Agent Orange exposure and disease prevalence in Korean Vietnam veterans: The Korean veterans health study

Between 1961 and 1971, military herbicides were used by the United States and allied forces for military purposes. Agent Orange, the most-used herbicide, was a mixture of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid, and contained an impurity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Many Korean Vietnam veterans were exposed to Agent Orange during the Vietnam War. The aim of this study was to evaluate the association between Agent Orange exposure and the prevalence of diseases of the endocrine, nervous, circulatory, respiratory, and digestive systems. The Agent Orange exposure was assessed by a geographic information system-based model. A total of 111,726 Korean Vietnam veterans were analyzed for prevalence using the Korea National Health Insurance claims data from January 2000 to September 2005. After adjusting for covariates, the high exposure group had modestly elevated odds ratios (ORs) for endocrine diseases combined and neurologic diseases combined. The adjusted ORs were significantly higher in the high exposure group than in the low exposure group for hypothyroidism (OR=1.13), autoimmune thyroiditis (OR=1.93), diabetes mellitus (OR=1.04), other endocrine gland disorders including pituitary gland disorders (OR=1.43), amyloidosis (OR=3.02), systemic atrophies affecting the nervous system including spinal muscular atrophy (OR=1.27), Alzheimer disease (OR=1.64), peripheral polyneuropathies (OR=1.09), angina pectoris (OR=1.04), stroke (OR=1.09), chronic obstructive pulmonary diseases (COPD) including chronic bronchitis (OR=1.05) and bronchiectasis (OR=1.16), asthma (OR=1.04), peptic ulcer (OR=1.03), and liver cirrhosis (OR=1.08). In conclusion, Agent Orange exposure increased the prevalence of endocrine disorders, especially in the thyroid and pituitary gland; various neurologic diseases; COPD; and liver cirrhosis. Overall, this study suggests that Agent Orange/2,4-D/TCDD exposure several decades earlier may increase morbidity from various diseases, some of which have rarely been explored in previous epidemiologic studies.

Reproductive risk factors for cardiovascular disease mortality among postmenopausal women in Korea: the Kangwha Cohort Study, 1985-2005.

Objective:The relationship between reproductive factors and the risk of mortality from cardiovascular disease in postmenopausal women is unclear. In this study, we aimed to investigate this relationship in Korean postmenopausal women. Methods:Subcohort analysis was carried out using the data of 3,257 postmenopausal women (age, ≥55 y at study entry) from the Kangwha Cohort Study who were followed up from 1985 until 2005. Cox proportional hazards models were used to evaluate the associations between reproductive factors and cardiovascular disease mortality. Results:The risk of cardiovascular mortality in women who were 20 to 22 years old at first childbirth was 26% lower (95% CI, 0.60-0.92) than that in women younger than 20 years at first childbirth, after adjustment for age at entry, body mass index, hypertension, drinking, smoking, education, and occupation. Early first childbirth was associated with increased cardiovascular disease mortality (P trend = 0.036). The risk of coronary heart disease mortality was 51% lower in women who were 17 to 18 years old at menarche (95% CI, 0.25-0.95) than that in women who were younger than 17 years at menarche. Conclusions:An inverse relationship between age at first childbirth and the risk of cardiovascular disease mortality exists. In addition, early menarche may be a reproductive risk factor for coronary heart disease mortality.

Binge Drinking and Hypertension on Cardiovascular Disease Mortality in Korean Men and Women: A Kangwha Cohort Study

Background and Purpose— The purpose of this study was to examine combined effects of hypertension and binge drinking on the risk of mortality from cardiovascular disease in Koreans. Methods— This study followed a cohort of 6100 residents in Kangwha County, aged ≥55 years as of March 1985, for cardiovascular mortality for 20.8 years up to December 31, 2005. We calculated hazard ratios (HRs) for cardiovascular mortality by blood pressure and binge drinking habits using the Cox proportional hazard model. Binge drinkers and heavy binge drinkers were defined as having ≥6 drinks on 1 occasion and ≥12 drinks on 1 occasion. Results— After adjusting for total alcohol consumption, male heavy binge drinkers with Grade 3 hypertension had a 12-fold increased risk of cardiovascular mortality (HR, 12.7; 95% CI, 3.47 to 46.5), whereas male binge drinkers with Grade 3 hypertension had a 4-fold increased risk of cardiovascular mortality (HR, 4.41; 95% CI, 1.38 to 14.1) when compared with nondrinkers with normal blood pressure. However, in considering separate effects of heavy binge drinking and hypertension on the risk of cardiovascular mortality, HRs were rather low (HR of heavy binge drinkers, 1.88, 1.10 to 3.20; HR of hypertensives, 2.00, 1.70 to 2.35) compared with nondrinkers with normal blood pressure. Conclusions— Binge drinkers and heavy binge drinkers with Grade 3 hypertension showed a marked increase in cardiovascular mortality risk. Even after adjusting for total alcohol consumption, the former revealed 4.41 and the latter indicated 12.7 of HR for the risk of cardiovascular mortality.