The Association between the Dietary Inflammatory Index and Thyroid Function in U.S. Adult Males

Relationship between vitamin B6 intake and thyroid function in US adults: NHANES 2007-2012 results

BACKGROUND

Existing studies have focused on the relationship between vitamin B6 and thyroid disease. However, there is a lack of large cross-sectional studies reporting on the relationship between vitamin B6 and thyroid function. Therefore, the present study aimed to assess the association between vitamin B6 intake and thyroid function in a population of US adults aged 20 years and older, using data from the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2012.

METHODS

Demographic, dietary, thyroid function, and relevant data from NHANES 2007-2012 were collected. The relationship between vitamin B6 intake and thyroid function was analysed using weighted multiple regression and restricted cubic spline analysis, including subgroup and interaction analysis.

RESULTS

The study included 6954 participants with a weighted mean age of 47.39  ± 16.60 years, mean vitamin B6 intake of 2.07 ± 1.15 mg, and mean TT4 level of 7.88 ± 1.61 μg/dL. A statistically significant negative correlation was noted between vitamin B6 intake and TT4 levels (β  =  -0.05, 95% CI  =  -0.10 to 0.00, P  =  0.033). In addition to this, subgroup analyses we found: In the gender subgroup, a significant negative correlation was found between vitamin B6 intake and TT4 levels in the male population (β = -0.06, 95% CI  =  -0.11 to -0.01, P  =  0.028); in the age subgroup, a significant negative correlation was found between vitamin B6 intake and TT4 levels in older people aged 60-80 years (β  =  -0. 13, 95% CI  =  -0.23 to -0.04, P  =  0.008); in the BMI subgroup, we found a significant negative correlation between vitamin B6 intake and TT4 levels in overweight people (BMI: 25-29.9 kg/m2) (β  =  -0.13, 95% CI  =  -0.20 to -0.06, P < 0. 001); in the iodine content subgroup, we found a significant negative correlation between vitamin B6 intake and TT4 levels in people with a normal iodine intake (100-299 ug/L) (β  =  -0.07, 95% CI  =  -0.13 to -0.01, P  =  0.021). Finally, in the subgroups of gender, age, BMI, and iodine content, no interaction was found.

CONCLUSIONS

To summarise, we believe that vitamin B6 may reduce serum TT4 levels by inhibiting inflammation.

The association between dietary inflammatory index and bone health in US adolescents: Analysis of the NHANES data

Introduction

Adolescents with a lower peak bone mineral density (BMD) and bone mineral content (BMC) have an elevated risk of osteoporosis in adulthood. The impact of diet on bone health, particularly its role in managing inflammation, which is a key factor in bone health, is gaining wider recognition. Despite evidence that anti-inflammatory diets can enhance bone health, the link between the dietary inflammatory index (DII) and bone health among US adolescents has not been thoroughly investigated. This study aimed to evaluate the correlation between DII score and bone health in this population.

Methods

This cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES) of US adolescents aged 12-18 years, spanning surveys from 2001 to 2018. The DII was derived from dietary recall data obtained through questionnaire interviews. Bone health was assessed through total body less head (TBLH) BMD and BMC z-scores and lumbar spine bone mineral apparent density for age (BMADa).

Results

The study comprised 8773 adolescents with a mean age of 14.94 ± 1.97 years, 52.2 % were male. Multivariate linear regression analysis revealed a negative correlation between DII and lumbar spine BMADa (β = -0.000003, 95 % confidence interval [CI], -0.000005 to -0.000001; P = 0.001).This significant association remained robust when DII was treated as a categorical variable. Compared with individuals in quartile 1(Q1) DII scores (-3.71 to 1.04), those in Q4 (3.37 to 5.04) had lower BMADa, with a regression coefficient of -0.00002 (95 % CI, -0.00003 to -0.000007, P < 0.001). DII was negatively correlated with TBLH BMC z-scores; however, the difference was not statistically significant. Subgroup analyses showed that DII was associated with lumbar spine BMADa and TBLH BMC z-scores in participants who were male, non-black, with a higher educational level, with a high family income, and underweight to normal weight. We found no significant association between DII and TBLH BMD z-scores.

Conclusion

The findings from this cross-sectional analysis indicate a significant association between the DII and bone health among adolescents in the US, with a notable impact in males and non-black. These insights underscore the importance of adopting dietary patterns to mitigate inflammation and to support optimal bone health and metabolism.

Association between oxidative balance score and thyroid function and all-cause mortality in euthyroid adults

Abnormal fluctuations in thyroid function within the reference range were strongly associated with increased all-cause mortality. This study aimed to analyze the association between oxidative balance score (OBS) and free thyroxine (FT4) and thyrotropin (TSH) in euthyroid adults, as well as their interrelationships with mortality. 5727 euthyroid adults were selected from the National Health and Nutrition Examination Survey (NHANES). Weighted linear regression investigated the potential association of OBS with FT4 and TSH. In addition, COX proportional hazard models and restricted cubic spline (RCS) were used to investigate the association between OBS, FT4, TSH, and all-cause mortality. The results showed that OBS was negatively associated with serum FT4 concentrations in euthyroid adults (- 2.95%, 95% CI - 5.16%, - 0.92%). Additionally, the all-cause mortality rate was significantly higher in the fourth quartile (Q4) of FT4 compared to the first quartile (Q1) (HR 1.40, 95% CI 1.07-1.85). In the fourth quartile of OBS, the all-cause mortality rate was 31% lower than in Q1 (HR 0.69, 95% CI 0.52-0.92). Mediation analyses indicated that FT4 partially mediated the relationship between OBS and all-cause mortality. These results suggest a significant negative association between OBS and serum FT4, while both OBS and FT4 are strongly associated with mortality. However, the effect of OBS on serum FT4 is relatively limited, and therefore its clinical significance needs to be interpreted objectively.

Associations between surrogate insulin resistance indexes and osteoarthritis: NHANES 2003-2016

Insulin resistance (IR) and abdominal obesity are key in osteoarthritis (OA) development. The triglyceride glucose (TyG) index, along with indicators such as the visceral adiposity index (VAI), and lipid accumulation product (LAP), are increasingly used to measure IR. This study aims to explore the associations between surrogate IR indexes and OA, assessing their diagnostic efficacy within American populations. This study included 14,715 adults from the National Health and Nutrition Examination Survey 2003-2016. Logistic regression models and restricted cubic spline were used to explore the relationship between surrogate IR indexes and OA. Receiver operating characteristic curves were constructed to assess the diagnostic efficacy of these indices, with the area under the curve (AUC) as the metric. TyG, glucose triglyceride-waist circumference (TyG-WC), glucose triglyceride-body mass index (TyG-BMI), glucose triglyceride-waist height ratio (TyG-WHtR), VAI and LAP were significantly and positively associated with the prevalence of OA (all p < 0.01). After adjusting for various potential confounders, TyG-WC, TyG-BMI, TyG-WHtR and LAP remained significantly correlated with the prevalence of OA. Furthermore, restricted cubic spline revealed a nonlinear association between TyG-BMI, TyG-WHtR and LAP (all P-non-linear < 0.05). Receiver operating characteristic curves indicated that TyG-WHtR (AUC 0.633) demonstrated more robust diagnostic efficacy. Additionally, the sensitivity analysis produced results consistent with the primary findings. TyG and its combination with obesity indicators and LAP, are positively associated with the prevalence of OA, with TyG-WHtR showing the highest diagnostic efficacy.

Investigating the impact of dioxins, furans, and coplanar polychlorinated biphenyls on mortality, inflammatory states, and chronic diseases: An integrative epidemiological analysis

Several organic pollutants, including dioxins, furans, and coplanar polychlorinated biphenyls (PCBs), have become a growing concern due to their significant capacity for accumulation and migration across regions, as well as their extended half-lives and relatively high toxicity. Our study aimed to assess the impact of these pollutants on mortality, inflammatory states, and chronic diseases. Exposure was quantified in serum through high-resolution gas chromatography and isotope-dilution high-resolution mass spectrometry. Statistical analyses employed multivariate Cox regression, multivariate logistic regression, restricted cubic splines and subgroup analysis. The results indicated a significant increase in mortality (p < 0.05) associated with the seven substances classified as dioxins, furans, and PCBs. Moreover, these pollutants were linked to a higher incidence of chronic diseases, including hematological disorders, chronic kidney disease, hypertension, and diabetes (p < 0.05). Additionally, a robust correlation was observed between serum C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLR) concentrations and these substances, revealing their proinflammatory effects at specific concentrations. Consequently, our research unmasked that exposure to dioxins, furans, and coplanar PCBs could be associated with an elevated mortality rate, increased inflammatory conditions, and a higher incidence of chronic diseases. We proposed that exposure to these pollutants may initiate various afflictions by activating the inflammatory system, ultimately resulting in increased mortality. However, this hypothesis requires further empirical investigation to validate its assertions.

Association between sensitivity to thyroid hormones and trabecular bone score in euthyroid individuals: a population-based cross-sectional study

BACKGROUND

Thyroid hormone is a known pivotal factor that affects bone metabolism; however, whether bone microarchitecture is associated with thyroid hormone sensitivity is poorly understood. The trabecular bone score (TBS) serves as an essential indicator for assessing bone microarchitecture. This study aimed to investigate the relationship between sensitivity to thyroid hormones and TBS in euthyroid individuals.

METHODS

This cross-sectional study involved 3320 euthyroid participants from the National Health and Nutrition Examination Survey (NHANES) 2007-2008. Data, including thyroid function, TBS and other related parameters, were extracted and analyzed. The indices of thyroid hormone sensitivity, including the thyrotropin thyroxine resistance index (TT4RI), thyroid-stimulating hormone index (TSHI), thyroid feedback quantile-based index (TFQI) and parametric thyroid feedback quantile-based index (PTFQI), were calculated. Greater values of these indicators indicated a greater degree of impaired thyroid hormone sensitivity.

RESULTS

Impaired sensitivity to thyroid hormones was associated with degraded bone microarchitecture following adjustments for confounding variables (TT4RI: P = 0.005, TSHI: P = 0.008, TFQI: P = 0.003 and PTFQI: P = 0.006). The restricted cubic spline model demonstrated a positive relationship between TT4RI, TSHI, TFQI, PTFQI and degraded bone microarchitecture. Similar findings were observed in the analysis of subgroups stratified by age, sex, race, diabetes status, hypertension status and hyperuricemia status.

CONCLUSIONS

In euthyroid individuals, impaired sensitivity to thyroid hormones is associated with degraded bone microarchitecture. However, further studies are required to confirm this relationship.

Association between thyroid hormones and cognitive functioning in euthyroid elderly adults: a cross-sectional preliminary study from the NHANES 2011-2012 survey

Objective

Changes in serum thyroid hormone levels may affect cognitive functioning in euthyroid individuals. This study used representative data from the National Health and Nutrition Examination Survey (NHANES) to comprehensively examine the association of thyroid hormones with different tests of cognitive functioning among US elderly people aged ≥60 years.

Methods

This study was a cross-sectional preliminary study with a total of 734 participants from the NHANES 2011-2012 survey. Thyroid function was measured using competitive binding immune-enzymatic assays, while cognitive functioning was measured using a series of assessments, including the Consortium to Establish a Registry for Alzheimer's Disease-Word Learning (CERAD W-L), Animal Fluency Test, and Digit Symbol Substitution Test (DSST). Weighted multiple linear regression models and binary logistic regression analyses were used to examine the association between thyroid hormone levels and cognitive functioning. All statistical analyses were performed using SPSS version 20.0, and R software.

Results

Weighted multivariable linear regression showed that FT3 was negatively associated with the Animal Fluency Test and DSST (β=-0.113, 95% CI: -3.279, -0.803, P=0.001; β=-0.062, 95% CI: -6.565, -0.470, P=0.024, respectively) after adjustment for potential covariates. subgroup analysis stratified by sex revealed a negative association between FT3 levels and the Animal Fluency Test in men (β=-0.163, 95% CI: -4.643, -1.153, P=0.001). For female participants, FT3 was negatively associated with not only the Animal Fluency Test but also DSST (β=-0.099, 95% CI: -3.543, -0.093, P=0.039; β=-0.093, 95% CI: -10.288, -1.326, P=0.011). Binary logistic regression showed that the significantly increased adjusted odds ratios (aORs) (95% CI) between the risk of impaired cognitive functioning and FT3 across Q3 and Q4 compared with Q1 were 2.025 (1.092, 3.753) and 2.365 (1.261, 4.433), respectively, for DSST in overall participants. Furthermore, there were significant differences between participants with and without impaired cognitive functioning for serum FT3 levels in overall participants based on DSST score (P=0.020).

Conclusions

There was a significant inverse relationship between FT3 levels within the normal range and cognitive functioning after adjusting for potential covariates. Future longitudinal cohort studies should be conducted to determine the causal relationship between thyroid hormone levels and cognitive functioning.

Association between vitamin C intake and thyroid function among U.S. adults: a population-based study

Background

Although some evidence suggests a role for vitamin C intake in thyroid diseases, the complex interplay between vitamin C intake and thyroid function remains incompletely understood. The objective of this study was to explore the relationship between vitamin C intake and serum thyroid function in the United States adults.

Methods

A total of 5,878 participants from the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2012 were included in this study. Weighted multivariate linear regression models, subgroup analyses, and interaction terms were used to assess the association between vitamin C intake, evaluated as a continuous and categorical variable, and thyroid function. Additionally, restricted cubic spline (RCS) regression was employed to assess any nonlinear relationship that may exist between vitamin C intake and thyroid function.

Results

After adjusting for covariates, our research found a significant inverse correlation between vitamin C intake and total thyroxine (TT4) (β= -0.182, P= 0.006). Using subgroup analyses, the association was more pronounced among subjects with lower alcohol consumption(β= -0.151, P=0.013, P for interaction = 0.043). In RCS regression, the correlation between vitamin C and TT4 exhibited a distinct reversed L-shaped curve pattern in total participants (P for nonlinear = 0.005) and male adults (P for nonlinear = 0.014). Additionally, we found an inverted U-shaped curve pattern in the relationship between vitamin C intake and FT4 (P for nonlinear = 0.029), while an U-shaped curve relationship was observed between vitamin C consumption and the FT3/FT4 ratio (P for nonlinear = 0.026).

Conclusion

The findings of our study have illustrated a notable correlation between vitamin C intake and thyroid function. A high level of vitamin C intake is associated with a decreased in TT4 levels among American adults, and the association was more pronounced among subjects with lower alcohol consumption. Furthermore, our analysis revealed a nonlinear correlation between the intake of vitamin C and the levels of TT4, FT4, and FT3/FT4 ratio. Our findings support the rationale for making food-based dietary recommendations and maybe provide guidance for diet guidelines with thyroid dysfunction to a certain extent in the future.

Translational Algorithms for Technological Dietary Quality Assessment Integrating Nutrimetabolic Data with Machine Learning Methods

Recent advances in machine learning technologies and omics methodologies are revolutionizing dietary assessment by integrating phenotypical, clinical, and metabolic biomarkers, which are crucial for personalized precision nutrition. This investigation aims to evaluate the feasibility and efficacy of artificial intelligence tools, particularly machine learning (ML) methods, in analyzing these biomarkers to characterize food and nutrient intake and to predict dietary patterns.

METHODS

We analyzed data from 138 subjects from the European Dietary Deal project through comprehensive examinations, lifestyle questionnaires, and fasting blood samples. Clustering was based on 72 h dietary recall, considering sex, age, and BMI. Exploratory factor analysis (EFA) assigned nomenclature to clusters based on food consumption patterns and nutritional indices from food frequency questionnaires. Elastic net regression identified biomarkers linked to these patterns, helping construct algorithms.

RESULTS

Clustering and EFA identified two dietary patterns linked to biochemical markers, distinguishing pro-Mediterranean (pro-MP) and pro-Western (pro-WP) patterns. Analysis revealed differences between pro-MP and pro-WP clusters, such as vegetables, pulses, cereals, drinks, meats, dairy, fish, and sweets. Markers related to lipid metabolism, liver function, blood coagulation, and metabolic factors were pivotal in discriminating clusters. Three computational algorithms were created to predict the probabilities of being classified into the pro-WP pattern. The first is the main algorithm, followed by a supervised algorithm, which is a simplified version of the main model that focuses on clinically feasible biochemical parameters and practical scientific criteria, demonstrating good predictive capabilities (ROC curve = 0.91, precision-recall curve = 0.80). Lastly, a reduced biochemical-based algorithm is presented, derived from the supervised algorithm.

CONCLUSIONS

This study highlights the potential of biochemical markers in predicting nutritional patterns and the development of algorithms for classifying dietary clusters, advancing dietary intake assessment technologies.

The association between lipid accumulation products and depression in U.S. adults: A cross-sectional study from NHANES 2005-2018

OBJECTIVE

The purpose of this study was to investigate the correlation between lipid accumulation products (LAP) and depression among adults in the United States.

METHODS

We analyzed data from 13,051 persons participating in the NHANES 2005-2018 cycle. The LAP index was calculated using the waist circumference (WC) and serum triglyceride (TG) levels, which reflect lipid toxicity. Participants who scored ≥10 on the Patient Health Questionnaire-9 (PHQ-9) were considered depressed. Multivariate logistic regression analyses were conducted to explore the association between the LAP index and depression. Subgroup analysis was also conducted to identify sensitive populations. Smoothed curve fitting and generalized additive model (GAM) regression were performed to verify the association between the LAP index and depression.

RESULTS

After adjusting for all potential confounders, the risk of depression increased with increasing LAP index (odds ratio [OR]=1.0011, 95% confidence interval [CI]= 1.0001-1.0021). Compared to participants in LAP quartile 1, participants in LAP quartile 3 exhibited the highest risk for depression (OR=1.43, 95% CI: 1.03-1.99). Subgroup analysis demonstrated a stronger association between the LAP index and depression in men (OR= 1.002, 95% CI= 1.001-1.004) and in those with hypertension (OR=1.002, 95% CI=1.000-1.003). Additionally, smoothed curve fitting and GAM regression demonstrated a positive linear correlation between the LAP index and depression.

CONCLUSIONS

These findings suggest that individuals with a higher LAP index may be at greater risk for depression, particularly among men and those with hypertension. Further studies are required to confirm these findings.

Anti-inflammatory diet reduces risk of metabolic dysfunction-associated fatty liver disease among US adults: a nationwide survey

BACKGROUND

While dietary intervention was an important public health strategy for the prevention and intervention of metabolic dysfunction-associated fatty liver disease (MAFLD), the effect of diet-induced inflammation on MAFLD has not been studied in detail. Therefore, we aimed to analyze the relationship between dietary inflammatory index (DII) and MAFLD.

METHODS

This study included data from the National Health and Nutrition Examination Survey 2017-2018. MAFLD was diagnosed based on the presence of hepatic steatosis, as determined by transient elastography, along with evidence of either overweight/obesity, type 2 diabetes mellitus, or metabolic dysfunction. DII was calculated using 27 dietary components collected through 24-hour dietary recall questionnaire. Weighted logistic regression was used to analyze the relationship between DII and MAFLD and its main components in three different models. Subgroup analyses were performed by age, sex, and alcohol use.

RESULTS

A total of 1991 participants were included, and the MAFLD group had higher DII scores. After adjusting for age, sex, race, physical activity, smoking status, and alcohol use, the highest quartile of DII was associated with increased risk of MAFLD (OR:2.90, 95% CIs: 1.46, 5.75). Overweight/obesity, central obesity, low high density lipoprotein cholesterol (HDL-C) and high C-reactive protein (CRP) also shared the same characteristics in the main components of MAFLD. Results were consistent across subgroups (age, sex, and alcohol use).

CONCLUSIONS

A higher DII diet was positively associated with the risk of MAFLD in American adults, particularly as related to overweight/obesity, central obesity, high CRP level, and low HDL-C level.

Association of Dietary Inflammatory Index and Thyroid Function in Patients with Hashimoto's Thyroiditis: An Observational Cross-Sectional Multicenter Study

Background and Objectives: The available research suggests that dietary patterns with high inflammatory potential, as indicated by a high DII score, may exacerbate inflammation and potentially influence thyroid function. Therefore, the aim of this study was to investigate the associations between the inflammatory potential of a diet and thyroid function in adults with Hashimoto's thyroiditis (HT). Materials and Methods: A total of 149 adults diagnosed with Hashimoto's thyroiditis were enrolled in this observational, cross-sectional, multicenter study. The Dietary Inflammatory Index (DII®) was calculated using a 141-item food frequency questionnaire (FFQ). The serum levels of the thyroid-stimulating hormone (TSH), free thyroxine (fT4), thyroid peroxidase antibodies (TPO-Ab), and high-sensitivity C-reactive protein (hsCRP) were determined. Results: The DII® scores ranged from -3.49 (most anti-inflammatory) to +4.68 (most pro-inflammatory), whereas three DII® tertile ranges were defined as <-1.4, -1.39 to +1.20, and >+1.21, respectively. Participants in tertile 1 (more anti-inflammatory diet) had significantly higher levels of fT4 than those adhering to a more pro-inflammatory diet (p = 0.007). The levels of hsCRP and TSH appeared to increase with increasing the DII® score, but without statistical significance. A significant association was found between the DII® and TSH (β = 0.42, p < 0.001) and between DII® and free thyroxine (β = 0.19, p < 0.001). After adjustment for age, gender, energy intake, and physical activity, a significant positive correlation remained between the DII® and TSH (β = 0.33, p = 0.002) and between the DII® and body mass index (BMI) (β = 0.14, p = 0.04). Conclusions: Adherence to an anti-inflammatory diet appears to be beneficial in patients with Hashimoto's thyroiditis, suggesting that dietary modification aimed at lowering DII® levels may be a valuable strategy to improve clinical outcomes in these patients.

The association between dietary inflammatory index and dietary total antioxidant capacity and Hashimoto's thyroiditis: a case-control study

BACKGROUND

Hashimoto's thyroiditis (HT) is an inflammatory disease characterized by increased reactive oxygen species. Diets rich in anti-inflammatory and antioxidant properties may be linked to a reduced risk of developing HT. The aim of this study was to investigate the association between the dietary inflammatory index (DII) and dietary total antioxidant capacity (DTAC) with HT in Iranian adults.

METHODS

The study was a hospital-based case-control study conducted on 230 participants (115 cases and 115 controls). Dietary intake was assessed using a food frequency questionnaire (FFQ). The FFQ data were used to calculate DII and DTAC scores. Anthropometric measurements, thyroid function, and antibody tests were evaluated using standard methods. Multivariable logistic regression analysis was performed in both raw and adjusted models to determine the association between DII and DTAC scores with HT.

RESULTS

The average age of the participants was 39.76 ± 9.52 years. The mean body mass index in the case and control groups was 28.03 ± 6.32 and 26.43 ± 5.13 (kg/m2), respectively (P = 0.036). In the HT group, the DII level was higher (P < 0.001) and the DTAC level was lower than those in the healthy group (P = 0.047). In the multivariable logistic regression model, after adjusting for confounding factors, subjects in the last tertile of DII had a nonsignificantly higher HT risk than those in the first tertile (OR = 1.75; 95% CI = 0.83-3.65; P = 0.130). Regarding DTAC, the subjects in the last tertile of DTAC had a significantly decreased risk of HT (OR = 0.47; 95% CI = 0.23-0.98; P = 0.043) compared to those in the first tertile. The DII had a positive correlation with anti-thyroid peroxidase antibody (anti-TPO), thyroglobulin antibodies (TG-Ab) and thyroid-stimulating hormone, while DTAC had a negative correlation with anti-TPO and TG-Ab (P < 0.050).

CONCLUSION

The increase in DII is not associated with an increase in the risk of HT, while DTAC can significantly reduce its risk. Having an anti-inflammatory and antioxidative diet can be effective in improving thyroid function. These conclusions should be confirmed in additional prospective studies.

Obesity aggravates the role of C-reactive protein on knee pain: A cross-sectional analysis with NHANES data

OBJECTIVE

To examine the relationship between C-reactive protein (CRP) and knee pain, and further explore whether this association is mediated by obesity.

METHODS

The population was derived from 1999 to 2004 National Health and Nutrition Examination Survey. Logistic regression was used to analyze the relationship between CRP and knee pain in three different models, and the linear trend was analyzed. A restricted cubic spline model to assess the nonlinear dose-response relationship between CRP and knee pain. Mediation analyses were used to assess the potential mediating role of obesity. Subgroup analyses and sensitivity analyses were performed to ensure robustness.

RESULTS

Compared with adults with lower CRP (first quartile), those with higher CRP had higher risks of knee pain (odds ratio 1.39, 95% confidence interval 1.12-1.72 in third quartile; 1.56, 1.25-1.95 in fourth quartile) after adjusting for covariates (except body mass index [BMI]), and the proportion mediated by BMI was 76.10% (p < .001). BMI and CRP were linear dose-response correlated with knee pain. The odds ratio for those with obesity compared with normal to knee pain was 2.27 (1.42-3.65) in the first quartile of CRP, 1.99 (1.38-2.86) in the second, 2.15 (1.38-3.33) in the third, and 2.92 (1.72-4.97) in the fourth.

CONCLUSION

Obesity mediated the systemic inflammation results in knee pain in US adults. Moreover, higher BMI was associated with higher knee pain risk in different degree CRP subgroups, supporting an important role of weight loss in reducing knee pain caused by systemic inflammation.

The association between serum soluble α-Klotho and thyroid profile among adults from NHANES 2007-2012

BACKGROUND

Thyroid hormone is the key endocrine regulator of growth, development, metabolism, and other bodily functions. α-Klotho has been involved in the aging process and acts as an endocrine factor involved in the regulation of various metabolic processes in humans. However, the relationship between α-Klotho and thyroid profile has not been uniformly recognize.

OBJECTIVE

To determine the relationship between α-Klotho and thyroid profile in adult individuals.

METHODS

Population data of 4614 adult individuals were obtained from the NHANES database during the period of 2007-2012. Weighted multivariable regression analysis was performed using a general linear model with serum α-Klotho as the independent variable and thyroid profile as the dependent variables, respectively. The generalized additive model was used for smoothing curve fitting and threshold effect analysis.

RESULTS

α-Klotho was associated with a slightly higher FT3, TT3 and TT4 level in unadjusted and adjusted regression models. However, a higher α-Klotho level was associated with a lower TSH level. After α-Klotho was grouped as quantiles with reference (Q1), α-Klotho still showed a statistically significant positive correlation with FT3 and TT3 levels in Q2, Q3 and Q4. In addition, α-Klotho was positively corrected with TT4, but negatively associated with TSH in Q4.

CONCLUSIONS

Serum soluble α-Klotho was positively associated with FT3, TT3 and TT4, but negatively correlated with TSH. The significant effect of α-Klotho on thyroid profile suggests its potential as a predictive marker of thyroid functions, indicating its possible involvement in the regulation of thyroid hormone secretion.

Serum FT3/FT4, but not TSH is associated with handgrip strength in euthyroid U.S. population: evidence from NHANES

Objective

Although several studies have examined the relationship between thyroid function and muscle strength, their population primarily derived from Asian areas, and their results were controversial. Thus, this study aimed to explore the association between thyroid function and handgrip strength (HGS) in the U.S. population.

Methods

A total of 1,067 participants from NHANES were categorized into three different age groups including young (<45 years), middle (45~64 years), and old (≥65 years) age groups. Thyroid function was measured by the competitive binding immune-enzymatic assays, while HGS was examined by a trained evaluator using a dynamometer. The weighted multiple linear regression models were used to examine the association between thyroid function and handgrip strength. The restricted cubic splines were employed to explore the non-linear relationship between these two variables. All statistical analyses were performed using the SPSS version 20.0 and R software.

Results

After adjustment for potential covariates, FT3/FT4, but not TSH was positively associated with HGS in middle age group (β=0.091, t=2.428, P=0.016). The subgroup analysis by sex revealed that the positive association between FT3/FT4 and HGS was observed in the middle age group for both male and female participants (β=0.163, t=2.121, P=0.035; β=0.157, t=2.180, P=0.031). The RCS analysis showed a statistically significant non-linear association between FT3/FT4 and HGS in overall population (P for non-linear=0.026). After adjustment for covariates, men with low HGS had a significant lower FT3/FT4 than those without low HGS in old age group (P=0.013). There was a significant increase in TSH level for female participants with low HGS in old age group compared to those with normal HGS (P=0.048).

Conclusions

This study demonstrated FT3/FT4, but not TSH, was positively associated with HGS in middle age group, and the different association was observed in men in middle age group when participants were stratified by sex. Future longitudinal cohort study should be conducted to reveal the causal relationship between thyroid function and muscle strength.

The Relationship Between Fermented Dairy Consumption with Cognitive Function Among Older US Adults: Data from the NHANES 2011-2014

Background

The aging global population has led to an increased burden of cognitive impairment in older adults.

Objective

This study examined the relationship between fermented dairy intake and cognitive function in this population.

Methods

Yogurt, cheese, and fermented dairy consumption were assessed through two 24-hour dietary recall interviews, categorized into low, medium, and high intake groups. Multivariate linear regression was employed to examine the relationship between fermented dairy intake and cognitive tests, including the Alzheimer's Disease Word Learning Immediate Recall Test (CERAD-IRT), CERAD Delayed Recall Test (CERAD-DRT), Animal Fluency Test (AFT), Digit Symbol Substitution Test (DSST), and global cognitive z-scores, adjusting for potential confounding factors.

Results

The study comprised 2,462 participants (average age 69.34±6.75 years, 52.07% female). Among yogurt consumers, global cognition and AFT z-scores are notably higher than non-consumers. Conversely, individuals who consume cheese display significantly lower CERAD-DRT z-scores. Compared to participants not intake fermented dairy, consumers of fermented dairy show significantly higher AFT and DSST z-scores and lower CERAD-DRT z-scores. Moreover, when categorizing individuals based on their intake of fermented dairy, those with low and medium consumption show significantly higher AFT and DSST z-scores, as well as significantly lower CERAD-DRT z-scores compared to non-consumers.

Conclusions

Our study suggests that moderate consumption of fermented dairy products is associated with better executive function and verbal fluency in the elderly.

Association between combined exposure to dioxins and arthritis among US adults: a cross-sectional study

Dioxins and dioxin-like compounds (DLCs) are common pollutants hazardous to human health. We applied 12 dioxins and DLCs data of 1851 participants (including 484 arthritis patients) from National Health Examination Survey (NHANES) 2001-2004 and quadrupled them into rank variables. Multivariate logistic regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) models were used to explore the relationship between individual or mixed exposure to the pollutants and arthritis after adjusting for multiple covariates. In multivariable logistic regression with an individual dioxin or DLC, almost every chemical was significantly positively associated with arthritis, except PCB66 (polychlorinated biphenyl 66) and 1,2,3,4,6,7,8-heptachlorodibenzofuran (hpcdf). The WQS model indicated that the combined exposure to the 12 dioxins and DLCs was positively linked to arthritis (OR: 1.884, 95% CI: 1.514-2.346), with PCB156 (weighted 0.281) making the greatest contribution. A positive trend between combined exposure and arthritis was observed in the BKMR model, with a posterior inclusion probability (PIP) of 0.987 for PCB156, which was also higher than the other contaminants.

Cardiometabolic-related dietary patterns and thyroid function: a population-based cross-sectional study

BACKGROUND

Little is known about the association of dietary patterns with thyroid function. Since thyroid function and cardiometabolic variables are inter-related, we investigated whether cardiometabolic-related dietary patterns are associated with thyroid function.

METHODS

This cross-sectional study included 3520 Tehran Lipid and Glucose Study participants. Reduced rank regression was used to find dietary patterns with body mass index, serum fasting glucose, triglycerides, HDL-C, and systolic and diastolic blood pressures as response variables. Two patterns were retained, one based on 35 food groups (native-based pattern) and the other based on the European Prospective Investigation into Cancer and Nutrition Germany (EPIC) food grouping (n = 33). A confirmatory cardio-metabolic dietary pattern was also created according to the weight of food groups proposed by the Framingham Offspring Study (FOS). The association of each pattern with thyroid-stimulating hormone (TSH), free thyroxine, and thyroid peroxidase antibody (TPOAb) and the odds of thyroid dysfunction was examined by linear and logistic regression, respectively.

RESULTS

The two exploratory dietary patterns were highly correlated and associated with greater TSH levels in euthyroid participants. The adjusted odds ratio (95% CI) of subclinical hypothyroidism per one standard deviation was 1.14 (1.01, 1.28) for the native-based pattern and 1.16 (1.03, 1.31) for the EPIC-based pattern. The odds of subclinical hypothyroidism was significantly greater in the second and third tertiles of the native-based pattern compared to the first tertile in the adjusted model (p-trend = 0.005). The odds of subclinical hypothyroidism increased across the tertiles of the EPIC-based pattern, but the odds was significantly higher only in tertile 3 compared to tertile 1, with an OR (95% CI) of 1.44 (1.07, 1.94) in the adjusted model. The adjusted odds of clinical hypothyroidism were greater in tertile 3 of the native-based pattern compared with tertile 1 (OR = 1.65, 95% CI 1.04, 2.62). The patterns were unrelated to hyperthyroidism or TPOAb positivity. The FOS-based confirmatory score was unrelated to thyroid function.

CONCLUSIONS

A diet high in fast foods, soft drinks, and legumes and low in confectionery, potatoes, butter, and jam and honey was associated with higher TSH levels in euthyroidism and higher odds of subclinical hypothyroidism.

Relationship between thyroid function and dietary inflammatory index in Hashimoto thyroiditis patients

Inflammation is closely related to the changes of thyroid function in Hashimoto thyroiditis patients. Certain nutrients or dietary habits can alter the levels of autoantibodies in Hashimoto thyroiditis. However, it remains unclear whether dietary inflammation affects thyroid function in patients with Hashimoto thyroiditis. The purpose of this study was to assess the relationship between dietary inflammation and thyroid function in Hashimoto thyroiditis patients using data from the National Health and Nutrition Examination Survey. We employed weighted multivariable linear regression, subgroup analyses, and interaction analysis to explore the relationship between thyroid function and dietary inflammatory index. We found that dietary inflammatory index was positively correlated with TSH and total T4. Interaction analysis found an interaction between urinary iodine concentration and FT3, but subgroup analysis for different levels of urinary iodine concentration did not get statistically significant results. Hashimoto thyroiditis patients with more pro-inflammatory diet habits had higher levels of TSH and TT4. In order to prevent hypothyroidism more effectively in patients with Hashimoto thyroiditis, it is essential to control dietary inflammation. However, it is still necessary to design a better prospective cohort study to verify the causal relationship.

Exploring the association between triglyceride-glucose index and thyroid function

BACKGROUND

Thyroid dysfunction is associated with abnormal glucose-insulin homeostasis, and the triglyceride-glucose (TyG) index has been recommended as a convenient surrogate of insulin resistance (IR). This study aimed to investigate the relationship between TyG and thyroid function in the US population.

METHODS

 We analyzed data from the National Health and Nutrition Examination Survey (NHANES) conducted from 2007 to 2012 in a cross-sectional manner. Aside from conventional thyroid parameters, our study evaluated the central sensitivity to thyroid hormones (THs) using the thyroid feedback quantile-based index (TFQI), thyrotropin resistance index (TT4RI), and thyrotropin index (TSHI). To evaluate peripheral sensitivity to THs, we calculated the ratio of free triiodothyronine (FT3) to free thyroxine (FT4) and the sum activity of peripheral deiodinases (SPINA-GD). In the 1848 adults, multivariable linear regression, subgroup, and interaction analyses were employed to estimate the association between TyG and thyroid parameters. The nonlinear relationship was addressed by smooth curve fittings and generalized additive models.

RESULTS

After adjusting covariates, we demonstrated a significant negative association between TyG and FT4 (β = - 0.57, p < 0.001), and a positive relationship between TyG and thyroid-stimulating hormone (β = 0.34, p = 0.037), as well as TgAb (β = 17.06, p = 0.005). Subgroup analysis indicated that the association between TyG and TgAb was more pronounced in the female subjects (β = 32.39, p < 0.001, p for interaction = 0.021). We also confirmed an inverse correlation between TyG and central sensitivity to THs, as assessed by TSHI and TT4RI (βTSHI = 0.12, p < 0.001; βTT4RI = 2.54, p = 0.023). In terms of peripheral sensitivity to THs, we found a significant positive correlation between TyG and FT3/FT4 (β = 0.03, p = 0.004), and SPINA-GD (β = 2.93, p = 0.004).

CONCLUSION

The present study established a noteworthy association between TyG and thyroid parameters, indicating a strong link between IR and thyroid dysfunction. Further investigations are warranted to validate these results.

Effects of dietary inflammatory index, blood lead levels, and flavonoid intake on stroke risk in older Americans: A cross-sectional study

OBJECTIVES

We aimed to investigate the relationship between dietary flavonoids, the dietary inflammatory index (DII), blood lead levels, and stroke and evaluate how these factors interact with one another in relation to stroke.

MATERIALS AND METHODS

We analyzed data from 3675 older American adults aged ≥60 years, obtained from the National Health and Nutrition Examination Survey. Since this database does not specifically differentiate between hemorrhagic and ischemic strokes, our data include both types. We utilized the DII to assess the inflammatory potential of the diet, calculated using 24 h dietary recalls. To determine the association between dietary flavonoids, blood lead levels, DII, and stroke, we performed multivariate logistic regression, subgroup analysis, and restricted cubic splines. We modeled additive interactions to assess the relationship between blood lead levels and DII.

RESULTS

A high intake of flavonols, flavan-3-ols, and total flavonoids correlated negatively with stroke risk, whereas blood lead levels had a positive association. After adjusting for confounders, stroke risk was found to increase with higher DII. Restricted cubic splines analysis revealed that flavan-3-ols, total flavonoids, blood lead levels, and DII were linearly related to stroke, while the relationships with flavonoids and flavonols were nonlinear. Additionally, a significant interaction was detected between high DII and elevated blood lead levels in relation to stroke risk.

CONCLUSIONS

Intake of flavan-3-ol, flavanols, and total flavonoids is negatively associated with stroke risk, while higher blood lead levels and DII are positively related to it. High DII and elevated blood lead levels interact synergistically to influence stroke risk.

The METS-IR is independently related to bone mineral density, FRAX score, and bone fracture among U.S. non-diabetic adults: a cross-sectional study based on NHANES

AIM

The purpose of this study was to investigate the association between the metabolic score for insulin resistance (METS-IR) and bone mineral density (BMD) in American non-diabetic adults.

METHODS

We conducted a cross-sectional study with 1114 non-diabetic adults from the National Health and Nutrition Examination Survey cycle (2013-2014). The associations between METS-IR and BMD of total femur and spine were assessed by the multiple linear regression and verified the non-linear relationship with a smooth curve fit and threshold effect model. Furthermore, we evaluated the relationship between METS-IR, FRAX score, and history of bone fractures.

RESULTS

We found that BMD of the total femur and spine increased by 0.005 g/cm3 and 0.005 g/cm3, respectively, for a one-unit increase of METS-IR in all participants. This positive association was more pronounced among higher METS-IR participants, and there was a non-linear relationship, which was more significant when the MTTS-IRfemur was < 41.62 or the METS-IRspine was < 41.39 (βfemur = 0.008, βspine = 0.011, all P < 0.05). We also found that METS-IR was positively correlated with both FRAX scores in all female participants. However, METS-IR was positively correlated only with the 10-year hip fracture risk score in male participants with fractures. No significant association between METS-IR and a history of bone fractures.

CONCLUSIONS

In American non-diabetic adults, there is a correlation between elevated levels of METS-IR within the lower range and increased BMD as well as decreased risk of fractures, suggesting that METS-IR holds promise as a novel biomarker for guiding osteoporosis (OP) prevention. However, it is important to carefully balance the potential benefits and risks of METS-IR in OP.

Autoimmune Thyroid Disorders: The Mediterranean Diet as a Protective Choice

Autoimmune thyroid diseases are on the rise worldwide, and such a rapid increase is mainly driven by environmental factors related to changed lifestyles in "modern" societies. In this context, diet seems to play a crucial role. An unhealthy high-energy diet, rich in animal fat and proteins, salt and refined sugars (the so-called "Western diet") negatively influences the risk of autoimmunity by altering the immune balance and the gut microbiota composition, enhancing oxidative stress and promoting inflammation. In contrast, the Mediterranean diet represents a unique model of healthy eating, characterized by a high intake of food from vegetable sources, a low consumption of saturated fats in favor of unsaturated fats (mainly, olive oil), a moderate consumption of fish (typically, the small oily fishes) and dairy products, as well as a moderate consumption of wine at meals, and a low intake of meat. Thanks to its nutritional components, the Mediterranean Diet positively influences immune system function, gut microbiota composition, and redox homeostasis, exerting anti-oxidants, anti-inflammatory, and immunomodulatory effects. The present review was aimed at exploring the existing knowledge on the correlations between dietary habits and thyroid autoimmunity, to evaluate the role of the Mediterranean diet as a protective model.

The relationship between dietary inflammatory index values and thyroid function in the US adult population: An analysis of the NHANES 2007-2012 cohort

OBJECTIVE

Researchers have developed the Dietary Inflammatory Index (DII) as a tool to quantify the inflammatory potential of a given diet. Higher DII scores indicated a more proinflammatory diet. While inflammation is known to have a strong impact on thyroid function, the precise nature of the association between DII scores and thyroid function has yet to be clarified. This study was conducted with the goal of exploring this relationship in a representative population of adults from the United States.

METHODS

For this study, we used data from the National Health and Nutrition Examination Survey (NHANES). Standardized questionnaires were used to collect demographic and dietary data from the participants, and laboratory tests were used to collect data on the participants' thyroid parameters and other relevant data. Linear regression models and smoothed curve fitting were used to assess the relationship between DII scores and thyroid function, with weighted data analyses and subgroup analyses being conducted as appropriate.

RESULTS

In total, 7712 subjects were recruited from the NHANES 2007-2012 cohort. Their weighted mean age was 44.87 (0.47) years, mean DII score was 1.41 (0.05). Mean FT3 was 3.20 (0.01) pg/mL and mean TT4 was 7.81 (0.03) µg/dL. In adjusted analyses, higher DII values were related to increases in FT3 (β = .007; p = .027) and TT4 (β = .050; p = .005) levels. Subgroup analyses showed a negative correlation between FT3 levels and DII scores in a population with high urinary iodine concentrations.

CONCLUSION

These data indicate that the consumption of a more proinflammatory diet, as evidenced by elevated DII scores, is correlated with significant increases in FT3 and TT4 levels. However, for people with high urinary iodine concentrations, a more proinflammatory diet was associated with lower FT3 levels. Additional research will be vital to clarify the mechanistic basis for these findings.

Association between inflammatory potential of diet and self-reported severe headache or migraine: A cross-sectional study of the National Health and Nutrition Examination Survey

OBJECTIVE

Inflammation plays an important role in migraine development. Dietary interventions that reduce the inflammatory state are effective for migraine prophylaxis. However, little is yet known about the association between the inflammatory potential of diet and migraine in the general US adult population. The aim of this study was to evaluate whether the inflammatory potential of diet is associated with severe headache or migraine in US adults.

METHODS

This cross-sectional study analyzed data from adult participants in the 1999-2004 National Health and Nutrition Examination Survey. Severe headache or migraine was determined based on self-reported information. Severe headache or migraine was defined as an affirmative response to the question: "Have you had a severe headache or migraine in the past 3 mo?" The dietary inflammatory index (DII) was used to assess the inflammatory potential of the diet. Multivariable logistic regression models were used to determine the odds ratio (OR) and 95 % confidence interval (95% CI) for the association between DII and severe headache or migraine. A multivariable-adjusted restricted cubic spline model was constructed to establish the OR curves at 3 knots to examine the possible non-linear dose-response association between DII and severe headache or migraine.

RESULTS

Of 10359 participants included in this study (mean age, 46.3 [0.3] y; 5116 [49%] men), 2083 (22%) reported previous episodes of severe headache or migraine, whereas 8276 (78%) did not. After adjusting for potential confounders, the DII score was associated with severe headache or migraine (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.03-1.15; P = 0.003). Compared with participants with the lowest tertile (T1) of DII score (i.e., T1; ≤-4.42 to ≤0.77), those with the highest tertile (i.e., T3; <2.44 to ≤5.18) had an adjusted OR for severe headache or migraine of 1.46 (95% CI, 1.20-1.77; P < 0.001). The multivariable restricted cubic spline showed a non-linear association between DII and severe headache or migraine (P = 0.012). In two piecewise regression models, the adjusted OR of developing a severe headache or migraine was 1.19 (95% CI, 1.04-1.37; P = 0.012) in participants with a DII score ≥1.48, whereas there was no association between DII and severe headache or migraine in participants with a DII score <1.48. Subgroup analyses showed that DII was associated with severe headache or migraine in women (OR, 1.73; 95% CI, 1.31-2.28), individuals 20 to 50 y of age (OR, 1.66; 95% CI, 1.29-2.14), those who were married or living with a partner (OR, 1.49; 95% CI, 1.19-1.85), individuals living alone (OR, 1.36; 95% CI, 1.02-1.81), those with a high level of education (OR, 1.72; 95% CI, 1.26-2.36), individuals with a low family income (OR, 1.58; 95% CI, 1.10-2.28), those with a medium or high family income (OR, 1.48; 95% CI, 1.17-1.86), and body mass index <25 kg/m2 (OR, 1.71; 95% CI, 1.21-2.41).

CONCLUSION

The inflammatory potential of the diet is associated with severe headache or migraine in US adults.

The Impact of Visceral Adiposity on Testosterone Levels in American Adult Men: A Cross-Sectional Analysis

BACKGROUND Testosterone decline and deficiency importantly affect men's health, and may be associated with excessive deposition of visceral adipose tissue. This study was conducted to explore the association between visceral adiposity index (VAI) and testosterone level. MATERIAL AND METHODS A total of 1551 participants from the NHANES 2013-2013 cycle and 2015-2016 cycle were selected for our analyses. The VAI index was calculated based on waist circumference (WC), body mass index (BMI), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-c), and serum testosterone was measured by isotope dilution liquid chromatography tandem mass spectrometry. Multivariable adjusted linear and logistic regression were utilized to investigate the associations between VAI index and testosterone level and testosterone deficiency, respectively. Additionally, subgroup analyses were performed to identify sensitive populations. RESULTS A total of 1551 participants with mean VAI index of 1.95±0.08 were eligible for our analysis. After adjusting for all potential cofounders, men with higher VAI index displayed a lower level of total testosterone level (ß: -11.74, 95% CI: -17.33, -6.15, P<0.0001), and higher risk of testosterone deficiency (OR: 1.24, 95% CI: 1.09, 1.40, P=0.0022). Comparing to VAI quartile 1, quartile 4 showed the most decreased testosterone level (ß: -94.59, 95% CI: -130.04, -59.14, P<0.0001), and highest risk of testosterone deficiency (OR: 5.07, 95% CI: 2.41,10.63, P<0.0001). Subgroup analysis demonstrated that VAI index was strongly related to testosterone level and testosterone deficiency in aged and obese men. CONCLUSIONS Men with higher VAI index displayed lower testosterone levels and higher risk of testosterone deficiency, especially in aged men and obese men.

The Triglycerides and Glucose Index is not superior to HOMA-IR in predicting testosterone deficiency among adult males

BACKGROUND

Testosterone decline and deficiency in males have aroused increased attention in male health management, which might have a close relationship with insulin resistance (IR).

OBJECTIVES

We utilized a novel and practical IR indicator, the triglyceride-glucose (TyG) index, to investigate the association between the TyG index and serum testosterone in US adult males.

MATERIALS AND METHODS

This was a cross-sectional study based on data from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 and 2015-2016. The TyG index was calculated from fasting plasma glucose and serum triglyceride, and serum testosterone was measured by isotope dilution liquid chromatography tandem mass spectrometry in NHANES.

RESULTS

A total of 2186 male participants aged more than 20 years old were included, and the mean TyG index was 8.72 ± 0.71. Participants with a higher TyG index showed a lower level of total testosterone (β = -45.83, 95% CI: -58.50, -33.15, p < 0.0001) and a higher risk of testosterone deficiency (OR = 1.80, 95% CI: 1.46, 2.21, p < 0.0001) after we adjusted for all potential cofounders. Males in TyG index tertile 3 had a 113% (95% CI: 1.50, 3.02, p < 0.0001) higher risk of testosterone deficiency than those in tertile 1. Subgroup analysis stratified by diabetes condition indicated that the TyG index might be a good predictor of testosterone decline or deficiency in either people with or without diabetes. However, ROC cure analysis indicated that a larger area under the curve was found in the homeostasis model assessment of insulin resistance (HOMA-IR) (0.71, 95% CI: 0.68,0.74) than in the TyG index (0.67, 95% CI: 0.64, 0.70).

CONCLUSIONS

Males with a higher TyG index tended to have a higher risk of testosterone decline or even testosterone deficiency. However, the predictability of the TyG index for testosterone deficiency was not better than that of HOMA-IR. More well-designed studies are still needed to validate this relationship.

Relationship between diet-related inflammation and bone health under different levels of body mass index

BACKGROUND

Osteoporosis is a major public health problem. Dietary inflammatory preference and body mass index (BMI) are emerging factors that tends to affect bone health. There is limited evidence regarding the joint influence of BMI and dietary status on the bone health. This study aimed to investigate the relationship between dietary inflammatory index (DII) and bone health among adults under different levels of BMI utilizing the National Health and Nutrition Examination Survey (NHANES).

METHODS

Data were collected from 2005-2010, 2013-2014 to 2017-2018 in NHANES. In total, 10,521 participants who aged ≥ 20 years and had complete data for dietary intake interview, bone mineral density (BMD) and bone mineral content (BMC) were included. DII was performed to evaluate the dietary inflammatory potential based on dietary intake interview. We evaluated bone health by femoral neck BMD and BMC measured by dual energy X-ray absorptiometry. Weighted multivariable linear regression and BMI-stratified subgroup analysis were performed.

RESULTS

The average DII score for 10,521 participants was 1.24 ± 0.04, mean femoral neck BMD was 0.82 ± 0.00 g/cm² and mean BMC was 4.37 ± 0.01 g. In the fully adjusted model, there was a negative correlation between DII with BMD (β = - 0.016, P < 0.001) and BMC (β = - 0.011, P < 0.001) in the most anti-inflammatory diet. Using BMI-stratified subgroup analysis, this correlation became more evident in both the overweight (BMD: β = - 0.024, P < 0.001; BMC: β = - 0.058, P = 0.042) and obese groups (BMD: β = - 0.015, P = 0.049; BMC: β = - 0.009, P = 0.042), while this correlation was opposite in DII tertile 2 (middle DII score) in the underweight group (BMD: β = 0.047, P = 0.038; BMC: β = 0.274, P = 0.010).

CONCLUSION

Relationship between higher consumption of pro-inflammatory and increased risk of lower BMD and BMC was only existed in overweight and obese participants.

Association between the triglyceride–glucose index and chronic kidney disease in adults

BACKGROUND

Chronic kidney disease (CKD) is characterized as a progressive dysfunction of the kidney, and it might have a close relationship with insulin resistance. We utilized the triglyceride-glucose (TyG) index, a reliable marker of insulin resistance, to evaluate the association between the TyG index and CKD in adults from the general population.

METHODS

This was a cross-sectional study obtaining data from the 2015-2018 National Health and Nutrition Examination Survey. The estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) served as kidney function indicators. We defined CKD as the existence of either low eGFR (eGFR < 60 mL/min/1.73 m² BSA) or albuminuria (UACR > 30 mg/g). Multivariate regressions, correlated subgroup analyses, and interaction terms were performed in this study.

RESULTS

For 4361 recruited participants, the mean TyG index was 8.60 ± 0.68, and the prevalence of CKD was 13.35%. Participants with a higher TyG index showed a higher UACR level (β = 25.10, 95% CI: 6.76, 43.44, P = 0.0074) and higher levels of CKD (OR = 1.34, 95% CI: 1.13, 1.59, P = 0.0006). The positive relationship between the TyG index and CKD became stronger and remained significant in the overweight (OR = 1.61, 95% CI: 1.18, 2.20, P = 0.0027) and obese (OR = 2.48, 95% CI: 1.95, 3.15, P < 0.0001) groups and in people with diabetes (OR = 1.94, 95% CI: 1.46, 2.56, P < 0.0001).

CONCLUSIONS

Higher TyG index was strongly associated with a higher UACR level and higher values of albuminuria and CKD, which might be useful in kidney function screening especially among people in disadvantageous socioeconomic conditions with no availability for direct measurement of kidney function. However, more well-designed studies are still needed to validate this relationship.

Potential role of inflammation in relation to dietary sodium and β-carotene with non-alcoholic fatty liver disease: a mediation analysis

Background

High sodium intake has been linked to the prevalence of non-alcoholic fatty liver disease (NAFLD), but underlying mechanism remains unclear. This study aims to explore the role of chronic inflammation in the association between sodium and NAFLD. We also observed whether β-carotene, which had a strong anti-inflammatory effect, lowers the odds of NAFLD.

Methods

We performed mediation analyses to assess the mediating effects of C-reactive protein (CRP) and red cell distribution width (RDW) on the relationship between dietary sodium and NAFLD defined by the hepatic steatosis index (HSI) and the fatty liver index (FLI), respectively.

Results

A total of 6725 participants were included in this study. Compared with the high sodium-low carotene group, participants in the high sodium-high carotene group had 16% and 26% lower odds for HSI and FLI-defined NAFLD, respectively. There were positive indirect effects of dietary sodium intake on the HSI-defined NAFLD (indirect effect: 0.0057, 95% CI: 0.0021–0.0091, P < 0.0001), as well as the FLI defined NAFLD (indirect effect: 0.0081, 95% CI: 0.0024–0.0162, P < 0.0001) when C-reactive protein (CRP) was considered as a mediator. The mediating effects were somewhat attenuated after further adjusting for dietary β-carotene intake. Similar results were found when RDW was considered as a mediator in the HSI-defined NAFLD analysis.

Conclusions

Higher sodium intake increases the odds of NAFLD by upregulating inflammation. Dietary β-carotene may attenuate this association by down regulating inflammation.

A Proinflammatory Diet May Increase Mortality Risk in Patients with Diabetes Mellitus

This was an observational study based on the National Health and Nutrition Examination Survey (NHANES) and National Death Index (NDI) 2009–2014 which aimed to validate whether a proinflammatory diet may increase mortality risk in patients with diabetes mellitus. Dietary inflammatory potential was assessed by dietary inflammatory index (DII) based on 24 h dietary recall. Mortality follow-up information was accessed from NDI, which was then merged with NHANES data following the National Center for Health Statistics (NCHS) protocols. For 15,291 participants from the general population, the average DII was 0.37 ± 1.76 and the prevalence rate of diabetes was 13.26%. DII was positively associated with fasting glucose (β = 0.83, 95% CI: 0.30, 1.36, p = 0.0022), glycohemoglobin (β = 0.02, 95% CI: 0.01, 0.03, p = 0.0009), and the risk of diabetes (OR = 1.05, 95% CI: 1.01, 1.09, p = 0.0139). For 1904 participants with diabetes and a median follow-up of 45 person-months, a total of 178 participants with diabetes died from all causes (mortality rate = 9.34%). People with diabetes who adhered to a proinflammatory diet showed a higher risk of all-cause mortality (HR = 1.71, 95%CI: 1.13, 2.58, p = 0.0108). In summary, DII was positively associated with diabetes prevalence and a proinflammatory diet may increase mortality risk in patients with diabetes mellitus.

Relationship between the dietary inflammatory index and kidney stone prevalence

PURPOSE

This study aimed to investigate the association between the dietary inflammatory index and lifetime kidney stone prevalence.

METHODS

We performed a cross-sectional study utilizing the 2013-2014 National Health and Nutrition Examination Survey data. Data were available on 2192 participants aged > 20 years with a complete kidney stone history and 24 h dietary intake interview. Weighted multivariable linear regression, subgroup analyses, and interaction terms were employed. Covariates including age, race, sex, energy and protein intake, total serum calcium, serum iron, PIR, phosphorus, serum/urine creatinine, HDL, glucose, diastolic and systolic pressure, education level, eGFR, BMI, albuminuria, diabetes, smoking status, and marital status were hierarchically adjusted in three different models.

RESULTS

The average dietary inflammatory index for 2192 participants was - 0.11 ± 1.73, ranging from - 4.52 to 4.28. In the fully adjusted model, participants in the highest dietary inflammatory index tertile (the most proinflammatory) had 72% higher odds of the lifetime prevalence of kidney stones than those in tertile 1 (OR = 1.72, 95% CI: 1.03, 2.88, P = 0.0367). Subgroup analysis showed that the association between the dietary inflammatory index and kidney stone history was only statistically significant in the younger age (age ≥ 60), female, Mexican American groups, married people or people without diabetes, hypertension, low eGFR, and albuminuria.

CONCLUSIONS

There is a positive association between the dietary inflammatory index and self-reported kidney stones in US adults, which indicates that dietary patterns could greatly impact kidney stone prevalence.

The Association Between Serum Palmitic Acid and Thyroid Function

AIM

Emerging evidence indicates that palmitic acid (PA) can regulate the progression and development of many diseases. However, the studies examining the association between PA and thyroid function remain sparse. We aimed to investigate the association between serum PA (sPA) and thyroid function in the US population.

METHODS

In this retrospective study, a cross-sectional analysis was performed using the data pooled from the database of the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2012. The thyroid parameters investigated were mainly free triiodothyronine (FT3), free thyroxine (FT4), total T3 (TT3), TT4, thyroglobulin (Tg), thyroid-stimulating hormone (TSH), anti-thyroglobulin antibody (TgAb), and anti-thyroperoxidase antibody (TPOAb). The central sensitivity to thyroid function was evaluated by the thyroid feedback quantile-based index (TFQI), thyrotrophin thyroxine resistance index (TT4RI), and thyrotropin index (TSHI). The FT3 to FT4 ratio (FT3/FT4) was employed to evaluate peripheral sensitivity to thyroid hormones. Multiple imputation was applied to handle the missing data, and weighted multivariable linear regression, subgroup, and interaction analyses were then employed to estimate the association between sPA and thyroid parameters.

RESULTS

In the 737 adults, after adjusting covariates, we demonstrated a significant negative association between sPA and FT4 [β = -1.078, 95% confidence interval (CI): -1.729 to -0.427], as well as a positive relationship between sPA and FT3/FT4 ratio (β = 0.073, 95% CI: 0.044 to 0.102). These results did not change on multiple imputations. In the subgroup analyses, the associations were more significant in male and obese subjects.

CONCLUSION

This investigation demonstrated the significant correlation between sPA and thyroid dysfunction, which suggested the close relationship between lipotoxicity and hypothyroidism or subclinical hypothyroidism. Future research is required to confirm these findings.

The Association Between Circulating Trans Fatty Acids and Thyroid Function Measures in U.S. Adults

BACKGROUND

There has been controversial evidence regarding the effect of trans fatty acids (TFAs) on thyroid function in animal studies, and the epidemiological studies are lacking. We aimed to investigate the potential associations between circulating TFAs and thyroid function biomarkers in a U.S. adult population sample.

METHODS

We performed a cross-sectional survey with 626 adults aged ≥20 years who participated in the National Health and Nutrition Examination Survey (NHANES) 2009-2010. Multivariable linear regression models were constructed to elucidate the relationships between circulating concentrations of TFAs (palmitelaidic acid, vaccenic acid, elaidic acid, linoelaidic acid and the sum of the four TFAs) and a panel of thyroid function measures.

RESULTS

For 626 adults, positive associations were found between palmitelaidic acid, elaidic acid and total thyroxine (TT4), between palmitelaidic acid and total triiodothyronine (TT3), and between linolelaidic acid and thyroid stimulating hormone (TSH), while linolelaidic acid was negatively associated with free thyroxine (FT4) (all P<0.05). Besides, the four TFAs and the sum TFAs were positively associated with free triiodothyronine (FT3). Vaccenic acid, elaidic acid, linoelaidic acid and the sum TFAs were positively associated with FT3/FT4, while the four TFAs and the sum TFAs were negatively associated with FT4/TT4 (all P<0.05). In stratified analysis, the associations between thyroid function measures and the ratios remained significant in female. For men, linolelaidic acid was negatively associated with FT4 and elaidic acid and the sum TFAs were positively associated with FT3. Furthermore, the associations between TFAs and FT3/FT4 remained significant.

CONCLUSION

Our findings revealed that TFAs exposure was associated with serum biomarkers of thyroid function. More researches are needed to evaluate the long-term health outcomes of these findings.

Association between Sensitivity to Thyroid Hormone Indices and Bone Mineral Density in US Males

OBJECTIVES

Thyroid hormone is acknowledged as a pivotal factor in skeletal development and adult bone maintenance. However, available data about the relationship between sensitivity to thyroid hormone and bone mineral density (BMD) remain limited and conflicting. The purpose of the study was to explore the complex relationship between sensitivity to thyroid hormone indices and BMD using cross-sectional analysis.

METHODS

An overall sample of 3,107 males from the National Health and Nutrition Examination Survey (NHANES) was studied in the study. The thyroid hormone sensitivity indices included free triiodothyronine/tree thyroxine (FT3/FT4), thyroid-stimulating hormone index (TSHI), thyrotroph thyroxine resistance index (TT4RI), and thyroid feedback quantile-based index (TFQI). Given the complex study design and sample weights, the correlation between sensitivity to thyroid hormone indices and BMD was evaluated through multivariate linear regression models, and extra subgroup analyses were performed to examine the robustness of the results.

RESULTS

Among the 3,107 participants, we demonstrated that FT3/FT4 was negatively correlated with lumbar BMD (β = -0.0.35, 95% CI: -0.084-0.013, P < 0.05). In the terms of central sensitivity to thyroid hormone, TFQI showed a significant negative relationship with the BMD of the lumbar (β = -0.018, 95% CI: -0.033 to -0.003, P < 0.05), total femur (β = -0.020, 95% CI: -0.035 to -0.006, P < 0.01), and femur neck (β = -0.018, 95% CI: -0.031 to -0.005, P < 0.01). In the subgroup analyses stratified by body mass index (BMI), the significant negative correlation between TFQI and lumbar BMD remained in the male participants with BMI between 18.5 and 24.9 kg/m².

CONCLUSIONS

Decreased indices of sensitivity to thyroid hormones are strongly associated with increased lumbar BMD, suggesting that the dysfunction of peripheral and central response to thyroid hormone might contribute to bone loss. In addition, FT3/FT4 and TFQI were considered to be the preferable indicators to guide the prevention and clinical treatment of osteoporosis.