Midlife and Late-Life Blood Pressure and Dementia in Japanese Elderly

The associations between blood pressure and dementia have been inconclusive. We followed up a total of 668 community-dwelling Japanese individuals without dementia, aged 65 to 79 years, for 17 years and examined the associations of late-life and midlife hypertension with the risk of vascular dementia and Alzheimer disease using the Cox proportional hazards model. During the follow-up, 76 subjects experienced vascular dementia and 123 developed Alzheimer disease. The age- and sex-adjusted incidence of vascular dementia significantly increased with elevated late-life blood pressure levels (normal: 2.3, prehypertension: 8.4, stage 1 hypertension: 12.6, and stage 2 hypertension: 18.9 per 1000 person-years; P trend <0.001), whereas no such association was observed for Alzheimer disease ( P trend =0.88). After adjusting for potential confounding factors, subjects with prehypertension and stage 1 or stage 2 hypertension had 3.0-fold, 4.5-fold, and 5.6-fold greater risk of vascular dementia, respectively, compared with subjects with normal blood pressure. Likewise, there was a positive association of midlife blood pressure levels with the risk of vascular dementia but not with the risk of Alzheimer disease. Compared with those without hypertension in both midlife and late life, subjects with midlife hypertension had an ≈5-fold greater risk of vascular dementia, regardless of late-life blood pressure levels. Our findings suggest that midlife hypertension and late-life hypertension are significant risk factors for the late-life onset of vascular dementia but not for that of Alzheimer disease in a general Japanese population. Midlife hypertension is especially strongly associated with a greater risk of vascular dementia, regardless of late-life blood pressure levels.

Smoking cessation improves mortality in Japanese men: the Hisayama study

BACKGROUND

Although the smoking rate among Japanese men has been the highest in developed countries, the epidemiological evidence about whether smoking cessation can extend their lifespan is not well established.

METHODS

A total of 1083 Japanese men aged ≥40 years were classified by their smoking status and followed up prospectively for 18 years (1988-2006).

RESULTS

Current smoking was a significant risk factor for all-cause death: the multivariate-adjusted HRs of all-cause death for current smokers of 1-19, 20-39 and ≥40 cigarettes per day were 1.61 (95% CI 1.16 to 2.22), 1.56 (95% CI 1.08 to 2.23) and 3.15 (95% CI 1.59 to 6.24), respectively. Former smokers did not have an increased risk of all-cause death compared with never smokers. The excess risk of all-cause death for current smokers tended to decrease within 5 years after smoking cessation, eventually reaching a level almost equivalent to that of never smokers. The risk of cancer death decreased by 53% in subjects who had quit smoking for ≥10 years, while the risk of cardiovascular death decreased by 56% in subjects with the cessation period of <10 years.

CONCLUSIONS

Our findings suggest that even a modest smoking habit significantly increases the risk of death among Japanese men, and the risk of death diminishes soon after cessation of smoking. These results imply the importance of smoking cessation to extend life in Japanese men.

Apolipoprotein genotype for prediction of Alzheimer's disease in older Japanese: the Hisayama Study

OBJECTIVES

To estimate the effects of the apolipoprotein E (APOE)-ɛ4 allele on the development of dementia and to elucidate its usefulness in the risk prediction of dementia in Japanese.

DESIGN

Prospective cohort study.

SETTING

The Hisayama Study, in Japan.

PARTICIPANTS

Five hundred twenty-three participants with deoxyribonucleic acid samples from a population of 1,073 community-dwelling participants without dementia aged 60 to 79.

MEASUREMENTS

The risk estimates of the APOE-ɛ4 allele on the development of all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD).

RESULTS

During 17 years of follow-up, 136 participants developed dementia, 81 of whom had AD and 39 VaD. After adjusting for age, sex, education, smoking, alcohol intake, systolic blood pressure, use of antihypertensive agents, glycosylated hemoglobin, serum total cholesterol, body mass index, and regular exercise, the risks of all-cause dementia and AD were significantly higher in APOE-ɛ4 carriers than in noncarriers, but no such association was observed for VaD (all-cause dementia: hazard ratio (HR)=1.81, P=.004; AD: HR=3.42, P<.001; VaD: HR=1.08, P=.86). The area under the receiver operating characteristic curve was significantly greater when the APOE genotype was incorporated into a model with potential risk factors for AD (0.74 vs 0.68, P=.02). Other measures of model discrimination (net reclassification improvement: 0.18, P=.01; integrated discrimination improvement: 6.25, P<.001) also confirmed this improvement in AD risk assessment.

CONCLUSION

The APOE-ɛ4 allele is a risk factor for AD in the Japanese population. Information on APOE genotype improves AD risk assessment substantially beyond a model based on potential risk factors.

High serum bilirubin levels and diabetic retinopathy: the Hisayama Study

PURPOSE

To assess the association between serum total bilirubin levels and diabetic retinopathy prevalence in participants of the Hisayama Study who had diabetes and impaired glucose metabolism.

DESIGN

Population-based, cross-sectional study.

PARTICIPANTS

Of 3119 participants of the Hisayama Study Eye Examinations in 2007, Japan, 1672 aged ≥40 years with either diabetes or impaired glucose metabolism (defined by a 75-g oral glucose tolerance test) were enrolled in the present study.

METHODS

Diabetic retinopathy was assessed via ophthalmic examination after pupil dilatation. The presence and the severity of diabetic retinopathy were determined by grading of color fundus photographs using the modified Airlie House classification system. Association of diabetic retinopathy with serum bilirubin quartiles was assessed using logistic regression model adjusting for age and known risk factors for diabetic retinopathy.

MAIN OUTCOME MEASURES

Prevalent diabetic retinopathy.

RESULTS

Diabetic retinopathy was present in 70 of 1672 (4.2%) participants. The prevalence of diabetic retinopathy in persons with the highest bilirubin quartile (≥0.9 mg/dL) was 2.7%, compared with the prevalence of 3.4%, 5.1%, and 5.1% in those with the first (<0.6 mg/dL), second (0.6-0.69 mg/dL), and third quartiles (0.7-0.89 mg/dL). After adjusting for factors known to be associated with diabetic retinopathy, the prevalence was significantly lower among persons with the highest bilirubin quartile compared with those with the lowest quartile (odds ratio [OR], 0.25; 95% confidence interval [CI], 0.09-0.72) or compared with those in the 3 lower quartiles (OR, 0.25; 95% CI, 0.11-0.58).

CONCLUSIONS

Elevated serum bilirubin levels may be protective against diabetic retinopathy among persons with either diabetes or impaired glucose metabolism, independent of known risk factors for diabetic retinopathy.

Albuminuria as a risk factor for peripheral arterial disease in a general population: the Hisayama study

AIMS

To elucidate the relationship between albuminuria and the prevalence of peripheral arterial disease (PAD), and to examine the effect of albuminuria on the ability to assess the likelihood of PAD in a general Japanese population.

METHODS

In 3,061 community-dwelling subjects aged. 40 years, we investigated the association of urinary albumin-creatinine ratio (UACR) levels with the prevalence of PAD, defined as an ankle-brachial index < 0.9. The odds ratio for the presence of PAD was estimated using the logistic regression model. To compare the accuracy of the assessment for the likelihood of prevalent PAD between models adjusted for potential risk factors with and without UACR levels, the receiver operating characteristic (ROC) curves were plotted.

RESULTS

Overall, 1.47% of the study participants had PAD. The age- and sex-adjusted prevalence of PAD increased linearly for UACR levels of < 5.6, 5.6-10.8, 10.9-29.9, 30.0-300.0, and >300.0 mg/g, being 0.34, 0.80, 2.02, 2.50, and 2.53%, respectively (p for trend <0.001). The multivariate-adjusted odds ratio for the presence of PAD was 1.85 (95% confidence interval 1.12-3.06) for every 10-fold increment in UACR. The area under the ROC curve significantly increased when UACR levels were incorporated into a model with potential risk factors for PAD (0.80 vs. 0.77, p= 0.02).

CONCLUSION

Greater UACR levels are associated linearly with a higher prevalence of PAD, even within the normoalbuminuric range, in the general Japanese population, and combining UACR levels with potential risk factors substantially improves the performance to assess the likelihood of PAD.

Japan Renal Biopsy Registry: the first nationwide, web-based, and prospective registry system of renal biopsies in Japan

BACKGROUND

The Committee for the Standardization of Renal Pathological Diagnosis and the Working Group for Renal Biopsy Database of the Japanese Society of Nephrology started the first nationwide, web-based, and prospective registry system, the Japan Renal Biopsy Registry (J-RBR), to record the pathological, clinical, and laboratory data of renal biopsies in 2007.

METHODS

The patient data including age, gender, laboratory data, and clinical and pathological diagnoses were recorded on the web page of the J-RBR, which utilizes the system of the Internet Data and Information Center for Medical Research in the University Hospital Medical Information Network. We analyzed the clinical and pathological diagnoses registered on the J-RBR in 2007 and 2008.

RESULTS

Data were collected from 818 patients from 18 centers in 2007 and 1582 patients from 23 centers in 2008, including the affiliated hospitals. Renal biopsies were obtained from 726 native kidneys (88.8%) and 92 renal grafts (11.2%) in 2007, and 1400 native kidneys (88.5%) and 182 renal grafts (11.5%) in 2008. The most common clinical diagnosis was chronic nephritic syndrome (47.4%), followed by nephrotic syndrome (16.8%) and renal transplantation (11.2%) in 2007. A similar frequency of the clinical diagnoses was recognized in 2008. Of the native kidneys, the most frequent pathological diagnosis as classified by pathogenesis was immunoglobulin (Ig) A nephropathy (IgAN) both in 2007 (32.9%) and 2008 (30.2%). Among the primary glomerular diseases (except IgAN), membranous nephropathy (MN) was the most common disease both in 2007 (31.4%) and 2008 (25.7%).

CONCLUSIONS

In a cross-sectional study, the J-RBR has shown IgAN to be the most common disease in renal biopsies in 2007 and 2008, consistent with previous Japanese studies. MN predominated in the primary glomerular diseases (except for IgAN). The frequency of the disease and the clinical and demographic correlations should be investigated in further analyses by the J-RBR.

Prevention of type 2 diabetes in a primary healthcare setting: three-year results of lifestyle intervention in Japanese subjects with impaired glucose tolerance

Background

A randomized control trial was performed to test whether a lifestyle intervention program, carried out in a primary healthcare setting using existing resources, can reduce the incidence of type 2 diabetes in Japanese with impaired glucose tolerance (IGT). The results of 3 years' intervention are summarized.

Methods

Through health checkups in communities and workplaces, 304 middle-aged IGT subjects with a mean body mass index (BMI) of 24.5 kg/m² were recruited and randomized to the intervention group or control group. The lifestyle intervention was carried out for 3 years by public health nurses using the curriculum and educational materials provided by the study group.

Results

After 1 year, the intervention had significantly improved body weight (-1.5 ± 0.7 vs. -0.7 ± 2.5 kg in the control; p = 0.023) and daily non-exercise leisure time energy expenditure (25 ± 113 vs. -3 ± 98 kcal; p = 0.045). Insulin sensitivity assessed by the Matsuda index was improved by the intervention during the 3 years. The 3-year cumulative incidence tended to be lower in the intervention group (14.8% vs.8.2%, log-rank test: p = 0.097). In a sub-analysis for the subjects with a BMI > 22.5 kg/m², a significant reduction in the cumulative incidence was found (p = 0.027).

Conclusions

The present lifestyle intervention program using existing healthcare resources is beneficial in preventing diabetes in Japanese with IGT. This has important implications for primary healthcare-based diabetes prevention.

Trial registration number

UMIN000003136

[Genome-wide association study for ischemic stroke based on the Hisayama study]

Ischemic stroke is a major cause of death and disability, and occurs owing to a combination of multiple environmental and genetic risk factors. Although twin studies and family-based studies have suggested the existence of genetic risk factors for ischemic stroke, few candidate genes have been discovered. To identify genes for susceptibility to ischemic stroke, we performed a genome-wide association study using 52,608 single nucleotide polymorphism (SNP) markers. After comparison of allele frequencies between 1,112 patients with ischemic stroke and the same number of age- and sex-matched control subjects, who were selected from among the residents of the town of Hisayama, Japan, we identified three novel candidate genes for ischemic stroke: PRKCH (protein kinase C eta (PKCη)), AGTRL1 (apelin receptor), and ARHGEF10 (Rho guanine nucleotide exchange factor 10). In the functional analyses, we found that PKCη was expressed mainly in vascular endothelial cells and foamy macrophages in human atherosclerotic lesions, and that the kinase activity of PKCη was modified by a nonsynonymous SNP in PRKCH (rs2230500). We also clarified that functional SNPs in AGTRL1 (rs9943582) and ARHGEF10 (rs4376531) affected transcriptional activities owing to the different Sp1-binding affinities. In a 14-year follow-up cohort study of Hisayama residents, all of these SNPs were significantly associated with the development of ischemic stroke. Although the mechanisms of these genes in the pathogenesis of ischemic stroke are still to be elucidated, our findings might contribute to a better understanding of ischemic stroke in the future.

Effectiveness of the salivary occult blood test as a screening method for periodontal status

BACKGROUND

Community-based periodontal examinations are not popular despite the high prevalence of periodontal disease among adults. This study examines the effectiveness of a novel salivary occult blood test (SOBT) as a screening method for periodontal status.

METHODS

Comprehensive health examinations were conducted in adult residents aged ≥40 years in Hisayama, Fukuoka, Japan; 1,998 subjects, each with ≥20 teeth, were analyzed. A paper test strip was used to perform the SOBT and was followed by a periodontal examination. Results were ranked as negative or positive. Subjects with ≥15% of teeth with bleeding on probing (BOP) or ≥1 tooth with a probing depth (PD) ≥4 mm were defined as having a poor periodontal status. The relationship between the results of the SOBT and periodontal parameters and among other variables was examined.

RESULTS

The sensitivity and specificity of the SOBT in screening for poor periodontal status were 0.72 and 0.52, respectively. In a multivariate logistic regression analysis, the results of the SOBT were significantly associated with the proportion of teeth with BOP and the proportion of teeth with PD ≥4 mm, independent of age, sex, use of antihypertensive medication, use of antidiabetic medication or insulin therapy, and the number of decayed or filled teeth.

CONCLUSION

The SOBT may offer a simple screening method for periodontal status when a thorough periodontal examination is not possible, although it is not sufficiently specific to be a reasonable substitute for a periodontal examination.

Trends in prevalence of Alzheimer's disease and vascular dementia in a Japanese community: the Hisayama Study

OBJECTIVE

To examine secular trends in the prevalence of Alzheimer's disease (AD) and vascular dementia (VD) in a general Japanese population.

METHOD

Four cross-sectional examinations were conducted among residents of a Japanese community aged >or=65 in 1985, 1992, 1998 and 2005.

RESULTS

The age- and sex-adjusted prevalence of all-cause dementia significantly increased with time (6.0% in 1985, 4.4% in 1992, 5.3% in 1998 and 8.3% in 2005; P for trend = 0.002). A similar trend was observed for AD (1.1%, 1.3%, 2.3% and 3.8% respectively; P for trend < 0.001), while the age- and sex-adjusted prevalence of VD and other/unclassified dementia showed J-shaped patterns (for VD: 2.3%, 1.5%, 1.5% and 2.5%, respectively, P for trend = 0.82; for other/unclassified dementia: 2.6%, 1.7%, 1.5% and 2.0%, P for trend = 0.26). The prevalence of AD was likely to increase with time from 1985 to 2005 among subjects aged 75 or older. The ratio of the prevalence of VD to that of AD decreased with time (2.1 in 1985, 1.2 in 1992, 0.7 in 1998 and 0.7 in 2005).

CONCLUSION

Our findings suggest that the prevalence of all-cause dementia and AD significantly increased over the past two decades in the general Japanese population.

Insulin resistance is associated with the pathology of Alzheimer disease: the Hisayama study

OBJECTIVE

We examined the association between diabetes-related factors and pathology of Alzheimer disease (AD) to evaluate how diabetes affects the pathogenic process of AD.

METHODS

This study included specimens from a series of 135 autopsies of residents of the town of Hisayama in Fukuoka prefecture (74 men and 61 women) performed between 1998 and 2003, who underwent a 75-g oral glucose tolerance test in clinical examinations in 1988. We measured diabetes-related factors including fasting glucose, 2-hour post-load plasma glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) in 1988. Neuritic plaques (NPs) were assessed according to the Consortium to Establish a Registry for Alzheimer's Disease guidelines and neurofibrillary tangles (NFTs) were assessed according to Braak stage. The associations between each factor and AD pathology were examined by analysis of covariance and logistic regression analyses.

RESULTS

Higher levels of 2-hour post-load plasma glucose, fasting insulin, and HOMA-IR were associated with increased risk for NPs after adjustment for age, sex, systolic blood pressure, total cholesterol, body mass index, habitual smoking, regular exercise, and cerebrovascular disease. However, there were no relationships between diabetes-related factors and NFTs. Regarding the effects of APOE genotype on the risk of AD pathology, the coexistence of hyperglycemia and APOE epsilon4 increased the risk for NP formation. A similar enhancement was observed for hyperinsulinemia and high HOMA-IR.

CONCLUSION

The results of this study suggest that hyperinsulinemia and hyperglycemia caused by insulin resistance accelerate NP formation in combination with the effects of APOE epsilon4.

[Lifestyle-related diseases as risk factors for dementia]

In this article, we have reviewed the findings of prospective cohort studies throughout the world to examine influences of lifestyle-related diseases on the risks of total dementia, Alzheimer disease (AD), and vascular dementia (VD). In some cohort studies on elderly populations, diabetes was found to be consistently associated with the risk of VD, but was inconsistently associated with the risk of AD. A cohort study on the elderly residents of the town of Hisayama, Japan, revealed the significant associations between glucose intolerance and the risks of both VD and AD. Clinical and experimental evidence has indicated that glucose intolerance and diabetes induce dementia through various mechanisms such as atherosclerosis,microvascular disease, glucose toxicity, and impaired insulin metabolism. No cohort studies have indicated significant associations between late-life hypertension and the risk of AD, and only 1 study has revealed the significant influence of hypertension on the risk of VD in an elderly population. The Hisayama study revealed that late-life hypertension was a significant risk factor for the development of VD but not for AD. A few cohort studies have suggested the presence of significant associations between midlife hypertension and the risks of late-life AD and VD. Metabolic syndrome has been shown to be a risk factor for the development of cognitive impairment, but no prospective cohort studies have investigated the significant influence of this syndrome on the risk of AD or VD. Some cohort studies have examined the associations of hypercholesterolemia with the risk of AD, but the results were inconsistent. Further studies are required to resolve these issues.

[The Hisayama Study]

Two cross-sectional surveys of diabetes mellitus using a 75-g oral glucose tolerance test (OGTT) conducted in the town of Hisayama showed that the prevalence of diabetes and other glucose intolerance statuses steeply increased during a 14-year period. In a prospective study of Hisayama residents, who underwent the OGTT at baseline, the risks for the development of ischemic stroke in both sexes and coronary heart disease in women were significantly higher in subjects with diabetes than in those with normal glucose tolerance even after adjustment for other confounding factors, but such association was not seen for coronary heart disease in men. Additionally, we observed a synergistic effect between diabetes and metabolic syndrome for the development of ischemic stroke and coronary heart disease.

Circulating resistin is increased with decreasing renal function in a general Japanese population: the Hisayama Study

BACKGROUND

The purpose of this study is to investigate the relationship between serum resistin levels and chronic kidney disease (CKD).

METHODS

A total of 3192 community-dwelling subjects (1377 men, 1815 women), aged ≥40 years and without renal failure, were divided into four groups according to quartiles of serum resistin concentrations: ≤7.1, 7.2-9.9, 10.0-14.7 and ≥14.8 ng/mL. The associations of resistin levels with renal function status were examined cross-sectionally. The estimated glomerular filtration rate (eGFR) was calculated using the equation from the Modification of Diet in Renal Disease Study, and CKD was defined as an eGFR of <60 mL/min/1.73 m(2).

RESULTS

The age- and sex-adjusted mean values of eGFR decreased significantly with elevating quartiles of resistin (P for trend <0.001). The age- and sex-adjusted odds ratios (ORs) for the presence of CKD increased progressively with higher quartiles of resistin. This trend remained robust even after controlling for age, sex, body mass index, diabetes, homeostasis model assessment of insulin resistance (HOMA-IR), high-sensitivity C-reactive protein (hs-CRP), triglycerides, high-density lipoprotein and total cholesterol, hypertension, current smoking, current drinking, and regular exercise [second quartile: OR 1.44, 95% confidence interval (CI) 1.05-1.99; third quartile: OR 2.15, 95% CI 1.58-2.92; fourth quartile: OR 2.32, 95% CI 1.71-3.16; P for trend <0.001]. In stratified analyses, high resistin level (≥7.2 ng/mL) was a significant relevant factor in CKD, independent of HOMA-IR or hs-CRP level. Conclusion. Our findings suggest that elevated resistin level is significantly associated with the likelihood of CKD in the general Japanese population.

Trends in the prevalence of chronic kidney disease and its risk factors in a general Japanese population: the Hisayama Study

BACKGROUND

Chronic kidney disease (CKD) is increasingly recognized as a leading public health issue. However, there are limited data assessing secular trends in the prevalence of CKD in general Asian communities.

METHODS

We performed three repeated cross-sectional surveys of residents aged >or=40 years in 1974 [2118 subjects (participation rate, 81.2%)], 1988 [2741 subjects (80.9%)] and 2002 [3297 subjects (77.6%)] in a Japanese community. We compared the prevalence of CKD [one or both of proteinuria and estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2)] and potential risk factors among the three surveys.

RESULTS

The prevalence of CKD increased significantly with time in men (13.8% [95% confidence interval (95% CI), 11.4-16.2%] in 1974, 15.9% [95% CI, 13.6-18.2%] in 1988 and 22.1% [95% CI, 19.6-24.6%] in 2002; P for trend < 0.001), but not in women (14.3% [95% CI, 12.2-16.4%], 12.6% [95% CI, 10.9-14.3%] and 15.3% [95% CI, 13.4-17.2%]; P for trend = 0.97). The frequencies of individuals with CKD Stages 3-5 (eGFR < 60 mL/min/1.73 m(2)) increased over the three decades in both sexes. Despite the widespread use of antihypertensive agents, the proportions of individuals with CKD who reached blood pressure of <130/80 mmHg were only 27.0% in men and 47.5% in women. The frequency of metabolic disorders including diabetes, hypercholesterolaemia and obesity increased over the three decades in both sexes.

CONCLUSIONS

The prevalence of CKD increased significantly in men, but not in women over the last three decades in a general Japanese population. Our findings support the requirement for a comprehensive treatment for hypertension and metabolic disorders to reduce the burden of CKD.

Impact of metabolic syndrome compared with impaired fasting glucose on the development of type 2 diabetes in a general Japanese population: the Hisayama study

OBJECTIVE

We examined whether metabolic syndrome predicts incident type 2 diabetes more effectively than impaired fasting glucose (IFG) in a general Japanese population.

RESEARCH DESIGN AND METHODS

A total of 1,935 nondiabetic subjects aged 40-79 years were followed-up prospectively for a mean of 11.8 years.

RESULTS

During the follow-up, 286 subjects developed type 2 diabetes. Compared with those without metabolic syndrome, the multivariate-adjusted hazard ratio (HR) for incident type 2 diabetes was significantly higher in subjects of both sexes with metabolic syndrome, even after adjustment for confounding factors, age, family history of diabetes, total cholesterol, alcohol intake, smoking habits, and regular exercise (men: HR 2.58 [95% CI 1.85-3.59]; women: 3.69 [2.58-5.27]). The multivariate-adjusted HR of metabolic syndrome for type 2 diabetes was slightly lower in men and similar in women compared with that of IFG. The multivariate-adjusted HR for type 2 diabetes rose progressively as the number of metabolic syndrome components increased in both subjects with and without IFG. In stratified analysis, the multivariate-adjusted risk of type 2 diabetes was significantly higher in subjects with metabolic syndrome alone (2.37 [1.45-3.88]) or IFG alone (3.49 [2.57-4.74]) and markedly increased in subjects with both metabolic syndrome and IFG (6.76 [4.75-9.61]) than in subjects with neither metabolic syndrome nor IFG. Furthermore, the multivariate-adjusted risk for type 2 diabetes was also significantly higher in subjects with both metabolic syndrome and IFG than in those with either one alone (both P < 0.001).

CONCLUSIONS

Our findings suggest that metabolic syndrome significantly increases the risk of incident type 2 diabetes, independent of IFG, and is therefore a valuable tool to identify individuals at high risk of type 2 diabetes.

Impact of glucose tolerance status on development of ischemic stroke and coronary heart disease in a general Japanese population: the Hisayama study

BACKGROUND AND PURPOSE

Few studies have shown the association between glucose tolerance status defined by a 75-g oral glucose tolerance test and the development of different types of cardiovascular disease.

METHODS

A total of 2421 community-dwelling Japanese subjects aged 40 to 79 years who underwent the oral glucose tolerance test were followed up for 14 years.

RESULTS

In multivariable analysis, the risks of ischemic stroke in both sexes and coronary heart disease (CHD) in women were significantly higher in subjects with diabetes determined by the World Health Organization criteria than in those with normal glucose tolerance even after adjustment for other confounding factors, but such association was not seen for CHD in men (ischemic stroke: adjusted hazard ratio [HR]=2.54, P=0.002 in men; adjusted HR=2.02, P=0.03 in women; CHD: adjusted HR=1.26, P=0.47 in men; adjusted HR=3.46, P=0.002 in women). Similar associations were observed for fasting plasma glucose levels of >or=7.0 mmol/L (ischemic stroke: adjusted HR=2.15, P=0.03 in men; adjusted HR=2.10, P=0.045 in women; CHD: adjusted HR=1.29, P=0.47 in men; adjusted HR=3.83, P=0.003 in women) and for 2-hour postload glucose levels of >or=11.1 mmol/L (ischemic stroke: adjusted HR=2.71, P=0.003 in men; adjusted HR=2.19, P=0.03 in women; CHD: adjusted HR=1.58, P=0.16 in men; adjusted HR=4.44, P<0.001 in women). The age-adjusted incidences of ischemic stroke and CHD did not significantly increase in subjects with impaired fasting glycemia or impaired glucose tolerance in either sex.

CONCLUSIONS

Our findings suggest that diabetes is an independent risk factor for ischemic stroke in both sexes and CHD in women in the Japanese population.

Chronic pulmonary toxicity study of indium-tin oxide and indium oxide following intratracheal instillations into the lungs of hamsters

OBJECTIVES

The aim of this study was to clarify the chronic toxicological effects of indium-tin oxide (ITO) and indium oxide (In(2)O(3)) on laboratory animals.

METHODS

Male Syrian golden hamsters were intratracheally administered 3 mg/kg or 6 mg/kg of ITO particles, or 2.7 mg/kg or 5.4 mg/kg of In(2)O(3) particles, containing 2.2 mg/kg or 4.5 mg/kg of indium, twice a week, for 8 wk. Control hamsters were given vehicle of distilled water only. The hamsters were euthanized serially up to 78 wk after the final instillation and the toxicological effects were determined.

RESULTS

Body weight gain was significantly suppressed in the ITO 6 mg/kg-treated hamsters compared with the control group, but not in the ITO 3 mg/kg-treated or In(2)O(3)-treated hamsters. Relative lung weights among all the indium-treated groups were significantly increased compared to that in the control group throughout the observation period. The serum indium concentration among all the indium-treated groups gradually increased up to the end of the observation period. Histopathologically, foci of slight to severe pulmonary inflammatory response with diffuse alveolar or bronchiolar cell hyperplasia, expansion of the alveolar spaces and interstitial fibrotic proliferation were present in all the indium-treated hamsters and the severity of these lesions worsened with the passage of time. Lung benign adenomas were only manifest in 3 out of 15 of the ITO 6 mg/kg-treated hamsters.

CONCLUSIONS

The present results clearly demonstrate that ITO and In(2)O(3) particles caused chronic pulmonary toxicity when repeated intratracheal instillations were given to hamsters.