Hematocrit and risk for hypertension in middle-aged Japanese male office workers

The association of hematocrit with development of hypertension over 9 years was studied in 784 hypertension-free Japanese men aged 40 to 59 years. The age-adjusted relative risk for hypertension above the borderline level and definite hypertension increased in a dose-dependent manner as hematocrit level increased (P for trend: 0.007 and 0.001, respectively). After controls for other potential factors of hypertension, the test for trend across increasing categories of hematocrit level remained as statistical significance for definite hypertension (P=0.015). The multivariate-adjusted relative risk for definite hypertension compared with less than 43.8% of hematocrit level was 1.29 [95% confidence interval (CI): 0.62-2.67] for 43.8 to 45.2% hematocrit level, 1.35 (95% CI: 0.62-2.95) for 45.3 to 46.3% hematocrit level, 1.96 (95% CI: 0.97-3.97) for 46.4 to 48.1% hematocrit level, and 2.06 (95% CI: 1.02-4.15) for 48.2% or more hematocrit level. These results suggest that hematocrit is closely associated with development of hypertension in middle-aged Japanese men.     

Metabolic syndrome and risk of isolated ST-T abnormalities and type 2 diabetes in Japanese male office workers

Using a modified National Cholesterol Education Program (NCEP) definition of the metabolic syndrome (MS) with body mass index instead of waist circumference, we examined the associations of the MS with the risk of developing ST-T abnormalities in 3405 Japanese men aged 35-59 yr who did not have a history of cardiovascular disease or ST-T abnormalities. Of 3405 participants, 3166 men without type 2 diabetes (as diagnosed with the revised criteria of American Diabetes Association) also constituted a non-diabetic cohort. Examinations including electrocardiogram and fasting plasma glucose were repeated annually for 7 subsequent years. The subjects were classified as having ST-T abnormalities or type 2 diabetes when evidence of either of these disorders was found during at least 2 consecutive annual examinations. After adjustment for potential risk factors, the relative risks of ST-T abnormalities were 1.0 (referent), 2.66, 3.07, 4.27, and 8.40 for the presence of 0, 1, 2, 3, and > or =24 components of the MS, respectively (P for trend <0.001). The corresponding results for the risk of type 2 diabetes were 1.0 (referent), 3.49, 7.45, 15.00, and 24.04 (P for trend <0.001). The estimated incident rates for men in the low-WBC count (<7.3 x 10(9) cells/L)/no MS, high-WBC count (> or =7.3 x 10(9) cells/L)/no MS, low-WBC count/yes MS, and high-WBC count/yes MS were 3.4%, 4.6%, 7.4%, and 13.1% for ST-T abnormalities, respectively and were 3.6%, 7.1%, 18.0%, and 27.2% for type 2 diabetes, respectively. The respective multivariate-adjusted relative risks were 1.0 (referent), 1.26, 2.07, and 3.45 for ST-T abnormalities and were 1.0 (referent), 1.75, 5.14, and 6.90 for type 2 diabetes. A modified NCEP MS definition predicts ST-T abnormalities and type 2 diabetes. WBC count adds clinically important information to new-onset ST-T abnormalities and type 2 diabetes.     

Multiple risk factor clustering and risk of hypertension in Japanese male office workers

Major risk factors associated with hypertension (a family history of hypertension, obesity, diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, hyperuricemia, and increased white blood cell counts) were assessed in 5275 Japanese male office workers aged 23-59 years. After controlling for potential risk factors of hypertension, the odds ratio of hypertension compared with the absence of risk factors was 1.91, 2.65, 3.88, 6.54, and 8.18 for the presence of 1, 2, 3, 4, and > or = 5 risk factors, respectively (P for trend < 0.001). Systolic and diastolic blood pressure levels also increased in a dose-dependent manner as the number of risk factors increased. Among men not taking antihypertensive medication, the adjusted mean differences in systolic and diastolic blood pressures (mmHg) were 11.2 and 9.2 between men with the presence of > or = 5 risk factors and men without risk factors, respectively. These results indicate that the accumulation of risk factors is highly associated with the increased risk of hypertension in Japanese men.     

Japanese alcoholic beverage and all cause mortality in Japanese adult men

This article examines whether an association is found between quantity of alcohol consumed and all cause mortality, and a relation is detected between types of alcoholic beverage and all cause mortality in Japanese male adults. A cohort study was performed in three towns located in two former coal mine areas and a rural area in Fukuoka. A mail survey was carried out between 1988 and 1990, and was extended in a follow-up period to 1995 (two towns) and 1999 (one town). 6,652 Japanese men aged from 40 to 69 years responded to a questionnaire that included alcohol consumption and smoking habit. The data were analysed with Cox's proportional hazards model. As regards an association between all cause mortality and quantity of alcohol consumed, statistically significant relations were recognized in occasional drinkers and drinkers with less than 25g ethanol per day (hazard ratio= 0.71, 95% CI: 0.50-0.99; hazard ratio= 0.51, 95% CI: 0.29-0.88, respectively). With respect to drinkers with 25-50g/day and > or =50g/day, no significant relation was observed in the risk for all cause mortality. Comparing all cause mortality for daily drinkers and nondrinkers with respect to the beverage types, a risk was lower for daily drinkers than for nondrinkers with every type of beverage studied. In particular, there was a statistically significant adverse association for all cause mortality among subjects who reported drinking Japanese sake compared with nondrinkers (hazard ratio= 0.45, 95% CI: 0.30-0.68). Alcohol consumption (particularly Japanese sake) is likely to be associated with a reduced hazardous ratio of all cause mortality.     

Cigarette smoking and the risk of the metabolic syndrome in middle-aged Japanese male office workers

To examine the association between cigarette smoking and the risk of the metabolic syndrome (MS), 3649 Japanese male office workers aged 35-59 yr who did not have a history of cardiovascular disease were enrolled in this study. 2994 men without the MS at entry were followed up over a 7-yr period. A modified National Cholesterol Education Program definition with body mass index instead of waist circumference was used for the MS. With adjustment for age, family history of diabetes, alcohol intake, and regular physical activity, the odds ratios of the MS were 1.0 (referent), 1.30 (95% confidence interval (CI), 1.00-1.68), 1.07 (95% CI, 0.82-1.39), 1.17 (95% CI, 0.88-1.56), and 1.66 (95% CI, 1.24-2.20) for never smokers, ex-smokers, and those who smoked 1-20 cigarettes/d, 21-30 cigarettes/d, and > or =31 cigarettes/d, respectively (P for trend for current smokers only =0.006). As for the risk of developing the MS, the respective multivariate-adjusted hazard ratios of developing the MS were 1.0 (referent), 1.43 (95% CI, 1.14-1.79), 1.14 (95% CI, 0.91-1.44), 1.45 (95% CI, 1.14-1.84), and 1.59 (95% CI, 1.24-2.05) (P for trend for current smokers only =0.001). Among men without the MS at entry, body weight gain over 7 yr, compared with never smokers, was significantly higher in smokers who quit smoking. It is important for the prevention of the MS not only to quit smoking but also to prevent weight gain after smoking cessation.     

White blood cell count and clustered features of metabolic syndrome in Japanese male office workers

We assessed the association of white blood cell (WBC) count with different components of metabolic syndrome (MS)-obesity, hypertension, hypercholesterolemia, low high-density lipoprotein cholesterol levels, hypertriglyceridemia, high fasting plasma glucose levels and hyperuricemia-in 5275 Japanese male office workers aged 23-59 years. After controlling for age, smoking and alcohol intake, the relative risks for the presence of 1, 2, 3, 4 and > or =5 features of MS compared with the lowest quintile of WBC count increased in a dose-dependent manner as WBC count increased (P for trend < 0.001 for all) and the increased relative risks for clustered features of MS were more pronounced as the number of features of MS increased. The WBC count increments in subjects with 1, 2, 3, 4 and > or =5 features of MS were 0.28, 0.45, 0.68, 0.76 and 1.40 x10(9) cells/l, respectively, compared with the subjects without features of MS (P for trend < 0.001). These findings indicate a strong association between WBC count and clustered features of MS in middle-aged Japanese men.     

Hours of work and the risk of developing impaired fasting glucose or type 2 diabetes mellitus in Japanese male office workers

OBJECTIVE—To investigate the association between duration of overtime and the development of impaired fasting glucose (IFG) or type 2 diabetes mellitus (DM).
METHODS—A cohort of 1266 Japanese male office workers aged 35-59 years and free of IFG (fasting plasma glucose concentration 6.1-6.9 mmol/l), type 2 DM (fasting plasma glucose concentration of 7.0 mmol/l or more or taking hypoglycaemic medication), history of diabetes, or medication for hypertension were re-examined over 5 successive years after their initial examinations in 1994.
RESULTS—138 men developed IFG or type 2 DM during the 5736 person-years of follow up. After controlling for potential predictors of diabetes, the relative risks of IFG or type 2 DM, compared with those who worked <8.0 hours a day, were 0.82 (95% confidence interval (95% CI) 0.54 to 1.26), 0.69 (95% CI 0.38 to 1.26), 0.63 (95% CI: 0.37 to 1.09), and 0.50 (95% CI: 0.25 to 0.98) for those who worked 8.0-8.9, 9.0-9.9, 10.0-10.9, and of 11.0 hours or more a day, respectively (p for trend=0.020). 87 and 54 men developed IFG and type 2 DM during the 5817 and 5937 person-years of follow up, respectively. The multivariate adjusted relative risks of IFG tended to decrease with an increase in hours of overtime work a day, but did not reach significance (p for trend=0.202). On the other hand, the multivariate adjusted relative risks of type 2 DM significantly decreased with an increase in hours of overtime work a day (p for trend=0.014).
CONCLUSION—Longer overtime is a negative risk factor for the development of IFG or type 2 DM in Japanese male office workers.


Keywords: long overtime; impaired fasting glucose; type 2 diabetes mellitus     

The effect of alcoholic beverage excise tax on alcohol-attributable injury mortalities

This study examines the effect of state excise taxes on different types of alcoholic beverages (spirits, wine, and beer) on alcohol-attributable injury mortalities—deaths caused by motor vehicle accidents, suicides, homicides, and falls—in the United States between 1995 and 2004, using state-level panel data. There is evidence that injury deaths attributable to alcohol respond differently to changes in state excise taxes on alcohol-specific beverages. This study examines the direct relationship between injury deaths and excise taxes without testing the degree of the association between excise taxes and alcohol consumption. The study finds that beer taxes are negatively related to motor vehicle accident mortality, while wine taxes are negatively associated with suicides and falls. The positive coefficient of the spirit taxes on falls implies a substitution effect between spirits and wine, suggesting that an increase in spirit tax will cause spirit buyers to purchase more wine. This study finds no evidence of a relationship between homicides and state excise taxes on alcohol. Thus, the study concludes that injury deaths attributable to alcohol respond differently to the excise taxes on different types of alcoholic beverages.     

A cluster of male breast cancer in office workers

Three cases of male breast cancer were diagnosed among a small group of men who worked in a basement office of a multi-story office building. This office was adjacent to an electrical switchgear room which generated high magnetic fields in their work space. The risk of male breast cancer in this group was increased about 100-fold (observe three cases, expect 0.03 cases; P < 0.00001). Since 1991, 15 epidemiologic studies have associated male breast cancer with exposure to electromagnetic field.     

Cigarette smoking and risk for hearing impairment: a longitudinal study in Japanese male office workers

The association of cigarette smoking with development of hearing impairment (loss of 30 dB at 1000 Hz and 40 dB at 4000 Hz) over a 5-year follow-up was studied in 1554 non-hearing-impaired Japanese male office workers who ranged in age from 30 to 59 years. After controlling for potential predictors of hearing impairment, the relative risk for low-frequency hearing impairment compared with never smokers was 1.12 (95% confidence interval [CI], 0.57 to 2.17) for ever-smokers, 1.21 (95% CI, 0.65 to 2.25) for current smokers of 1 to 20 cigarettes/day, 1.35 (95% CI, 0.70 to 2.61) for current smokers of 21 to 30 cigarettes/day, and 1.82 (95% CI, 0.98 to 3.38) for current smokers of 31 or more cigarettes/day (P for trend = 0.063). The respective multivariate-adjusted relative risks for high-frequency hearing impairment compared with never smokers were 1.70 (95% CI, 0.85 to 3.40), 1.82 (95% CI, 0.92 to 3.59), 2.00 (95% CI, 0.98 to 4.08), and 2.20 (95% CI, 1.09 to 4.42) (P for trend = 0.025). As the number of pack-years of exposure increased, the risk for high-frequency hearing impairment increased in a dose-dependent manner (P for trend = 0.011), but the risk for low-frequency hearing impairment did not (P for trend = 0.172). Our results indicate that cigarette smoking is highly associated with development of high-frequency hearing impairment in Japanese male office workers.     

Associations between white blood cell count and features of the metabolic syndrome in Japanese male office workers

We assessed the association of white blood cell (WBC) count with different components of the metabolic syndrome (MS) in 5275 Japanese male office workers aged 23-59 years. There was a significantly crude correlation between WBC count and body mass index, systolic and diastolic blood pressures, total cholesterol, high-density lipoprotein cholesterol (negative), triglycerides, fasting plasma glucose, and uric acid (all P<0.001). After controlling for potential confounding factors, the adjusted means of WBC count were significantly higher in subjects with each feature of the MS (obesity, hypertension, hypercholesterolemia, low high-density lipoprotein cholesterol levels, hypertriglyceridemia, high fasting plasma glucose levels, and hyperuricemia) (all P<0.005). The adjusted WBC count increments in subjects with 1, 2, 3, 4, and > or = 5 features of the MS were 0.28, 0.45, 0.68, 0.76, and 1.40 x 10(9) cells/l, respectively, compared with the subjects without features of the MS (P for trend<0.001). The adjusted means of WBC count increased significantly with the increasing number of features of the MS in both non-smokers and smokers (both P<0.001). These data indicate a strong association between WBC count and a number of disorders characterizing the MS independent of cigarette smoking among Japanese men.     

Association between lifestyle and white blood cell count: a study of Japanese male office workers

METHODS: We assessed the association of lifestyle factors with white blood cell (WBC) count in 3681 Japanese male office workers aged 35-59 years. RESULTS: The WBC count differed significantly across lifestyle factors (overall obesity, alcohol consumption, cigarette smoking, eating breakfast, nutritional balance, physical exercise and hours of work). From multiple linear regression analyses, overall obesity, alcohol intake, cigarette smoking, nutritional balance and hours of work remained as statistically significant factors associated with WBC count. The WBC count increment showed a positive dose-response relationship with poor lifestyle factors regarding overall obesity, cigarette smoking and nutritional balance. On the other hand, the WBC count increment showed a negative dose-response relationship with alcohol intake and hours of work. CONCLUSION: These data indicate that lifestyle factors may exert an important effect on WBC count.     

Hematocrit correlates with blood pressure in young male office workers

High hematocrit (Ht) level has been reported to be a correlating factor of hypertension in aged people, but has not been examined in younger generation. To investigate the association between Ht and blood pressure (BP) in healthy young workers, statistical analysis was performed for 646 male employees, using cross-sectional health-check data. Ht was positively correlated with systolic blood pressure (SBP) and with diastolic blood pressure (DBP) by Pearson's simple correlation analysis. Multiple regression analysis for SBP and DBP was conducted by stepwise procedure, using Ht, age, body mass index (BMI), and drinking and smoking habits as independent variables. It was revealed that Ht was a significant independent variable for DBP (p < 0.001), as well as age and BMI, but not for SBP. These findings suggest that increased Ht is an important variable for assessing risk for cardiovascular disorders, especially diastolic hypertension, in young male office workers.     

Predisposing factors of sleep-disordered breathing in Japanese male workers

The aim of this study was to elucidate the usable predisposing factors of sleep-disordered breathing (SDB) in the workplace. A total of 353 male workers who complained of SDB related symptoms such as witnessed snoring, recurrent awakening from sleep, urination during the night, morning headache, and excessive daytime sleepiness were included in the analysis. We examined hyoid-mental distance (HMD), modified Mallampati score (MMS), and the narrowness of the pharynx with tonsillar hypertrophy as the predisposing physical findings of SDB. We used the number of 3% or more oxygen desaturation events per hour (ODI3) as the indicator of SDB. The mean values (S.D.) of all subjects were 44.3 (8.9) yr (19-66 yr) of age, and 25.9 (3.8) Kg/m(2) body mass index (BMI). A significant difference in ODI3 was found between the HMD classes, and also between the subjects with and without tonsillar hypertrophy. Mean ODI3 adjusted for age, BMI, and alcohol consumption on the day of monitoring was high in the group of short HMD and the group of tonsillar hypertrophy (+). For MMS, though ODI3 did not appear to be significantly different, mean ODI3 was high in the MMS-IV. In conclusion, short HMD and tonsillar hypertrophy are the important findings predicting SDB identified by pulse oximetry. These findings would be beneficial in the workplace for selection of subjects who should be encouraged to undergo pulse oximetry for detection of SDB.     

Relation of body weight change to changes in atherogenic traits; a study of middle-aged Japanese obese male office workers

We examined the effect of body weight change on the modification of atherogenic risk factors in 296 middle-aged obese male office workers without medication for hypertension, dyslipidemia, hyperuricemia or diabetes mellitus. During a 1-year education program, 39.2% of the participants could reduce their weight, and the percentage of those who lost 2 kg or more was only 17.7%. Concomitant with the decrease of weight, however, the levels of systolic and diastolic blood pressures, total cholesterol, triglyceride, uric acid and hemoglobin A1c and the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol decreased significantly, whereas the HDL cholesterol level increased significantly. In a multivariate regression analysis, in addition to the initial risk-factor level, weight change was an important factor determining the changes in atherogenic risk factors. Changes in alcohol consumption were significantly associated with the changes in systolic blood pressure and HDL cholesterol levels. Changes in cigarettes smoking also showed significant associations with the changes in triglyceride level and the ratio of total cholesterol to HDL cholesterol. These results suggest that although the education program for controlling weight may have limited success, weight reduction exhibits beneficial changes in the atherogenic risk-factor profile in middle-aged obese men.     

Lifestyle and the development of hypertension: a 3-year follow-up study of middle-aged Japanese male office workers.

The association of lifestyle factors with the development of hypertension (blood pressure > or = 140/90 mmHg) over a 3-year follow-up period was studied in 949 hypertension-free Japanese male office workers aged 35 to 54 years. From the Cox proportional hazards model, age, alcohol intake, body mass index (BMI) and hours of work were independent factors associated with the development of hypertension. Adjusted hazard ratios for 5-year increases in age, daily consumption of alcohol, 5-kg/m2 increases in BMI and working 10 hours per day or more were 1.18 [95% confidence interval (CI) = 1.02-1.35]; 1.53 (CI = 1.14-2.05); 1.79 (CI = 1.38-2.33) and 0.58 (CI = 0.41-0.82), respectively. In the analysis using logistic regression, BMI was independently related to working 10 hours per day or more, controlling for other lifestyle factors. Adjusted odds ratio for 5-kg/m2 increase in BMI was 0.66 (CI = 0.49-0.88). These results suggest that the influences of long working hours on blood pressure are likely to be indirectly mediated through less overall obesity.     

A chronological decrease in type A behavior patterns among Japanese male workers in 1995-1999

We examined the chronological change in Type A behavior pattern (TABP) among Japanese male workers for 5 yr. A brief questionnaire to measure TABP was administered to 21,711 male workers who underwent health check-ups at least once during the period from 1995 to 1999 and were born in 1936-1965. The mean TABP scores decreased year by year linearly. Then the repeated measurement analysis of variance was performed with the data of 5,689 subjects who completed the questionnaire successively through the study period. Both year and the age effects were highly significant (p<0.001, respectively), whereas the time trends were comparable by baseline age. In conclusion, TABP among Japanese male workers decreased in all generations during the period from 1995 to 1999.     

Associations of body mass index and percentage body fat by bioelectrical impedance analysis with cardiovascular risk factors in Japanese male office workers

To determine whether body mass index (BMI, kg/m2) or percentage body fat (%BF) by bioelectrical impedance analysis (BIA) better reflects the cardiovascular risk profile, we examined the associations among BMI, %BF by BIA, and cardiovascular risk factors (systolic blood pressure (SBP), diastolic blood pressure (SBP), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), LDL-C/HDL-C ratio, and triglycerides (TG)) in 1,217 Japanese male office workers aged 25 to 59 years. From stepwise regression analyses of cardiovascular risk factors on age, BMI, alcohol intake, and cigarette smoking, significant correlates were, in the order of relative importance: age, BMI, and alcohol intake for SBP and DBP (the cumulative percentage of variation; 14.9% and 21.3%, respectively); age, BMI, and alcohol intake (negative) for LDL-C (11.0%); BMI (negative), alcohol, and cigarette smoking (negative) for HDL-C (19.9%); BMI, alcohol intake (negative), age, and cigarette smoking for LDL-C/HDL-C ratio (23.1%); and BMI, age, cigarette smoking, and alcohol intake for Log TG (21.7%). From stepwise regression analyses using %BF by BIA as an independent factor, %BF by BIA was also significantly associated with each cardiovascular risk factor, but the decrease in explained variance for each cardiovascular risk factor was 0.2-4.5%, compared with the model using BMI as an independent factor. These results suggest that BMI may better reflect blood pressure or serum lipid profile than %BF by BIA.