Assessment of Cardiac Autonomic Function in Relation to Methylmercury Neurotoxicity

After the European Food Safety Authority reviewed reports of methylmercury and heart rate variability (HRV) in 2012, the panel concluded that, although some studies of cardiac autonomy suggested an autonomic effect of methylmercury, the results were inconsistent among studies and the implications for health were unclear. In this study, we reconsider this association by adding a perspective on the physiological context. Cardiovascular rhythmicity is usually studied within different frequency domains of HRV. Three spectral components are usually detected; in humans these are centered at <0.04 Hz, 0.15 Hz (LF), and 0.3 Hz (HF). LF and HF (sympathetic and parasympathetic activities, respectively) are evaluated in terms of frequency and power. By searching PubMed, we identified 13 studies examining the effect of methylmercury exposure on HRV in human populations in the Faroe Islands, the Seychelles and other countries. Considering both reduced HRV and sympathodominant state (i.e., lower HF, higher LF, or higher LF/HF ratio) as autonomic abnormality, eight of them showed the significant association with methylmercury exposure. Five studies failed to demonstrate any significant association. In conclusion, these data suggest that increased methylmercury exposure was consistently associated with autonomic abnormality, though the influence of methylmercury on HRV (e.g., LF) might differ for prenatal and postnatal exposures. The results with HRV should be included in the risk characterization of methylmercury. The HRV parameters calculated by frequency domain analysis appear to be more sensitive to methylmercury exposure than those by time domain analysis

Cross-sectional survey of depressive symptoms and suicide-related ideation at a Japanese national university during the COVID-19 stay-home order

Background We aimed to estimate the prevalence of depressive symptoms as well as suicide-related ideation among Japanese university students during the stay-home order necessitated by the coronavirus disease 2019 pandemic in Japan, and offer evidence in support of future intervention to depression and suicide prevention strategies among college and university students. Methods The data for this cross-sectional study were derived from the Student Mental Health Survey conducted from May 20 to June 16, 2020 at a national university in Akita prefecture. Among the 5111 students recruited, 2712 participated in this study (response rate, 53%; mean age ± standard deviation, 20.5 ±3.5 years; men, 53.8%). Depressive symptoms were identified by using the Patient Health Questionnaire-9 (PHQ-9). Results The prevalence of moderate depressive symptoms based on a PHQ-9 score ≥10 and suicide-related ideation based on question 9 of PHQ-9 ≥1, which encompasses thoughts of both suicide and self-harm, was 11.7% and 6.7%, respectively. Multivariable logistic regression analyses showed that risk factors for depression included being a woman, smoking, alcohol consumption, and social network communication using either video or voice. For suicide-related ideation, alcohol consumption was the only risk factor. Exercise and having someone to consult about worries were associated with decreased risk of both depressive symptoms and suicide-related ideation. Conclusions Negative lifestyles of smoking and drinking, and being a woman, may be important risk factors for depressive symptoms, whereas exercise and having someone to consult about worries may be protective factors

An Analysis of Factors Associated with Personal and Perceived Stigma Against Talking About Suicide in a Rural Japanese Community

A cross-sectional study was conducted to clarify what factors were associated with personal and perceived stigma against talking about suicide, considered as prejudicial attitudes, prior to a community-based intervention for suicide prevention. Among 1,442 residents aged 20 years and over who lived in a rural town in northern Japan and returned questionnaire forms containing complete information, 852 answered that they avoided talking about suicide (i.e., personal stigma) and 897 answered that they thought that people avoided talking about suicide (i.e., perceived stigma). The personal and perceived stigma was observed more frequently in females and those aged 40 years and over. The perceived stigma was significantly associated with both bereavement experiences from suicide of a family member and of a friend, belief that suicide is preventable (i.e., preventability), and suicidal ideation within one month. The personal stigma was significantly associated with bereavement experience from suicide of a friend and preventability. This is the first report to demonstrate stigma against talking about suicide at the community level. In addition, these data suggest that persons with perceived stigma against talking about suicide have stronger suicidal ideation than those with the personal stigma. A community-based education is needed to reduce such prejudicial attitudes toward suicide

QUANTITATIVE SIGNIFICANCE OF ETHANOL INTAKE, EATING PATTERNS, AND SLEEP DURATION AFFECTING LIPID PROFILES IN MIDDLE-AGED EMPLOYEES

A cross-sectional study was conducted to investigate the associations of ethanol intake, eating patterns, and sleep duration with serum triglycerides, LDL-cholesterol, and HDL-cholesterol levels, along with the contributions of these risk factors to lipids. Study participants (1,582 males and 424 females) who returned questionnaire forms and underwent the mandatory health checkup were enrolled. After adjusting for age, smoking, and exercise, the mean contribution ratio, representing the extent to which each independent variable explained lipid variations in a multiple regression analysis, in the males (and females) was 14% (9%) for body mass index, 2% (3%) for ethanol intake, 0.4% (1.3%) for a total of eating patterns, and 0.06% (0.06%) for sleep duration.　Ethanol intake was associated with high triglycerides, high HDL-cholesterol, and low LDL-cholesterol. Breakfast-skipping was associated with high LDL-cholesterol in the males, snacking during work hours was associated with low triglycerides in the females, and dinner time irregularity was associated with low triglycerides in the males. Long sleep duration was associated with high triglycerides in the males. However, there were not significant interactions between drinking and eating patterns in the males or females. In conclusion, preventive measures of dyslipidemia should be taken in consideration of the priority based on the quantitative significance of risk factors. Although moderate drinking appears to reduce risks of hyper-LDL and hypo-HDL cholesterolemia, it may lead to hypertriglyceridemia, in addition to hepatocellular injury and hypertension

Assessment of Cardiac Autonomic Function in Relation to Methylmercury Neurotoxicity

After the European Food Safety Authority reviewed reports of methylmercury and heart rate variability (HRV) in 2012, the panel concluded that, although some studies of cardiac autonomy suggested an autonomic effect of methylmercury, the results were inconsistent among studies and the implications for health were unclear. In this study, we reconsider this association by adding a perspective on the physiological context. Cardiovascular rhythmicity is usually studied within different frequency domains of HRV. Three spectral components are usually detected; in humans these are centered at &lt;0.04 Hz, 0.15 Hz (LF), and 0.3 Hz (HF). LF and HF (sympathetic and parasympathetic activities, respectively) are evaluated in terms of frequency and power. By searching PubMed, we identified 13 studies examining the effect of methylmercury exposure on HRV in human populations in the Faroe Islands, the Seychelles and other countries. Considering both reduced HRV and sympathodominant state (i.e., lower HF, higher LF, or higher LF/HF ratio) as autonomic abnormality, eight of them showed the significant association with methylmercury exposure. Five studies failed to demonstrate any significant association. In conclusion, these data suggest that increased methylmercury exposure was consistently associated with autonomic abnormality, though the influence of methylmercury on HRV (e.g., LF) might differ for prenatal and postnatal exposures. The results with HRV should be included in the risk characterization of methylmercury. The HRV parameters calculated by frequency domain analysis appear to be more sensitive to methylmercury exposure than those by time domain analysis

SUICIDE MORTALITY FOR YOUNG,MIDDLE-AGED AND ELDERLY PERSONS IN THE PERIOD OF JAPANESE ECONOMIC TRANSITION,1975-2005

In Japan, the number of suicide deaths per year has exceeded 30,000 after the bubble burst beginning in the 1990s. We explored suicide features, including the temporal and regional variations, in the period of economic transition, 1975-2005. The influences of social factors on the age-specific rates were also investigated to explain the features. Average age-specific rates with 10-year spans in each 5-year period and three social indicators in 47 prefectures were obtained from national data. Significant temporal and regional changes were observed in all age-specific suicide rates for men and women. Prefectural income per person was negatively correlated with the suicide rates for men aged 15-74 and for women aged 55-64, and outpatients in mental hospitals per day had positive correlations with the suicide rates for men aged 25 and over. Moreover, there were negative correlations between the proportion of persons employed in the tertiary industry and suicide rates for men aged 75 and over and for women aged 55 and over. In conclusion, all age-specific suicide rates for Japanese men and women changed drastically in the period of 1975-2005, but they showed regional clustering in 47 prefectures. A combination of social factors could explain the suicide rates for young and middle-aged men and for elderly people. Therefore, suicide prevention measures for different age-specific populations at risk in individual prefectures should be carefully taken