Kazuya Fujihara

Comparisons of the Strength of Associations With Future Type 2 Diabetes Risk Among Anthropometric Obesity Indicators, Including Waist-to-Height Ratio: A Meta-Analysis

The aim of this meta-analysis was to compare the association of waist-to-height ratio (WHtR) with risk of incident diabetes with the associations of 3 other conventional obesity indicators (body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR)) with risk of incident diabetes. Literature searches in MEDLINE (January 1950 to April 27, 2011) and EMBASE (January 1974 to April 27, 2011) were conducted for prospective studies that made it possible to estimate the relative risk of diabetes per 1-standard deviation increase in WHtR, in addition to the RR of BMI, WC, or WHR. Strength of the estimated pooled relative risk for a 1-standard deviation increase of each indicator (expressed as RR(WHtR), RR(BMI), RR(WC), and RR(WHR)) was compared with a bivariate random-effects model. Pooled relative risks of the 15 eligible studies with 6,472 diabetes cases were 1.62 (95% CI: 1.48, 1.78) for RR(WHtR), 1.55 (95% CI: 1.43, 1.69) for RR(BMI), 1.63 (95% CI: 1.49, 1.79) for RR(WC), and 1.52 (95% CI: 1.40, 1.66) for RR(WHR). WHtR had an association stronger than that of BMI (P<0.001) or WHR (P<0.001). The present meta-analysis showed that WHtR has a modestly but statistically greater importance than BMI and WHR in prediction of diabetes. Nevertheless, measuring height in addition to WC appeared to have no additional benefit.

Association between physical activity and risk of all-cause mortality and cardiovascular disease in patients with diabetes: a meta-analysis.

OBJECTIVE The association between habitual physical activity (PA) and lowered risk of all-cause mortality (ACM) and cardiovascular disease (CVD) has been suggested in patients with diabetes. This meta-analysis summarizes the risk reduction in relation to PA, focusing on clarifying dose-response associations. RESEARCH DESIGN AND METHODS Electronic literature searches were conducted for cohort studies that examined relative risk (RR) of ACM or CVD in relation to PA in patients with diabetes. For the qualitative assessment, RR for the highest versus the lowest PA category in each study was pooled with a random-effects model. We added linear and spline regression analyses to assess the quantitative relationship between increases in PA and ACM and CVD risk. RESULTS There were 17 eligible studies. Qualitatively, the highest PA category had a lower RR [95% CI] for ACM (0.61 [0.52–0.70]) and CVD (0.71 [0.60–0.84]) than the lowest PA category. The linear regression model indicated a high goodness of fit for the risk of ACM (adjusted R2 = 0.44, P = 0.001) and CVD (adjusted R2 = 0.51, P = 0.001), with the result that a 1 MET-h/day incrementally higher PA was associated with 9.5% (5.0–13.8%) and 7.9% (4.3–11.4%) reductions in ACM and CVD risk, respectively. The spline regression model was not significantly different from the linear model in goodness of fit (P = 0.14 for ACM risk; P = 0.60 for CVD risk). CONCLUSIONS More PA was associated with a larger reduction in future ACM and CVD risk in patients with diabetes. Nevertheless, any amount of habitual PA was better than inactivity.

Diabetes and Risk of Hearing Impairment in Adults: A Meta-Analysis

CONTEXT Recently, several studies have investigated the relationship between diabetes and hearing impairment, but results were inconsistent. OBJECTIVE Our objective was to compare the prevalence of hearing impairment between diabetic and nondiabetic adults. DATA SOURCES We performed a systematic literature search using MEDLINE (1950 to May 30, 2011) and EMBASE (1974 to May 30, 2011). STUDY SELECTION Cross-sectional studies were included if data on numbers of hearing-impaired and non-hearing-impaired cases with diabetes were presented. Hearing impairment was limited to that assessed by pure-tone audiometry that included at least 2 kHz of frequency range and was defined as progressive, chronic, sensorineural, or without specified cause. DATA EXTRACTION Two authors independently extracted relevant data. Odd ratios (ORs) of hearing impairment related to diabetes calculated in each study were pooled with the random-effects model. DATA SYNTHESIS Data were obtained from 13 eligible studies (20,194 participants and 7,377 cases). Overall pooled OR (95% confidence interval) of hearing impairment for diabetic participants compared with nondiabetic participants was 2.15 (1.72-2.68). OR was higher in younger participants (mean age, ≤60 yr) than in those over 60 yr among which the OR remained significant (2.61 and 1.58, P = 0.008). The strength of the association between diabetes and prevalence of hearing impairment was not significantly influenced by whether participants were matched for age and gender (P = 0.68) or whether participants chronically exposed to noisy environments were excluded (P = 0.19). CONCLUSIONS Current meta-analysis suggests that the higher prevalence of hearing impairment in diabetic patients compared with nondiabetic patients was consistent regardless of age.

Quantitative relationship between body weight gain in adulthood and incident type 2 diabetes: a meta-analysis.

This meta‐analysis quantified the risk of type 2 diabetes mellitus (T2DM) preceded by body weight (BW) gain in the general population. Systematic literature searches retrieved 15 eligible studies. The BW gain was divided into early weight‐gain, which was defined as BW gain from early adulthood (18–24 years of age) to cohort entry (≥25 years of age), and late weight‐gain, which was defined as BW gain from cohort entry. The pooled relative risk (RR; 95% confidence interval [CI]) of T2DM for an increment of BW gain standardized into a 5‐kg m−2 increment in the body mass index (BMI) was 3.07 (2.49–2.79) for early weight‐gain and 2.12 (1.74–2.58) for late weight‐gain. When limiting analysis to studies that concurrently examined T2DM risk for current BMI (defined in both groups as BMI at cohort entry), a larger magnitude of T2DM risk was revealed for early weight‐gain compared with current BMI (RR [95% CI], 3.38 [2.20–5.18] vs. 2.39 [1.58–3.62]), while there was little difference between late weight‐gain (RR [95% CI], 2.21 [1.91–2.56]) and current BMI (RR [95% CI], 2.47 [1.97–3.30]). The meta‐analysis suggested that BW gain was a quantifiable predictor of T2DM, as well as current obesity in adults. Particularly, BW gain in early rather than middle‐to‐late adulthood played an important role in developing T2DM.

Metabolically Healthy Obesity, Presence or Absence of Fatty Liver, and Risk of Type 2 Diabetes in Japanese Individuals: Toranomon Hospital Health Management Center Study 20 (TOPICS 20)

OBJECTIVE We investigated whether the metabolically healthy obese (MHO) phenotype was associated with an increased risk of the development of diabetes. If so, we aimed to determine what factors could explain this finding. DESIGN, SETTING, AND PARTICIPANTS Studied were 8090 Japanese individuals without diabetes. Metabolic health status was assessed by common clinical markers: blood pressure, triglycerides, high-density lipoprotein-cholesterol, and fasting glucose concentrations. The cutoff value for obesity or normal weight (NW) was a body mass index of 25.0 kg/m(2). RESULTS The 5-year incidence rate of diabetes was 1.2% (n = 58 of 4749) in metabolically healthy NW (MHNW) individuals, 2.8% (n = 20 of 719) in MHO individuals, 6.0% (n = 102 of 1709) in metabolically abnormal NW individuals, and 10.3% (n = 94 of 913) in metabolically abnormal obese individuals. Although MHO individuals had no or one metabolic factor, 47.8% had ultrasonographic fatty liver (FL). The MHO group had a significantly increased risk of diabetes compared with the MHNW group [multivariate adjusted odds ratio (OR) 2.23 (95% confidence interval [CI] 1.33, 3.75)], but this risk was attenuated after adjustment for FL. Compared with the MHNW/non-FL group, the risk of diabetes in the MHO/non-FL group was not significantly elevated [OR 1.01 (95% CI 0.35, 2.88)]. However, the MHO/FL and MHNW/FL groups had similarly elevated risks of diabetes [OR 4.09 (95% CI 2.20, 7.60) and 3.16 (1.78, 5.62), respectively]. CONCLUSIONS Almost half of the MHO participants had FL, which partially explained the increased risk of diabetes among the obese phenotypes. The presence of FL should be evaluated to assess whether an individual was actually in a metabolically benign state for the prediction of diabetes.

Screening for pre‐diabetes to predict future diabetes using various cut‐off points for HbA1c and impaired fasting glucose: the Toranomon Hospital Health Management Center Study 4 (TOPICS 4)

Diabet. Med. 29, e279‐e285 (2012)

Role of alcohol drinking pattern in type 2 diabetes in Japanese men: the Toranomon Hospital Health Management Center Study 11 (TOPICS 11)

BACKGROUND Findings of past studies on the effect of drinking patterns on diabetes risk have been inconsistent. OBJECTIVE We aimed to investigate the role of drinking frequency and usual quantity consumed in the development of type 2 diabetes. DESIGN Enrolled were 1650 Japanese men without diabetes (diabetes: fasting plasma glucose ≥7.0 mmol/L, glycated hemoglobin ≥6.5%, or self-reported clinician-diagnosed diabetes). Average alcohol consumption and 12 combinations of frequency and usual quantity per drinking occasion were assessed at the baseline examination. The absolute risk and HR for the development of diabetes were calculated. RESULTS During a mean follow-up period of 10.2 y, 216 individuals developed diabetes. Lifetime abstainers (n = 153) had a relatively low incidence of diabetes (9.1/1000 person-years), similar to moderate consumers (99-160 g ethanol/wk; 9.0/1000 person-years). Increasingly higher quantities of alcohol usually consumed per occasion increased the risk of diabetes regardless of drinking frequency. The lowest incidence rate of diabetes (8.5/1000 person-years) was associated with the consumption of <1 drink (<23 g ethanol) per occasion over ≥6 times/wk. Binge drinking (≥3 drinks per occasion) significantly increased the risk of future diabetes regardless of frequency (HR: 1.79; 95% CI: 1.17, 2.74) compared with <1 drink per occasion. CONCLUSIONS Among current drinkers, a drinking pattern of <1 drink per occasion regularly over 6 times within a week was associated with the lowest risk of developing diabetes. Usual quantity per drinking occasion was a more important determinant than was weekly drinking frequency in the association between alcohol consumption and risk of diabetes in Japanese men.

Longitudinal Trajectories of HbA1c and Fasting Plasma Glucose Levels During the Development of Type 2 Diabetes: The Toranomon Hospital Health Management Center Study 7 (TOPICS 7)

OBJECTIVE To describe the trajectory of HbA1c and glucose concentrations before the diagnosis of diabetes. RESEARCH DESIGN AND METHODS The study comprised 1,722 nondiabetic Japanese individuals aged 26–80 years. Fasting plasma glucose (FPG) and HbA1c were measured annually for a mean of 9.5 (SD 1.8) years. RESULTS Diabetes occurred in 193 individuals (FPG ≥7.0 mmol/L, self-reported clinician-diagnosed diabetes, or HbA1c ≥6.5%). Mean HbA1c values were >5.6% each year before diagnosis in diabetes cases. Mean HbA1c (5.69% [95% CI 5.50–5.88]) was higher in the 21 individuals who developed diabetes 10 years after the baseline examination than in nondiabetic individuals after 10 years (5.27% [5.25–5.28]). From 3 years to 1 year prediagnosis, HbA1c increased 0.09% (SE 0.01)/year, reaching 5.90% (5.84–5.96) 1 year prediagnosis. In the entire group, marked increases in HbA1c of 0.3% (SE 0.05%)/year and FPG of 0.63 (0.07) mmol/L/year predicted diabetes. CONCLUSIONS HbA1c trajectory increased sharply after gradual long-term increases in diabetic individuals.

High normal HbA1c levels were associated with impaired insulin secretion without escalating insulin resistance in Japanese individuals: the Toranomon Hospital Health Management Center Study 8 (TOPICS 8)

Diabet. Med. 29, 1285–1290 (2012)

Impact of psychological stress caused by the Great East Japan Earthquake on glycemic control in patients with diabetes

We examined the relationship between psychological stress and the worsening of glycemic control in diabetic patients at the time of the Great East Japan Earthquake. HbA1c levels in diabetic patients before and after the disaster were evaluated with the General Health Questionnaire (GHQ) and other questions including those on changes in diet, exercise, psychological stress and drug intake in 320 consecutive diabetic patients who had been followed in a diabetes clinic. Logistic regression analysis revealed that the total GHQ scores (odds ratio [OR] 1.03 [95% confidence interval 1.01-1.06]; p<0.01) and interruption of drug intake (OR 4.48 [1.57-12.7]; p=0.01) were independently associated with worsening of glycemic control defined as an increase in the HbA1c level equal to or greater than 0.5%. Among the scores on the GHQ, those for somatic symptoms (OR 1.18 [1.01-1.38]; p=0.03) and sleep disturbances or anxiety (OR 1.26 [1.08-1.46]; p<0.01) were independently associated with glycemic control. These results suggest that psychological stress during a disaster has independent effects on worsening of glycemic control.