Depressive symptoms and oxidative DNA damage in Japanese municipal employees

We sought to explore the relationship between depressive symptoms and urinary 8-hydroxydeoxyguanine (8-OHdG), a biomarker of systemic oxidative DNA damage and repair, among 301 men and 210 women aged 21-67 years working in two municipal offices. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression scale (CES-D). The geometric mean and its 95% confidence interval (CI) of urinary 8-OHdG concentrations were calculated according to the quartile of CES-D score. The prevalence of depressive symptoms, defined as having CES_D of ≥16, was 35.9% in men and 35.2% in women. There was no significant difference in geometric mean of urinary 8-OHdG concentrations according to the levels of depressive symptoms. In men, the multivariable-adjusted geometric mean of urinary 8-OHdG concentrations (95% CIs) in the first, second, third, and fourth category of depressive symptoms was 1.09 (1.02-1.16), 1.16 (1.08-1.24), 1.15 (1.07-1.24), and 1.10 (1.02-1.18), respectively (p for trend=0.86). Similarly, no significant association was found in the analyses among women, nonsmoking men, and smoking men. The lack of association between depressive symptoms and urinary 8-OHdG concentrations may indicate the absence or more complex interactions between milder forms of depression and systemic oxidative DNA damage and repair in well-functioning population.

Response of the Nrf2 protection system in human monocytic cells after ionising irradiation

In response to reactive oxygen species (ROS) or electrophiles, the transcription factor nuclear factor-erythroid 2 (NF-E2)-related factor 2 (Nrf2) rapidly translocates into the nucleus and induces the expression of various antioxidant genes, such as heme oxygenase-1 (HO-1). Low linear energy transfer (LET) ionising radiations such as X-rays generate ROS, which cause biological damage. However, little is known about whether the Nrf2 system in human monocytic cells is activated by low LET ionising irradiation. Therefore, in this study, the response of the Nrf2 system to X-irradiation in human monocytic THP1 cells was investigated. Following exposure of THP1 cells to X-rays (1-5 Gy), intracellular ROS levels were measured using 2',7'-dichlorodihydrofluorescein diacetate, Nrf2 localisation was determined using immunofluorescence staining and HO-1 mRNA and protein expression were examined. Although ROS were generated by irradiation in a dose-dependent manner, they disappeared immediately after irradiation. Nrf2 translocation into the nucleus was observed 6 h after 5 Gy X-irradiation but was not detected following 1-2 Gy irradiation or in non-irradiated controls. HO-1 expression was significantly higher in 5 Gy-irradiated cells after 24 h than in non-irradiated controls. These results indicate that high-dose irradiation (5 Gy) activates Nrf2 and that the Nrf2 protection system may function from 24 h after irradiation in human monocytic cells.

An open-label randomized controlled study of pegylated interferon/ribavirin combination therapy for chronic hepatitis C with versus without fluvastatin

Pegylated interferon (PEG-IFN)/ribavirin combination therapy is the standard-of-care (SOC) treatment for chronic hepatitis C patients infected with hepatitis C virus (HCV) genotype 1b and high viral load. The addition of fluvastatin to SOC treatment has been suggested to be effective for better outcome in retrospective pilot analyses. We investigated whether the combination of fluvastatin with PEG-IFN/ribavirin could actually improve sustained viral response (SVR) in patients with HCV genotype 1b and high viral load. A randomized, open-labeled, controlled study was conducted between July 2008 and December 2009 in 101 chronic hepatitis C patients allocated to PEG-IFN/ribavirin combination therapy with or without fluvastatin. SVR rates were calculated in groups, stratifying host and viral factors. We also analyzed predictive factors for SVR among patients on fluvastatin with multivariate regression analysis. Rapid and early virological, and end of treatment response rates in the fluvastatin group were not significantly different from those in the non-fluvastatin group. Notwithstanding, SVR rate was significantly higher in the fluvastatin group than in the non-fluvastatin group (63.0%vs 41.7%, P = 0.0422). Comparison of the two groups stratifying demographic data and HCV characteristics showed significantly higher SVR rates to more than 80% in males, more than two mutations in the interferon sensitivity determining region (ISDR), and a history of relapse among the fluvastatin group than the non-fluvastatin group. Being male and major genotype IL28B single nucleotide polymorphisms (SNPs) were independent predictive factors for SVR among patients on fluvastatin with multivariate analysis. Fluvastatin-combined with PEG-IFN/ribavirin therapy significantly improves SVR rates in patients with HCV genotype 1b and high viral load. Male and major genotype IL28B SNPs were independent predictors for SVR among patients on fluvastatin combination therapy.

Visceral fat area cutoff for the detection of multiple risk factors of metabolic syndrome in Japanese: the Hitachi Health Study

The relationships between metabolic risk factors and abdominal fat distribution determined using computed tomography (CT) are poorly defined in large populations. We investigated the cutoff values of the visceral fat area (VFA) to detect subjects with multiple risk factors of metabolic syndrome (MS) by sex and age groups, and attempted to examine whether sex- and age-specific cutoff values are needed. The subjects of this study were 11,561 Japanese men and women who participated in the Hitachi Health Study, received CT examination, and answered questionnaires on lifestyles between 2004 and 2009. VFA and waist circumference were measured using CT. The VFA cutoff values yielding an 80% sensitivity for the detection of multiple risk factors of MS were typically smaller among men under the age of 40 years (<40 years vs. ≥40 years; 86.4 cm(2) vs. 103.9 cm(2)). The area under the receiver operator characteristic curve of VFA for the detection tended to decrease according to age (P = 0.056 and P = 0.020 for trends in men and women). Age- and sex-specific cutoff values are needed. The sensitivity of the subjects under the age of 40 years is relatively smaller (70.0% for men and 60.0% for women) compare to other age groups when the same cutoff value is used regardless of age (e.g., cutoff value calculated to correspond to 80% sensitivity for subjects of all ages). Therefore, a smaller VFA cutoff point should be used among men under the age of 40 years.

Dietary patterns and C-peptide concentrations in a Japanese working population

OBJECTIVE

It remains unsettled whether dietary patterns play a role in insulin resistance. We assessed the association of major dietary patterns with C-peptide concentrations in a Japanese working population.

METHODS

A cross-sectional study was conducted in 456 municipal employees (270 men and 186 women) 21 to 67 y old who participated in a health survey at the time of their periodic checkup. The dietary patterns were derived by using the principal component analysis of the consumption of 52 food and beverage items, which was assessed by a validated brief dietary history questionnaire. Multiple regression analysis was used to estimate the means of C-peptide concentrations across tertiles of each dietary pattern score with the adjustment of potential confounders, including age, body mass index, physical activity, smoking, alcohol drinking, and energy intake.

RESULTS

We identified three dietary patterns: healthy, animal food, and Westernized breakfast patterns. The Westernized breakfast pattern was characterized by high intakes of bread, confectionaries, and milk and yogurt but low intakes of rice and alcohol and was inversely associated with C-peptide concentrations in women but not in men. The multivariable-adjusted means of C-peptide concentrations were 1.03 ng/mL (95% confidence interval 0.95-1.12), 0.95 ng/mL (95% confidence interval 0.88-1.03), and 0.89 ng/mL (95% confidence interval 0.82-0.97) for the lowest through the highest tertiles of the Westernized breakfast pattern score (P for trend = 0.015) in women. Other dietary patterns were not appreciably associated with C-peptide concentrations. In a subgroup, similar associations were observed between dietary patterns and the homeostasis model assessment of insulin resistance.

CONCLUSION

The Westernized breakfast pattern may be associated with a lower insulin resistance in Japanese women.

Effect of longitudinal changes in visceral fat area and other anthropometric indices to the changes in metabolic risk factors in Japanese men: the Hitachi Health Study

OBJECTIVE

The effects of longitudinal changes in the visceral fat area (VFA), and other anthropometric indices, on the risk factors of metabolic syndrome were not studied. We calculated the changes in metabolic risk factors in relation to changes in certain anthropometric indices in a large-scale study of Japanese men.

RESEARCH DESIGN AND METHODS

The subjects were 1,106 men participating in the Hitachi Health Study who received a computed tomography examination in both 2004 and 2007. VFA, subcutaneous fat area (SFA), and waist circumference were measured using the computed tomography. We examined how longitudinal changes in each anthropometric index over a 3-year period influenced the value of each metabolic risk factor.

RESULTS

Changes (Δ) over a 3-year period in body weight, SFA, and waist circumference strongly correlated, while the changes in body weight and VFA were weakly correlated. Changes in the VFA were associated with changes in metabolic risk factors, especially changes in triglyceride and HDL; we found these changes to be independent of the body weight and waist circumference.

CONCLUSIONS

Change in body weight is not a precise surrogate marker of VFA, and repeated VFA measurements over time are useful. Adopting a lifestyle that does not increase the VFA is important in preventing metabolic syndrome.

Short sleep duration in association with CT-scanned abdominal fat areas: the Hitachi Health Study

OBJECTIVE

To examine the relationship between short sleep duration and body mass index (BMI), waist circumference (WC), visceral fat area (VFA) and subcutaneous fat area (SFA) among a working population in Japan.

DESIGN

Health-center-based, cross-sectional study.

SUBJECTS

The study subjects included 5400 men and 642 women aged 30 to 75 years who underwent an abdominal computed tomography (CT) scanning examination in a comprehensive health checkup.

MEASUREMENTS

Height and weight were measured, and BMI was calculated. WC, VFA and SFA were measured using a CT scanner. Sleep duration was self-reported. Analysis of covariance was used to estimate adjusted means of BMI, WC, VFA and SFA across categories of sleep duration with adjustments for potential confounders. Trend of the association was assessed using multiple linear regression analysis.

RESULTS

In men, the mean values of BMI, WC and SFA decreased with increasing sleep duration after adjustment for age, physical activity, smoking and drinking (P-value for trend <0.001). Additional adjustment for physical illnesses did not attenuate the explanatory power of the models (P-value for trend <0.001). In addition, the association between sleep duration and SFA did not change after controlling for VFA (P-value for trend <0.001). The mean values of SFA for subjects sleeping '<5 h', '5 to <6 h', '6 to <7 h' and '7 h' per day were 145.8±67.4 cm(2), 138.7±61.5 cm(2), 134.7±60.4 cm(2) and 132.5±49.2 cm(2), respectively. Sleep duration was not appreciably associated with VFA. In women, no significant association was detected in any models.

CONCLUSION

Shorter sleep duration is associated with higher BMI, WC and SFA in men. Further research is needed to explicate the biological mechanisms behind these relationships and to see whether interventions addressing inadequate sleep could treat or prevent obesity by taking gender differences into consideration.

Smoking cessation increases short-term risk of type 2 diabetes irrespective of weight gain: the Japan Public Health Center-Based Prospective Study

Objective

The effect of smoking cessation on the risk of diabetes has been reported previously. However, it is unknown whether the association is influenced by weight gain and other potential risk factors.

Methods

The Japan Public Health Center-Based Prospective Study established in 1990 for Cohort I and in 1993 for Cohort II provided data, and 25,875 men and 33,959 women were analyzed. The response rate to the baseline questionnaire was 80.9%, and 68.4% of the respondents participated both the 5- and 10-year follow-up surveys. Smoking cessation was noted during the initial five years and the development of diabetes was reported in the subsequent five years.

Results

An increased risk was observed among individuals who newly quit smoking compared with never smokers among men (odds ratio (OR) = 1.42, 95% CI = 1.03–1.94) and women (OR = 2.84, CI = 1.53–5.29). The risk of developing diabetes among male new quitters who gained 3 kg or more during the 5-year follow-up did not substantially differ from the risk among male never smokers with less than 3 kg of weight gain or no weight gain, while an increased risk was observed among male new quitters with less or no weight gain (OR = 1.46, 95%CI 1.00–2.14). An insignificant increased risk was observed among male new quitters with a family history of diabetes compared with male never smokers with a family history of diabetes. The risk was more than twice as high for male new quitters who used to smoke 25 or more cigarettes per day compared with never smokers (OR = 2.15, 95%CI: 1.34–3.47).

Discussion

An increased risk of diabetes was implied among individuals who quit smoking. However, the increased risk was not implied among those who gained weight over the 5-years of follow-up. Those who had major risk factors for diabetes or who smoked heavier had a higher risk.

Social support and suicide in Japanese men and women - the Japan Public Health Center (JPHC)-based prospective study

Although the important role of social support in mental health is acknowledged, no prospective study has yet examined the relation of social support to suicide. Here, we investigated the association between social support and suicide in a cohort of Japanese men and women. A total of 26,672 men and 29,865 women aged 40-69 years enrolled in the Japan Public Health Center-based prospective study in 1993-1994 completed a self-administered questionnaire which included four items of social support, and were followed for death through December 2005. Hazard ratios (HRs) and 95% confidence intervals (95% CI) of suicidal death by social support index were estimated using a Cox proportional hazards regression model. A total of 180 suicidal deaths were recorded during an average of 12 years' follow-up. Men and women with the highest level of social support had a significantly decreased risk of suicide, with HRs (95% CI) for the highest versus lowest social support group of 0.56 (0.33-0.94) and 0.38 (0.16-0.89) in men and women, respectively. Esteem support and having four or more friends were associated with a lower risk of suicide in women [0.32 (0.13-0.77)] and in both sexes [men: 0.56 (0.36-0.88); women: 0.65 (0.32-1.30)], respectively, whereas confident support was not. These findings suggest that social support may be important for suicide prevention. Avoiding social isolation may decrease the incidence of suicide in men and women, and esteem support can provide additional benefit for women.

Association between serum ferritin concentrations and depressive symptoms in Japanese municipal employees

It remains unclear whether levels of body iron store are related to milder forms of depression, which are more common among apparently healthy people. We examined the association between serum ferritin concentrations and depressive symptoms among 312 men and 216 women working in two municipal offices in Japan. Depressive symptoms were assessed by using the Center for Epidemiologic Studies Depression (CES-D) scale. In men, increased prevalence of depressive symptoms (defined by using a cutoff value of ≥ 19) was significantly associated with decreased levels of serum ferritin. In age- and study-site-adjusted models, ORs (95% CIs) for depressive symptoms for men in first, second, third, and fourth quartiles of serum ferritin concentrations were 2.83 (1.01-7.94), 1.74 (0.87-3.49), 1.33 (0.71-2.47), and 1.00 (reference), respectively (p for trend=0.02). In multivariate-adjusted model, ORs (95% CIs) in first, second, third, and fourth quartiles of serum ferritin concentrations were 2.88 (0.93-8.91), 1.91 (0.90-4.05), 1.28 (0.66-2.49), and 1.00 (reference), respectively (p for trend=0.03). No significant association was detected in women. Our finding that men with lower levels of serum ferritin concentrations had a higher prevalence of depressive symptoms suggests that adverse psychological effects may be implicated in iron deficiency among middle-age Japanese workers.

Fish intake and type 2 diabetes in Japanese men and women: the Japan Public Health Center-based Prospective Study

BACKGROUND

Although fish intake can improve glucose metabolism, results of some prospective studies in Western populations suggest potential adverse effects of environmental contaminants in fish on type 2 diabetes risk. However, data from populations with high fish consumption are scarce.

OBJECTIVE

We prospectively investigated the association between fish intake and type 2 diabetes risk in Japanese adults.

DESIGN

The participants were 22,921 men and 29,759 women aged 45-75 y who completed a questionnaire of the second survey for the Japan Public Health Center-based Prospective Study and who had no history of diabetes. Diet was ascertained by using a 147-item food-frequency questionnaire. ORs of self-reported, physician-diagnosed type 2 diabetes over 5 y were estimated by using logistic regression.

RESULTS

During the 5-y period, 971 new cases (572 men and 399 women) of type 2 diabetes were self-reported. In men, fish intake was significantly associated with a decreased risk of type 2 diabetes; multivariable-adjusted ORs of type 2 diabetes for the highest compared with the lowest quartile of intake were 0.73 (95% CI: 0.54, 1.00; P-trend = 0.04) for total fish and seafood and 0.68 (95% CI: 0.50, 0.92; P-trend = 0.016) for small and medium fish (horse mackerel and sardine, saury and mackerel, and eel). Additional analysis by fat content of fish did not detect any significant association for each category. In women, fish intake was not appreciably associated with type 2 diabetes risk.

CONCLUSION

In a population with high fish and seafood intake, fish consumption was associated with a lower risk of type 2 diabetes in men but not in women.

Serum 25-hydroxyvitamin d concentrations and season-specific correlates in Japanese adults

Background

Several lines of evidence indicate an important role for vitamin D in the prevention of a range of diseases. Blood vitamin D levels show clear seasonal variation; however, data on the determinants of vitamin D status for each season are limited. We investigated the association between lifestyle and serum vitamin D concentration by season in Japanese workers.

Methods

Subjects were 312 men and 217 women aged 21 to 67 years who worked in municipal offices in Northern Kyushu, Japan and participated in a periodic checkup in July or November. Multiple linear regression analysis was used to examine the association between serum 25-hydroxivitamin D concentrations and lifestyle factors for each season.

Results

Mean serum 25-hydroxyvitamin D concentration was 27.4 ng/ml (68.4 nmol/L) and 21.4 ng/ml (53.4 nmol/L) for workers surveyed in July and November, respectively (P < 0.001); the prevalence of vitamin D deficiency (<20 ng/ml) was 9.3% and 46.7%, respectively (P < 0.001). In November, dietary vitamin D intake (in both sexes) and nonsmoking and physical activity (in men) were significantly associated with higher concentrations of serum 25-hydroxyvitamin D. In summer, fish/shellfish intake was associated with higher serum 25-hydroxyvitamin D concentrations in women.

Conclusions

Vitamin D deficiency is common in Japanese workers during seasons with limited sunlight. The lifestyle correlates of favorable vitamin D status in November were physical activity, dietary vitamin D intake, and nonsmoking.

Long chain n-3 fatty acids intake, fish consumption and suicide in a cohort of Japanese men and women--the Japan Public Health Center-based (JPHC) prospective study

OBJECTIVE

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been implicated as protective against suicide. However, it is uncertain whether a higher intake of EPA and DHA or of fish, a major source of these nutrients, lowers suicidal risk among Japanese, whose fish consumption and suicide rate are both high. This study prospectively examined the relation between fish, EPA, or DHA intake and suicide among Japanese men and women.

METHOD

Subjects were 47,351 men and 54,156 women aged 40-69 years who participated in the JPHC Study, completed a food frequency questionnaire in 1995-1999, and were followed for death through December 2005. We used the Cox proportional hazards regression model to estimate the hazard ratio (HR) and 95% confidence interval (CI) for suicide by quintile of intake.

RESULTS

A total of 213 and 85 deaths from suicide were recorded during 403,019 and 473,351 person-years of follow-up for men and women, respectively. Higher intakes of fish, EPA, or DHA were not associated with a lower risk of suicide. Multivariate HRs (95% CI) of suicide death for the highest versus lowest quintile of fish consumption were 0.95 (0.60-1.49) and 1.20 (0.58-2.47) for men and women, respectively. A significantly increased risk of suicidal death was observed among women with very low intake of fish, with HRs (95% CI) for those in 0-5th percentile versus middle quintile of 3.41 (1.36-8.51).

CONCLUSIONS

Our overall result does not support a protective role of higher intake of fish, EPA, or DHA against suicide in Japanese men and women.

Associations of smoking cessation with visceral fat area and prevalence of metabolic syndrome in men: the Hitachi health study

Weight gain after smoking cessation may deteriorate metabolic risk profiles, including that for metabolic syndrome. How risk profiles change according to the duration of smoking cessation and whether the visceral fat area (VFA) or the subcutaneous fat area (SFA) contributes to these changes remains uncertain. The subjects comprised 5,697 Japanese men who underwent an abdominal computed-tomography examination during a health check-up. Using never smokers as a reference group, the odds ratios of having metabolic syndrome and its components, defined using the National Cholesterol Education Program Adult Treatment Panel IIIcriteria, were calculated for each smoking category with adjustments for age, alcohol drinking, and physical activity (model 1) using a logistic regression analysis. Additional adjustments were also made for either VFA (model 2) or SFA (model 3). Current smokers had the lowest VFA (120.4 cm²) whereas ex-smokers (124.0-132.0 cm²) had a higher VFA than nonsmokers (123.1 cm²). Among the ex-smokers, VFA tended to decrease with increasing years of smoking cessation. In model 1, the odds ratios of having metabolic syndrome for current smokers and ex-smokers with smoking cessation for ≤ 4, 5-9, 10-14, and ≥ 15 years were 1.02, 1.33, 1.36, 1.40, and 1.09, respectively. The elevated odds ratios among ex-smokers (≤ 14 years) were reduced by 35-55.6% after further adjustment for VFA but not for SFA. Smoking cessation is associated with a deterioration of the metabolic risk profile, which can be ascribed, at least in part, to an increase in VFA not SFA.

Eating behavior in relation to prevalence of overweight among Japanese men

Obesity is an important risk factor for lifestyle diseases. There has been much interest in the role of eating behavior in the development of obesity, but findings from population-based epidemiologic studies are limited and inconsistent. The objective of our cross-sectional study was to examine the association between eating behavior and prevalence of overweight. Subjects were 290 men of two municipal offices in northeastern Kyusyu, Japan. A positive association was found between overweight and some eating behaviors; multivariate-adjusted odds ratios (95% confidence intervals) for overweight were 4.33 (2.46-7.64), 2.29 (1.22-4.32), and 2.01 (1.06-3.80) for the behaviors of eating quickly, eating until full and eating fatty foods, respectively. Moreover, the prevalence of overweight was further increased when these eating behaviors were combined; multivariate odds ratios (95% confidence intervals) of overweight for men with 1, 2 and ≥3 versus no high-risk eating behaviors were 2.66 (1.27-5.56), 4.32 (1.87-9.97) and 7.32 (3.01-17.84), respectively (pp<0.0001 for trend). Our findings suggest that eating quickly, eating until full and eating fatty foods are related to overweight in Japanese men.

Relations between waist circumference at four sites and metabolic risk factors

The location of waist circumference (WC) measurement differs among diagnostic guidelines for the metabolic syndrome. The present study examined which of four WC measurements was associated most strongly with the clustering of metabolic risk factors in cross-sectional study. The subjects comprised 1,140 Japanese employees, aged 20-70 years, who underwent health examinations in 2007 and 2008. WC was measured at (i) the narrowest part of the waist, (ii) midway between the lowest rib and the iliac crest, (iii) the umbilical level, and (iv) immediately above the iliac crest. A receiver operator characteristic (ROC) curve was used to assess the ability of each WC measurement to predict the presence of two or more other components of the metabolic syndrome, as defined by the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) in 2005. Multiple risk factors were seen in 43.0% of the men and 12.9% of the women. The minimum and maximum WC measurements differed by 3.9 cm among the men and 12.6 cm among the women. The areas under the curve examining the ability of the four WC measurements to predict the clustering of multiple risk factors were similar. If the same WC cutoff value was applied, the prevalence of the metabolic syndrome changed considerably according to the site of WC measurement. The four WC measurements had similar screening abilities. Given the differences in the WC values according to the site of measurement, WC must be measured at the site specified by each diagnostic guideline.

Associations of visceral and subcutaneous fat areas with the prevalence of metabolic risk factor clustering in 6,292 Japanese individuals: the Hitachi Health Study

OBJECTIVE

We examined the relationships of visceral fat area (VFA), subcutaneous fat area, and waist circumference, determined using computed tomography (CT), and BMI with metabolic risk factors in a large Japanese population.

RESEARCH DESIGN AND METHODS

Study subjects comprised 6,292 men and women who participated in the Hitachi Health Study and received CT examinations in 2007 and 2008.

RESULTS

Regarding the clustering of metabolic risk factors, the odds ratios (ORs) for the VFA quintiles were 1.0 (ref.), 2.4, 3.4, 5.0, and 9.7 for men and 1.0 (ref.), 1.5, 2.6, 4.6, and 10.0 for women (P < 0.001 for trends in both sexes). For the highest quintiles, the OR for VFA was 1.5 to 2 times higher than those of the other anthropometric indexes in both sexes.

CONCLUSIONS

We demonstrated a superior performance of VFA to predict the clustering of metabolic risk factors compared with other anthropometric indexes.