Mitochondrial DNA 5178 C/A polymorphism influences the effects of habitual smoking on the risk of dyslipidemia in middle-aged Japanese men.

BACKGROUND: Several genetic polymorphisms have been reported to modify the effects of smoking on serum lipid levels. The objective of this study was to investigate whether longevity-associated mitochondrial DNA 5178 (Mt5178) C/A polymorphism modifies the effects of habitual smoking on the risk of dyslipidemia in middle-aged Japanese subjects. METHODS: A total of 394 male subjects (age, 53.9 ± 7.9 years; mean ± SD) were selected from among individuals visiting the hospital for regular medical check-ups. After Mt5178 C/A genotyping, a cross-sectional study assessing the joint effect of Mt5178 C/A polymorphism and cigarette smoking on the risk of hypo-high-density lipoprotein (HDL) cholesterolemia, hyper-low-density lipoprotein (LDL) cholesterolemia or hypertriglyceridemia was conducted. RESULTS: For subjects with Mt5178C, the risk of hypo-HDL cholesterolemia increased with the number of cigarettes smoked daily (P for trend = 0.001). On the other hand, the association between Mt5178A genotype and the risk of hypo-HDL cholesterolemia did not appear to depend on the number of cigarettes smoked daily. For those with Mt5178A, the risk of hyper-LDL cholesterolemia or hypertriglyceridemia increased with cigarettes smoked daily (P for trend = 0.017 and P for trend = 0.002, respectively). However, the association between Mt5178C genotype and the risk of hyper-LDL cholesterolemia or hypertriglyceridemia did not depend on the number of cigarettes smoked daily. CONCLUSIONS: The present results suggest that Mt5178 C/A polymorphism modulates the effects of habitual smoking on the risk of dyslipidemia in middle-aged Japanese men.

Eating behavior and childhood overweight among population-based elementary schoolchildren in Japan.

This study investigated the relationship between eating behavior and childhood overweight among population-based elementary schoolchildren in Japan. Data was collected from fourth graders (9 or 10 years of age) from Ina Town, Saitama Prefecture, Japan from 1999 to 2009. Information about subjects' sex, age, and lifestyle, including eating behaviors (eating until full and chewing thoroughly), was obtained using a self-administered questionnaire, and height and weight were measured directly. Overweight was determined according to the definition established by the International Obesity Task Force. Data from 4027 subjects (2079 boys and 1948 girls) were analyzed. Chewing thoroughly was associated with a significantly decreased odds ratio (OR) for being overweight, whereas eating until full significantly increased the OR for being overweight (OR: 1.50, 95% confidence interval: 1.16-1.94) among boys. However, eating until full was not associated with a significantly increased OR for being overweight among the group that reported chewing thoroughly, whereas it was associated with a significantly increased OR for being overweight (2.02, 1.38-2.94) among boys who did not chew thoroughly. In conclusion, eating until full or not chewing thoroughly was associated with being overweight among elementary schoolchildren. Results of this study suggest that chewing thoroughly may be an avenue to explore childhood overweight prevention efforts.

Blue Monday phenomenon among men: suicide deaths in Japan.

The number of suicide deaths in Japan has continued to be high, and is a pressing social problem. Although the weekly distribution of suicide deaths has been documented, no nationwide analysis has yet been conducted. In the present study, the ratios of the number of suicide deaths per day, by day of the week, and on weekdays relative to holidays were calculated using the data for all suicide deaths recorded in 2003. The suicide deaths recorded on holidays were treated as the reference, and a confidence interval of 95% (95% CI) was used. We calculated the suicide death ratios among men and women of all ages (men:23,396, women:8,713, total:32,109) and also among those of productive age (age:15-64 years, men:18,552, women:5,481, total:24,033). Among men of all ages, the suicide death ratio on Mondays was found to be significantly high at 1.49 (95% CI:1.04-2.14), and the ratios were found to decrease over the course of the week from Monday to Friday. On each weekday, the suicide death ratios among men of productive age were found to be higher than those among men of all ages. Among women, the suicide death ratios on any weekday were found to be higher than 1, but there was no significant difference between the days. Among both men and women, the number of suicide deaths on holidays was lower than that on weekdays. This study revealed that the number of suicide deaths recorded per day on Mondays is 1.5 times higher than that on holidays among men. This suggests that the structure of the work week may possibly influence suicide deaths among men. Future discussions regarding the arrangement and distribution of weekly holidays should be conducted in order to reduce the number of suicide deaths.