Physical Activity and Insulin Resistance in 6,500 NHANES Adults: The Role of Abdominal Obesity

Relationship between life's essential 8 and the risk of gestational diabetes among us adults

OBJECTIVE

The purpose of this study is to explore the relationship between Life's Essential 8 (LE8) and the risk of gestational diabetes among US adults.

METHOD

We used National Health and Nutrition Examination Surveys 2007-2018 data to perform this study. LE8 scores comprised 4 health behaviors (diet, physical activity, nicotine exposure, and sleep duration) and 4 health factors (BMI, non-high-density lipoprotein [HDL] cholesterol, blood glucose, and blood pressure). Then, LE8 were categorized into low CVH (0 to 49 scores), moderated CVH (50 to 79 scores), and high CVH (80 to 100 scores). Weighted multivariate Logistic regression analysis model were used to estimate the relationship between LE8 and gestational diabetes.

RESULT

A total of 3,189 participants were included, and the portion of gestational diabetes was 15.33%, 11.46%, 7.71% in low CVH, moderate CVH, and high CVH, respectively. Adjustment for covariates, we found that high CVH (OR: 0.49, 95%CI: 0.29-0.83, p = 0.01) was associated with decreased of gestational diabetes, not moderate CVH (OR: 0.78, 95%CI: 0.50-1.20, p = 0.25). This inverse associations were dose-response dependent (p-nonlinear = 0.982). This inverse associations were significant in subgroup. Significant interaction between CVH and family diabetes with the risk of gestational diabetes was found (P for interaction = 0.04). High CVH (OR: 0.357, 95%CI: 0.176-0.724, p = 0.005) could significantly decrease the risk of gestational diabetes in the population with family diabetes. The results were generally robust in sensitivity analyses after excluding of ASCVD participants.

CONCLUSION

The high CVH could decrease the risk of gestational diabetes, especially in the population of family diabetes.

U-shaped association of serum vitamin A concentrations with all-cause mortality in patients with NAFLD: results from the NHANES database prospective cohort study

Background

Previous studies have demonstrated a significant association between serum vitamin A concentration and non-alcoholic fatty liver disease (NAFLD) development. However, the long-term prognostic implications of serum vitamin A in patients with NAFLD remain underexplored. This study aims to investigate whether there exists a correlation between serum vitamin A concentrations and overall mortality among subjects diagnosed with NAFLD.

Methods

To investigate the association between serum vitamin A concentrations and NAFLD outcomes, we conducted prospective cohort studies using data from the 1999-2006 and 2017-2018 National Health and Nutrition Examination Survey (NHANES). We utilized a multivariate Cox regression model to explore the relationship between serum vitamin A levels and all-cause mortality. Survival curves related to serum vitamin A were constructed using the Kaplan-Meier method. Additionally, the restricted cubic splines (RCS) method was applied to examine potential nonlinear relationships between serum vitamin A concentrations and all-cause mortality of NAFLD.

Results

Over a median follow-up period of 10.3 years, a total of 1,399 all-cause deaths were recorded. The weighted average concentration of serum vitamin A was 61.48 ± 0.37 μg/dL. After adjusting for potential confounders, a significant U-shaped relationship was identified between serum vitamin A concentrations and the risk of all-cause mortality in NAFLD patients. This relationship was particularly pronounced in men and elderly individuals aged 60 to 85.

Conclusion

Our study reveals a significant non-linear relationship between serum vitamin A concentrations and the risk of all-cause mortality in patients with NAFLD. These findings underscore the importance of monitoring and maintaining optimal serum vitamin A levels to potentially improve survival outcomes in NAFLD patients.

Joint association of weight-adjusted-waist index and physical activity with insulin resistance in adolescents: a cross-sectional study

BACKGROUND

The weight-adjusted waist index (WWI) is a recently developed obesity metric, and the aim of this study was to investigate the relationship between physical activity (PA) and WWI and the homeostasis model assessment of insulin resistance (HOMA-IR) in adolescents, as well as the joint association of HOMA-IR.

METHODS

This study was based on the National Health and Nutrition Survey conducted between 2013 and 2016 and included 1024 adolescents whose median age was 15.4. Multivariate linear regression was used to examine the associations between HOMA-IR and PA and WWI. Using generalized additive models, a potential nonlinear link between WWI and HOMA-IR was evaluated. Subgroup analysis was also carried out.

RESULTS

The fully adjusted model revealed a positive association (β: 0.48, 95% CI: 0.43, 0.53) between the WWI and HOMA-IR. The HOMA-IR was lower in physically active (β: -0.16, 95% CI: -0.26, -0.05) participants versus inactive participants. Participants who had higher WWI and were not physically active (β: 0.69; 95% CI: 0.56, 0.82) had the highest levels of HOMA-IR compared to participants who had lower WWI and were physically active. Subgroup analysis revealed that these correlations were similar in males and females.

CONCLUSION

Our results demonstrated that higher WWI and PA were associated with a lower HOMA-IR and that WWI and PA had a combined association with HOMA-IR. The findings of this study are informative for the preventing insulin resistance in adolescents.

High serum klotho levels are inversely associated with the risk of low muscle mass in middle-aged adults: results from a cross-sectional study

Objective

Muscle mass gradually declines with advancing age, and as an anti-aging protein, klotho may be associated with muscle mass. This study aims to explore the relationship between klotho levels and muscle mass in the middle-aged population.

Methods

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2011 to 2018, we conducted a cross-sectional analysis on a cohort of individuals aged 40-59. Weighted multivariable analysis was employed to assess the correlation between klotho and low muscle mass, with stratified and Restricted Cubic Spline (RCS) analyses.

Results

The cross-sectional investigation revealed a significant negative correlation between klotho levels and the risk of low muscle mass (Model 3: OR = 0.807, 95% CI: 0.712-0.915). A notable interaction between klotho and sex was observed, with a significant interaction effect (P for interaction = 0.01). The risk association was notably higher in females. The risk association was notably higher in females. Additionally, RCS analysis unveiled a significant linear relationship between klotho and low muscle mass (P for nonlinear = 0.9495, P for overall<0.0001).

Conclusion

Our observational analysis revealed a noteworthy inverse relationship between klotho and low muscle mass, particularly prominent among female participants. This discovery provides crucial insights for the development of more effective intervention strategies and offers a new direction for enhancing muscle quality in the middle-aged population.

The association of triglyceride-glucose-waist circumference with metabolic associated fatty liver disease and the severity of liver steatosis and fibrosis in American adults: a population-based study

BACKGROUND

The global obesity pandemic has led to an alarming rise in the prevalence of metabolic-associated fatty liver disease (MAFLD), making it a substantial clinical and economic burden on society. Early detection and effective treatment of MAFLD are imperative to mitigate its impact.

METHODS

This cross-sectional study was conducted involving 4634 adults from the National Health and Nutrition Examination Surveys (NHANES) 2017-2018 cycle. Transient elastography (TE) was used to diagnose MAFLD and assess the extent of liver steatosis and fibrosis. Multivariate logistic regression models were utilized to examine the association between the triglyceride and glucose index-waist circumference (TyG-WC) and the risk of MAFLD, liver fibrosis, and steatosis.

RESULTS

A positive association between TyG-WC and MAFLD persisted across all three models: model1: OR = 8.44, 95% CI: 6.85-10.38 (unadjusted), model2: OR = 8.28, 95% CI: 6.53-10.50 (partially adjusted), and model3: OR = 7.98, 95% CI: 4.11-15.46 (fully adjusted). Further investigation through interaction and stratified analysis revealed that this association was more pronounced in the non-obese and Non-Hispanic White persons groups. Moreover, a non-linear relationship analysis unveiled threshold and saturation effects between TyG-WC and MAFLD. Specifically, a TyG-WC value of approximately 600 may represent the threshold effect for MAFLD risk, while 1200 may signify the saturation effect of MAFLD risk. Finally, a robust correlation between TyG-WC and the severity of liver steatosis and fibrosis was found.

CONCLUSIONS

The findings suggest that the TyG-WC index exhibits excellent predictive value for MAFLD in the general American population.

The association between appendicular skeletal muscle index and bone mineral density in children and adolescents with chronic kidney disease: A cross-sectional study

Chronic kidney disease (CKD), a pervasive public health concern, can lead to complications like sarcopenia and reduced bone mineral density (BMD). However, it is still unclear exactly how muscle mass correlates with BMD in youngsters and adolescents with CKD. We aimed to investigate the association between appendicular skeletal muscle index (ASMI) and BMD among children and adolescents with CKD. In our research, we utilized data from the National Health and Nutrition Examination Survey (NHANES) collected between 2011 and 2014 to investigate the association of ASMI with BMD among this population. The association linking ASMI with total BMD was examined through multivariate linear regression models. Furthermore, fitted smoothing curves were employed, as well as generalized additive models. Our analysis finally included 503 CKD participants aged between 8 and 19 years. We found a significant association linking ASMI with total BMD among children and adolescents with CKD. The connection persisted even after accounting for covariates. Upon subgroup analysis, there was a statistically significant association of ASMI with total BMD for both males and females, as well as for Mexican-American and non-Hispanic White populations. However, no significant association was observed in other Hispanic, non-Hispanic Black, or populations of other races. We discovered a positive correlation linking the ASMI and the total BMD in children and teenagers with CKD. In CKD patients, maintaining skeletal muscle mass may be crucial for managing and preventing renal osteodystrophy.

Relationship between immune nutrition index and all-cause and cause-specific mortality in U.S. adults with chronic kidney disease

Objective

The available evidence regarding the association of immune nutrition status with chronic kidney disease (CKD) is limited. Thus, the present study examined whether immunonutrition indices were associated with renal function and mortality among CKD individuals.

Research design and methods

This study enrolled 6,099 U.S. adults with CKD from the NHANES 2005-2018 database. Participants were matched with National Death Index records until 31 December 2019 to determine mortality outcomes. The time-dependent receiver operating characteristic was utilized to identify the most effective index among the prognostic nutritional index (PNI), system inflammation score (SIS), Naples prognostic score (NPS), and controlling nutritional status (CONUT) for predicting mortality. Cox regression models were employed to evaluate the associations of immunonutrition indices with mortality in participants with CKD.

Results

The PNI exhibited the strongest predictive power among the four indices evaluated and the restricted cubic spline analysis revealed a cutoff value of 51 for the PNI in predicting mortality. During a median follow-up of 72 months (39-115 months), a total of 1,762 (weighted 24.26%) CKD participants died from all causes. The Kaplan-Meier curve demonstrated a reduced risk of death for the subjects with a higher PNI compared to those in the lower group. Besides, after adjusting for multiple potential confounders, a higher PNI remained an independent predictor for lower risks of all-cause mortality (HR 0.80, 95%CI: 0.71-0.91, p < 0.001) and cardiovascular disease (CVD) mortality (HR 0.69, 95%CI: 0.55-0.88, p = 0.002) in individuals with CKD.

Conclusion

In CKD, a higher PNI level was significantly associated with lower mortality from all causes and CVD. Thus, the clinical utility of this immunonutrition indicator may facilitate risk stratification and prevent premature death among patients with CKD.

Serum-Creatinine-to-Cystatin C-to-Waist-Circumference Ratios as an Indicator of Severe Airflow Limitation in Older Adults

BACKGROUND

This study aimed to investigate the association between the serum-creatinine-to-cystatin C-to-waist-circumference (CCR/WC) ratio with lung function and severe airflow limitation (SAL).

METHODS

The data were derived from the China Health and Retirement Longitudinal Study. Peak expiratory flow (PEF) was used as a measure of lung function parameter. Logistic and linear regression were utilized separately to evaluate the relationship between the CCR/WC ratio with PEF and SAL in baseline. Restricted cubic spline was used to explore potential non-linear associations between the CCR/WC ratio and SAL. Cox proportional-hazards models were used to assess the association between CCR/WC quartiles and the risk of new-onset SAL.

RESULTS

A total of 6105 participants were included. This study revealed a positive association between the CCR/WC ratio and lung function (PEF: β [partial coefficient]: 25.95, 95%CI: 12.72 to 39.18, p < 0.001; PEF/PEF prediction: β = 0.08, 95%CI: 0.05 to 0.12, p < 0.001) and an inverse association relationship with SAL (OR [odds ratio]: 0.64, 95% confidence interval [CI]: 0.47 to 0.85, p = 0.003). Subgroup analysis showed a significant association between the CCR/WC ratio and SAL in males (OR: 0.58, 95% CI: 0.37 to 0.90, p = 0.017) but not in females (p = 0.059). Cox regression analysis revealed a decreased risk of SAL in the quartiles (Q2-4) compared to the first quartile of the CCR/WC ratio (hazard ratios [HRs]: 0.49 to 0.73, all p < 0.05).

CONCLUSIONS

This study highlights a positive association between the CCR/WC ratio and lung function, with a potential protective effect against SAL.

Dose-response relationship between dietary antioxidant intake and diabetic kidney disease in the US adults with diabetes

AIM

The effects of dietary antioxidants on numerous diseases have been widely studied. However, the evidence regarding composite dietary antioxidant index (CDAI) and diabetic kidney disease (DKD) in individuals with diabetes is scarce. This study aimed to investigate the associations of CDAI with DKD and mortality in adults with diabetes mellitus (DM).

METHODS

This study utilized data from 5676 adult DM participants from the National Health and Nutrition Examination Survey (NHANES) of 2007-2018. The study followed up on death outcomes by linking the data to records from the National Death Index until December 31, 2019. CDAI was evaluated using a well-established method that included six food-sourced antioxidants derived from 24-h dietary recall: selenium, zinc, vitamin A, vitamin C, vitamin E and carotenoids. The regression models were used to estimate the relationships of CDAI with DKD and mortality in diabetic individuals.

RESULTS

The weighted mean CDAI level for the 5676 participants, which represented 31.36 million noninstitutionalized residents of the US, was 0.33. Based on CDAI quartiles, participants were classified into four groups. CDAI levels were significantly associated with age, gender, race, physical activity, estimated glomerular filtration rate and the prevalence of albuminuria, DKD and hyperuricemia. DKD occurred in 36.44% of diabetic participants, and higher CDAI levels were independently associated with a lower risk of DKD (OR 0.74, 95%CI 0.59-0.94, p for trend = 0.004) in diabetic individuals after multivariate adjustment. During a median follow-up of 67 months (38-104 months), a total of 1065 (15.80%) diabetic individuals died from all causes. Diabetic individuals with higher CDAI levels (Q4) demonstrated a lower risk of all-cause mortality (HR 0.67, 95% CI: 0.52-0.86, p for trend = 0.01) after adjusting for age, gender and race.

CONCLUSIONS

Maintaining an adequate antioxidant diet, as reflected in higher CDAI levels, may lower the risk of DKD and mortality in diabetic individuals. These findings offer a promising approach to managing diabetes and highlight the potential of food-based antioxidants as a preventative measure. Further research is warranted to explore the underlying mechanism linking dietary antioxidants and DKD and mortality in diabetic individuals.

Association between physical activity and bone mineral density in postmenopausal women: a cross-sectional study from the NHANES 2007-2018

BACKGROUND

Physical activity (PA) is generally encouraged for the treatment of osteoporosis. However, epidemiological statistics on the level of physical activity required for bone health are scarce. The purpose of this research was to analyze the association between PA and total spine bone mineral density (BMD) in postmenopausal women.

METHODS

The research study included postmenopausal women aged ≥ 50 from the National Health and Nutrition Examination Survey. The metabolic equivalent (MET), weekly frequency, and duration of each activity were used to calculate PA. Furthermore, the correlations between BMD and PA were investigated by multivariable weighted logistic regression.

RESULTS

Eventually, 1681 postmenopausal women were included, with a weighted mean age of 62.27 ± 8.18 years. This study found that performing ≥ 38MET-h/wk was linked to a lower risk of osteoporosis after controlling for several covariates. Furthermore, the subgroup analysis revealed that the connection between total spine BMD and moderate-to-vigorous PA was more obvious among postmenopausal women aged < 65 years or individuals with normal BMI (< 25 kg/m²).

CONCLUSION

Physical activity ranging from moderate to vigorous was linked to higher total spine BMD in postmenopausal women.

Association of serum uric acid-to-high-density lipoprotein cholesterol ratio with non-alcoholic fatty liver disease in American adults: a population-based analysis

Objective

Non-invasive disease indicators are currently limited and need further research due to the increased non-alcoholic fatty liver disease (NAFLD) prevalence worldwide. The serum uric acid-to-high-density lipoprotein cholesterol ratio (UHR) has been recognized as a novel inflammatory and metabolic marker. Herein, we explored the correlation between UHR and the risk of NAFLD in-depth.

Methods

A total of 3,766 participants were included in our survey, and the National Health and Nutrition Examination Survey (NHANES) 2017-2018 cycle provided the cross-sectional study population. Weighted multivariable logistic regression and multivariate linear regression analyses were performed to assess the association between the UHR and the odds of NAFLD and liver steatosis and fibrosis severity, respectively. Moreover, we explored the non-linear relationship between the UHR and NAFLD by the generalized additive model.

Results

NAFLD probabilities were statistically demonstrated to be positively correlated with the UHR (OR = 1.331 per SD increase, 95% CI: 1.100, 1.611). The positive connection of the UHR with NAFLD risk persisted significantly in female subjects but not in male subjects in subgroup analyses stratified by gender. The non-linear relationship analysis demonstrated that a UHR between ~20 and 30% suggested a saturation effect of NAFLD risk. Furthermore, a dramatically positive correlation was found between the UHR and hepatic steatosis severity but not fibrosis. Finally, the receiver operating characteristic analysis suggested that UHR had a better predictive value for NAFLD than either serum uric acid (sUA) or high-density lipoprotein cholesterol (HDL) alone [UHR (area under curve): 0.6910; 95% CI: 0.6737-0.7083; P < 0.0001].

Conclusion

Our investigation revealed that the elevated UHR level was independently related to an increased NAFLD risk and the severity of liver steatosis in American individuals. The correlation differed according to sex. This non-invasive indicator may enhance the capacity to predict the onset of NAFLD and may uncover alternative therapeutic interventional targets.

Physical Activity Maintain Immune Response Through TLR-2/TLR-4 Gene Expression in Type-2 Diabetes Mellitus Patient at Medan City

Background

The Increasing in type-2 diabetes mellitus (T2DM) needs to solve comprehensively and holistically. Patients with T2DM should have self-coping due to lifestyle modification. Abdominal fat accumulation can release pro-inflammatory cytokine that leads TLR-2 and TLR-4 to the response. These two kinds of toll-like receptors exist on the monocyte surface membrane which is an innate immunity cell.

Objective

The aims of this study were to get the profile of physical activity, metabolic state, and mononuclear cell response to the expression of the TLR2 and TLR4 genes in T2DM patients.

Methods

It was a descriptive-analytic study with a cross-sectional study design. Thirty-two eligible patients with inclusion criteria participated as subjects. All subjects answered questions by IPAQ, and checked metabolic state with body composition analysis. The TLR2 and TLR4 gene expression was determined with quantitative Real- Time PCR.

Results

This study result found that most T2DM patients were in a highly active category in which most of their activity was walking (light intensity). The average abdominal circumferences were 91.81 ± 15.4 cm, body fat percentage was 29.5 ± 8.8%, and fasting blood sugar was 187.07 ± 67.03 mg/dl. Mononuclear cells number were normal. The expression of the TLR2 gene was lower by 0.71 fold and TLR4 gene expression was lower by 0.9 fold compared with non-DM (p<0.05). By chi-square test, there was a positive correlation between TLR2 gene expression with fasting blood glucose (p=0.011, and a positive correlation between the abdominal circumference and TLR4 gene expression (p=0.011).

Conclusion

Type-2 Diabetes mellitus patients in primary health care keep walking as their physical activity to maintain blood glucose. Patients need to do moderate to vigorous exercise regularly to reduce body fat percentage especially abdominal fat to reduce Toll-like receptor gene expression, so insulin resistance and blood glucose level might decline to normal.

Early-Adulthood Weight Change and Later Physical Activity in Relation to Cardiovascular and All-Cause Mortality: NHANES 1999-2014

Limited evidence investigated the combined influence of early-adulthood weight change and later physical activity on the risk of cardiovascular (CVD) and all-cause mortality. The aim of this study is to explore the associations of early-adulthood weight change and later physical activity with CVD and all-cause mortality. This is a cohort study of 23,193 US adults aged 40 to 85 years from the National Health and Nutrition Examination Survey (NHANES) 1999 to 2014. Cox proportional hazards regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) of CVD and all-cause mortality associated with early-adulthood weight change and later physical activity. During a median follow-up of 9.2 years, there were 533 and 2734 cases of CVD and all-cause deaths. Compared with being physically inactive, the HRs of the CVD mortality of being physically active were 0.44 (0.26 to 0.73), 0.58 (0.19 to 1.82), 0.38 (0.17 to 0.86) and 0.46 (0.21 to 1.02) among individuals with stable normal, stable obese, non-obese to obese and maximum overweight early-adulthood weight change patterns. Using stable normal patterns that were physically active later as the reference, other early-adulthood weight change patterns did not show a significantly higher risk of CVD mortality when participants were physically active in later life; later physically inactive participants had a significantly increased risk of CVD mortality, with HRs of 2.17 (1.30 to 3.63), 5.32 (2.51 to 11.28), 2.59 (1.29 to 5.18) and 2.63 (1.32 to 5.26) in the stable normal, stable obese, non-obese to obese and maximum overweight groups, respectively. Similar results can be seen in the analyses for all-cause mortality. Our findings suggest that inadequate physical activity worsens the negative impact of unhealthy early-adulthood weight change patterns, which is worthy of being noted in the improvement of public health.

The Effect of Low Glycemic Index Mediterranean Diet and Combined Exercise Program on Metabolic-Associated Fatty Liver Disease: A Joint Modeling Approach

Background: Excessive caloric intake and reduced energy expenditure are associated with the onset of metabolic-associated fatty liver disease (MAFLD). The aim of this study was to probe the benefits of a low glycemic index Mediterranean diet (LGIMD) and a combined exercise program (CEP) on MAFLD by monitoring the clinical process through anthropometric measurement, body mass index (BMI), and specific biomarkers, such as the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Methods: The study was conducted at the National Institute of Gastroenterology, ‘S. de Bellis’, Italy. Subjects were invited to join the study for 12 months. Results: 54 participants were enrolled. Joint modeling of longitudinal and time-to-event data was applied. Overall, a statistically significant direct effect of LGIMD/CEP adherence on ln (BMI), a statistically significant direct effect of LGIMD/CEP adherence on time-to-event and a strong statistically significant direct effect of log (BMI) on time-to-event were observed. In addition, a statistically significant direct effect of LGIMD/CEP adherence on ln(HOMA-IR), a statistically significant direct effect of LGIMD/CEP adherence on time-to-event and a statistically significant direct effect of ln(HOMA-IR) on time-to-event were observed. Conclusions: LGIMD/CEP significantly improved MAFLD status; in addition, longitudinal BMI and HOMA-IR were good predictors of the disappearance of diagnostic criteria for MAFLD.

Development and Validation of an Insulin Resistance Model for a Population with Chronic Kidney Disease Using a Machine Learning Approach

Background: Chronic kidney disease (CKD) is a complex syndrome without a definitive treatment. For these patients, insulin resistance (IR) is associated with worse renal and patient outcomes. Until now, no predictive model using machine learning (ML) has been reported on IR in CKD patients. Methods: The CKD population studied was based on results from the National Health and Nutrition Examination Survey (NHANES) of the USA from 1999 to 2012. The homeostasis model assessment of IR (HOMA-IR) was used to assess insulin resistance. We began the model building process via the ML algorithm (random forest (RF), eXtreme Gradient Boosting (XGboost), logistic regression algorithms, and deep neural learning (DNN)). We compared different receiver operating characteristic (ROC) curves from different algorithms. Finally, we used SHAP values (SHapley Additive exPlanations) to explain how the different ML models worked. Results: In this study population, 71,916 participants were enrolled. Finally, we analyzed 1,229 of these participants. Their data were segregated into the IR group (HOMA IR > 3, n = 572) or non-IR group (HOMR IR ≤ 3, n = 657). In the validation group, RF had a higher accuracy (0.77), specificity (0.81), PPV (0.77), and NPV (0.77). In the test group, XGboost had a higher AUC of ROC (0.78). In addition, XGBoost also had a higher accuracy (0.7) and NPV (0.71). RF had a higher accuracy (0.7), specificity (0.78), and PPV (0.7). In the RF algorithm, the body mass index had a much larger impact on IR (0.1654), followed by triglyceride (0.0117), the daily calorie intake (0.0602), blood HDL value (0.0587), and age (0.0446). As for the SHAP value, in the RF algorithm, almost all features were well separated to show a positive or negative association with IR. Conclusion: This was the first study using ML to predict IR in patients with CKD. Our results showed that the RF algorithm had the best AUC of ROC and the best SHAP value differentiation. This was also the first study that included both macronutrients and micronutrients. We concluded that ML algorithms, particularly RF, can help determine risk factors and predict IR in patients with CKD.

Serum, Dietary, and Supplemental Vitamin D Levels and Insulin Resistance in 6294 Randomly Selected, Non-Diabetic U.S. Adults

The primary aim of this study was to determine the associations between serum, dietary, and supplemental vitamin D levels and insulin resistance in 6294 non-diabetic U.S. adults. A total of 8 years of data from the 2011−2018 National Health and Nutrition Examination Survey (NHANES) and a cross-sectional design were utilized to answer the research questions. Serum vitamin D levels were quantified using high-performance liquid chromatography−tandem mass spectrometry. Dietary and supplemental vitamin D intakes were assessed using the average of two 24 h dietary recalls taken 3−10 days apart. The homeostatic model assessment (HOMA), based on fasting glucose and fasting insulin levels, was employed to index insulin resistance. Demographic covariates were age, sex, race, and year of assessment. Differences in physical activity, body mass index (BMI), cigarette smoking, body weight, season, and energy intake were also controlled statistically. Serum levels of vitamin D differed significantly, and in a dose−response order, across quartiles of HOMA-IR, after adjusting for year, age, sex, and race (F = 30.3, p < 0.0001) and with all the covariates controlled (F = 5.4, p = 0.0029). Dietary vitamin D levels differed similarly across HOMA-IR quartiles, but to a lesser extent, respectively (F = 8.1, p = 0.0001; F = 2.9, p = 0.0437). Likewise, supplemental vitamin D levels also differed across the HOMA-IR quartiles, respectively (F = 3.5, p = 0.0205; F = 3.3, p = 0.0272). With all the covariates controlled, the odds of having insulin resistance were significantly greater for those in the lowest quartile of serum and supplemental vitamin D intake compared to the other quartiles combined. In conclusion, in this nationally representative sample, serum, dietary, and supplemental vitamin D were each predictive of insulin resistance, especially in those with low serum levels and those with no supplemental intake of vitamin D.

Association between physical activity and insulin resistance using the homeostatic model assessment for insulin resistance independent of waist circumference

Only a few studies have evaluated the relationship between physical activity (PA) and Homeostatic model assessment for insulin resistance (HOMA-IR). Therefore, we aimed to analyze the association between HOMA-IR and PA. We included 280,194 Korean without diabetes who underwent health examinations. The short form of the International Physical Activity Questionnaire was completed. PA level was divided into sedentary, mild PA, and health-enhancing PA (HEPA). The HOMA-IR levels were calculated. Confounding factors including waist circumference were adjusted. The median follow-up duration was 4.13 years. A significant inverse relationship was observed between PA level and HOMA-IR (p < 0.001). Compared with the sedentary group, HOMA-IR was lower in the HEPA group (p < 0.001), even when HEPA group decreased PA level over time (p < 0.001). Mild PA (p < 0.001) or HEPA showed a lower risk of HOMA-IR progression (p < 0.001). Increasing PA or maintaining HEPA was significantly associated with a lower HOMA-IR (p < 0.001), HOMA-IR improvement (p < 0.001), and a lower risk of HOMA-IR progression (p < 0.001). Our findings support the inverse relationship between PA and HOMA-IR in a population without diabetes. PA might improve IR and prevent its progression among populations without diabetes, independent of the waist circumference.

Macronutrient Intake and Insulin Resistance in 5665 Randomly Selected, Non-Diabetic U.S. Adults

The main goal of this investigation was to evaluate the relationships between several macronutrients and insulin resistance in 5665 non-diabetic U.S. adults. A secondary objective was to determine the extent to which the associations were influenced by multiple potential confounding variables. A cross-sectional design and 8 years of data from the 2011–2018 National Health and Nutrition Examination Survey (NHANES) were used to answer the research questions. Ten macronutrients were evaluated: total carbohydrate, starch, simple carbohydrate, dietary fiber, total protein, total fat, saturated, polyunsaturated, monounsaturated, and total unsaturated fat. The homeostatic model assessment (HOMA), based on fasting glucose and fasting insulin levels, was used to index insulin resistance. Age, sex, race, year of assessment, physical activity, cigarette smoking, alcohol use, and waist circumference were used as covariates. The relationships between total carbohydrate intake (F = 6.7, p = 0.0121), simple carbohydrate (F = 4.7, p = 0.0344) and HOMA-IR were linear and direct. The associations between fiber intake (F = 9.1, p = 0.0037), total protein (F = 4.4, p = 0.0393), total fat (F = 5.5, p = 0.0225), monounsaturated fat (F = 5.5, p = 0.0224), and total unsaturated fat (F = 6.5, p = 0.0132) were linear and inversely related to HOMA-IR, with 62 degrees of freedom. Starch, polyunsaturated fat, and saturated fat intakes were not related to HOMA-IR. In conclusion, in this nationally representative sample, several macronutrients were significant predictors of insulin resistance in U.S. adults.