Sex specific incidence rates of type 2 diabetes and its risk factors over 9 years of follow-up: Tehran Lipid and Glucose Study

Estimated reductions in type 2 diabetes burden through nutrition policies in AZAR cohort population: A PRIME microsimulation study for primary health care

Background

Given the impact of high intake of sugar-sweetened beverages on type 2 diabetes, intervention to reduce their consumption can be a top priority for any health system. Thus, the purpose of the present study is to simulate the impact of policy options related to reduce consumption of sugar-sweetened beverages (SSBs) on the prevalence and mortality of type 2 diabetes in Iranian men and women.

Methods

A discrete event simulation (DES) model was used to predict the effect of several policy options on the prevalence and death from type 2 diabetes in Azar Cohort Databases. Population age- and sex-specific prevalence and incidence rate of diagnosed diabetes were derived from the national health data. The Preventable Risk Integrated Model (PRIME) model was used for coding the input parameters of simulation using R and Python software.

Results

The prevalence and mortality rate of type 2 diabetes under the scenario of reduced consumption of SSBs indicated that the highest and the lowest prevalence and mortality rates of type 2 diabetes for men and women were related to no policy condition and replacing SSBs with healthy drinks, like water, respectively. Also, the maximum "number of deaths postponed/ prevented" from type 2 diabetes was related to replacing SSBs with water (n=2015), and an integration of reformulation and applying 10% tax on SSBs (n=1872), respectively.

Conclusion

Simulating the effect of different policy options on reducing the consumption of SSBs showed "replacing of SSBs with water" as the most effective policy option in Iranian setting.

The association of ideal cardiovascular health metrics and incident hypertension among an urban population of Iran: a decade follow-up in Tehran Lipid and Glucose Study

We aimed to determine the association between ideal cardiovascular health metrics (ICVHM) and the incidence of hypertension among Iranian adults. The study population included 5409 Iranian adults aged ≥20 years (2088 men) without hypertension (applying the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) guideline) at baseline. The ICVHM was defined according to the AHA's 2020 impact goals, excluding total cholesterol was replaced by non-HDL cholesterol (non-HDL-C). Multivariable Cox proportional hazards regression analysis was done to estimate the hazard ratios (HRs) for ICVHM both as continuous and categorical variables. During a median 8.5-year follow-up, 2972 new cases of hypertension were identified (men: 1,287). Non-HDL-C < 130 mg/dL in men [HR (95% CI): 0.75(0.65-0.86)] and fasting plasma glucose(FPG) < 100 mg/dL in women[HR (95% CI): 0.79(0.64-0.97)], and among both genders, being normal/overweigth status (compared to obese) and blood pressure <120/80 mmHg were associated with a lower risk for hypertension. Additionally, in both gender, a 1-point increase in the number of global ICVHM decreased the risk of hypertension by more than 10%, and having ≥5 vs. <2 ICVHM, were associated with a lower risk of hypertension by 30% (all p values < 0.05). Applying the JNC 7 guideline, the association between ICVHM, with incident hypertension, were generally similar. Having a higher number of ICVHM was associated with a lower risk of incident hypertension, using both 2017 ACC/AHA and JNC 7 guidelines, mostly attributable to keeping the ideal status of body mass index, non-HDL-C, and FPG.

The effect of metformin therapy on serum thyrotropin and free thyroxine concentrations in patients with type 2 diabetes: a meta-analysis

Type 2 diabetes and thyroid function disorders are two common chronic endocrine disorders with the high prevalence in various populations. Metformin is well established as the first-line drug therapy for managing diabetes mellitus. In this meta-analysis, we aimed to determine the effect of metformin on serum TSH and FT4 concentrations in patients with type 2 diabetes. We searched PubMed, Scopus, web of science, Cochrane library, and google scholar to collect information on the effect of metformin on serum TSH and FT4 levels. Demographic and clinical information and serum TSH and FT4 concentrations before and after metformin treatment were extracted. Studies on patients over 18 years of age were included. A total of 11 studies including 1147 patients were selected for the final analysis. In hypothyroid patients, the TSH level decreased significantly after treatment with metformin (Hedges's g:1.55, 95%CI 0.93-2.16, p-value < 0.001); FT4 level increased slightly after taking metformin, but the increase was not significant (Heddges's g: - 0.30, 95%CI  - 0.90,0.31, p-value = 0.34). In euthyroid subjects, the slight decrease found in TSH and FT4 concentrations was not statistically significant. Metformin reduces TSH levels in hypothyroid patients; however, it has no effect on TSH levels in euthyroid patients. Metformin does not affect serum FT4 levels in euthyroid and hypothyroid patients.

Resting heart rate and the risk of incident type 2 diabetes mellitus among non-diabetic and prediabetic Iranian adults: Tehran lipid and glucose study

BACKGROUND

Resting heart rate (RHR) has been found to be a potential risk factor for developing type 2 diabetes mellitus (T2DM), with a highly significant heterogeneity among previous studies. Therefore, we examined the association of RHR and risk of incident T2DM among non-diabetic and prediabetic adults.

METHODS

The study population included 2431 men and 2910 women aged ≥ 20 years without T2DM at baseline (2001-2005). Participants were followed for incident T2DM by about 3-year intervals up to April 2018. The multivariable Cox proportional models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs). The models were adjusted for age, body mass index, waist circumference, educational level, physical activity, smoking, hypertension, family history of diabetes, triglycerides/ high-density lipoprotein cholesterol ratio, and fasting plasma glucose.

RESULTS

During a median follow-up of 12.2 years, 313 men and 375 women developed T2DM. Interestingly, a significant sex-difference was found (all P-values for sex interaction < 0.025). Among men, compared to the first quintile (< 68 bpm: beats per minute), those who had RHR of over 84 bpm were at higher T2DM risk with a HR (95%CI) of 1.69 (1.16-2.47). Furthermore, considering RHR as a continuous variable, an increase of 10 bpm caused 17% significantly higher risk among men with a HR of 1.17 (1.05-1.30). However, among women, there was no significant association between incident T2DM and RHR. Moreover, among prediabetic participants at baseline, the association of RHR and risk of T2DM progression was generally similar to the general population, which means higher RHR increased the risk of T2DM development only among men with a HR of 1.26 (1.09-1.46) for 10 bpm increase.

CONCLUSIONS

Among men, being either non-diabetic or prediabetic at baseline, higher RHR can be associated with incident T2DM; however, women didn't show a significant association. Further studies are needed to determine the added value of RHR as a potential modifiable risk factor in screening and risk prediction of incident T2DM.

Impact of individual and environmental factors on dietary or lifestyle interventions to prevent type 2 diabetes development: a systematic review

BACKGROUND

The variability in the effectiveness of type 2 diabetes (T2D) preventive interventions highlights the potential to identify the factors that determine treatment responses and those that would benefit the most from a given intervention. We conducted a systematic review to synthesize the evidence to support whether sociodemographic, clinical, behavioral, and molecular factors modify the efficacy of dietary or lifestyle interventions to prevent T2D.

METHODS

We searched MEDLINE, Embase, and Cochrane databases for studies reporting on the effect of a lifestyle, dietary pattern, or dietary supplement interventions on the incidence of T2D and reporting the results stratified by any effect modifier. We extracted relevant statistical findings and qualitatively synthesized the evidence for each modifier based on the direction of findings reported in available studies. We used the Diabetes Canada Clinical Practice Scale to assess the certainty of the evidence for a given effect modifier.

RESULTS

The 81 publications that met our criteria for inclusion are from 33 unique trials. The evidence is low to very low to attribute variability in intervention effectiveness to individual characteristics such as age, sex, BMI, race/ethnicity, socioeconomic status, baseline behavioral factors, or genetic predisposition.

CONCLUSIONS

We report evidence, albeit low certainty, that those with poorer health status, particularly those with prediabetes at baseline, tend to benefit more from T2D prevention strategies compared to healthier counterparts. Our synthesis highlights the need for purposefully designed clinical trials to inform whether individual factors influence the success of T2D prevention strategies.

Gender differences in the impact of 3-year status changes of metabolic syndrome and its components on incident type 2 diabetes mellitus: a decade of follow-up in the Tehran Lipid and Glucose Study

Background

The aim of this study was to examine the gender differences in the association between status changes of metabolic syndrome (MetS) and its components, using Joint Interim Statement (JIS) criteria, with the risk of type 2 diabetes mellitus (T2DM) among an urban population.

Methods

The study included 4,463 Iranian adult participants (2,549 women) aged ≥20 years. Based on status changes of MetS and its components during 3 years, subjects were categorized into four groups: MetS-free (reference), MetS-developed, MetS-recovery, and MetS-stable. A similar categorization was applied to MetS components. Multivariable Cox regression models were used for estimating hazard ratios (HRs) and women-to-men ratios of HRs (RHRs).

Results

During a median follow-up of 9.3 years, 625 T2DM events (351 women) occurred. Compared with the reference, the HRs of the MetS-developed, -recovery, and -stable groups among men for incident T2DM were 2.90, 2.60, and 4.92; the corresponding values for women were 2.73, 2.88, and 5.21, respectively (all p-values < 0.01), without significant gender difference in these relationships. In both genders, the fasting plasma glucose (FPG) component, regardless of the change in status, was strongly and significantly associated with incident T2DM with HRs ranging from 2.49 to 9.42; a similar association was also found for high waist circumference (WC)-recovery and -stable groups, with HRs ranging from 1.58 to 2.85 (p-values ≤ 0.05). Regarding gender differences, the development and persistence of high blood pressure (BP) status exposed men to greater T2DM risk than women with women-to-men RHRs of 0.43 (0.26-0.72) and 0.58 (0.39-0.86), respectively. Moreover, stable low levels of high-density lipoprotein cholesterol (HDL-C) and high triglyceride (TG) levels conferred higher T2DM risk in women than in men, with women-to-men RHRs of 1.67 (0.98-2.86) and 1.44 (0.98-2.14), respectively (both p-values = 0.06).

Conclusion

Among Tehranian adults, in both genders, all status changes of MetS, even those recovered from MetS, have a higher risk of T2DM compared to those who never had MetS. Also, all statuses of high FPG, in addition to recovered and stable high WC, were strongly associated with T2DM risk. Specifically, men with stable or developed high BP and women with stable dyslipidemic status were at differentially increased risk of incident T2DM.

Role of sociodemographic, clinical, behavioral, and molecular factors in precision prevention of type 2 diabetes: a systematic review

The variability in the effectiveness of type 2 diabetes (T2D) preventive interventions highlights the potential to identify the factors that determine treatment responses and those that would benefit the most from a given intervention. We conducted a systematic review to synthesize the evidence to support whether sociodemographic, clinical, behavioral, and molecular characteristics modify the efficacy of dietary or lifestyle interventions to prevent T2D. Among the 80 publications that met our criteria for inclusion, the evidence was low to very low to attribute variability in intervention effectiveness to individual characteristics such as age, sex, BMI, race/ethnicity, socioeconomic status, baseline behavioral factors, or genetic predisposition. We found evidence, albeit low certainty, to support conclusions that those with poorer health status, particularly those with prediabetes at baseline, tend to benefit more from T2D prevention strategies compared to healthier counterparts. Our synthesis highlights the need for purposefully designed clinical trials to inform whether individual factors influence the success of T2D prevention strategies.

External validation of the American prediction model for incident type 2 diabetes in the Iranian population

Background

The primary aim of the present study was to validate the REasons for Geographic and Racial Differences in Stroke (REGARDS) model for incident Type 2 diabetes (T2DM) in Iran.

Methods

Present study was a prospective cohort study on 1835 population aged ≥ 45 years from Tehran lipids and glucose study (TLGS).The predictors of REGARDS model based on Bayesian hierarchical techniques included age, sex, race, body mass index, systolic and diastolic blood pressures, triglycerides, high-density lipoprotein cholesterol, and fasting plasma glucose. For external validation, the area under the curve (AUC), sensitivity, specificity, Youden’s index, and positive and negative predictive values (PPV and NPV) were assessed.

Results

During the 10-year follow-up 15.3% experienced T2DM. The model showed acceptable discrimination (AUC (95%CI): 0.79 (0.76–0.82)), and good calibration. Based on the highest Youden’s index the suggested cut-point for the REGARDS probability would be ≥ 13% which yielded a sensitivity of 77.2%, specificity 66.8%, NPV 94.2%, and PPV 29.6%.

Conclusions

Our findings do support that the REGARDS model is a valid tool for incident T2DM in the Iranian population. Moreover, the probability value higher than the 13% cut-off point is stated to be significant for identifying those with incident T2DM.

Prevalence of anemia and its associated factors among patients with type 2 diabetes mellitus in a referral diabetic clinic in the north of Iran

BACKGROUND

PURPOSE: This study intended to investigate the prevalence of anemia and its associated factors among patients with type 2 diabetes mellitus (T2DM) in Gorgan, Iran.

METHODS

This cross-sectional study was conducted on 415 (109 men) patients with T2DM referred to the referral diabetes clinic of Sayad Shirazi Hospital in Gorgan in 2021. Demographic information, anthropometric indices, past medical history,  and some laboratory data on cell counts, serum blood glucose, HbA1c, creatinine, lipid/iron profiles, and urinary albumin were collected. The univariable and multivariable logistic regression analysis was applied to compute odds ratios (ORs) and 95% confidence intervals (CI) for potential associated factors, using SPSS version 21. The multivariable Model was adjusted for obesity, Hb A1c, T2DM duration, using glucose-lowering drugs (GLDs), chronic kidney disease (CKD), albuminuria, hypertriglyceridemia, and hypercholesterolemia.  RESULTS: The prevalence of anemia was 21.5% [95%CI: 17.6-25.7] among our total participants. The corresponding values for men and women were 20.2 (13.1-29.0) and 21.9 (17.4-27.0), respectively.The adjusted model revealed that obesity (OR, 1.94 [95% CI, 1.17-3.23]), T2DM duration for more than five years (OR, 3.12 [1.78-5.47]), albuminuria (OR, 6.37 [3.13-10.91]), chronic kidney disease (OR, 4.30 [ 2.83-7.29]) and hypertriglyceridemia (OR, 1.72 [ 1.21-2.77]) were significantly associated with prevalent anemia among patients with T2DM. Moreover, using insulin separately or in combination with oral GLDs associated positively with the prevalence of anemia with ORs of 2.60 [1.42-6.42] and 1.87 [1.30-4.37] , respectively.

CONCLUSION

Anemia had a high prevalence among patients with T2DM in the north of Iran (about 22%), which is associated with obesity, hypertriglyceridemia, duration of T2DM, and diabetic kidney disease.

Association of triglycerides to high-density lipoprotein cholesterol ratio to identify future prediabetes and type 2 diabetes mellitus: over one-decade follow-up in the Iranian population

BACKGROUND

To determine the association between triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) for identifying subjects at risk of incident prediabetes and type 2 diabetes mellitus (T2DM).

METHODS

In 5064 subjects (men = 2247) aged ≥ 20 years, using Cox proportional hazards regression analyses, the associations of TG/HDL-C with incident prediabetes and T2DM were examined among normoglycemic men and women. Furthermore, the association of this lipid ratio with incident T2DM was also assessed among prediabetic subjects (n = 1414). The multivariable analyses were adjusted for age, body mass index, waist-to-height ratio, wrist circumference, systolic blood pressure, family history of T2DM, education level, history of cardiovascular diseases, and fasting plasma glucose (FPG).

RESULTS

During a median follow-up of 11.2 years, 2140 new cases of prediabetes (men = 1070) and 360 incident T2DM (men = 152) were identified among normoglycemic individuals. In the prediabetic population, 574 new cases of T2DM (men = 252) were developed. Among the whole population, compared to the first quartile (reference), higher quartiles of TG/HDL-C were significantly associated with higher risks of incident prediabetes and T2DM among normoglycemic individuals and incident T2DM in the prediabetic population (all P for trend < 0.001). The corresponding hazard ratios (HRs) and 95% confidence intervals (CIs) for the fourth quartiles were 1.37(1.20-1.58), 1.92(1.34-2.75), and 1.57(1.22-2.01), respectively. The sex-stratified analyses demonstrated similar significant associations in both sexes; however, TG/HDL-C lost its association with incident T2DM among prediabetic men. Among the normoglycemic population, 1 unit increase in TG/HDL-C was significantly associated with incident prediabetes and T2DM [1.02(1.00-1.03) and 1.06(1.03-1.08), respectively]. The corresponding value for incident T2DM in prediabetic individuals was 1.01(1.00-1.03). In a subgroup population having insulin data (n = 2897), the associations between TG/HDL-C and incident prediabetes and T2DM among normoglycemic individuals generally persisted even after replacing FPG with an index of insulin resistance (IR), i.e., homeostasis model assessment of IR (HOMA-IR) in the adjusted model.

CONCLUSIONS

In conclusion, in the normoglycemic population, the increasing value of TG/HDL-C was unfavorably associated with incident prediabetes and T2DM, especially among women. Similarly, TG/HDL-C was associated with incident T2DM in prediabetic individuals. Generally, we found that the correlation between TG/HDL-C and different states of dysglycemia is independent of HOMA-IR.

The impact of long-term exposure to PM10, SO2, O3, NO2, and CO on incident dysglycemia: a population-based cohort study

To examine the associations between long-term exposure to five major air pollutants including SO₂, PM₁₀, O₃, NO₂, and CO_, and incident dysglycemia, impaired fasting glucose (IFG), and diabetes, separately. A total of 4254 (1720 men) normoglycemic individuals aged 20-69 years at baseline were followed from 2001 to 2018 every 3 years. To measure the long-term hazards of air pollutants for incident dysglycemia, the Weibull proportional hazards models for every 10-unit increment adjusted for diabetes risk factors were fitted. The air pollutants were put in the models in the form of averages of 1-, 2-, and 3-year periods. During a median follow-up of 12.2 years, we observed 1780 dysglycemia events. In contrast to NO₂, the increase in SO₂, O₃, and PM₁₀ levels were significantly associated with a higher risk of dysglycemia and IFG in all time spans excluding PM₁₀ at 2 years. The largest hazard ratios for incident dysglycemia and IFG were attributable to PM₁₀ in 3 years (2.20 (95% CI 1.67, 2.89) and 2.08 (1.55, 2.80), respectively). Moreover, exposure to all the pollutants except NO₂ in 1 year (0.89 (0.80, 0.98)) had no significant associations with incident diabetes. There was a signal that younger (< 45 years) and never-smoker individuals were more predispose to dysglycemic effects of air pollution (all P for interactions > 0.03). Our findings suggested that long-term exposure to air pollution increased incident dysglycemia risk, the effect which was mainly attributable to IFG status.

Hyperglycemia screening based on survey data: an international instrument based on WHO STEPs dataset

BACKGROUND

Hyperglycemia is rising globally and its associated complications impose heavy health and economic burden on the countries. Developing effective survey-based screening tools for hyperglycemia using reliable surveillance data, such as the WHO STEPs surveys, would be of great importance in early detection and/or prevention of hyperglycemia, especially in low or middle-income regions.

METHODS

In this study, data from the nationwide 2016 STEPs study in Iran were used to identify socioeconomic, lifestyle, and metabolic factors associated with hyperglycemia. Furthermore, the ability of five commonly used machine learning algorithms (random forest; gradient boosting; support vector machine; logistic regression; artificial neural network) in the prediction of hyperglycemia on STEPs dataset were compared via tenfold cross validation in terms of specificity, sensitivity, and the area under the receiver operating characteristic curve.

RESULTS

A total of 17,705 individuals were included in this study, of those 29.624% (n = 5245) had (undiagnosed) hyperglycemia. Multivariate logistic regression analysis showed that older age (for the elderly group: OR = 5.096; for the middle-aged group: OR = 2.784), high BMI status (morbidly obese: OR = 3.465; obese: OR = 1.992), having hypertension (OR = 1.647), consuming fish more than twice per week (OR = 1.496), and abdominal obesity (OR = 1.464) were the five most important risk factors for hyperglycemia. Furthermore, all the five hyperglycemia prediction models achieved AUC around 0.70, and logistic regression (specificity = 70.22%; sensitivity = 70.2%) and random forest (specificity = 70.75%; sensitivity = 69.78%) had the optimal performance.

CONCLUSIONS

This study shows that it is possible to develop survey-based screening tools for early detection of hyperglycemia using data from nationwide surveys, such as WHO STEPs surveys, and machine learning techniques, such as random forest and logistic regression, without using blood tests. Such screening tools can potentially improve hyperglycemia control, especially in low or middle-income countries.

The relationship between glucose intolerance status and risk of hospitalization during two decades of follow-up: Tehran lipid and glucose study

OBJECTIVE

To assess the relationship between glucose intolerance statuses at baseline defined as normal glucose tolerance (NGT), pre-diabetes, newly diagnosed (NDM) and known diabetes mellitus (KDM) and all-cause hospitalization among Iranian men and women during 20 years of follow-up.

RESEARCH DESIGN AND METHODS

This study included 8,014 individuals (3,836 men) ≥30 years from the cohort of Tehran Lipid and Glucose Study. Incidence rate ratios (IRRs) and (95% confidence interval (95% CI) for three groups of pre-diabetes, NDM and KDM was estimated using the Negative Binomial regression model, considering NGT group as reference group. Regression models were adjusted for age, body mass index, hypertension, chronic kidney disease, and cardiovascular disease (CVD).

RESULTS

Among men, compared with NGT group, those with pre-diabetes, NDM and KDM had higher incidence rate for hospitalization, with IRRs (95% CI) of 1.08 (0.96-1.20), 1.38 (1.20-1.57) and 1.96 (1.66-2.26), respectively, after adjusting for confounders. The corresponding values were 1.07 (0.96-1.17), 1.40 (1.21-1.59) and 2.07 (1.72-2.42) for women. Men with diabetes, generally had a higher rate of hospitalization for CVD rather than their female counterparts (IRRs: 1.46; 1.17-1.74). In patients with diabetes, the most common causes of hospitalization were macrovascular complications (i.e. coronary heart disease and stroke). Moreover, among the individuals with diabetes, those with poor glycaemic control (fasting plasma glucose (FPG) >10 mmol/l) had 39% higher rate of hospitalization than those with fair glycaemic control (FPG <10 mmol/l) (1.39; 1.12-1.65), adjusted for confounders.

CONCLUSION

Pre-diabetes, NDM, and KDM were associated with increased hospitalization rates during long-term follow-up. Interventions such as lifestyle modification or pharmacological therapies aiming to slow down the pre-diabetes and fair control of diabetes might potentially decrease the rate of hospitalization.Key messagesNDM and KDM status both increased rate of all-cause hospitalization.CVD and T2DM complication were the most common cause of hospitalization among patients with diabetes.Hospitalization due to recurrent CHD was significantly higher in men with diabetes than their female counterparts.

Identification of the risk factors of type 2 diabetes and its prediction using machine learning techniques

This study identified the risk factors for type 2 diabetes (T2D) and proposed a machine learning (ML) technique for predicting T2D. The risk factors for T2D were identified by multiple logistic regression (MLR) using p-value (p<0.05). Then, five ML-based techniques, including logistic regression, naïve Bayes, J48, multilayer perceptron, and random forest (RF) were employed to predict T2D. This study utilized two publicly available datasets, derived from the National Health and Nutrition Examination Survey, 2009-2010 and 2011-2012. About 4922 respondents with 387 T2D patients were included in 2009-2010 dataset, whereas 4936 respondents with 373 T2D patients were included in 2011-2012. This study identified six risk factors (age, education, marital status, SBP, smoking, and BMI) for 2009-2010 and nine risk factors (age, race, marital status, SBP, DBP, direct cholesterol, physical activity, smoking, and BMI) for 2011-2012. RF-based classifier obtained 95.9% accuracy, 95.7% sensitivity, 95.3% F-measure, and 0.946 area under the curve.

Differences in the impact of impaired glucose status on clinical outcomes in younger and older adults: Over a decade of follow-up in the Tehran lipid and glucose study

Introduction

Studies found that the impact of dysglycemia on microvascular, macrovascular events and mortality outcomes were different between the younger vs. older population. We aimed to investigate the age-specific association of prediabetes with clinical outcomes including type 2 diabetes (T2DM), hypertension, chronic kidney disease (CKD), cardiovascular disease (CVD), and mortality.

Materials and methods

A total of 5,970 Iranians (3,829 women) aged ≥30 years, without T2DM, were included. The age-specific (<60 and ≥60 years; minimum p-value for interaction = 0.001) multivariable-adjusted Cox regression was done to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) of the impaired glucose status including impaired fasting glucose (IFG) vs. normal fasting glucose (NFG), impaired glucose tolerance (IGT) vs. normal glucose tolerance (NGT), and IFG&IGT vs. NFG/NGT with each outcome.

Results

Among individuals aged ≥60 years, the prevalence of impaired glucose status (IFG, IGT, or both) was about 2 times higher compared to those aged <60. Age-specific association between prediabetes and incident hypertension was found for those aged <60 years; [HR (95% CI); IFG: 1.38 (1.16–1.65), IGT: 1.51 (1.26–1.81), and IFG&IGT: 1.62 (1.21–2.12)]. For CVD, in all impaired glycemic states, those aged <60 were at higher significant risk [IFG: 1.39 (1.09–1.77), IGT: 1.53 (1.19–1.97), and IFG&IGT: 1.60 (1.14–2.25)]. Stratified analyses showed similar associations for IFG and IGT with non-CV mortality 1.71 (1.04–2.80) and 2.12 (1.30–3.46), respectively, and for all-cause mortality among those aged <60 years [IFG: 1.63 (1.08–2.45) and IGT: 1.82 (1.20–2.76)]. In both age groups, all glycemic status groups were significantly associated with T2DM but not with CKD and CV mortality.

Conclusions

The high prevalence of prediabetes particularly among the elderly population, limited resources, and the observed significant age differences in the impact of prediabetes states on different clinical outcomes calls for multicomponent intervention strategies by policy health makers, including lifestyle and possible pharmacological therapy, with the priority for the young Iranian population.

Effect of family history of diabetes and obesity status on lifetime risk of type 2 diabetes in the Iranian population

Background

Data are scarce for the lifetime risk of diabetes in the Middle East and North Africa region countries. We estimated the lifetime risk of type 2 diabetes among Iranian adults at age 20 and 40 years, and their variation by family history of diabetes and body mass index (BMI).

Methods

The data from 8435 diabetes-free participants from the Tehran Lipid and Glucose study were used in this analysis. We estimated the lifetime risk of diabetes stratified by sex, and quantified the impact of family history of diabetes and BMI status on the lifetime risks, singly and jointly.

Results

At age 20 years, the overall lifetime risk of diabetes was 57.8% (95% CI = 54.0%-61.8%) for men and 61.3% (57.2%-65.4%) for women. Having both family history of diabetes and increased level of BMI, alone, increased the lifetime risk of diabetes in both sexes. Moreover, the simultaneous presence of family history of diabetes and overweigh/obesity increased the lifetime risk of diabetes in both sexes. So that, at age 20 years the lifetime risk in obese men with positive family history of diabetes was about 54% higher, compared to normal weight men without family history of diabetes; the corresponding value for women was 42%. Also, normal weight men without family history of diabetes lived 24 years longer free of diabetes, compared with obese men with family history of diabetes. In women, the corresponding value was 20 years.

Conclusions

Our study shows the alarming lifetime risk of diabetes across the strata of BMI, which emphasizes the need for more effective interventions to reduce incidence, particularly, among individuals with a positive family history of diabetes.

The Association of Ideal Cardiovascular Health Metrics and Incident Type 2 Diabetes Mellitus Among an urban population of Iran: a decade follow-up in Tehran Lipid and Glucose Study

AIMS

To evaluate the association between ideal cardiovascular health metrics (ICVHM) and incident type diabetes (T2DM) among Iranian men and women.

METHODS

The study population included 7,488 Iranian adults aged ≥20 years (4236 women) free from diabetes at baseline. The ICVHM was defined according to the 2020-American Heart Association. The multivariable Cox proportional hazards regression analysis was used to calculate the hazard ratios (HRs) for ICVHM both as continuous and categorical variables.

RESULTS

Over the median of 9.1 years of follow-up, we identified 922 new cases of T2DM (526 women). Body mass index <30 kg/m² , untreated systolic/diastolic blood pressure <120/80 mmHg in both genders, and physical activity ≥1500 MET mins/wk (only among men) were significantly associated with a lower risk of T2DM. Each additional unit in the ICVHM was associated with a 21% and 15% lower risk of T2DM in men and women, respectively (p-values<0.05). Compared with participants having poor cardiovascular health (CVH), the HR (95% confidence interval) for T2DM risk was 0.69 (0.56-0.85) and 0.35 (0.21-0.59) for men with intermediate and ideal CVHM, respectively. The corresponding values for women were 0.79 (0.65-0.97) and 0.30 (0.15-0.60), respectively. in a subpopulation with nutritional data (n=2236), ideal and intermediate nutritional status was associated with 83% and 77% lower risk of T2DM only among women (p-values<0.05).

CONCLUSION

We found a strong inverse association between having higher global ICVHM with incident T2DM; the issue is mainly attributable to normal blood pressure, normal body weight, and intensive physical activity (only for men).

Incidence of diabetes and its predictors in the Greater Beirut Area: a five-year longitudinal study

BACKGROUND

Type 2 Diabetes (T2D) remains a world epidemic. Obtaining accurate estimates of its incidence and their predictors will aid in targeting preventive measures, allocating resources, and strategizing its management. The Middle East North Africa region has high T2D prevalence and rates of rise. Few incidence studies exist for the region, and none from Lebanon. The current study objective was to determine diabetes incidence and diabetes predictors in a community-based Lebanese sample. A secondary objective was to describe the metabolic control over time in adults with preexisting diabetes.

METHODS

This is a five-year (2014-2019) follow-up study on a random sample of 501 residents of the Greater Beirut area. Out of 478 people eligible to participate in the follow-up study, 198 returned (response rate 39.5%). Assessment included medical history, anthropometric measures, food frequency, sleep, and lifestyle questionnaires. Laboratory data included glycemic indices (fasting glucose and HbA1C) and other biological markers. The diagnosis of probable diabetes (PD) was based on one abnormal test for either fasting glucose ≥ 126 mg/dL or HbA1C ≥ 6.5% or having history of diabetes.

RESULTS

The incidence of diabetes was 17.2 (95% CI 9.6-28.7) per 1000 person-years. Cardiometabolic risk factors independently associated with diabetes were: older age, higher BMI, family history of diabetes, metabolic syndrome, higher CRP and triglyceride level; whereas an independent predictor of diabetes was previous BMI. In addition, the 42 participants with preexisting diabetes had worsening of their metabolic profile over a five-year period.

CONCLUSIONS

The incidence of diabetes was high as compared to some reported world rates, and in line with the high prevalence in the MENA region. The risk was highest in those with positive family history and the presence of the metabolic syndrome or its components. Preventive measures should particularly target participants with that specific risk profile. This becomes particularly important when observing that metabolic control gets worse over time in individuals with diabetes.

The trend of 10-year cardiovascular risk among diabetic and non-diabetic participants in Tehran Lipid and glucose study: 1999-2018

BACKGROUND

Assessing the risk of cardiovascular disease (CVD) is crucial in preventive cardiology. We aimed to determine the trend of CVD risk among individuals with and without diabetes during two decades of follow-up in a Middle Eastern cohort.

METHODS

We studied 8,450 individuals (55.5% women) aged 40-75 years who participated in the Tehran Lipid and Glucose Study (TLGS). Diabetes status and CVD risk factors were evaluated in six examinations from 1999 to 2018. The individual 10-year CVD risk score was calculated using the ACC/AHA recommended risk equation. We used generalized estimating equation models (GEE) to assess the time trends of CVD risk factors and CVD risk scores in diabetic and non-diabetic groups separately.

RESULTS

The age-adjusted ACC/AHA risk score significantly decreased in non-diabetic women and men (from 3.2% to 1.6% in women and 6.8% to 5.0% in men; p for trend < 0.001). Whereas the risk significantly decreased among diabetics men (from 13.8% to 11.5%), it increased somehow among diabetics women (from 5.3% to 5.5%). Furthermore, in both sexes, diabetic individuals compared to non-diabetic ones had better control on their systolic blood pressure, total cholesterol, and fasting plasma glucose during the last two decades.

CONCLUSIONS

The CVD risk and most CVD risk factors improved in individuals with and without diabetes in the past two decades; however, they have not reached the targets yet. So, more stringent lifestyle modifications and treatment strategies are needed, especially for primary prevention in the general population.

Metabolic risk factors among prediabetic individuals and the trajectory toward the diabetes incidence

BACKGROUND

This study investigates the trajectory of the risk factors of prediabetes progression to overt diabetes.

METHODS

The study retrospectively investigated 1610 prediabetic individuals. The trajectory of metabolic indicators was investigated using the generalized estimated equation method with autoregressive working correlation structure through a linear model with the identity link function.

RESULTS

During 15 years of follow-up, the trajectories of metabolic risk factors changed from 3 years before diabetes occurrence for fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG), 6 years for waist circumference (WC), 9 years for high-density lipoprotein cholesterol (HDL-C), and earlier for body mass index, triglyceride (TG), and TG:HDL ratio. It was shown that the differences in the trajectory of WC and HDL were stable after adjustment for other metabolic risk factors. The trajectories of FPG and 2hPG remained stable after considering multiple insulin resistance markers.

CONCLUSIONS

Deterioration of metabolic risk factor status can be a predictor of diabetes many years before its occurrence, but the abrupt change in plasma glucose is evident 3 years before diabetes mellitus onset. It seems that the HDL-C and WC trajectories are two independent predictors for diabetes incidence. It was also found that when the rising trend in plasma glucose starts, preventive strategies to lessen insulin resistance might not be efficient.

The association of parity/live birth number with incident type 2 diabetes among women: over 15 years of follow-up in The Tehran Lipid and Glucose Study

Background

Childbearing may increase the future risk of developing type 2 diabetes mellitus (T2DM) in mothers. However, the issue is not clear completely and not investigated in the Middle East, a region with a high burden of T2DM. In the current study, we examined the association of parity/live birth number with incident T2DM among Iranian women.

Methods

The study population included 2552 women aged 30–65 years recruited in 1999–2001 and were followed for incident T2DM by 3-year intervals. Multivariable Cox proportional hazard models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the parity/live birth number for incident T2DM. Parity number was defined as the number of live childbirth (number of live birth) plus the number of stillbirth (defined as birth of an infant that died after the 20th week of pregnancy in the uterus).

Results

During a median follow-up of 15.4 years, 557 incident T2DM cases have occurred. After adjustment for potential T2DM risk factors and reproductive factors, each additional parity caused a 9% higher risk for incident T2DM. Moreover, compared to women with one parity, those with 3 and ≥ 4 parity had HRs of 1.73 [95% CI: 1.06–2.83] and 2.23 [1.36–3.65], respectively. After further adjustment for body mass index (BMI) and waist circumference, although the HRs were attenuated prominently, parity ≥ 4 was associated with significantly higher risk (HR: 1.72 [1.05–2.83]); even after further adjustment for triglycerides (TG)/ high-density lipoprotein cholesterol (HDL-C), the risk remained marginally significant (HR: 1.64 [1.00–2.70; P value: 0.051]). For the number of live birth, the results were also similar. Moreover, in a sensitivity analysis, when we considered BMI change during follow-up as another covariate, generally, the effect sizes did not change; the trend of HRs across categories of parity number remained marginally significant (P value: 0.064).

Conclusions

During a long-term follow-up, after adjustment for potential T2DM risk factors, reproductive factors, obesity indices, and TG/HDL-C (insulin resistance surrogate), we demonstrated that higher parity/live birth numbers could be associated with increased risk of T2DM development among Iranian women. Moreover, even after further adjustment for BMI change, the suggestive higher risk was still found.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-021-01519-7.

Incidence and risk factors of severe non-proliferative/proliferative diabetic retinopathy: More than a decade follow up in the Tehran Lipids and Glucose Study

Aims/Introduction

To examine the incidence rate of severe non‐proliferative and proliferative diabetic retinopathy (severe‐NPDR/PDR) and determine its potential risk factors.

Materials and Methods

The study consisted of 1,169 participants (675 women) with type 2 diabetes mellitus, aged ≥20 years. A trained interviewer collected information about the history of pan‐retinal photocoagulation as a result of diabetic retinopathy. Multivariable Cox proportional hazards regression models were applied.

Results

We found 187 cases (126 women) of severe‐NPDR/PDR during a median follow‐up period of 12.7 years; the corresponding incidence rate was 13.6 per 1,000 person‐years. Being overweight (hazard ratio [HR], 95% confidence interval [CI] 0.60, 0.39–0.92) and obese (HR 0.48, 95% CI 0.27–0.83) were associated with lower risk, whereas being smoker (HR 1.75, 95% CI 1.12–2.74), having fasting plasma glucose levels 7.22–10.0 mmol/L (HR 2.81, 95% CI 1.70–4.62), fasting plasma glucose ≥10 mmol/L (HR 5.87, 95% CI 3.67–9.41), taking glucose‐lowering medications (HR 2.58, 95% CI 1.87–3.56), prehypertension status (HR 1.65, 95% CI 1.05–2.58) and newly diagnosed hypertension (HR 1.96, 95% CI 1.06–3.65) increased the risk of severe‐NPDR/PDR. Among newly diagnosed diabetes patients, being male was associated with a 59% lower risk of severe‐NPDR/PDR (HR 0.41, 95% CI 0.21–0.79). Furthermore, patients who had an intermediate level of education (6–12 years) had a higher risk of developing PDR (HR 1.86, 95% CI 1.05–3.30) compared with those who had <6 years of education.

Conclusions

Among Iranians with type 2 diabetes mellitus, 1.36% developed severe‐NPDR/PDR annually. Normal bodyweight, being a smoker, out of target fasting plasma glucose level, prehypertension and newly diagnosed hypertension status were independent risk factors of severe‐NPDR/PDR. Regarding the sight‐threatening entity of advanced diabetic retinopathy, the multicomponent strategy to control diabetes, abstinence of smoking and tight control of blood pressure should be considered.

Weight change and risk of cardiovascular disease among adults with type 2 diabetes: more than 14 years of follow-up in the Tehran Lipid and Glucose Study

BACKGROUND

To examine the impact of weight change on incident cardiovascular disease and coronary heart disease (CVD/CHD) among an Iranian population with type 2 diabetes mellitus (T2DM).

METHODS

The study population included 763 participants with T2DM aged ≥ 30 years without a history of CVD and cancer at baseline. Two weight measurements done at baseline and about 3 years later. Based on their weight change, they categorized into: > 5% loss, 3-5% loss, stable (± < 3%), 3-5% gain, > 5% gain. Participants were then followed for incident CVD/CHD annually up to 20 March 2018. Multivariable Cox proportional hazard models, adjusted for age, sex, body mass index, educational level, current smoking, glucose-lowering drug use, family history of CVD, hypertension, hypercholesterolemia, chronic kidney disease, and fasting plasma glucose (FPG) were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of weight change categories for incident CVD/CHD, considering stable weight as reference.

RESULTS

After the weight change measurement, during a median follow-up of 14.4 years, 258 CVD and 214 CHD occurred. Over 5% weight gain was associated with reduced risks of CVD and CHD development by the HRs of 0.70 [95% CI 0.48-1.01; P-value: 0.058] and 0.61 [0.40-0.93], respectively, in multivariable analysis. After further adjustment for FPG change, the HRs of weight gain > 5% were attenuated to 0.75 [0.51-1.10; P-value: 0.138] and 0.66 [043-1.01; P-value: 0.053] for incident CVD and CHD, respectively. The effect of weight loss > 5% was in opposite direction among those older versus younger than 60 years; with suggestive increased risk (not statistically significant) of incident CHD/CVD for the older group. Moreover, weight gain > 5% significantly reduced the risk of CHD only among those older than 60 years (P-value for interaction < 0.2). Furthermore, weight gain > 5% had an association with lower risk of CVD and CHD among sulfonylurea users (0.56 [0.32-0.98] for CVD and 0.54 [0.29-0.99] for CHD).

CONCLUSIONS

Our results with a long-term follow-up showed that weight gain > 5% was associated with better CVD/CHD outcomes among Iranian participants with T2DM, especially older ones. Moreover, we did not find an unfavorable impact on incident CVD/CHD for sulfonylurea-induced weight gain.

Prediction Models for Type 2 Diabetes Risk in the General Population: A Systematic Review of Observational Studies

OBJECTIVES

This study aimed to provide an overview of prediction models of undiagnosed type 2 diabetes mellitus (U-T2DM) or the incident T2DM (I-T2DM) using the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) checklist and the prediction model risk of the bias assessment tool (PROBAST).

DATA SOURCES

Both PUBMED and EMBASE databases were searched to guarantee adequate and efficient coverage.

STUDY SELECTION

Articles published between December 2011 and October 2019 were considered.

DATA EXTRACTION

For each article, information on model development requirements, discrimination measures, calibration, overall performance, clinical usefulness, overfitting, and risk of bias (ROB) was reported.

RESULTS

The median (interquartile range; IQR) number of the 46 study populations for model development was 5711 (1971 - 27426) and 2457 (2060 - 6995) individuals for I-T2DM and U-T2DM, respectively. The most common reported predictors were age and body mass index, and only the Qrisk-2017 study included social factors (e.g., Townsend score). Univariable analysis was reported in 46% of the studies, and the variable selection procedure was not clear in 17.4% of them. Moreover, internal and external validation was reported in 43% the studies, while over 63% of them reported calibration. The median (IQR) of AUC for I-T2DM models was 0.78 (0.74 - 0.82); the corresponding value for studies derived before October 2011 was 0.80 (0.77 - 0.83). The highest discrimination index was reported for Qrisk-2017 with C-statistics of 0.89 for women and 0.87 for men. Low ROB for I-T2DM and U-T2DM was assessed at 18% and 41%, respectively.

CONCLUSIONS

Among prediction models, an intermediate to poor quality was reassessed in several aspects of model development and validation. Generally, despite its new risk factors or new methodological aspects, the newly developed model did not increase our capability in screening/predicting T2DM, mainly in the analysis part. It was due to the lack of external validation of the prediction models.

Long term prognostic implication of newly detected abnormal glucose tolerance among patients with stable cardiovascular disease: a population-based cohort study

Background

Fasting plasma glucose (FPG) and 2-h post challenge plasma glucose (2 h-PCPG), whether as continuous or categorical variables, are associated with incident cardiovascular disease (CVD) and diabetes; however, their role among patients with existing CVD is a matter of debate. We aimed to evaluate associations of different glucose intolerance states with recurrent CVD and incident diabetes among subjects with previous CVD.

Methods

From a prospective population-based cohort, 408 Iranians aged  ≥  30 years, with history of CVD and without known diabetes were included. Associations of impaired fasting glucose (IFG) according to the American Diabetes Association (ADA) and World Health Organization (WHO) criteria, impaired glucose tolerance (IGT), newly diagnosed diabetes (NDM) with outcomes of interest were determined by multivariable Cox proportional hazard models after adjustment for traditional risk factors. Furthermore, FPG and 2 h-PCPG were entered as continuous variables.

Results

Over a decade of follow-up, 220 CVD events including 89 hard events (death, myocardial infarction and stroke) occurred. Regarding prediabetes, only IFG-ADA was associated with increased risk of hard CVD [hazard ratio(HR), 95%CI: 1.62,1.03–2.57] in the age-sex adjusted model. In patients with NDM, those with FPG ≥ 7 mmol/L were at higher risk of incident CVD/coronary heart disease(CHD) and their related hard outcomes (HR ranged from 1.89 to 2.84, all P < 0.05). Moreover, those with 2 h-PCPG ≥ 11.1 mmol/L had significant higher risk of CVD (1.46,1.02–2.11), CHD (1.46,1.00–2.15) and hard CHD (1.95:0.99–3.85, P = 0.05). In the fully adjusted model, each 1 SD increase in FPG was associated with 20, 27, 15 and 25% higher risk of CVD, hard CVD, CHD and hard CHD, respectively; moreover each 1 SD higher 2 h-PCPG was associated with 21% and 16% higher risk of CVD, and CHD, respectively. Among individuals free of diabetes at baseline (n = 361), IFG-ADA, IFG-WHO and IGT were significantly associated with incident diabetes (all P < 0.05); significant associations were also found for FPG and 2 h-PCPG as continuous variables (all HRs for 1-SD increase > 2, P < 0.05).

Conclusions

Among subjects with stable CVD, NDM whether as high FPG or 2 h-PCPG, but not pre-diabetes status was significantly associated with CVD/CHD and related hard outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02950-y.

Prevalence and determinants of diabetes and prediabetes in southwestern Iran: the Khuzestan comprehensive health study (KCHS)

BACKGROUND

The Middle East and North Africa (MENA) is postulated to have the highest increase in the prevalence of diabetes by 2030; however, studies on the epidemiology of diabetes are rather limited across the region, including in Iran.

METHODS

This study was conducted between 2016 and 2018 among Iranian adults aged 20 to 65 years residing in Khuzestan province, southwestern Iran. Diabetes was defined as the fasting blood glucose (FBG) level of 126 mg/dl or higher, and/or taking antidiabetic medications, and/or self-declared diabetes. Prediabetes was defined as FBG 100 to 125 mg/dl. Multinomial logistic regression models were used to examine the association of multiple risk factors that attained significance on the outcome.

RESULTS

Overall, 30,498 participants were recruited; the mean (±SD) age was 41.6 (±11.9) years. The prevalence of prediabetes and diabetes were 30.8 and 15.3%, respectively. We found a similar prevalence of diabetes in both sexes, although it was higher among illiterates, urban residents, married people, and smokers. Participants aged 50-65 and those with Body Mass Index (BMI) 30 kg/m² or higher were more likely to be affected by diabetes [RR: 20.5 (18.1,23.3) and 3.2 (3.0,3.6)]. Hypertension [RR: 5.1 (4.7,5.5)], waist circumference (WC) equal or more than 90 cm [RR: 3.6 (3.3,3.9)], and family history [RR: 2.3 (2.2,2.5)] were also significantly associated with diabetes. For prediabetes, the main risk factors were age 50 to 65 years [RR: 2.6 (2.4,2.8)], BMI 30 kg/m² or higher [RR: 1.9 (1.8,2.0)], hypertension and WC of 90 cm or higher [RR: 1.7 (1.6,1.8)]. The adjusted relative risks for all variables were higher in females than males, with the exception of family history for both conditions and waist circumference for prediabetes.

CONCLUSIONS

Prediabetes and diabetes are prevalent in southwestern Iran. The major determinants are older age, obesity, and the presence of hypertension. Further interventions are required to escalate diabetes prevention and diagnosis in high-risk areas across Iran.

Epidemiology and risk factors for diabetes in the suburbs of Beijing: a retrospective cohort study

OBJECTIVE

We aimed to detect the incidence and risk factors of type 2 diabetes mellitus (T2DM) development in the suburbs of Beijing.

DESIGN

Cohort study with record linkage to incidence data.

SETTING

We performed a 5-year follow-up study in a randomly selected suburban population including 1114 subjects aged ≥18 years living in the suburbs of Beijing.

PARTICIPANTS

118 subjects with T2DM at baseline according to the 1999 WHO criteria were excluded, and 895 subjects attended the follow-up assessment in 2012. The non-diabetic subjects at baseline were classified into two groups: normal glucose tolerance (NGT) group (n=673) and impaired glucose regulation (IGR) group(n=222).The incidence and risk factors of diabetes development in each group were investigated.

OUTCOME MEASURES

A structured questionnaire about sociodemographic characteristics, height, weight, waist circumference, hip circumference, blood pressure, oral glucose tolerance test and serum lipid levels.

RESULTS

Out of the 895 non-diabetic subjects, 67 developed diabetes with 29 in the NGT group and 38 in the IGR group, respectively, after a 5-year follow-up, producing an overall 5-year cumulative incidence of diabetes of 13%. The incidence of diabetes was 15.5 cases per 1000 person-years, 8.9 cases per 1000 person-years in the NGT group and 35.7 cases per 1000 person-years in the IGR group (p<0.01; RR 4.03; 95% CI 2.58 to 9.29). Binary logistic regression analysis showed that the risk factors for diabetes development included fasting plasma glucose (FPG) in the NGT group, and sex, the waist-to-hip ratio, FPG and diastolic blood pressure (DBP) in the IGR group.

CONCLUSIONS

During a mean follow-up of 5.0 years, the incidence of T2DM in the suburbs of Beijing was 15.5 per 1000 person-years. Early prevention of diabetes should focus on IGR subjects. Elevated FPG predicted diabetes development for both NGT and IGR subjects. Female sex, overweight/obesity and DBP are risk factors for diabetes development in IGR subjects.

Trends in cardiovascular risk factors in diabetic patients in comparison to general population in Iran: findings from National Surveys 2007-2016

To determine levels of change in risk factors for cardiovascular disease among people with and without a previous diagnosis of diabetes from 2007 to 2016 in Iran. Data were obtained from five rounds of the World Health Organization STEPwise approach to Surveillance (STEPS) cross-sectional surveys. Participants were 7665 and 93,733 adults with and without known diabetes, respectively, aged 25–65 years. We used logistic and linear regressions to assess the trends of risk factors. Individuals with known diabetes compared to those without the condition, experienced greater reductions in mean levels of systolic blood pressure (3.0 vs. 0.5 mmHg among women and 3.9 vs. 1.6 mmHg among men), diastolic blood pressure (6.4 vs. 5.11 mmHg in women and 3.3 vs. 1.8 mmHg in men), and non-HDL cholesterol (42.4 vs. 27.2 mg/dL among women and 30.3 vs. 21.0 mg/dL among men) throughout these years. Men with diabetes also showed a greater reduction in the prevalence of daily cigarette smoking compared to their non-diabetic counterparts (7.3% vs. 2.3%). Fasting plasma glucose decreased among subjects with diabetes but increased among those without diabetes. Significant increases were observed in proportions who met goals for blood pressure, triglycerides, non-HDL cholesterol and LDL cholesterol in both groups; however, almost half of diabetic subjects did not achieve risk factor goals in 2016. Secondary prevention in diabetic patients was more effective than primary prevention in the general population; however, the rate of diabetic patients who met the designated goals for each risk factor was still suboptimal.

The relationship between spiritual well-being and hope, and adherence to treatment regimen in patients with diabetes

Background

Adherence to treatment regimen is one of the behaviors related to diabetes, which has predicted successful control of the disease and reduced its intensity as well as negative consequences. This study aimed to determine the relationship between spiritual well-being and hope, and adherence to treatment regimen in patients with type II diabetes referred to diabetes clinics.

Methods

In this descriptive-correlational study, 227 diabetic patients referred to healthcare centers and diabetes clinics affiliated to Shiraz University of Medical Sciences were selected via cluster sampling (clinics) followed by convenience sampling (patients). The study data were collected using a demographic information form, spiritual well-being scale developed by Ellison and Paloutzian, Herth hope scale, and adherence to treatment regimen questionnaire. Then, the data were entered into the statistical software and were analyzed using descriptive and inferential statistics.

Results

The results indicated that most participants had moderate spiritual well-being, high hope, and low adherence to treatment regimen. Additionally, spiritual well-being was directly associated with hope and reversely related to adherence to treatment. A significant reverse correlation was also observed between hope and adherence to treatment.

Conclusion

Considering the fact that spiritual well-being and hope were reversely associated with adherence to treatment regimen, further studies should be done in this field. Also patients' image of God and their interpretations of being sick might not be appropriate and need correction.

External validation of the European risk assessment tool for chronic cardio-metabolic disorders in a Middle Eastern population

BACKGROUND

High burden of chronic cardio-metabolic disorders including type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), and cardiovascular disease (CVD) have been reported in the Middle East and North Africa region. We aimed to externally validate a non-laboratory risk assessment tool for the prediction of the chronic cardio-metabolic disorders in the Iranian population.

METHODS

The predictors included age, body mass index, waist circumference, use of antihypertensive medications, current smoking, and family history of cardiovascular disease and/or diabetes. For external validation of the model in the Tehran lipids and glucose study (TLGS), the Area under the curve (AUC) and the Hosmer-Lemeshow (HL) goodness of fit test were performed for discrimination and calibration, respectively.

RESULTS

Among 1310 men and 1960 women aged 28-85 years, 29.5% and 47.4% experienced chronic cardio-metabolic disorders during the 6 and 9-year follow-up, respectively. The model showed acceptable discrimination, with an AUC of 0.72 (95% CI 0.69-0.75) for men and 0.73 (95% CI 0.71-0.76) for women. The calibration of the model was good for both genders (min HL P = 0.5). Considering separate outcomes, AUC was highest for CKD (0.76 (95% CI 0.72-0.79)) and lowest for T2DM (0.65 (95% CI 0.61-0.69)), in men. As for women, AUC was highest for CVD (0.82 (95% CI 0.78-0.86)) and lowest for T2DM (0.69 (95% CI 0.66-0.73)). The 9-year follow-up demonstrated almost similar performances compared to the 6-year follow-up. Using Cox regression in place of logistic multivariable analysis, model's discrimination and calibration were reduced for prediction of chronic cardio-metabolic disorders; the issue which had more effect on the prediction of incident CKD among women. Moreover, adding data of educational levels and marital status did not improve, the discrimination and calibration in the enhanced model.

CONCLUSION

This model showed acceptable discrimination and good calibration for risk prediction of chronic cardio-metabolic disorders in short and long-term follow-up in the Iranian population.

Gender differences in the risk factors for high and very high blood glucose levels: A study of Kerala

BACKGROUND AND AIMS

Worldwide, lifestyle is a significant risk factor for diabetes. Lifestyle changes can lead to differences in the extent of risk of diabetes among women and men. Kerala, a state with one of the best health indicators in India, has a high prevalence of diabetes. This study aimed at comparing the variations in the risk factors for HBG and VHBG among adult women and men in Kerala.

METHODS

Data from the fourth round of the National Family Health Survey (2015-16) used to examine the differences in the risk factors for HBG and VHBG in men and women aged 15-49 years. We used bivariate, multivariate and Population Attributable Risk (PAR) techniques for analysing the data.

RESULTS

Bivariate results have shown the pattern of HBG and VHBG prevalence in women and men was same among all the age groups; however, men show a higher HBG and VHBG than women in all the age groups. Prevalence of HBG and VHBG was higher in women with a primary education, who were poor and not working as compared to their male counterparts. PARs results show that the prevalence of VHBG was higher among obese men and women as compared to normal men and underweight women. Prevalence of HBG was higher among men as compared to women due to alcohol use and weekly consumption of non-vegetarian food.

CONCLUSIONS

The study suggests that there is an urgent need for targeted intervention programs to address the problem of HBG and VHBG in both men and women in Kerala to control blood glucose levels.

Association of wrist circumference with cardio-metabolic risk factors: a systematic review and meta-analysis

BACKGROUND AND AIMS

The association of Wrist Circumference (WrC) with cardio-metabolic risk factors is still contradictory. We aimed to systematically review the association of WrC with cardio-metabolic diseases among the general populations.

METHODS

We systematically searched electronic databases such as PubMed/Medline, Web of Sciences, and Scopus without language restriction until March 2017. Observational studies that examined the association of WrC with any cardio-metabolic risk factors were included. Pooled association of WrC with metabolic syndrome (MetS) was estimated using a random-effect model, and heterogeneity among studies was assessed by I² index and Q test.

RESULTS

A total of 14 papers including cohort study (n = 9), cross-sectional study (n = 4), and case-control study (n = 1) met the criteria and included. The eligible papers have been examined the association of WrC with any cardiovascular disorders (n = 8), metabolic syndrome (n = 4), insulin resistance (IR) (n = 5), diabetes mellitus (n = 2), impaired glucose tolerance (n = 1), cardio-metabolic risk factors (n = 2) and obesity/overweight (n = 1). In the whole population (both adults and pediatric population), high WrC increased the risk of MetS by 33% (Pooled OR = 1.33; 95% CI 1.20, 1.48; I² = 60.2%, p = 0.04), while the pooled OR in adult populations was 1.27 (95% CI 1.15-1.41; I²: 32.8%, p = 0.21). Qualitative synthesis showed that associations of WrC with other cardio-metabolic risk factors are conflicting.

CONCLUSION

High WrC increased the risk of MetS and other cardio-metabolic risk factors. However, due to limited studies, particularly in children, results should be declared with great caution. Further cohort studies are needed to clarify whether WrC is a suitable anthropometric index to predict cardio-metabolic disorders in adult and children populations in different societies.

LEVEL OF EVIDENCE

Level 1, systematic review and meta-analysis.

Obesity is the Most Important Factor for Gender Inequality in Type 2 Diabetes Incidence in an Iranian Population

Background

The results of Shahroud Eye Cohort Study (ShECS) showed a high 5-year incidence of diabetes mellitus with female predominance in 40-64 years old Iranian population. The aim of this report was to decompose the observed sex differences in the incidence of diabetes.

Methods

Sex-specific incidence rate of diabetes was calculated between the two phases of ShECS (2009-2014). The gap decomposition was done by the twofold Blinder-Oaxaca decomposition model.

Results

The results showed that from the total gap (11.19%-15.55% = -4.36%) between the two sexes, 3.46% which forms 79.4% of the total gap is related to the difference in obesity in both genders. In contrast to obesity, age and overweigh status had a decreasing influence on gender inequality.

Conclusions

Obesity of Iranian women compared with men is the most important reason for an increase in the incidence of diabetes in women.

Incidence of type 2 diabetes mellitus and prediabetes in Kerala, India: results from a 10-year prospective cohort

Background

Kerala, the southern state of India, has experienced sudden rise in the prevalence estimates of diabetes. A cohort study on the incidence of type 2 diabetes mellitus (T2DM) in Kerala state thus aptly bridges the lacuna of incidence estimate of T2DM from a population at risk.

Methods

A 10-year prospective cohort study was carried out in two urban wards of central Kerala. The individuals who participated in the baseline survey in 2007 were again invited for a follow-up study in 2017. The data was analyzed using IBM SPSS Statistics for windows (version 21.0). Logistic regression analysis was used to estimate odds ratios and 95% confidence intervals. Findings are based on the 10-year follow-up data from 869 participants from the cohort.

Results

The overall follow-up and response rate of the study was 68.9 and 86.9% respectively. During the follow-up period, 190 people (21.9%) developed T2DM. The incidence rate of T2DM and impaired fasting glucose (IFG) were 24.5 per 1000 person years and 45.01 per 1000 person years respectively. Nearly 60% of participants with baseline IFG were converted to T2DM group in the follow-up period. Age > 45 years, family history of T2DM, BMI ≥ 25 kg/m² and presence of central obesity emerged as important risk factors for incident T2DM.

Conclusion

High incidence of prediabetes over diabetes observed in this study shows an epidemic trend of T2DM in Kerala, India. It requires an immediate public health action.

Circulating nitric oxide metabolites and the risk of cardiometabolic outcomes: a prospective population-based study

Aim: This study was conducted to investigate whether serum NO metabolites (NOx) could predict the occurrence of type 2 diabetes (T2DM), hypertension (HTN) and metabolic syndrome (MetS). Methods: We measured serum NOx concentrations in the Tehran Lipid and Glucose Study participants (aged ≥19 years) and followed them for a median of 7.7 years for the incidence of outcomes. To determine the appropriate cut-off points of serum NOx for predicting clinical events, a random sampling method (50:50 ratio) was used for the population and for analysis, receiver operator characteristic curve was used. Multivariable Cox proportional hazard models were used to estimate the hazard ratios (HRs) with 95% confidence intervals (95% CIs) of T2DM, HTN and MetS in response to serum NOx values. Results: The optimal cut-off points of serum NOx levels for predicting T2DM, HTN and MetS were 26.5, 25.5 and 25.5 µmol/L, respectively. Participants with serum NOx levels ≥25.5 µmol/L had increased risk of MetS (HR = 1.31, 95% CI = 1.01-1.72). No evidence was found for any association of serum NOx with incidence of T2DM and HTN (HR = 1.03, 95% CI = 0.83-1.77 and HR = 1.09, 95% CI = 0.88-1.35). Conclusion: In this prospective population-based investigation, a higher circulating NOx was associated with development of MetS.

Development of type 2 diabetes mellitus in people with intermediate hyperglycaemia

BACKGROUND

Intermediate hyperglycaemia (IH) is characterised by one or more measurements of elevated blood glucose concentrations, such as impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycosylated haemoglobin A1c (HbA1c). These levels are higher than normal but below the diagnostic threshold for type 2 diabetes mellitus (T2DM). The reduced threshold of 5.6 mmol/L (100 mg/dL) fasting plasma glucose (FPG) for defining IFG, introduced by the American Diabetes Association (ADA) in 2003, substantially increased the prevalence of IFG. Likewise, the lowering of the HbA1c threshold from 6.0% to 5.7% by the ADA in 2010 could potentially have significant medical, public health and socioeconomic impacts.

OBJECTIVES

To assess the overall prognosis of people with IH for developing T2DM, regression from IH to normoglycaemia and the difference in T2DM incidence in people with IH versus people with normoglycaemia.

SEARCH METHODS

We searched MEDLINE, Embase, ClincialTrials.gov and the International Clinical Trials Registry Platform (ICTRP) Search Portal up to December 2016 and updated the MEDLINE search in February 2018. We used several complementary search methods in addition to a Boolean search based on analytical text mining.

SELECTION CRITERIA

We included prospective cohort studies investigating the development of T2DM in people with IH. We used standard definitions of IH as described by the ADA or World Health Organization (WHO). We excluded intervention trials and studies on cohorts with additional comorbidities at baseline, studies with missing data on the transition from IH to T2DM, and studies where T2DM incidence was evaluated by documents or self-report only.

DATA COLLECTION AND ANALYSIS

One review author extracted study characteristics, and a second author checked the extracted data. We used a tailored version of the Quality In Prognosis Studies (QUIPS) tool for assessing risk of bias. We pooled incidence and incidence rate ratios (IRR) using a random-effects model to account for between-study heterogeneity. To meta-analyse incidence data, we used a method for pooling proportions. For hazard ratios (HR) and odds ratios (OR) of IH versus normoglycaemia, reported with 95% confidence intervals (CI), we obtained standard errors from these CIs and performed random-effects meta-analyses using the generic inverse-variance method. We used multivariable HRs and the model with the greatest number of covariates. We evaluated the certainty of the evidence with an adapted version of the GRADE framework.

MAIN RESULTS

We included 103 prospective cohort studies. The studies mainly defined IH by IFG5.6 (FPG mmol/L 5.6 to 6.9 mmol/L or 100 mg/dL to 125 mg/dL), IFG6.1 (FPG 6.1 mmol/L to 6.9 mmol/L or 110 mg/dL to 125 mg/dL), IGT (plasma glucose 7.8 mmol/L to 11.1 mmol/L or 140 mg/dL to 199 mg/dL two hours after a 75 g glucose load on the oral glucose tolerance test, combined IFG and IGT (IFG/IGT), and elevated HbA1c (HbA1c5.7: HbA1c 5.7% to 6.4% or 39 mmol/mol to 46 mmol/mol; HbA1c6.0: HbA1c 6.0% to 6.4% or 42 mmol/mol to 46 mmol/mol). The follow-up period ranged from 1 to 24 years. Ninety-three studies evaluated the overall prognosis of people with IH measured by cumulative T2DM incidence, and 52 studies evaluated glycaemic status as a prognostic factor for T2DM by comparing a cohort with IH to a cohort with normoglycaemia. Participants were of Australian, European or North American origin in 41 studies; Latin American in 7; Asian or Middle Eastern in 50; and Islanders or American Indians in 5. Six studies included children and/or adolescents.Cumulative incidence of T2DM associated with IFG5.6, IFG6.1, IGT and the combination of IFG/IGT increased with length of follow-up. Cumulative incidence was highest with IFG/IGT, followed by IGT, IFG6.1 and IFG5.6. Limited data showed a higher T2DM incidence associated with HbA1c6.0 compared to HbA1c5.7. We rated the evidence for overall prognosis as of moderate certainty because of imprecision (wide CIs in most studies). In the 47 studies reporting restitution of normoglycaemia, regression ranged from 33% to 59% within one to five years follow-up, and from 17% to 42% for 6 to 11 years of follow-up (moderate-certainty evidence).Studies evaluating the prognostic effect of IH versus normoglycaemia reported different effect measures (HRs, IRRs and ORs). Overall, the effect measures all indicated an elevated risk of T2DM at 1 to 24 years of follow-up. Taking into account the long-term follow-up of cohort studies, estimation of HRs for time-dependent events like T2DM incidence appeared most reliable. The pooled HR and the number of studies and participants for different IH definitions as compared to normoglycaemia were: IFG5.6: HR 4.32 (95% CI 2.61 to 7.12), 8 studies, 9017 participants; IFG6.1: HR 5.47 (95% CI 3.50 to 8.54), 9 studies, 2818 participants; IGT: HR 3.61 (95% CI 2.31 to 5.64), 5 studies, 4010 participants; IFG and IGT: HR 6.90 (95% CI 4.15 to 11.45), 5 studies, 1038 participants; HbA1c5.7: HR 5.55 (95% CI 2.77 to 11.12), 4 studies, 5223 participants; HbA1c6.0: HR 10.10 (95% CI 3.59 to 28.43), 6 studies, 4532 participants. In subgroup analyses, there was no clear pattern of differences between geographic regions. We downgraded the evidence for the prognostic effect of IH versus normoglycaemia to low-certainty evidence due to study limitations because many studies did not adequately adjust for confounders. Imprecision and inconsistency required further downgrading due to wide 95% CIs and wide 95% prediction intervals (sometimes ranging from negative to positive prognostic factor to outcome associations), respectively.This evidence is up to date as of 26 February 2018.

AUTHORS' CONCLUSIONS

Overall prognosis of people with IH worsened over time. T2DM cumulative incidence generally increased over the course of follow-up but varied with IH definition. Regression from IH to normoglycaemia decreased over time but was observed even after 11 years of follow-up. The risk of developing T2DM when comparing IH with normoglycaemia at baseline varied by IH definition. Taking into consideration the uncertainty of the available evidence, as well as the fluctuating stages of normoglycaemia, IH and T2DM, which may transition from one stage to another in both directions even after years of follow-up, practitioners should be careful about the potential implications of any active intervention for people 'diagnosed' with IH.

Abdominal obesity phenotypes and incident diabetes over 12 years of follow-up: The Tehran Lipid and glucose study

AIMS

To investigate future diabetes in different abdominal obesity phenotypes during 12 years of follow-up.

METHODS

For this population-based cohort, 7982 adults without diabetes including 3533 men and 4449 women, aged ≥20 years were selected from the Tehran Lipid and Glucose Study. Abdominal obesity was defined according to the national cutoffs for waist circumference (WC). Metabolic health was defined as having ≤1 metabolic abnormality based on Joint Interim Statement (JIS) criteria other than WC. Participants were classified into 4 groups of abdominal obesity phenotypes: Metabolically healthy non-abdominal obese (MHNAO), metabolically healthy abdominal obese (MHAO), metabolically unhealthy non-abdominal Obese (MUNAO), and metabolically unhealthy abdominal obese (MUAO).

RESULTS

In total, 1018 cases of incident diabetes occurred. Compared to the MHNAO phenotype, based on multivariate Cox regression models, diabetes risk was increased in all unhealthy phenotypes except the MUNAO phenotype in men. Regarding the association of the MHAO phenotype with incident diabetes, borderline statistical significance in men [HR 1.5 (95% CI: 1.0-2.36), p-value: 0.07] and statistical significance in women [HR 1.68 (95% CI: 1.08-2.6)] were detected.

CONCLUSIONS

In addition to unhealthy phenotypes except the MUNAO phenotype in men, the MHAO phenotype is also associated with incident diabetes, highlighting the importance of preventive strategies in this subgroup of abdominally obese subjects.

Blood Pressure and Hypertension: Findings from 20 Years of the Tehran Lipid and Glucose Study (TLGS)

CONTEXT

Hypertension (HTN) is a well-known modifiable risk factor for cardiovascular disease (CVD), chronic kidney disease and mortality. Positive effects of blood pressure (BP) lowering for prevention of CVD and death have been documented in several meta-analyses of randomized controlled trials.

EVIDENCE ACQUISITION

This review focuses on the key findings derived from the Tehran lipid and glucose study (TLGS) papers on different aspects of BP and HTN.

RESULTS

A prevalence of 23% for HTN has been reported in the TLGS population, aged ≥ 20 years. Over a decade long follow-up, the crude incidence rate (95% CI) of new-onset HTN defined as systolic BP (SBP) ≥ 140 mmHg and/or diastolic BP (DBP) ≥ 90 mmHg, and not using antihypertensive medication was 33.63 (32.0 - 35.3) per 1000 person-years. Age, baseline SBP and body mass index were significant risk factors for development of isolated systolic HTN; regarding isolated diastolic HTN, baseline DBP and waist circumference were recognized as important risk factors whereas age, female gender and marriage were shown to be protective factors. SBP decreased significantly in both diabetic and non-diabetic participants; DBP showed a non-significant decrease in diabetic men and a statistically significant decrease in non-diabetic men. Among women, both those with and without diabetes (DM) generally experienced statistically significant decreases in DBP. Cox proportional hazard models showed that neither SBP nor DBP were associated with incident DM in the total population and in either gender, separately. All BP components were associated with CVD and all-cause mortality in the middle-aged population. Contribution of HTN to cerebrovascular events was also documented in the TLGS participants, aged ≥ 50 years.

CONCLUSIONS

Several important findings regarding BP/HTN have been derived from the TLGS. According to data regarding the prevalence and incidence of preHTN and HTN and their contribution to cardiovascular morbidity and mortality in the TLGS population as a representative sample of Tehranian population, it is recommended that interventions be prioritized for lifestyle modifications for the prevention and appropriate management of preHTN/HTN.

Serum Lipids During 20 Years in the Tehran Lipid and Glucose Study: Prevalence, Trends and Impact on Non-Communicable Diseases

CONTEXT

Dyslipidemia, including elevated serum total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and triglycerides (TG), and low high density lipoprotein cholesterol (HDL-C) is a major modifiable risk factor for non-communicable diseases (NCDs). This review summarizes many of the key findings on lipid measures in the Tehran lipid and glucose study (TLGS), a large scale community-based study with an approximately two decade follow-up.

EVIDENCE ACQUISITION

A systematic literature search was conducted using PubMed, Scopus, Web of Science databases, and the library of the Research Institute for Endocrine Sciences, using the following keywords: Lipid measures, lipid ratios, lipid profile, dyslipidemia, and "Tehran lipid and glucose study". Articles were categorized based on fields of prevalence, trends, and impact of lipid profile on incident NCDs and mortality.

RESULTS

Between 1999 - 2001, the prevalence of high risk lipids ranged from 14% (low HDL-C) to 17% (high LDL-C) among adolescents, although among adults the lowest and highest prevalence were observed for low HDL-C (19%) and high TG (28%). Despite favorable trends for lipid parameters among adolescents, adults, and the elderly population, a considerable number of diabetic individuals, failed to achieve the optimum level of serum lipids. During follow-up, consumption of lipid-lowering drugs increased from 1.5 to 9.0% and 3.7 to 11.4% among adult men and women, respectively. The association between different lipid parameters and related ratios for incident type 2 diabetes (T2D), hypertension, metabolic syndrome and cardiovascular diseases differed between genders. Interestingly, each 1-unit increase in TC/HDL-C increased risk of hypertension among women (odds ratio (OR): 1.19, 95% confidence interval (CI): 1.00 - 1.27) and T2D among men (OR: 1.27, 95% CI: 1.06 - 1.51). Moreover, TC, LDL-C, non-HDL-C, Ln-TG, TC/HDL-C, and Ln-TG/HDL were inversely associated with non-cardiovascular mortality.

CONCLUSIONS

Despite high prevalence of high risk lipid profiles among the TLGS population at baseline, favorable trends were observed in levels of all lipid components, which might be attributable to increased consumption of lipid-lowering medications and improvement in the general knowledge of Iranians regarding limited consumption of hydrogenated oil. Considering the impact of lipid profiles on incident NCDs, more attention should be paid to at-risk groups for screening and treatment purposes.

Diabetes Mellitus: Findings from 20 Years of the Tehran Lipid and Glucose Study

CONTEXT

We summarized findings from Tehran lipid and glucose study (TLGS) about different aspects of type 2 diabetes (T2D) over the span of nearly 2 decades.

EVIDENCE ACQUISITION

A review was undertaken to retrieve papers related to all aspects of T2D from the earliest date available up to January 30, 2018.

RESULTS

An annual crude incidence rate of 10 per 1000 person-years of follow-up was found for T2D in adult participants. Overall incidence rate of pre-diabetes/T2D was 36.3 per 1000 person-years or about 1% each year among youth. Diabetes was associated with increased risk of CVD [hazard ratio (HR): 1.86, 95% confidence interval (95% CI): 1.57 - 2.27] and mortality [HR: 2.56; 95% CI: 2.08 - 3.16] in the total population. Compared with non-diabetic men and women, their diabetic counterparts survived 1.4 and 0.7 years shorter, respectively, during 15 years of follow-up. Wrist circumference, hyperinsulinaemia, 25-hydroxy vitamin D and increase in alanin aminotranferase provided incremental prognostic information beyond the traditional risk factors for incident T2D in adults. Using decision tree algorithms, a number of high risk groups were found for incident T2D. A probability of 84% was found for incidence of T2D among a group of men with fasting plasma glucose (FPG) > 5.3 mmol/L and waist to height ratio (WHtR) > 0.56, and women with FPG > 5.2 mmol/L and WHtR > 0.56.

CONCLUSIONS

Original TLGS studies have contributed greatly to clarify important evidence regarding the epidemiology and risk factors for T2D among Iranian population.

Tobacco Smoking: Findings from 20 Years of the Tehran Lipid and Glucose Study

CONTEXT

Smoking is a global public health priority and accurate data of the local population is essential to improve the health policies against its use. Hence, this study aimed to summarize the important findings available on the prevalence of smoking and its association with non-communicable diseases, documented by one of the largest prospective community-based studies of Iran.

EVIDENCE ACQUISITION

All articles derived from the Tehran Lipid and Glucose Study (TLGS) in the last two decades, from the earliest publications until 30 January 2018 were reviewed for their findings on tobacco smoking.

RESULTS

The prevalence of smoking in non-diabetic adults ≥ 20 years increased between baseline (phase I, 1999 - 2001) and follow-up (phase V, 2008 - 2011) from 25.5% to 35.4% among men and from 3.4% to 6.8% among women. In TLGS adolescents (10 - 18 years) water pipe use increased between 2003 and 2005 from 35.5% to 40.9% among boys and from 19.7% to 26.1% among girls. Regarding health hazards, smoking in men was associated with increased risk of combined impaired fasting glucose/impaired glucose tolerance [hazard ratio (HR) 1.69; confidence interval (CI) 95% 1.15 - 2.48] and hypertension (HR 1.26; CI 95% 0.98 - 1.63). Moreover, men, even smoking less than 10 cigarettes per day, were at increased risk for cardiovascular diseases by HR 2.12 (CI 95% 1.14 - 3.95). For women, the risk of chronic kidney disease dramatically increased 5.74-fold (CI 95% 2.71 - 12.15) among smokers. In the whole population, smoking contributed to 7.7% of all-cause mortality with HR 1.75 (CI 95% 1.38 - 2.22). Other health aspects of tobacco smoke, including its impact on metabolic status, thyroid function, female reproductive system and life style have also been reviewed.

CONCLUSION

Considering hazards of smoking, there is the urgency for more effective preventive measures in Iran; emphasizing the need for further local studies on the hazards of smoking with special attention to women and adolescents and the independent hazards of water pipe use.

Outcomes of a Longitudinal Population-based Cohort Study and Pragmatic Community Trial: Findings from 20 Years of the Tehran Lipid and Glucose Study

CONTEXT

The Tehran lipid and glucose study (TLGS) is one of the oldest population-based longitudinal cohort studies, providing knowledge about the incidence and risk factors of some non-communicable diseases (NCDs) in West Asia which hitherto was relatively scarce. We reviewed the methods and results related to the outcome measurements of this study.

EVIDENCE ACQUISITION

We reviewed all the TLGS papers which reported the incidence of NCDs.

RESULTS

The TLGS was initiated in 1999 - 2001 on a population in district no. 13 of Tehran with the same age distribution of the overall Tehran population and with a middle socioeconomic status. Totally, 15005 individuals, aged ≥ 3 years, participated in the first examination; reexaminations were conducted in a triennial manner and 3550 individuals were added in the second examination. All participants were also followed up annually and asked about any medical event leading to hospitalization or death. A part of participants was assigned to an educational program for lifestyle modification. High incidence of cardiovascular disease (CVD), premature CVD, diabetes and hypertension (around 19, 6, 10 and 31 in men and 11, 5, 11 and 29 in women per 1000 person-year, respectively) besides the high incidence of pre-diabetes and pre-hypertension (around 46 and 76 in men and 37 and 49 in women per 1000 person-year, respectively) showed a worrying situation. Fortunately, the results of the community interventions were promising with around 20% reduction in the risk of metabolic syndrome up to six years.

CONCLUSIONS

These precise detections of different outcomes in the TLGS provided valuable evidences for prediction and prevention of NCDs in Iran with some novelties in the middle-income countries in the world. The Tehran thyroid study (TTS) and the Tehran cardiometabolic genetic study (TCGS), conducted in the framework of the TLGS, are among few studies aiming to determine the natural course of thyroid function and to identify patterns of genetic polymorphisms related to cardiometabolic outcomes, respectively.

Fasting plasma glucose is a stronger predictor of diabetes than triglyceride-glucose index, triglycerides/high-density lipoprotein cholesterol, and homeostasis model assessment of insulin resistance: Tehran Lipid and Glucose Study

AIMS

To compare the impact of triglyceride-glucose index (TyG-index), the product of fasting plasma glucose (FPG) and triglycerides (TG) with FPG, 2 h post-challenge plasma glucose (2 h-PCPG), TG/high-density lipoprotein cholesterol (TG/HDL-C), and homeostasis model assessment of insulin resistance (HOMA-IR) indices for prediction of type 2 diabetes (T2D) in Iranian adults during a median follow-up of 12 years.

METHODS

Study population included 4419 (1858 men) subjects with mean age of 40.6 ± 13.2 years. Multivariable Cox proportional hazard models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for each 1-standard deviation increase in each predictor. Areas under the receiver operating characteristics curves (AUC) and 95% CIs were calculated.

RESULTS

During follow-up, 215 men and 288 women developed T2D. The multivariable HRs for FPG, 2 h-PCPG, TyG-index, HOMA-IR, HOMA2-IR, and TG/HDL-C were 2.20, 1.97, 1.71, 1.33, 1.30, and 1.35 in men and 2.13, 2.11, 1.44, 1.37, 1.32, and 1.36 in women (all P < 0.001). Among the total population, the AUC for FPG [0.752 (0.727-0.776)] was similar to 2 h-PCPG but higher than TyG-index [0.697 (0.673-0.720)], TG/HDL-C [0.644 (0.620-0.669)], HOMA-IR [0.684 (0.659-0.710)], and HOMA2-IR [0.656 (0.630-0.682)]. In men, AUC of TyG-index was higher than TG/HDL-C but did not differ with HOMA-IR indices. In women, the AUC of TyG-index was higher than HOMA2-IR and TG/HDL-C, but was similar to that of HOMA-IR.

CONCLUSIONS

FPG is a stronger predictor of T2D than the TyG-index, TG/HDL-C, and HOMA-IR indices. Although TyG-index was better than TG/HDL-C in both genders, it did not rank above HOMA-IR.

Blood pressure components and incident cardiovascular disease and mortality events among Iranian adults with chronic kidney disease during over a decade long follow-up: a prospective cohort study

Background

To explore the association between systolic and diastolic blood pressure (SBP and DBP respectively) and pulse pressure (PP) with cardiovascular disease (CVD) and mortality events among Iranian patients with prevalent CKD.

Methods

Patients [n = 1448, mean age: 60.9 (9.9) years] defined as those with estimated glomerular filtration rate < 60 ml/min/1.73 m², were followed from 31 January 1999 to 20 March 2014. Multivariable Cox proportional hazard models were applied to examine the associations between different components of BP with outcomes.

Results

During a median follow-up of 13.9 years, 305 all-cause mortality and 317 (100 fatal) CVD events (among those free from CVD, n = 1232) occurred. For CVD and CV-mortality, SBP and PP showed a linear relationship, while a U-shaped relationship for DBP was observed with all outcomes. Considering 120 ≤ SBP < 130 as reference, SBP ≥ 140 mmHg was associated with the highest hazard ratio (HR) for CVD [1.68 (1.2–2.34)], all-cause [1.72 (1.19–2.48)], and CV-mortality events [2.21 (1.16–4.22)]. Regarding DBP, compared with 80 ≤ DBP < 85 as reference, the level of ≥ 85 mmHg increased risk of CVD and all-cause mortality events; furthermore, DBP < 80 mmHg was associated with significant HR for CVD events [1.55 (1.08–2.24)], all-cause [1.68 (1.13–2.5)] and CV-mortality events [3.0 (1.17–7.7)]. Considering PP, the highest HR was seen in participants in the 4th quartile for all outcomes of interest; HRs for CVD events [1.92 (1.33–2.78)], all-cause [1.71 (1.11–2.63)] and CV-mortality events [2.22 (1.06–4.64)].

Conclusions

Among patients with CKD, the lowest risk of all-cause and CV-mortality as well as incident CVD was observed in those with SBP < 140, 80 ≤ DBP < 85 and PP < 64 mmHg.

Impact of 3-year changes in lipid parameters and their ratios on incident type 2 diabetes: Tehran lipid and glucose study

BACKGROUND

To examine the impact of changes in all lipid measures including total cholesterol (TC), log-transformed triglycerides (Ln-TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), non-HDL-C, TC/HDL-C and Ln TG/HDL-C, over an approximate 3 year duration, on incident type 2 diabetes (T2DM).

METHODS

A total of 5474 participants, mean age 41.3 years, without prevalent diabetes at baseline or the first follow-up were entered into the study. The association of lipid changes between baseline and the first follow-up i.e., between 1999-2002 and 2002-2005 for those entered in the first phase (n = 4406) and between 2002-2005 and 2005-2008 for participants recruited in the second phase (n = 1068) with incident T2DM over the follow-up period was assessed, using multivariate Cox proportional hazard analysis.

RESULTS

During a median follow-up of 8.9 years after the second lipid measurements, 577 incident cases of T2DM occurred. After adjustment for a wide variety of confounders and body mass index (BMI) change, each 1-SD increase in TC, Ln-TG, HDL-C, LDL-C, non-HDL-C, Ln-TG/HDL-C and TC/HDL-C was associated with 12, 14, 0.86, 12, 16, 15 and 13% risk for T2DM, respectively (all p-values < 0.05). However, after further adjustment for fasting plasma glucose (FPG) change, the risk disappeared for all lipid measures, excluding HDL-C [hazard ratio (HR): 0.84 (0.76-0.93)], Ln-TG/HDL-C [1.14 (1.04-1.25)] and TC/HDL-C [1.12 (1.04-1.21)].

CONCLUSIONS

Three year changes in all lipid parameters, after adjustment for known risk factors of T2DM and BMI changes, were associated with incident T2DM. The independent risk of HDL-C and its ratios remained even after adjustment for FPG changes.

Optimal cut-points of different anthropometric indices and their joint effect in prediction of type 2 diabetes: results of a cohort study

Background

To determine the anthropometric indices that would predict type 2 diabetes (T2D) and delineate their optimal cut-points.

Methods

In a cohort study, 7017 Iranian adults, aged 20–60 years, free of T2D at baseline were investigated. Using Cox proportional hazard models, hazard ratios (HRs) for incident T2D per 1 SD change in body mass index (BMI), waist circumference (WC), waist to height ratio (WHtR), waist to hip ratio (WHR), and hip circumference (HC) were calculated. The area under the receiver operating characteristics (ROC) curves (AUC) was calculated to compare the discriminative power of anthropometric variables for incident T2D. Cut-points of each index were estimated by the maximum value of Youden’s index and fixing the sensitivity at 75%. Using the derived cut-points, joint effects of BMI and other obesity indices on T2D hazard were assessed.

Results

During a median follow-up of 12 years, 354 men, and 490 women developed T2D. In both sexes, 1 SD increase in anthropometric variables showed significant association with incident T2D, except for HC in multivariate adjusted model in men. In both sexes, WHtR had the highest discriminatory power while HC had the lowest. The derived cut-points for BMI, WC, WHtR, WHR, and HC were 25.56 kg/m², 89 cm, 0.52, 0.91, and 96 cm in men and 27.12 kg/m², 87 cm, 0.56, 0.83, and 103 cm in women, respectively. Assessing joint effects of BMI and each of the obesity measures in the prediction of incident T2D showed that among both sexes, combined high values of obesity indices increase the specificity for the price of reduced sensitivity and positive predictive value.

Conclusions

Our derived cut-points differ between both sexes and are different from other ethnicities.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5611-6) contains supplementary material, which is available to authorized users.

12-year trends in cardiovascular risk factors (2002-2005 through 2011-2014) in patients with cardiovascular diseases: Tehran lipid and glucose study

BACKGROUND

To examine the trend of cardiovascular diseases (CVD) risk factors among a Middle Eastern population with prevalent CVD during a median follow up of 12 years.

METHODS

Patients with prevalent CVD (n = 282, men = 167), with a mean age of 60.76 years were evaluated in four study phases of the TLGS (Tehran lipid glucose study), 2002-2005, 2005-2008, 2008-2011, and 2011-2014. Trends of CVD risk factors were estimated using generalized estimation equation (GEE) models, by adjusting for gender, age and propensity scores.

RESULT

The adjusted prevalence of general and central adiposity, diabetes and physical inactivity at baseline was 25.18, 60.14, 25.03 and 43.74%, respectively and had increasing trends during the study period, reaching 41.32, 66.74, 43.20 and 50.32%, respectively, at the last visit. Although systolic, but not diastolic blood pressure, decreased from 134.88 to 129.86 mmHg, the prevalence of hypertension did not decrease (64.21% vs 68%, p value = 0.326). The prevalence of low high density lipoprotein cholesterol (HDL-C), hypertriglyceridemia and high non-HDL-C at baseline was 74.54, 59.89 and 96.53%, respectively, and showed improved trends reaching 44.87, 47.12 and 96.06% respectively; however, the favorable trend was not observed for high low density cholesterol. Significant increasing trends were observed in the consumption of anti-hypertensive, lipid and glucose lowering medications, but not for aspirin. The prevalence of current smoking (11.05 vs 16.83%, p value = 0.042) and chronic kidney disease (44.16 vs 51.65%, p value = 0.054) increased during follow up.

CONCLUSION

Except for lipid profile status, dangerous trends for other CVD risk factors were demonstrated among CVD patients, which can be a harbinger for high rates of CVD mortality; these findings highlight the need for urgent implementation of multicomponent interventions to control CVD risk factors among these patients.