Effects of Socio-demographic Factors on the Decreasing Trend in the Sex Ratio at Birth in Korea, 1997-2017 / 예방의학회지

Objectives@#This study investigated the effects of socio-demographic factors on the decreasing trend in the sex ratio at birth from 1997 to 2017 in Korea. @*Methods@#Data from 10 349 602 live births registered with Statistics Korea from 1997 to 2017 were analyzed. The secondary sex ratio (SSR), defined as the ratio of male to female live births, during the study period (1997-1999 [phase I], 2000-2002 [phase II], 2003-2005 [phase III], 2006-2008 [phase IV], 2009-2011 [phase V], 2012-2014 [phase VI], and 2015-2017 [phase VII]) was calculated according to selected socio-demographic factors, such as parental age, education, occupation, and birth order. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals for a male birth after adjusting for potential confounders. @*Results@#The SSR gradually decreased from 1.10 (in 1998-2000 and 2002) to 1.05 (in 2013-2016). While a decreasing trend in the SSR was not noted among first births, male-biased sex ratios were prominent among third and higher-order births, for which the highest SSR was 1.46 in 1998. Higher birth order was significantly associated with an excess of male births in phases I-VI (≥third vs. first, OR range, 1.03 to 1.35). Advanced maternal age was significantly associated with an excess of female births in phases II, III, and V (≥40 vs. 20-24 years, OR range, 0.92 to 0.95). @*Conclusions@#This study demonstrated that advanced maternal age and reduction of the artificially-biased SSR among third and higher-order births may partially explain the decreasing trend in the SSR from 1997 to 2017 in Korea.

Impact of Changes in Maternal Age and Parity Distribution on the Increasing Trends in the Low Birth Weight and Very Low Birth Weight Rates in South Korea, 2005-2015 / 예방의학회지

OBJECTIVES: The aim of this study was to evaluate the impact of shifts in maternal age and parity on the increasing trends in the low birth weight (LBW) and very low birth weight (VLBW) rates from 2005 to 2015 in South Korea. METHODS: Data from 4 993 041 live births registered with Statistics Korea during the period between 2005 and 2015 were analyzed. Applying a modified standardization method, we partitioned the total increment in the LBW and VLBW rates into (1) the increase in the LBW and VLBW rates due to changes in the maternal age and parity distribution (AP-dis) and (2) the increase due to changes in the age-specific and parity-specific rates (AP-spe) of LBW and VLBW for singleton and multiple births, respectively. RESULTS: During the study period, the total increment in the LBW and VLBW rates was 1.43%p and 0.25%p, respectively. Among singleton births, changes in the AP-dis accounted for 79% (0.34%p) and 50% (0.06%p) of the total increment in the LBW and VLBW rates, respectively. Meanwhile, among multiple births, changes in the AP-dis did not contribute to the increase in the LBW and VLBW rates, with 100% of the increase in the LBW (1.00%p) and VLBW (0.13%p) rates being attributed to changes in the AP-spe. CONCLUSIONS: This study demonstrated that shifts in maternal age and parity were prominent contributors to the increase in the LBW and VLBW rates among singleton births between 2005 and 2015 in South Korea.

Impact of Changes in Maternal Age and Parity Distribution on the Increasing Trends in the Low Birth Weight and Very Low Birth Weight Rates in South Korea, 2005-2015 / 예방의학회지

OBJECTIVES@#The aim of this study was to evaluate the impact of shifts in maternal age and parity on the increasing trends in the low birth weight (LBW) and very low birth weight (VLBW) rates from 2005 to 2015 in South Korea.@*METHODS@#Data from 4 993 041 live births registered with Statistics Korea during the period between 2005 and 2015 were analyzed. Applying a modified standardization method, we partitioned the total increment in the LBW and VLBW rates into (1) the increase in the LBW and VLBW rates due to changes in the maternal age and parity distribution (AP-dis) and (2) the increase due to changes in the age-specific and parity-specific rates (AP-spe) of LBW and VLBW for singleton and multiple births, respectively.@*RESULTS@#During the study period, the total increment in the LBW and VLBW rates was 1.43%p and 0.25%p, respectively. Among singleton births, changes in the AP-dis accounted for 79% (0.34%p) and 50% (0.06%p) of the total increment in the LBW and VLBW rates, respectively. Meanwhile, among multiple births, changes in the AP-dis did not contribute to the increase in the LBW and VLBW rates, with 100% of the increase in the LBW (1.00%p) and VLBW (0.13%p) rates being attributed to changes in the AP-spe.@*CONCLUSIONS@#This study demonstrated that shifts in maternal age and parity were prominent contributors to the increase in the LBW and VLBW rates among singleton births between 2005 and 2015 in South Korea.

Association of head circumference with cognitive decline and symptoms of depression in elderly: a 3-year prospective study / 영남의대학술지

BACKGROUND@#Brain volume is associated with dementia and depression in the elderly. An easy way to predict relative brain volume is to measure head circumference. In this study, we investigated the relationship between head circumference and cognition as well as depression in a non-demented elderly community.@*METHODS@#Baseline and follow-up surveys were conducted in 2007 and 2010. At baseline, community residents aged 65 years or over (n=382) within a rural area of South Korea were screened for dementia and symptoms of depression and were followed using the same screening battery after 3 years (n=279). Data from anthropometric measurements (head circumference, height, and body weight), demographics, and blood tests were gathered. Neuropsychological tests, including the Korean version of mini-mental state examination (K-MMSE), clinical dementia rating (CDR) including the CDR-sum of boxes, the Korean version of instrumental activities of daily living, and geriatric depression scale (GDS), were performed. None of the 279 subjects followed were demented.@*RESULTS@#Baseline performance on the K-MMSE and GDS was poorer for participants with smaller head circumferences. Follow-up performance on the MMSE was also poorer for participants with smaller head circumferences. Interestingly, participants with smaller head circumference showed worse GDS scores at baseline but on follow-up examination, participants with larger head circumference showed rapid worsening than those with smaller head circumference with marginal significance by ANOVA test. In regression coefficient analysis, GDS decline showed significant difference.@*CONCLUSION@#Head circumference was not associated with cognitive change but was associated with symptoms of depression in non-demented community residents.

Association of head circumference with cognitive decline and symptoms of depression in elderly: a 3-year prospective study / 영남의대학술지

BACKGROUND: Brain volume is associated with dementia and depression in the elderly. An easy way to predict relative brain volume is to measure head circumference. In this study, we investigated the relationship between head circumference and cognition as well as depression in a non-demented elderly community.METHODS: Baseline and follow-up surveys were conducted in 2007 and 2010. At baseline, community residents aged 65 years or over (n=382) within a rural area of South Korea were screened for dementia and symptoms of depression and were followed using the same screening battery after 3 years (n=279). Data from anthropometric measurements (head circumference, height, and body weight), demographics, and blood tests were gathered. Neuropsychological tests, including the Korean version of mini-mental state examination (K-MMSE), clinical dementia rating (CDR) including the CDR-sum of boxes, the Korean version of instrumental activities of daily living, and geriatric depression scale (GDS), were performed. None of the 279 subjects followed were demented.RESULTS: Baseline performance on the K-MMSE and GDS was poorer for participants with smaller head circumferences. Follow-up performance on the MMSE was also poorer for participants with smaller head circumferences. Interestingly, participants with smaller head circumference showed worse GDS scores at baseline but on follow-up examination, participants with larger head circumference showed rapid worsening than those with smaller head circumference with marginal significance by ANOVA test. In regression coefficient analysis, GDS decline showed significant difference.CONCLUSION: Head circumference was not associated with cognitive change but was associated with symptoms of depression in non-demented community residents.

Human semen quality and the secondary sex ratio / 亚洲男科学杂志(英文版)

The aim of this study was to evaluate the association between semen quality and the secondary sex ratio (SSR), defined as the ratio of male to female live births. Our study cohort comprised 227 male partners who were enrolled prior to conception in Michigan and Texas between 2005 and 2009, and prospectively followed through delivery of a singleton birth. The male partners provided a baseline and a follow-up semen sample a month apart. Semen analysis was conducted to assess 27 parameters including five general characteristics, six sperm head measures, 14 morphology measures, and two sperm chromatin stability assay measures. Modified Poisson regression models with a robust error variance were used to estimate the relative risk (RR) and 95% confidence interval (95% CI) of a male birth for each semen parameter, after adjusting for potential confounders. Of the 27 semen parameters, only the percentage of bicephalic sperm was significantly associated with the SSR (2 nd vs 1 st quartile, RR, 0.65, 95% CI, 0.45-0.95, P = 0.03; 4 th vs 1 st quartile, RR, 0.61, 95% CI, 0.38-1.00, P < 0.05 before rounding to two decimal places), suggestive of a higher percentage of bicephalic sperm being associated with an excess of female births. Given the exploratory design of the present study, this preconception cohort study suggests no clear signal that human semen quality is associated with offspring sex determination.

Influence of Asthma on the Longitudinal Trajectories of Cigarette Use Behaviors From Adolescence to Adulthood Using Latent Growth Curve Models / 예방의학회지

OBJECTIVES: While epidemiologic research indicates that the prevalence of risk-taking behaviors including cigarette smoking among young people with asthma is substantial, the longitudinal patterns of cigarette smoking in this vulnerable population have received little attention. The aim of this study was to evaluate differences in the longitudinal trajectories of cigarette use behaviors from adolescence to adulthood between young people with and without asthma. METHODS: Data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) during the years 1994 to 1995 (Wave I, adolescence), 2001 to 2002 (Wave III, young adulthood), and 2007 to 2008 (Wave IV, adulthood) were analyzed (n=12 244). Latent growth curve models were used to examine the longitudinal trajectories of cigarette use behaviors during the transition to adulthood according to asthma status. RESULTS: Regardless of asthma status, the trajectory means of cigarette use behaviors were found to increase, and then slightly decrease from adolescence to adulthood. In total participants, there were no statistically significant differences in initial levels and changes in cigarette use behaviors according to asthma status. However, in select sex and race subgroups (i.e., females and non-whites), former asthmatics showed greater escalation in cigarette use behaviors than did non-asthmatics or current asthmatics. CONCLUSIONS: This study indicated that the changing patterns of cigarette use behaviors during the transition to adulthood among young people with asthma are comparable to or even more drastic than those among young people without asthma.

Differences in Cigarette Use Behaviors by Age at the Time of Diagnosis With Diabetes From Young Adulthood to Adulthood: Results From the National Longitudinal Study of Adolescent Health / 예방의학회지

OBJECTIVES: Previous observations propose that risk-taking behaviors such as cigarette smoking are prevailing among young people with chronic conditions including diabetes. The purpose of this study was to examine whether cigarette smoking is more prevalent among diabetics than non-diabetics and whether it differs by age at the time of diagnosis with diabetes from young adulthood (YAH) to adulthood (AH). METHODS: We used US panel data from the National Longitudinal Study of Adolescent Health (Add Health Study) during the years 2001 to 2002 (Wave III, YAH) and 2007 to 2008 (Wave IV, AH). Multivariate logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of cigarette use behaviors according to age at the time of diagnosis with diabetes, after adjusting for demographic and selected behavioral factors. RESULTS: Of 12 175 study participants, 2.6% reported having been diagnosed with diabetes up to AH. Early-onset diabetics (age at diagnosis or =20 days during the previous 30 days) in YAH (OR, 3.34; 95% CI, 1.27 to 8.79). On the other hand, late-onset diabetics (age at diagnosis > or =13 years) were more likely than non-diabetics to report heavy cigarette smoking (smoking > or =10 cigarettes per day during the previous 30 days) in AH (OR, 1.54; 95% CI, 1.03 to 2.30). CONCLUSIONS: The current study indicated that diabetics are more likely than non-diabetics to smoke cigarettes frequently and heavily in YAH and AH. Effective smoking prevention and cessation programs uniquely focused on diabetics need to be designed and implemented.

Greater prevalence of seropositivity for anti-cyclic citrullinated peptide antibody in unaffected first-degree relatives in multicase rheumatoid arthritis-affected families

BACKGROUND/AIMS: This study determined the prevalence and determinants of seropositivity for rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibody, and anti-mutated citrullinated vimentin (anti-MCV) antibody in unaffected first-degree relatives (FDRs) of rheumatoid arthritis (RA) patients. METHODS: A total of 337 subjects (135 with RA and 202 FDRs) were enrolled in this case-control study. Serum RF, anti-CCP antibody, and anti-MCV antibody were assayed. Subjects in multicase families (> or = 2 affected FDRs within the same family) were identified. Multivariate logistic regression analysis was used to identify risk factors associated with RA-related autoantibodies. RESULTS: Seropositivity for RF, anti-CCP antibody, or anti-MCV antibody was detected in 14.4%, 5.0%, or 13.4% of unaffected FDRs, respectively. Anti-CCP antibody seropositivity was more prevalent in FDRs in multicase families (17.8%) than in those not in multicase families (1.3%, p < 0.0001). Significant correlations between RA-associated autoantibodies were detected in the FDR group (between RF and anti-CCP antibody: r = 0.366, p < 0.0001; between RF and anti-MCV antibody: r = 0.343, p < 0.0001; and between anti-CCP antibody and anti-MCV antibody: r = 0.849, p < 0.0001). After adjustment for age and sex, anti-CCP antibody seropositivity in FDRs was significantly associated with being in a multicase family (odds ratio, 49.8; 95% confidence interval, 5.6 to 441.6). CONCLUSIONS: The association between anti-CCP antibody seropositivity in unaffected FDRs and being in a multicase family suggests that genetic and/or environmental factors may increase the risk for RA development in unaffected FDRs.

Prognostic Factors of the RA Patients with ILD

OBJECTIVE: Interstitial lung disease (ILD) is a common pulmonary manifestation of rheumatoid arthritis (RA), and an important cause of morbidity and mortality in RA. We compared demographic and clinical characteristics of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP) patterns in RA patients and determined the prognostic factors that influence the survival of RA-ILD patients. METHODS: 51 enrolled RA patients (male n=21, female n=30) with ILD underwent HRCT. We categorized ILD into two groups, as the UIP pattern and the NSIP pattern, using HRCT. HRCT scans were scored to investigate the extent of the ILD. We divided the extent of the interstitial lung disease into 4 groups 1~14%, 15~19%, 20~24%, >25%. RESULTS: There were no significant differences between the UIP and NSIP pattern in the clinical characteristics, except for age at the time of the study (RA-NSIP pattern vs RA-UIP pattern 62.3+/-11.7 vs 68.2+/-8.4, p=0.042). There were no significant differences in survival time between the RA-UIP and RA-NSIP pattern (Log rank p=0.985). The extent of ILD on chest HRCT was significantly associated with mortality (HR=1.044, 95% CI 1.019~1.069) and patients that were diagnosed with ILD at an older age (HR=1.109, 95% CI 1.024~1.200) were associated with a worse prognosis. Comparing four groups divided by the extent of the lung disease, there were significant differences in survival estimates (Log-rank p-value<0.001) based on an ILD extent of 15%. CONCLUSION: Our study reveals that the extent of ILD on chest HRCT was found to be significantly associated with poor prognosis of RA-ILD patients.

Prognostic Factors of the RA Patients with ILD

OBJECTIVE: Interstitial lung disease (ILD) is a common pulmonary manifestation of rheumatoid arthritis (RA), and an important cause of morbidity and mortality in RA. We compared demographic and clinical characteristics of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP) patterns in RA patients and determined the prognostic factors that influence the survival of RA-ILD patients. METHODS: 51 enrolled RA patients (male n=21, female n=30) with ILD underwent HRCT. We categorized ILD into two groups, as the UIP pattern and the NSIP pattern, using HRCT. HRCT scans were scored to investigate the extent of the ILD. We divided the extent of the interstitial lung disease into 4 groups 1~14%, 15~19%, 20~24%, >25%. RESULTS: There were no significant differences between the UIP and NSIP pattern in the clinical characteristics, except for age at the time of the study (RA-NSIP pattern vs RA-UIP pattern 62.3+/-11.7 vs 68.2+/-8.4, p=0.042). There were no significant differences in survival time between the RA-UIP and RA-NSIP pattern (Log rank p=0.985). The extent of ILD on chest HRCT was significantly associated with mortality (HR=1.044, 95% CI 1.019~1.069) and patients that were diagnosed with ILD at an older age (HR=1.109, 95% CI 1.024~1.200) were associated with a worse prognosis. Comparing four groups divided by the extent of the lung disease, there were significant differences in survival estimates (Log-rank p-value<0.001) based on an ILD extent of 15%. CONCLUSION: Our study reveals that the extent of ILD on chest HRCT was found to be significantly associated with poor prognosis of RA-ILD patients.

Changes in Dietary Behavior Among Adolescents and Their Association With Government Nutrition Policies in Korea, 2005-2009 / 예방의학회지

OBJECTIVES: This study was conducted to observe recent changes in adolescents' dietary behavior and indirectly evaluate the effects of the government's nutritional policies in Korea. METHODS: We analyzed the secular trends in seven dietary behaviors using the Korea Youth Risk Behavior Web-based Survey data from 2005 to 2009. Through literature review, we included the policies implemented for the improvement of adolescents'dietary behaviors during the same periods. RESULTS: The significant linear trends were observed in all dietary behaviors (p<0.05). Overall, all behaviors except the fruit intake rate were desirably changed during five years but undesirable changes were observed between 2008 and 2009 in all behaviors. Within those periods, several policies were implemented including 'Ban on carbonated-beverages in school', 'Green Food Zone', etc. Despite confirmed evidence of their effects, the policies on individual behavior such as nutrition education didn't influence the prevalence of dietary behaviors because they were conducted to too limited persons. Polices on the school environmental improvement, such as ban on carbonated beverage in school, were more effective because they decreased the exposure of undesirable food environment. However, for effect of Green Food Zone improving community environment we couldn't come to a conclusion because of too short period after full implementation. CONCLUSIONS: Among government nutrition policies conducted from 2005 to 2009, those on environmental improvement, especially in school, were more effective than those on individual behavior. Therefore, the development and implement of policies on school environmental improvement are needed in Korea.

Trends in Cigarette Use Behaviors Among Adolescents by Region in Korea / 예방의학회지

OBJECTIVES: Understanding recent trends in cigarette smoking among adolescents is important in order to develop strategies to prevent cigarette smoking. The aim of this study was to compare recent trends in cigarette smoking for adolescents living in rural areas, small towns and metropolitan cities in Korea. METHODS: The raw data from the Korea Youth Risk Behavior Web-based Survey (KYRBWS) from 2005 to 2009 were used. Data were analyzed by using the method of complex survey data analysis considering complex sampling design. Logistic regression models were used to evaluate significant linear time trends in cigarette smoking. The indicators of cigarette use behaviors were 'current smoking rate', 'frequent smoking rate', 'heavy smoking rate' and 'smoking experience rate before 13 years of age'. All analyses were conducted according to gender. RESULTS: Statistically significant increasing trends in current smoking rate and frequent smoking rate were observed and borderline significant increasing trends in heavy smoking rate were shown among rural boys. Among metropolitan city boys, statistically significant increasing trends were also seen for frequent smoking. Statistically significant decreasing trends in current smoking rate were observed among small town and metropolitan city girls. Smoking experience rate before 13 years of age for rural girls decreased significantly. CONCLUSIONS: Cigarette smoking prevalence among adolescents in the rural areas has increased in the last five years especially among boys. Our findings suggest that anti-tobacco program for adolescents should be conducted primarily for those in rural areas.

Changes in the Distribution of Maternal Age and Parity and Increasing Trends in the Low Birth Weight Rate in Korea Between 1995 and 2005 / 예방의학회지

OBJECTIVES: This study measured the impact of shifts in maternal age and parity on the increase in the low birth weight (LBW) rate in Korea. METHODS: We obtained raw data for all 6 397 945 live births registered at the Korea National Statistical Office between 1995 and 2005. We calculated the proportion of increment in the LBW rate due to changes in the distribution of maternal age and parity (AP-dis) and the proportion due to changes in the age- and parity-specific LBW rate (AP-spe). RESULTS: The LBW rate increased from 3.02% in 1995 to 4.28% in 2005. The multiple birth rate increased from 1.32% to 2.19% during the same period. Of the 1.26% points increment in the LBW rate, 0.64% points occurred among singleton births and 0.62% points occurred among multiple births. Changes in the AP-dis accounted for 50% of the increase in the LBW rate among singleton births, but did not contribute to the increase in the LBW rate among multiple births. The remainder of the total increment in the LBW rate was explained by the increase in the AP-spe. CONCLUSIONS: This study demonstrated that shifts in maternal age and parity among singleton births and increased multiple births were important contributors to the increment in the LBW rate. This study also revealed that the increase in the AP-spe was an equally important contributor as the shifts in maternal age and parity to the increment in the LBW rate among singleton births and was a major contributor among multiple births.

Modifying Effect of Suicidal Ideation on the Relationship Between Asthma and Cigarette Use Behaviors Among Korean Adolescents / 예방의학회지

OBJECTIVES: Although cigarette smoking is known to be related to the exacerbation of asthma symptoms, several studies have indicated that the prevalence of cigarette smoking among asthmatic adolescents is similar to or even higher than that among non-asthmatic adolescents. The aim of this study was to evaluate the relationship between asthma and cigarette use behaviors and whether or not the presence of suicidal ideation modifies this relationship among Korean adolescents. METHODS: We analyzed data from the 2008 Korea Youth Risk Behavior Web-based Survey, which included a nationally representative sample of middle and high school students. Multiple logistic regression models were used to calculate odd ratios and 95% confidence intervals of cigarette use behaviors among current asthmatics, former asthmatics, and non-asthmatics, after adjusting for gender, grade, school records, socioeconomic status, current alcohol use, and suicidal ideation. RESULTS: Of 75 238 study participants, 3.5% were current asthmatics and 4.5% were former asthmatics. Compared with non-asthmatics, asthmatics were more likely to report current cigarette use, frequent and heavy cigarette use, and cigarette use before 13 years of age. There were statistically significant interactions between asthma and suicidal ideation in cigarette use behaviors. CONCLUSIONS: This study demonstrated that asthmatic adolescents are more likely than non-asthmatic adolescents to engage in cigarette use behaviors and the presence of suicidal ideation is an effect modifier of the relationship between asthma and cigarette use behaviors. Particular attention should be paid to the awareness of health risks of cigarette smoking and mental health problems among asthmatic adolescents.

Validity of Self-Reported Height, Weight, and Body Mass Index of the Korea Youth Risk Behavior Web-Based Survey Questionnaire / 예방의학회지

OBJECTIVES: Self-reported anthropometric values, such as height and weight, are used to calculate body mass index (BMI) and assess the prevalence of obesity among adolescents. The aim of this study was to evaluate the validity of self-reported height, weight, and BMI of the Korea Youth Risk Behavior Web-based Survey questionnaire. METHODS: A convenience sample of 137 middle school students and 242 high school students completed a self-administered questionnaire in 2008. Body height and weight were directly measured after self-reported values were obtained from the questionnaire survey. Sensitivity, specificity, and kappa statistics were computed in order to evaluate the validity of the prevalence of obesity (BMI > or = 95th percentile or > or = 25 kg/m2) based on self-reported data. RESULTS: Self-reported weight and BMI tended to be underestimated. Self-reported height tended to be overestimated among middle school females and high school males. Obese adolescents tended to underestimate their weight and BMI and overestimate their height more than non-obese adolescents. The prevalence estimate of obesity based on self-reported data (10.6%) was lower than that based on directly measured data (15.3%). The estimated sensitivity of obesity based on self-reported data was 69.0% and the specificity was 100.0%. The value of kappa was 0.79 (95% confidence interval, 0.70-0.88). CONCLUSIONS: This study demonstrated that self-reported height and weight may lead to the underestimation of BMI and consequently the prevalence of obesity. These biases should be taken into account when self-reported data are used for monitoring the prevalence and trends of obesity among adolescents nationwide.

Test-Retest Reliability of a Questionnaire for the Korea Youth Risk Behavior Web-Based Survey / 예방의학회지

OBJECTIVES: A web-based survey has been administered annually since 2005 throughout Korea to assess the prevalence of adolescent health risk behaviors among middle and high school students. The aim of this study was to evaluate the test-retest reliability of the Korea Youth Risk Behavior Web-based Survey (KYRBWS) questionnaire. METHODS: A convenience sample of 2298 middle and high school students participated in self-administered questionnaire surveys twice, approximately two weeks apart, in 2008. The percent agreement, kappa statistics, and prevalence rates at the first and second surveys were computed for the core subset of 39 self-reported health risk behavior indices of the KYRBWS. RESULTS: Among 39 indices, seven indices had kappas > or = 0.81 and all of the indices had kappas > or = 0.41. Based on non-overlapping 95% confidence intervals, three indices had significantly different prevalence rates between the first and second surveys. In the subgroup analyses by school grade and gender, two indices had significantly different reliability estimates between middle and high school students. There were no significantly different reliability estimates between male and female students, except for one index. CONCLUSIONS: This study demonstrated that the reliability estimates for the KYRBWS questionnaire are varied, but generally reliable over time. The indices with low reliability estimates need to be evaluated further in order to determine whether the indices should be modified or deleted from future versions of the KYRBWS.

Reliability of a Questionnaire for Women's Reproductive History / 예방의학회지

OBJECTIVES: This study was performed to evaluate the reproducibility of a questionnaire concerned with reproductive history and to ascertain which characteristics of the subjects (age, the visit-revisit intervals, education and chronic disease) are associated with good reliability in the Korean Multi-Center Cancer Cohort (KMCC) study. MATERIALS AND METHODS: A total of 19,688 participants were enrolled between 1993 and 2004. Among them, we selected 386 participants who were aged 40 or more and who re-visited within 8 years after the first visit. Reliability was measured by the percent agreement according to error range for the continuous variables and the percent agreement and kappa statistics for the categorical variables. RESULTS: The pregnancy histories were reliable (kappa=0.67) and the reasons for being menopausal among the postmenopausal women were also reliable (kappa=0.92). The percent agreement of the breast-feeding history was high (96.1%), although the kappa statistic was low. For the continuous variables, when the error range of one variable was considered to be reliable, the percent agreement of the age at menarche and the age at the first full term pregnancy was good (69.4% and 83.6%), whereas that of the age at menopause was low (51.5%). The factors associated with high reliability were a younger age, the presence of chronic disease and a short visit-revisit time interval. CONCLUSIONS: The agreements for parity, the reasons for menopause, and the breastfeeding history in the reproductive history questionnaire used in the KMCC were relatively good. The questionnaire for the menarche age and the menopausal age might have lower reliability due to the difference between Korean age and American age. To obtain reliable information, more attention should be given to the items in questionnaire-based surveys, and especially for surveying old-aged women.

Correction: Long Term Trends and the Future Gastric Cancer Mortality in Korea: 1983~2013 / Journal of the Korean Cancer Association, 대한암학회지

This article was published with an error.

Cigarette Smoking, Alcohol Consumption, Tuberculosis and Risk of Lung Cancer: The Korean Multi-center Cancer Cohort Study / 예방의학회지

OBJECTIVES: The aim of this study was to evaluate the roles of cigarette smoking, alcohol consumption, tuberculosis, and their interactions in the risk of lung cancer in a Korean cohort. METHODS: The study subjects comprised 13,150 males and females aged above 20 years old. During the follow up period from 1993 to 2002, 79 lung cancer cases were identified by the central cancer registry and the national death certificate database. Information on cigarette smoking, alcohol consumption and the history of physiciandiagnosed tuberculosis was obtained by interview. Indirect chest X-ray findings were also evaluated to ascertain tuberculosis cases. Cox proportional hazard models were used to estimate relative risks (RR) and 95% confidence intervals (CI) after adjusting for age and gender. RESULTS: Cigarette smoking was statistically significantly associated with an increased risk of lung cancer [for current smokers, RR = 2.33 (95% CI = 1.23 - 4.42) compared to non-smokers]. After further adjustment for cigarette smoking, both alcohol consumption and tuberculosis showed no statistically significant association with the risk of lung cancer [for current drinkers, RR = 0.80 (95% CI = 0.48 - 1.33) compared to non-drinkers] [for tuberculosis cases, RR = 1.17 (95% CI = 0.58 - 2.36) compared to noncases]. There was no statistically significant interaction between cigarette smoking and alcohol consumption (pinteraction = 0.38), or cigarette smoking and tuberculosis (p-interaction = 0.74). CONCLUSIONS: Although cigarette smoking was confirmed as a risk factor of lung cancer in this cohort study, this study suggests that alcohol consumption and tuberculosis may not be associated with the risk of lung cancer.