Energy and macronutrient intake heritability: A systematic review and meta-analysis of twin and family-based studies.

BACKGROUND/AIMS: The current meta-analysis aimed to examine the heritability and familial resemblance of dietary intakes, including energy and macronutrients in both twin and family-based studies. METHODS: The online literature databases, including PubMed, Scopus, and Web of Science were searched comprehensively until 2023 to identify the relevant studies. The heritability index in family studies was h2 and the heritability indices for twin studies were h2, A2, and E2. Three weighted methods were used to calculate the mean and SE of heritability dietary intakes. RESULTS: Eighteen papers including 8 studies on familial population and 12 for twin population studies were included in the present meta-analysis. The heritability of dietary intakes in twin studies (range of pooled estimated h2, A2, and E2 was 30-55%, 14-42%, and 52-79%, respectively) was higher than family studies (range of pooled estimated h2 = 16-39%). In family studies, the highest and lowest heritability for various nutrients was observed for the fat (%Kcal) (h2 range:36-38%) and carbohydrate in g (h2 range:16-18%), respectively. In twin studies, based on mean h2, the highest and lowest heritability for various nutrients was reported for the fat (%Kcal) (h2 range:49-55%) and protein intake in g (h2 range:30-35%), respectively. Also, based on the mean of A2, the highest and lowest heritability was observed for carbohydrates (% Kcal) (A2 range:42-42%), and protein (% Kcal) (A2 range:14-16%), respectively. Furthermore, in twin studies, the highest and lowest mean of E2 was shown for saturated fats (E2 range:74-79%) and energy intake (E2 range:52-57%), respectively. CONCLUSION: Our analysis indicated that both environmental factors and genetics have noticeable contributions in determining the heritability of dietary intakes. Also, we observed higher heritability in twins compared to family studies.

Cigarette smoking and cardiovascular disease incidence and all-cause mortality: the modifying role of diet quality.

BACKGROUND: This study examines the potential long-term joint association between smoking and diet quality as modifiable risk factors concerning cardiovascular diseases (CVDs) incidence and all-cause mortality among current and former smokers. METHODS: The study followed 955 smokers from the third and fourth examinations of the Tehran Lipid and Glucose Study to March 2018. Dietary data was collected using a food frequency questionnaire. Three diet quality indices (DQIs) were computed at baseline: DQI-international (DQI-I), DQI-revised (DQI-R), and Mediterranean-DQI (Med-DQI). Cox proportional hazards regression models were used to determine the HR (95% CI) of the joint association between smoking and diet quality among heavy and light smokers, based on the number of cigarettes per day and pack-years, as well as between current and former smokers based on smoking habits. RESULTS: Over a follow-up period of almost eight years, 94 cases of CVDs (9.80%) and 40 cases of mortality (4.20%) were documented. The lower diet quality based on the Med-DQI was associated with a higher risk of mortality among current smokers (HR:3.45; 95%CI:1.12, 10.57). Light smokers with good diet quality, compared to heavy smokers with poor diet quality, had a lower risk of CVDs incident (HR:0.35; 95%CI: 0.15, 0.83) and all-cause mortality (HR:0.20; 95%CI:0.05, 0.77). Current smokers with good DQI had a lower risk of mortality compared to current smokers with poor DQI (HR:0.26; 95%CI:0.08, 0.80). However, this lower risk was more significant in former smokers with good DQI (HR:0.10; 95%CI:0.02, 0.45). CONCLUSIONS: Light and former smokers had a lower risk of developing CVDs and experiencing mortality. However, when coupled with a high-quality diet, this protective effect is even more pronounced.

Parent-child correlation in energy and macronutrient intakes: A meta-analysis and systematic review.

In the current study, we aimed to review the evidence from twin and family-based studies that have assessed the familial similarity in intakes of energy and macronutrients among various parent-child pairs. The online literature databases, including Web of Science, PubMed, and Scopus, were searched up to December 2022 to find potentially eligible studies. We converted Pearson's, Spearman's, or intra-class correlation coefficients to z's using Fisher's z transformation to obtain approximate normality and then calculated a mean and standard error (SE) of transformed correlation weighted by the sample sizes in the studies. We reported pooled r and 95% CI as our final results in five groups, including parent-child, mother-daughter, mother-son, father-daughter, and father-son. Twenty-one eligible studies were included in this meta-analysis, in which the sample size ranged from 33 and 4310. Our analysis showed that family resemblance in the intake of energy and macronutrients in various parent-offspring pairs was weak to moderate which could be different based on family pairs, nutrients, and studies. The highest similarity in dietary intakes was observed among the mother-daughter pair, which was for carbohydrate and protein intake, respectively. The lowest correlations in dietary intakes were found between mother-son or father-son pairs. Our meta-analysis suggested that family similarity for intakes of energy and macronutrients was not strong in parent-child pairs. The highest correlation in dietary intake was mostly found in mother-daughter pairs. The weak similarities in dietary intake among parent-child pairs indicate the noticeable effect of the environment outside the family on individuals' dietary choices.

Macronutrients quality indices and risk of metabolic syndrome and its components in Iranian adults.

BACKGROUND/AIM: Evidence from recent studies suggested that the quality of dietary macronutrients can play a possible role in predicting the risk of metabolic disorders. In the current study, we aimed to assess the association of carbohydrate quality index (CQI) and protein score with the risk of metabolic syndrome (MetS) in Iranian adults. METHODS: This prospective study was conducted within the framework of the Tehran Lipid and Glucose Study on 1738 individuals aged between 40 and 70 years old, who were followed up for a mean of 6.1 years. A food frequency questionnaire was used to determine CQI and protein scores. The multivariable adjusted Cox regression model was used to calculate the hazard ratio (HR) of MetS across quartiles of protein score and CQI, and its components. RESULTS: The mean ± standard deviation (SD) age and body mass index of the study population (42.5% men) were 49.3 ± 7.5 years and 27.0 ± 4.0 kg/m2, respectively. Mean ± SD scores of CQI and protein for all participants were 12.6 ± 2.4 and 10.3 ± 3.5, respectively. During the study follow-up, 834(48.0%) new cases of MetS were ascertained. In the multivariable-adjusted model, the risk of MetS was decreased across quartiles of CQI (HR = 0.83;95%CI:0.69-1.00, Ptrend=0.025) and protein score (HR = 0.75; 95% CI:0.60-0.94, Ptrend=0.041). Also, Of CQI components, the whole grain/total grains ratio showed a significant inverse association with the risk of MetS (HR = 0.75;95%CI:0.60-0.94, Ptrend=0.012). CONCLUSION: Our findings revealed that a dietary pattern with higher CQI and protein score may be related to a reduced risk of MetS in adults.

High-protein diet scores, macronutrient substitution, and breast cancer risk: insights from substitution analysis.

BACKGROUND: Evidence from recent studies suggested that variation in the quantity and quality of macronutrients in the diet may potentially play a role in predicting the risk of breast cancer (BC). In the current study, we aimed to assess the association of different high-protein diet scores and replacing fats and carbohydrate (CHO) with protein in the diet with the BC risk among Iranian women. METHODS: The current hospital-based case-control study was conducted on 401 participants, aged ≥ 30 years old, including 134 women in the case group who had been diagnosed with histologically confirmed BC and 267 women in the control group. Dietary intake data was collected using a validated food frequency questionnaire, and high protein diet scores were determined. Logistic regression models were used to determine the odds ratios (OR) and 95% confidence interval (CI) of BC across tertiles of high protein diet scores. Also, we assessed how substituting protein with other macronutrients affected BC odds while adjusting for the various confounding variables. RESULTS: Participants' mean ± SD of age and body mass index were 47.9 ± 10.3 years and 29.4 ± 5.5 kg/m2, respectively. The scores of high-protein-low-CHO and fat diet, high-protein and CHO-low-fat diet, and high-protein and fat-low-CHO diet in participants were 16.5 ± 3.8, 16.5 ± 6.7, and 16.4 ± 5.9, respectively. In the multivariable model, individuals in the highest tertile of high-protein-low-CHO and fat diet score (OR:0.71;95%CI:0.56-0.90) and high-protein and CHO-low-fat diet (OR:0.76;95%CI:0.60-0.97) had lower odds of BC compared to those in the lowest tertile (P < 0.05). However, no significant association was found between high-protein and fat-low-CHO diet and BC risk. Our results showed that replacing fat by protein (ORdifferences:-0.40;95%CI:-0.73,-0.07) and also replacing refined-CHO by plant protein (ORdifferences:-0.66;95%CI:-1.26,-0.07) in the diet are associated inversely with risk of BC(P < 0.05). CONCLUSIONS: The results of our study suggested that higher adherence to a high-protein-low-CHO and fat diet, characterized by a higher intake of plant proteins and a lower intake of refined grains and saturated fat can play a protective role against the odds of BC.

The association of the healthy food diversity index with the risk of non-alcoholic fatty liver disease among the adult population.

BACKGROUND AND AIM: Dietary diversity index is a useful evaluation index for examining the role of dietary pattern in predicting chronic diseases risk, including non-alcoholic fatty liver disease(NAFLD). In the present study, we aimed to examine the possible association of dietary diversity using US Healthy Food Diversity(US HFD) index and the NAFLD risk in Iranian adults. METHODS: A total of 675 individuals (225 patients with NAFLD and 450 controls) aged 20-60 years were recruited for the current case-control study. Data on dietary intakes were determined using a validated food frequency questionnaire, and dietary diversity was calculated using the US HFD index. In patients with NAFLD, an ultrasound scan of the liver was used to detect NAFLD. Logistic regression models were used to estimate the odds ratios(ORs) and 95 % confidence interval(CI) of NAFLD across tertiles of the US HFD index. RESULTS: Mean ± SD age of the study population were 38.13 ± 8.85 years. The median (interquartile) score of the US HFD index in patients with NAFLD and healthy subjects was 0.08(0.07-0.09) and 0.09(0.08-0.10), respectively. In the age and sex-adjusted model, the odds of NAFLD were considerably reduced across tertiles of the US HFD index (OR:0.48; 95%CI:0.32-0.72, Ptrend<0.001). Also, in the final model, after adjusting for age, sex, waist-to-hip ratio, smoking, physical activity, marital status, socioeconomic status, and energy intake, the odds of NAFLD were significantly reduced across tertiles US HFD index (OR:0.55; 95%CI:0.31-0.97, Ptrend<0.001). Furthermore, for each SD increase in the US HFD index, the odds of NAFLD are reduced by 23 % (OR:0.77;95%CI:0.60-0.97,P-Value<0.001). CONCLUSIONS: Our findings revealed that greater adherence to dietary pattern with a high US HFD score, defined by higher intakes of fruits, vegetables, whole grains, legumes, nuts, low-fat dairy, seeds, soya products, and plant oils may be related to reducing the odds of NAFLD.

From adolescence to adulthood: Mediterranean diet adherence and cardiometabolic health in a prospective cohort study.

BACKGROUND AND AIMS: Recent investigations suggest that specific dietary patterns during adolescence may predict cardiometabolic complications later in life. In this study, we aimed to examine the association between Mediterranean diet score (MDS) during adolescence and cardiometabolic outcomes when participants reached adulthood. METHODS AND RESULTS: This cohort study was conducted on 668 subjects, aged 10-19 years, in framework of the Tehran Lipid and Glucose Study. The MDS was determined based on eight components using a validated food-frequency questionnaire. Anthropometric measurements, fasting blood glucose (FBG), and lipid profile data were measured both at baseline and after a 6.8 ± 2.9-year follow-up. Using multivariable linear regression, we explored the association between MDS and changes in cardiometabolic risk factors. Moreover, multivariable-adjusted cox proportional hazard regression was used to estimate hazard ratios (HR) and 95 % confidence intervals (CIs) for cardiometabolic complications across MDS tertiles. The mean ± SD age of participants (43.5 % men) was 15.8 ± 2.47 years. The mean ± SD of MDS was 4.03 ± 1.56, with a median of 4.00 among all participants. Higher MDS was inversely associated with 6.8-year changes in waist circumference (WC), FBG, total cholesterol (TC), and high-density lipoprotein-cholesterol (Ptrend<0.05). Based on the HR analysis, after controlling for potential confounders, individuals in the highest tertile of MDS had a significantly lower risk of high-TC(HR = 0.36,95%CI:0.18-0.74,Ptrend = 0.004) compared to those in the lowest tertile. However, no significant association was observed between MDS and other cardiometabolic risk factors. CONCLUSIONS: Greater adolescent adherence to a Mediterranean-type diet was associated with favorable cardiometabolic factors in adulthood, including improving the levels of WC, FBG, TC, as well as reduced risk of high-TC.

The association between metabolic syndrome and insulin resistance with risk of cardiovascular events in different states of cardiovascular health status.

AIMS/INTRODUCTION: The aim was to examine the joint effect of metabolic syndrome (MetS) and insulin resistance (IR) with ideal cardiovascular health (iCVH) status on incident cardiovascular diseases (CVDs). MATERIALS AND METHODS: The study included 6,240 Iranian adults ≥30 years, free of prior cardiovascular disease. Ideal cardiovascular health was determined based on American Heart Association's Life Simple 7. Metabolic syndrome was defined according to the Joint Interim Statement Criteria, and insulin resistance was defined as HOMA-IR ≥1.85 in women and ≥2.17 in men. Multivariable Cox proportional hazard ratios (HRs) were applied to examine the impact of metabolic syndrome, and insulin resistance at various levels of iCVH status. RESULTS: During the median follow-up of 14.0 years, 909 cases of cardiovascular disease occurred. Metabolic syndrome and insulin resistance were significantly associated with incident cardiovascular disease events. In the poor and intermediate status, metabolic syndrome increased cardiovascular disease events with HRs of 1.83 and 1.57, respectively; the corresponding values for insulin resistance in the mentioned categories were 1.91 and 1.25, respectively (P values < 0.05). In the intermediate and poor iCVH status, hypertriglyceridemia was linked to a 40% and 35% higher risk of cardiovascular disease, the corresponding values for low HDL-C was 20% and 60%, respectively (P values < 0.05). Although adding metabolic syndrome, its dyslipidemia and insulin resistance to iCVH status in both poor and intermediate status significantly improve the prediction of cardiovascular disease using net reclassification improvement (P values < 0.05), the value of C-index did not change. CONCLUSIONS: Metabolic syndrome and the dyslipidemia component had a negligible but significant improvement in the prediction of cardiovascular disease among individuals with non-optimal iCVH status.

International diet quality index and revised diet quality index relationship with non-alcoholic fatty liver disease: a case-control study.

BACKGROUND/OBJECTIVES: Recent studies show the potential role of dietary quality and quantity in predicting the risk of chronic diseases, such as liver disease, therefore, in the present study, we aimed to assess the association of diet quality index International (DQI-I) and diet quality index revised (DQI-R) and their main components with the odds of non-alcoholic fatty liver disease (NAFLD) in adult populations. METHODS: The current case-control study was conducted on 225 patients with NAFLD and 450 controls. Dietary intake was assessed using a validated 168-item food frequency questionnaire, and DQI-I and DQI-R were calculated in participants. Multi-variable logistic regression was used to examine the association of DQI-I and DQI-R and their components with the odds of NAFLD. RESULTS: The mean (SD) age and BMI of participants (53% men) were 38.1 (8.8) years and 26.8 (4.3) kg/m2, respectively. In the final model, each one SD increment in the DQI-I score was associated with decreased odds of NAFLD (OR = 0.63; 95%CI = 0.40-0.98) (P = 0.040). Also, of DQI-I components, high adequacy score was related to lower odds of NAFLD (OR = 0.16; 95%CI = 0.06-0.40) (P < 0.001). Also, our findings showed that participants in the highest tertile of DQI-R score had lower odds of NAFLD compared to the lowest tertile of DQI-R (OR = 0.24; 95%CI = 0.10-0.53) (P < 0.001). Furthermore, of DQI-R components, high moderation score are linked to a lower risk of NAFLD (OR = 0.17;95%CI = 0.07-0.43) (P < 0.001). CONCLUSION: Our findings suggested that greater adherence to diet with a higher score of DQI-I and DQI-R may be associated with lower odds of NAFLD.

Dietary advanced glycation end products are associated with an increased risk of breast cancer in Iranian adults.

BACKGROUND: Dietary advanced glycation end products (AGEs) can play an important role in increasing inflammatory factors and oxidative stress as risk factors for cancers. In the present study, we aimed to assess the relationship between dietary AGEs and the risk of breast cancer (BC) in Iranian adult women. METHODS: This hospital-based case-control study includes 401 participants aged ≥ 30 years old. The cases group consisted of 134 women diagnosed with histologically confirmed BC. The control group included 267 women enrolled randomly from patients admitted to the same hospitals. Dietary intake information was determined using a validated food frequency questionnaire, and dietary AGEs intake was computed for all participants. Logistic regression models, adjusted for potential confounders, were used to determine the odds ratios (OR) and 95% confidence interval (CI) of BC across tertiles of dietary AGEs. RESULTS: The mean ± SD age and body mass index of the study population were 47.92 ± 10.33 years and 29.43 ± 5.51 kg/m2, respectively. The median (interquartile) of dietary AGEs in all individuals was 9251(7450, 11,818) kU/day. After adjusting for age, first pregnancy age, and energy intake, participants in the highest tertile of dietary AGEs intakes had higher odds of BC compared to those in the lowest tertile of dietary AGEs (OR:2.29;95%CI:1.19-4.39, Ptrend:0.012). Additionally, in the multivariable model, after adjusting for age, age at first pregnancy, energy, menopausal status, family history of cancer, anti-inflammatory drug use, Vitamin D supplementation, physical activity, body mass index, number of childbirths, and history of abortion, breastfeeding, and oral contraceptive pills use, the odds of BC were increased across tertiles of dietary AGEs intake (OR: 2.33; 95%CI: 1.18-4.60, Ptrend: 0.017). CONCLUSION: The present findings suggest that a diet with high AGEs is associated with a higher likelihood of BC in adult women.

Serum branched amino acids and the risk of all-cause mortality: a meta-analysis and systematic review.

Recently, the serum levels of branched-chain amino acids (BCAAs) have been considered as an indicator to evaluate health status and predict chronic diseases risk. This systematic review and meta-analysis aimed to assess the relationship between Serum BCAAs and the risk of all-cause mortality. We carried out a comprehensive and systematic search in various important databases, including PubMed, Scopus, and Web of Science databases to find the relevant studies published up to October 2022 with no language, design, or time limitation. We extracted the reported hazard ratio (HR) with 95% confidence interval (CI) and odds ratio (OR) with 95%CI in cohorts and case-control studies, respectively, and computed the log HR or OR and its standard error. Then, we used the random-effects model with inverse variance weighting method for the present meta-analysis, to calculate the pooled effect size. Ten observational studies, including nine cohort studies and one case-control study, were included in the present meta-analysis. The number of participants ranges from 53 to 26,711, with an age range of 18-99 years. During 6 months to 24 years of follow-up, 3599 deaths were ascertained. The pooled results indicated that there was no significant association between serum BCAAs (RR: 1.17; 95% CI 0.85-1.60), isoleucine (RR: 1.41; 95%CI 0.92-2.17), leucine (RR: 1.13; 95% CI 0.94-1.36), and valine (RR: 1.02; 95%CI 0.86-1.22) and all-cause mortality. Also, there was significant heterogeneity between studies for serum BCAAs (I2 = 74.1% and P-heterogeneity = 0.021), isoleucine (I2 = 89.4% and P-heterogeneity < 0.001), leucine (I2 = 87.8% and P-heterogeneity < 0.001), and valine (I2 = 86.6% and P-heterogeneity < 0.001). Our results suggested that the serum BCAAs and its components, including isoleucine, leucine, and valine, were not associated with the risk of all-cause mortality.

Familial resemblance and family-based heritability of nutrients intake in Iranian population: Tehran cardiometabolic genetic study.

BACKGROUND: We aimed to investigate the familial resemblance of dietary intakes, including energy and nutrients, and the family-based heritability of dietary intake in different age-sex dyads of the Tehran cardiometabolic genetic study. METHODS: This cross-sectional study was conducted on 9,798 participants, aged ≥ 18 years, with complete data in each of the third, fourth, fifth, and sixth surveys of the Tehran Cardiometabolic Genetic study, who were eligible to enter the current study based on inclusion and exclusion criteria. Nutrient intake was determined using a valid and reliable food frequency questionnaire (FFQ). FCOR command of the S.A.G.E. software was used to estimate the intra-class correlation coefficients of all relative pairs to verify the family resemblance of dietary nutrient intakes. Classical likelihood-based is used to assess the family-based heritability of dietary nutrient traits. RESULTS: There were 4338 families with a mean family size of 3.20 ± 2.89, including 1 to 32 members (2567 constituent pedigrees and 1572 singletons) and 3627 sibships. The mean ± SD age of participants was 42.0 ± 15.2 years, and 44.5% were males. The heritability of nutrient intake ranged from 3 to 21%. The resemblance degree of energy intake and most nutrients between spouses or between parents and children is weak to moderate; however, a high resemblance of intake was observed for some food components, especially among spouses, including trans fatty acids (TFAs) (r:0.70), chromium (r:0.44), fiber(r:0.35), pantothenic acid (r:0.31), and vitamin C(r:0.31). Based on our findings, the resemblance of nutrient intake in spouses was greater than in parent-offspring. The similarity in parent-offspring nutrient intake was different, and the correlation in mother-girls nutrient intakes was greater than other parent-child correlations. Also, the lowest resemblance in nutrient intake was observed among siblings. CONCLUSIONS: Our findings suggested a weak-to-moderate similarity between the nutrient intakes of parents and offspring. The resemblance degree in nutrient intake varied between different family pairs; the strongest correlation of nutrients was observed between spouses, which includes TFAs, chromium, fiber, pantothenic acid, and vitamin C. The lowest correlation of nutrients was between siblings, such as carbohydrates, thiamine, niacin, and vitamin K. An individual's nutrient intake can somewhat be influenced by genetics, family relationships, and the effects of parents, although the significant influence of environmental factors should not be ignored.

The association of serum C-peptide with the risk of cardiovascular events: a meta-analysis and systematic review.

BACKGROUND: C-peptide is considered a peptide with active function in the body, which can affect people's health. However, the results of previous studies on the possible association of C-peptide with the risk of cardiometabolic disorders have not been fully understood. This systematic review and meta-analysis aimed to investigate the association between serum C-peptide level and the risk of cardiovascular disease (CVD) events. METHODS: The various important databases, including PubMed, Scopus, and Web of Science, were searched comprehensively to November 2022 to identify the relevant studies. The HR(95% CI) or OR(95% CI) for observational studies were extracted and converted into log HR or log OR and their standard deviation(SD) was computed. A random-effects model with an inverse variance weighting method was conducted, to calculate the pooled effect size. RESULTS: Sixteen observational studies, including one case-control study, eight cohort studies, and seven cross-sectional studies were included in the current meta-analysis. The sample size ranged from 90 to 7030, with an age range from 12 to 85 years. During the follow-up time (ranging from 5 to 17 years), 4852 CVD events occurred. Based on cohort and case-control studies, the pooled results showed no significant association between serum C-peptide with CVD events risk (RR = 1.02;95%CI:0.91-1.15, I2 = 34.7%; P-heterogeneity = 0.140). For cross-sectional studies, the pooled results indicated a positive association between serum C-peptide and the odds of CVD outcomes (OR = 1.35;95%CI:1.04-1.76, I2 = 83.6%; P-heterogeneity < 0.001). CONCLUSIONS: The pooled results of the current study suggested that C-peptide level was not related to the risk of CVD events in cohort studies, however, the meta-analysis of cross-sectional studies showed a significant association between C-peptide and an increased risk of CVD events.

Serum C-peptide level and the risk of cardiovascular diseases mortality and all-cause mortality: a meta-analysis and systematic review.

Aims and background: Recently, the serum of C-peptide has been the focus of researchers as a possible predictor of mortality. However, the possible association of serum C-peptide with cardiovascular diseases (CVDs) mortality and all-cause mortality has not been clearly identified. This meta-analysis aimed to assess the relationship between serum C-peptide and the risk of CVDs mortality and all-cause mortality. Methods: A comprehensive and systematic search was performed in various important databases, including the PubMed, Web of Science, and Scopus to find relevant studies up to November 2022. The reported hazard ratio (HR) [95% confidence interval (CI)] for all studies was converted into log HR, and their SD was calculated. Then to compute the pooled HR, the random-effects model with inverse variance weighting method was performed. Results: Twenty-three studies were included in the meta-analysis. Fourteen studies reported HR for all-cause mortality, and nine studies for CVDs-related mortality. The pooled results indicate a significant association between serum C-peptide and the risk of all-cause mortality (HR: 1.22; 95% CI: 1.12-1.32, I2 = 76.8%; P-value < 0.001). Also, higher serum C-peptide was related to the increased risk of CVDs mortality (HR: 1.38; 95% CI: 1.08-1.77, I2 = 81.8%; P-value = 0.012). Conclusions: Our investigation suggested that an increased level of serum C-peptide is associated with a higher risk of both CVDs and all-cause mortality. Further, large-scale studies and sufficient samples are recommended to present a convincing link between C-peptide and the risk of CVDs and all-cause mortality. Systematic Review Registration: identifier, CRD42022364842.

Evidence of familial resemblance and family-based heritability of food intakes derived from a longitudinal cohort study.

We sought to investigate the familial aggregation and family-based heritability of dietary intakes among adults in a population-based longitudinal study of the Tehran Lipid and Glucose Study (TLSG). Total of 4359 males and 5439 females entered our study. We categorized foods into main groups based on the literature on main food groups and their subgroups among the Iranian dietary habits and food culture as follows: grains, fruits, vegetables, dairy, meats, legume, nuts, beverages, snacks, and fats. The intraclass correlation coefficients (ICC) are estimated to verify familial resemblance of dietary habits for all relative pairs and spouses. Family-based heritability is obtained using a mixed effect framework with likelihood-based approach. For almost all food groups, the correlation between parents and offsprings tended to be larger than those of siblings. Family-based heritability of food groups varies from the lowest 6.36% for snacks to the highest 25.67% for fruits, and 25.66% for legume. Our findings indicated weak-to-moderate similarities between parents' and offspring's food intakes; however, the similarity in parent-child food intakes was different, and the correlation in mother-daughter food intakes was stronger than other parent-child correlations, and almost all of dietary components showed strong family-based heritability.

Adherence to diet with higher dietary diabetes risk reduction score is associated with reduced risk of type 2 diabetes incident in Iranian adults.

BACKGROUND: The Dietary diabetes risk reduction score (DDRRS) has recently been considered by researchers as a diet quality index to predict the risk of chronic diseases, such as type 2 diabetes (T2D). In this study, we aimed to assess the association of DDRRS with T2D risk in Iranian adults. METHODS: Subjects aged ≥ 40 years without T2D (n = 2081) were selected for the current study from participants of the Tehran Lipid and Glucose Study (2009-2011) and followed for a mean of 6.01 years. We used the food frequency questionnaire to determine the DDRRS that is characterized by eight components, including higher consumption of nuts, cereal fiber, coffee, and polyunsaturated to saturated fat ratio and lower consumption of red or processed meats, trans fats, sugar-sweetened beverages, and high glycemic index foods. The multivariable logistic regression analysis was used to determine the odds ratio (ORs) and 95% confidence interval (CI) of T2D across the DDRRS tertiles. RESULTS: The mean ± SD age of individuals was 50.4 ± 8.2 years at baseline. The Median (25-75 interquartile range) DDRRS of the study population was 24(22-27). During the study follow-up, 233(11.2%) new cases of T2D were ascertained. In the age and sex-adjusted model, the odds of T2D were decreased across tertiles of DDRRS (OR = 0.68; 95%CI: 0.48-0.97, P for trend = 0.037). Based on the multivariable-adjusted model, after controlling all potential confounders, the risk of T2D is reduced across tertiles of DDRRS (OR = 0.66; 95%CI: 0.44-0.98, P for trend = 0.047). Also, higher scores (lower consumption) of red and processed meat (OR = 0.59; 95%CI: 0.39-0.88, P = 0.012) and sugar-sweetened beverages (OR = 0.49; 95%CI: 0.32-0.76, P = 0.002) as DDRRS components were associated with decreased T2D incident. CONCLUSIONS: Our findings suggested that a diet with a higher score of DDRRS may be related to reducing the risk of T2D in Iranian adults.

Dietary advanced glycation end products are associated with an increased risk of non-alcoholic fatty liver disease in Iranian adults.

BACKGROUND: Dietary advanced glycation end products(AGEs) may contribute to increased inflammation and oxidative stress as risk factors for chronic diseases such as liver disease. In the current study, we aimed to examine the possible association of dietary AGEs with the odds of non-alcoholic fatty liver disease (NAFLD) in Iranian adults. METHODS: A total of 675 participants (225 newly diagnosed NAFLD cases and 450 controls), aged 20-60 years, were recruited for this case-control study. Nutritional data were measured using a validated food frequency questionnaire, and dietary AGEs were determined for all participants. An ultrasound scan of the liver performed the detection of NAFLD in participants of the case group without alcohol consumption and other causes of hepatic disorders. We used logistic regression models, adjusted for potential confounders, to estimate the odds ratios(ORs) and 95% confidence interval(CI) of NAFLD across tertiles of dietary AGEs. RESULTS: Mean ± SD age and body mass index of the participants were 38.13 ± 8.85 years and 26.85 ± 4.31 kg/m2, respectively. The median(IQR) of dietary AGEs in participants was 3262(2472-4301). In the sex and age-adjusted model, the odds of NAFLD were increased across tertiles of dietary AGEs intake(OR:16.48;95%CI:9.57-28.40, Ptrend<0.001). Also, in the final model, after controlling for confounding effects of BMI, smoking, physical activity, marital status, socio-economic status, and energy intake, the odds of NAFLD were increased across tertiles of dietary AGEs intake(OR:12.16; 95%CI:6.06-24.39, Ptrend<0.001). CONCLUSION: Our results showed that greater adherence to dietary pattern with high dietary AGEs intake was significantly related to increased odds of NAFLD.

The association of healthy lifestyle score and risk of non-alcoholic fatty liver disease.

BACKGROUND: The combined role of important environmental factors as a single lifestyle index in predicting non-alcoholic fatty liver disease (NAFLD) risk is not fully assessed. Therefore, we aimed to investigate the association of healthy lifestyle factor score (HLS) with the odds of NAFLD in Iranian adults. METHODS: This case-control study was conducted on 675 participants, aged ≥ 20-60 years, including 225 new NAFLD cases and 450 controls. We measured dietary intake information using a validated food frequency questionnaire and determined diet quality based on the alternate healthy eating index-2010(AHEI-2010). The score of HLS was calculated based on four lifestyle factors, including a healthy diet, normal body weight, non-smoking, and high physical activity. An ultrasound scan of the liver was used to detect NAFLD in participants of the case group. Logistic regression models were used to determine the odds ratios(ORs) and 95% confidence interval(CI) of NAFLD across tertiles of HLS and AHEI. RESULTS: Mean ± SD age of the participants were 38.13 ± 8.85 years. The Mean ± SD HLS in the case and control groups was 1.55 ± 0.67 and 2.53 ± 0.87, respectively. Also, the Mean ± SD AHEI in the case and control groups was 48.8 ± 7.7 and 54.1 ± 8.1, respectively. Based on the age and sex-adjusted model, the odds of NAFLD were decreased across tertiles of AHEI (OR:0.18;95%CI:0.16-0.29,Ptrend<0.001) and HLS(OR:0.03;95%CI:0.01-0.05,Ptrend<0.001). Also, in the multivariable model, the odds of NAFLD were decreased across tertiles AHEI (OR:0.12;95%CI:0.06-0.24,Ptrend<0.001) and HLS(OR:0.02;95%CI:0.01-0.04,Ptrend<0.001). CONCLUSIONS: Our findings reported that higher adherence to lifestyle with a higher score of HLS was associated with decreased odds of NAFLD. Also, a diet with a high AHEI score can reduce the risk of NAFLD in the adult population.

The association of dietary and lifestyle indices for insulin resistance with the risk of cardiometabolic diseases among Iranian adults.

The current study aimed to examine the possible association of the dietary index for insulin resistance (DIR) and the lifestyle index for insulin resistance (LIR), determined by dietary components, body mass index, and physical activity, with the risk of cardiometabolic diseases, including insulin resistance (IR), hypertension (HTN), diabetes, and metabolic syndrome (MetS). This prospective cohort study was performed on 2717 individuals aged ≥ 19 years in the framework of the Tehran Lipid-Glucose Study. Data on nutritional intakes were assessed using a validated food frequency questionnaire. Logistic regression models were used to determine the odds ratio and 95% confidence intervals (ORs and 95% CIs) of cardiometabolic diseases across tertiles of DIR and LIR scores. During 3-years of follow-up, the incidence rate of diabetes, IR, HTN, and MetS was 3%, 13%, 13.9%, and 17%, respectively. In the multi-variables model, after controlling all potential confounders, the risk of IR(OR: 1.65, 95% CI 1.01-2.69, P-trend = 0.047), diabetes (OR: 1.95, 95% CI 1.02-3.74, P-trend = 0.058), and HTN(OR: 1.52, 95% CI 1.07-2.15, P-trend = 0.016) was increased across tertiles of DIR score. Also, the risk of IR (OR: 2.85, 95% CI 1.72-4.73, P-trend < 0.001), diabetes(OR: 2.44, 95% CI 1.24-4.78, P-trend = 0.004), HTN(OR: 1.95, 95% CI 1.35-2.81, P-trend < 0.001), and MetS (OR: 2.87, 95% CI 1.96-4.18, P-trend < 0.001) were increased across tertiles of LIR score. Our findings reported that a dietary pattern with a higher DIR score and a lifestyle with a higher LIR score might be related to increased cardiometabolic disorders, including diabetes, HTN, Mets, and IR in Iranian adults.

The association of dietary glycemic index and glycemic load with the risk of insomnia in the adult population.

BACKGROUND: A dietary pattern with a high glycemic index (GI) and glycemic load (GL) can be a precursor to sleep disorders that link to many chronic diseases. We aimed to assess the association of dietary GI and GL with the risk of insomnia in Iranian adults. METHODS: A total of 111 newly diagnosed insomnia cases and 333 controls aged 18-60 years were included in this case-control study. The participants' dietary intakes were collected using a valid and reliable food frequency questionnaire. The diagnosis of insomnia in subjects was performed by a neurologist using the Insomnia Severity Index (ISI) questionnaire. Multivariable logistic regression models, adjusted for the potential confounders, were used to determine the risk of insomnia according to tertiles of dietary glycemic indices. RESULTS: The mean (SD) age and BMI of the study population (78.6% female) were 31.8 (10.0) years and 24.70 (3.62) kg/m2, respectively. The median (IQR) of dietary GI and GL in subjects was 62.7 (57.0-68.6) and 213.5(167.4-268.5), respectively. Based on the multivariable-adjusted model, after controlling for age, sex, physical activity, obesity, smoking, socioeconomic score, general health questionnaire (GHQ) score, and dietary energy intake, the odds of insomnia were increased across tertiles of dietary GL[(OR:2.72,95%CI:1.10-6.70),(Ptrend = 0.017)], however, no significant association was observed between high GI diet and insomnia risk [(OR:1.38,95%CI:0.77-2.47),(Ptrend = 0.298)]. CONCLUSIONS: Our results revealed that greater adherence to dietary pattern with high GL could be increased the odds of insomnia in Iranian adults.