Kihwan Jung

Association of Snoring With Chronic Bronchitis

BACKGROUND Snoring is more prevalent in patients with chronic bronchitis than in persons without it. Few studies have examined the effect of snoring on chronic bronchitis. We prospectively investigated the association between snoring and the incidence of chronic bronchitis. METHODS The baseline study was conducted from June 25, 2001, to January 29, 2003. Members of the study cohort consisted of 5015 male and female Korean citizens aged 40 to 69 years at baseline who participated in a comprehensive health examination and on-site interviews at Korea University Ansan Hospital. Of these, 4270 participants (52% men and 48% women) entered the analysis for the first 2-year follow-up from April 17, 2003, to February 20, 2005, and those who met the same inclusion criteria remained in the analysis for a second 2-year follow-up period from February 21, 2005, to November 17, 2006. We collected information on snoring at baseline and identified incident cases of chronic bronchitis during a 4-year follow-up period. On the baseline questionnaire, we excluded participants who reported the presence of cough and sputum production on most days for at least 3 months a year. RESULTS During 4 years of follow-up, we documented 314 cases of new-onset chronic bronchitis (27.1 cases per 1000 person-years). After taking into account age, smoking, and other risk factors for chronic bronchitis, the multivariate relative risks of chronic bronchitis were 1.25 (95% confidence interval [CI], 0.95-1.64) for persons snoring 5 times per week or less and 1.68 (95% CI, 1.17-2.42) for those snoring 6 to 7 times per week compared with never snorers (P for trend = .049). The analyses stratified by risk factors, including smoking, occupation, and body mass index, showed a stronger association among never smokers, house workers, and overweight persons. In analysis for the joint effect of smoking and snoring, the relative risks of chronic bronchitis were 1.39 (95% CI, 1.01-1.90) for nonsmoking and snoring, 2.31 (95% CI, 1.38-3.87) for smoking and never snoring, and 2.86 (95% CI, 1.91-4.27) for smoking and snoring compared with nonsmoking and never snoring. CONCLUSIONS This prospective study observed that snoring is associated with chronic bronchitis. Our findings provide support for the hypothesis that snoring influences the development of chronic bronchitis.

Prevalence of excessive daytime sleepiness and associated factors in the adult population of Korea

OBJECTIVE Information on the prevalence and correlates of excessive daytime sleepiness (EDS) is limited for Asians. We determined the prevalence of EDS and its associated factors in the adult population of Korea. SUBJECTS AND METHODS The subjects consisted of 4405 Koreans aged 40-69 years from the Korean Genome Epidemiology Study, which is an ongoing prospective population-based study. Data were collected from a comprehensive health examination and a questionnaire at baseline. RESULTS The prevalence of EDS was 12.2% (10.7% for men and 13.7% for women). In multivariate models including sociodemographic, biochemical, clinical and sleep-related factors, age, physical activity, education, habitual snoring, waking up feeling unrefreshed, perceived insufficient sleep, and crawly feelings in the legs were significantly associated with EDS. Subjects aged 50-59 years had an excess risk of EDS by 1.42-fold (95% confidence interval [CI]=1.13-1.77) compared to those aged 40-49 years. In addition, the subjects with top quartile group of physical activity had a 1.80-fold (95% CI=1.18-2.73) higher risk of EDS than those with the lowest quartile group. A higher level of education was inversely associated with the risk of EDS. Furthermore, the subjects with habitual snoring had a 1.92-fold (95% CI=1.47-2.50) greater risk of EDS than non-snorers. Perceived insufficient sleep also increased the risk of EDS by 1.58-fold (95% CI=1.29-1.93) compared to perceived sufficient sleep. Subjects with crawly feelings in the legs had a 1.51-fold (95% CI=1.13-2.00) higher risk of EDS than those without crawly feelings in the legs. In addition, waking up feeling unrefreshed elevated a 1.24-fold (95% CI=1.01-1.53) risk of EDS compared to waking up feeling refreshed. CONCLUSIONS Our findings show that EDS is associated with a variety of factors in Korean adults, and habitual snoring or sleep-related problems increase the risk of EDS. Whether interventions to modify associated correlates can alter EDS warrants further study.

Immune regulatory effects of simvastatin on regulatory T cell-mediated tumour immune tolerance

Statins are potent inhibitors of hydroxyl‐3‐methylglutaryl co‐enzyme A (HMG‐CoA) reductase, and have emerged as potential anti‐cancer agents based on preclinical evidence. In particular, compelling evidence suggests that statins have a wide range of immunomodulatory properties. However, little is known about the role of statins in tumour immune tolerance. Tumour immune tolerance involves the production of immunosuppressive molecules, such as interleukin (IL)‐10, transforming growth factor (TGF)‐β and indoleamine‐2,3‐dioxygenase (IDO) by tumours, which induce a regulatory T cell (Treg) response. In this study, we investigated the effect of simvastatin on the production of IL‐10, TGF‐β and IDO production and the proliferation of Tregs using several cancer cell lines, and Lewis lung cancer (3LL) cells‐inoculated mouse tumour model. Simvastatin treatment resulted in a decrease in the number of cancer cells (3LL, A549 and NCI‐H292). The production of the immune regulatory markers IL‐10, TGF‐β in 3LL and NCI‐H292 cells increased after treatment with simvastatin. The expression of IDO and forkhead box P3 (FoxP3) transcription factor was also increased in the presence of simvastatin. In a murine 3LL model, there were no significant differences in tumour growth rate between untreated and simvastatin‐treated mice groups. Therefore, while simvastatin had an anti‐proliferative effect, it also exhibited immune tolerance‐promoting properties during tumour development. Thus, due to these opposing actions, simvastatin had no net effect on tumour growth.

CysA2: A candidate serodiagnostic marker for Mycobacterium tuberculosis infection

Background and objective:  It is important to identify and test serologically active antigens in order to devise a mixture of antigens or peptides that is most useful for serodiagnosis. This study evaluated the serodiagnostic potential of CysA2, which has not previously been described as a serological antigen, together with those of PstS1, HspX, antigen 85 complex and CFP‐10 proteins.