Yunhee Lee

Development of Korean Smartphone Addiction Proneness Scale for Youth

This study developed a Smartphone Addiction Proneness Scale (SAPS) based on the existing internet and cellular phone addiction scales. For the development of this scale, 29 items (1.5 times the final number of items) were initially selected as preliminary items, based on the previous studies on internet/phone addiction as well as the clinical experience of involved experts. The preliminary scale was administered to a nationally representative sample of 795 students in elementary, middle, and high schools across South Korea. Then, final 15 items were selected according to the reliability test results. The final scale consisted of four subdomains: (1) disturbance of adaptive functions, (2) virtual life orientation, (3) withdrawal, and (4) tolerance. The final scale indicated a high reliability with Cronbachs α of .880. Support for the scales criterion validity has been demonstrated by its relationship to the internet addiction scale, KS-II (r  =  .49). For the analysis of construct validity, we tested the Structural Equation Model. The results showed the four-factor structure to be valid (NFI  =  .943, TLI  =  .902, CFI  =  .902, RMSEA  =  .034). Smartphone addiction is gaining a greater spotlight as possibly a new form of addiction along with internet addiction. The SAPS appears to be a reliable and valid diagnostic scale for screening adolescents who may be at risk of smartphone addiction. Further implications and limitations are discussed.

The association between the preoperative serum levels of lipocalin-2 and matrix metalloproteinase-9 (MMP-9) and prognosis of breast cancer

BackgroundAlthough a number of experimental studies have suggested the role of lipocalin-2 (LCN2) and matrix metalloproteinase-9 (MMP-9) in breast cancer progression, limited numbers of epidemiological studies have examined the relationship between the levels of lipocalin-2 and MMP-9 and breast cancer survival.MethodsPreoperative serum levels of lipocalin-2 and MMP-9 were measured in 303 breast cancer patients and 74 healthy controls recruited between 2004 and 2007. We examined the association between lipocalin-2 and MMP-9 levels and disease-free survival (DFS) using Cox proportional hazard regression model.ResultsThe serum levels of lipocalin-2 and MMP-9 were not significantly different between patients and controls (P > 0.05). Elevated lipocalin-2 and MMP-9 levels were associated with reduced DFS of breast cancer ( Ptrend = 0.029 and Ptrend = 0.063, respectively). When lipocalin-2 and MMP-9 levels were categorized based on the combined risk score, patients with higher levels of both lipocalin-2 and MMP-9 exhibited poor DFS compared to patients with lower levels (Ptrend = 0.004). Furthermore, these effects were profound in patients with BMI less than 25 kg/m2 (adjusted hazard ratio (aHR), 3.17; 95% confidence intervals (CI), 1.66-6.06, Ptrend < 0.001) or lymph-node negative breast cancer (aHR, 5.36; 95% CI, 2.18-13.2, Ptrend < 0.001).ConclusionsOur study suggests that the elevated levels of lipocalin-2 and MMP-9 are associated with reduced breast cancer survival, particularly in patients with lower BMI and lymph-node negative breast cancers.

What Are the Major Determinants in the Success of Smoking Cessation: Results from the Health Examinees Study

Understanding mechanisms underlying smoking-related factors should be prioritized in establishing smoking prevention and cessation policy. The aim of this study was to identify factors significantly associated with smoking initiation and/or smoking cessation as well as the most important determinants of successful smoking cessation in a developed non-Western setting. Based on multiple logistic regression models, the odds ratios (ORs) for smoking initiation and cessation were estimated among males (N = 24,490) who had participated in the Health Examinees (HEXA) study. The Cox proportional hazards regression model was used to assess the association between selected predictors of smoking cessation and the likelihood of reaching this goal. Finally, Kaplan–Meier curves were constructed to illustrate the distribution of time from age at smoking initiation to age at smoking cessation. We found that the ORs for successfully quitting smoking increased with age, married status, educational achievement, having a non-manual job, drinking cessation and disease morbidity. Those exposed to secondhand smoking showed less likelihood of quitting smoking. A continual decrease in the ORs for successfully quitting smoking was observed according to increased smoking duration, smoking dose per day and lifetime tobacco exposure (p trend <0.001). Among the selected predictors, lifetime tobacco exposure, educational attainment, alcohol drinking status and birth cohort were the major determinants in the success of smoking cessation. Our findings suggest that lifetime tobacco exposure, educational attainment, alcohol drinking status and birth cohort can determine success in smoking cessation. Public interventions promoting a smoke-free environment are needed to reinforce discouraging the initiation of, reducing, and quitting cigarette smoking.

Preoperative serum levels of matrix metalloproteinase-2 (MMP-2) and survival of breast cancer among Korean women

Background: Matrix metalloproteinase-2 (MMP-2) has been thought of as a predictor of recurrence or metastasis risk or prognostic markers in cancer. We evaluated whether preoperative serum levels of MMP-2 work as a prognostic biomarker in breast cancer prognosis. Methods: Preoperative serum levels of MMP-2 were measured with ELISA in 303 patients with histologically confirmed breast cancer. The median follow-up time for all patients was 4.24 years. The relationship of MMP-2 to survival was investigated using Cox proportional hazard regression model adjusted for the tumor–node–metastasis (TNM) stage and estrogen receptor (ER) status. Results: In the multivariate analysis, disease-free survival (DFS) was worse among patients with the third tertile of MMP-2 level than with the first tertile of MMP-2 level [hazard ratio, 1.80; 95% confidence interval (CI), 1.04–3.11; P = 0.04]. However, when the patients were stratified by age, ER status, histologic grade, and nuclear grade, inverse correlation was shown between serum MMP-2 levels and prognostic factors, and the associations between MMP-2 and DFS were only significant among patients with poor prognostic factors (HR, 2.75; 95% CI, 1.32–5.73 in ER-negative; HR, 2.90; 95% CI, 1.42–5.92 in histologic grade III; and HR, 2.61; 95% CI, 1.26–5.39 in nuclear grade III). Conclusions: Our results suggest that the preoperative serum levels of MMP-2 were associated with the survival in patients with breast cancer in ER-negative, higher histologic grade, or higher nuclear grade breast cancers. Impact: Our results indicate that serum levels of MMP-2 may play a role as prognostic biomarker in breast cancer survival. Cancer Epidemiol Biomarkers Prev; 21(8); 1371–80. ©2012 AACR.

Genetic variants in interleukin-2 and risk of lymphoma among children in Korea.

To estimate the genetic susceptibility for childhood lymphoma, we conducted an association study for 23 cases and 148 controls. Total 1536 tag single nucleotide polymorphisms (SNPs) were selected in 138 candidate gene regions related to immune responses, apoptosis, the cell cycle, and DNA repair. Twelve SNPs were significantly associated with the risk of lymphoma (P(trend)<0.05) in six genes (IL1RN, IL2, IL12RB1, JAK3, TNFRSF13B, and XRCC3). The most significant association was seen for IL2 variant rs2069762 (OR(TG+GG) vs. TT=3.43 (1.29-9.11), P(trend)=0.002, minP=0.005). These findings suggest that common genetic variants in IL2 might play a role in the pathogenesis of childhood lymphoma.

Subsequent Risk of Metabolic Syndrome in Women With a History of Preeclampsia: Data From the Health Examinees Study

Background To investigate whether preeclampsia is independently associated with risk of future metabolic syndrome and whether any such primary associations are modified by different ages at first pregnancy. Methods Based on the Health Examinees Study, a cross-sectional analysis was conducted. Data of women (n = 49 780) who had experienced at least 1 pregnancy during their lifetime and had never been diagnosed with any metabolic disorder before their pregnancy were analyzed using multiple logistic regression models. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated after adjusting for age, lifestyle characteristics, and reproductive factors. A stratified analysis was also conducted to estimate the extent of the primary association between preeclampsia and future metabolic syndrome by age at first pregnancy. Results Women with a history of preeclampsia had significantly increased odds of developing metabolic syndrome (adjusted OR 1.23; 95% CI, 1.12–1.35), central obesity (adjusted OR 1.36; 95% CI, 1.25–1.47), elevated blood pressure (adjusted OR 1.53; 95% CI, 1.41–1.67), or elevated fasting glucose (adjusted OR 1.13; 95% CI, 1.03–1.25) in later life. In the stratified analysis, women who first became pregnant at ages >35 years and had preeclampsia were found to be at significantly increased likelihood of metabolic syndrome later in life (adjusted OR 4.38; 95% CI, 1.62–11.9). Conclusions Our findings suggest that preeclampsia increases the risk of metabolic syndrome in later life, and late age at first pregnancy can further exacerbate this risk.

Prognosis of breast cancer is associated with one-carbon metabolism related nutrients among Korean women.

BackgroundThe 5-year survival rate for breast cancer among Korean women has increased steadily; however, breast cancer remains the leading cause of cancer mortality among women. One-carbon metabolism, which requires an adequate supply of methyl group donors and B vitamins, may affect the prognosis of breast cancer. This aim of this study was to investigate the associations of dietary intake of vitamin B2, vitamin B6 and folate before diagnosis on the prognosis of breast cancer.MethodsWe assessed the dietary intake using a food frequency questionnaire with 980 women who were newly diagnosed and histopathologically confirmed to have primary breast cancer from hospitals in Korea, and 141 disease progression events occurred. Cox’s proportional hazard regression models were used to estimate the hazard ratio (HR) and 95% confidence interval (95% CI) adjusting for age, education, recruitment sites, TNM stage, hormone status, nuclear grade and total calorie.ResultsThere was no significant association between any one-carbon metabolism related nutrients (vitamin B2, B6 and folate) and the progression of breast cancer overall. However, one-carbon metabolism related nutrients were associated with disease progression in breast cancer patients stratified by subtypes. In ER + and/or PR + breast cancers, no association was observed; however, in ER–/PR– breast cancers, a high intake of vitamin B2 and folate statistically elevated the HR of breast cancer progression (HR = 2.28; 95% CI, 1.20-4.35, HR = 1.84; 95% CI, 1.02-3.32, respectively) compared to a low intake. This positive association between the ER/PR status and progression of the disease was profound when the nutrient intakes were categorized in a combined score (Pinteraction = 0.018). In ER–/PR– breast cancers, high combined scores were associated with a significantly poor DFS compared to those belonging to the low score group (HR = 3.84; 95% CI, 1.70-8.71).ConclusionsIn conclusion, our results suggest that one-carbon related nutrients have a role in the prognosis of breast cancer depending on the ER/PR status.

Short Sleep Duration and Its Correlates among Cancer Survivors in Korea: the Korea National Health and Nutrition Examination Surveys.

BACKGROUND Though a large proportion of cancer survivors are assumed to be commonly affected by sleep disturbance, few studies have focused on short sleep problems and its correlates among Korean cancer survivors. The purpose of this study was to evaluate the prevalence of short sleep in adult cancer survivors from a nationwide population-based sample and to identify risk factors for short sleep duration. MATERIALS AND METHODS Based on the fourth and fifth Korea National Health and Nutrition Examination Surveys (2007-2012), 1,045 cancer survivors and 33,929 non-cancer controls were analyzed. The prevalence of short sleep was compared between these two groups. Associations between short sleep and its correlates were evaluated using multiple logistic regression among cancer survivors: odds ratios (ORs) and 95% confidence intervals (95%CIs) were estimated after adjusting for sociodemographic factors, lifestyle factors, psychological conditions, and cancer-related factors. RESULTS About 8.1% of cancer survivors slept for less than 5 hours per day (6.2% men and 9.3% women), whereas this was the case for only 3.7% of non-cancer controls. Cancer survivors who had the lowest household income level showed a significantly higher likelihood for short sleep (adjusted OR 2.82, 95%CI 1.06-7.54). Self-reported poor health and depressive symptoms were found to be associated with significantly increased likelihood for short sleep in cancer survivors (adjusted OR 3.60, 95%CI 1.40-9.26 and adjusted OR 2.00, 95%CI 1.17-3.42). Gastric cancer survivors had a 3.97-fold increased risk for short sleep (95%CI 1.60-9.90). CONCLUSIONS The prevalence of short sleep occurs at a high rate among the Korean cancer survivors, which may indicate a poorer quality of life and a higher risk of future complications in survivorship. Targeted interventions that can assist cancer survivors to cope with sleep disturbances as well as ensuring psychological stability are warranted to reduce the latent disease burden.

Abstract 4494: Preoperative serum levels of matrix metalloproteinase-2 (MMP-2) and survival of breast cancer among Korean women

Objective: We evaluated whether preoperative serum levels of matrix metalloproteinase-2 (MMP-2) work as a prognostic biomarker in breast cancer prognosis. Methods: Three hundred and three women with histologically confirmed breast cancer were recruited. The follow-up time for all patients was 4.24 years. The MMP-2 levels were quantitatively measured by enzyme-linked immunosorbent assay (ELISA) using the preoperative serum. The relationship of MMP-2 to survival was investigated using Cox9s proportional hazard model adjusted for the TNM stage and estrogen receptor (ER) status. Results: In the multivariate analysis, disease-free survival (DFS) was worse among patients with the third tertile of MMP-2 compared to the first tertile of MMP-2 (hazard ratio (HR)=1.80, 95% confidence interval (CI)=1.04-3.11, P=0.04). Furthermore, when the patients were stratified by histological grade and nuclear grade, the worse DFS was predicted by high levels of MMP-2 (HR=2.90 and 95% CI=1.42-5.92 in histological grade III vs. I-II and HR=2.61 and 95% CI=1.26-5.39 in nuclear grade III vs. I-II). In ER negative patients, high levels of MMP-2 also tended to have a worse prognosis (HR=2.75 and 95% CI=1.32-5.73). Conclusions: Our results suggest that the preoperative serum levels of MMP-2 were associated with the survival of breast cancer as a potential prognostic biomarker. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4494. doi:1538-7445.AM2012-4494

Abstract 641: Prognosis of breast cancer is associated with one-carbon metabolism related nutrients among Korean women

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL The 5-year survival rate for breast cancer has increased from 78% during 1993 to 1995 to 90% during 2004 to 2008 among Korean women. Despite such improvement, breast cancer remains the leading cause of cancer mortality among women. One-carbon metabolism, which requires adequate supply of methyl group donors and B-vitamins, may affect breast cancer prognosis. This study aimed to investigate the associations of dietary intake of vitamin B2, vitamin B6 and folate before diagnosis and breast cancer prognosis. We assessed dietary intake from Food Frequency Questionnaire in 980 women who were newly diagnosed and histopathologically confirmed first primary breast cancer from hospitals located in Seoul, Korea in 2004 to2007 and followed for an average of 5.3 years. Univariate and multivariate analyses were used to investigate association between dietary intake of B-vitamins and disease free survival. There was no association between dietary intake of B vitamins and breast cancer prognosis. However, we found higher dietary intake of vitamin B6 was associated with improved survival in patients with BMI more than 25kg/m2 (harzard ratio (HR), 0.32; 95% confidence intervals (CI), 0.11-0.94) or positive hormone status in estrogen receptor(ER)/progesterone receptor(PR) (HR, 0.39; 95%CI, 0.16-0.97). Our study suggests that the high intake of vitamin B6 is associated with improved breast cancer survival in patients with higher BMI and positive hormone status in ER/PR. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 641. doi:1538-7445.AM2012-641