PubMed Health⌕ Search

Biomedical subjects

Akira Okayama

Publications and source records attributed to Akira Okayama.

At least 19 recordsLinked to original sources
PubMed2007

Medical costs of obese Japanese: a 10-year follow-up study of National Health Insurance in Shiga, Japan.

BACKGROUND: For the Japanese population, a body mass index (BMI) of 25.0-29.9 is classified as obesity and is a risk factor for cardiovascular disorders such as hypertension. METHODS: A cohort study to clarify obesity costs for a Japanese population was conducted utilizing baseline BMI and medical costs over a 10-year follow-up period. The participants were 4502 community dwelling Japanese National Health Insurance (NHI) beneficiaries aged 40-69 years. According to their baseline BMI values (kg/m(2)), participants were classified into the following three categories: BMI < 18.5, 18.5 < or = BMI < 25.0 and 25.0 < or = BMI. Medical costs per person per month were compared among the three categories. Excess medical costs attributable to the 25.0 < or = BMI category compared to the 18.5 < or = BMI < 25.0 category were estimated. RESULTS: Approximately 20% of the Japanese population studied had a BMI of 25.0 or over. A J-shaped relationship between BMI and personal total medical costs was observed. Personal total medical costs per month determined from the 10-year follow-up in each category were 189 Euros (BMI < 18.5), 134 Euros (18.5 < or = BMI < 25.0) and 155 Euros (25.0 < or = BMI). A J-shaped pattern was observed after adjusting for age, sex, smoking and drinking habits, and excluding early deceased participants. Furthermore, smoking habit did not modify the J-shaped pattern of total medical costs. The estimated excess medical costs for the 25.0 < or = BMI category represented 3.1% of the total medical costs for the entire study population (634 105 Euros). CONCLUSION: The Japanese NHI beneficiaries with a BMI of 25.0 or over showed increased medical costs compared to those with a BMI of 18.5-24.9.

Adult↗
PubMed2006

Relation of adult height with stroke mortality in Japan: NIPPON DATA80.

BACKGROUND AND PURPOSE: The age-adjusted stroke mortality rate in Japan was the highest in the world from 1950 to the 1970s, but it started to dramatically decrease after 1965. In addition to improved management of high blood pressure, the increase in average height might also contribute to this reduction. The present study investigates whether height is an independent risk for stroke mortality in Japan. METHODS: Among participants of the National Survey on Cardiovascular Diseases in 1980 who were randomly selected from the Japanese population, we followed up 3969 and 4955 Japanese men and women without prior cardiovascular disease for a maximum of 19 years and observed 158 and 132 stroke deaths. RESULTS: Height was inversely correlated with age and with crude stroke mortality. The relationship was attenuated in men when we adjusted for age or other possible confounders (multivariate adjusted relative hazards of a 5-cm increase of height for stroke mortality: 0.92, 95% CI: 0.79 to 1.08). For women, the inverse relationship (relative hazard: 0.77: 95% CI: 0.64 to 0.91) remained after multivariate adjustment. These relationships persisted when we stratified participants by age. CONCLUSIONS: Height is inversely related to stroke mortality and the relationship is statistically significant among Japanese women.

Adult↗
PubMed2006

Genotypes of vitamin K epoxide reductase, gamma-glutamyl carboxylase, and cytochrome P450 2C9 as determinants of daily warfarin dose in Japanese patients.

The dose required for the anticoagulant effect of warfarin exhibits large inter-individual variations. This study sought to determine the contribution of four genes, vitamin K epoxide reductase (VKORC1), gamma-glutamyl carboxylase (GGCX), calumenin (CALU), and cytochrome P450 2C9 (CYP2C9) to the warfarin maintenance dose required in Japanese patients following ischemic stroke. We recruited 93 patients on stable anticoagulation with a target International Normalized Ratio (INR) of 1.6-2.6. We genotyped eleven representative single nucleotide polymorphisms (SNPs) in the three genes involved in vitamin K cycle and the 42613A>C SNP in CYP2C9, known as CYP2C93, and then examined an association of these genotypes with warfarin maintenance doses (mean+/-SD=2.96+/-1.06 mg/day). We found an association of effective warfarin dose with the -1639G>A (p=0.004) and 3730G>A genotypes (p=0.006) in VKORC1, the 8016G>A genotype in GGCX (p=0.022), and the 42613A>C genotype in CYP2C9 (p=0.015). The model using the multiple regression analysis including age, sex, weight, and three genetic polymorphisms accounted for 33.3% of total variations in warfarin dose. The contribution to inter-individual variation in warfarin dose was 5.9% for VKORC1 -1639G>A, 5.2% for CYP2C9 42613A>C, and 4.6% for GGCX 8016G>A. In addition to polymorphisms in VKORC1 and CYP2C9, we identified GGCX 8016G>A, resulting in the missense mutation R325Q, as a genetic determinant of warfarin maintenance dose in Japanese patients.

Aged↗
PubMed2006

gamma-Glutamyltransferase predicts cardiovascular death among Japanese women.

The clinical importance of gamma-glutamyltransferase (GGT) has recently been debated. Although some studies have suggested that the relationship between GGT and cardiovascular disease (CVD) mortality is independent of alcohol consumption, to our knowledge no studies have reported the relationship between GGT and CVD mortality in never-drinker subgroups. Since Japanese women are known to have a lower prevalence of alcohol consumption, we examined whether GGT predicts CVD mortality in never-drinkers. We followed 2724 Japanese men and 4122 Japanese women without prior CVD or liver dysfunction for 9.6 years and observed 83 and 82 CVD deaths, respectively. Current alcohol drinkers comprised 59% of men and 7% of women. Among women, the multiple adjusted hazard ratio (HR) for CVD mortality compared with the reference group (GGT: 1-12 U/L) was 2.88 (95% confidence interval (CI), 1.14-7.28) for the elevated group (GGT>or=50 U/L). This positive relationship was unchanged in the never-drinkers subgroup (HR for log-transformed continuous GGT, 1.62 (95% CI, 1.11-2.37)). No significant relationships were observed in men. GGT displays a strong positive association with CVD mortality among Japanese women, for whom the prevalence of ever-drinkers is very low. Exploring the significance and biological mechanisms of GGT might provide useful insights into CVD prevention.

Biomarkers↗
PubMed2006

EEG findings in early-stage corticobasal degeneration and progressive supranuclear palsy: a retrospective study and literature review.

OBJECTIVE: Although neuroimaging and electrophysiological tests are potentially useful to distinguish corticobasal degeneration (CBD) from progressive supranuclear palsy (PSP), little is known about the diagnostic value of electroencephalography (EEG) for their distinction. We assessed the value of EEG for differentiating CBD from PSP. METHODS: We reviewed conventional EEGs recorded at an early stage of disease in 10 CBD patients and 14 PSP patients. We focused on slowing of background activity (SBA), frontal intermittent rhythmic delta activity (FIRDA) and focal slow waves (FSWs). Statistical analysis was performed by Fisher's exact test. RESULTS: SBA was observed in 1 CBD patient and 2 PSP patients. FSWs were found in 8 CBD patients (80.0%), but only 2 PSP patients (14.3%) (p=0.002); they appeared contralateral to the dominantly-affected side in 6 of 8 CBD patients, and ipsilateral to the side with most atrophy on MRI in 7 of 8 CBD patients. FIRDA was observed in 2 CBD patients (20.0%) and 5 PSP patients (35.7%) (p=0.357). CONCLUSIONS: FSWs are characteristic of CBD, but FIRDA was not disease-specific. SIGNIFICANCE: FSWs on EEG, in addition to clinical criteria, yield useful supplementary information to distinguish between these diseases at early stages.

Adult↗
PubMed2006

Body mass index and risk of stroke mortality among a random sample of Japanese adults: 19-year follow-up of NIPPON DATA80.

BACKGROUND: The relationship between body mass index (BMI) and stroke mortality remains unclear. The aim of the present study was to elucidate the relationship between BMI and stroke death in a representative cohort of Japanese men and women. METHODS: We analyzed a database of 9,526 men and women aged 30 years and older who were randomly selected throughout Japan in 1980. These individuals had no history of stroke and were followed for 19 years. Hazard ratios (HR) and their 95% confidence intervals (CI) of deaths due to total stroke, cerebral infarction, and intracerebral hemorrhage were examined using Cox's proportional hazards regression models of BMI levels. RESULTS: A U-shaped association between BMI and cerebral infarction mortality was observed. Participants with the highest BMI category (BMI > or = 30.0) showed a significantly highest HR for cerebral infarction (HR 2.46, 95% CI 1.01-5.99). The excess risk at the lower extreme of the BMI was confined to men. These associations did not change after excluding deaths occurring in the first 2 years of follow-up. CONCLUSIONS: In the Japanese general population, a U-shaped association between BMI and cerebral infarction mortality was found and the excess risk at the lower extreme of the BMI was confined to men.

Adult↗
PubMed2006

Dietary factors related to higher plasma fibrinogen levels of Japanese-americans in hawaii compared with Japanese in Japan.

OBJECTIVE: We investigated whether dietary factors explain higher plasma fibrinogen levels in Japanese emigrants living a Western lifestyle in Hawaii compared with Japanese in Japan. METHODS AND RESULTS: Plasma fibrinogen and nutrient intakes were examined by standardized methods in men and women 40 to 59 years of age from a Japanese-American sample in Hawaii (100 men and 106 women) and 4 population samples in Japan (569 men and 567 women). Multiple linear regression models were used to examine the relationship between dietary factors and the plasma fibrinogen difference between Hawaii and Japan. Average plasma fibrinogen was significantly higher in Hawaii compared with Japan (P<0.001 in both genders). In multiple linear regression analyses with each dietary variable considered separately, body mass index reduced the plasma fibrinogen difference between Hawaii and Japan by 20.4%; iron intake (mg/1000 kcal) and estimated total sugar intake (%kcal) reduced this difference by 30.0% and 14.4%, respectively. In a model that included body mass index, iron, estimated total sugars, and caffeine (also age and gender), this difference was reduced by 61.3% (from 42.2 to 16.3 mg/dL). CONCLUSIONS: Higher intake of iron, sugar, and caffeine, in addition to obesity, account largely for higher fibrinogen levels with Westernized lifestyle.

Adult↗
PubMed2006

The relationship between serum total cholesterol and all-cause or cause-specific mortality in a 17.3-year study of a Japanese cohort.

No study has shown a positive relationship between hypercholesterolemia and all-cause mortality in the Japanese population. Therefore, a cohort study of 17.3 years' duration was conducted on 9216 participants aged 30 years or older, selected randomly from throughout Japan. In both the lowest (<4.14mmol/L, 160mg/dl) and highest (>or=6.71mmol/L, 260mg/dl) total cholesterol (TC) groups, there was a positive association between TC and risk of all-cause mortality (hazard ratio (HR) 1.19; 95% confidence interval (CI), 1.03-1.37 and 1.36 (95% CI, 1.05-1.77), respectively). The lowest TC group had an increased risk of liver disease (HR 3.03; 95% CI, 1.70-5.43), whereas the highest TC group had an increased risk of coronary heart disease (HR 3.81; 95% CI, 1.70-5.43). After exclusion of deaths due to liver disease during the entire follow-up period and all-cause deaths within the first 5 years of follow-up, the increased HR in the lowest TC group disappeared (HR 1.05; 95% CI, 0.89-1.24). Although the cut-off point seemed to be higher than that for Western populations, hypercholesterolemia was shown to be positively associated with all-cause mortality in Japan.

Adult↗
PubMed2006

Haplotype of thrombomodulin gene associated with plasma thrombomodulin level and deep vein thrombosis in the Japanese population.

INTRODUCTION: Thrombomodulin (TM) is an essential cofactor in protein C activation by thrombin. Here, we evaluated the contribution of genetic variations in the TM gene to soluble TM (sTM) level and deep vein thrombosis (DVT) in Japanese. PATIENTS AND METHODS: We sequenced the TM putative promoter, exon, and 3'-untranslated region in DVT patients (n=118). Among 17 genetic variations we identified, two missense mutations (R385K, D468Y) and three common single nucleotide polymorphisms (-202G>A, 2487A>T, 2729A>C) were genotyped in a general population of 2247 subjects (1032 men and 1215 women) whose sTM levels were measured. We then compared the frequency of these mutations in DVT patients with that in the age, body mass index-adjusted population-based controls. RESULTS: We identified one neutral mutation (H381) and three missense mutations (R385K; n=2, A455V; n=53 heterozygous, n=14 homozygous, D468Y; n=2) of TM in the DVT patients. Age-adjusted mean values of sTM were lower in C-allele carriers of 2729A>C than in noncarriers in the Japanese general population (women: 16.7+/-0.3 U/ml vs. 17.9+/-0.2 U/ml, p<0.01, men: 19.4+/-0.3 U/ml vs. 20.4+/-0.3 U/ml, p=0.03). Additionally, the CC genotype of this mutation was more common in the male DVT patients than in the male individuals of the general population (odds ratio=2.76, 95% confidence interval=1.14-6.67; p=0.02). This mutation was in linkage disequilibrium (r-square>0.9) with A455V mutation. CONCLUSIONS: TM mutations, especially those with a haplotype consisting of 2729A>C and A455V missense mutation, affect sTM levels, and may be associated with DVT in Japanese.

3' Untranslated Regions↗
PubMed2006

Functional network of the basal ganglia and cerebellar motor loops in vivo: different activation patterns between self-initiated and externally triggered movements.

The basal ganglia and cerebellar loops are known to participate differently in self-initiated (SI) and externally triggered (ET) movements. However, no previous neuroimaging studies have illustrated functional organization of these loops in vivo. Here, we aimed to functionally visualize these loops during motor execution using functional magnetic resonance imaging (fMRI) with structural equation modeling (SEM). Twelve normal subjects (24-29 years old) were scanned while performing five different frequencies of sequential left finger movements using either SI or ET movements. Random effect analysis combined with a parametric approach revealed a significant positive linear dependence of cerebral activation upon movement rate in the right Put, GPi, VL, SMC and SMA during SI tasks. During ET tasks, significant positive linear relationships were found in the right SMC, VPL, left CB and DN, whereas tendency for linear relationships was seen in the right PMv. SEM further showed significant interactions within the right basal ganglia-thalamo-motor loop during SI tasks. In contrast, there were significant interactions within the entire right cerebral hemisphere-left cerebellar loop involving CB, DN, VPL, PMv and SMC during ET tasks. Therefore, our modeling approach enabled identification of different contributions of the motor loops of basal ganglia and cerebellum to SI and ET tasks during motor execution.

Adult↗
PubMed2006

Association between protein intake and blood pressure: the INTERMAP Study.

BACKGROUND: Findings from epidemiological studies suggest an inverse relationship between individuals' protein intake and their blood pressure. METHODS: Cross-sectional epidemiological study of 4680 persons, aged 40 to 59 years, from 4 countries. Systolic and diastolic blood pressure was measured 8 times at 4 visits. Dietary intake based on 24-hour dietary recalls was recorded 4 times. Information on dietary supplements was noted. Two 24-hour urine samples were obtained per person. RESULTS: There was a significant inverse relationship between vegetable protein intake and blood pressure. After adjusting for confounders, blood pressure differences associated with higher vegetable protein intake of 2.8% kilocalories were -2.14 mm Hg systolic and -1.35 mm Hg diastolic (P<.001 for both); after further adjustment for height and weight, these differences were -1.11 mm Hg systolic (P<.01) and -0.71 mm Hg diastolic (P<.05). For animal protein intake, significant positive blood pressure differences did not persist after adjusting for height and weight. For total protein intake (which had a significant interaction with sex), there was no significant association with blood pressure in women, nor in men after adjusting for dietary confounders. There were significant differences in the amino acid content of the diets of persons with high vegetable and low animal protein intake vs the diets of persons with low vegetable and high animal protein intake. CONCLUSIONS: Vegetable protein intake was inversely related to blood pressure. This finding is consistent with recommendations that a diet high in vegetable products be part of healthy lifestyle for prevention of high blood pressure and related diseases.

Adult↗
PubMed2006

The inverse relationship between serum high-density lipoprotein cholesterol level and all-cause mortality in a 9.6-year follow-up study in the Japanese general population.

In populations with higher high-density lipoprotein cholesterol (HDL-C) levels and lower coronary mortality than Western populations, such as in Japan, the beneficial effect of HDL-C on all-cause mortality may be different. Furthermore, prior studies have not focused on very high level of HDL-C. A total of 7175 community Japanese residents without a past history of cardiovascular disease in 300 randomly selected districts were followed for 9.6 years. During follow-up, there were 636 deaths. The multivariate adjusted hazard ratio (HR) of HDL-C for all-cause or cause-specific mortality was calculated using a Cox proportional hazard model adjusted for other cardiovascular risk factors. The all-cause mortality suggested an inverse, graded relation with HDL-C categories; HR for the very high HDL-C category (> or = 1.82 mmol/L), compared with the reference group (1.04-1.55 mmol/L), was 0.73 (95% confidence interval, C.I., 0.50-1.06) for men, 0.63 (95% C.I., 0.41-0.94) for women and 0.70 (95% C.I., 0.53-0.93) when men and women were combined. Serum HDL-C as a continuous variable showed a significant inverse association with all-cause mortality. The cardiovascular mortality indicated a non-significant but inverse graded relation with HDL-C categories. As in the many Western populations, serum HDL-C levels were inversely associated with all-cause mortality in the Japanese general population.

Biomarkers↗
PubMed2006

Age-specific effects of systolic and diastolic blood pressures on mortality due to cardiovascular diseases among Japanese men (NIPPON DATA80).

OBJECTIVE: To clarify the relationship between mortality due to cardiovascular diseases (CVD) and systolic blood pressure (SBP) and diastolic blood pressure (DBP) in young and elderly Japanese men in the absence of antihypertensive treatments. DESIGN: A 19-year cohort study using the 1980 National Survey of Cardiovascular Diseases and the identification of the underlying causes of death using national vital statistics data. METHODS: In 1999, a 19-year follow-up study was conducted among participants randomly selected from the Japanese population for the 1980 National Survey of Cardiovascular Diseases. Among the male participants that were not receiving antihypertensive treatment, information was obtained for about 91.3% of the subjects (n = 3779). Age-adjusted mortality rates using the person-year method were calculated to compare the relationships of SBP and DBP levels with CVD mortality for different age groups (aged 30-64, 65-74, and 75 years or more). RESULTS: The total number of observed person-years was 64 598 and the number of CVD-related deaths after 19 years was 253. Both SBP and DBP levels were significantly and linearly related to CVD mortality in the age groups 30-64 years (P < 0.001 and P = 0.01, respectively) and 65-74 years (P < 0.001 and P = 0.03, respectively). In the group of participants that were at least 75 years old, however, no significant increase in the relative risk of CVD was observed with increasing DBP levels (P = 0.156), whereas the relative risk of CVD increased significantly with increasing SBP levels (P = 0.038). Multivariate analysis adjusting for major risk factors confirmed these relationships. Standardized hazard ratios (95% confidence intervals) of SBP were 1.53 (1.19-1.96) for 30-64 year olds, 1.70 (1.31-2.20) for 64-74 year olds, and 1.23 (1.03-1.47) for participants 75 years old or more, whereas those of DBP were 1.52 (1.12-2.06), 1.60 (1.21-2.10), and 1.10 (0.94-1.28), respectively. CONCLUSIONS: These data show that elevated SBP is an independent risk factor for CVD mortality for Japanese men of all ages, whereas elevated DBP is not an independent risk factor for CVD mortality for elderly men.

Adult↗
PubMed2006

Medical costs of patients with hypertension and/or diabetes: A 10-year follow-up study of National Health Insurance in Shiga, Japan.

BACKGROUND AND METHODS: A cohort study investigating medical costs associated with the combination of hypertension and diabetes was conducted. The participants included 4535 community-dwelling Japanese individuals, aged 40-69 years, who were classified into the following four categories: 'Neither hypertension nor diabetes', 'Hypertension alone', 'Diabetes alone' or 'Both hypertension and diabetes'. Medical costs per person per month were compared among the four categories. RESULTS AND CONCLUSION: Of the study population, 1.3% had both hypertension and diabetes. During the 10-year follow-up period, participants with both hypertension and diabetes incurred higher medical costs, as compared with those without hypertension, diabetes or their combination, even after adjustment for other confounding factors.

Adult↗
PubMed2006

Effect of conventional risk factors for excess cardiovascular death in men: NIPPON DATA80.

BACKGROUND: The present study examined how sex differences in conventional risk factors for cardiovascular disease (CVD), especially smoking, account for excess male mortality from CVD in Japan. METHODS AND RESULTS: In a 14-year follow-up study, causes of death were ascertained among 10,546 Japanese aged 30 years or older at the baseline. The proportion of the excess male risk of CVD explained by the differences in risk factors was estimated as (HR0-HR1)/(HR0-1), where HR0 is the age-adjusted hazard ratio (men vs women) and HR1 is the age and risk factor-adjusted hazard ratio. The age-adjusted male:female ratios were 1.60 (95% confidence interval (CI), 1.32-1.94) for CVD, 1.75 (95% CI, 1.33-2.30) for stroke, and 1.55 (95% CI, 0.97-2.49) for coronary heart disease. The proportion of excess male risk of CVD explained by smoking was 46% and excess risk explained by all risk factors including smoking was 36%. In men, drinking habits decreased the excess risk of CVD. Except for the association between drinking habits and CVD, the impact of the hazard ratios of conventional risk factors had no sex difference. CONCLUSIONS: Smoking contributes substantially to excess male mortality from CVD when the smoking rates vary substantially by sex.

Aged↗
PubMed2006

Assessment of genetic effects of polymorphisms in the MCP-1 gene on serum MCP-1 levels and myocardial infarction in Japanese.

BACKGROUND: Recently, the Framingham Heart Study reported that genetic variations in CCL2 influence serum levels of monocyte chemoattractant protein-1 (MCP-1) and the incidence of myocardial infarction (MI). The purpose of the present study was to investigate the possible involvement of CCL2 in the pathogenesis of atherosclerosis and MI in Japanese. METHODS AND RESULTS: Multiple regression analysis indicated that the MCP-1 levels were significantly influenced by various factors including age, body mass index, smoking, alcohol intake, high density lipoprotein-cholesterol, and systolic blood pressure. Moreover, the serum MCP-1 level was significantly correlated with intima - media thickness (p < 0.0001). However, this association disappeared when other clinical confounding factors were included in the analyses. Comprehensive analysis of common polymorphisms of CCL2 in a large community-based population and in subjects with MI found that the A(-2138)T polymorphism affected the serum MCP-1 level in a subgroup of subjects 65 years and older. However, no significant differences in the frequencies of any of the polymorphisms or haplotypes were found between subjects with and without MI. None of the polymorphisms in CCL2 affected carotid atherosclerosis. CONCLUSIONS: The serum MCP-1 level was a good surrogate marker of atherosclerosis in the present study population. Although genetic variations in CCL2 may have some influence on MCP-1 production, their influence does not seem to contribute appreciably to atherosclerosis in Japanese. The present results did not support the recently published findings from the Framingham Heart Study. The discrepancy between the 2 studies may be related to differences in confounding factors that contribute to MCP-1 levels and in the haplotype structure of the 2 populations.

Aged↗