Effect of weight change on the association between overall and source of carbohydrate intake and risk of metabolic syndrome: Tehran lipid and glucose study.

BACKGROUND: In this prospective cohort study, we aimed to evaluate the association between dietary carbohydrates, whole grains, refined grains, and simple sugar with the risk of metabolic syndrome (MetS) and assess the effect of weight change on these associations. METHODS: This study was conducted within the framework of the Tehran Lipid and Glucose Study (TLGS). We included 1915 healthy participants with complete demographic, anthropometric and dietary measurements, among whom 591 developed MetS during 8.9 years of follow-up. Intake of dietary carbohydrates, whole grains, refined grains, and simple sugar was assessed with a validated semi-quantitative food frequency questionnaire. Multivariable adjusted Cox regression was used to estimate hazard ratios (HRs) for MetS events across tertiles of dietary variables. Using joint classification, the effect of weight change on the association between dietary variables and risk of MetS was assessed by Cox regression. RESULTS: Carbohydrate intake was not associated with the risk of MetS in multivariable-adjusted models. Whole grains intake was inversely associated with the risk of MetS (HR: 0.78, CI: 0.63-0.98), while this association disappeared after adjustment for weight change. The risk of MetS increased by 11% (1.11, 1.09-1.14) for each 3% energy increment from simple sugar, and by 5% (1.05, 1.03-1.08) for each 1 serving/day increment in refined grains. Consumption of refined grains increased the risk of MetS; an effect modification of this association was found by weight change. Among subjects with weight loss, intake of refined grains < median intake decreased the risk of MetS (0.59, 0.41-0.87). However, consumption of refined grains ≥ median intake increased the risk of MetS in individuals with weight gain (1.47, 1.08-2.01). Simple sugar was positively associated with an increased risk of MetS, after adjustment for weight change (3.00, 2.37-3.82). In joint classification, intake of simple sugar greater than median intake increased the risk of MetS, independent of weight change. CONCLUSION: Our findings suggest an effect modification by weight change on the association between carbohydrates, and refined grains intake and the risk of MetS. Weight loss along with lower consumption of carbohydrates, and refined grains reduced the risk of MetS. However, simple sugar intake, regardless of weight change, was associated with an increased risk of MetS.

Dietary fatty acid patterns and risk of metabolic syndrome: Tehran lipid and glucose study.

BACKGROUND: The association between individual dietary fatty acids (FAs) and risk of metabolic syndrome (MetS) has been investigated in previous studies. However, synergistic or additive effects of multiple FA have received less attention. Hence, we aimed to determine the major dietary FA patterns and evaluate the association between FA patterns and risk of MetS. METHODS: Dietary intakes of 1713 MetS-free adults who participated in the third phase of the Tehran Lipid and Glucose Study (TLGS) were assessed using a validated 168-items food frequency questionnaire. FA patterns were obtained by principal component analysis (PCA). Adjusted Hazard Ratios (HRs) and 95% confidence intervals (CIs) were calculated for the association of MetS incident with the extracted FA patterns. RESULTS: Four major FA patterns were identified through PCA of the 24 FAs consumed: "short- and medium-chain saturated fatty acid (SFA) pattern", "long-chain FA pattern", "omega-3 PUFA pattern", and "long-chain SFA pattern". There was no significant association between dietary FA patterns and risk of MetS incidence. CONCLUSIONS: We found no significant association between FA patterns and risk of MetS. More prospective cohort studies and clinical trials are needed to clarify the issue.

Snack consumption patterns and their associations with risk of incident metabolic syndrome: Tehran lipid and glucose study.

AIM: Few studies considered the association between snack patterns and metabolic abnormalities. Here we aimed to characterize the major snack patterns among Iranian adults and determine their association with the risk of metabolic syndrome (MetS). METHODS: This study was conducted on 1713 MetS-free adults who participated in the third phase of the Tehran Lipid and Glucose Study (TLGS). At baseline, dietary intake of snack was assessed using a validated 168-items food frequency questionnaire, and snack patterns were obtained by principal component analysis (PCA). Adjusted Hazard Ratios (HRs) and 95% confidence intervals (CIs) were calculated for the association of incident MetS with the extracted snack patterns. RESULTS: PCA identified five major snack patterns, defined as "healthy pattern", "low-fructose pattern", "high-trans pattern", "high-caffeine pattern" and "high-fructose pattern". Participants in the highest tertile of the "high-caffeine pattern" had lower risk of MetS (HR = 0.80, 95% CI = 0.65-0.99, P for trend = 0.032). Other snack patterns have not shown any significant association with MetS incidence. CONCLUSIONS: Our findings suggest that consuming a snack pattern with high loads of caffeine, defined as "High-caffeine pattern" in the present study, could reduce the risk of MetS in healthy adults. Further prospective studies are needed to more fully determine the association between snack patterns and MetS incidence.

High-Fat Dairy Products May Decrease the Risk of Chronic Kidney Disease Incidence: A Long-Term Prospective Cohort Study.

OBJECTIVE: The association between consumption of dairy products and risk of chronic kidney disease (CKD) is under debate. We aimed to determine the potential effects of total and subtypes of dairy intake on the occurrence of CKD. METHODS: This study was conducted within the Tehran Lipid and Glucose Study (TLGS) on 2416 CKD-free adults. At baseline, consumption of dairy products was estimated using a validated 168-items semiquantitative food frequency questionnaire. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of CKD were calculated in tertile categories of dairy products. Also, the CKD risk was estimated with multivariable Cox regression to substitute total dairy with other dietary protein sources. RESULTS: During 8.4 years of follow-up, the incidence rate of CKD was 21%. The participants' mean (±SD) age was 38 (±13) years and 46% were men. Dietary intakes of total dairy, low-fat dairy, and fermented dairy were not associated with CKD risk. There were significant lower risks of CKD in the highest compared to the lowest tertiles of high-fat dairy (HR = 0.76, 95% CI = 0.60-0.95) and high-fat milk (HR = 0.75, 95% CI = 0.59-0.96). However, no significant associations were found between other categories of dairy products and CKD incidence. Substitutions of total dairy with other dietary protein sources were not associated with CKD risk. CONCLUSIONS: In this study, higher intakes of high-fat dairy and high-fat milk were associated with lower risks of CKD. No significant associations were found between other dairy products and CKD. More prospective and clinical trials are needed to clarify the issue.

Saturated Fatty Acid Intake and Risk of Type 2 Diabetes: An Updated Systematic Review and Dose-Response Meta-Analysis of Cohort Studies.

This systematic review and meta-analysis was conducted to pool findings of cohort studies that investigated hazards of type 2 diabetes mellitus (T2DM) in relation to intakes of SFAs. A systematic search was conducted in the PubMed, Scopus, and Embase databases up to June 2021 to find eligible studies. Review articles or commentaries, clinical trials, cross-sectional studies, studies on gestational or type 1 diabetes patients, animal studies, articles with no access to full-texts, articles published in non-English languages, and articles with missing critical data needed for the systematic review were excluded from the meta-analysis. A random-effects model was used to combine study-specific results. Thirteen cohort studies with 361,686 participants and 11,865 T2DM events were included. Dietary total SFA intake, as well as dietary palmitic acid (PA) or stearic acid (SA) were not associated with risk of T2DM when the highest was compared with the lowest intake category (HR = 0.99; 95% CI: 0.91, 1.09; n = 13 for total SFAs; HR = 0.96; 95% CI: 0.79, 1.15; n = 4 for PA; and HR = 1.08; 95% CI: 0.79, 1.49; n = 4 for SA). However, the risk of T2DM decreased by 11% in the highest compared with the lowest category of dietary lauric acid (HR = 0.89; 95% CI: 0.82, 0.97; n = 2), and by 17% in the highest compared with lowest category of dietary myristic acid (MA) (HR = 0.83; 95% CI: 0.74, 0.92; n = 3). There was evidence of publication bias among studies on dietary total SFAs and T2DM. Our results indicated no significant association between dietary total SFA and risk of T2DM. However, dietary intake of MA was negatively associated with developing T2DM.

Spot urinary microalbumin concentration, metabolic syndrome and type 2 diabetes: Tehran lipid and glucose study.

AIM: This study aimed to determine the association of urinary microalbumin concentrations with type 2 diabetes mellitus (T2DM), metabolic syndrome (MetS), and its phenotypes. The optimum cut-off values of urinary microalbumin and microalbumin-to-creatinine ratio (MCR) for predicting the chance of having T2DM and MetS were also defined. METHODS: Adult men and women (n = 1192) participated in the sixth phase (2014-2017) of the Tehran Lipid and Glucose Study (TLGS), with completed data, were included in the analyses. Odds ratios (ORs) (and 95% confidence intervals (CIs)) of T2DM, MetS, and its components across tertile categories of urinary microalbumin concentrations were estimated using multivariable logistic regressions. The optimal cut-off points of urinary microalbumin and MCR were determined using the receiver operator characteristic (ROC) curve analysis. RESULTS: Participants' mean (±SD) age was 44.9 (±14.0) years, and 44.6% of the participants were men. The prevalence of microalbuminuria was 14.4%. Chance of having T2DM was significantly higher in the highest tertile of urinary microalbumin concentration (OR = 2.29, 95% CI = 1.43-3.67) and MCR (OR = 1.82, 95% CI = 1.15-2.89). Subjects with the highest urinary microalbumin concentration were more likely to have MetS (OR = 1.66, 95% CI = 1.17-2.35), hypertension (OR = 1.63, 95% CI = 1.16-2.30) and hyperglycemia (OR = 1.78, 95% CI = 1.24-2.56). No significant association was observed between urinary microalbumin concentrations and other components of MetS. The optimal cut-off points of urinary microalbumin for predicting the chance of having T2DM and MetS were 14.0 and 13.6 mg/L, respectively. CONCLUSIONS: Elevated spot urinary microalbumin, below the values defined as microalbuminuria, was associated with the chance of having T2DM and MetS.

The association between dietary fats and the incidence risk of cardiovascular outcomes: Tehran Lipid and Glucose Study.

BACKGROUND: The association between dietary fats and the risk of cardiovascular disease (CVD) is under debate. We aimed to determine the potential effects of dietary saturated fats (SFA), mono-unsaturated (MUFA) and poly-unsaturated (PUFA) fatty acids on the occurrence of CVD in an adult Asian population. METHODS: This study was conducted within the framework of the Tehran Lipid and Glucose Study on 2809 CVD-free adults, aged ≥ 19 years. Dietary intakes of fats were estimated using a validated 168-items semi-quantitative food frequency questionnaire, at baseline. Adjusted hazard ratios and 95% confidence intervals of CVD were calculated in tertile categories of dietary fats. The risk of CVD was estimated with multivariable Cox regression for the substitution of total fat or SFA with other macronutrients. RESULTS: During 10.6 years of follow up, the incidence rate of CVD events was 7.1%. Mean (± SD) age of the participants was 39 (± 14) years and 43.9% were men. Total fat, animal and plant sources of fats were not associated with risk of CVD events. No significant associations were found between total SFA, lauric acid, myristic acid, stearic acid, palmitic acid as well as MUFA and PUFA and CVD incidence. Substitutions of total fats or SFA with other macronutrients were not associated with CVD risk. CONCLUSIONS: In this study, no significant associations were found between dietary fats and CVD risk. Considering the emerging body of literature that suggests no association between fats and CVD risk, reconsideration of dietary recommendations regarding low fat diets to prevent CVD, seems to be essential.

Common Limitations and Challenges of Dietary Clinical Trials for Translation into Clinical Practices.

The progressive development of clinical and public health nutrition has long relied on dietary clinical trials (DCTs), investigating the causal relationship between diet and multiple risk factors of non-communicable and chronic diseases. DCTs are also hallmarks for establishing dietary requirements and promoting overall nutritional health among the population. Despite their critical importance in translation into public health strategies and practices, DCTs have several limitations and challenges for study design, implementation and finding interpretation. The complex nature of nutrition interventions, collinearity between diet components, multi-target effects of the interventions, diverse dietary behaviors, and food culture are the most challenging issues. Furthermore, baseline exposure and dietary status, appropriate control groups, blinding, randomization, and poor adherence undermine the effectiveness of DCTs in translation into practices. Disruptive factors will be minimized if researchers are committed to following good clinical practice (GCP) standards available for common designs of clinical trials. Planning DCTs, however, needs careful considerations for hypothesis generation, study design development, the definition of primary and secondary outcome measures, and target population.

Habitual intake of dietary L-arginine in relation to risk of type 2 diabetes: a prospective study.

BACKGROUND: There are insufficient data in case of the potential association of habitual dietary L-arginine and the risk of type 2 diabetes mellitus (T2DM) incidence. Here we aimed to examine the potential effect of dietary L-arginine on the T2DM incidence. METHODS: For this cohort study, 2139 T2DM-free adults from the participations of Tehran Lipid and Glucose Study (TLGS) were recruited. Follow up period was approximately 5.8 years. Daily intakes of protein and L-arginine were estimated using a validated food frequency questionnaire with 168 food item. Hazard Ratios (HRs) and 95% confidence intervals (CIs), adjusted for sex, age, smoking, diabetes risk score, physical activity levels, and total energy intakes as well as carbohydrate, fiber, fats and lysine, were calculated for L-arginine as both absolute intake and its ratio from total protein. RESULTS: Mean (±SD) age of the participants was 38.9 (±12.6) years and 54.6% were women. Mean (±SD) intake of dietary protein and L-arginine was 77.2 (±22.4) and 4.05 (±1.50) g/d, respectively. An increased risk of T2DM (HR = 2.71, 95% CI = 1.20-6.09) was observed among participants with higher intakes of L-arginine (median intake of > 5.4 vs. 2.69 g/d). Total protein intake and the ratio of L-arginine to total protein intakes were not related to incidence of T2DM in both crude and adjusted models. CONCLUSION: We found that higher dietary L-arginine levels may increase risk of T2DM and it may have an independent role in T2DM development.

Effects of Ramadan intermittent fasting on leptin and adiponectin: a systematic review and meta-analysis.

OBJECTIVES: Ramadan intermittent fasting may affect whole-body metabolism by affecting appetite-related hormones. This systematic review and meta-analysis aimed to clarify the possible effects of Ramadan intermittent fasting on the main hormones regulating appetite and satiety, including leptin and adiponectin. METHODS: All English language papers in the PubMed, Scopus, and Embase databases were searched using the keywords "Ramadan fasting", "adiponectin", and "leptin", up to 2020. Data extraction was conducted based on the main data of the studies; the primary outcomes of the analysis were mean changes of adiponectin and leptin levels during the holy month of Ramadan in fasted subjects. MAIN RESULTS: Data of 16 eligible studies, conducted between 2003 and 2020, were included in the systematic review. Of these, 10 studies with complete data on leptin and adiponectin were included in the meta-analysis. A significant decrease in leptin levels was observed after Ramadan fasting (WMD = -2.28 ng/ml, 95% CI = -3.72, -0.84). Ramadan fasting had no significant effect on adiponectin levels (WMD = 2.19 ng/ml, 95% CI = -0.29, 4.67). Sub-group analysis demonstrated a greater decrease in leptin levels among normal-weight subjects compared to those of overweight/obese subjects (WMD = -4.67 ng/ml, 95% CI = -6.03, -3.31 vs. WMD = -3.43 ng/ml, 95% CI = -5.69, -1.17). CONCLUSION: Ramadan fasting may decrease leptin levels, especially in normal-weight subjects. There was high heterogeneity, which may be explained by the differences between the wide ranges of study conditions.

Urinary sodium-to-potassium ratio: a simple and useful indicator of diet quality in population-based studies.

BACKGROUND: Current evidence regarding the prognostic relevance of urinary sodium-to-potassium ratio (Na-to-K ratio), as an indicator of diet quality is limited. This study was conducted to investigate whether urinary Na-to-K ratio could be related to habitual dietary patterns, in a general population. METHODS: This study was conducted in the framework of the Tehran Lipid and Glucose Study (2014-2017) on 1864 adult men and women. Urinary Na and K concentrations were measured in the morning spot urine samples. Dietary intakes of the participants were assessed using a validated 147-item Food Frequency Questionnaire (FFQ) and major dietary patterns were obtained using principal component analysis. Mediterranean dietary pattern and Dietary Approaches to Stop Hypertension (DASH) score, were also calculated. Multivariable-adjusted linear regression was used to indicate association of dietary patterns and urinary Na-to-K ratio. RESULTS: Mean (± SD) age of participants was 43.7 ± 13.9 years and 47% were men. Mean (± SD) urinary Na, K and the ratio was 139 ± 41.0 and 57.9 ± 18.6 mmol/L, 2.40 ± 0.07, respectively. Higher urinary Na-to-K ratio (> 2.37 vs. < 1.49) was related to lower intakes of vegetables (282 vs. 321 g/day), low-fat dairy (228 vs. 260 g/day) and fruits (440 vs. 370 g/day). Western dietary pattern was related to higher urinary Na-to-K ratio (ß = 0.06; 95% CI 0.01, 0.16). Traditional dietary pattern, Mediterranean and DASH diet scores were inversely associated with urinary Na-to-K ratio (ß = - 0.14; 95% CI - 0.24, - 0.11, ß = - 0.07; 95% CI - 0.09, - 0.01, ß = - 0.12; 95% CI - 0.05, - 0.02, respectively). CONCLUSIONS: Spot urinary Na-to-K ratio may be used as a simple and inexpensive method to monitor diet quality in population-based epidemiological studies.

Effect of inorganic nitrate on metabolic parameters in patients with type 2 diabetes: A 24-week randomized double-blind placebo-controlled clinical trial.

AIM: In this randomized placebo-controlled clinical trial, effect of oral inorganic nitrate (NO3-) on metabolic parameters was assessed in patients with type 2 diabetes mellitus (T2DM). METHODS: Seventy-four eligible patients with T2DM were randomly assigned to NO3--rich beetroot powder (5 g/d contains ~250 mg NO3-) and placebo groups to complete intervention over a 24-week period. Blood HbA1c, fasting serum glucose, insulin, C-peptide, as well as lipid profile were assessed at baseline and again at weeks 4, 12, and 24; indices of insulin resistance were also calculated. To assess safety of long-term oral NO3-, liver and renal function tests were measured. An intention-to-treat approach was used for data analysis. To compare effect of intervention over time between the groups (time×group), repeated measures generalized estimating equation (GEE) linear regression models were used. RESULTS: Mean age of the participants was 54.0 ± 8.5 (47.9% were male) and mean duration of diabetes was 8.5 ± 6.1 years. A total of 64 patients (n = 35 in beetroot group and n = 29 in placebo group) completed at least two visits and were included in the analyses. No significant difference was observed between the groups for glycemic and lipid parameters over time. Liver and renal function tests, as safety outcome measures, showed no undesirable changes during the study follow-up. CONCLUSION: Supplementation with inorganic NO3- had no effect on metabolic parameters in patients with T2DM.

Functional properties of beetroot (Beta vulgaris) in management of cardio-metabolic diseases.

Red beetroot (Beta vulgaris), as a naturally occurring root vegetable and a rich source of phytochemicals and bioactive compounds, is known for its beneficial roles in the improvement of several clinical and pathologic outcome. Chronic and acute beetroot juice supplementation, as a cost-effective strategy, is proposed to hold promises in controlling diabetes and insulin hemostasis, blood pressure and vascular function, renal health and the possible effect on microbiome abundance. The secondary outcome and physiological response of microbiome abundance modulation included the non- significant fluctuation of systolic and diastolic blood pressures. Also, some studies have suggested a reno-protective property of beetroot juice that is associated with the reduction of mortality rate and favorable changes in kidney's functional parameters among patients with renal disorders. Similarly, it is shown that the persistent consumption of beetroot juice effectively postpones the postprandial glycemic response and decreases the blood glucose peak. The significant blood pressure lowering effect has been seen among normotensive subjects, which tend to be more considerable among hypertensive individuals and progressive among overweight adults. Within this context, this review aims to provide a comprehensive overview on the therapeutic applications of beetroot juice in metabolic disorders and theirs underlying mechanisms. Despite the inconsistencies in the set of results from the reviewed studies, there is no doubt that further contributing factors must be investigated more deeply in future studies.

Elevated serum levels of aminotransferases in relation to unhealthy foods intake: Tehran lipid and glucose study.

BACKGROUND: Abnormal levels of liver enzymes, particularly aminotransferases, are prognostic features of non-alcoholic fatty liver disease (NAFLD). Considering the important role of dietary intakes in development of NAFLD, we aimed to determine possible association of unhealthy foods (fast foods, soft drinks, sweet and salty snacks) consumption with elevated levels of aminotransferases. METHODS: This cross-sectional study was conducted within the framework of sixth phase of the Tehran Lipid and Glucose Study (2014-2017), on 187 adult men and 249 adult women (19-70 y). Usual intakes of unhealthy foods (kcal/week) were measured using a validated semi-quantitative 147-items food frequency questionnaire. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) were measured. Multivariable logistic regression models were used to estimate the odds of elevated aminotransferases in each tertile of energy-dense unhealthy foods. RESULTS: Mean age of participants was 44.44 ± 15.09 years, 43% of participants were men. Higher consumption of fast foods (> 11.39% kcal/week) was associated with elevated ALT to AST ratio (OR: 3.27; 95% CI: 1.90-5.63) and elevated ALT (OR: 2.74; 95% CI: 1.57-4.76). Also, each 1 SD increased energy intakes from fast foods was related to increased chance of having elevated ALT and ALT to AST ratio by 35% (OR: 1.35; 95% CI: 1.08-1.68, OR: 1.35; 95% CI: 1.10-1.66, respectively). There was no significant association between consumption of soft drinks, sweet or salty snacks and elevated aminotransferases. CONCLUSIONS: Higher intakes of energy from fast foods seems to be associated with an elevated serum levels of ALT and ALT to AST ratio, as indicators of development of NAFLD.

Effects of Ramadan intermittent fasting on lipid and lipoprotein parameters: An updated meta-analysis.

AIMS: This systematic review and meta-analysis aimed to clarify several aspects of intermittent fasting during the month of Ramadan on lipid and lipoprotein levels in apparently healthy subjects. DATA SYNTHESIS: We searched PubMed, Scopus, and Embase databases and the reference lists of previous reviews, up to Feb 2019 for studies that investigated the effects of Ramadan fasting on fasting levels of triglycerides (TG), total cholesterol (TC), HDL-C, LDL-C, and VLDL-C among healthy subjects including pregnant women and athletic subjects. Studies were selected for quality assessment, meta-analyses, subgroup analyses, and meta-regressions; data of 33 eligible studies, conducted between 1978 and 2019, were included in the analysis. RESULTS: Intermittent fasting showed no significant effect on circulating TG (WMD = -0.38 mg/dl, 95% CI = -5.33, 4.57), TC (WMD = -1.58 mg/dl, 95% CI = -6.04, 2.88), and LDL-C levels (WMD = 1.85 mg/dl, 95% CI = 0.77, 2.92). Overall, HDL-C (WMD = -2.97 mg/dl; 95% CI = -6.43, 0.48 mg/dl) and VLDL-C (WMD = -1.41 mg/dl; 95% CI = -2.73, -0.10 mg/dl) significantly decreased after Ramadan fasting. A significant increase in LDL-C levels was observed in athletic subjects (WMD = 2.97 mg/dl; 95% CI = 0.80, 5.13) and apparently healthy subjects (WMD = 1.81 mg/dl; 95% CI = 0.55, 3.07). Change in TG levels was associated with age (ß = -0.94, P = 0.043), its baseline values (ß = -0.44, P = 0.001), and weight change during the fasting period (ß = -0.57, P = 0.032). CONCLUSION: Ramadan fasting may be accompanied by a moderate improvement of lipid and lipoprotein parameters, especially HDL-C levels; fasting appears to be more beneficial for men and athletic subjects.

Tea, coffee, caffeine intake and the risk of cardio-metabolic outcomes: findings from a population with low coffee and high tea consumption.

BACKGROUND: This study aimed to assess the potential effects of long-term intake of caffeine and habitual consumption of coffee and tea on the occurrence of cardio-renal events among an Iranian population with low coffee and high tea consumption. METHODS: Adult participants of the Tehran Lipid and Glucose Study (2006-2008 to 2012-2014) who met the study inclusion criteria, were recruited. Habitual dietary intakes were assessed using a validated food frequency questionnaire. Demographics, anthropometrics, blood pressure, and biochemical variables were evaluated at baseline and during follow-up examinations. Multivariate Cox proportional hazard and logistic regression models adjusted for potential confounders were used to estimate the risk of cardiovascular disease (CVD), hypertension (HTN) and chronic kidney disease (CKD). RESULTS: During median 6 years of follow-up, the incidence rate of CVD outcomes, HTN, and CKD were 3.3%, 15.5%, and 17.9%, respectively. The risk of CVD was increased more than two-fold in the highest tertile of tea consumption (HR = 2.44, 95% confidence interval, CI = 1.40-4.27; P for trend = 0.001), and caffeine intakes (HR = 2.22, 95% CI = 1.23-4.01; P for trend = 0.005). A 42% lower incidence of CVD was observed in coffee drinkers, compared to non-drinkers (HR = 0.58, 95% CI = 0.36-0.93; P for trend = 0.023). No significant association was observed between tea, coffee or caffeine intakes and the risk of HTN or CKD. CONCLUSIONS: Findings of our study support previous data regarding the protective effects of coffee on CVD. Contrary to the previous studies, we found that higher intakes of tea and caffeine, mainly originated from tea in our population, may increase risk of CVD events. It may be related to the type of tea and its preparation methods, additives or artificial colors in tea consumed in Iran, and sweets or sugar that mostly consumed accompanied by tea. Also, genetic variants of the liver enzymes may modify the association of dietary caffeine sources and incidence of CVD. Further prospective studies with incorporation of different population with different dietary habits and genetic backgrounds are needed to clarify the contradictions.

The Association between Dietary Fat Pattern and the Risk of Type 2 Diabetes.

Despite several studies examining single dietary fats on type 2 diabetes (T2D) incidence, little is known about the effects of multiple fatty acids on the risk of T2D. We aimed to address this question in the Tehran Lipid and Glucose Study (TLGS) population. Dietary intakes of participants without T2D (n=2,139) were assessed using the validated food frequency questionnaire. To assess the risk of T2D after 6 years of follow-up, we used multivariate Cox proportional hazard regression models. Three major dietary fat patterns were: (1) high amounts of dietary cholesterol, saturated fats, oleic acid, linoleic acid, linolenic acid, and trans fats; (2) high amounts of long-chain polyunsaturated fats; and (3) high amounts of dietary cholesterol and saturated fats. Dietary total fat intake hazard ratio [HR=1.31, 95% confidence interval (CI)=0.77~2.23 and HR=0.69, 95% CI=0.27~1.76, in the second and third tertile, respectively] was not related to the development of T2D. Animal- and plant-based dietary fat intakes were additionally not related to the risk of T2D. After adjustment for confounding variables, there was no significant association between dietary fat pattern score and T2D incidence. Whereas, the third pattern had a borderline negative association with diabetes development (HR=0.56, 95% CI=0.29~1.07). These novel data suggest that dietary fat composition may modify the risk of T2D incidence.

Dietary total antioxidant capacity and incidence of chronic kidney disease in subjects with dysglycemia: Tehran Lipid and Glucose Study.

PURPOSE: We aimed to investigate the association of dietary total antioxidant capacity (TAC) with incidence of CKD in subjects with dysglycemia. METHODS: We followed-up 1179 subjects aged ≥30 years with dysglycemia from the Tehran Lipid and Glucose Study (TLGS) for 3 years, who were initially free of CKD. Dietary intakes of TAC, vitamin C, vitamin E, and ß-carotene were assessed by a food-frequency questionnaire at the baseline. Dietary TAC was estimated using the oxygen radical absorbance capacity method. Estimated glomerular filtration rate (eGFR) was calculated, using the Modification of Diet in Renal Disease Study equation and CKD was defined as eGFR <60 mL/min/1.73 m2. Odds ratios (ORs) using multivariable logistic regression were reported for the association of incident CKD with dietary TAC. RESULTS: A total of 197 (16.7%) cases of incident CKD were recorded after 3 years of follow-up. After adjustment for age, sex, smoking, physical activity, body mass index, hypertension, and total energy intake, the top tertile of dietary TAC compared to the bottom was associated with 39% [95% confidence interval (CI) = 0.40-0.93] lower risk of incident CKD (P for trend = 0.025). Furthermore, the highest tertile of vitamin C intake compared to the lowest risk of incident CKD was decreased (OR 0.60; 95% CI 0.38-0.93, P trend 0.023). Intakes of vitamin E and ß-carotene were not significantly associated with incident CKD risk. CONCLUSION: Our findings suggest that diets high in TAC are associated with a lower risk of incident CKD among subjects with hyperglycemia after 3 years of follow-up.