Association between Handgrip Strength and the Systemic Immune-Inflammation Index: A Nationwide Study, NHANES 2011-2014

Association of the systemic immune-inflammation index with all-cause and cardiovascular mortality in individuals with rheumatoid arthritis

The systemic immune-inflammation index (SII), a metric reflecting systemic inflammatory response and immune activation, remains underexplored concerning its correlation with mortality among rheumatoid arthritis (RA) patients. This study aimed to delineate the association between SII and both all-cause and cardiovascular mortality within the cohort of American adults diagnosed with RA, utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 1999 to 2018. The investigation extracted data from NHANES cycles between 1999 and 2018, identifying RA patients through questionnaire responses. The SII was computed based on complete blood counts, employing the formula: (platelets × neutrophils) / lymphocytes. The optimal SII cutoff value for significant survival outcomes was determined using maximally selected rank statistics. Multivariable Cox proportional hazards models assessed the relationship between SII levels and mortality (all-cause and cardiovascular) among RA patients, with subgroup analyses examining potential modifications by clinical confounders. Additionally, restricted cubic spline (RCS) analyses were conducted to explore the linearity of the SII-mortality association. The study encompassed 2070 American adults with RA, among whom 287 exhibited a higher SII (≥ 919.75) and 1783 a lower SII (< 919.75). Over a median follow-up duration of 108 months, 602 participants died. After adjustments for demographic, socioeconomic, and lifestyle variables, a higher SII was associated with a 1.48-fold increased risk of all-cause mortality (hazard ratio [HR] = 1.48, 95% confidence interval [CI] 1.21-1.81, P < 0.001) and a 1.51-fold increased risk of cardiovascular mortality (HR = 1.51, 95% CI 1.04-2.18, P = 0.030) compared to a lower SII. Kaplan-Meier analyses corroborated significantly reduced survival rates within the higher SII cohort for both all-cause and cardiovascular mortality (Pall-cause mortality < 0.0001 and Pcardiovascular mortality = 0.0004). RCS analyses confirmed a positive nonlinear relationship between SII and mortality rates. In conclusion, the SII offers a straightforward indicator of the equilibrium between detrimental innate inflammation and beneficial adaptive immunity. Our investigation, utilizing a comprehensive and nationally representative sample, reveals that elevated SII levels independently forecast a greater risk of mortality from all causes, as well as cardiovascular-specific mortality, in individuals suffering from RA. These insights underscore the clinical relevance of the SII as an affordable and readily accessible biomarker. Its incorporation into regular clinical practice could significantly enhance the precision of risk assessment and forecasting for patients with RA, facilitating more tailored and effective management strategies. Specifically, patients with high SII levels could be identified for more stringent cardiovascular risk management, including closer monitoring, lifestyle interventions, and aggressive pharmacological treatments to mitigate their increased risk of mortality.

Chronic Astrocytic TNFα Production in the Preoptic-Basal Forebrain Causes Aging-like Sleep-Wake Disturbances in Young Mice

Sleep disruption is a frequent problem of advancing age, often accompanied by low-grade chronic central and peripheral inflammation. We examined whether chronic neuroinflammation in the preoptic and basal forebrain area (POA-BF), a critical sleep-wake regulatory structure, contributes to this disruption. We developed a targeted viral vector designed to overexpress tumor necrosis factor-alpha (TNFα), specifically in astrocytes (AAV5-GFAP-TNFα-mCherry), and injected it into the POA of young mice to induce heightened neuroinflammation within the POA-BF. Compared to the control (treated with AAV5-GFAP-mCherry), mice with astrocytic TNFα overproduction within the POA-BF exhibited signs of increased microglia activation, indicating a heightened local inflammatory milieu. These mice also exhibited aging-like changes in sleep-wake organization and physical performance, including (a) impaired sleep-wake functions characterized by disruptions in sleep and waking during light and dark phases, respectively, and a reduced ability to compensate for sleep loss; (b) dysfunctional VLPO sleep-active neurons, indicated by fewer neurons expressing c-fos after suvorexant-induced sleep; and (c) compromised physical performance as demonstrated by a decline in grip strength. These findings suggest that inflammation-induced dysfunction of sleep- and wake-regulatory mechanisms within the POA-BF may be a critical component of sleep-wake disturbances in aging.

The association of depressive symptoms with handgrip strength and gait speed in community-dwelling older adults: data from the baseline phase of Birjand Longitudinal Aging Study

BACKGROUND

Depression is a multifaceted condition with a high prevalence and burden to society. Handgrip strength (HGS) and gait speed (GS) are indices of physical health, which is linked to mental health. Previous studies have shown heterogeneity among countries in the association of physical parameters and depression. In this study, we aimed to investigate the association of HGS and GS with depressive symptoms in older adults.

METHODS

This is a cross-sectional study analyzing data from the Birjand Longitudinal Aging Study, a cohort of community-dwelling older adults (≥ 60 years old). Depressive symptoms were assessed by the nine-item Patient Health Questionnaire. HGS was measured with a hand dynamometer in a sitting position, and GS was estimated by a 15-foot walk test at usual pace.

RESULTS

Compared to participants in the first quartile, those in the second quartile of HGS had significantly lower odds of suffering from depressive symptoms, while GS was not significantly associated with depressive symptoms. A higher HGS was associated with a lower risk of moderate depressive symptoms, while a higher GS was related to a lower risk of moderately severe and severe symptoms.

CONCLUSIONS

Our findings suggest that older people residing in Birjand, Iran with a moderate HGS are less likely to suffer from depressive symptoms than those with lower HGS.

Associations between pinch strength, cardiovascular events and all-cause mortality in patients undergoing maintenance hemodialysis

BACKGROUND AND AIMS

Patients undergoing maintenance hemodialysis (MHD) experience increased mortality and cardiovascular disease (CVD) risks; however, the potential connection between pinch strength (PS) and the prognosis of these patients remains unknown. Consequently, this study aimed to comprehensively assess the influence of PS and handgrip strength (HGS) on both survival and cardiovascular events (CVE) in patients undergoing MHD.

METHODS

Data were gathered from patients undergoing MHD at the Hemodialysis Center of Guangzhou Red Cross Hospital in March 2021. We performed a retrospective follow-up spanning 24 months, with death serving as the primary endpoint for observation and CVE as the secondary endpoint. Multifactorial Cox regression analysis, Kaplan-Meier survival curves, trend tests, and restricted cubic spline were applied to explore the association.

RESULTS

During a 24-month follow-up, data were collected from 140 patients undergoing MHD with an average age of 66.71 ± 12.61 years. Among them, 52 (37.14%) experienced mortality, whereas 36 (40.00%) had CVE without baseline CVD. Kaplan-Meier survival curves demonstrated better survival rates and reduced CVE risk for patients in the second, third, and fourth quartiles compared with those in the first quartile for PS. Adjusted analyses in different models revealed higher PS levels were independently associated with all-cause mortality (major model, model 4, HR, 0.78; 95% CI, 0.64-0.95) but not with CVE risk (unadjusted HR, 0.90; 95% CI, 0.77-1.05). Compared with lower quartile PS levels, higher PS levels significantly reduced all-cause mortality (HR, 0.31; 95% CI, 0.10-1.02), and this trend remained consistent (P for trend = 0.021). Finally, the restricted cubic spline method using different models showed a linear relationship between PS and all-cause mortality (P > 0.05), when PS exceeded 4.99 kg, the all-cause mortality of MHD patients significantly decreased.

CONCLUSIONS

PS was independently associated with all-cause mortality but not with CVE in patients undergoing MHD.

Association of Metal Exposure with Novel Immunoinflammatory Indicators

Objective: We aimed to investigate the relationship between metal exposure and novel immunoinflammatory indicators. Methods: Data on adults participating in the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018 were analyzed. Various statistical models were employed to assess the association between metal exposure and novel immune-inflammation-related indicators. Additionally, the impact of metal exposure on inflammation in different gender populations was explored. Results: This study included 4482 participants, of whom 51.1% were male. Significant correlations were observed among various metals. Both elastic net (ENET) and linear regression models revealed robust associations between cadmium (Cd), cobalt (Co), arsenic (As), mercury (Hg), and immunoinflammatory indicators. Weighted quantile sum (WQS) and Quantile g-computation (Q-gcomp) models demonstrated strong associations between barium (Ba), Co, and Hg and immunoinflammatory indicators. Bayesian kernel machine regression (BKMR) analysis indicated an overall positive correlation between in vivo urinary metal levels and systemic inflammation response index (SIRI) and aggregate index of systemic inflammation (AISI). Furthermore, Co, As, and Hg emerged as key metals contributing to changes in novel immunoinflammatory indicators. Conclusions: Metals exhibit associations with emerging immunoinflammatory indicators, and concurrent exposure to mixed metals may exacerbate the inflammatory response. Furthermore, this relationship varies across gender populations.

Predictors of elevated C-reactive protein among pre-treatment, newly diagnosed breast cancer patients: A cross-sectional study

BACKGROUND & AIMS

Accumulating evidence showed that inflammation contributes markedly to cancer progression, with C-reactive protein (CRP) being one of the lengthily studied inflammation marker. For breast cancer (BCa), pre-treatment elevated CRP upon diagnosis was linked with increased mortality. This study aimed to identify factors predictive of elevated CRP in pre-treatment BCa population that can serve as potential therapeutic targets to reduce inflammation.

METHODS

This is a cross-sectional study using multiple logistic regression to identify predictors of elevated CRP among pre-treatment, newly diagnosed BCa patients. Studied variables were socio-demographic and medical characteristics, anthropometric measurements [body weight, Body Mass Index, body fat percentage, fat mass/fat free mass ratio, muscle mass, visceral fat], biochemical parameters [albumin, hemoglobin, white blood cell (WBC), neutrophil, lymphocyte], energy-adjusted Dietary Inflammatory Index, handgrip strength (HGS), scored Patient Generated-Subjective Global Assessment, physical activity level and perceived stress scale (PSS).

RESULTS

A total of 105 participants took part in this study. Significant predictors of elevated CRP were body fat percentage (OR 1.222; 95 % CI 1.099-1.358; p < 0.001), PSS (OR 1.120; 95 % CI 1.026-1.223; p = 0.011), low vs normal HGS (OR 41.928; 95 % CI 2.155-815.728; p = 0.014), albumin (OR 0.779; 95 % CI 0.632-0.960; p = 0.019), and WBC (OR 1.418; 95% CI 1.024-1.963; p = 0.036).

CONCLUSION

Overall, predictors of elevated CRP in pre-treatment, newly diagnosed BCa population were body fat percentage, PSS, HGS category, albumin and WBC.

Understanding of and clinical approach to cardiometabolic transition at the menopause

Cardiovascular disease (CVD) represents the leading cause of death and accounts for almost 50% of all deaths in women worldwide. The menopausal transition is associated with central body fat accumulation, a decrease in energy expenditure, weight gain, insulin resistance and a pro-atherogenic lipid profile. Moreover, menopause is independently associated with an adverse effect on functional and structural indices of subclinical atherosclerosis. Women with premature ovarian insufficiency have heightened CVD risk compared to women of natural age at menopause. Furthermore, women with severe menopausal symptoms may have a more adverse cardiometabolic profile than those without symptoms. We reviewed the latest evidence on the cardiovascular management of perimenopausal or postmenopausal women. Clinicians should aim for cardiovascular risk stratification, followed by dietary and lifestyle advice as required based on individual needs. The medical management of cardiometabolic risk factors at midlife should always be individualized, focusing on hypertension, diabetes and dyslipidemia. Menopausal hormone therapy, when prescribed for the management of bothersome menopausal symptoms or for the prevention of osteoporosis, has also a beneficial effect on cardiometabolic risk factors. This narrative review aims to summarize the cardiometabolic alternations occurring during the menopausal transition and to outline the appropriate prevention strategies to prevent future cardiovascular adverse outcomes.

Gingival bleeding as a predictor of handgrip strength-an observational study and a pilot randomized clinical trial

OBJECTIVE

The aim of this study was to (i) assess the association between self-reported periodontal disease and gingival bleeding as predictors of handgrip strength (HGS) in the elderly and (ii) evaluate the impact of baseline periodontal clinical parameters on the improvement of HGS in trained or non-trained treated periodontitis patients.

METHODS

For (i), cross-sectional data from the Brazilian Longitudinal Study of Aging were retrieved and association between HGS (dependent variable) and self-reported gingival bleeding, periodontal disease, and missing teeth was analyzed using multiple linear regressions. For (ii), a pilot study was conducted with 17 patients randomly allocated to two groups-physical training or non-training-and followed for 45 days after subgingival instrumentation. Clinical parameters and HGS were recorded before and after treatment.

RESULTS

The observational study showed a significant association between HGS and tooth loss, edentulism and gingival bleeding. The clinical trial showed that baseline bleeding on probing, but not other parameters, was associated with delta HGS.

CONCLUSION

Taken together, our findings suggest that gingival bleeding could act as a predictor of handgrip strength and its improvement after non-surgical periodontal therapy.

CLINICAL RELEVANCE

Gingival bleeding, either as self-perceived or clinically detected, may impact handgrip strength, an important marker of muscle frailty and mortality.

Grip strength affects the association between platelet count and disability-free survival: Evidence from the China Health and Retirement Longitudinal Study

BACKGROUND AND AIMS

Previous studies found elevated platelet count (PLT), especially long-term persist high or increased PLT was associated with less likelihood disability-free survival (DFS). However, whether grip strength affects the relationship between them is still not elucidated.

METHODS

A total of 6252 participants were recruited in the analysis based on the China Health and Retirement Longitudinal Study. The primary outcome was DFS, evaluated by a composite endpoint based on the first occurrence of either disability (having difficulty in at least one of the 6 activities of daily living: namely, dressing, bathing, continence, eating, getting into or out of bed, and toileting) or all-cause mortality.

RESULTS

The association of PLT with primary outcome was significantly modified by grip strength (pinteraction = 0.022). The rates of primary outcome were significantly lower among participants with lower baseline PLT in participants with normal grip strength (multivariable odds ratio [OR], 0.67; 95% confidence interval [CI], 0.54-0.84; ptrend < 0.001), but not in those with low grip strength (multivariable OR, 1.70; 95% CI, 0.88-3.15; ptrend = 0.135), for the lowest quartile vs the highest quartile. Adding baseline PLT (quartiles or continuous) to a model containing conventional risk factors significantly improved risk reclassification for primary outcome among those with normal grip strength (most of p < 0.05).

CONCLUSION

An inverse dose-response association of PLT with DFS was found among participants with normal grip strength, but not among those with low grip strength. Low grip strength might weaken the benefit of low PLT on DFS among middle-aged and older Chinese.

The associations between dietary fibers intake and systemic immune and inflammatory biomarkers, a multi-cycle study of NHANES 2015-2020

Background

In recent years, there has been considerable growth in abnormal inflammatory reactions and immune system dysfunction, which are implicated in chronic inflammatory illnesses and a variety of other conditions. Dietary fibers have emerged as potential regulators of the human immune and inflammatory response. Therefore, this study aims to investigate the associations between dietary fibers intake and systemic immune and inflammatory biomarkers.

Methods

This cross-sectional study used data from the National Health and Nutrition Examination Survey (2015-2020). Dietary fibers intake was defined as the mean of two 24-h dietary recall interviews. The systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), neutrophil-to-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), red blood cell distribution width-to-albumin ratio (RA), ferritin, high-sensitivity C-reactive protein (hs-CRP), and white blood cell (WBC) count were measured to evaluate systemic immune and inflammatory states of the body. The statistical software packages R and EmpowerStats were used to examine the associations between dietary fibers intake and systemic immune and inflammatory biomarkers.

Results

Overall, 14,392 participants were included in this study. After adjusting for age, gender, race, family monthly poverty level index, alcohol consumption, smoking status, vigorous recreational activity, body mass index, hyperlipidemia, hypertension, diabetes, and dietary inflammatory index, dietary fibers intake was inversely associated with SII (β = -2.19885, 95% CI: -3.21476 to -1.18294, p = 0.000248), SIRI (β = -0.00642, 95% CI: -0.01021 to -0.00263, p = 0.001738), NLR (β = -0.00803, 95% CI: -0.01179 to -0.00427, p = 0.000284), RA (β = -0.00266, 95% CI: -0.00401 to -0.00131, p = 0.000644), ferritin (β = -0.73086, 95% CI: -1.31385 to -0.14787, p = 0.020716), hs-CRP (β = -0.04629, 95% CI: -0.0743 to -0.01829, p = 0.002119), WBC (β = -0.01624, 95% CI: -0.02685 to -0.00563, p = 0.004066), neutrophils (β = -0.01346, 95% CI: -0.01929 to -0.00764, p = 0.000064). An inverse association between dietary fibers and PLR was observed in the middle (β = -3.11979, 95% CI: -5.74119 to -0.4984, p = 0.028014) and the highest tertile (β = -4.48801, 95% CI: -7.92369 to -1.05234, p = 0.016881) and the trend test (βtrend = -2.2626, 95% CI: -3.9648 to -0.5604, Ptrend = 0.0150). The observed associations between dietary fibers intake and SII, SIRI, NLR, RA, ferritin, hs-CRP, WBC, and neutrophils remained robust and consistent in the sensitivity analysis. No significant interaction by race was found.

Conclusion

Dietary fibers intake is associated with the improvement of the parameters of the immune response and inflammatory biomarkers, supporting recommendations to increase dietary fibers intake for enhanced immune health.

Pro-Inflammatory Biomarkers Combined with Body Composition Display a Strong Association with Knee Osteoarthritis in a Community-Based Study

Knee osteoarthritis (KOA) is one of the most common progressive, age-dependent chronic degenerative joint diseases. KOA often develops as a result of a gradual articular cartilage loss caused by its wear and tear. Numerous studies suggest that the degradation of the knee joint involves inflammatory components. This process is also associated with body composition, particularly being overweight and muscle mass loss. The present study aimed to search for novel circulating KOA inflammatory biomarkers, taking into account body composition characteristics. To this aim, we recruited 98 patients diagnosed and radiologically confirmed with KOA and 519 healthy controls from the Arab community in Israel. A panel of soluble molecules, related to inflammatory, metabolic, and musculoskeletal disorders, was measured by ELISA in plasma samples, while several body composition parameters were assessed with bioimpedance analysis. Statistical analysis, including multivariable logistic regression, revealed a number of the factors significantly associated with KOA, independently of age and sex. The most significant independent associations [OR (95% CI)] were fat body mass/body weight index-1.56 (1.20-2.02), systemic immune-inflammation index-4.03 (2.23-7.27), circulating vaspin levels-1.39 (1.15-1.68), follistatin/FSTL1 ratio-1.32 (1.02-1.70), and activin A/FSTL1 ratio-1.33 (1.01-1.75). Further clinical studies are warranted to confirm the relevance of these KOA-associated biological factors. Hereafter, they could serve as reliable biomarkers for KOA in the general human population.

Emerging healthy lifestyle factors and all-cause mortality among people with metabolic syndrome and metabolic syndrome-like characteristics in NHANES

BACKGROUND

The impact of integrated lifestyles on health has attracted a lot of attention. It remains unclear whether adherence to low-risk healthy lifestyle factors is protective in individuals with metabolic syndrome and metabolic syndrome-like characteristics. We aimed to explore whether and to what extent overall lifestyle scores mitigate the risk of all-cause mortality in individuals with metabolic syndrome and metabolic syndrome-like characteristics.

METHODS

In total, 6934 participants from the 2007 to 2014 National Health and Nutrition Examination Survey (NHANES) were included. The weighted healthy lifestyle score was constructed based on smoking, alcohol consumption, physical activity, diet, sleep duration, and sedentary behavior information. Generalized linear regression models and restricted cubic splines were used to analyze the association between healthy lifestyle scores and all-cause mortality. ​ RESULTS: Compared to participants with relatively low healthy lifestyle scores, the risk ratio (RR) in the middle healthy lifestyle score group was 0.51 (RR = 0.51, 95% CI 0.30-0.88), and the high score group was 0.26 (RR = 0.26, 95% CI 0.15-0.48) in the population with metabolic syndrome. The difference in gender persists. In females, the RRs of the middle and high score groups were 0.47 (RR = 0.47, 95% CI 0.23-0.96) and 0.21 (RR = 0.21, 95% CI 0.09-0.46), respectively. In males, by contrast, the protective effect of a healthy lifestyle was more pronounced in the high score group (RR = 0.33, 95% CI 0.13-0.83) and in females, the protective effects were found to be more likely. The protective effect of a healthy lifestyle on mortality was more pronounced in those aged < 65 years. Higher lifestyle scores were associated with more prominent protective effects, regardless of the presence of one metabolic syndrome factor or a combination of several factors in 15 groups. What's more, the protective effect of an emerging healthy lifestyle was more pronounced than that of a conventional lifestyle.

CONCLUSIONS

Adherence to an emerging healthy lifestyle can reduce the risk of all-cause mortality in people with metabolic syndrome and metabolic syndrome-like characteristics; the higher the score, the more obvious the protective effect. Our study highlights lifestyle modification as a highly effective nonpharmacological approach that deserves further generalization.

Association between composite dietary antioxidant index and handgrip strength in American adults: Data from National Health and Nutrition Examination Survey (NHANES, 2011-2014)

Background

The Composite Dietary Antioxidant Index (CDAI), a composite score of multiple dietary antioxidants (including vitamin A, C, and E, selenium, zinc, and carotenoids), represents an individual’s comprehensive dietary antioxidant intake profile. CDAI was developed based on its combined effect on pro-inflammatory markers Tumor Necrosis Factor-α (TNF-α) and anti-inflammatory effects of Interleukin-1β (IL-1β), which are associated with many health outcomes, including depression, all-cause mortality, colorectal cancer, etc. Handgrip strength is used as a simple measure of muscle strength, not only is it highly correlated with overall muscle strength, but also serves as a diagnostic tool for many adverse health outcomes, including sarcopenia and frailty syndromes.

Purpose

The association between CDAI and Handgrip strength (HGS) is currently unclear. This study investigated the association between CDAI (including its components) and HGS in 6,019 American adults.

Method

The research data were selected from the 2011–2014 National Health and Nutrition Survey (NHANES), and a total of 6,019 American adults were screened and included. A weighted generalized linear regression model was used to evaluate CDAI (including its components) and HGS.

Results

(1) CDAI was significantly positively correlated with HGS (β = 0.009, 0.005∼0.013, P &lt; 0.001), and the trend test showed that compared with the lowest quartile of CDAI, the highest quartile of CDAI was positively correlated with HGS (β = 0.084, 0.042∼0.126, P = 0.002) and significant in trend test (P for trend &lt; 0.0100). Gender subgroup analysis showed that male CDAI was significantly positively correlated with HGS (β = 0.015, 0.007∼0.023, P = 0.002), and the trend test showed that compared with the lowest quartile of CDAI, the highest quartile of CDAI was positively correlated with HGS (β = 0.131, 0.049∼0.213, P = 0.006) and the trend test was significant (P for trend &lt; 0.0100). There was no correlation between female CDAI and HGS, and the trend test was not statistically significant (P &gt; 0.05). (2) The intake of dietary vitamin E, Zinc and Selenium showed a significant positive correlation with HGS (β = 0.004, 0.002∼0.007, P = 0.006; β = 0.007, 0.004∼0.009, P &lt; 0.001; β = 0.001, 0.001∼0.001, P &lt; 0.001), vitamin A, vitamin C and carotenoid were significantly associated with HGS in the Crude Model, but this significant association disappeared in the complete model with the increase of control variables. Gender subgroup analysis showed that in model 3, male dietary intake levels of vitamin E, Zinc, and Selenium were significantly positively correlated with HGS (β = 0.005, 0.002∼0.009, P = 0.011; β = 0.007, 0.004∼0.011, P = 0.001; β = 0.001, 0.001∼0.001, P = 0.004), the rest of the indicators had no significant correlation with HGS. Among the female subjects, dietary zinc intake was significantly positively correlated with HGS (β = 0.005, 0.001∼0.008, P = 0.008), and there was no significant correlation between other indicators and HGS (P &gt; 0.05).

Conclusion

There was an association between the CDAI and HGS, but there was a gender difference, and there was an association between the CDAI and HGS in male, but the association was not significant in female. Intake of the dietary antioxidants vitamin E, selenium, and zinc was associated with HGS in male, but only zinc was associated with HGS among dietary antioxidants in female.

The association between systemic immune-inflammation index and rheumatoid arthritis: evidence from NHANES 1999-2018

PURPOSE

We aimed to explore the relationship between the systemic immune-inflammation index (SII) and rheumatoid arthritis (RA) using NHANES from 1999 to 2018.

METHODS

We collected data from the NHANES database from 1999 to 2018. The SII is calculated from the counts of lymphocytes (LC), neutrophils (NC), and platelets (PC). The RA patients were derived from questionnaire data. We used weighted multivariate regression analysis and subgroup analysis to explore the relationship between SII and RA. Furthermore, the restricted cubic splines were used to explore the non-linear relationships.

RESULT

Our study included a total of 37,604 patients, of which 2642 (7.03%) had rheumatoid arthritis. After adjusting for all covariates, the multivariate logistic regression analysis showed that high SII (In-transform) levels were associated with an increased likelihood of rheumatoid arthritis (OR=1.167, 95% CI=1.025-1.328, P=0.020). The interaction test revealed no significant effect on this connection. In the restricted cubic spline regression model, the relationship between ln-SII and RA was non-linear. The cutoff value of SII for RA was 578.25. The risk of rheumatoid arthritis increases rapidly when SII exceeds the cutoff value.

CONCLUSION

In general, there is a positive correlation between SII and rheumatoid arthritis. Our study shows that SII is a novel, valuable, and convenient inflammatory marker that can be used to predict the risk of rheumatoid arthritis in US adults.

Associations of Food Insecurity with Dietary Inflammatory Potential and Risk of Low Muscle Strength

Food insecurity refers to the uncertain availability of or limited access to nutritious food. Poor diets prevalent among food insecure populations may incite an inflammatory state and subsequently negatively affect skeletal muscle metabolism. To examine the inflammatory mechanistic potential of the association between food insecurity and the risk of low muscle strength, we analyzed cross-sectional data from 8624 adults aged ≥20 years from the Korean National Health and Nutrition Examination Survey 2014-2015. Household food security status was assessed using an 18-item food security survey module. The inflammatory potential of diets was estimated by the dietary inflammation index (DII). Low muscle strength was ascertained using hand grip strength. In the multivariable-adjusted model, greater food insecurity was significantly associated with a higher DII score and risk of low muscle strength. The multivariable-adjusted mean difference (95% confidence interval) on the DII, comparing the "moderate-to-severe" food insecurity group with the "food secure" group, was 0.43 (0.06-0.80) (P-trend: <0.001) and the odds ratio (95% confidence intervals) of low muscle strength for the same comparison groups was 2.06 (1.07-3.96) (P-trend: 0.005). Our results suggest that individuals with greater food insecurity may be susceptible to diets with greater inflammatory potential, which may contribute to a loss of muscle strength.