Association Between the Appendicular Extracellular-to-Intracellular Water Ratio and All-Cause Mortality: A 10-Year Longitudinal Study

The appendicular extracellular-to-intracellular water ratio (A-E/I) is a potential marker of skeletal muscle quality, reflecting the balance of water distribution between the extracellular and intracellular compartments of the appendicular limb regions. A-E/I has been increasingly used in recent studies; however, its association with adverse outcomes remains unclear. This study investigated the potential association between A-E/I and all-cause mortality. A prospective cohort study of 8 015 middle-aged and older adults (comprised of 4 755 women, aged 45-74 years) residing in a Japanese community was conducted. The baseline assessment was performed between 2010 and 2012, and the follow-up period lasted until July 2022. A-E/I and skeletal muscle mass were measured using segmental bioelectrical impedance spectroscopy. Handgrip strength (HGS) was measured using a Smedley-type dynamometer. Lifestyle, medical history, and physical activity were assessed by questionnaire and accelerometer. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for each quartile (Q) of A-E/I were estimated using the multivariable Cox regression model. During a 10.5-year median follow-up, the mortality rates were 8.9 and 3.6 per 1 000 person-years for men (292 deaths) and women (174 deaths), respectively. A-E/I quartiles were positively associated with all-cause mortality in both sexes (men: Q1, HR: 1.0 [95% CI: reference], Q4, HR: 1.8 [1.1-2.9], ptrend < .05; women, Q4, HR: 2.2 [1.3-3.8], ptrend < .01). This association remained significant after further adjustment for skeletal muscle mass and HGS (ptrend < .05). Our findings suggest that A-E/I serves as an early predictive marker for mortality in middle-aged and older Japanese adults.

Association of appendicular extracellular-to-intracellular water ratio with age, muscle strength, and physical activity in 8,018 community-dwelling middle-aged and older adults

BACKGROUND

The appendicular extracellular-to-intracellular water ratio (Ap ECW/ICW) has recently gained attention as a non-invasive measurable marker of muscle quality. However, there is a lack of basic evidence regarding age-related changes, sex differences, contribution to muscle strength independent of skeletal muscle mass (SMM), and potential improvement through physical activity (PA) in Ap ECW/ICW.

METHODS

This cross-sectional study enrolled 8,018 middle-aged and older Japanese individuals (aged 45-75 years). The Ap ECW/ICW and SMM were measured using segmental bioelectrical impedance spectroscopy. Muscle strength was evaluated by measuring the handgrip strength (HGS) with a dynamometer, and the PA level (PAL) was measured with an accelerometer. We performed a linear regression analysis of the associations of the Ap ECW/ICW with age, HGS, and PAL.

RESULTS

The Ap ECW/ICW increased by 0.019 for men and 0.014 for women per 5-year increase in age (p < 0.001), and the age-related increase was greater in men than in women (p for interaction <0.001). The Ap ECW/ICW was more strongly associated with the HGS than with the SMM in both men and women (p < 0.001). PAL showed a significant inverse association with the Ap ECW/ICW in both men and women (p < 0.001).

CONCLUSIONS

Ap ECW/ICW is higher with age, and it varies by sex. The Ap ECW/ICW may reflect muscle strength more than the SMM, suggesting that the Ap ECW/ICW may be improved by PA. The findings from this study may provide a framework for further Ap ECW/ICW research.

Dose-response relationship between daily step count and prevalence of sarcopenia: A cross-sectional study

OBJECTIVES

Daily step counts are an easy-to-understand indicator of physical activity; however, there is limited evidence regarding the optimal daily step count to prevent sarcopenia. This study examined the dose-response relationship between daily step count and the prevalence of sarcopenia and explored the optimal dose.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

The study included 7949 community-dwelling middle-aged and older adults (aged 45-74 years) from Japan.

MEASUREMENTS

Skeletal muscle mass (SMM) was assessed using bioelectrical impedance spectroscopy, and muscle strength was quantified through handgrip strength (HGS) measurement. Participants who exhibited both low HGS (men: <28 kg, women: <18 kg) and low SMM (lowest quartile in each sex-specific category) were defined as having sarcopenia. Daily step counts were measured for 10 days using a waist-mounted accelerometer. To examine the association between daily step count and sarcopenia, a multivariate logistic regression analysis was performed, adjusting for potential confounding factors such as age, sex, body mass index, smoking status, alcohol consumption, protein intake, and medical history. The odds ratios (ORs) and confidence intervals (CIs) were calculated based on the daily step counts categorized into quartiles (Q1-Q4). Finally, a restricted cubic spline curve was fitted to further investigate the dose-response relationship between daily step count and sarcopenia.

RESULTS

The prevalence of sarcopenia in the overall participants was 3.3 % (259/7949 participants), with a mean daily step count of 7292 ± 2966 steps. Expressed in quartiles, the mean daily step counts were 3873 ± 935 steps in Q1, 6025 ± 503 steps in Q2, 7942 ± 624 steps in Q3, and 11,328 ± 1912 steps in Q4. The prevalence of sarcopenia in each quartile of daily step count was 4.7 % (93/1987 participants) in Q1, 3.4 % (68/1987 participants) in Q2, 2.7 % (53/1988 participants) in Q3, and 2.3 % (45/1987 participants) in Q4. The ORs and 95 % CIs adjusted for covariates demonstrated a statistically significant inverse association between daily step count and sarcopenia prevalence (P for trend <0.01), as follows: Q1, reference; Q2, 0.79 (95 % CI: 0.55-1.11); Q3, 0.71 (95 % CI: 0.49-1.03); Q4, 0.61 (95 % CI: 0.41-0.90). The restricted cubic spline curve indicated that the ORs leveled off at approximately 8000 steps per day, and no statistically significant decrease in ORs was observed for daily step counts above this threshold.

CONCLUSIONS

The study found a significant inverse association between daily step count and the prevalence of sarcopenia, with the association plateauing when the daily step count exceeded approximately 8000 steps. These findings suggest that 8000 steps per day may be the optimal dose to prevent sarcopenia. Further intervention and longitudinal studies are needed to validate the results.

Sedentary time, physical activity, and serum SPARC in a middle-aged population

The influence of habitual physical activity (PA) on the circulating levels of secreted protein acidic and rich in cysteine (SPARC) remains unclear. The purpose of the current study was to clarify the effects of sedentary time, light-intensity PA (LPA), and moderate- to vigorous-intensity PA (MVPA) on the serum SPARC in a general middle-aged population. The current study is a cross-sectional study of 4,000 men and 6,040 women (40-69 years). Sedentary time, LPA, and MVPA were objectively measured by an accelerometer. The serum SPARC concentration was measured by enzyme-linked immunosorbent assay. Using an isotemporal substitution model, cross-sectional associations of replacing sedentary time with either LPA or MVPA on serum SPARC levels were analysed according to sex. Interactions with subject characteristics, such as the body mass index (BMI), smoking, and alcohol consumption, were also examined. In men, replacing 60 min of sedentary time with 60 min of MVPA was significantly associated with 23 ng/mL lower serum SPARC levels (confidence interval: -43, -2) after adjusting for confounders, including the BMI (P = 0.028). A significant interaction between replacing sedentary behaviour with LPA and the BMI on SPARC was detected in women (P = 0.029), although the stratified associations for each BMI level (<25 or ≥25 kg/m²) did not reach significance. The current study suggests that replacing sedentary time with MVPA is associated with reduced serum SPARC levels in middle-aged men, but not in women. In addition, a potential interaction between LPA and the BMI on SPARC was also found in women.

83Replacing sedentary time with moderate-to-vigorous physical activity is associated with decreased serum SPARC in men

Background

Secreted protein acidic and rich in cysteine (SPARC) may play a role in the prevention of colon cancer through exercise, while SPARC is considered as a promoter of insulin resistance. The purpose of the present study was to clarify the effects of replacing sedentary time with either light-intensity PA (LPA) or moderate- to vigorous-intensity PA (MVPA) on serum SPARC in a general population.

Methods

The study subjects were 4000 men and 6040 women (40 to 69 years) who participated in baseline surveys of a population-based cohort study. Sedentary time, LPA, and MVPA were objectively measured by an accelerometer. The serum SPARC concentration was measured by an enzyme-linked immunosorbent assay. Using an isotemporal substitution model, cross-sectional associations of replacing sedentary time with either LPA or MVPA on serum SPARC levels were analyzed according to sex. Adjustment was made for potential confounding factors.

Results

In men, replacing 60 min of sedentary time with 60 min of MVPA was associated with 23 ng/mL (confidence interval -43, -2) lower serum SPARC levels even after adjusting for confounders, including the BMI (P = 0.028), while no such association was observed for LPA. Furthermore, no such significant replacement effects were observed in women.

Conclusions

The current study showed that replacing sedentary time with MVPA results in reduced serum SPARC concentrations in men.

Key messages

Effect of habitual PA to decrease circulating SPARC is PA intensity-specific.

Association between habitual coffee consumption and skeletal muscle mass in middle-aged and older Japanese people

AIMS

Coffee consumption has been suggested, in animal studies, to inhibit the progression of sarcopenia, possibly through its anti-inflammatory effects; however, few studies have been carried out in humans. We aimed to examine whether coffee consumption was related to indicators of sarcopenia in a Japanese population, and whether the association was mediated by reduced inflammation.

METHODS

This study was a cross-sectional design. Participants were community residents (n = 6369) aged 45-74 years. We measured skeletal muscle mass index (SMI; kg/m² ) by a bioelectrical impedance method, and grip strength with a Smedley-type dynamometer. Habitual coffee consumption was assessed by a self-administered questionnaire. Serum high-sensitivity C-reactive protein was measured as an inflammatory marker. The association between habitual coffee consumption and SMI or grip strength was analyzed with a linear regression model adjusted for covariates.

RESULTS

A significant positive association was found between coffee consumption and SMI (men: β = 0.023; P_trend  = 0.004, women: β = 0.011; P_trend  = 0.012). Further adjustment for high-sensitivity C-reactive protein did not materially alter the results (men: β = 0.023; P_trend  = 0.005, women: β = 0.009; P_trend  = 0.024). The relationship between coffee consumption and grip strength did not reach statistical significance; however, a positive trend was observed (men: β = 0.208; P_trend  = 0.085, women: β = 0.092; P_trend  = 0.167).

CONCLUSIONS

We found that coffee consumption was positively associated with SMI independently of inflammation in middle-aged and older Japanese people. Reduced inflammation by coffee does not seem to be an important mediator, and further investigations are required to explore the mechanisms of this association. Geriatr Gerontol Int 2021; 21: 950-958.

Perceived stress, depressive symptoms, and cortisol-to-cortisone ratio in spot urine in 6878 older adults

BACKGROUND

Late life depression and perceived stress could influence disease pathways via reduced 11β-HSD2 activity, particularly given suggestions that reduced 11β-HSD2 activity, which is reflected in the cortisol-to-cortisone ratio, is a risk factor of disease. To date, however, examination of the relationship between the cortisol-to-cortisone ratio and perceived stress or depressive symptoms is insufficient.

METHODS

We examined the cross-sectional association of the cortisol-to-cortisone ratio with perceived stress and depressive symptoms, and analyzed whether cortisol levels modify this association, in 6878 participants aged 45-74 years. Cortisol and cortisone in spot urine were measured using liquid chromatography-mass spectrometry. Perceived stress during the past year was measured using a self-reported questionnaire. Depressive symptoms were evaluated using the Zung Self-Rating Depression Scale. Analyses were performed with adjustment for age, sex, lifestyle factors (smoking habit, alcohol consumption, physical activity, and sleeping hours), and physical health factors (body mass index [kg/m²] and medical history [diabetes, hypertension, and medication for hyperlipidemia or corticosteroids]).

RESULTS

Cortisol-to-cortisone ratio and cortisol were positively associated with perceived stress (% change: 2.33, P_trend = 0.003; and 4.74, P_trend = 0.001, respectively), but were not significantly associated with depressive symptoms. Further, the relationship between cortisol-to-cortisone ratio and perceived stress was modified by cortisol level and sex: the positive association between perceived stress and the cortisol-to-cortisone ratio was more evident in subjects with lower cortisol levels (P_interaction = 0.009) and in men (P_interaction = 0.026).

CONCLUSIONS

These findings suggest that the cortisol-to-cortisone ratio in spot urine may be a useful marker for non-acute perceived stress in daily life against a possible background of reduced 11β-HSD2 in older adults.

The interaction between mitochondrial haplogroups (M7a/D) and physical activity on adiponectin in a Japanese population

Mitochondrial haplogroups F, A, and M7a are associated with increased risks of lifestyle diseases, while haplogroups N9 and D are associated with decreased risks of lifestyle diseases or with longevity. The current study determined the existence of interactions between 5 selected haplogroups and physical activity (PA) on total and high-molecular-weight (HMW) adiponectin in 3,994 men and 6,014 women. The interactions between haplogroups (M7a/D) and PA on adiponectin were significant in men (total and HMW: P-interaction = 0.041 and 0.011). The positive association of PA with adiponectin in men carrying haplogroup M7a is attenuated in comparison to men carrying haplogroup D.

Habitual Light-intensity Physical Activity and ASC Methylation in a Middle-aged Population

Apoptosis-associated, speck-like protein containing a caspase recruitment domain (ASC) plays an important role in inflammatory cytokine synthesis in peripheral blood mononuclear cells (PBMCs), and the expression of ASC is suppressed by increased methylation of its CpG sites. The current study investigated the longitudinal association of replacing sedentary time with light-intensity physical activity (LPA) or moderate to vigorous-intensity physical activity (MVPA) on the ASC methylation in middle-aged people. We investigated 1 238 individuals who participated in baseline and 5-year follow-up surveys of a population-based cohort study. Sedentary, LPA and MVPA time were objectively measured using accelerometers. ASC methylation in PBMCs was measured by pyrosequencing. Using a multiple linear regression and employing an isotemporal substitution model, the longitudinal associations of changes in the sedentary time, LPA and MVPA on the changes in the ASC methylation were analyzed after adjusting for potential confounders. Substituting 60 min per day of LPA for sedentary time was associated with 1.17 times (95% confidence interval 1.07, 1.27) higher ASC methylation levels (mean of 7 CpG sites, P<0.001). However, such effects were not seen for MVPA. These results suggest that substituting LPA for sedentary time may be linked with increased (favorable) ASC methylation as a potential biomarker of systemic inflammation.

Intensity-Specific and Modified Effects of Physical Activity on Serum Adiponectin in a Middle-Aged Population

Context

The effects of intensity-specific physical activity (PA) and its interaction with other lifestyle factors on serum adiponectin are currently unclear.

Objective

To investigate the effects of replacing sedentary time with either light-intensity PA (LPA) or moderate- to vigorous-intensity PA (MVPA) on total and high-molecular-weight (HMW) adiponectin and to examine interactions with smoking, alcohol drinking, coffee consumption, and menopausal status in a general population.

Design/Setting

Cross-sectional study of 4013 men and 6050 women (40 to 69 years of age).

Main Outcome Measures

The associations of replacing sedentary time with LPA or MVPA on total and HMW adiponectin were analyzed using an isotemporal substitution model.

Results

In men, reallocating 60 minutes of sedentary time to 60 minutes of LPA was associated with 9% and 13% higher total and HMW adiponectin levels even after adjusting for confounders, although such associations were not observed for MVPA. A similar pattern of results was also seen in women. The effect of replacing sedentary time with LPA on adiponectin was clearer in middle/high coffee consumers than in low coffee consumers among women. Although increasing the effect of replacing sedentary time with MVPA on adiponectin was clearer in former/current smokers than in never smokers among men, the replacement effect for MVPA on total adiponectin was clearer in premenopausal women than in postmenopausal women.

Conclusions

Replacing sedentary time with LPA resulted in increased levels of total and HMW adiponectin. The replacement effects for LPA or MVPA were found to be multiply modified by smoking, coffee consumption, and menopausal status.

Coping strategy and social support modify the association between perceived stress and C-reactive protein: a longitudinal study of healthy men and women

Inconsistent associations have been reported between perceived stress and C-reactive protein (CRP), a marker of systemic inflammation. We previously observed a male-specific inverse relationship between perceived stress and CRP in a cross-sectional study. In the present study, we examined the longitudinal association between changes in perceived stress and CRP, and further analyzed whether changes in coping strategies and social support modify this association. This study included 8454 participants in both a baseline survey and a follow-up survey 5 years later. Psychosocial measures (i.e. perceived stress, coping strategies, and social support) and CRP concentrations were measured by identical means in both surveys. Consistent with our previous findings, increased perceived stress was significantly associated with lower CRP in men (p_trend = .037), but not in women. Increased "emotional expression," a coping strategy, was also associated with lower CRP in women (p_trend = .024). Furthermore, interactions between perceived stress and a coping strategy (positive reappraisal) or social support on CRP were found in men (p_interaction = .007 and .038, respectively); the above inverse association between stress and CRP was not detected for participants with diminished positive reappraisal or social support. In conclusion, increases in perceived stress during a 5-year period were associated with decreases in CRP among healthy men, and the observed association was possibly modified by coping strategy or social support.

Analysis of White Matter Damage in Patients with Multiple Sclerosis via a Novel In Vivo MR Method for Measuring Myelin, Axons, and G-Ratio

BACKGROUND AND PURPOSE

Myelin and axon volume fractions can now be estimated via MR imaging in vivo, as can the g-ratio, which equals the ratio of the inner to the outer diameter of a nerve fiber. The purpose of this study was to evaluate WM damage in patients with MS via this novel MR imaging technique.

MATERIALS AND METHODS

Twenty patients with relapsing-remitting MS with a combined total of 149 chronic plaques were analyzed. Myelin volume fraction was calculated based on simultaneous tissue relaxometry. Intracellular and CSF compartment volume fractions were quantified via neurite orientation dispersion and density imaging. Axon volume fraction and g-ratio were calculated by combining these measurements. Myelin and axon volume fractions and g-ratio were measured in plaques, periplaque WM, and normal-appearing WM.

RESULTS

All metrics differed significantly across the 3 groups (P < .001, except P = .027 for g-ratio between periplaque WM and normal-appearing WM). Those in plaques differed most from those in normal-appearing WM. The percentage changes in plaque and periplaque WM metrics relative to normal-appearing WM were significantly larger in absolute value for myelin volume fraction than for axon volume fraction and g-ratio (P < .001, except P = .033 in periplaque WM relative to normal-appearing WM for comparison between myelin and axon volume fraction).

CONCLUSIONS

In this in vivo MR imaging study, the myelin of WM was more damaged than axons in plaques and periplaque WM of patients with MS. Myelin and axon volume fractions and g-ratio may potentially be useful for evaluating WM damage in patients with MS.

Intensity-specific effect of physical activity on urinary levels of 8-hydroxydeoxyguanosine in middle-aged Japanese

Physical activity (PA) is recommended to both promote and maintain health and prevent cancer by improving the body's DNA repair system, which is considered a mechanism of cancer prevention. However, associations between PA and urinary levels of 8-hydroxydeoxyguanosine (8-OH-dG), which reflects DNA damage, are unclear. This cross-sectional study included 2370 men and 4052 women aged 45-74 years enrolled between 2010 and 2012. Habitual PA was assessed by single-axis accelerometer and urinary 8-OH-dG levels by automated HPLC. Multiple linear regression analysis was used to examine the relationship between log-transformed urinary 8-OH-dG and total PA (TPA) and PA of moderate/vigorous intensity (MVPA; ≥3 metabolic equivalents), with adjustment for age, body mass index, energy intake, alcohol consumption, smoking status, daily coffee drinking, menopause status (in women), and TPA (for MVPA). On multivariate adjustment, urinary 8-OH-dG levels were inversely correlated with TPA (β = -0.020, P < 0.01) in women, and this correlation was not changed by PA intensity. Conversely, urinary 8-OH-dG levels were inversely correlated with MVPA (β = -0.022, P < 0.05) in men, although the correlation with TPA was non-significant. This inverse correlation was clearer in current smokers than in never or former smokers, although the interaction between smoking status and MVPA on urinary 8-OH-dG levels was non-significant. In conclusion, greater TPA in women and greater MVPA in men were correlated with reduction in urinary 8-OH-dG, suggesting sex-specific effects of MVPA and TPA on protection from oxidative DNA damage. Increasing PA may mediate reduction in oxidative stress.

Dietary patterns and serum gamma-glutamyl transferase in Japanese men and women

Background

Although specific foods and nutrients have been examined as potential determinants of serum gamma-glutamyl transferase (GGT) concentrations, the relationship between dietary patterns and GGT remains unknown. The present cross-sectional study aimed to determine relationships between dietary patterns and GGT concentrations, and the effects of lifestyle factors on GGT.

Methods

Relationships between dietary patterns and GGT were analyzed in 9803 Japanese individuals (3723 men and 6080 women age 40–69 years) without a history of liver diseases or elevated serum aminotransferase. We examined major dietary patterns by factor analysis of 46 items determined from a validated, short food frequency questionnaire.

Results

We defined dietary patterns as healthy, Western, seafood, bread, and dessert. The healthy pattern was inversely related to GGT in men (odds ratio [OR] for highest vs lowest quartile, 0.72; 95% confidence interval [CI], 0.57–0.92; P < 0.01 for trend) and women (OR 0.82; 95% CI, 0.66–1.0; P = 0.05 for trend), whereas the seafood pattern was positively related to GGT in men (OR 1.27; 95% CI, 1.01–1.61; P = 0.03 for trend) and women (OR 1.21; 95% CI, 0.98–1.49; P = 0.05 for trend). Male-specific inverse associations with GGT were found for bread and dessert patterns (OR 0.63; 95% CI, 0.50–0.80 and OR 0.53; 95% CI, 0.41–0.68, respectively; P < 0.01 for both trends). Seafood or bread patterns and alcohol consumption significantly interacted with GGT in men (P = 0.03 and <0.01 for interaction, respectively) and between the dessert pattern and body mass index or smoking habit in women (P = 0.03 and <0.01, respectively, for interaction).

Conclusions

Dietary patterns may be important determinants of GGT, and their possible clinical implications warrant further investigation.

Perceived stress and coping strategies in relation to body mass index: cross-sectional study of 12,045 Japanese men and women

Background

Accumulated evidence suggests a weak positive relationship between psychosocial stress and body mass index (BMI), but little is known about stress coping strategies and BMI.

Objective

We aimed to examine if perceived stress and coping strategies are related to BMI, with any of their mutual interactions on BMI.

Methods

This cross-sectional study included 5,063 men and 6,982 women aged 40-69 years. A self-administered questionnaire ascertained perceived stress and 5 items of coping strategies (emotion expression, emotional support seeking, positive reappraisal, problem solving, and disengagement). Analyses were performed by gender with adjustment for age, socioeconomic status, and lifestyle factors.

Results

No significant associations were detected between perceived stress and BMI in either men (P_trend = 0.09) or women (P_trend = 0.58). In men, however, ‘disengagement’ showed an inverse association with BMI (P_trend < 0.001), and ‘positive reappraisal’ and ‘problem solving’ revealed a positive association with BMI (P_trend = 0.04 and 0.007, respectively) even after controlling for perceived stress. A possible interaction between perceived stress and ‘disengagement’ on BMI was found in men (P_interaction = 0.027); the inverse association between ‘disengagement’ and BMI was more evident in higher levels of stress (β = −0.13, P_trend = 0.21 in low; β = −0.22, P_trend = 0.01 in medium; and β = −0.24, P_trend = 0.06 in high). In men, ‘disengagement’ was inversely associated with overweight/obesity (odds ratio 0.79, 95% confidential interval 0.67-0.95), and “positive reappraisal” was positively associated with it (1.25, 1.02-1.54).

Conclusions

Coping strategies may have an important role in developing overweight/obesity, particularly in men.

Association between the PPARGC1A polymorphism and aerobic capacity in Japanese middle-aged men

OBJECTIVE

A lower frequency for the peroxisome proliferator-activated receptor γ coactivator 1α (PPARGC1A) Ser482 allele has been reported in elite-level endurance athletes among Caucasians, although this gene polymorphism has not been found to be associated with aerobic capacity in German, Dutch or Chinese populations. The purpose of the current study was to examine the associations between the Gly482Ser polymorphism and aerobic fitness in 112 Japanese middle-aged men.

METHODS

The PPARGC1A Gly482Ser polymorphism was identified according to a TaqMan(®) SNP genotyping assay. Habitual physical activity was objectively measured using an accelerometer. The lactate threshold (LT), an index of aerobic fitness, was measured based on a submaximal graded exercise test performed on an electric cycle ergometer. The association between the LT and the Gly482Ser polymorphism was assessed according to a multiple regression analysis and analysis of covariance, with adjustment for potential confounders (age, body mass index, cigarette smoking, physical activity level and regular exercise).

RESULTS

A significant association was observed between the PPARGC1A Gly482Ser polymorphism and LT, as carriers of the Ser482 had higher LT values than the Gly482 carriers.

CONCLUSION

The current results suggest that the PPARGC1A Ser482 allele is associated with a higher aerobic capacity in Japanese middle-aged men.

Factors associated with non-participation in a face-to-face second survey conducted 5 years after the baseline survey

Background

Non-participation in second surveys is reported to be associated with certain baseline characteristics; however, such data are unavailable for Japanese populations. Although disease incidence during follow-up might influence participation, few reports have addressed this possibility. This study sought to identify factors associated with non-participation in a second survey of a population-based cohort, and to evaluate the influence of self-reported disease incidence on non-participation.

Methods

After excluding participants who left the area (n = 423), died (n = 163), and withdrew from the study (n = 9) among 12 078 participants in a baseline survey for the Japan Multi-Institutional Collaborative Cohort Study in the Saga region between 2005 and 2007, 11 483 people were invited by mail to participate in a face-to-face second survey between 2010 and 2012. The 5-year clinical health history of non-participants was assessed by mail or telephone. Baseline characteristics and self-reported clinical outcomes of non-participants were compared with those of participants.

Results

Among 11 483 people, 8454 (73.6%) participated in the second survey, and 2608 out of 3029 non-participants answered mail or telephone health surveys. Female sex, youngest and oldest ages, lower education, lower occupational class, current smoking, lower physical activity level, shorter sleep time, obesity, and constipation were associated with non-participation. Light drinking (0.1–22.9 g ethanol/day) was associated with participation. Non-participants reported a significantly higher incidence of cancer and a significantly lower proportion of hypertension compared with participants.

Conclusions

Both baseline characteristics and disease incidence during the follow-up period had significant associations with non-participation in the face-to-face second survey.

Polymorphisms of genes involved in lipid metabolism and risk of chronic kidney disease in Japanese - cross-sectional data from the J-MICC study

BACKGROUND

Chronic kidney disease (CKD) is known to be one of the causes of cardiovascular disease and end-stage renal disease. Among the several treatable risk factors of CKD, that of dyslipidemia is relatively controversial. To clarify the association of polymorphisms in genes involved in lipid metabolism with the risk of CKD in the Japanese population, we used cross-sectional data from the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study.

METHODS

A total of 3,268 men and women, aged 35-69 years, were selected from J-MICC Study participants for inclusion in this study. Twenty-eight candidate single nucleotide polymorphisms (SNPs) were selected in 17 genes associated with the risk of lipid metabolism disorders, and genotyping of the subjects was conducted using the multiplex PCR-based invader assay. The prevalence of CKD was determined for stages 3-5 (defined as estimated glomerular filtration rate <60 ml/min/1.73 m2).

RESULTS

Logistic regression analysis revealed that SNPs APOA5 T - 1131C (rs662799), APOA5 T1259C (rs2266788), TOMM40 A/G (rs157580), and CETP TaqIB (rs708272) were significantly associated with CKD risk in those individuals genotyped, with age- and sex-adjusted odds ratios (ORs) per minor allele (and 95% confidence intervals (CIs)) of OR 1.22 (95% CI: 1.06-1.39), 1.19 (1.03-1.37), 1.27 (1.12-1.45), and 0.81 (0.71-0.92), respectively. Analysis of the gene-environment interaction revealed that body mass index (BMI) was a significant effect modifier for APOA5 T - 1131C (rs662799) and a marginally significant effect modifier for APOA5 T/C (rs2266788), with the interaction between BMI ≥30 and individuals with at least one minor allele of each genotype of OR 10.43 (95% CI: 1.29-84.19) and 3.36 (0.87-13.01), respectively.

CONCLUSIONS

Four polymorphisms in APOA5, TOMM40, and CETP were shown to be significantly associated with CKD risk, and a significant interaction between the two APOA5 SNPs and BMI on CKD risk was also demonstrated. This suggests the future possibility of personalized risk estimation for this life-limiting disease.

Identification of hemiclonal reproduction in three species of Hexagrammos marine reef fishes

Natural hybrids between the boreal species Hexagrammos octogrammus and two temperate species Hexagrammos agrammus and Hexagrammos otakii were observed frequently in southern Hokkaido, Japan. Previous studies revealed that H. octogrammus is a maternal ancestor of both hybrids; the hybrids are all fertile females and they frequently breed with paternal species. Although such rampant hybridization occurs, species boundaries have been maintained in the hybrid zone. Possible explanations for the absence of introgressions, despite the frequent backcrossing, might include clonal reproduction: parthenogenesis, gynogenesis and hybridogenesis. The natural hybrids produced haploid eggs that contained only the H. octogrammus genome (maternal ancestor) with discarded paternal genome and generated F1 -hybrid type offspring by fertilization with the haploid sperm of H. agrammus or H. otakii (paternal ancestor). This reproductive mode was found in an artificial backcross hybrid between the natural hybrid and a male of the paternal ancestor. These findings indicate that the natural hybrids adopt hybridogenesis with high possibility and produce successive generations through hybridogenesis by backcrossing with the paternal ancestor. These hybrids of Hexagrammos represent the first hybridogenetic system found from marine fishes that widely inhabit the North Pacific Ocean. In contrast with other hybridogenetic systems, these Hexagrammos hybrids coexist with all three ancestral species in the hybrid zone. The coexistence mechanism is also discussed.

Objectively measured physical activity and inflammatory cytokine levels in middle-aged Japanese people

OBJECTIVE

Studies using self-reported physical activity (PA) showed that higher PA is associated with lower circulating levels of C-reactive protein; in contrast, studies investigating associations of objective PA and other inflammatory markers are limited. We investigated cross-sectional associations of accelerometer-determined PA with circulating levels of myokine-type inflammatory cytokines in a middle-aged Japanese population.

METHOD

A total of 1838 individuals (737 men and 1101 women) aged 40 to 69 years participated in the baseline survey of a population-based cohort study in Saga, Japan (2005-2007). Habitual PA was assessed by a single-axis accelerometer. Serum interleukin (IL)-4, IL-6, IL-8, IL-15, and tumor necrosis factor (TNF)-α were measured by a multiplex enzyme-linked immunosorbent assay. Associations between PA and cytokine levels were assessed by multiple regression analysis and analysis of covariance, with adjustment for potential confounders.

RESULTS

Step count and PA level (PAL) were inversely associated with TNF-α and IL-15 even after adjusting for BMI. Similarly, greater PA indices were also independently associated with a lower level of inflammatory cytokine z score as an index of overall inflammation.

CONCLUSION

The current results suggest that greater engagement in daily PA may be linked with reduced levels of myokine-type cytokines including IL-15, irrespective of body weight in middle-aged Japanese people.

Immunogenicity and safety after booster vaccination of diphtheria, tetanus, and acellular pertussis in young adults: an open randomized controlled trial in Japan

The recent increase of pertussis in young adults in Japan is hypothesized to be due in part to waning protection from the acellular pertussis vaccine. While a booster immunization may prevent an epidemic of pertussis among these young adults, little is known about the safety and immunogenicity of such a booster with the diphtheria, tetanus, and acellular pertussis vaccine (DTaP), which is currently available in Japan. One hundred and eleven medical students with a mean age of 19.4 years were randomly divided into 2 groups of 55 and 56 subjects and received, respectively, 0.2 or 0.5 ml of DTaP. Immunogenicity was assessed by performing the immunoassay using serum, and the geometric mean concentration (GMC), GMC ratio (GMCR), seropositive rate, and booster response rate were calculated. Adverse reactions and adverse events were monitored for 7 days after vaccination. After booster vaccination in the two groups, significant increases were found in the antibodies against pertussis toxin, filamentous hemagglutinin, diphtheria toxoid, and tetanus toxoid, and the booster response rates for all subjects reached 100%. The GMCs and GMCRs against all antigens were significantly higher in the 0.5-ml group than in the 0.2-ml group. No serious adverse events were observed. Frequencies of local reactions were similar in the 2 groups, although the frequency of severe local swelling was significantly higher in the 0.5-ml group. These data support the acceptability of booster immunization using both 0.2 and 0.5 ml of DTaP for young adults for controlling pertussis. (This study was registered at UMIN-CTR under registration number UMIN000010672.).

Detailed analysis of Japanese population substructure with a focus on the southwest islands of Japan

Uncovering population structure is important for properly conducting association studies and for examining the demographic history of a population. Here, we examined the Japanese population substructure using data from the Japan Multi-Institutional Collaborative Cohort (J-MICC), which covers all but the northern region of Japan. Using 222 autosomal loci from 4502 subjects, we investigated population substructure by estimating F_ST among populations, testing population differentiation, and performing principal component analysis (PCA) and correspondence analysis (CA). All analyses revealed a low but significant differentiation between the Amami Islanders and the mainland Japanese population. Furthermore, we examined the genetic differentiation between the mainland population, Amami Islanders and Okinawa Islanders using six loci included in both the Pan-Asian SNP (PASNP) consortium data and the J-MICC data. This analysis revealed that the Amami and Okinawa Islanders were differentiated from the mainland population. In conclusion, we revealed a low but significant level of genetic differentiation between the mainland population and populations in or to the south of the Amami Islands, although genetic variation between both populations might be clinal. Therefore, the possibility of population stratification must be considered when enrolling the islander population of this area, such as in the J-MICC study.

Profile of participants and genotype distributions of 108 polymorphisms in a cross-sectional study of associations of genotypes with lifestyle and clinical factors: a project in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study

Background

Most diseases are thought to arise from interactions between environmental factors and the host genotype. To detect gene–environment interactions in the development of lifestyle-related diseases, and especially cancer, the Japan Multi-institutional Collaborative Cohort (J-MICC) Study was launched in 2005.

Methods

We initiated a cross-sectional study to examine associations of genotypes with lifestyle and clinical factors, as assessed by questionnaires and medical examinations. The 4519 subjects were selected from among participants in the J-MICC Study in 10 areas throughout Japan. In total, 108 polymorphisms were chosen and genotyped using the Invader assay.

Results

The study group comprised 2124 men and 2395 women with a mean age of 55.8 ± 8.9 years (range, 35–69 years) at baseline. Among the 108 polymorphisms examined, 4 were not polymorphic in our study population. Among the remaining 104 polymorphisms, most variations were common (minor allele frequency ≥0.05 for 96 polymorphisms). The allele frequencies in this population were comparable with those in the HapMap-JPT data set for 45 Japanese from Tokyo. Only 5 of 88 polymorphisms showed allele-frequency differences greater than 0.1. Of the 108 polymorphisms, 32 showed a highly significant difference in minor allele frequency among the study areas (P < 0.001).

Conclusions

This comprehensive data collection on lifestyle and clinical factors will be useful for elucidating gene–environment interactions. In addition, it is likely to be an informative reference tool, as free access to genotype data for a large Japanese population is not readily available.

Association between dietary pattern and serum C-reactive protein in Japanese men and women

BACKGROUND

Dietary pattern may influence the risks of cardiovascular disease, atherosclerosis, type 2 diabetes, and metabolic syndrome through its effects on inflammation. We evaluated the association between dietary pattern and serum high-sensitivity C-reactive protein (hs-CRP) in a Japanese population.

METHODS

In this cross-sectional analysis, we used baseline data from 3905 men and 5640 women (age 40-69 years) who participated in a population-based cohort study between November 2005 and December 2007. Participants with possible inflammation-related diseases, current analgesic use, high hs-CRP levels (≥3000 ng/mL) or extreme dietary energy intake were excluded. We used 46 items from a validated short food frequency questionnaire and examined major dietary patterns by factor analysis.

RESULTS

We identified 5 dietary patterns: healthy (high in vegetables and fruit), Western (high in meat and fried foods), seafood (high in shellfish, squid, fish, etc.), bread (high in bread and low in rice), and dessert (high in confections and fruit). After adjustment for age, alcohol use, smoking, physical activity, and body mass index, hs-CRP levels in men were inversely associated with the healthy, bread, and dessert patterns (P-trend: 0.01, 0.06, and <0.01, respectively) and positively associated with the seafood pattern (P-trend = 0.02). In women, hs-CRP levels were inversely associated with the healthy pattern (P-trend = 0.06) and positively associated with the Western pattern (P-trend = 0.06).

CONCLUSIONS

The healthy dietary pattern may be associated with suppressed inflammation in Japanese men and women, independently of body mass index and other factors. The sex-specific associations of hs-CRP with other dietary patterns (eg, the seafood pattern) require further study.

Optimal cutoff values of waist circumference and the discriminatory performance of other anthropometric indices to detect the clustering of cardiovascular risk factors for metabolic syndrome in Japanese men and women

OBJECTIVE

To evaluate the pertinent cutoffs of waist circumference (WC) and the discriminatory performance of other anthropometric indices to detect clustering cardiovascular risk factors for metabolic syndrome (MetS) in Japan, where the current WC cutoffs for MetS (85 cm for men and 90 cm for women) remain controversial.

METHODS

We analyzed the baseline data from 844 subjects (330 men and 514 women) aged 40-69 years who participated in a cohort study in Saga city, Japan, between November 2005 and December 2007. Receiver operating characteristic (ROC) analyses were performed to find an appropriate cutoff (defined as the point nearest to the upper left corner of the ROC curve) of each anthropometric index for the presence of multiple risk factors among dyslipidemia, hypertension, and hyperglycemia [which was defined as hemoglobin A1c (HbA1c) levels at and above 5.2, 5.5, or 5.8%, values approximately corresponding to fasting plasma glucose levels of 100, 110, and 120 mg/dL, respectively].

RESULTS

The optimal WC cutoff was 88 cm (sensitivity 60%, specificity 70%) for men and 82 cm (sensitivity 78%, specificity 62%) for women; changing the HbA1c cutoff affected the results in women only (~85 cm). For the currently defined WC cutoffs in Japan, specificity was low (53-57%) in men, whereas sensitivity was very low (32-42%) in women. Body mass index, proportion of body fat, waist-to-height ratio, and waist-to-hip ratio showed area under the curve values similar to that of WC.

CONCLUSION

The current Japanese criteria of WC for MetS may be low for men and too high and insensitive for women in our study population. Other anthropometric indices such as waist-to-height ratio did not confer an improved discriminatory performance compared with WC.

Factors influencing participation rate in a baseline survey of a genetic cohort in Japan

BACKGROUND

Although many studies have examined factors that influence the response to postal questionnaires, few have addressed baseline recruitment for cohort studies involving genetic analyses. The aim of this study was to describe the method used for a baseline survey, the Japan Multi-institutional Collaborative Cohort Study (J-MICC Study), in Saga Prefecture, and to examine the factors that might influence the recruitment of participants in such studies.

METHODS

The Saga J-MICC Study is an ongoing population-based prospective cohort study of the genetic and environmental interactions associated with lifestyle-related disease. From 2005 through 2007, a total of 61 447 residents between the ages of 40 and 69 were invited by mail to participate in this study. The survey date and time were arranged by telephone.

RESULTS

Among that population, 31 002 (50.5%) responded and 12 078 (19.7%) agreed to participate. A completed questionnaire and blood pressure and anthropometric data were collected from all participants; blood, DNA specimens, and accelerometer measures were obtained from the great majority of them. Female sex and older age were associated with a higher participation rate. In addition, the convenience of the survey location and the sending of a reminder significantly improved the participation rate (odds ratio, 1.3).

CONCLUSIONS

Our findings suggest that making the survey location as convenient as possible and sending a reminder can both substantially improve participation rate in population-based studies.

Interaction between cytochrome P450 1A2 genetic polymorphism and cigarette smoking on the risk of hepatocellular carcinoma in a Japanese population

Limited epidemiological evidence suggests that genetic polymorphisms of drug-metabolizing enzymes such as cytochrome P450 (CYP), glutathione S-transferase (GST) and N-acetyltransferase (NAT) may be involved in tobacco-related hepatocarcinogenesis. We conducted a case-control study, including 209 incident cases with hepatocellular carcinoma (HCC) and two different control groups [275 hospital controls and 381 patients with chronic liver disease (CLD) without HCC], to investigate whether CYP1A1, CYP1A2, CYP2A6, CYP2E1, GSTM1 and NAT2 polymorphisms are related to the risk of HCC with any interaction with cigarette smoking. Overall, no significant associations with HCC were observed for any genotypes against either control group. However, we found a significant interaction (P = 0.0045) between CYP1A2 -3860G>A polymorphism and current smoking on HCC risk when we compared HCC cases with CLD patients; adjusted odds ratios [ORs; and 95% confidence intervals (CIs)] for G/A and A/A genotypes relative to G/G genotype were 0.28 (0.12-0.66) and 0.18 (0.04-0.94), respectively, among current smokers (P trend = 0.002), as compared with 1.28 (0.80-2.06) and 0.76 (0.34-1.71), respectively, among never/former smokers (P trend = 0.96). Similarly, in CYP1A2 G/G genotype, significant risk increase was observed for current smoking (OR = 4.08, 95% CI = 2.02-8.25) or more recent cigarette use (e.g. pack-years during last 5 years, P trend = 0.0003) but not in G/A and A/A genotypes combined (OR for current smoking = 1.39, 95% CI = 0.63-3.03; P trend for pack-years during last 5 years = 0.40). These results suggest that the CYP1A2 -3860G>A polymorphism modifies the smoking-related HCC risk among CLD patients.

Interaction between interleukin-1beta -31T/C gene polymorphism and drinking and smoking habits on the risk of hepatocellular carcinoma among Japanese

The risk of hepatocellular carcinoma (HCC) increases with the severity of hepatic inflammation. Interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha are proinflammatory cytokines with multiple biological effects and may play essential roles in inflammation-linked tumor development. We conducted a case-control study including 209 incident HCC cases and two control groups (275 hospital controls and 381 patients with chronic liver disease [CLD] without HCC) to investigate whether IL-1B and TNF-A gene polymorphisms influence HCC susceptibility with any interaction with alcohol and tobacco. By comparing HCC cases with CLD patients, we found that IL-1B -31T/C polymorphism was associated with HCC risk among never drinkers and current smokers; adjusted odds ratios (and 95% confidence intervals) for C/T and T/T genotypes compared with C/C genotype were 1.70 (0.76-3.77) and 2.46 (1.05-5.76) (P trend=0.03), respectively, among never drinkers, and 1.53 (0.60-3.99) and 2.54 (0.81-7.95) (P trend=0.11), respectively, among current smokers. Similarly, HCC risk associated with heavy alcohol intake and current smoking differed by this polymorphism among CLD patients. IL-1B -31T/C polymorphism may modify HCC risk in relation to alcohol intake or smoking.

Single-dose ethanol administration downregulates expression of cytochrome p450 2E1 mRNA in aldehyde dehydrogenase 2 knockout mice

The polymorphism of aldehyde dehydrogenase 2 (ALDH2), denoted ALDH2*2, is very common in East Asian origin. Acetaldehyde, an intermediate metabolite of ethanol, is metabolized very slowly in people with ALDH2*2 because the mutant ALDH2 protein lacks the activity of acetaldehyde metabolism. On the other hand, it is well established that one of the cytochrome P450 enzymes, CYP2E1, is an activator of carcinogens (e.g., nitorosamines) and a generator of oxidative stress, and it is shown that CYP2E1 was induced by ethanol via gene transcriptional regulation. In the present study, to examine the consequences of ALDH2 polymorphism on transcriptional regulation of CYP2E1 in liver tissue, Aldh2+/+ and Aldh2-/- mice were orally administered 5 g/kg body weight of ethanol and the levels of CYP2E1 mRNA in liver tissue then analyzed. The level of CYP2E1 mRNA 12h after the ethanol administration tended to be higher than the 0-h group in Aldh2+/+ mice, however, it was significantly lower than the 0-h group in Aldh2-/- mice. These findings suggest that single-dose ethanol administration downregulates the expression of cytochrome p450 2E1 mRNA in the presence of inactive ALDH2.

Analysis of Urinary Metabolites of Polycyclic Aromatic Hydrocarbons in Incineration Workers

Incineration workers are exposed to various pyrolysis products of organic materials, heavy metals and polycyclic aromatic hydrocarbons (PAHs). In this study, the exposure of incineration workers to PAHs was evaluated by measuring urinary metabolites of pyrene and naphthalene. The concentrations of urinary 1-hydroxypyrene (1OHP), a metabolite of pyrene, and 2-naphthol (2NP), a metabolite of naphthalene, were measured among 100 workers in 4 different types of incinerators, both before and after their work shifts. These incinerators were two old types, one modern type and one outdoors. The medians of urinary 1OHP of before and after the work shifts obtained from all workers were 0.067 and 0.044 mug/gCr, respectively; and the medians of urinary 2NP were 7.5 and 10.0 mug/gCr, respectively. A significant increase of 2NP after the work shift was found at one old incinerator. A significant decrease of metabolites was found at the other old incinerator. Significant correlations were found between urinary metabolites and cigarettes smoked per day. The effect of smoking on urinary metabolite levels was also important. Significant correlations were found between urinary 1OHP and 2NP levels in all workers. In multiple regression analysis smoking habit and incinerator type were found as significant factors. The improvement of the work environment, through decreasing exposure to both tobacco smoke and hazardous work shift-related substances, should be an occupational health aim.

Lack of aldehyde dehydrogenase ameliorates oxidative stress induced by single-dose ethanol administration in mouse liver

Polymorphism of aldehyde dehydrogenase 2 (ALDH2), denoted ALDH2*2, is far more common in East Asian countries. Acetaldehyde, an intermediate metabolite of ethanol, is metabolized very slowly in people who have ALDH2*2, as the mutated ALDH2 lacks acetaldehyde metabolizing activity. On the other hand, it is well established that metabolism of ethanol causes oxidative stress in liver tissue. To examine the consequences of this polymorphism on ethanol-induced oxidative stress in liver tissue, we conducted a study using Aldh2 knockout mice. Aldh2+/+ and Aldh2-/- mice were orally administered ethanol at a dose of 5g/kg body weight. Levels of malondialdehyde, an indicator of oxidative stress, and glutathione, a key antioxidant, in liver tissue were analyzed 0-24h after administration. Levels of malondialdehyde were significantly lower in Aldh2-/- mice than in Aldh2+/+ mice at 12h after injection, while levels of glutathione were higher in Aldh2-/- mice than in Aldh2+/+ mice at 6 and 12h after injection. Our results suggest that a lack of ALDH ameliorates ethanol-induced oxidative stress in liver tissue.

hOGG1 Ser326Cys polymorphism and risk of hepatocellular carcinoma among Japanese

BACKGROUND

The Ser326Cys polymorphism in human oxoguanine glycosylase 1 (hOGG1), which is involved in the repair of 8-hydroxy-2-deoxyguanine in oxidatively damaged DNA, has been associated with susceptibility to certain cancers, but has not been examined in causation of hepatocellular carcinoma (HCC).

METHODS

We conducted a case-control study to investigate whether this polymorphism was related to HCC risk with any interaction with alcohol consumption and cigarette smoking. Genotyping was performed by a polymerase chain reaction with confronting two-pair primers among 209 newly diagnosed HCC cases, 275 hospital controls, and 381 patients with chronic liver disease (CLD) without HCC.

RESULTS

Overall, the hOGG1 genotype was not significantly associated with HCC; adjusted odds ratios (and 95% confidence intervals) for the Ser/Cys and Cys/Cys genotypes compared with the Ser/Ser genotype were 0.79 (0.35-1.79) and 0.48 (0.18-1.27) against hospital controls, and 1.51 (0.96-3.37) and 0.86 (0.50-1.47) against CLD patients. We could not detect any significant gene-alcohol interaction (p = 0.95 or 0.16) or gene-smoking interaction (p = 0.70 or 0.69).

CONCLUTIONS

These results suggest that the hOGG1 Ser326Cys polymorphism may not play a major role as an independent factor in hepatocarcinogenesis.

Decreasing urinary PAH metabolites and 7-methylguanine after smoking cessation

OBJECTIVE

Humans are exposed to various carcinogens by smoking. Urinary metabolites of polycyclic aromatic hydrocarbons (PAH), one of the major carcinogens in cigarette smoke, were measured as the environmental carcinogen exposure marker for humans. We evaluated urinary exposure markers for smoking cessation.

METHOD

In this study, we measured cigarette smoke exposure markers, such as urinary cotinine, PAH exposure markers, such as urinary 1-hydroxypyrene (1-OHP), 2-naphthol (2-NP) and 1-naphthol (1-NP), as well as a methylating chemical exposure marker, 7-methylguanine (7-MeG). The before smoking cessation levels of these markers, and the after smoking cessation levels were then compared. Eighteen subjects participated in this smoking cessation program.

RESULTS

Levels of all of four markers were found to have decreased by 19-54% after smoking cessation. Urinary cotinine, 1-OHP, 2-NP and 7-MeG levels were found to have significantly decreased after smoking cessation. There were positive correlations between cotinine and three urinary PAH markers and between 1-OHP, 2-NP and 7-MeG.

CONCLUSION

PAH metabolites were better biomarkers of smoking cessation than 7-MeG. Analyzing urinary metabolites or urinary DNA adducts is suitable for epidemiological studies.

Influence of alcohol consumption and gene polymorphisms ofADH2andALDH2on hepatocellular carcinoma in a Japanese population

Although alcohol intake as well as hepatitis viruses has been associated with hepatocellular carcinoma (HCC), gene-alcohol interactions on HCC risk remain to be elucidated. We conducted a case-control study to examine whether polymorphisms of alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2) modified the HCC risk depending on the amount of alcohol intake. ADH2 and ALDH2 genotyping was performed by a duplex polymerase chain reaction with confronting two-pair primers in 209 newly diagnosed HCC cases and 2 different controls [275 hospital controls and 381 patients with chronic liver disease (CLD)]. Multiple logistic regression analyses revealed that heavy drinkers consuming >or=3 "go"s/day of sake (69 g of ethanol/day) showed an increased risk of HCC based on comparison of HCC cases with hospital controls [adjusted odds ratio (OR) = 13.5; 95% confidence interval (CI) 3.3-54.3] or CLD patients (adjusted OR = 7.0; 95% CI 2.5-19.2), whereas the overall risk was not elevated among light to moderate drinkers consuming <3 "go"s/day. Interestingly, light to moderate drinking was associated with an increased risk among those with ALDH2*1/*2 (adjusted OR = 4.5 or 2.0), but not among those with ALDH2*1/*1 (adjusted OR = 0.8 or 1.0; p interaction = 0.03 or 0.13). However, this gene-alcohol interaction was not observed for heavy drinking. Among light to moderate drinkers, people with the combination of ALDH2*1/*2 and ADH2*2/*2 revealed the highest risk of HCC. These findings indicate that the ALDH2 polymorphism may modify HCC risk among light to moderate drinkers.

Sleep and daytime sleepiness in upper airway resistance syndrome compared to obstructive sleep apnoea syndrome

This study has investigated differences in the nocturnal sleep and daytime sleepiness among patients with obstructive sleep apnoea syndrome (OSAS), upper airway resistance (UARS), sleep hypopnoea syndrome, and normal control subjects, using sleep scoring and spectral activity analysis of the electroencephalogram (EEG). Twelve nonobese males with UARS aged 30-60 yrs were recruited. These subjects were strictly matched for age and body mass index with twelve OSAS patients, 12 sleep hypopnoea syndrome patients, and 12 normal controls, all male. Daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS) and the Multiple Sleep Latency Test (MSLT). The macrostructure of sleep was determined using international criteria and spectral analysis of the sleep EEG was obtained from a central lead. The sleep macrostructure of OSAS and UARS patients was significantly different from that of controls. These patients were also sleepier during the daytime than controls. Complaints of tiredness and daytime sleepiness, ESS and MSLT scores were similar in the different patient groups. Mild dysmorphia was present in all three patient groups. However, nocturnal sleep was significantly different among the different groups. OSAS patients had significantly more awake time during sleep than the UARS patients. The spectral activity of the total sleep time of the patient groups also differed significantly from that of controls. When the sleep spectral activity of UARS and OSAS patients were compared, OSAS patients had less slow wave sleep activity than UARS patients. UARS patients had a significantly higher absolute power in the 7-9 Hz bandwidth than OSAS patients. The absolute delta power over the different sleep cycles was also different between controls and patients, and between UARS and OSAS patients. There are clear differences in the macrostructure and spectral activity of sleep between upper airway resistance and obstructive sleep apnoea syndrome patients, demonstrated by differences in the cortical activity recorded in the central lead during sleep. Despite these nocturnal sleep differences, the tests of subjective daytime sleepiness are not significantly different.

Genetic Diversity of Japanese Strains of Ralstonia solanacearum

ABSTRACT The genetic diversity of 74 Japanese strains of Ralstonia solanacearum was assessed by pathogenicity tests and the repetitive sequencebased polymerase chain reaction (rep-PCR) fingerprint method. Based on their genomic fingerprints, biovar N2 strains were divided into two distinct groups, one consisting of potato isolates belonging to race 3, and the other consisting of tomato, eggplant, pepper, and tobacco isolates belonging to race 1. Biovar 3 strains had low average similarity and were divided into five groups that differed in original host or pathogenicity. Biovar 4 strains consisted of only one group at the 80% similarity level. Comparative analysis of the rep-PCR fingerprints of 78 strains, including six biovars from Japan and various countries, revealed two main clusters. Cluster 1 comprised all biovar 3, 4, and 5 strains, biovar 1 strains from Reunion, and some biovar N2 strains from Japan. Cluster 2 included most of the biovar 1, 2, and N2 strains. The fingerprints showed low average similarity with biovar N2 strains from Japan and Brazil.

The potent role of increased sympathetic tone in pathogenesis of essential hypertension with neurovascular compression

OBJECTIVE

To study the role of increased sympathetic tone in pathogenesis of hypertension in patients with essential hypertension with neurovascular compression.

METHODS

Twenty-three patients with essential hypertension, 13 patients with secondary hypertension, and 46 normotensive subjects were investigated. Neurovascular compression was evaluated by MRT. The power spectral components of heart rate variability as indices of autonomic nerve tone were determined to investigate the possibility that sympathetic tone mediates the neurovascular compression-induced increase in blood pressure.

RESULTS

Neurovascular compression of the rostral ventrolateral medulla (RVLM) was observed in 70% of essential hypertension group, none of secondary hyperension group and 16% of normotensive group (P < 0.001). The age-adjusted low-frequency power spectral density (A-PSD) (0.04 to 0.15 Hz), which is an index of sympathetic tone, was significantly higher in patients with essential hypertension (139.5 +/- 6.7%) with neurovascular compression than in essential hypertension patients without neurovascular compression (92.2 +/- 6.8%), normotensive subjects with (102.8 +/- 13.0%) and without neurovascular compression (100.1 +/- 4.1%), and patients with secondary hypertension (95.7 +/- 10.2%) (P < 0.001). There was no significant difference in the high-frequency A-PSD (0.15 to 0.40 Hz), which is an index of vagal tone, among groups.

CONCLUSIONS

Neurovascular compression was not always associated with an increase in sympathetic nerve tone. Hypertension was present in subjects with neurovascular compression, who had increased sympathetic tone but not in those with normal sympathetic tone. An increase in sympathetic tone may mediate the neurovascular compression-induced increase in blood pressure. Journal of Human Hypertension (2000) 14, 807-811

Noninvasive, continuous evaluation of peripheral vascular resistance in humans

We sought a noninvasive alternative method of monitoring peripheral vascular resistance continuously in humans, based on the analysis of arterial pressure waveforms. Radial arterial pressure waveforms were recorded noninvasively with a tonometer and analysed using a neural network method. To test the accuracy of this method, the peripheral vascular resistance was also determined by an invasive thermodilution method using a Swan-Ganz catheter in 20 subjects. To test the method in a clinical application, peripheral vascular resistance was determined by the noninvasive method before and after administration of nifedipine in 6 patients with essential hypertension. Neural network analysis of waveforms reliably yielded values between 0.00 and 1.00. Peripheral vascular resistance determined by neural network analysis and according to the invasive method showed a significant (p< 0.005) positive linear correlation. The peripheral vascular resistance measured by neural network analysis showed a significant (p< 0.05) decrease 30 min after administration of nifedipine, paralleling a decrease in blood pressure. Neural network analysis of tonometric radial artery waveforms provides an accurate, noninvasive, and continuous index of peripheral vascular resistance in human subjects. This simple method should permit more extensive homodynamic studies and larger epidemiological surveys in contrast to those undertaken using invasive techniques.