The effect of obesity phenotype changes on cardiovascular outcomes in adults older than 40 years in the prospective cohort of the Tehran lipids and glucose study (TLGS): joint model of longitudinal and time-to-event data

BACKGROUND

Obesity is a worldwide health concern with serious clinical effects, including myocardial infarction (MI), stroke, cardiovascular diseases (CVDs), and all-cause mortality. The present study aimed to assess the association of obesity phenotypes and different CVDs and mortality in males and females by simultaneously considering the longitudinal and survival time data.

METHODS

In the Tehran Lipid and Glucose Study (TLGS), participants older than three years were selected by a multi-stage random cluster sampling method and followed for about 19 years. In the current study, individuals aged over 40 years without a medical history of CVD, stroke, MI, and coronary heart disease were included. Exclusions comprised those undergoing treatment for CVD and those with more than 30% missing information or incomplete data. Joint modeling of longitudinal binary outcome and survival time data was applied to assess the dependency and the association between the changes in obesity phenotypes and time to occurrence of CVD, MI, stroke, and CVD mortality. To account for any potential sex-related confounding effect on the association between the obesity phenotypes and CVD outcomes, sex-specific analysis was carried out. The analysis was performed using packages (JMbayes2) of R software (version 4.2.1).

RESULTS

Overall, 6350 adults above 40 years were included. In the joint modeling of CVD outcome among males, literates and participants with a family history of diabetes were at lower risk of CVD compared to illiterates and those with no family history of diabetes in the Bayesian Cox model. Current smokers were at higher risk of CVD compared to non-smokers. In a logistic mixed effects model, odds of obesity phenotype was higher among participants with low physical activity, family history of diabetes and older age compared to males with high physical activity, no family history of diabetes and younger age. In females, based on the results of the Bayesian Cox model, participants with family history of diabetes, family history of CVD, abnormal obesity phenotype and past smokers had a higher risk of CVD compared to those with no history of diabetes, CVD and nonsmokers. In the obesity varying model, odds of obesity phenotype was higher among females with history of diabetes and older age compared to those with no history of diabetes and who were younger. There was no significant variable associated with MI among males in the Bayesian Cox model. Odds of obesity phenotype was higher in males with low physical activity compared to those with high physical activity in the obesity varying model, whereas current smokers were at lower odds of obesity phenotype than nonsmokers. In females, risk of MI was higher among those with family history of diabetes compared to those with no history of diabetes in the Bayesian Cox model. In the logistic mixed effects model, a direct and significant association was found between age and obesity phenotype. In males, participants with history of diabetes, abnormal obesity phenotype and older age were at higher risk of stroke in the Bayesian Cox model compared to males with no history of diabetes, normal obesity phenotype and younger persons. In the obesity varying model, odds of obesity phenotype was higher in males with low physical activity, family history of diabetes and older age compared to those with high physical activity, no family history of diabetes and who were younger. Smokers had a lower odds of obesity phenotype than nonsmokers. In females, past smokers and those with family history of diabetes were at higher risk of stroke compared to nonsmokers and females with no history of diabetes in the Bayesian Cox model. In the obesity varying model, females with family history of diabetes and older ages had a higher odds of obesity phenotype compared to those with no family history of diabetes and who were younger. Among males, risk of CVD mortality was lower in past smokers compared to nonsmokers in the survival model. A direct and significant association was found between age and CVD mortality. Odds of obesity phenotype was higher in males with a history of diabetes than in those with no family history of diabetes in the logistic mixed effects model.

CONCLUSIONS

It seems that modifications to metabolic disorders may have an impact on the heightened incidence of CVDs. Based on this, males with obesity and any type of metabolic disorder had a higher risk of CVD, stroke and CVD mortality (excluding MI) compared to those with a normal body mass index (BMI) and no metabolic disorders. Females with obesity and any type of metabolic disorder were at higher risk of CVD(, MI and stroke compared to those with a normal BMI and no metabolic disorders suggesting that obesity and metabolic disorders are related. Due to its synergistic effect on high blood pressure, metabolic disorders raise the risk of CVD.

Optimizing cardiovascular disease mortality prediction: a super learner approach in the tehran lipid and glucose study

BACKGROUND & AIM

Cardiovascular disease (CVD) is the most important cause of death in the world and has a potential impact on health care costs, this study aimed to evaluate the performance of machine learning survival models and determine the optimum model for predicting CVD-related mortality.

METHOD

In this study, the research population was all participants in Tehran Lipid and Glucose Study (TLGS) aged over 30 years. We used the Gradient Boosting model (GBM), Support Vector Machine (SVM), Super Learner (SL), and Cox proportional hazard (Cox-PH) models to predict the CVD-related mortality using 26 features. The dataset was randomly divided into training (80%) and testing (20%). To evaluate the performance of the methods, we used the Brier Score (BS), Prediction Error (PE), Concordance Index (C-index), and time-dependent Area Under the Curve (TD-AUC) criteria. Four different clinical models were also performed to improve the performance of the methods.

RESULTS

Out of 9258 participants with a mean age of (SD; range) 43.74 (15.51; 20-91), 56.60% were female. The CVD death proportion was 2.5% (228 participants). The death proportion was significantly higher in men (67.98% M, 32.02% F). Based on predefined selection criteria, the SL method has the best performance in predicting CVD-related mortality (TD-AUC > 93.50%). Among the machine learning (ML) methods, The SVM has the worst performance (TD-AUC = 90.13%). According to the relative effect, age, fasting blood sugar, systolic blood pressure, smoking, taking aspirin, diastolic blood pressure, Type 2 diabetes mellitus, hip circumference, body mss index (BMI), and triglyceride were identified as the most influential variables in predicting CVD-related mortality.

CONCLUSION

According to the results of our study, compared to the Cox-PH model, Machine Learning models showed promising and sometimes better performance in predicting CVD-related mortality. This finding is based on the analysis of a large and diverse urban population from Tehran, Iran.

Higher dietary flavonol and isoflavonoid intakes are associated with lower incidence of type 2 diabetes

Background: Adequate evidence supports beneficial effects of plant-derived phytochemicals against type 2 diabetes (T2D). Among phytochemicals, dietary flavonoids is one of the superb candidates. The whole studies are carried out in Western populations, so it is needed to investigate the risk of T2D by dietary flavonoid intakes in ethnic origins and other regions to confirm these relations. This study was conducted to investigate whether the daily consumption of total flavonoid and its subclasses can affect the incidence of type 2 diabetes (T2D) in the Iranian population. Methods: Eligible adults (n=6547) were selected from among participants of the Tehran lipid and glucose study with an average follow-up of 3.0 years. Dietary intakes were assessed using a valid and reliable 168-item semi-quantitative food frequency questionnaire. Multivariate Cox proportional hazard regression models were used to estimate the development of T2D in relation to total intake of flavonoids. Results: This study was conducted on 2882 men and 3665 women, aged 41.3±14.6 and 39.0±13.4 years, respectively. After adjustment for several potential confounders (age, sex, diabetes risk score, physical activity, energy, fiber and total fat intakes), risk of T2D decreased from tertiles 1 to 3 for flavonols (HR (95% CI): 1.00, 0.86 (0.64-1.16), 0.87 (0.63-0.93), P_trend=0.01) and isoflavonoids (HR (95% CI): 1.00, 0.84 (0.62-1.13), 0.64 (0.46-0.88), P_trend=0.02), whereas non-significant results were found for total flavonoid and other subclasses of flavonoid. Conclusion: These results emphasize the potential protective role of flavonols and isoflavonoids rich food (e.g. apple, tea, soy, and dark chocolate) in the prevention of T2D.

Health-related quality of life in men and women who experienced cardiovascular diseases: Tehran Lipid and Glucose Study

Background

Cardiovascular diseases (CVDs) are among the most common causes of death worldwide, including in Iran. Considering the adverse effects of CVDs on physical and psychosocial health; this study aims to investigate the association between experience of CVDs and health-related quality of life (HRQoL) in adult participants of the Tehran Lipid and Glucose Study (TLGS).

Methods

The participants of this cross-sectional study were 7009 adults (≥ 20 years) who participated in the TLGS during 2014–2017. Demographic information and HRQoL data was collected through validated questionnaires by trained interviewers. HRQoL was assessed by the Iranian version of the SF-12 questionnaire. Data was analyzed using the SPSS software.

Results

The mean age of participants was 46.8 ± 14.6 years and 46.1% of them were men. A total of 9.0% of men and 4.4% of women had CVDs. In men, the mean physical HRQoL summary score was significantly lower in those with CVDs compared to those without CVDs (46.6 ± 0.8 vs. 48.5 ± 0.7, p > 0.001). In women, the mean mental HRQoL summary scores was significantly lower in those with CVDs compared to those without CVDs (42.8 ± 1.0 vs. 45.2 ± 0.5, p = 0.009). In adjusted models, men with CVDs were more likely to report poor physical HRQoL compared to men without CVDs (OR(95%CI): 1.93(1.32–2.84), p = 0.001); whereas for women, the chance of reporting poor mental HRQoL was 68% higher in those with CVDs than those without CVDs (OR(95%CI): 1.68(1.11–2.54), p = 0.015).

Conclusion

The findings of the current study indicate poorer HRQoL in those who experienced CVDs compared to their healthy counterparts with a sex specific pattern. While for men, CVDs were associated with more significant impairment in the physical dimension of HRQoL, women experienced a similar impairment in the mental dimension of HRQoL.

Sex-specific prevalence of coronary heart disease among Tehranian adult population across different glycemic status: Tehran lipid and glucose study, 2008-2011

Background

Coronary heart disease (CHD) is one of the leading causes of death. Alarmingly Iranian populations had a high rank of CHD worldwide. The current study aimed to assess the prevalence of CHD across different glycemic categories.

Methods

This study was conducted on 7718 Tehranian participants (Men = 3427) aged ≥30 years from 2008 to 2011. They were categorized based on glycemic status. The prevalence of CHD was calculated in each group separately. CHD was defined as hospital records adjudicated by an outcome committee. The association of different glycemic categories with CHD was calculated using multivariate logistic regression, compared with normal fasting glucose /normal glucose tolerance (NFG/NGT) group as reference.

Results

The age-standardized prevalence of isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT), both impaired fasting glucose and impaired glucose tolerance (IFG/IGT), newly diagnosed diabetes mellitus (NDM), and known diabetes mellitus (KDM) were 14.30% [95% confidence interval (CI): 13.50–15.09], 4.81% [4.32–5.29], 5.19% [4.71–5.67], 5.79% [5.29–6.28] and 7.72% [7.17–8.27], respectively.

Among a total of 750 individuals diagnosed as cases of CHD (398 in men), 117 (15.6%), 453 (60.4%), and 317 (42.3%) individuals had a history of myocardial infarction (MI), cardiac procedure, and unstable angina, respectively. The age-standardized prevalence of CHD for the Tehranian population was 7.71% [7.18–8.24] in the total population, 8.62 [7.81–9.44] in men and 7.19 [6.46–7.93] in women. Moreover, among diabetic participants, the age-standardized prevalence of CHD was 13.10 [9.83–16.38] in men and 10.67 [8.90–12.44] in women, significantly higher than corresponding values for NFG/NGT and prediabetic groups.

Across six levels of glycemic status, CHD was associated with IFG/IGT [odds ratio (OR) and 95% CI: 1.38 (1.01–1.89)], NDM [1.83 (1.40–2.41)], and KDM [2.83 (2.26–3.55)] groups, in the age- and sex-adjusted model. Furthermore, in the full-adjusted model, only NDM and KDM status remained to be associated with the presence of CHD by ORs of 1.40 (1.06–1.86) for NDM and 1.91 (1.51–2.43) for KDM.

Conclusion

The high prevalence of CHD, especially among diabetic populations, necessitates the urgent implementation of behavioral interventions in the Tehranian population, according to evidence-based guidelines for the clinical management of diabetic patients.

Advanced glycation end products and risk of hypertension in Iranian adults: Tehran lipid and glucose study

Background:

Elevated blood pressure is still one of the major risk factors for diseases and disabilities and also a public health challenge worldwide. In the present longitudinal study, we aimed to evaluate the association between risk of hypertension and dietary advanced glycation end products (AGEs) as a recently discussed potential risk factor.

Materials and Methods:

Dietary assessment of 1775 participants in the third phase of Tehran lipid and glucose study to obtain dietary intake of AGEs was performed using a validated semi-quantitative food frequency questionnaire, and they were followed up for a mean duration of approximately 6 years. To determine the incidence of hypertension across quartiles of AGEs intake, logistic regression models with adjustment for potential confounding variables were used. All statistical analyses were conducted using SPSS, and P < 0.05 was considered statistically significant.

Results:

Higher hypertension occurrence risk was generally attributed to higher AGEs intake quartiles after adjusting for age in men (odds ratio [OR] = 1.48, 95% confidence interval [CI] = 1.11–1.52, P = 0.038) and additional adjustment for smoking, drugs, and physical activity in women (OR = 1.38%–95% CI = 1.09–1.42, P = 0.042). Moreover, across the increasing trend of dietary AGEs intake, the percentage of fat intake increased and that of carbohydrate significantly decreased (P < 0.0001).

Conclusion:

In conclusion, it is highly recommended to limit dietary AGEs consumption to prevent and manage hypertension and its complications.

Prospective Study of Nut Consumption and Incidence of Metabolic Syndrome: Tehran Lipid and Glucose Study

This study aimed to assess the association of various types of nut per se, and total nut consumption with the incidence of metabolic syndrome (MetS). A 6.2 ± 0.7-year population-based prospective study was conducted among 1265 adults, aged 19–74 years, participants of the Tehran Lipid and Glucose Study. A 168-item semi-quantitative food frequency questionnaire was used to collect information on nut consumption. MetS was defined according to the Joint Interim Statement guidelines and 276 new cases of MetS were identified. Median ± interquartile range of nut consumption was 2.08 (0.88–5.68) servings/week. After adjusting for family history of diabetes, age, gender, smoking, physical activity, fasting serum glucose at baseline, serum high density lipoprotein cholesterol (HDL-C) at baseline, energy intake, fiber, macronutrients, cholesterol intake, fruit, vegetables, dairy products and body mass index (BMI), a statistically significant decrease was observed in MetS in the third (≥5 servings/week) tertile of nuts (odds ratio: 0.68, 95% CI: 0.44–0.91, p trend: 0.03) compared with the lowest (≤1 serving/week). Walnut consumption showed a significant, inverse association with MetS risk; associations for other nut varieties were not significant. For each additional serving/week of walnuts consumed, incidence of MetS decreased by 3% (ORs: 0.97 CI: 0.93–0.99), after adjusting for confounding factors. Total nut consumption, especially walnuts, reduces the risk of MetS.

Associations between dairy products consumption and risk of type 2 diabetes: Tehran lipid and glucose study

We aimed to examine the relationship between total dairy and dairy subtypes with the risk of type 2 diabetes (T2DM) in an Asian population. A nested case-control study of 178 cases of incident T2DM and 520 matched controls was conducted within the Tehran lipid and glucose study (TLGS). A 27% lower risk of T2DM was found per 100 g/d total dairy consumption that tend to be significant (95% CI: 0.52-1.02). Milk intake was inversely associated with diabetes after adjustment for confounders (p-trend: 0.042). Milk intake was associated with decreased T2DM risk in men (p-trend: 0.025), but not in women (p-trend: 0.527). Each 100 g/d increase in milk intake corresponded to 41% lower T2DM risk in fully adjusted model (95% CI: 0.39-0.89) in men. In conclusion, there is no significant association between diabetes and total dairy intake in the present study, but high intake of milk may reduce T2DM risk among men.