Effect of renal tubular damage on non-cancer mortality in the general Japanese population living in cadmium non-polluted areas.

This study aimed to clarify the cause-effect relationship between renal tubular damage and non-cancer mortality in the general Japanese population. We conducted a 19-year cohort study including 1110 men and 1,03 women who lived in three cadmium-non-polluted areas in 1993 or 1994. Mortality risk ratios based on urinary ß2-microglobulin (ß2MG) and N-acetyl-ß-glucosaminidase (NAG) concentrations were estimated for specific non-cancer diseases using the Fine and Gray competing risks regression model. In men, continuous urinary NAG (+1 µg/g cre) concentrations were significantly correlated with increased mortality caused by diseases of the respiratory system (hazard ratio (HR): 1.09, 95% confidence interval (CI): 1.03-1.15). Urinary ß2MG (+100 µg/g cre) concentrations were significantly correlated with increased mortalities caused by kidney and urinary tract diseases (HR: 1.01, 95% CI: 1.00-1.03), renal diseases (HR: 1.01, 95% CI: 1.00-1.03), renal failure (HR: 1.02, 95% CI: 1.00-1.03), and external causes of mortality (HR: 1.01, 95% CI: 1.00-1.02). In women, urinary NAG (+1 µg/g cre) concentrations were significantly associated with increased mortality caused by ischemic heart diseases (HR: 1.02, 95% CI: 1.00-1.04) and kidney and urinary tract diseases (HR: 1.01, 95% CI: 1.00-1.04). Urinary ß2MG (+100 µg/g cre) concentrations were significantly correlated with increased mortality caused by cardiovascular diseases (HR: 1.01, 95%CI: 1.00-1.02), ischemic heart diseases (HR: 1.01, 95%CI: 1.00-1.02), and kidney and urinary tract diseases (HR: 1.02, 95% CI: 1.01-1.03). The present study indicates that renal tubular damage was significantly related to several non-cancer disease causes of mortality in Japan's general population living in cadmium-non-polluted areas.

Cadmium body burden and health effects after restoration of cadmium-polluted soils in cadmium-polluted areas in the Jinzu River basin.

BACKGROUND: Itai-itai disease is caused by environmental cadmium (Cd) pollution in the Jinzu River basin in Japan. To reduce the Cd contamination of rice, soil restoration of paddy fields was carried out. We evaluated the effect of soil restoration on the health status of residents of the former Cd-polluted area. METHODS: Participants were 1,030 men and 944 women who lived in the area of restoration of Cd-polluted rice paddies. First morning urine was collected and urinary Cd, ß2-microglobulin (ß2MG), and N-acetyl-ß-D-glucosaminidase (NAG) levels were measured. Associations among age, years of residence before and after soil restoration, and urinary Cd, ß2MG, and NAG levels were evaluated by multiple regression analysis. RESULTS: The geometric mean (interquartile range) of urinary Cd (µg/g Cr) was 1.00 (0.58-1.68) in men and 1.67 (1.02-2.91) in women. The geometric means of urinary ß2MG (µg/g Cr) and NAG (U/g Cr) were 174.6 (92.6-234.2) and 1.47 (0.72-3.14) in men, and 217.6 (115.3-28.7) and 1.48 (0.73-2.96) in women, respectively. Urinary Cd, ß2MG, and NAG were significantly positively correlated (p < 0.01 all). Age and duration of residence in the Cd-polluted area before soil restoration were independently associated with urinary Cd, ß2MG, and NAG. Among the 916 participants who had resided in the area before the soil restoration, urinary Cd concentrations were significantly higher, thus by 1.03-fold (95% CI, 1.01-1.04) in men and 1.03-fold (95% CI, 1.01-1.05) in women, when the years of residence before soil restoration by each 5-years increment. By contrast, urinary Cd concentrations were significantly lower, thus 0.97-fold (95% CI, 0.96-0.99) lower in men and 0.97-fold (95% CI, 0.95-0.99) lower in women, by each 5-year increment of residence after soil restoration. A similar association was observed for urinary ß2MG concentration, and no significant association was observed for urinary NAG levels in men or women. CONCLUSIONS: Cd exposure and associated renal tubular dysfunction in residents of a former Cd-polluted area were influenced by Cd exposure from the environment prior to soil restoration. Soil restoration in Cd-polluted areas reduced the Cd exposure of local residents.

Renal tubular dysfunction and cancer mortality in the Japanese general population living in cadmium-non-contaminated areas.

The relationship between cadmium exposure, exposure-related renal tubular dysfunction, and mortality have been reported, mainly in the residents of Cd-contaminated areas in Japan. The aim of this study was to establish the cause-effect relationship between renal tubular dysfunction and cancer mortality in the general population in non-contaminated areas. A 19-year cohort study was conducted in 1110 men and 1703 women in 1993 or 1994, who lived in three cadmium-non-contaminated areas. Mortality risk ratios of urinary ß2-microglobulin (ß2MG) and N-acetyl-ß-glucosaminidase (NAG) for all malignant neoplasms and specific cancers were estimated using the Fine and Gray competing risks regression model. Significant hazard ratios (HRs) for liver and pancreas cancer were observed for NAG (liver: HR corresponding to an increase of 1 IU/g cr, 1.10, 95%CI, 1.02-1.19, pancreas: HR, 1.10, 95%CI, 1.02-1.19) in men. In women, a negative HR was observed for NAG (lung cancer: HR 0.80, 95% CI, 0.67-0.96) and for ß2MG (all malignant neoplasms: HR, 0.97, 95% CI, 0.93-1.00). The present study indicated that renal tubular dysfunction was significantly related to mortality in the general population of cadmium-non-contaminated areas in Japan.

Environmental cadmium exposure and noncancer mortality in a general Japanese population in cadmium nonpolluted regions.

The objective of this study was to assess the effect of environmental cadmium exposure according to urinary cadmium concentration (U-Cd) on noncancer mortality in a general Japanese population. We conducted a longitudinal study for 19 years in 2804 inhabitants (1107 men and 1697 women) in some cadmium nonpolluted regions in Japan. The participants were classified into quartiles based on U-Cd (µg/g cre) adjusted for urinary creatinine. Hazard ratio (HR) and 95% confidence interval (95% CI) for continuous U-Cd or the quartiles of U-Cd were calculated for noncancer mortality. By applying a Fine and Gray competing risk model, continuous U-Cd (+1 µg/g cre) showed significant HR for cardiocerebrovascular diseases (HR 1.05, 95% CI: 1.00-1.11), cerebrovascular diseases (HR 1.08, 95% CI: 1.01-1.16), and cerebral infarction (HR 1.11, 95% CI: 1.04-1.20) in men. However, notable significant HR for continuous and quartered U-Cd were not observed in women. In this study, U-Cd was associated with increased cardiocerebrovascular mortality in a general Japanese population, suggesting that environmental cadmium exposure is detrimental to the life prognosis in cadmium nonpolluted regions in Japan.

Relationship between urinary ß2 -microglobulin concentration and mortality in a cadmium-polluted area in Japan: A 35-year follow-up study.

The relationship between urinary ß2 -microglobulin (ß2 -MG) and the risk of all-cause mortality and cause-specific mortality in a cadmium (Cd)-polluted area was investigated in 3139 inhabitants (1404 men and 1735 women) of the Kakehashi River basin in Japan at 35-year follow-up. The subjects had been participants in the 1981-1982 health impact survey that assessed Cd-induced renal dysfunction, as measured by the urinary ß2 -MG concentration. Hazard ratios were calculated to assess the risk of all-cause and cause-specific mortality according to the urinary ß2 -MG concentrations. Risk ratios (RRs) were assessed using the Fine and Gray regression model to account for competing risks of cause-specific mortality. The mortality rate was significantly higher in participants with urinary ß2 -MG concentrations >1000 µg/g creatinine (Cr) for men and >300 µg/g Cr for women. In the proportional hazard model, higher urinary ß2 -MG concentrations were associated with higher risks of circulatory disease, digestive system diseases, and kidney and urinary tract diseases in men and women, and with senility for women. However, when competing risk was accounted for, the RRs were significantly higher only for kidney and urinary tract diseases in men and women (RR for each increment of 1000 µg/g Cr [95% confidence interval]: 1.02 [1.00-1.04] for men, and 1.01 [1.00-1.02] for women). The long-term prognosis of participants with renal tubular dysfunction was poor, most likely due to kidney and renal tract diseases.

Increase of lifetime cadmium intake dose-dependently increased all cause of mortality in female inhabitants of the cadmium-polluted Jinzu River basin, Toyama, Japan.

BACKGROUND: Exposure to cadmium (Cd) via food is supposed to affect life prognosis of inhabitants of Cd-polluted area in Japan. However, there have been few reports demonstrating a significant relationship between the amount of Cd intake and mortality. We aimed to investigate the relationship between mortality and individual lifetime Cd intake (LCd) in inhabitants of the polluted Jinzu River basin, Toyama, Japan. METHODS: We conducted a 26-year follow-up survey in 2407 inhabitants (1208 men and 1199 women) who participated in health examinations for screening of renal dysfunction from 1979 to 1984. The calculation of LCd in each inhabitant was based on the formula of Nogawa (Nogawa et al., 1989): (mean Cd concentration in rice of the present hamlet × 333.5 g/day + 34 µg/day) × 365 days/year × number of years of residence in the present hamlet + 50 µg/day × 365 days/year × number of years living in Cd non-polluted regions. In this formula, 333.5 g/day is the 1970 average daily intake of rice in this area, 34 µg/day is the Cd intake from foods other than rice in this area, and 50 µg/day is the average intake of Cd in non-polluted areas in Japan. Mortality risk ratios of LCd for all and specific causes were estimated after adjustments for age at baseline, smoking status, and history of hypertension using a Cox hazard model or Fine and Gray competing risks regression model. RESULTS: The mortality risk ratios of LCd (+ 1 g) for all causes in women were significantly dose-dependently increased (risk ratio: 1.08). Relative risk of LCd for kidney and urinal tract disease, renal diseases, renal failure and toxic effects of cadmium were significantly higher in women. CONCLUSIONS: The present study documents that individual LCd dose-dependently decreased life prognosis over long-term observation in women. LCd was significantly related to the increased mortality for renal disease and toxic effect of Cd in women. The result provides clear evidence that life prognosis was adversely affected by Cd-exposure, especially in women.

Relationship between mortality and rice cadmium concentration in inhabitants of the polluted Jinzu River basin, Toyama, Japan: A 26 year follow-up.

The aim of this study was to investigate the relationship between mortality and rice cadmium (Cd) concentration in inhabitants of a polluted area in Japan. The target subjects were inhabitants of the Jinzu River basin who participated in health examinations for screening of renal dysfunction from 1979 to 1984. The mean rice Cd concentration in each hamlet was used as an index of the Cd exposure. We conducted a 26 year follow-up survey in 3281 inhabitants (1544 men and 1737 women) whose data regarding the rice Cd concentration were available. Mortality risk ratios for all and specific causes were estimated after adjustments for age at baseline, smoking status and history of hypertension using a Cox hazard model or Fine and Gray competing risks regression model. The mortality risk ratios of rice Cd concentration (+0.1 ppm) for all causes in women were significantly increased (risk ratio: 1.04). Furthermore, the relative risks of rice Cd concentration for kidney and urinary tract disease, renal diseases, renal failure and toxic effects of cadmium were significantly increased in both sexes. These findings indicated that increased rice Cd concentration decreased the prognosis for life over a long-term observation in women. This result provides important information for determining the worldwide standard for allowable rice Cd concentration.

Threshold limit values of the cadmium concentration in rice in the development of itai-itai disease using benchmark dose analysis.

The aim of this study was to estimate the benchmark dose (BMD) as the threshold limit level of the cadmium (Cd) concentration in rice for itai-itai disease and/or suspected disease; it was based on the data that previously evaluated the association for such diseases with the Cd concentration in rice by using a logistic regression model. From 1971 to 1976, a total of 2446 rice samples were analyzed across the 88 hamlets in the Jinzu river basin. The mean Cd concentration in rice in each hamlet was used as the index of external Cd exposure of the entire population of the hamlet. We employed the incidence of itai-itai disease and/or suspected disease obtained from the available 55 hamlets. As the threshold, the lower limit of the BMD (BMDL) of the Cd concentration in rice for itai-itai disease and/or suspected disease was estimated using a logistic model, setting the benchmark response at 1% or 2%. The estimated BMDLs of the Cd concentration in rice for itai-itai disease and/or suspected disease were 0.62-0.76 and 0.27-0.56 mg kg-1 in men and women, respectively. The lowest BMDL was 0.27 mg kg-1 in women. In the present study, the threshold limit level of the Cd concentration in rice for itai-itai disease, which is the most severe form of chronic Cd poisoning, was estimated for the first time. This result provides important information about the worldwide standard for the Cd concentration in rice. Copyright © 2017 John Wiley & Sons, Ltd.

Attenuation of Urinary Cadmium in Inhabitants of the Environmentally Exposed Jinzu River Basin Determined by Applying a Mixed Linear Model.

Half-life of urinary cadmium level (U-Cd) was estimated in inhabitants whose initial U-Cd was ≥5 µg/L (131 men and 177 women) or ≥5 µg/gcr (195 men and 246 women), using a linear mixed model adjusted for the baseline age. To clarify the effect of initial U-Cd, the target participants were divided into higher or lower initial U-Cd group. In the higher groups, the half-lives were 15.4 and 13.1 years for unadjusted U-Cd and 19.0 and 23.0 years for creatinine-adjusted U-Cd, in men and women, respectively. In the lower groups, the half-lives were 38.0 and 26.0 years for unadjusted U-Cd in men and women. For creatinine-adjusted U-Cd, it was 42.9 years in men. For attenuation of U-Cd, there were an early fast component shown in the higher group and late slow component shown in the lower group. The attenuation of U-Cd is slower in the longer time compared to that previously reported.

Different association of cigarette smoking with GFR estimated from serum creatinine and that from serum cystatin C in the general population.

BACKGROUND: Previous studies have shown that GFR estimated from serum creatinine (eGFRcr) is higher in smokers although the implications remain unclear. We aimed to clarify the associations of smoking with eGFRcys (GFR estimated from serum cystatin C) and eGFRcr, cys (the surmised most precise GFR estimate based on serum creatinine and cystatin C) in a working population. METHODS: Cross-sectional observation in 1,587 male workers aged 25-64 years. For eGFRcr, JEQcr proposed by the Japanese Society of Nephrology (JSN) and jEPIcr by the Chronic Kidney Disease Epidemiological Collaboration (CKD-EPI) modified for Japanese, and for eGFRcys, JEQcys proposed by JSN and EPIcys by CKD-EPI were calculated together with eGFRcr,cys of JEQaver (the average of JEQcr and JEQcys) and jEPIcr,cys by CKD-EPI modified for Japanese. RESULTS: Mean JEQcys was 95.1 mL/min/1.73 m(2) in contrast to 80.9 in JEQcr, with this difference considerable. Serum cystatin C was higher in smokers and obese subjects while serum creatinine was lower in smokers and slender subjects. JEQcys and EPIcys were lower in smokers while JEQcr and jEPIcr were higher in smokers adjusting for body mass index (BMI). eGFRcr,cys (JEQaver and jEPIcr,cys) did not differ between the never smokers and current smokers. eGFRcr,cys predicted by the equations composed of eGFRcr, BMI, and smoking habits showed a good accordance with calculated eGFRcr,cys. CONCLUSIONS: Either eGFRcr, eGFRcys or both were not reliable indicators of renal function in workers who smoked. The possibly more precise estimate of eGFRcr,cys could be predicted by eGFRcr, BMI and smoking in such a generally healthy population.

Overall sleep status and high sensitivity C-reactive protein: a prospective study in Japanese factory workers.

We investigated the relation between overall sleep status based on the modified Pittsburgh Sleep Quality Index (PSQI) global score and subsequent changes in serum high-sensitivity C-reactive protein (hsCRP) in a population of Japanese factory workers, who were predominantly female. A total of 991 Japanese with inflammation classified as low cardiovascular risk (baseline hsCRP < 1.0 mg L(-1) ) were grouped according to the presence or absence of unfavourable sleep, defined as a modified PSQI global score > 5.5 points. The subsequent changes in hsCRP after 3 years were then compared in the two groups. Analysis of covariance incorporating log-transformed baseline hsCRP, age, sex, lifestyle and physical and biochemical profiles was used to compare the geometric means of hsCRP at year 3 in each sleep status group. A logistic regression model incorporating the same variables was used to calculate the odds ratios for development of inflammation with a medium-to-high cardiovascular risk (hsCRP at year 3 ≥ 1.0 mg L(-1) ) comparing the presence or absence of unfavourable sleep habits. The multivariate-adjusted geometric mean of hsCRP at year 3 was significantly higher in subjects with unfavourable sleep habits compared with those with a normal pattern (0.275 versus 0.242 mg L(-1) ). The multivariate-adjusted odds ratio for developing increased and potentially pathogenic levels of inflammation due to unfavourable sleep was 2.08 (95% confidence interval = 1.29-3.35). There was a significant linear trend for the development of increased inflammation across the modified PSQI global scores (P = 0.04). Unfavourable sleep is associated with activation of low-grade systemic inflammation.

Correlation between shift-work-related sleep problems and heavy drinking in Japanese male factory workers.

AIMS: To investigate the effects of shift work on increased alcohol intake associated with poor sleep quality. METHODS: This cross-sectional survey evaluated the correlation between work schedule, poor sleep quality and heavy drinking among 909 factory workers aged 35-54 years in Japan. Subjects included 530 day workers, 72 shift workers who did not work at night and 290 shift workers who engaged in night work. Heavy drinking was defined as a mean volume of alcohol consumption exceeding 60 g/day. RESULTS: Compared with other workers, night-shift workers who suffered poor sleep quality exhibited the highest frequency of heavy drinking (17.6%). Multiple logistic regression analysis demonstrated that compared with day workers with good sleep, night-shift workers who experienced poor sleep had more than twice the odds of heavy alcohol consumption (odds ratio 2.17 [95% confidence interval (CI), 1.20-3.93]). Shift workers who did not work at night and day workers with poor sleep were not at increased odds of heavy drinking. CONCLUSION: Shift workers who engage in night work may try to modify their health behavior to cope with sleep problems. Such modification may be a risk factor for heavy drinking.

The effects of continuing and discontinuing smoking on the development of chronic kidney disease (CKD) in the healthy middle-aged working population in Japan.

OBJECTIVES: The strength of the association between smoking and the development of chronic kidney disease (CKD) in the healthy middle-aged working age population has not been established. METHODS: This was a retrospective 6-year observational study involving 4,121 male and 2,877 female workers who were free of primary kidney disease, diabetes mellitus, severe hypertension, and the signs and symptoms of CKD. Proteinuria was detected by a dipstick method, and glomerular filtration rate (GFR) was estimated by the equation of the Japan Society of Nephrology. RESULTS: Sixty men (1.5 %) and 21 women (0.7 %) developed proteinuria over the 6 years of the study. Irrespective of sex, in comparison with non-smokers, those who continued smoking showed an odds ratio (OR) of 2.52 with a 95 % confidence interval (CI) of 1.50-4.25 for developing proteinuria while those who quit smoking showed an OR of 1.29 (95 % CI 0.48-3.42), following adjustment for confounders. Among the study population, 443 men (10.7 %) and 356 women (12.4 %) developed a GFR of <60 mL/min/1.73 m(2), corresponding to stage III CKD. Continuing smokers had a low OR (0.74, 95 % CI 0.60-0.90) for developing a low GFR, as well as a higher mean GFR than non-smokers. The reduction in GFR during the 6-year study period was not different between smokers and non-smokers, but it was larger in those who developed proteinuria than in those who did not, irrespective of smoking. CONCLUSIONS: Continuing smokers showed a twofold or more higher risk of developing proteinuria. Discontinuation of smoking substantially reduced the risk. A longer observational period may be required to detect the smoking-induced risk of developing stage III CKD in the middle-aged working population.

Distribution of and factors contributing to chronic kidney disease in a middle-aged working population.

OBJECTIVES: To clarify the distribution of chronic kidney disease (CKD) and the factors contributing to its development and progression in middle-aged Japanese workers/employees. METHODS: This was a retrospective study involving 3,964 men and 2,698 women aged 35-64 years in 2009 who had been followed-up until 2003. Data on proteinuria determined with a dipstick and glomerular filtration rate estimated from serum creatinine concentration (eGFR) were collected in the annual health check-ups. RESULTS: Proteinuria was detected in 2.9 and 1.1 % of the men and women, respectively, and total CKD was detected in 16.0 and 16.1 % of the men and women respectively. Moderate or severe CKD associated a high risk of cardiovascular diseases and end-stage kidney disease was found mostly in the male subjects [2.0 (men) vs. 0.6 % (women)]. High-risk CKD was found in 3.3 % of the men aged 55-64 years. A body mass index (BMI) of ≥30, hypertension, diabetes mellitus (DM), current smoking and some job types were independently related to the development of proteinuria, while age, BMI, hypertriglyceridemia, and job types were related to total CKD. The development of high-risk CKD was related to preceding mild CKD signs of reduced eGFR and proteinuria as well as to hypertension, DM, smoking, and job type. CONCLUSIONS: Chronic kidney disease was found in 16 % of middle-aged workers with an equal prevalence in both sexes, while high-risk CKD was found mostly in men, of whom 3.3 % were aged 55-64 years. Obesity, hypertension, DM, smoking and some job types were related to the development and progression of CKD.

Physicians' Resilience as a Positive Effect of COVID-19.

People devoid of COVID-19 may exhibit mental health problems, such as anxiety disorders, depression, panic attack, insomnia, emotional disorder, and suicidal actions. Healthcare workers (HCWs) may also exhibit these problems. Physicians should be careful an "at-risk" population. Physicians revealed higher levels of resilience than the popular workers. Humans with stronger resilience have lower feeling of anxiety and depression. We investigated the risk to physicians from an infected environment to infected patients during the pandemic. The social and psychological support of all HCWs, particularly physicians, is significant in the fight against this pandemic. Physicians working with patients with COVID-19 should set enough time to relax, sleep, and spend time with family. Resilience in physicians facing COVID-19 can induce post-traumatic growth in the future.

Cigarette smoking, proteinuria, and renal function in middle-aged Japanese men from an occupational population.

OBJECTIVES: To clarify the renal effects of cigarette smoking in a middle-aged occupational population because the effects have previously been demonstrated mainly in community populations that included many elderly people who are thought to be vulnerable to such effects. METHODS: In 990 middle-aged men recruited from a chemical plant, proteinuria was measured by a dipstick method and the glomerular filtration rate was estimated (eGFR) using a formula proposed by the Japanese Society of Nephrology. RESULTS: Proteinuria was found in 4.6% of the current smokers and 1.5% of the never-smokers. It was found in 4.8% of the subjects having a Brinkman index (BI) of 400-599 and 6.3% of those having a BI of 600 or above. The odds ratio for proteinuria in them was 2.94 (CI: 1.01-8.55) and 3.61 (CI: 1.29-10.1), respectively, adjusting for possible confounders. The mean eGFR was higher in smokers than in nonsmokers throughout middle age up to 64 years. Normal but high eGFR was found in 6.7% of the current heavy smokers and subnormal eGFR in 5.7% of the largest cumulative cigarette consumers in contrast to 3.0% or less of the never-smokers. Proteinuria was found in 13.3% of the subjects showing subnormal eGFR, specifically in 16.7% of the smokers and 8.3% of the nonsmokers. CONCLUSIONS: Smoking causes proteinuria in working middle-aged men. Smokers tend to have a high eGFR, but those with subnormal eGFR showed proteinuria most frequently. Whether the high eGFR in smokers will eventually decrease and cause proteinuria remains an important focus for further studies.

Association between long working hours and sleep problems in white-collar workers.

The purpose of this study is to examine the association between long work hours and sleep disturbance among white-collar workers. We evaluated 1510 male white-collar full-time employees, between the ages of 18 and 59 years, using a comprehensive sleep quality questionnaire, the Pittsburgh Sleep Quality Index (PSQI). All subjects worked in a light metal products factory in Japan. The mean number of monthly overtime work hours was determined using data from the previous 6 months from timecard records. Subjects were divided into five groups based on quintiles of the mean number of monthly overtime work hours: <26 h month(-1); ≥26 but <40; ≥40 but <50; ≥50 but <63; and >63. Leisure time physical activity, drinking habits just before sleep, presence of family/partner and health status were used as confounding factors in the multiple regression model. The prevalence of short sleep hours, impairment of sleep efficiency and daytime dysfunction among seven components of PSQI increased, in a dose-response relationship, with overtime work hours. The prevalence of high global score (>5.5 points) was highest in workers with overtime hours ≥50 h week(-1). The odds ratios after adjustment for confounding factors for high global score using less than 26 h as a reference group were 1.67 for workers with ≥50 h and <63 h, and 1.87 for workers with 63 h and more. To conclude, the present results suggest that long work hours correlate with reduced sleep quality in a dose-response manner.

The Relationship between the Urinary Cadmium Concentration and Cause-Specific Mortality in Subjects without Severe Renal Damage: A 35-Year Follow-Up Study in a Cadmium-Polluted Area of Japan.

We evaluated the association between urinary cadmium concentration (uCd, µg/g Cr) and risk of cause-specific mortality according to urinary ß2-microglobulin (MG) concentration. Participants were 1383 male and 1700 female inhabitants of the Cd-polluted Kakehashi River basin. The uCd and ß2-MG were evaluated in a survey in 1981-1982, where those participants were followed-up over 35 years later. Among the participants with a urinary ß2-MG < 1000, the hazard ratios (HRs) (95% confidence interval) for mortality were significantly higher in those with a uCd of ≥10.0 compared with <5.0 for cardiovascular disease [HR 1.92 (1.08-3.40) for men, 1.71 (1.07-2.71) for women], pneumonia or influenza [2.10 (1.10-4.00) for men, 2.22 (1.17-4.19) for women], and digestive diseases [for men; 3.81 (1.49-9.74)]. The uCd was significantly associated with mortality from heart failure in women and digestive diseases in men, after adjustment for other causes of death using the Fine and Gray competing risk regression model. For participants with a urinary ß2-MG of ≥1000, no significant association was observed between uCd and any major cause of death. In the absence of kidney damage, Cd may increase the risk of death from cardiovascular disease, pneumonia, and digestive diseases.

The Association between Anthropometric Indices of Obesity and Chronic Kidney Disease in Middle-aged Japanese Men and Women: A Cohort Study.

Objective This study investigated associations between three indices of obesity-the body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR)-and the incidence of chronic kidney disease (CKD). Methods The employees of a company in Japan (1,725 men, 1,186 women; aged 35-55 years) had BMI, WC, and WHtR measured in health examinations. The incidence of CKD was determined at annual medical examinations over a six-year period. The hazard ratios for CKD were calculated using proportional hazard models, and the χ2 statistic was used to compare the strengths of the associations. Results The mean BMI (kg/m2), WC (cm), and WHtR were 23.6, 84.3, and 0.49 for men and 22.3, 79.7, and 0.50 for women, respectively. The incidence of CKD (/1,000 person-years) was 18.1 for men and 8.4 for women. In men, positive linear associations were observed between the BMI, WC, and WHtR and the risk of CKD, even after adjusting for the presence of metabolic abnormalities (p for trend <0.001, 0.012, and 0.023, respectively). In women, a linear association was observed only between the WHtR and CKD, not the BMI or WC (p for trend =0.042, 0.057, and 0.186). The χ2 statistics were the highest for the BMI in both men and women. Conclusion The BMI, WC, and WHtR were linearly associated with the risk of CKD independently of metabolic abnormalities in men, while the associations were weaker or not significant in women. The BMI was the most strongly associated with the incidence of CKD in both men and women.