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.

High Exposure of Chinese Mercury Mine Workers to Elemental Mercury Vapor and Increased Methylmercury Levels in Their Hair

Objective: The aim of this study was to determine the level of exposure of mercury (Hg) miners and smelter workers to elemental mercury (Hg0) vapor in China, who work in Hg mines without using protective equipment against Hg0 vapor. In addition, the level of methylmercury (MeHg) intake by the workers was estimated from the MeHg concentration in their hair. Methods: Urinary total mercury (THg) and hair THg and MeHg concentrations were measured in 26 Hg miners and smelter workers (i.e., exposed group), and 48 unexposed people (unexposed group). Results: The exposed group showed high geometric mean THg concentrations in urine (258 ng/ml, 226 μg/g creatinine) and hair (20.0 μg/g). The urinary THg concentration of the smelter workers in particular was extremely high (338 μg/g creatinine in urine). The highest urine THg concentration reached 4577 μg/g creatinine. THg concentrations in urine and hair showed a significant correlation in the exposed group (r=0.62), indicating the adhesion of Hg0 vapor to hair. However, no such significant correlation was found in the unexposed group. Hair MeHg concentration in the exposed group (1.97 μg/g) was about threefold higher than that in the unexposed group (0.60 μg/g). Conclusions: This study shows that smelter workers in a Chinese Hg mine are exposed to extremely high levels of Hg0 vapor, and that Hg miners are exposed to higher levels of MeHg than the unexposed subjects. Further study is needed to determine the cause of the higher hair MeHg concentration in the exposed group.

Factors affecting hand tremor and postural sway in children

<p><b>OBJECTIVES</b>It is crucial to consider covariates relevant for outcome variables in developing dose-effect relations of environmental hazardous toxins. The aim of this study was to clarify the covariates affecting hand tremor and postural sway in children.</p><p><b>METHODS</b>Hand tremor and postural sway, as well as hair mercury concentrations, were measured in 155 boys and 148 girls at age 7 years.</p><p><b>RESULTS</b>Current mercury concentrations in child hair ranged from 0.35 to 6.32 μg/g (geometric mean, 1.71 μg/g for boys and 1.58 μg/g for girls), and were not significantly correlated with the neuromotor parameters. All hand tremor and postural sway parameters, except for tremor intensity at 1-6 Hz with non-dominant hand, were significantly larger in the boys than in the girls. Using multiple regression analysis, some postural sway parameters were related negatively to age in the boys and girls (p<0.05), and positively to height (p<0.05). Similarly, hand tremor parameters were positively related to age, height and heart rate either in the boys or in the girls (p<0.05). Also, there were positive relationships between tremor intensity at 1-6 Hz and transversal and sagittal sways at 1-2 Hz and 2-4 Hz (p<0.05).</p><p><b>CONCLUSIONS</b>Heart rate and postural sway, together with age, sex, and height, should be considered in interpreting hand tremor in children. Hand tremor or postural sway may not be so sensitive or specific to methylmercury exposures at levels of less than 7 μg/g in hair.</p>

Factors Affecting Hand Tremor and Postural Sway in Children

Objectives: It is crucial to consider covariates relevant for outcome variables in developing dose-effect relations of environmental hazardous toxins. The aim of this study was to clarify the covariates affecting hand tremor and postural sway in children. Methods: Hand tremor and postural sway, as well as hair mercury concentrations, were measured in 155 boys and 148 girls at age 7 years. Results: Current mercury concentrations in child hair ranged from 0.35 to 6.32 μg/g (geometric mean, 1.71 μg/g for boys and 1.58 μg/g for girls), and were not significantly correlated with the neuromotor parameters. All hand tremor and postural sway parameters, except for tremor intensity at 1–6 Hz with non-dominant hand, were significantly larger in the boys than in the girls. Using multiple regression analysis, some postural sway parameters were related negatively to age in the boys and girls (p<0.05), and positively to height (p<0.05). Similarly, hand tremor parameters were positively related to age, height and heart rate either in the boys or in the girls (p<0.05). Also, there were positive relationships between tremor intensity at 1–6 Hz and transversal and sagittal sways at 1–2 Hz and 2–4 Hz (p<0.05). Conclusions: Heart rate and postural sway, together with age, sex, and height, should be considered in interpreting hand tremor in children. Hand tremor or postural sway may not be so sensitive or specific to methylmercury exposures at levels of less than 7 μg/g in hair.

Effects of hair treatment on hair mercury-The best biomarker of methylmercury exposure?

<p><b>OBJECTIVES</b>Exposure misclassification is a major obstacle to obtain accurate dose-response relationships. In order to solve this problem, the impact of hair treatment on total mercury in hair was assessed in Japanese women.</p><p><b>METHODS</b>A cross-sectional study was carried out among 327 women at age 24-49 years to determine hair mercury levels and estimate daily mercury intakes from seafood by using a food frequency questionnaire.</p><p><b>RESULTS</b>Hair mercury levels in the women and daily mercury intake ranged from 0.11 to 6.86 (median 1.63) μg/g and from 0.77 to 144.9 (median 15.0) μg/day, respectively. The hair mercury was positively correlated with the daily mercury intake (p<0.001). When the women were divided into two subgroups based on artificial hair-waving, hair coloring/dyeing, residence (non-fishing and fishing areas), and working status, a significant difference in the hair mercury level was observed between the women with and without artificial hair-waving only (p<0.001). The multiple regression analysis showed that the log-transformed hair mercury level was significantly related to the log-transformed daily mercury intake (standardized regression coefficient βs=0.307) and artificial hair-waving (βs=-0.276); but not to hair coloring/dyeing, residence, working status or age. Permanent hair treatment was estimated to reduce total mercury in hair by approximately 30%, after adjusting for daily mercury intake and other possible factors.</p><p><b>CONCLUSIONS</b>These findings suggest that hair mercury is not the best biomarker of methylmercury exposure when a study population includes women with artificial hair-waving.</p>

Effects of Hair Treatment on Hair Mercury---The Best Biomarker of Methylmercury Exposure?

Objectives: Exposure misclassification is a major obstacle to obtain accurate dose-response relationships. In order to solve this problem, the impact of hair treatment on total mercury in hair was assessed in Japanese women. Methods: A cross-sectional study was carried out among 327 women at age 24-49 years to determine hair mercury levels and estimate daily mercury intakes from seafood by using a food frequency questionnaire. Results: Hair mercury levels in the women and daily mercury intake ranged from 0.11 to 6.86 (median 1.63) μg/g and from 0.77 to 144.9 (median 15.0) μg/day, respectively. The hair mercury was positively correlated with the daily mercury intake (p<0.001). When the women were divided into two subgroups based on artificial hair-waving, hair coloring/dyeing, residence (non-fishing and fishing areas), and working status, a significant difference in the hair mercury level was observed between the women with and without artificial hair-waving only (p<0.001). The multiple regression analysis showed that the log-transformed hair mercury level was significantly related to the log-transformed daily mercury intake (standardized regression coefficient βs=0.307) and artificial hair-waving (βs=−0.276); but not to hair coloring/dyeing, residence, working status or age. Permanent hair treatment was estimated to reduce total mercury in hair by approximately 30%, after adjusting for daily mercury intake and other possible factors. Conclusions: These findings suggest that hair mercury is not the best biomarker of methylmercury exposure when a study population includes women with artificial hair-waving.