Independent and interactive effects of kidney stone formation and conventional risk factors for chronic kidney disease: a follow-up study of Japanese men.

PURPOSE: To assess the impact of interactions between kidney stone formation and conventional risk factors on incident chronic kidney disease (CKD). METHODS: A total of 11,402 subjects (men 30-69 years of age, Japanese) without CKD at baseline were observed over an average period of 4 years. Cox proportional hazards regression models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) to determine the association between incident CKD, kidney stone formation, and conventional risk factors (diabetes mellitus, hypertension, overweight/obesity, dyslipidemia, and hyperuricemia/gout). We also examined the interactions of renal stones and the conventional risk factors for CKD. RESULTS: In total, 2301 men (20.2%) developed incident CKD during the follow-up period. After multivariable adjustment, kidney stones were found to increase the risk of incident CKD (HR 1.16; 95% CI 1.03-1.32). Kidney stone formers with hypertension, dyslipidemia, or hyperuricemia/gout presented a greater risk for incident CKD than those who had either kidney stones or other risk factors. However, no significant interactions between kidney stones and other risk factors were found to increase CKD risk. On the other hand, a negative interactive effect between kidney stones and overweight/obesity was observed, leading to reversed risk of incident CKD in coexistence of both factors. CONCLUSION: Kidney stones were linked to a higher risk for the development of CKD. However, no positive interactive effects were identified between renal stones and conventional risk factors on the risk of incident CKD.

Long working hours directly and indirectly (via short sleep duration) induce headache even in healthy white-collar men: cross-sectional and 1-year follow-up analyses.

OBJECTIVE: Headache in employees may be linked with both overwork and sleep restriction induced by long working hours. Inter-relationships among working hours, sleep duration and headache were investigated. METHODS: Cross-sectional analyses for prevalent headache (n = 35,908) and 1-year follow-up analyses for incident headache (n = 19,788) were conducted in apparently healthy white-collar men aged 25-59 years. Headache (yes/no), working hours and sleep duration were based on self-administered questionnaire. After determination of relationships between working hours and sleep duration, logistic regression analysis estimated odds ratio (OR) and 95% confidence interval for prevalent and incident headache according to working hours (35-44, 45-49, 50-59 and ≥60 h/week) and sleep duration (≥7, 6-6.9, 5-5.9 and <5 h/day), and tested linear trends in OR. Additionally, interactive effects of working hours and sleep duration on OR were checked. Covariates in the analyses were age, body mass index, drinking, smoking and exercise. RESULTS: Prevalent and incident headache was found in 1979 (5.5%) men and 707 (3.6%) men, respectively. Working hours were inversely associated with sleep duration. OR for prevalent and incident headache rose with increasing working hours and with reducing sleep duration, regardless of influences of the covariates. Working hours and sleep duration had no interactive effects on OR for prevalent or incident headache. CONCLUSIONS: The results indicate that long working hours directly and indirectly (via short sleep duration) induce headache even in apparently healthy white-collar men. Headache in employees may be useful for early detection of adverse health effects by long working hours.

Author Correction: Long working hours directly and indirectly (via short sleep duration) induce headache even in healthy white-collar men: cross-sectional and 1-year follow-up analyses.

Author Correction: Int Arch Occup Environ Health DOI 10.1007/s00420-017-1255-6.

Kidney stone formation is positively associated with conventional risk factors for coronary heart disease in Japanese men.

PURPOSE: We investigated the association between kidney stones and coronary heart disease risk factors in Japanese men. MATERIALS AND METHODS: This cross-sectional study included 13,418 Japanese men 30 to 69 years old who voluntarily underwent medical examination between April 1995 and March 2001. Participants were divided into controls, and past and current kidney stone formers based on ultrasound results and medical history. We evaluated conventional risk factors of coronary heart disease, including overweight/obesity, hypertension, diabetes mellitus, gout/hyperuricemia, dyslipidemia and chronic kidney disease. Associations between coronary heart disease risk factors and kidney stones were investigated. RESULTS: Of the 13,418 participants 404 current kidney stone formers (3.0%) had kidney stones on ultrasound and 1,231 past kidney stone formers (9.2%) had a history of kidney stones but no kidney stones on medical examination. Body mass index, systolic and diastolic blood pressure, and serum uric acid were significantly higher in past and current kidney stone formers than in controls. Logistic regression analysis indicated that the multivariate adjusted OR for overweight/obesity, hypertension, gout/hyperuricemia and chronic kidney disease significantly increased in the order corresponding to controls, and past and current kidney stone formers. CONCLUSIONS: Kidney stone formers, even past stone formers, are likely to have accumulated risk factors for coronary heart disease. They could be preferentially targeted for coronary heart disease prevention.

Serum dehydroepiandrosterone-sulfate reflects age better than health status, and may increase with cigarette smoking and alcohol drinking in middle-aged men.

BACKGROUND AND AIMS: Serum dehydroepiandrosterone- sulfate (DHEAS), the most abundant adrenal steroid hormone, may predict aging status and longevity in humans. The aims of this study are to clarify the fundamental properties of serum DHEAS as a biomarker for health in middle-aged men. METHODS: We investigated correlations of serum DHEAS with age or conventional health indices (body mass index, blood pressure, and 12 serum/blood tests) and associations of serum DHEAS with lifestyle factors (smoking, drinking, exercise, sleep) in 384 healthy men aged 30-49 years, randomly selected from voluntary attendees at a checkup. RESULTS: Serum DHEAS had an inverse and stronger correlation with age (Spearman's r=-0.320, p<0.001) than with any conventional health indices used here. Regardless of age and BMI adjustments, serum DHEAS had a weak correlation with serum uric acid (crude Spearman's r=0.198, p<0.001), and its correlations with other conventional health indices were weaker or non-significant. Serum DHEAS rose in parallel with increased smoking and alcohol intake (p for trend <0.001 in both), but had no significant relationships with exercise or sleep. CONCLUSIONS: Serum DHEAS reflects age better than health status evaluated by conventional health indices, and may increase with cigarette smoking and alcohol drinking in middle-aged healthy men.

Impact of insulin resistance, insulin and adiponectin on kidney stones in the Japanese population.

OBJECTIVES: It has been reported that kidney stones are linked to metabolic syndrome (MetS), which is characterized by insulin resistance. The aim of the present study was to examine the association of insulin resistance, insulin and adiponectin with kidney stones in a Japanese population. METHODS: From February 2007 to March 2008, 1036 (529 men and 507 women) apparently healthy Japanese subjects, aged 35-79 years, were analyzed. Weight, height, waist circumference and blood pressure were measured. Overnight fasting blood was collected to measure insulin and adiponectin levels. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated to assess insulin resistance. Logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence intervals for a self-reported history of kidney stones across tertiles of HOMA-IR, insulin and adiponectin. RESULTS: Of the participants, 84 men (15.6%) and 35 women (6.9%) had a history of kidney stones. Age, body mass index, waist circumference, systolic and diastolic blood pressures, HOMA-IR and insulin were significantly higher in women with than in women without kidney stones. There was no difference in adiponectin level between subjects with and without a history of kidney stones in either sex. Furthermore, a significant positive trend was observed in the age-adjusted OR for a history of kidney stones across insulin tertiles (P-value for trend = 0.04) in women. CONCLUSIONS: For Japanese women, HOMA-IR and insulin are associated with a history of kidney stones. The findings suggest that MetS components could increase the risk of kidney stones through subclinical hyperinsulinemia and insulin resistance.

Genetic polymorphisms of glutathione S-transferase genes and susceptibility to colorectal cancer: a case-control study in an Indian population.

BACKGROUND: Susceptibility to sporadic colorectal cancer is multifactorial and arises from interactive combinations of allelic variants in low-penetrance genes and relevant environmental risk factors. Genetic polymorphisms in metabolic enzymes as gene susceptibility factors may modify colorectal cancer risk. We evaluated the risk of colorectal cancer associated with respective or combined glutathione S-transferase (GST) polymorphisms and assessed the interactions between genes and environmental factors in a case-control study in an Indian population. METHODS: The study included 59 colon and 243 rectal cancer cases, and 291 cancer-free healthy controls. GST genotypes were detected by multiplex PCR-based and PCR-RFLP methods. The risk of cancer associated with GST polymorphisms was estimated by calculation of odds ratios (ORs) and confidence intervals (95% CIs) using unconditional logistic regression. RESULTS: The GSTM1 null genotype was found to be associated with a significantly increased rectal cancer risk (OR=1.55; 95% CI, 1.05-2.30), while the GSTT1 null genotype with a greater risk of colon cancer (OR=2.15; 95% CI, 1.04-4.32). A substantial increase of both colon (OR=10.81; 95% CI, 1.11-107.22) and rectal (OR=4.80; 95% CI, 0.94-35.91) cancer risk was shown for the combination of GSTM1 null, GSTT1 null and GSTP1 105Val allele. The combined GSTM1 null and GSTP1 114Val allele also revealed an increased risk for either colon cancer (OR=4.69; 95% CI, 0.84-23.87) or rectal cancer (OR=5.68; 95% CI, 1.79-22.16). Furthermore, the combination of GSTM1 null, GSTT1 null and GSTP1 114Val allele was found in 2 rectal cancer cases. CONCLUSION: Our results suggest that co-exist of GSTM1 null, GSTT1 null and the variant GSTP1 105Val or 114Val allele may be predisposing risk factors for colorectal cancer in Indian population.

Polymorphisms in DNA repair genes XRCC1, XRCC3 and XPD, and colorectal cancer risk: a case-control study in an Indian population.

PURPOSE: Genetic polymorphisms in DNA repair genes may influence variations in individual DNA repair capacity, which could be associated with the development of cancer. We detected the distributions of three single-nucleotide polymorphisms (XRCC1 Arg399Gln, XRCC3 Thr241Met and XPD Lys751Gln) in DNA repair genes, and assessed the associations of these genetic polymorphisms with colon and rectal cancer susceptibility as well as evaluated the interactions of gene-gene and gene-environment in a case-control study of an Indian population. METHODS: This case-control study was conducted with 302 cases (including 59 colon and 243 rectal cancer patients) and 291 cancer-free healthy controls. Genotypes were determined by PCR-RLFP assays. The effects [odds ratios (ORs) and 95% confidence intervals (95% CIs)] of genetic polymorphisms on colorectal cancer were estimated using unconditional logistic regression. RESULTS: The XRCC1 399Gln allele was found to be associated with a significantly increased rectal cancer risk among men (OR = 1.65, 95% CI 1.04-2.64). Whereas the XRCC3 241Met allele showed a protective tendency against rectal cancer (OR = 0.68, 95% CI 0.46-1.02) for both men and women. Furthermore, a combination of the XRCC1 399Gln allele with XRCC3 Thr/Thr genotype and the XPD 751Gln allele demonstrated the highest rectal cancer risk (OR = 3.52, 95% CI 1.43-9.44). CONCLUSIONS: The combined effects of putative risk alleles/genotypes for different DNA repair pathways may strengthen the susceptibility to rectal cancer.

Heart rate-corrected QT interval in resting ECG predicts the risk for development of type-2 diabetes mellitus.

Chronic and subclinical sympathetic over-activity may underlie development of type-2 diabetes mellitus (DM). Since longer heart rate-corrected QT interval (QTc) represents predominance of sympathetic activity within autonomic balance, we investigated influences of QTc on the incidence of DM in a follow-up study. The subjects were 12,530 men and 7,163 women aged 30-59 years and apparently healthy at baseline. QTc in resting ECG was obtained using Bazett's formula (QTcB), Fridericia's formula (QTcF) and the linear regression technique (QTcLR). Incident DM was identified by 'fasting serum glucose > or =7.00 mmol l(-1) (126 mg dl(-1))' or/and 'on medication for DM'. Using Cox proportional hazard models, hazard ratio (HR) for incident DM was estimated according to the quartiles (Q1-Q4) of QTcB, QTcF or QTcLR, and its linear trends across the quartiles were checked. Baseline age, BMI, smoking, drinking, exercise and education were computed as conventional confounders. During the follow-up of 93,337 person-years for men and 51,517 person-years for women, 637 men and 192 women developed DM. The multivariate-adjusted HRs(95% confidence interval) for Q4 of QTcB, QTcF and QTcLR against corresponding Q1 were 1.85(1.46, 2.34), 1.31(1.04, 1.65) and 1.58(1.26, 1.99), respectively, for men, and 2.03(1.31, 3.16), 1.34(0.91, 2.00) and 1.58(1.04, 2.38), respectively, for women. Both sexes showed increasing trends in the HRs across the quartiles of QTcB, QTcF and QTcLR. In conclusion, QTc in resting ECG moderately but proportionally predicts the risk for development of DM in middle-aged healthy men and women. Moreover, the adverse effects of prolonged QTc are independent of those of conventional risk factors.

Resting heart rate and blood pressure, independent of each other, proportionally raise the risk for type-2 diabetes mellitus.

BACKGROUND: Fast heart rate and high blood pressure (BP) at rest may raise risk for the development of type-2 diabetes mellitus (DM). We therefore investigated dose-response and interactive effects of resting heart rate and BP on the incidence of DM in a Japanese population. METHODS: A follow-up study was conducted for 16 828 men and 8368 women aged 30-59 years and apparently healthy at baseline. Incident DM was identified by 'fasting serum glucose > or =7.00 mmol/l (126 mg/dl)' or/and 'under medical treatment for DM'. Using Cox proportional hazard models, hazard ratio (HR) for incident DM were estimated according to the quartiles of heart rate, systolic or diastolic BP (SBP, DBP), and its linear trends were checked by computing the three indices as continuous variables. Subsequently, interactive effects of slow/fast heart rate (dichotomized by the median) and low/high SBP or DBP (dichotomized by the median) on HR were examined. Baseline age, body mass index, smoking, drinking, exercise and education were computed as conventional confounders. RESULTS: During the follow-up of 125 106 person-years for men and 59 616 person-years for women, 869 men and 224 women developed DM. The multivariate-adjusted HR for incident DM increased across quartiles of heart rate, SBP and DBP in both sexes (linear trend P<0.001 for all). Neither sex showed any significant interactive effects of heart rate and SBP or DBP on HR. CONCLUSIONS: Resting heart rate and BP proportionally raise the risk for DM in middle-aged healthy men and women. Moreover, the adverse effects of fast heart rate and high BP are independent of each other as well as of the influences of conventional confounders.

Sex and seasonal variations of plasma retinol, alpha-tocopherol, and carotenoid concentrations in Japanese dietitians.

AIM: To clarify sex and seasonal variations of plasma antioxidant concentrations among middle-aged Japanese. SUBJECTS AND METHODS: We investigated sex and seasonal variations of plasma antioxidant concentrations, including retinol, alpha-tocopherol, and carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and lycopene), in 55 middle-aged dietitians (46 women and 9 men) in Aichi Prefecture, Central Japan, who took no supplements from autumn 1996 to summer 1997. Reversed-phase high performance liquid chromatography was used to measure plasma antioxidant concentrations in overnight-fasting blood samples. RESULTS: Plasma levels of alpha-tocopherol, alpha-/beta-carotene, b-cryptoxanthin and lutein were significantly influenced by sex, being significantly higher for women than men in each corresponding season; retinol and lycopene, however, showed no such difference. For women, winter values of alpha-tocopherol, alpha-/beta-carotene, lutein and lycopene were significantly lower than corresponding summer values, and had reached their annual lowest. Retinol failed to show any significant seasonal variation, whereas the winter value of beta-cryptoxanthin had reached its annual highest. For men, beta-cryptoxanthin exhibited significant seasonal changes and was also highest in winter. Winter values of alpha-tocopherol, alpha-/beta-carotene and lycopene were lower compared with other seasons, but not statistically significant, probably due to the small sample size. CONCLUSIONS: The findings indicate that sex and seasonal variations of plasma antioxidant concentrations should be taken into account in nutritional epidemiologic studies.

Inverse relationship between obesity and serum prostate-specific antigen level in healthy Japanese men: a hospital-based cross-sectional survey, 2004-2006.

OBJECTIVES: To confirm an inverse relationship between obesity and serum prostate-specific antigen (PSA) levels in Japanese men with a smaller body mass index (BMI) than white and African-American men. METHODS: We analyzed 5246 apparently healthy Japanese men aged >20 years who visited our medical center for a health checkup from January 2004 to December 2006. The men were divided into 6 groups by age decade, and the BMI was categorized into 5 groups. The body fat percentage (BFP) was also used and was grouped into quartiles. The Mantel-Haenszel chi(2) test was used to check for trends in proportions of subjects with abnormal PSA values for each cutoff point (2.5 and 4.0 ng/mL) in these groups. The relationships between the PSA levels and BMI or BFP were examined using multivariate analysis. RESULTS: The median age, BMI, BFP, and PSA level was 46 years, 23.2 kg/m(2), 21.5%, and 0.78 ng/mL, respectively. The proportion of subjects with an abnormal PSA value increased significantly with age (P for trend < .0001); however, no trends were found across the BMI or BFP categories. The geometric mean PSA level increased significantly with age (P for linear trend < .0001) and decreased with BMI and BFP categories (P for linear trend = .001 and P for linear trend = .002, respectively). CONCLUSIONS: Our findings have demonstrated an inverse relationship between obesity and PSA levels even in Japanese men with a low prevalence of obesity, such as was previously reported for American men. Therefore, in prostate cancer screening, obesity, which can affect the accuracy of PSA testing, independent of race and ethnicity, should be taken into account.

Heavy smoking raises risk for type 2 diabetes mellitus in obese men; but, light smoking reduces the risk in lean men: a follow-up study in Japan.

PURPOSE: To investigate interactive effects of cigarette smoking and body mass index (BMI, measured in kilograms per square meter) on the risk for type 2 diabetes mellitus (DM). METHODS: We conducted a follow-up study in 16,829 apparently healthy men 30 to 59 years of age. At baseline, 23.1%, 24.6%, 24.0%, and 28.4% of the men were 'never' smokers, ex-smokers, light smokers (20 cigarettes/d), respectively. BMI was expediently categorized into quartiles (Q1: <21.3; Q2: 21.3-22.9; Q3: 23.0-24.7; and Q4: >24.7 kg/m2). Incident DM was identified by a fasting serum glucose level of 7.00 mmol/L or higher or the criterion 'under treatment for DM.' The risk ratio for incident DM, hazard ratio (HR) and the 95% confidence interval (CI), according to smoking and BMI, were estimated by using Cox proportional hazard models. Age, drinking, exercise, and education were computed as confounders. RESULTS: During mean follow-up of 7.4 years, 869 men developed DM. In Q4 of BMI, heavy smoking raised the risk against 'never smoking' (multivariate-adjusted HR (95%CI): 1.37 [1.05-1.80]), but neither light smoking nor ex-smoking did. In Q1 of BMI, light and heavy smoking reduced the risk (multivariate-adjusted HR (95% CI): 0.45 (0.23-0.88) and 0.74 (0.41-1.33), respectively). CONCLUSIONS: Smoking and BMI interactively influence risk for DM and the interaction is considerably complex. Heavy smoking moderately increases the risk for DM in obese men. But, light smoking reduces the risk in lean men.

Cigarette smoking weakens exercise habits in healthy men.

To investigate the longitudinal impact of smoking cessation and relapse on the exercise habits of apparently healthy Japanese men, 750 subjects presenting for a checkup at a metropolitan health center were surveyed annually for 7 years. Exercise was dichotomously classified as none or any. Subjects were grouped in two categories: 98 smokers who ceased smoking during the second year of the study, matched with 196 continuing smokers and 196 men who had never smoked; and 52 relapsed smokers (including 2 new smokers) who did not smoke at baseline or at Year 1 but smoked from Year 2 to final follow-up, matched with 104 continuing smokers and 104 never-smokers. Based on self-reported responses to questionnaires, exercise was consistently less prevalent among smokers who did not quit than among never-smokers throughout the study. Habitual exercise in subjects who had quit smoking increased during the follow-up (any exercise: 42.9% at baseline increased to 51% at final follow-up, p for longitudinal trend = .115). Habitual exercise in matched never-smokers did not change during the study and decreased significantly among persistent smokers (p = .025). Habitual exercise in relapsed smokers decreased during the follow-up (any exercise: 50.0% at baseline declined to 32.7% at final follow-up, p = .007), but habitual exercise in matched persistent smokers and never-smokers did not change. We conclude that smoking and sedentary lifestyle coexist continuously, that smoking cessation is associated with increased habitual exercise among healthy men, and that relapse is associated with reduced habitual exercise, suggesting that cigarette smoking weakens exercise habits.

Incidence of type-2 diabetes mellitus in a large population of Japanese male white-collar workers.

Since occupation, a major socio-economic factor, may be a risk factor for type-2 diabetes mellitus (DM), we compared DM incidence among four groups of white-collar workers in a follow-up study in 13,547 Japanese men. The subjects aged 30-59 years and free from DM at baseline consisted of: (a) 3725 clerical, (b) 5575 technical/professional, (c) 3474 manager/administrative and (d) 774 sales workers. Incident DM was identified by 'fasting serum glucose >or=7.00 mmol/l' or 'under medical treatment for DM'. Hazard ratio (HR) and 95% confidence interval (CI) for incident DM were estimated using clerical workers as the reference group (HR=1.00). Baseline age, body mass index (BMI), drinking, smoking, exercise and education were computed as confounders. During mean follow-up periods of 7.4 years, 176 clerical, 264 technical/professional, 195 manager/administrative and 49 sales workers developed DM (6.0, 6.1, 8.8 and 9.4 per 1000 person-years, respectively). Sales workers aged 40-49 and 50-59 years had increased multivariate-adjusted HRs (95% CIs) of 1.55 (1.02, 2.35) and 2.01 (0.98, 4.10), respectively. Manager/administrative workers aged 50-59 years had an increased crude HR (95% CI) of 1.64 (1.02, 2.63), but the significance disappeared after BMI-adjustment (HR (95% CI: 1.46 (0.91, 2.35)). Technical/professional workers had no significant HR in any model. In conclusion, sales workers in Japan aged >or=40 years may have increased risk for DM (+55 to +100%) independent of BMI, lifestyles and education, and manager/administrative workers aged >or=50 years may have increased risk (about +65%) due to their large BMI.

Associations between 5,10-methylenetetrahydrofolate reductase codon 677 and 1298 genetic polymorphisms and environmental factors with reference to susceptibility to colorectal cancer: a case-control study in an Indian population.

Although the incidence rate of colorectal cancer is very low, and rectal cancer remains more common in India, a significant increase in its incidence has been reported for both men and women over the last 2 decades. We evaluated MTHFR genetic susceptibility and common environmental risk factors in the development of colon and rectal cancer, and assessed the interactions between gene and environmental factors with colorectal cancer in a case-control study in the Indian population. The study included 59 colon cancer cases, 243 rectal cancer cases and 291 controls. The variant MTHFR 677T allele is rare, while the 1298C allele is common among Indians. MTHFR 677T showed no association with colon cancer (OR = 0.82; 95% CI 0.28-2.05) and a nonstatistically significantly elevated risk with rectal cancer (OR = 1.51; 95% CI 0.86-2.68), and MTHFR 1298 CC genotype was found to be associated with a significantly decreased risk for both colon cancer (OR = 0.30, 95% CI 0.09-0.81) and rectal cancer (OR = 0.43, 95% CI 0.23-0.80). High intake of nonfried vegetables or fruits was inversely associated with both colon and rectal cancer risk. Especially, the combination of a high intake of nonfried vegetables and MTHFR 1298CC genotype was associated with the lowest rectal cancer risk (OR = 0.22, 95% CI 0.09-0.52). Regarding alcohol consumption, indigenous Indian alcohol drinkers (OR = 2.26, 95% CI 0.86-6.36), and those consuming alcohol for duration more than 20 years (OR = 1.55, 95% CI 0.73-3.33), were at a somewhat higher rectal cancer risk. Moreover, the consumed alcohol amount (gram-years) may be also associated with colon or rectal cancer risk.

Policemen and firefighters have increased risk for type-2 diabetes mellitus probably due to their large body mass index: a follow-up study in Japanese men.

BACKGROUND: Policemen/firefighters may have increased risk for mortality from ischemic heart disease and from all causes. We compare incidence of type-2 diabetes mellitus (DM), a well-known predictor for mortality, in policemen/firefighters with that in two other worker-groups. METHODS: A follow-up study of 5,130 healthy Japanese men aged 30-49 years at baseline consisted of three worker-groups; 3,111 clerical workers, 1,122 manual/production and transport/communication workers, and 897 policemen/firefighters. Incident DM was identified by "fasting serum glucose >or=7.00 mmol/L" or/and "under medical treatment for DM." Hazard ratio (HR) and 95% confidence interval (95% CI) for incident DM was estimated by Cox's proportional hazard models using clerical workers as a reference group (HR=1.00). Baseline age, body mass index (BMI, kg/m(2)), drinking, smoking, exercise, and education were computed as confounders. RESULTS: During mean follow-up periods of 8.4 years, 155 clerical workers, 51 manual/production and transport/communication workers, and 74 policemen/firefighters had incident DM (5.9, 5.7, and 9.6 per 1,000 person-years, respectively; P=0.001 by chi(2)-test). Policemen/firefighters had significantly increased risk for incident DM against clerical workers (age-adjusted HR (95% CI): 1.65 (1.25, 2.18)), but the significance disappeared after adjustments for BMI (age- and BMI-adjusted HR (95% CI): 1.16 (0.87, 1.54)). Manual/production and transport/communication workers had no increased risk. CONCLUSIONS: Policemen/firefighters have increased risk for DM probably due to their large BMI. Body weight control may be more efficient for prevention of DM and DM-related health problems in policemen/firefighters than in other workers.

Plasma carotenoid, alpha-tocopherol and retinol concentrations and risk of colorectal adenomas: A case-control study in Japan.

To investigate associations between plasma carotenoids, alpha-tocopherol and retinol with colorectal adenomas risk, we measured concentrations in 224 asymptomatic colorectal adenoma cases and 230 population-based controls matched for age and sex. After adjustment for age, history of colorectal adenomas and cancers, BMI, smoking, drinking status, multivitamin consumption and plasma total cholesterol, the risk of colorectal adenomas in the highest quartile was approximately half of that of men in the lowest quartile for alpha-carotene (OR=0.38; 95% CI: 0.18-0.84; P(trend)=0.01), beta-carotene (OR=0.51; 95% CI: 0.24-1.07; P(trend)=0.03) and total carotenoids (OR=0.48; 95% CI: 0.22-1.03; P(trend)=0.04). In addition, a protective association for alpha-carotene in women was also indicated, but which did not reach statistical significance (OR=0.53; 95% CI: 0.19-1.52; P(trend)=0.35). Our findings suggest a protective effect of carotenoids against the development of colorectal adenomas.

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.

Plasma concentrations of (n-3) highly unsaturated fatty acids are good biomarkers of relative dietary fatty acid intakes: a cross-sectional study.

A cross-sectional study was conducted to clarify the associations of lifestyle factors (habitual exercise, alcohol intake and smoking habit) and plasma fatty acid (FA) concentrations as biomarkers of dietary FA intakes. We collected 7-d weighed diet records, lifestyle information and blood samples from 15 male and 79 female Japanese dietitians, and estimated dietary FA intakes and analyzed plasma FA concentrations. Plasma concentrations of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and (n-3) highly unsaturated FA (HUFA) derived from marine foods, but not linoleic and alpha-linolenic acid from plant origins, demonstrated positive correlations with dietary intakes (r = 0.303-0.602, P < 0.05) in both genders. Multiple linear regression analyses adjusted for age, BMI, total energy intake, fat (or respective FA) consumption and lifestyle factors showed that dietary intakes of EPA, DHA and (n-3) HUFA were positively associated with age in men (P < 0.05) and negatively associated with BMI in women [P < 0.01 for DHA and (n-3) HUFA]. The plasma concentrations of EPA, DHA and (n-3) HUFA in women were found to be positively associated with age and marine oil (or respective FA) intake (P < 0.01), and negatively associated with total energy intake [P < 0.05 for EPA and (n-3) HUFA]. Lifestyle factors were not associated with dietary FA intakes and plasma FA concentrations. These findings suggest that the plasma concentrations of EPA, DHA and (n-3) HUFA might be useful biomarkers for the assessment of relative FA intakes without considering associations with habitual exercise, alcohol intake and smoking habit.