Real Asymptomatic SARS-CoV-2 Infection Might Be Rare: Importance of Careful Interviews and Follow-up.

BACKGROUND: There is limited information on the clinical characteristics of patients with coronavirus disease 2019 (COVID-19) who are asymptomatic or have mild symptoms. METHODS: We performed a retrospective case series of patients with COVID-19 enrolled from February 22 to March 26, 2020. Forty cases of COVID-19 were confirmed using real-time reverse-transcription polymerase chain reaction among patients who underwent screening tests and were consecutively hospitalized at Ulsan University Hospital, Ulsan, Korea. The final follow-up date was May 19, 2020. All COVID-19 cases in Ulsan were included. Demographic and epidemiological information, comorbidities, clinical signs and symptoms, laboratory and radiologic findings, medications, treatments, outcomes, and main durations of patients with COVID-19 were compared according to supplemental oxygen requirement. RESULTS: Forty patients were included (median age, 30 years; interquartile range [IQR], 25-57 years; 58% female). Six (15%) patients required supplemental oxygen. The prevalence of asymptomatic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection was 5% and that of presymptomatic infection was 13%. Cough, fever, myalgia, rhinorrhea or nasal congestion, and diarrhea were the screening criteria for diagnosing symptomatic and presymptomatic SARS-CoV-2 infections. Sputum production, chest discomfort, a large number of symptoms, abnormal procalcitonin and C-reactive protein levels, and abnormal chest X-ray or chest computed tomography findings were more common in patients requiring supplemental oxygen than in those not requiring supplemental oxygen. Overall mortality rate was 3% (1/40). Four patients (10%) were readmitted after testing positive by reverse-transcription polymerase chain reaction again. Incubation period was 5 days (IQR, 4-6 days), and the duration of viral shedding was 21 days (IQR, 14-28 days; maximum, 51 days). CONCLUSION: The prevalence of asymptomatic SARS-CoV-2 infection was 5%, which is much lower than that previously reported. This finding suggests that careful interviews and follow-ups should be performed to identify SARS-CoV-2 infections. Cough, fever, myalgia, rhinorrhea or nasal congestion, and diarrhea are adequate screening criteria for covering all symptoms of SARS-CoV-2 infection. Further evaluation is required to create representative screening criteria for COVID-19.

Relationship of serum gamma-glutamyltransferase levels with pulmonary function and chronic obstructive pulmonary disease.

BACKGROUND: Gamma-glutamyltransferase (GGT) levels within the normal reference range, possibly a biomarker of oxidative stress and/or exposure to various environmental chemicals, are associated with pulmonary function. However, it is unclear whether it is totally independent of cigarette smoking. Also, the potential interaction between serum GGT and cigarette smoking has not ever been evaluated. Therefore, this study investigated (1) whether serum GGT levels are associated with pulmonary function and chronic obstructive pulmonary disease (COPD), independent of cigarette smoking, and (2) whether there is any interaction between serum GGT and cigarette smoking status on pulmonary function. METHODS: The study subjects were 4,583 participants aged ≥ 40 in the 2010-2011 Korean National Health and Nutrition Examination Survey. The outcomes were pulmonary function (forced expiratory volume in 1 second [FEV1] and forced vital capacity [FVC]) and spirometrically defined COPD. RESULTS: After adjusting for potential confounders, including cigarette smoking, serum GGT levels were inversely associated with FEV1 and FVC in both genders and positively associated with the risk of COPD in men (all P values < 0.01). In men, adjusted odds ratios of COPD were 1.0, 1.69, 1.97, and 2.02 across the quartiles of GGT level (P trend = 0.002). However, the associations between serum GGT and pulmonary function seemed to differ depending on the smoking status; inverse associations of GGT with FEV1 % and FVC % were clearly observed only among non-current smokers. CONCLUSIONS: In conclusion, in non-smokers serum GGT levels can be used to detect individuals at high risk of decreased pulmonary function and/or COPD.

Changes in the Serum Level of High Density Lipoprotein-cholesterol after Smoking Cessation among Adult Men.

BACKGROUND: Smoking and obesity are known risk factors for cardiovascular diseases, while low serum levels of high density lipoprotein-cholesterol is an independent risk factor for mortality from ischemic heart diseases. This study examines changes in the serum level of high density lipoprotein-cholesterol depending on changes in the state of smoking and body mass index. METHODS: A survey and blood check-up were conducted on medical examination, along with acts of smoking among male adults of 25 years or older who visited the health promotion center of Daegu Medical Center from 2007 to 2010, and the results were analyzed. The subjects were divided into two different groups, current smokers and abstainers, and body mass index, total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, and triglycerides for three years were compared in both groups. Changes between the first and second visits in body mass index and lipid profiles of the two groups were compared to analyze changes after abstaining. RESULTS: The subject group which showed a significant increase in high density lipoprotein-cholesterol level was only abstainers whose body mass index had decreased by more than 0.5 kg/m(2). CONCLUSION: Smoking cessation increases serum levels of high density lipoprotein-cholesterol. If reduction of body mass index and smoking cessation are combined, the risk of cardiovascular disease will be lower in proportion to the increase in serum high density lipoprotein.