Misuzu Fujita

Lower frequency of daily teeth brushing is related to high prevalence of cardiovascular risk factors.

This study sought to investigate relationships between frequency of daily teeth brushing and prevalences of diabetes mellitus, hypertension and dyslipidemia. Subjects were 54,551 residents of Chiba City, Japan (20,155 men and 34,396 women) who underwent routine health examinations in 2004. Diabetes mellitus was defined as a fasting plasma glucose level ≥126 mg/dl or a non-fasting plasma glucose level ≥200 mg/dl and/or receiving treatment for diabetes. Hypertension was defined as systolic blood pressure (SBP) ≥140 mmHg, diastolic blood pressure (DBP) ≥90 mmHg and/or receiving treatment for hypertension. Dyslipidemia was defined according to the two criteria: high triglyceride and/or low high density lipoprotein cholesterol (TG ≥ 150 mg and/or HDL-C < 40 mg/dl), and high total cholesterol (TC ≥ 220 mg/dl). According to Pearson’s chi-square tests and logistic regression analysis adjusted for age, BMI, smoking habit, alcohol consumption and daily walking time, lower frequency of teeth brushing is related to higher prevalences of diabetes mellitus, hypertension and high TG and/or low HDL-C, in both men and women. Total cholesterol status, however, showed no significant relationship. Maintaining good oral hygiene by regular teeth brushing may prevent type 2 diabetes, hypertension and dyslipidemia.

Predictive Power of a Body Shape Index for Development of Diabetes, Hypertension, and Dyslipidemia in Japanese Adults: A Retrospective Cohort Study

Background/Objectives Recently, a body shape index (ABSI) was reported to predict all-cause mortality independently of body mass index (BMI) in Americans. This study aimed to evaluate whether ABSI is applicable to Japanese adults as a predictor for development of diabetes, hypertension, and dyslipidemia. Subjects/Methods We evaluated the predictive power of ABSI in a retrospective cohort study using annual health examination data from Chiba City Hall in Japan, for the period 2008 to 2012. Subjects included 37,581 without diabetes, 23,090 without hypertension, and 20,776 without dyslipidemia at baseline who were monitored for disease incidence for 4 years. We examined the associations of standardized ABSI, BMI, and waist circumference (WC) at baseline with disease incidence by logistic regression analyses. Furthermore, we conducted a case-matched study using the propensity score matching method. Results Elevated BMI, WC, and ABSI increased the risks of diabetes and dyslipidemia [BMI-diabetes: odds ratio (OR) = 1.26, 95% confidence interval (95%CI) = 1.20−1.32; BMI-dyslipidemia: OR = 1.15, 95%CI = 1.12−1.19; WC-diabetes: OR = 1.24, 95%CI = 1.18−1.31; WC-dyslipidemia: OR = 1.15, 95%CI = 1.11−1.19; ABSI-diabetes: OR = 1.06, 95%CI = 1.01−1.11; ABSI-dyslipidemia: OR = 1.04, 95%CI = 1.01−1.07]. Elevated BMI and WC, but not higher ABSI, also increased the risk of hypertension [BMI: OR = 1.32, 95%CI = 1.27−1.37; WC: OR = 1.22, 95%CI = 1.18−1.26; ABSI: OR = 1.00, 95%CI = 0.97−1.02]. Areas under the curve (AUCs) in regression models with ABSI were significantly smaller than in models with BMI or WC for all three diseases. In case-matched subgroups, the power of ABSI was weaker than that of BMI and WC for predicting the incidence of diabetes, hypertension, and dyslipidemia. Conclusions Compared with BMI or WC, ABSI was not a better predictor of diabetes, hypertension, and dyslipidemia in Japanese adults.

Sex and age differences in the effect of obesity on incidence of hypertension in the Japanese population: A large historical cohort study.

Elevated risk of death from any cause and stroke associated with high body mass index (BMI) values decline with aging. However, it is not clear whether the effect of obesity on the incidence of hypertension varies by sex or age. Cox regression analyses were performed using a large historical cohort composed of 6803 men and 22,800 women. In the final model, which included the main effect (sex, age, and BMI), all two-way interactions (sex*age, sex*BMI, and age*BMI), a three-way interaction (sex*age*BMI), and adjusted variables determined by backward elimination, the three-way interaction and two of the two-way interactions (age*sex and age*BMI) were not significant; the remaining two-way interaction between sex and BMI was significant (P = .016). In the next step, the effect of BMI on the incidence of hypertension stratified by sex was evaluated. Hazard ratios (HRs) were significantly higher for BMI 27.0 to <29.0 and ≥29.0 kg/m(2) than for the HR for BMI 21.0 to <23.0 kg/m(2) in women (HR, 1.45; 95% confidence interval [CI], 1.32-1.59 and HR, 1.46; 95% CI, 1.29-1.65, respectively), but not in men (HR, 1.14; 95% CI, 0.98-1.33 and HR, 1.01; 95% CI, 0.77-1.32, respectively). The effect of obesity on the incidence of hypertension is stronger in women than in men.

Effect of Obesity on Incidence of Type 2 Diabetes Declines with Age Among Japanese Women

Aims: The present study sought to investigate whether the effect of obesity on the incidence of type 2 diabetes varies with age among Japanese. Methods: Employing two independent cohorts, one in Chiba City from 1994 to 2005 and the other in Kashiwa City from 2002 to 2006, the combined effect of body mass index (BMI) and age on the incidence of type 2 diabetes was evaluated by Cox regression analysis. A total of 37,564 and 26,959 subjects were enrolled in the cohorts and the follow-up rate was 94.7% and 93.3%, respectively. Results: In the Chiba cohort, the hazard ratio for incidence of type 2 diabetes was significantly higher in obese subjects (25.0 kg/m2 ≤ BMI) than in normal weight subjects (18.5 kg/m2 ≤ BMI < 25.0 kg/m2) across all age groups, with the highest hazard ratio observed in the youngest group aged 40–59 years. In the Kashiwa cohort, the hazard ratio was also significantly higher in obese subjects than in normal weight subjects in men aged 40–59 and 70–79 years and in women aged 40–59 years. Analysis for the interaction between age groups and obese subjects versus normal weight subjects revealed significant weakening of the effect of obesity in women in both cohorts in subjects aged 60–69 and 70–79 years compared to younger subjects aged 40–59 years. In men, however, a significant weakening of the effect was observed only in subjects aged 60–69 years in the Chiba cohort. The interaction between four BMI categories including an extremely obese group (30.0 kg/m2 ≤ BMI) and age category was significant in women (P < 0.001) but not in men (P = 0.113) in the Chiba cohort. Conclusion: Based on data from the two independent cohorts, the effect of obesity on the incidence of type 2 diabetes was found to decline with age in Japanese women but not in men.

Association of gamma-glutamyltransferase with incidence of type 2 diabetes in Japan:

The aim of this research was to examine the association of gamma-glutamyltransferase (GGT) and its interactions with alcohol consumption (alcohol), body mass index (BMI) and/or alanine aminotransferase (ALT) on the incidence of type 2 diabetes (DM) in Japan. Data from annual health examinations obtained from 1995 to 2005 were analyzed. The total number of subjects in this cohort was 39,563. Hazard ratios (HRs) were calculated by Cox regression analysis. GGT levels were positively associated with the incidence of DM in both men and women, after adjustment for several variables, including alcohol, BMI and ALT. Among women, the association was stronger in non-drinkers than in drinkers due to a significant interaction of GGT and alcohol. In non-drinkers, the HRs of the third and fourth GGT quartiles in women and the fourth GGT quartile in men were significantly higher than those of the first GGT quartile. The association between BMI and the incidence of DM was enhanced by increased GGT levels in women. When GGT levels were in the second to fourth quartiles, the HRs of obese subjects were significantly higher than those of underweight subjects. Conversely, obesity was no longer a significant risk factor for DM when GGT level was in the first quartile. Increased GGT levels were associated with the development of DM after adjustment for several possible confounding factors. The association between GGT and DM in non-drinkers was significantly stronger than that in drinkers. Furthermore, in women, obesity is no longer a risk factor for DM when GGT level is low.

Income Related Inequality of Health Care Access in Japan: A Retrospective Cohort Study.

The purpose of this retrospective cohort study was to analyze the association between income level and health care access in Japan. Data from a total of 222,259 subjects (age range, 0–74 years) who submitted National Health Insurance claims in Chiba City from April 2012 to March 2014 and who declared income for the tax period from January 1 to December 31, 2012 were integrated and analyzed. The generalized estimating equation, in which household was defined as a cluster, was used to evaluate the association between equivalent income and utilization and duration of hospitalization and outpatient care services. A significant positive linear association was observed between income level and outpatient visit rates among all age groups of both sexes; however, a significantly higher rate and longer period of hospitalization, and longer outpatient care, were observed among certain lower income subgroups. To control for decreased income due to hospitalization, subjects hospitalized during the previous year were excluded, and the data was then reanalyzed. Significant inverse associations remained in the hospitalization rate among 40–59-year-old men and 60–69-year-old women, and in duration of hospitalization among 40–59 and 60–69-year-olds of both sexes and 70–74-year-old women. These results suggest that low-income individuals in Japan have poorer access to outpatient care and more serious health conditions than their higher income counterparts.

Validity assessment of self-reported medication use by comparing to pharmacy insurance claims

Objectives In Japan, an annual health check-up and health promotion guidance programme was established in 2008 in accordance with the Act on Assurance of Medical Care for the Elderly. A self-reported questionnaire on medication use is a required item in this programme and has been used widely, but its validity has not been assessed. The aim of this study was to evaluate the validity of this questionnaire by comparing self-reported usage to pharmacy insurance claims. Setting This is a population-based validation study. Self-reported medication use for hypertension, diabetes and dyslipidaemia is the evaluated measurement. Data on pharmacy insurance claims are used as a reference standard. Participants Participants were 54 712 beneficiaries of the National Health Insurance of Chiba City. Primary and secondary outcome measures Sensitivity, specificity and κ statistics of the self-reported medication-use questionnaire for predicting actual prescriptions during 1 month (that of the check-up) and 3 months (that of the check-up and the previous 2 months) were calculated. Results Sensitivity and specificity scores of questionnaire data for predicting insurance claims covering 3 months were, respectively, 92.4% (95% CI 91.9 to 92.8) and 86.4% (95% CI 86.0 to 86.7) for hypertension, 82.6% (95% CI 81.1 to 84.0) and 98.5% (95% CI 98.4 to 98.6) for diabetes, and 86.2% (95% CI 85.5 to 86.8) and 91.0% (95% CI 90.8 to 91.3) for dyslipidaemia. Corresponding κ statistics were 70.9% (95% CI 70.1 to 71.7), 77.1% (95% CI 76.2 to 77.9) and 69.8% (95% CI 68.9 to 70.6). The specificity was significantly higher for questionnaire data covering 3 months compared with data covering 1 month for all 3 conditions. Conclusions Self-reported questionnaire data on medication use had sufficiently high validity for further analyses. Item responses showed close agreement with actual prescriptions, particularly those covering 3 months.

High saturated fatty acid intake induces insulin secretion by elevating gastric inhibitory polypeptide levels in healthy individuals

Insulin resistance is central to the etiology of the metabolic syndrome cluster of diseases. Evidence suggests that a high-fat diet is associated with insulin resistance, which may be modulated by dietary fatty acid composition. We hypothesized that high saturated fatty acid intake increases insulin and gastric inhibitory polypeptide (GIP) secretion. To clarify the effect of ingested fatty acid composition on glucose levels, we conducted an intervention study to investigate the insulin and plasma GIP responses in 11 healthy women, including a dietary control. Subjects were provided daily control meals (F-20; saturated fatty acids/monounsaturated fatty acids/polyunsaturated fatty acids [S/M/P] ratio, 3:4:3) with 20 energy (E) % fat, followed by 2 isoenergetic experimental meals for 7 days each. These meals comprised 60 E% carbohydrate, 15 E% protein, and 30 E% fat (FB-30; high saturated fatty acid meal; S/M/P, 5:4:1; F-30: reduced saturated fatty acid meal; S/M/P, 3:4:3). On the second day of the F-20 and the last day of F-30 and FB-30, blood samples were taken before and 30, 60, and 120 minutes after a meal tolerance test. The plasma glucose responses did not differ between F-20 and FB-30 or F-30. However, insulin levels were higher after the FB-30 than after the F-20 (P < .01). The GIP response after the FB-30 was higher than that after the F-30 (P < .05). In addition, the difference in the incremental GIP between FB-30 and F-30 correlated significantly and positively with that of the insulin. These results suggest that a high saturated fatty acid content stimulates postprandial insulin release via increased GIP secretion.

Income-Related Inequalities in Access to Dental Care Services in Japan

Background: This study aimed to evaluate whether income-related inequalities in access to dental care services exist in Japan. Methods: The subjects included beneficiaries of the National Health Insurance (NHI) in Chiba City, Japan, who had been enrolled from 1 April 2014 to 31 March 2015. The presence or absence of dental visits and number of days spent on dental care services during the year were calculated using insurance claims submitted. Equivalent household income was calculated using individual income data from 1 January to 31 December 2013, declared for taxation. Results: Of the 216,211 enrolled subjects, 50.3% had dental care during the year. Among those with dental visits, the average number of days (standard deviation) spent on dental care services per year was 7.7 (7.1). Low income was associated with a decreased rate of dental care utilization regardless of age and sex. However, there was a significant inverse linear association between the number of days spent on dental care services and income levels for both sexes. Conclusions: There were income-related inequalities in access to dental care services, regardless of the age group or sex, within the Japanese universal health insurance system.

Impact of geographic accessibility on utilization of the annual health check-ups by income level in Japan: A multilevel analysis

Although both geographic accessibility and socioeconomic status have been indicated as being important factors for the utilization of health care services, their combined effect has not been evaluated. The aim of this study was to reveal whether an income-dependent difference in the impact of geographic accessibility on the utilization of government-led annual health check-ups exists. Existing data collected and provided by Chiba City Hall were employed and analyzed as a retrospective cohort study. The subjects were 166,966 beneficiaries of National Health Insurance in Chiba City, Japan, aged 40 to 74 years. Of all subjects, 54,748 (32.8%) had an annual health check-up in fiscal year 2012. As an optimal index of geographic accessibility has not been established, five measures were calculated: travel time to the nearest health care facility, density of health care facilities (number facilities within a 30-min walking distance from the district of residence), and three indices based on the two-step floating catchment area method. Three-level logistic regression modeling with random intercepts for household and district of residence was performed. Of the five measures, density of health care facilities was the most compatible according to Akaike’s information criterion. Both low density and low income were associated with decreased utilization of the health check-ups. Furthermore, a linear relationship was observed between the density of facilities and utilization of the health check-ups in all income groups and its slope was significantly steeper among subjects with an equivalent income of 0.00 yen than among those with equivalent income of 1.01–2.00 million yen (p = 0.028) or 2.01 million yen or more (p = 0.040). This result indicated that subjects with lower incomes were more susceptible to the effects of geographic accessibility than were those with higher incomes. Thus, better geographic accessibility could increase the health check-up utilization and also decrease the income-related disparity of utilization.