The Effect of Breastfeeding Duration and Parity on the Risk of Epithelial Ovarian Cancer: A Systematic Review and Meta-analysis / 예방의학회지

OBJECTIVES: We conducted a systematic review and meta-analysis to summarize current evidence regarding the association of parity and duration of breastfeeding with the risk of epithelial ovarian cancer (EOC). METHODS: A systematic search of relevant studies published by December 31, 2015 was performed in PubMed and EMBASE. A random-effect model was used to obtain the summary relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: Thirty-two studies had parity categories of 1, 2, and ≥3. The summary RRs for EOC were 0.72 (95% CI, 0.65 to 0.79), 0.57 (95% CI, 0.49 to 0.65), and 0.46 (95% CI, 0.41 to 0.52), respectively. Small to moderate heterogeneity was observed for one birth (p13 months. The summary RRs were 0.79 (95% CI, 0.72 to 0.87), 0.72 (95% CI, 0.64 to 0.81), and 0.67 (95% CI, 0.56 to 0.79), respectively. Only small heterogeneity was observed for <6 months of breastfeeding (p=0.17; Q=18.79, I²=25.5%). Compared to nulliparous women with no history of breastfeeding, the joint effects of two births and <6 months of breastfeeding resulted in a 0.5-fold reduced risk for EOC. CONCLUSIONS: The first birth and breastfeeding for <6 months were associated with significant reductions in EOC risk.

Effect of Sodium Benzoate on Change of Urinary Hippuric Acid and Methyl Hippuric Acid among Workers Coexposed to Toluene and Xylene / 대한산업의학회지

OBJECTIVES: This study was performed to investigate the effect of drink containing sodium benzoate on the change of urinary hippuric acid (UHA) and methyl hippuric acid (UMHA) excretion among workers coexposed to low toluene and xylene. METHODS: Study subjects were 55 male shipbuilders who were divided into 3 groups; nonexposed group (n=10, who were not exposed to organic solvent and had drunk sodium benzoate), exposed A group (n=24, who were coexposed to toluene and xylene, and had drunk sodium benzoate), and exposed B group (n=21, who were coexposed to toluene and xylene, and had not drunk sodium benzoate). The study methodology consisted of questionnaire survey, urinary analysis for metabolites of toluene and xylene before and after drinking with or without sodium benzoate, and personal air sampling of toluene and xylene. RESULTS: Before drinking, there was no significant difference in UHA or UMHA between the exposed A and B groups. After 1.5 hour of drinking, UHA of the exposed A group was significantly higher than that of the exposed B group. After 3 hours, however, UHA of the exposed A group was decreased to the level of the exposed B group, regardless of the ambient toluene level. UMHA exhibited no significant difference between the exposed A and B groups regardless of time and ambient toluene level. The regression model showed that drinking of sodium benzoate was positively correlated with UHA after 1.5 hours of drinking, but not after 3 hours. In addition, sodium benzoate didn't affect UMHA. CONCLUSIONS: This study showed that sodium benzoate initially increased UHA temporally but that its effect disappeared after 3 hours. In the medical examination of toluene exposure workers, the ingestion of drink containing sodium benzoate should be forbidden during the 3 hours prior to urinary sampling.

Sero-prevalence of Hepatitis B Virus Surface Antigen and Antibody in High School Students in Chungju-city / 한국역학회지

OBJECTIVES: Since Korea has been known to be one of the endemic area for hepatitis B virus(HBV) infection, vaccination for HBV has been recommended for all neonates in Korea. After starting vaccination in 1983, the change of sero-positivity of HBsAg and HBsAb is expected. This study was carried out to investigate the seropositive rate of hepatitis B virus surface antigen and antibody in high school freshmen students in Chungju-city. METHODS AND MATERIALS: From 1998 to 2001, a total of 11,735 who were born in 1982 to 1986, were enrolled in this study. HBsAg and anti-HBs were tested by reversed passive hemagglutination and passive hemagglutination, respectively. PESULTS: The study population was 11,735 students who were composed of 5,813 males (49.6%) and 5,914 females (50.4%). The HBsAg sero-positivity of male and female students was 3.25% (n=381) and 2.59% (n=153) respectively. The anti-HBs sero-positivity of male and female students was 62.2% (n=3,154) and 64.1% (n=2,969) respectively. There are significant difference observed in comparison of HBsAg and anti-HBs seropositivity according to sex (p<0.05). From 1982 to 1986 on birth year, anti-HBs sero-positivity has been increased significantly from 63.3% to 73.3%. But the change of HBsAg sero-positivity has not been changed significantly. CONCLUSIONS: As compared with previous studies of HBsAg and anti-HBs, the sero-positive rate of HBsAg has not been changed but that of HBsAb has been increased significantly. This result revealed that the effect of HBV vaccination program was successful.