Hyun Ja Kim

Dietary factors and gastric cancer in Korea: A case-control study

To assess gastric cancer (GC) risk in relation to dietary intake in Korea, a case‐control study was performed. Trained dietitians interviewed 136 patients diagnosed with GC, and the same number of controls were selected by matching sex, age and hospital. A significant decrease in GC risk was observed with increased intake of Baiechu kimchi (prepared with salted Chinese cabbage and red pepper, etc.), Baiechu kimchi‐stew, garlic, mushroom and soybean milk. On the contrary, a significant increase in the risk of GC was observed with increased intake of cooked rice with bean, charcoal grilled beef, pollack soup, Kkakduki (a kind of kimchi prepared with salted radish and red pepper, etc.), Dongchimi (a kind of kimchi prepared with radish and a large quantity of salt water) and cooked spinach. In food groups, increased intake of soybean products was associated with decreased risk of GC. Intake of citrus fruits rather than total fruits was shown to have a protective effect on the risk of GC, but was not significant. In this study, intake of total vegetables was shown to have a protective effect, whereas high nitrate‐containing vegetables increased the risk of GC. In conclusion, our study suggests that the risk of GC decreased with high consumption of fresh vegetables and fruits, whereas high consumption of foods rich in nitrate and carcinogenic substances produced during the cooking process increased the risk of GC.

Effect of nutrient intake and Helicobacter pylori infection on gastric cancer in Korea: a case-control study.

Abstract: To examine the effects of dietary factor and Helicobacter pylori (H. pylori) infection with emphasis on vitamin intake on the risk of gastric cancer (GC), we conducted a case-control study in South Korea, a high-risk area for GC. Trained dietitians interviewed 136 cases histologically diagnosed with GC. An equal number of hospital controls was selected by matching sex and age. High dietary intakes of vegetable fat [odds ratio (OR) = 0.35; 95% confidence interval (CI) = 0.15-0.83], folate (OR = 0.35; 95% CI = 0.13-0.96), and antioxidants, such as vitamin A (OR = 0.34; 95% CI = 0.13-0.83), β-carotene (OR = 0.33; 95% CI = 0.13-0.82), vitamin C (OR = 0.26; 95% CI = 0.09-0.72), and vitamin E (OR = 0.41; 95% CI = 0.17-1.01), were shown to have a protective effect on GC risk using a multivariate model adjusting for foods significantly related to GC in our previous study (charcoal grilled beef, spinach, garlic, mushroom, and a number of types of kimchi) and supplement use. When stratified according to H. pylori infection, high intakes of vitamin C (OR = 0.10; 95% CI = 0.02-0.63) and vitamin E (OR = 0.16; 95% CI = 0.03-0.83) exhibited highly significant inverse associations with GC among the H. pylori-infected subjects compared with noninfected individuals. GC risk was significantly decreased only when consumption levels for two of these vitamins were high. Our findings suggest that high intake of antioxidant vitamins contribute to the reduction of GC risk and that GC risk in Korea may be decreased by encouraging those with H. pylori infection to increase their intake of antioxidant vitamins.

Diet and Cancer Risk in the Korean Population: A Meta- analysis

Many studies have found links between diet and cancer. The summary estimates of the association between dietary factors and cancer risk were investigated using previously reported studies of the Korean population. Gastric cancer risk was inversely associated with the high intake of soy foods [OR (95% CI): 0.32 (0.25-0.40) for soybean, 0.56 (0.45-0.71) for soybean curd, and 0.67 (0.46-0.98) for soymilk], allium vegetables [OR (95% CI): 0.37 (0.26-0.53) for green onion, 0.54 (0.40-0.73) for garlic, and 0.54 (0.35-0.85) for onion], fruits [OR (95% CI): 0.61 (0.42-0.88)], and mushrooms [OR (95% CI): 0.43 (0.21-0.88)]. Salt and Kimchi were associated with an increased gastric cancer risk [OR (95% CI): 1.92 (1.52-2.43) and 2.21 (1.29-3.77), respectively]. Colorectal cancer risk was positively associated with meat intake [OR (95% CI): 1.25 (1.15-1.36)]. Total soy products, soybean curd, and soymilk showed an inverse association with breast cancer risk [OR (95% CI): 0.61 (0.38-0.99), 0.47 (0.34-0.66), and 0.75 (0.57-0.98), respectively]. Green/yellow and light colored vegetables were associated with a reduced risk of breast cancer [OR (95% CI): 0.34 (0.23-0.49) and 0.44 (0.21-0.90), respectively]. Mushroom intake was inversely associated in pre-menopausal women only [OR (95% CI): 0.47 (0.26-0.86)]. In conclusion, soy foods, fruits and vegetables might reduce cancer risk in the Korean population. High salt food might be risk factor for gastric cancer, and intake of high amount of meat might cause colorectal cancer.

Trends in the prevalence of major cardiovascular disease risk factors among Korean adults: Results from the Korea National Health and Nutrition Examination Survey, 1998–2012

BACKGROUND Mortality from coronary heart disease in Korea has increased continuously, but there are few comprehensive national data on trend in the prevalence of risk factors for cardiovascular disease in this population. We examined the trends in the prevalence of major risk factors for cardiovascular disease, including smoking, obesity, hypertension, diabetes, and hypercholesterolemia, from 1998 through 2012 in a representative Korean population. METHODS Using data from the Korea National Health and Nutrition Examination Survey I (1998) to V (2010-2012), we selected the adults aged≥30 yr who participated in both a health examination and health interview survey. RESULTS From 1998 to 2012, significant decrease in the prevalence of hypertension was observed in both men (32.5 to 31.5%) and women (26.9 to 24.3%). Smoking rates decreased only in men (65.1 to 47.0%), whereas the prevalence of diabetes did not change over time. Conversely, the prevalence of hypercholesterolemia significantly increased from 7.2% to 12.6% for men and from 8.4% to 14.9% for women, whereas the rates of awareness and treatment for hypercholesterolemia were relatively lower than that of hypertension and diabetes. During the period, prevalence of obesity significantly increased from 26.8% to 38.1% only in men. CONCLUSIONS The increased prevalence of hypercholesterolemia and obesity may have contributed to the increasing trend in the mortality from coronary heart disease in Korea. Further population-based surveillance of blood cholesterol levels and obesity needs to be performed, and national strategies for improvement of these factors should be established in Korea.

Fresh and pickled vegetable consumption and gastric cancer in Japanese and Korean populations: a meta-analysis of observational studies.

It is widely known that vegetable consumption contributes to reducing the risk of gastric cancer (GC). However, the incidence rates of GC remain high in both Japanese and Korean populations, even though they have a high consumption of total vegetables. This may be due to the fact that Japanese and Koreans mainly consume processed vegetables, such as cooked, salted, or pickled vegetables, rather than fresh vegetables. To determine whether the intakes of fresh and pickled vegetables have different effects on the risk of GC in Japanese and Korean populations, we carried out a meta‐analysis of published epidemiological reports. Eight studies on the consumption of fresh vegetables and 14 studies on the consumption of pickled vegetables related to GC risk were included in this meta‐analysis. Four studies exploring differences in GC risk in men and women were considered separately. We observed that a high intake of fresh vegetables was significantly associated with a decreased risk of GC (overall summary OR = 0.62, 95% CI = 0.46–0.85) but that a high intake of pickled vegetables was significantly associated with an increased risk of GC (overall summary OR = 1.28, 95% CI = 1.06–1.53). The results of this meta‐analysis provide evidence that a high intake of pickled vegetables may increase GC risk and suggest that a high consumption of fresh vegetables, rather than a large total amount of vegetables including pickled vegetables, is important to reduce GC risk. (Cancer Sci 2009)

Association between Helicobacter pylori infection and the risk of gastric cancer in the Korean population : prospective case-controlled study

Background. Gastric cancer is still the most common malignant tumor in Koreans. Although many reports have supported the association of Helicobacter pylori infection and the development of gastric cancer, few studies have been adjusted by variable factors such as age, sex, education, and economic status. Furthermore, most results from areas with a high incidence of gastric cancer, such as China and Korea, have failed to document any relationship between H. pylori infection and gastric cancer. We conducted a prospective case-controlled study, with controls matched for and adjusted by age, sex, education, and economic status, to evaluate the causal relationship between H. pylori infection and gastric cancer in Korean people. Methods. From March 1997 to October 1998, 136 consecutive patients with gastric cancer, diagnosed by endoscopic histology, and 136 age- and sex-matched control subjects, confirmed to be free of gastric cancer by endoscopy during the same period, were enrolled in the study. The presence of H. pylori infection was determined by enzyme immunoassay (EIA) serology test. Results. Seventy-two of the 136 gastric cancer patients (53%) were positive for H. pylori infection and 54 of the 136 control subjects (40%) were positive for H. pylori infection. The odds ratio (OR), adjusted by variable risk factors, such as age, sex, education, and economic status, for gastric cancer in H. pylori-infected patients was 1.82 (95% confidence internal [CI], 1.10–3.00; P = 0.019). The age- and sex-matched OR by conditional logistic regression was 1.6 (95% CI, 1.01–2.53; P = 0.043). Conclusions.H. pylori infection may be one of the important risk factors for the development of gastric cancer in Korea, an area of high prevalence of H. pylori infection and a high incidence of gastric cancer.

Nitrate Intake Relative to Antioxidant Vitamin Intake Affects Gastric Cancer Risk: A Case-Control Study in Korea

Abstract The objective of this study was to determine whether the intake of nitrate relative to antioxidant vitamin rather than absolute intake of nitrate affects the risk of gastric cancer (GC). In a case-control study in Korea using a food frequency questionnaire, trained dietitians interviewed 136 GC cases and an equal number of controls matched by sex and age. As an index of nitrate intake relative to antioxidant vitamins intake, we calculated the nitrate:antioxidant vitamin consumption ratio. The mean daily nitrate intake from foods was very high in our subjects. Higher absolute intake of nitrate was not associated with GC risk [odds ratios (OR) = 1.13; 95% confidence interval (CI) = 0.42–3.06]. However, the GC risk distinctly increased as the nitrate:antioxidant vitamin consumption ratio increased, particularly with higher nitrate:vitamin E (OR = 2.78; 95% CI = 1.01–7.67) and nitrate:folate ratios (OR = 3.37; 95% CI = 1.28–8.87). Therefore, GC risk was influenced by the intake of nitrate relative to antioxidant vitamins. Our results suggest that a decrease in the intake of nitrate relative to antioxidant vitamins is considerably more effective in reducing GC risk than either a lower absolute intake of nitrate or a higher intake of antioxidant vitamins alone.

[The prevalence of atrophic gastritis and intestinal metaplasia according to gender, age and Helicobacter pylori infection in a rural population].

OBJECTIVES The objective of this study was to evaluate the prevalence of atrophic gastritis and intestinal metaplasia according to gender, age and Helicobacter pylori infection in a rural population in Korea. METHODS Between April 2003 and January 2007, 713 subjects (298 men and 415 women, age range: 18-85) among the 2,161 adults who participated in a population-based survey received gastrointestinal endoscopy. All the subjects provided informed consent. Multiple biopsy specimens were evaluated for the presence of atrophic gastritis and intestinal metaplasia. The presence of Helicobacter pylori was determined using CLO and histology testing. RESULTS The age-adjusted prevalence of atrophic gastritis was 42.7% for men and 38.1% for women and the prevalence of intestinal metaplasia was 42.5% for men and 32.7% for women. The prevalence of atrophic gastritis and intestinal metaplasia increased significantly with age for both men and women (p for trend<0.001). The age-adjusted prevalence of Helicobacter pylori was similar for men (59.0%) and women (56.7%). The subjects with Helicobacter pylori infection showed a significantly higher prevalence of intestinal metaplasia (44.3%) compared with that (26.8%) of the noninfected subjects (p<0.001). However, the prevalence of atrophic gastritis was not statistically different between the Helicobacter pylori-infected subjects and the noninfected individuals. CONCLUSIONS Our findings suggest that the prevalence of atrophic gastritis and intestinal metaplasia is higher for a Korean rural population than that for a Western population; this may be related to the high incidence of gastric cancer in Koreans. Especially, the prevalence of intestinal metaplasia was high for the subjects with Helicobacter pylori infection. The multistep process of gastric carcinogenesis and the various factors contributing to each step of this process need to be determined by conducting future follow-up studies.

Aquaporin7 expression during perinatal development of mouse brain

Emerging evidence suggests that brain aquaporins (AQPs) play important roles in the dynamic regulation of brain water homeostasis and the production of cerebrospinal fluid (CSF) under normal, as well as pathological, conditions. To date, the spatiotemporal expression patterns of AQP1, 4, and 9 have been elucidated in brain tissues. However, the expression of AQP7, an aquaglyceroporin associated with brain development, has not been shown. In the present study, we examined expression of AQP7 during perinatal and adult brain development in the mouse. Throughout brain development, the immunoreactivity of AQP7 was largely found in the choroid plexus (CP). AQP7 immunoreactivity in ependyma (Ep), pia, and blood vessels (BV) was increased during perinatal to postnatal development. Cells in the different layers of cerebral cortex became a little positive for AQP7 immunoreactivity during postnatal development. Optimized semi-quantitative RT-PCR and Western blot analysis revealed that AQP7 mRNA and protein levels increased during perinatal development of brain. To our knowledge, this is the first report on the pattern of AQP7 expression in brain tissues. These results suggest that AQP7 is an important structural element in the choroid plexus and is possibly involved in the production of CSF during brain development in mice.

Major Determinants of Serum Homocysteine Concentrations in a Korean Population

The objective of this study was to identify the factors that determine serum homocysteine concentrations in Korean population. In a community-based study, 871 participants completed detailed questionnaires and physical examination. We found that increased age, male sex, family history of stroke, deficiencies of serum folate and vitamin B12, and elevated serum creatinine significantly increased the risk of hyperhomocysteinemia. However, hormonal and behavioral factors (smoking, alcohol drinking, coffee consumption, and sedentary time) were not associated with the risk of hyperhomocysteinemia. The risk of hyperhomocysteinemia was steeply increased in subjects with two or more risk factors among four selected risk factors (deficiencies of serum folate and vitamin B12, elevated creatinine, and family history of stroke) compared to subjects who did not have any risk factors, especially subjects over the age of 65 yr (odds ratio [OR], 33.5; 95% confidence interval [CI], 3.71-302.0 in men; OR, 39.2; 95% CI, 7.95-193.2 in women). In conclusion, increased age, male sex, family history of stroke, deficiencies of serum folate and vitamin B12, and elevated serum creatinine are important determinants of serum homocysteine concentrations with interaction effects between these factors.