Waist to height ratio as a simple tool for predicting mortality: a systematic review and meta-analysis.

BACKGROUND: The association of central obesity with higher rates of mortality is not well studied. This study evaluates the association between waist-to-height ratio (WHtR), as a measure of central obesity, with mortality. METHODS: Documents were retrieved from PubMed, Web of Science, Scopus, and Google Scholar databases until May 2022. Data were extracted from cohort studies reporting effect size (hazard ratio (HR)) regarding the association between WHtR as a continuous (per 1 SD increment) or categorical (highest/lowest) measure and all-cause and cause-specific mortality. Screening of included studies was performed independently by two authors. Moreover, the quality assessment of included studies was performed based on the Newcastle-Ottawa assessment scale. Finally, random effect meta-analysis was performed to pool the data, and the outcomes' certainty level was assess based on the GRADE criteria. RESULTS: Of the 815 initial studies, 20 were included in the meta-analysis. Random effect meta-analysis showed that in the general population, the all-cause mortality HRs for categorical and continuous measurements of WHtR increased significantly by 23% (HR:1.23; 95% CI: 1.04-1.41) and 16% (HR:1.16; 95% CI: 1.07-1.25), respectively. Moreover, the hazard of cardiovascular (CVD) mortality increased significantly for categorical and continuous measurements of WHtR by 39% (HR:1.39; 95% CI: 1.18-1.59) and 19% (HR:1.19; 95% CI: 1.07-1.31). The quality assessment score of all included studies was high. CONCLUSIONS: Higher levels of WHtR, indicating central obesity, were associated with an increased hazard of CVD and all-cause mortality. This measure can be used in the clinical setting as a simple tool for predicting mortality.

Dietary carbohydrate quality index and cardio-metabolic risk factors.

Introduction: Improving the quality of diet is known as one of the practical ways to reduce cardio-metabolic risk factors (CMRFs). The carbohydrate quality index (CQI) is a relatively new index to evaluate diet quality. It is calculated based on the ratio of solid carbohydrates to total carbohydrates, dietary fibre intake, glycemic index and the ratio of whole grains to total grains. This systematic review and meta-analysis was designed to investigate the association between dietary CQI and CMRFs. Methods: In this systematic review, some international databases, including Scopus, PubMed, EMBASE, Web of Science, and Google Scholar up to July 2022, were searched according to appropriate keywords. All observational studies with an English full text assessing the association between the dietary CQI and CMRFs were included. Two researchers independently extracted the data and assessed the quality of the articles with the Newcastle-Ottawa Scale. Random/fixed-effect meta-analysis was used to pool standardized mean difference (SMD) as an effect size. Results: 11 studies with a total of 63962 subjects were found to be eligible and included in the qualitative synthesis; only BMI, WC and metabolic syndrome reached the threshold of 3 reports with the same effect size and thus only 5 were included in the meta-analysis. The main finding of the included studies was that there were inverse associations between CQI and CMRFs, mainly obesity, glucose metabolism indices, and blood pressure. In the five studies included in the random effect meta-analysis, the association between CQI and body mass index (SMD: 0.45, 95%CI: -0.12, 1.01), waist circumference (SMD: -0.09, 95%CI: -0.34, 0.15) and metabolic syndrome (SMD: 0.63, 95%CI: -0.01, 1.28) was not statistically significant. Conclusion: Although the qualitative findings support the positive association of CQI with CMRFs, the evidence is insufficient to conclude robust findings. Further observational and interventional studies are needed to clearly elucidate this association.

Dietary phytochemical index and its relationship with diabetic sensorimotor polyneuropathy: a case-control study.

Phytochemicals are compounds found in fruits, vegetables, whole grains, nuts and legumes that are non-nutritive but have bioactive properties. A high intake of these compounds is essential for optimal health and disease prevention. No study has investigated the association between Dietary Phytochemical Index (DPI) and polyneuropathy in patients with diabetes. This study aimed to examine the association between DPI and Diabetic Sensory-motor Polyneuropathy (DSPN) in a case-control study. In this case-control study, a total of 185 diabetic patients with DSPN (case group) and 185 sex- and age-matched diabetic patients without neuropathy (control group) were enrolled in this study. Participants were 30-60 years old. A validated food frequency questionnaire was used to measure the dietary intake of all participants. Daily energy derived from phytochemical-rich foods was used to calculate the DPI score. Toronto clinical neuropathy score was applied to define DSPN. Anthropometric data and fasting blood glucose levels were measured using standard methods. The Binary logistic regression was used to estimate Crude and multivariable-adjusted OR (95% CI) for DSPN across tertiles of DPI for the whole population. In the crude model, there was a significant trend across the tertile of DPI (OR highest vs. lowest tertile of DPI = 0.33; 95%CI 0.18, 0.52; P-trend < 0.001). After controlling for age, sex, and energy, a significant reverse association was observed between DPI and DSPN (OR highest vs. lowest tertile of DPI = 0.27; 95%CI 0.15, 0·48; P-trend < 0.001). Moreover, after adjusting for a wide range of confounding variables such as energy intake, physical activity, education, smoking status, and HbA1c, participants in the third tertile of DPI had 75% reduced odds for DSPN (95%CI 0.14, 0.45; P-trend < 0.001). Finally in the full adjusted model, after further adjustment for BMI, observed significant association was remained (OR highest vs. lowest tertile of DPI: 0.24; 95% CI 0.13, 0.14; P-trend < 0.001). Higher intakes of phytochemical-rich foods are associated with lower odds of DSPN.

Association of normal weight obesity phenotype with inflammatory markers: A systematic review and meta-analysis.

Background: Individuals with normal weight could suffer from obesity based on their body fat percentage (also known as normal weight obesity (NWO)), thus being at risk of significant morbidity and mortality compared to the general population. It seems that inflammatory pathways and chronic inflammation are significant contributors to the pathogenicity of NWO. This study aimed to assess and pool the association of proinflammatory and anti-inflammatory cytokines with NWO. Methods: In this systematic review and meta-analysis, online international databases (PubMed, Scopus, EMBASE, Web of Science, and Google Scholar) were searched until August 2022. All observational studies with an English full text comparing the mean levels of proinflammatory and anti-inflammatory cytokines (e.g., C-reactive protein (CRP), various types of interleukins (IL) s, tumor necrosis factor-alpha (TNF)) and white blood cell (WBC) count, in subjects with NWO and "normal weight non-obese (NWNO)" were included. Two researchers independently screened, reviewed and assessed the quality of included studies. The remaining articles' data were extracted post-screening. The heterogeneity between studies was assessed using the I2 and Cochran's Q tests. A random effect model meta-analysis was used to pool the standardized mean difference (SMD) as an effect size. Results: From the initial 559 studies, 21 and 19 were included in the qualitative and quantitative synthesis, respectively. In the systematic review, 8 studies reported a significant association between various proinflammatory cytokines (CRP, IL6, IL1ß, and TNFα) and NWO. According to random-effect meta-analysis, the association between NWO with CRP (SMD: 0.60, 95% CI: 0.30, 0.91) and IL6 (SMD: 0.90, 95%CI: 0.14, 1.66) was statistically significant. Moreover, the mean level of TNFα in subjects with NWO and NWNO did not differ significantly (SMD: 0.67, 95% CI: -0.36, 1.70). Conclusion: The findings of this study show that NWO was associated with high levels of CRP and IL6. Therefore, inflammatory pathways may play a role in the pathogenicity of NWO.

Association between Dietary Inflammatory Index Scores and Diabetes Sensorimotor Polyneuropathy in Patients with Type 2 Diabetes Mellitus: A Case-Control Study.

Background: Diabetes sensorimotor polyneuropathy (DSPN) is a common complication of diabetes. Diet has been previously related to DSPN. However, no studies have investigated the relationship between the inflammatory potential of the whole diet and DSPN. So, we aimed to examine the association between dietary inflammatory index (DII) and DSPN in Iranian adults. Methods: A total of 185 subjects with DSPN and 185 sex- and age-matched controls were selected in this case-control study. A 168-item validated food frequency questionnaire (FFQ) was used to assay dietary intakes. DII was calculated based on the developed formula. The Toronto clinical neuropathy score was applied to define DSPN. Binary logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (95% CIs) of DII in relation to DSPN. Results: Mean values of age and BMI for all the participants were reported as 50.79 and 28.60, respectively. Also, the median (IQR) of DII for all the participants was estimated as -0.091 (-0.93, 1.07). Our findings suggest that participants in the highest quartile of the DII had higher odds of DSPN (OR = 1.76; 95% CI: 1.03, 3.36) (p-trend = 0.01) compared to subjects in the lowest quartile of DII scores after adjustment for age and sex. Additionally, a strong association was observed after adjusting for energy intake, physical activity, education, smoking status, economic status, marital status, job, BMI, and WC in model 2 (OR = 2.23, 95% CI = 1.13-4.39) (p-trend = 0.0048). Conclusion: Higher DII score was associated with an increased risk of DSPN. Therefore, it is possible that a diet rich in anti-inflammatory nutrients and foods could improve and prevent DSPN.

Association of dietary acid-base load and diabetic sensorimotor polyneuropathy in patients with type 2 diabetes mellitus: A case-control study.

OBJECTIVES: The higher acid-forming potential of a diet, could be associated with diabetes. No study has been done to investigate the association between Dietary Acid Load (DAL) and polyneuropathy in patients with diabetes. This study aimed to examine the linkage between the DAL and Diabetic Sensory-motor Polyneuropathy (DSPN) in a case-control study. METHOD: This case-control study was performed at Diabetes Research Center, Endocrinology and Metabolism Clinical Sciences Institute, in Kermanshah, Iran between April 2020 and August 2020. A total of 185 subjects with DSPN and 185 sex- and age-matched people in the control group (30-60 years old) participated in this study. Dietary intakes of all people were assessed using a validated food frequency questionnaire. DAL was evaluated through the Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP). Toronto clinical neuropathy score was applied to define DSPN. Anthropometrics data, and fasting blood glucose levels were measured. RESULTS: The Binary logistic regression was used to estimate the Odds Ratios (ORs) and 95% Confidence Intervals (95% CIs) of NEAP and PRAL in relation to DSPN. After adjustment for age, sex, energy people with higher DAL had increased odds for DSPN (ORPRAL = 3.0; 95%CI: 1.8-5.1; p-trend <0.001 and ORNEAP = 3.8; 95%CI: 2.2-6.5; p-trend <0.001). Additional adjustment for physical activity, education, smokers, and economic status strengthened the association (ORPRAL = 3.3; 95%CI:1.9-5.8; p-trend <0.001 and ORNEAP = 3.7; 95%CI: 2.2-6.5; p-trend<0.001). Finally, after additional adjustment for BMI in the full adjustment model, compared to people in the first tertile of DAL, participants in the third tertile had approximately 3.5 times significant greater odds for DSPN (ORPRAL = 3.3; 95%CI: 1.9-5.7; p-trend <0.001 and ORNEAP = 3.6; 95%CI: 2.2-6.2; p-trend<0.001). CONCLUSION: Patients with a higher acidic diet had greater odds for DSPN compared to people with lower DAL.