Association between misalignment of circadian rhythm and obesity in Korean men: Sixth Korea National Health and Nutrition Examination Survey.

Background: The disruption of circadian rhythm has been found to associate with obesity in vivo and in vitro. Sleep duration, eating habits, total feeding time, and nightshift work can also affect circadian rhythms. This study investigated the association between misalignment of circadian rhythm and obesity in Korean men, using a cross-sectional database.Methods: This study used data from the Korean National Health and Nutrition Examination Survey (KNHANES), whose study population was 3,658 men aged 18 to 60 years. General and abdominal obesity was defined as a body mass index (BMI) ≥ 25 kg/m2 and waist circumference ≥ 90 cm, respectively. Circadian rhythm factors were determined with a self-report questionnaire and included breakfast frequency, sleep duration, and work time. Frequency of breakfast was divided into regular breakfast (five to seven times a week) and irregular breakfast (less than five times a week). Sleep duration was divided into less than 7 hours, 7-9 hours, and over 9 hours. Working time was defined as day/evening, night shift, and other type. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for general and abdominal obesity were calculated using multivariable logistic regression according to the number of factors that disturb the circadian rhythm.Results: Participants with 1 (aOR 1.34, 95% Cl 1.10-1.61) and ≥2 (aOR 1.62, 95% Cl 1.29-2.05) factors disturbing circadian rhythms were associated with elevated risk for general obesity. Similarly, those with 1 (aOR 1.33, 95% Cl 1.09-1.63) and ≥2 (aOR 1.70, 95% Cl 1.32-2.20) factors had elevated risk for abdominal obesity.Conclusions: Factors disturbing the circadian rhythm were associated with general and abdominal obesity. Additional studies are needed, and associations with metabolic diseases should be investigated.

Mean corpuscular volume levels and all-cause and liver cancer mortality.

BACKGROUND: An elevated mean corpuscular volume (MCV) is associated with aging, nutrition, alcohol abuse and more, and it is known as a survival predictor in chronically ill patients. The aim of this study was to investigate the association between MCV levels and mortality from all-causes, cancer and site-specific cancer in a non-anemic healthy population. METHODS: A total of 36,260 participants aged 40 years or older who underwent routine check-ups at Seoul National University Hospital Health Promotion Center between 1995 and 2008 were followed-up for mortality until December 31, 2008, retrospectively. RESULTS: During an average follow-up of 8.0 years, 1107 deaths including 547 cancer deaths were observed. The adjusted hazard ratios (aHRs) of the subjects with the highest quartile of MCV ≥95.8 fL in men and MCV ≥94.2 fL in women for all-cause and cancer mortality were 1.44 [95% confidence interval (CI), 1.15-1.80] and 1.51 (95% CI, 1.10-2.07) for men and 1.55 (95% CI, 1.08-2.22) and 1.25 (95% CI, 0.74-2.11) for women, respectively, compared with those in the reference group (90.5 fL≤MC <93.0 fL in men and 89.2 fL≤MCV<91.6 fL in women). Elevated MCV level was related to an increased risk of liver cancer mortality in men (aHR, 3.55; 95% CI, 1.75-7.21). CONCLUSIONS: This study suggests that the elevated MCV level in non-anemic cancer-free individuals was associated with increased all-cause mortality in both men and women, and with cancer mortality, in particular liver cancer mortality in men. Future prospective studies are required to consolidate our findings.

Cancer Screening Adherence of Asian Women According to Biochemically-verified Smoking Status: Korea National Health and Nutrition Examination Survey.

BACKGROUND: Men and women who smoke tend to show less compliance to screening guidelines than non- smokers. However, a recent study in Korea showed that self-reported female smokers constituted less than half of cotinine-verified smokers. Therefore, the aim of this study was to identify hidden smokers using cotinine- verified method and examine cancer screening behavior according to biochemically verified smoking status. MATERIALS AND METHODS: Among 5,584 women aged 30 years and older who participated in the Fourth and Fifth Korea National Health and Nutrition Examination Survey (KNHANES), 372 (6.66%) hidden smokers were identified based on interview responses and verified by urinary cotinine levels. We compared cancer-screening behavior (cervical, breast, stomach, and colon cancer) of female hidden smokers to that of non-smokers and self- reported smokers by cross-sectional analysis. RESULTS: Hidden female smokers had significantly lower adherence to breast cancer screening compared to non-smokers (aOR (adjusted odds ratio) [95% CI] = 0.71 [0.51-0.98]). Adherence to stomach cancer (aOR [95% CI] = 0.75 [0.54-1.03]) and cervical cancer (aOR [95% CI] = 0.85 [0.66-1.10]) screening was also lower among hidden female smokers compared to non-smokers. Self-reported (current) smokers showed lowest adherence to cervical cancer (aOR: 0.64, 95% CI0.47-0.87), breast cancer (0.47 [0.32-0.68]), stomach cancer (0.66[0.46-0.95]), and colon cancer (0.62 [0.38-1.01]) screening compared to non-smokers, followed by female hidden smokers, then non-smokers. These lower adherence rates of current smokers were attenuated after we incorporated hidden smokers into the current smoker group. CONCLUSIONS: Cancer screening adherence of female hidden smokers was lower than cotinine-verified non-smokers but higher than current smokers. Considering the risk of smoking-related cancer among women, identifying hidden smokers is important to encourage appropriate cancer screening.

Coffee consumption and bone mineral density in korean premenopausal women.

BACKGROUND: Although Asian people are known to have lower bone mass than that of Caucasians, little is known about coffee-associated bone health in Asian. This study aimed to assess the relationship between coffee consumption and bone mineral density (BMD) in Korean premenopausal women. METHODS: Data were obtained from the Fourth Korea National Health and Nutrition Examination Survey 2008-2009. The study population consisted of 1,761 Korean premenopausal women (mean age 36 years) who were measured for lumbar spine and femoral neck BMD and who completed a standardized questionnaire about coffee intake frequency. We excluded the participants who took hormone replacement therapy or medication for osteoporosis. The cross-sectional relationship between coffee consumption and impaired bone health (osteopenia or osteoporosis) was investigated by bone densitometry. RESULTS: Coffee consumption showed no significant association with BMD of either femoral neck or lumbar spine, independent of other factors. The adjusted odds ratios for BMD for those who consumed once in a day, twice a day and three times a day were 0.94 (0.70-1.26), 0.93 (0.67-1.28), and 1.02 (0.69-1.50), respectively (P for trend = 0.927). CONCLUSION: This study does not support the idea that coffee is a risk factor for impaired bone health in Korean premenopausal women.