J-shaped relationship between waist circumference and subsequent risk for Type 2 diabetes: an 8-year follow-up of relatively lean Japanese individuals

Dietary carbohydrate and the risk of type 2 diabetes: an updated systematic review and dose-response meta-analysis of prospective cohort studies

We did this study to clarify the association between carbohydrate intake and the risk of type 2 diabetes (T2D) and potential effect modification by geographical location. PubMed, Scopus and Web of Science were searched to find prospective cohort studies of dietary carbohydrate intake and T2D risk. A random-effects dose–response meta-analysis was performed to calculate the summary hazard ratios (HRs) and 95%CIs. The quality of cohort studies and the certainty of evidence was rated using the Newcastle–Ottawa Scale and GRADE tool, respectively. Eighteen prospective cohort studies with 29,229 cases among 607,882 participants were included. Thirteen studies were rated to have high quality, and five as moderate quality. The HR for the highest compared with the lowest category of carbohydrate intake was 1.02 (95%CI: 0.91, 1.15; I² = 67%, GRADE = low certainty). The HRs were 0.93 (95%CI: 0.82, 1.05; I² = 58%, n = 7) and 1.26 (95%CI: 1.11, 1.44; I² = 6%, n = 6) in Western and Asian countries, respectively. Dose–response analysis indicated a J shaped association, with the lowest risk at 50% carbohydrate intake (HR_50%: 0.95, 95%CI: 0.90, 0.99) and with risk increasing significantly at 70% carbohydrate intake (HR_70%: 1.18, 95%CI: 1.03, 1.35). There was no association between low carbohydrate diet score and the risk of T2D (HR: 1.14, 95%CI: 0.89, 1.47; I² = 90%, n = 5). Carbohydrate intake within the recommended 45–65% of calorie intake was not associated with an increased risk of T2D. Carbohydrate intake more than 70% calorie intake might be associated with a higher risk.

Risk Classification for Metabolic Syndrome and the Incidence of Cardiovascular Disease in Japan With Low Prevalence of Obesity: A Pooled Analysis of 10 Prospective Cohort Studies

Background

It is uncertain whether risk classification under the nationwide program on screening and lifestyle modification for metabolic syndrome captures well high‐risk individuals who could benefit from lifestyle interventions. We examined the validity of risk classification by linking the incidence of cardiovascular disease (CVD).

Methods and Results

Individual‐level data of 29 288 Japanese individuals aged 40 to 74 years without a history of CVD from 10 prospective cohort studies were used. Metabolic syndrome was defined as the presence of high abdominal obesity and/or overweight plus risk factors such as high blood pressure, high triglyceride or low high‐density lipoprotein cholesterol levels, and high blood glucose levels. The risk categories for lifestyle intervention were information supply only, motivation‐support intervention, and intensive support intervention. Sex‐ and age‐specific hazard ratios and population attributable fractions of CVD, which were also further adjusted to consider non–high density lipoprotein cholesterol levels, were estimated with reference to nonobese/overweight individuals, using Cox proportional hazard regression. Since the reference category included those with risk factors, we set a supernormal group (nonobese/overweight with no risk factor) as another reference. We documented 1023 incident CVD cases (565 men and 458 women). The adjusted CVD risk was 60% to 70% higher in men and women aged 40 to 64 years receiving an intensive support intervention, and 30% higher in women aged 65 to 74 years receiving a motivation‐support intervention, compared with nonobese/overweight individuals. The population attributable fractions in men and women aged 40 to 64 years receiving an intensive support intervention were 17.7% and 6.6%, respectively, while that in women aged 65 to 74 years receiving a motivation‐support intervention was 9.4%. Compared with the supernormal group, nonobese/overweight individuals with risk factors had similar hazard ratios and population attributable fractions as individuals with metabolic syndrome.

Conclusions

Similar CVD excess and attributable risks among individuals with metabolic syndrome components in the absence and presence of obesity/overweight imply the need for lifestyle modification in both high‐risk groups.

Frequency of consumption of balanced meals, bodyweight gain and incident risk of glucose intolerance in Japanese men and women: A cohort study

AIMS/INTRODUCTION

This cohort study assessed the risk for bodyweight gain and development of glucose intolerance based on the frequency of consumption of balanced meals including grain, fish or meat and vegetables.

MATERIALS AND METHODS

The participants (8,573 men, 3,327 women) were employees of a company in Japan. A self-administered questionnaire was used to evaluate the frequency of balanced meal consumption. Bodyweight changes and the incidence of glucose intolerance (glycated hemoglobin >6.0%) during the 3-year follow-up period were determined through annual health examinations.

RESULTS

The mean bodyweight change over a period of 3 years was 0.78 kg for men and 0.84 kg for women. A lower frequency of balanced meals was associated with a higher bodyweight gain for men (P for trend = 0.004), but not for women. During the study, 464 men and 115 women developed glucose intolerance. Overall, the frequency of balanced meals was not associated with the risk of glucose intolerance in either sex. However, the interaction between the frequency of balanced meals and degree of obesity had a significant effect on the incidence of glucose intolerance in men (P = 0.005), with less frequent consumption of balanced meals being associated with a higher risk for glucose intolerance among men with a BMI ≥25.0 kg/m2 (P for trend = 0.007).

CONCLUSIONS

A higher frequency of balanced meals, including grain, fish or meat and vegetable dishes - important components of healthy Japanese food - was associated with a lower risk of glucose intolerance in obese men, but not in non-obese men and women.

Adjustment for Waist Circumference Reveals a U-Shaped Association Between Glycated Hemoglobin Levels and Body Mass Index in Young Adults

OBJECTIVES

Body mass index (BMI) is used to assess adiposity worldwide. However, additional adjustment for waist circumference (WC), a surrogate marker of abdominal fat, may be capable of revealing a latent relationship between low body weight and glycated hemoglobin (A1C) concentration. Here, we investigated the relationship between A1C and BMI in young adults, adjusting for WC.

METHODS

We reviewed A1C, BMI, WC and other clinical data in a cross-sectional study of 26,475 apparently healthy Japanese people 20 to 39 years of age who were undergoing health check-ups.

RESULTS

Although the values of most serum parameters were high in subjects with a high BMI in both younger (20 to 29 years of age, n=10,810) and older subjects (30 to 39 years of age, n=15,665), A1C had a J-shaped relationship with BMI category in younger subjects, regardless of sex. A traditional linear model via a generalized linear model showed that in younger subjects, an inverse association of A1C level with BMI category (19 to 26.9 kg/m² vs. ≤18.9 kg/m²) was identified after adjustment for WC. This indicates positive associations between A1C and BMI categories of ≤18.9 (beta=0.06; p<0.0001), 19.0 to 20.9 (beta=0.03; p<0.01) and ≥27.0 kg/m² (beta=0.08; p<0.0001), in contrast to individuals with BMIs of 23.0 to 24.9 kg/m². Similarly, in older subjects, BMIs ≤18.9 kg/m² were associated with A1C levels but to a lesser extent (beta=0.04; p<0.05) than in younger subjects.

CONCLUSIONS

Additional adjustment of BMI for WC revealed a latent U-shaped association between A1C concentration and BMI, particularly in young adults; this deserves further investigation.

Physical Fitness Tests and Type 2 Diabetes Among Japanese: A Longitudinal Study From the Niigata Wellness Study

BACKGROUND

Simple physical fitness test can be a useful potential predictor of type 2 diabetes (T2DM). We examined the association between performances on simple physical fitness tests and the incidence of T2DM.

METHODS

This longitudinal study was conducted in 21,802 nondiabetic Japanese (6,649 women) aged 20 to 92 years, who underwent all physical fitness tests at baseline (April 2001 to March 2002). From April 2001 to March 2008, physical fitness tests, including grip strength, vertical jump, single-leg balance with eyes closed, forward bending, whole-body reaction time, and supine legs-up, were performed every year. Participants had physical fitness tests at least two times during the period. T2DM was also annually determined based on fasting blood glucose, glycated hemoglobin, and self-reported diabetes during the period. Discrete-time logit models were used to examine the influence of the serial level of each physical fitness test on the incidence of T2DM.

RESULTS

During the entire study period, 972 participants developed diabetes. Lower relative grip strength (grip strength/body weight) and single-leg balance performance were associated with a higher incidence of T2DM. For relative grip strength, as compared with the fourth quartile group, the odds ratios for other groups ranged from 1.16 to 1.56 (P for trend < 0.001). For single-leg balance, the odds ratios ranged from 1.03 to 1.49 (P for trend < 0.001).

CONCLUSION

The performance of a simple single-leg balance test as well as that of a grip strength test were negatively associated with the risk of T2DM among Japanese.

Diabetes Among Non-Overweight Individuals: an Emerging Public Health Challenge

PURPOSE OF REVIEW

Overweight and obesity are well-established risk factors for type 2 diabetes. However, a substantial number of individuals develop the disease at underweight or normal weight. In this review, we discuss the epidemiology of type 2 diabetes in non-overweight adults; pose questions about etiology, pathophysiology, diagnosis, and prognosis; and examine implications for prevention and treatment.

RECENT FINDINGS

In population-based studies, the prevalence of type 2 diabetes ranged from 1.4-10.9%. However, the prevalence of type 2 diabetes in individuals with BMI < 25 kg/m² ranged from 1.4-8.8%. In countries from Asia and Africa, the proportion of individuals with diabetes who were underweight or normal weight ranged from 24 to 66%, which is considerably higher than the US proportion of 10%. Impairments in insulin secretion, in utero undernutrition, and epigenetic alterations to the genome may play a role in diabetes development in this subgroup. A substantial number of individuals with type 2 diabetes, particularly those with recent ancestry from Asia or Africa, are underweight or normal weight. Future research should consist of comprehensive studies of the prevalence of type 2 diabetes in non-overweight individuals; studies aimed at understanding gaps in the mechanisms, etiology, and pathophysiology of diabetes development in underweight or normal weight individuals; and trials assessing the effectiveness of interventions in this population.

Type 2 diabetes: A 21st century epidemic

Around 415 million people around the world have diabetes (9% of adults), and the vast majority live in low- and middle-income countries. Over the next decade, this number is predicted to increase to 642 million people. Given that diabetes is a major cause of mortality, morbidity, and health care expenditures, addressing this chronic disease represents one of the greatest global health challenges of our time. The objectives of this article are three-fold: (1) to present data on the global burden of type 2 diabetes (which makes up 87-91% of the total diabetes burden), both in terms of prevalence and incidence; (2) to give an overview of the risk factors for type 2 diabetes, and to describe obesity and the developmental origins of disease risk in detail; and (3) to discuss the implications of the global burden and point out important research gaps.

Effect of Serum Cholesterol on Insulin Secretory Capacity: Shimane CoHRE Study

Objectives

Previous studies indicate that, in addition to the blood glucose level, the lipid level in the blood may affect functions of pancreatic beta cells. In this study, we aimed to examine whether there was a relationship between the serum level of total cholesterol (TC) and the insulin secretory capacity in healthy subjects.

Subjects and Methods

In participants of health examinations conducted from 2006 to 2010, we analyzed data from a total of 2,499 subjects (1,057 men and 1,442 women) after exclusion of individuals with dyslipidemia, thyroid dysfunction, diabetes, HbA1c≥6.5%, or fasting blood glucose≥126 mg/dL. Homeostasis model assessment for beta cell function (HOMA-beta) was utilized as a model representing the pancreatic beta cell function.

Results

Although the serum TC level had a positive correlation with HOMA-beta in a univariate correlation analysis, after adjustment by confounding factors in a multiple regression analysis, HOMA-beta had a negative correlation with TC. This was further confirmed in a multiple logistic regression analysis, showing that higher TC was an independent risk factor for decreased insulin secretory capacity (defined as HOMA-beta≤30%) together with higher age, lower BMI, lower TG, male sex and regular alcohol intake. After the participants were stratified by BMI into three groups, the effect of TC on HOMA-beta increased along with the increase in BMI, and it was highly significant in the highest tertile.

Conclusion

This cross-sectional study indicated that increased serum TC level might be related to the decrease of insulin secretory capacity in aged healthy population and that reduction of TC is more necessary in obese subjects to prevent diabetes.

Dietary carbohydrate intake, presence of obesity and the incident risk of type 2 diabetes in Japanese men

Aims/Introduction

The present cohort study assessed the risk among Japanese men for developing type 2 diabetes, based on the percentage of energy intake from carbohydrates and degree of obesity.

Participants and Methods

The participants were 2,006 male factory employees, and the macronutrient intake of each patient was measured using a self‐administered diet history questionnaire. The incidence of diabetes was determined in annual blood examinations over a 10‐year period.

Results

During the study, 232 participants developed diabetes. The crude incidence rates (/1,000 person‐years) for different levels of carbohydrate intake as a percentage of calories consumed (<50.0, 50.0–57.4, 57.5–65.0, >65.0% of energy intake) were 16.5, 14.4, 12.7 and 17.6. Overall, carbohydrate intake was not associated with the risk of diabetes. However, there was significant interaction between carbohydrate intake and degree of obesity on the incidence of diabetes (P for interaction = 0.024). Higher carbohydrate intake was associated with elevated risk for diabetes among participants with a body mass index ≥25.0 kg/m² (P for trend = 0.034). For obese participants, the multivariate‐adjusted hazard ratio for those with carbohydrate intakes >65% energy was 2.01 (95% confidence interval 1.08–3.71), which was significantly higher than that of participants with carbohydrate intakes 50.0–57.4% energy.

Conclusions

Higher carbohydrate intake was associated with higher risk of diabetes in obese participants, but not in non‐obese participants. Obese participants with carbohydrate intakes >65% energy should reduce their intakes to levels within the desirable carbohydrate energy proportion for Japanese (50–65% energy) to prevent development of type 2 diabetes.

Serum fructosamine and risk of type 2 diabetes mellitus among middle-age Finnish men: a 23-year population-based prospective study

The aim of this study was to determine whether serum fructosamine is associated with the risk of type 2 diabetes mellitus (T2DM) in a cohort of middle-age Finnish men. Fructosamine and other cardiometabolic risk factors were measured in a sample of 2,520 subjects from the population-based Kuopio Ischemic Heart Disease study. Associations between baseline fructosamine levels and risk of T2DM involved Cox-regression analyses, progressively adjusted for potential confounders and mediators. Mean baseline age and fructosamine levels were 53 years and 267 µmol/L, respectively. During a median follow-up of 23 years (interquartile range 18-25 years), 153 (6.1 %) new cases of T2DM were recorded. We observed an approximately "J-shaped" association between fructosamine values and T2DM risk, with a nadir at about 250 µmol/L. In subjects with fructosamine ≥250 µmol/L, the hazard ratios per 1 standard deviation (28 µmol/L) higher fructosamine levels resulted 1.20 (95 % CI 1.00-1.44; p = 0.046) in a model adjusted for age, body mass index, systolic blood pressure, serum high-density lipoprotein-cholesterol and family history T2DM. This association did not materially change upon further adjustment for C-reactive protein, physical activity, serum triglyceride and insulin resistance. However, no association was found when adjusting for baseline fasting plasma glucose (FPG). In this cohort of middle-age Finnish men, we found a "J-shaped" relationship between fructosamine and risk of T2DM, with a higher risk in subjects with baseline levels of fructosamine ≥250 µmol/L. Such an increased risk, however, was not independent from baseline FPG levels.

Sugar-sweetened beverage and diet soda consumption and the 7-year risk for type 2 diabetes mellitus in middle-aged Japanese men

PURPOSE

This cohort study investigated the association between sugar-sweetened beverage (SSB) and diet soda consumption and the incidence of type 2 diabetes in Japanese men.

METHODS

The participants were 2,037 employees of a factory in Japan. We measured consumption of SSB and diet soda using a self-administered diet history questionnaire. The incidence of diabetes was determined in annual medical examinations over a 7-year period. Hazard ratios (HRs) with 95 % confidence intervals (CIs) for diabetes were estimated after adjusting for age, body mass index, family history, and dietary and other lifestyle factors.

RESULTS

During the study, 170 participants developed diabetes. The crude incidence rates (/1,000 person-years) across participants who were rare/never SSB consumers, <1 serving/week, ≥ 1 serving/week and <1 serving/day, and ≥ 1 serving/day were 15.5, 12.7, 14.9, and 17.4, respectively. The multivariate-adjusted HR compared to rare/never SSB consumers was 1.35 (95 % CI 0.80-2.27) for participants who consumed ≥ 1 serving/day SSB. Diet soda consumption was significantly associated with the incident risk of diabetes (P for trend = 0.013), and multivariate-adjusted HRs compared to rare/never diet soda consumers were 1.05 (0.62-1.78) and 1.70 (1.13-2.55), respectively, for participants who consumed <1 serving/week and ≥ 1 serving/week.

CONCLUSIONS

Consumption of diet soda was significantly associated with an increased risk for diabetes in Japanese men. Diet soda is not always effective at preventing type 2 diabetes even though it is a zero-calorie drink.

Family history of diabetes, lifestyle factors, and the 7-year incident risk of type 2 diabetes mellitus in middle-aged Japanese men and women

Aims/Introduction

This cohort study of middle‐aged Japanese participants investigated the relationship between family history of diabetes, the incident risk of type 2 diabetes and the interaction of these variables with other factors.

Materials and Methods

Study participants were 3,517 employees (2,037 men and 1,480 women) of a metal products factory in Japan. Baseline health examinations included questions about medical history, physical examination, anthropometric measurements, questions about lifestyle factors, such as smoking, alcohol consumption and habitual exercise, and a self‐administered diet history questionnaire. Family history of diabetes was defined as having at least one‐first‐degree relative with diabetes. The incidence of diabetes was determined in annual medical examinations over a 7‐year period. Hazard ratios (HRs) for type 2 diabetes were estimated by Cox proportional hazards analysis.

Results

Of the 3,517 participants, 630 (18%) had a family history of diabetes mellitus. During the study, 228 participants developed diabetes. The age and sex‐adjusted HR for type 2 diabetes in participants with a family history of diabetes was 1.82 (95% confidence interval 1.36–2.43) as compared with those without a family history of diabetes. HRs did not change after adjustment for body mass index and lifestyle factors. We found no interactions with body mass index, insulin resistance, pancreatic β‐cell function or lifestyle factors.

Conclusions

Family history of diabetes was associated with the incident risk of diabetes, and these associations were independent of other risk factors, such as obesity, insulin resistance, and lifestyle factors in Japanese men and women.

Alcohol intake and the risk of hyperuricaemia: a 6-year prospective study in Japanese men

BACKGROUND AND AIMS

Since there is little information derived from prospective studies on the amount of alcohol drinking required to induce hyperuricaemia, we attempted to address this issue in a Japanese population.

METHODS AND RESULTS

A total of 3310 Japanese men aged 20-54 years that were free of hyperuricaemia were classified according to their alcohol intake per week at baseline. Incident hyperuricaemia, defined as >7.0 mg/dl and/or taking medication for hyperuricaemia, was assessed through annual heath examinations for 6 years after the baseline examination. During follow-up, 529 incident cases of hyperuricaemia occurred. There was a positive, dose-response relationship between alcohol intake and the risk of incident hyperuricaemia. The hazard ratio (95% confidence interval) for hyperuricaemia in drinkers compared with non-drinkers was 1.10 (0.85-1.42) for <10.0 drinks/week, 1.40 (1.07-1.84) for 10.0-19.9 drinks/week, 1.64 (1.23-2.21) for 20.0-29.9 drinks/week and 1.98 (1.40-2.80) for ≥30.0 drinks/week (one drink contained 11.5 g of ethanol) after adjusting for age, baseline serum uric acid, body mass index, smoking habits, exercise habits, serum creatinine, blood pressure, serum cholesterol and blood glucose. The fraction of hyperuricaemia in the population attributable to alcohol intake was 21.6%. A clear dose-response pattern was observed for both beer and sake, when the consumption of these two beverages was analysed separately.

CONCLUSION

Habitual alcohol intake significantly contributed to the development of hyperuricaemia in Japanese men, regardless of type of alcoholic beverage consumed. Therefore, it is essential to reduce excessive alcohol intake to prevent and manage hyperuricaemia.

Self-reported speed of eating and 7-year risk of type 2 diabetes mellitus in middle-aged Japanese men

OBJECTIVE

This cohort study investigated the association between eating speed and the incidence of type 2 diabetes in middle-aged Japanese men.

MATERIALS/METHODS

Participants were 2,050 male employees of a metal products factory in Japan. We measured self-reported categorical eating speed. The incidence of diabetes was determined in annual medical examinations over a 7-year period. The association between eating speed and the incidence of diabetes adjusted for multiple variables (age, family history of diabetes, smoking, alcohol drinking, habitual exercise, and presence of hypertension and hyperlipidemia) was evaluated using Cox proportional hazards models.

RESULTS

The prevalence of obesity (BMI≥25 kg/m(2)) across the categories of eating speed (slow, medium, and fast) was 14.6, 23.3, and 34.8%, respectively, and a faster eating speed was associated with a higher prevalence of obesity. During the study, 177 participants developed diabetes. Crude incidence rates (/1,000 person-years) across the three categories of eating speed were 9.9, 15.6, and 17.3, respectively. Multivariate-adjusted hazard ratios (95% CI) across the categories were 1.00 (reference), 1.68 (0.93-3.02), and 1.97 (1.10-3.55), respectively, and eating speed was associated with the risk of diabetes (p for trend=0.030). After further adjustment for BMI, a significant association was not observed.

CONCLUSIONS

Eating speed was associated with the incidence of diabetes. Since these associations were not significant after adjusting for BMI, eating speed may act via its effect on body weight. Eating speed is a controllable risk factor, and eating slowly could be an acceptable lifestyle intervention for the prevention of diabetes mellitus.

Magnesium intake and colorectal tumor risk: a case-control study and meta-analysis

BACKGROUND

Dietary magnesium might be related to colorectal tumor risk through the pivotal roles of magnesium in cellular metabolism, insulin resistance, and systemic inflammation.

OBJECTIVE

We evaluated the hypothesis of whether higher dietary magnesium intake is associated with reduced colorectal tumor risk.

DESIGN

A case-control study on colorectal adenomas (768 cases; 709 polyp-free control subjects) and a meta-analysis of colorectal adenomas (3 case-control studies) and carcinomas (6 prospective cohort studies) were conducted. Dietary magnesium was estimated from food-frequency questionnaires in the case-control study and most studies in the meta-analyses. Data analysis comprised multiple logistic regression analysis (case-control study) and fixed- and random-effects meta-analyses.

RESULTS

The case-control study showed a nonsignificant inverse association between dietary magnesium intake and risk of colorectal adenomas (OR for every 100-mg/d increase: 0.81; 95% CI: 0.62, 1.06). However, inverse associations were observed only in subjects with BMI (in kg/m²) ≥25, in subjects aged ≥55 y, and for advanced adenomas. Associations did not vary by the calcium-to-magnesium intake ratio. In the meta-analysis, every 100-mg/d increase in magnesium intake was associated with 13% lower risk of colorectal adenomas (OR: 0.87; 95% CI: 0.75, 1.00) and 12% lower risk of colorectal cancer (RR: 0.88; 95% CI: 0.81, 0.97).

CONCLUSIONS

Our findings support the hypothesis that higher intakes of dietary magnesium are associated with lower risk of colorectal tumors. The consumption of magnesium-rich foods may be a new avenue to explore further in the search for cancer-prevention strategies.

Impact of family history of diabetes on β-cell function and insulin resistance among Chinese with normal glucose tolerance

OBJECTIVE

This study investigated the impact of family history of diabetes (FHD) on β-cell function among Chinese with normal glucose tolerance.

RESEARCH DESIGN AND METHODS

A multistage, stratified, cluster random sampling method was used to select a provincially representative sample from Fujian Province. Eventually, a total of 1,183 subjects were entered into the analysis. Several indexes were used to assess the function of β cells, including homeostasis model assessment (HOMA) of insulin resistance (IR), HOMA of β cells, insulinogenic index (IGI), and disposition index.

RESULTS

Overweight, increased body mass index, higher low-density lipoprotein cholesterol, and higher total cholesterol (TC) were the dominant features of positive FHD (FHD(+)). The FHD(+) subjects had lower insulin sensitivity (P<0.05). FHD(+) subjects showed higher risk of IR after adjusting for other risk factors (odds ratio 1.523 [1.272-2.009]). However, there was no significant difference in insulin secretion between the two groups. With the use of the multiple linear regression model, waist circumference (WC) and triglycerides (TGs) were found to be independent risk factors of the decline of insulin sensitivity in FHD(+) subjects, and insulin sensitivity declined significantly (P<0.05) with the increase of WC and TGs. In addition, the offspring of fathers with diabetes (PT2D) were much older and had higher TC than those of mothers with diabetes (MT2D). After adjusting for gender of the parents, there was no difference between MT2D and PT2D on insulin sensitivity.

CONCLUSIONS

Inheritance if diabetes is associated with the decline of insulin sensitivity. In addition, insulin sensitivity declined with increasing WC and TG in FHD(+) subjects.

Independent association of waist circumference with hypertension and diabetes in African American women, South Carolina, 2007-2009

Introduction

Obesity is associated with hypertension and diabetes, which are independent risk factors for cardiovascular disease (CVD); 53% of African American women are obese. Of the approximately 44% of African American women who are hypertensive, more than 87% are overweight or obese. Additionally, more than twice as many African American women (13.1%) as white women (6.1%) have been diagnosed with type 2 diabetes. Obesity is usually measured using body mass index (BMI). However, abdominal adiposity may be more predictive of CVD risk than BMI. This study investigates the independent association of waist circumference with hypertension and diabetes in African American women.

Methods

As part of the Faith, Activity, and Nutrition (FAN) program, we recruited 843 African American women (mean age 53.8 y [SD, 14.1 y]) from African Methodist Episcopal churches. If a participant reported she had hypertension or had measured systolic blood pressure at or higher than 140 mm Hg or measured diastolic blood pressure at or higher than 90 mm Hg, she was classified as having hypertension. To assess increased health risks associated with waist circumference, we used the World Health Organization’s standards to categorize waist circumference as normal risk (waist circumference <80 cm), increased risk (waist circumference 80–88 cm), or substantially increased risk (waist circumference >88 cm). We used logistic regression models to test predictors of hypertension and diabetes.

Results

Of 843 study participants, 205 had diabetes and 545 were hypertensive. Women with a waist circumference of 88 cm or more were at increased risk for hypertension (odds ratio [OR] = 7.17, P < .002) and diabetes (OR = 6.99, P < .001). Associations remained after controlling for all variables (hypertension OR = 5.53, P < .001; diabetes, OR = 5.38, P < .001).

Conclusion

After controlling for all variables, waist circumference was independently associated with a 5-fold risk in hypertension and diabetes in African American women.

Dietary glycemic index and risk of type 2 diabetes mellitus in middle-aged Japanese men

This cohort study investigated the association between dietary glycemic index (GI), glycemic load (GL), and the incidence of type 2 diabetes mellitus in middle-aged Japanese men, and the effect of insulin resistance and pancreatic B-cell function on the association. Participants were 1995 male employees of a metal products factory in Japan. Dietary GI and GL were assessed using a self-administered diet history questionnaire. The incidence of diabetes was detected in annual medical examinations over a 6-year period. The association between GI, GL, and the incidence of diabetes was evaluated using Cox proportional hazards models. During the study, 133 participants developed diabetes. Age- and body mass index-adjusted hazard ratios across the GI quintiles were 1.00 (reference), 1.62, 1.50, 1.68, and 1.80; and those of GL were 1.00 (reference), 1.07, 1.48, 0.95, and 0.98. The hazard ratio for the highest GI quintile was significantly greater than that for the lowest quintile. The influence of GI was more pronounced in the lowest insulin resistance subgroups. GI and pancreatic B-cell function were independently associated with the incidence of type 2 diabetes mellitus; participants with low B-cell function and the highest tertile of GI had the highest risk of diabetes. Dietary GI is associated with the incidence of diabetes in middle-aged Japanese men. GI and B-cell function were independently associated with incidence of diabetes.

High dietary intake of magnesium may decrease risk of colorectal cancer in Japanese men

Magnesium maintains genomic stability and is an essential cofactor for DNA synthesis and repair. Magnesium intake has been reported to be inversely associated with colorectal cancer (CRC) risk in Western populations. This study examined the association between dietary intake of magnesium and CRC risk in Japanese men and women aged 45-74 y. Data from 40,830 men and 46,287 women, at the 5-y follow-up of the Japan Public Health Center-based Prospective Study, who responded to a 138-item FFQ were used in this analysis. A total of 689 and 440 CRC events were observed during the mean follow-up of 7.9 and 8.3 y for men and women, respectively. When adjusted for potential confounders, the hazard ratio and 95% CI in the highest quintile of magnesium intake compared with the lowest quintile in men were 0.65 (95% CI, 0.40-1.03) for CRC (P-trend = 0.04), 0.48 (95% CI, 0.26-0.89) for colon cancer (P-trend = 0.01), and 0.97 (95% CI, 0.47-2.02) for rectal cancer (P-trend = 0.93). Borderline inverse associations were also observed in men who consumed alcohol regularly (P-trend = 0.07) or had a BMI <25 kg/m(2) (P-trend = 0.06). There were similar inverse associations for invasive colon cancer and distal colon cancer. There were no significant associations between magnesium intake and cancer risk in women. Higher dietary intake of magnesium may decrease the risk of CRC in Japanese men.

Diabetes progression from "high-normal" glucose in school teachers

OBJECTIVE

High-normal, the intermediate category between normal fasting glucose (NFG) and impaired fasting glucose (IFG), was introduced in the criteria of the disordered glucose metabolism in 2008. The aim of this study was to investigate the risk for future incidence of type 2 diabetes of the subjects with high-normal and to examine how other metabolic variables could be useful for their risk stratification.

METHODS

A historical cohort study was conducted from 2001 to 2008, inclusive, in 4,165 non-diabetic employees at public schools (2,229 men and 1,936 women; age 45.8+/-5.9 years, range 25-55 years). They were classified at baseline as NFG with fasting plasma glucose (FPG)<100 mg/dL, high-normal with FPG 100-109 mg/dL, and IFG with FPG 110-125 mg/dL. The incidence of type 2 diabetes (defined either by FPG > or = 126 mg/dL or by receiving treatments) was measured.

RESULTS

The cumulative incidence during a mean follow-up of 5.1 years were 16/3,364 (0.5%), 40/613 (6.5%), and 53/188 (28.2%) in subjects with NFG, high-normal, and IFG, respectively. Multivariate-adjusted odds ratios for the incidence were still significant both in high-normal and IFG compared to NFG. Body mass index (BMI) and alanine aminotransaminase (ALT) were associated with the incidence of type 2 diabetes independently of FPG categories (p<0.05).

CONCLUSION

The future incidence of type 2 diabetes in subjects with high-normal was significantly higher than in those with NFG in this population. BMI and ALT can improve risk stratification in high-normal subjects.