Objectives.To evaluate the relationship among smoking, alcohol consumption, and obesity and benign or malignant parotid tumors in a Korean population.Methods.The Korean National Health Insurance Service-Health Screening Cohort (for ≥40-year-olds) was assessed from 2002 to 2013. In total, 336 benign parotid tumors and 46 malignant parotid tumors were matched with controls at a ratio of 1 to 4 with respect to age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia. We analyzed previous histories of smoking, alcohol consumption, and obesity. By unconditional logistic regression analyses, the crude and adjusted odds ratios (ORs) were investigated and the 95% confidence intervals (CIs) were counted.Results.The estimated annual incidence of the benign parotid tumors was 5.66 per 100,000, and that of the malignant parotid tumor was 0.81 per 100,000. The adjusted ORs of smoking for the benign parotid tumors was 2.52 (95% CI, 1.84 to 3.46). This finding was consistent in the subgroups of <60 years old, ≥60 years old, and men. The adjusted ORs of alcohol consumption for the benign parotid tumors showed the statistical significance only in women (adjusted OR, 2.35; 95% CI, 1.10 to 5.00). Obesity did not reach a statistical significance in any analysis.Conclusion.Benign parotid tumor was related with smoking, and it was linked with alcohol consumption in women only.

The aim of the present study was to assess the effects of skipping breakfast on diet quality and metabolic disease risk factors in healthy Korean adults. Subjects included 415 employees (118 men, 297 women; 30-50 years old) of Jaesang Hospital in Korea and their acquaintances. Data collected from each subject included anthropometric measurements, 3-day dietary intake, blood pressure, and blood analyses. The subjects were classified into three groups based on the number of days they skipped breakfast: 'Regular breakfast eater', 'Often breakfast eater', or 'Rare breakfast eater'. Participants in the 'Rare breakfast eater' group consumed less rice, potatoes, kimchi, vegetables, fish and shellfish, milk and dairy products, and sweets than did participants in the other two groups (P for trend < 0.05) and ate more cookies, cakes, and meat for dinner (P for trend < 0.05). Participants in the 'Rare breakfast eater' group consumed less daily energy, fat, dietary fiber, calcium, and potassium than did participants in the other groups (P for trend < 0.05). The percent energy from carbohydrates was lower and fat intake was higher in the 'Rare breakfast eater' group than in the other groups (P for trend < 0.01). When diets were compared using the Acceptable Macronutrient Distribution Range for Koreans, 59.1% of subjects in the 'Rare breakfast eater' group consumed more energy from fat compared with the other two groups (P < 0.005). According to the Estimated Average Requirements for Koreans, intake of selected nutrients was lower in the 'Rare breakfast eater' group than in the other two groups (P < 0.05). The risk of elevated serum triglycerides was decreased in the 'Rare breakfast eater' group (OR, 0.3 [0.1-1.0], P for trend = 0.0232). We conclude that eating breakfast regularly enhances diet quality, but may increase the risk of elevated serum triglycerides.

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The objective of this study is to develop a method of controlling vortex shedding behind a bluff body using control theory. A suboptimal feedback control procedure for local sensing and local actuation is developed and applied to the flow behind a circular cylinder. The location of sensors for feedback is limited to the cylinder surface and the control input from actuators is the blowing and suction on the cylinder surface. Three different cost functionals to be minimized (J1 and J2) or maximized (J3) are investigated: J1 is proportional to the pressure drag of the cylinder, J2 is the square of the difference between the target pressure (inviscid flow pressure) and real flow pressure on the cylinder surface, and J3 is the square of the pressure gradient on the cylinder surface, respectively. Given the cost functionals, the flow variable to be measured by the sensors and the control input from the actuators are determined from the suboptimal feedback control procedure. Several cases for each cost functional have been numerically simulated at Re = 100 and 160 to investigate the performance of the control algorithm. For all actuations, vortex shedding becomes weak or disappears, and the mean drag and drag/lift fluctuations significantly decrease. For a given magnitude of the blowing/suction, reducing J2 provides the largest drag reduction among the three cost functionals.

Objective To investigate the bidirectional relation between RA and depression. Methods Data from the Korean Health Insurance Review and Assessment Service – National Sample Cohort from 2002 to 2013 were analysed. Patients ≥20 years of age were included. Study I was conducted with 38 087 depression patients and 152 348 matched control participants. Study II was conducted with 7385 RA patients and 29 540 matched control participants. Stratified Cox proportional hazards models were used to analyse the hazard ratios (HRs) for depression and RA (study I) and for RA and depression (study II). The data were adjusted by the Charlson comorbidity index; rheumatic disease was excluded. Subgroups were also analysed according to age and sex. Results A total of 0.7% (1260/38 087) of the depression group and 0.6% (883/152 348) of the control I group had RA (P = 0.02). The HR for RA in the depression group was not significantly higher than that in control I group. In study II, 5.5% (408/7385) of the RA group and 4.3% (1246/29 540) of the control II group presented with depression (P < 0.001). The RA patients showed an adjusted depression HR that was 1.20 times higher (95% CI 1.07, 1.34; P = 0.002) than that of the control group. The >30-years-old and women subgroups of RA patients showed higher depression HRs than the control subgroups. Conclusion RA increased the risk of depression; however, depression did not increase the risk of RA in the Korean adult population.

ObjectiveThis study examined the relationship between sleep duration, sleep quality and food consumption among adolescents.DesignCross-sectional study.SettingData from the 2014 and 2015 Korea Youth Risk Behavior Web-based Survey were used.ParticipantsParticipants aged 12–18 years (n=118 462 (59 431 males and 59 031 females)) were selected.Primary and secondary outcome measuresSleep duration, sleep quality and the frequencies of fruits, soda, soft drinks, fast food, instant noodle, confectionaries, vegetables and milk consumption.ResultsShort sleep durations (<6 hours) were associated with higher soft drinks and confectionaries intake than longer sleep durations (9+ hours) (adjusted ORs (AORs) (95% CIs) for ≥5 times a week for soft drinks: 1.73 (1.57 to 1.91) and confectionaries: 1.32 (1.20 to 1.46); p<0.001). Poor sleep quality, with 7–8 hours of sleep, was associated with a lower intake of fruits, vegetables and milk (AORs (95% CIs) for ≥5 times a week for fruits: 0.71 (0.65 to 0.77); vegetables: 0.66 (0.58 to 0.75); and milk: 0.80 (0.74 to 0.86); each p<0.001), and higher intake of soda, soft drinks, fast food, instant noodle and confectionaries (AORs (95% CIs) for ≥5 times a week for soda: 1.55 (1.40 to 1.70); soft drinks: 1.58 (1.43 to 1.73); fast food: 1.97 (1.65 to 2.35); instant noodle: 1.55 (1.37 to 1.76); and confectionaries: 1.30 (1.18 to 1.43); each p<0.001) than good sleep quality of the same duration.ConclusionShort sleep durations and poor sleep quality might be associated with higher consumption of unhealthier foods, such as sugar-sweetened beverages, fast food, instant noodle and confectionaries, and associated with lower consumption of fruits, vegetables and milk.

This study aimed to evaluate the impact of weather conditions and air pollution on the onset of sudden sensorineural hearing loss (SSNHL). The Korean Health Insurance Review and Assessment Service - National Sample Cohort (HIRA-NSC) from 2002 through 2013 was used. A total of 5,200 participants with SSNHL were matched 1:4 for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia with 20,800 control participants. Meteorological data included daily mean temperature (°C), daily highest temperature (°C), daily lowest temperature (°C), daily temperature difference (°C), relative humidity (%), ambient atmospheric pressure (hPa), pressure, SO 2 (ppm), NO 2 (ppm), O 3 (ppm), CO (ppm), and PM 10 (μg/m 3 ) of a mean of 60 days, 30 days, 14 days, 7 days, and 3 days before SSNHL were analyzed. Hourly measurements were taken from 94 places to assess the temperature, humidity, and atmospheric pressure and from 273 places to determine SO 2 , NO 2 , O 3 , CO, and PM 10 . Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of meteorological data for SSNHL were analyzed using unconditional logistic regression analyses. Subgroup analyses were conducted by age and sex. The mean NO 2 and O 3 concentrations 14 days before the index date were different in the SSNHL group compared to those in the control group (P < 0.001 for NO 2 and P = 0.021 for O 3 ). The adjusted 14-day OR for NO 2 (0.1 ppm) exposure was 3.12 in the SSNHL group compared to that in the control group (95% CI = 2.16–4.49, P < 0.001). The increased odds of NO 2 exposure for 14 days in the SSNHL group persisted in the age group older than 30 years for both sexes. Other meteorological conditions did not show differences between the SSNHL and control groups. SSNHL was associated with high concentrations of NO 2.

Objective. We evaluated the change in income level in a hearing-impaired population. Methods. The study subjects were selected from the Korean National Health Insurance Service-Health Screening Cohort data from 2002&#8211;2015 of Koreans