Assessment of existing anthropometric indices for screening sarcopenic obesity in older adults

Predictive value of six anthropometric indicators for prevalence and mortality of obstructive sleep apnoea asthma and COPD using NHANES data

Obesity is linked to a greater risk of respiratory diseases. Due to limitations in body mass index (BMI), alternative anthropometric indicators have been developed to reflect body fat distribution. This study compares six anthropometric measures-BMI, waist circumference (WC), the waist-to-height ratio (WHtR), the body roundness index (BRI), the body shape index (ABSI), and the weight-adjusted waist index (WWI)-and their relationships with the prevalence and mortality of obstructive sleep apnoea (OSA), asthma, and chronic obstructive pulmonary disease (COPD) in the US population. Data from four NHANES cycles were analyzed. Multivariable logistic regression assessed the cross-sectional associations between the six anthropometric measures and disease prevalence. Mortality associations were analysed via Cox proportional hazards models, and time‒dependent ROC curve was utilised to evaluate the predictive performance of the significant marker for mortality. BMI, WC, WWI, BRI, ABSI, and WHtR were positively correlated with the prevalence of OSA, and COPD. For asthma, BMI, WC, BRI, and WHtR were positively associated with prevalence, while ABSI and WWI were negatively associated. Concerning mortality, higher WC and BMI were associated with better survival in the OSA and COPD groups, whereas elevated WWI and ABSI were linked to greater mortality risk in the participants with OSA symptoms. An increase of one standard deviation (SD) in the ABSI resulted in an 18% increase in mortality (95% CI 1.09-1.27) for the OSA population. The area under the curve (AUC) for ABSI was 0.752 for 3-year, 0.755 for 5-year, and 0.744 for 10-year mortality. Novel anthropometric indicators, including WWI, BRI, ABSI, and WHtR, show positive associations with the prevalence of OSA, and COPD, alongside traditional measures like BMI and WC. However, WWI and ABSI were more limited in their association with asthma prevalence. Longitudinal analyses revealed that traditional anthropometric indicators such as BMI and WC were negatively associated with mortality risks in the OSA and COPD, supporting the "obesity paradox." ABSI, however, emerged as a significant mortality predictor for OSA, providing a more nuanced view of central obesity's impact on mortality. However, in COPD patients, routine anthropometric measurements may not fully capture the effects of obesity.

Evaluating Anthropometric Indices for Malnutrition Assessment in Older Adults: Scoping Review

Purpose of Review

The demographic transition in both global and national populations indicates a growing trend in the older population. This burgeoning older population brings about constraints marked by the effective presence of malnutrition alongside functional and physiological changes. Conducting screenings and assessments to prevent malnutrition and enable early intervention is crucial. In epidemiological and clinical studies, these screenings and assessments are often conducted through anthropometric measurements and a range of indices derived from them, encompassing both traditional ones like BMI (Body Mass Index) and newer ones like BRI (Body Roundness Index), BAI (Body Adiposity Index), ABSI (A Body Shape Index), CI (Conicity Index), WWI (Waist adjusted Weight Index), AVI (Abdominal Volume Index), Demiquet, and Mindeks. There is a lack of scrutiny regarding studies comparing these indices based on the type of malnutrition in the older population, hence this review aims to address the gap in the literature.

Recent Findings

Analysis of existing research reveals that BRI and waist-to-height ratio serve as predictors of obesity-related body fat quantity/distribution and metabolic risks, while WWI stands out in sarcopenic obesity, and Demiquet and Mindeks are prominent indices for screening inadequate nutrition.

Summary

Choosing anthropometric indices that do not include height in the older populations can have certain advantages. However, the selection of these indices should depend on the specific variable being assessed or screened such as obesity, malnutrition, or sarcopenic obesity.

Non-linear association between weight-adjusted-waist index and obstructive sleep apnea: a cross-sectional study from the NHANES (2005-2008 to 2015-2020)

Background

The principal objective of the present investigation is to undertake an in-depth exploration of the relationship that exists between the newly introduced weight-adjusted waist index (WWI), employed as a surrogate way for corpulence, and obstructive sleep apnea (OSA).

Methods

Analysis using cross-sectional data from 11,545 NHANES participants across 2005-2008 and 2015-2020. Obesity via WWI (waist circumference over sqrt of body weight). OSA via 3 NHANES QnA items: monthly excessive sleepiness, weekly wheezing/snoring/breathing stoppage, weekly snoring. Relationships between WWI and OSA probed with weighted multivariate logistic regression and smoothed curve fitting. Also did subgroup, interaction tests and threshold effect analysis. Excluded those with incomplete WWI, OSA or hypertension data as they might have different health profiles. We excluded participants with incomplete data on WWI, OSA, or hypertation-related items, as those with missing data might have different health profiles.

Results

The study, encompassing a cohort of 11,545 participants, revealed that 5,727 individuals were diagnosed with OSA. Upon conducting fully adjusted models, A positive relevance between WWI and OSA was established, with an odds ratio of 1.57 (95% CI: 1.44, 1.71), indicating a significant relationship. Notably, participants falling within the highest quartile of WWI exhibited a markedly heightened propensity for OSA, being 2.58 times more likely to suffer from it than those in the bottom quartile [OR: 2.58 (95% CI: 2.10, 3.17)]. Rigorous subgroup analyses and interaction tests further confirmed the robustness of this positive association across various subgroups, thereby affirming the consistency of the observed relationship. Additionally, a noteworthy non-linear association and saturation phenomenon were discerned between the WWI and OSA, demarcated by an inflection point at 11.70 cm/√kg.

Conclusion

Our research has clearly shown a significant positive correlation, along with a saturation effect, between WWI and OSA in the American population. However, the cross-sectional design limits causal inference, and the exclusion of certain participants may affect the generalizability of the findings. Future longitudinal studies are needed to explore causality and address potential biases associated with participant exclusion, ultimately improving the broader applicability of the results.

Association of the weight-adjusted waist index with mortality in osteoporotic patients

INTRODUCTION

The prevalence of osteoporosis (OP) is steadily rising, leading to a higher risk of mortality. This study assessed the impact of the Weight-Adjusted Waist Index (WWI) on osteoporosis-related mortality.

MATERIALS AND METHODS

Data from NHANES 2005-2010, 2013-2014, and 2017-2018 were analyzed to evaluate the relationship between WWI and mortality in osteoporotic patients using weighted proportional hazards model and Kaplan-Meier survival analysis. A subgroup analysis was performed to ensure the stability of the findings.

RESULTS

The study included 1324 participants. The findings indicated a positive correlation between WWI and OP (OR 1.65, 95% CI 1.45-1.89). Among patients with OP, WWI showed a positive association with all-cause mortality (HR 1.28, 95% CI 1.10-1.48). There was no observed correlation between varying WWI levels and mortality due to cardiovascular disease or cancer.

CONCLUSIONS

Maintaining a lower WWI is associated with a reduced risk of all-cause mortality among individuals with OP.

The weight-adjusted-waist index predicts all-cause and cardiovascular mortality in hypertension

Background

Weight-adjusted-waist (WWI) is a novel indicator of obesity that reflects the degree of central obesity in the human body.

Objectives

The study aimed to explore the relationship between WWI and mortality in hypertensive individuals.

Methods

Cross-sectional data from the 2001-2018 National Health and Nutrition Examination Survey (NHANES) dataset were used in this study. The relationship between WWI and mortality was assessed using a weighted Cox proportional risk model; the nonlinear relationship was explored using restricted cubic splines. The robustness of the results was verified by subgroup and sensitivity analyses.

Results

A cohort of 11,556 people with a diagnosis of hypertension was included in this study. As a continuous variable, WWI was linked to higher rates of mortality from all-cause (HR = 1.23, 95% CI = 1.14, 1.33) and cardiovascular disease (CVD) (HR = 1.43, 95% CI = 1.23, 1.66) with hypertension in Model 3 adjusted for variables. Using WWI as a tertile categorical variable, individuals in the highest tertile had a 33% higher risk of all-cause death (HR = 1.33, 95% CI = 1.14, 1.56) and a 65% higher risk of CVD death (HR = 1.65, 95% CI = 1.19, 2.27) than individuals in the lowest tertile. According to the subgroup analysis, almost all groups showed a consistent positive correlation between WWI and mortality related to all-cause and CVD.

Conclusion

In adults with hypertension, there is a positive association between WWI and all-cause and CVD mortality.

Association between weight-adjusted waist index and cognitive impairment in Chinese older men: a 7-year longitudinal study

Background

Obesity, through mechanisms such as insulin resistance and systemic low-grade inflammation, can damage the central nervous system and impair cognitive function. Weight-adjusted waist index (WWI) is a novel measure of obesity that may offer more precise assessments of muscle and fat mass. This study aims to investigate the association between WWI and cognitive function in older Chinese men.

Methods

Data from the 2011-2018 China Longitudinal Health and Longevity Survey (CLHLS) were used in this study. WWI and cognitive function were examined in both linear and non-linear situations using Kaplan-Meier survival curves, multivariate Cox regression models, and restricted cubic spline (RCS) regression.

Results

This study included 1,392 older Chinese men aged 65 years and over for whom complete data were available. After controlling for all potential confounding variables, our analysis showed a statistically significant positive association between WWI and cognitive decline. Specifically, for every 1 cm/√kg increase in WWI, the risk of cognitive impairment increased by 17% (HR = 1.17, 95% CI: 1.02-1.35). Using 11.52 cm/√kg as the cutoff point for WWI, we found that High WWI was associated with a 44% increased risk of cognitive impairment compared with Low WWI (HR = 1.44, 95% CI: 1.07-1.96). RCS regression analysis confirmed a linear positive correlation between WWI and cognitive impairment.

Conclusion

Higher WWI is linked to worse cognitive performance in older Chinese men.

Weight-adjusted waist index associated with bone mineral density in rheumatoid arthritis patients: a cross-sectional study

The research examined the association between weight-adjusted waist index (WWI) and bone mineral density (BMD) in individuals with rheumatoid arthritis, considering the impact of obesity on bone health. The association between WWI and BMD was examined utilizing weighted linear regression and smoothed curve fitting with data from NHANES 2005-2010, 2013-2014, and 2017-2018. Subgroup analysis verified the stability of the results. The study included a cohort of 983 rheumatoid arthritis patients. A significant negative correlation was found between WWI and BMD at the total femur, femoral neck, and lumbar spine (β = -0.03, 95% CI (-0.04, -0.02), p < 0.001; β = -0.02, 95% CI (-0.04, -0.01), p = 0.001; β = -0.04, 95% CI (-0.06, -0.02), p < 0.001). This negative association was not significantly influenced by factors like age, gender, race, education, PIR, diabetes, hypertension, sleep disorders, alcohol consumption, or smoking status (p > 0.05 for interaction). The findings indicate a negative correlation between WWI and BMD in the rheumatoid arthritis population. Key Points •A negative correlation was found between WWI and BMD at the total femur, femoral neck, and lumbar spine in the rheumatoid arthritis population.

Weight-Adjusted Waist Index (WWI)-A Promising Anthropometric Indicator of Depressive Symptoms in Hospitalized Older Patients

OBJECTIVES

The aim of this study was to evaluate which anthropometric index, either body mass index (BMI) or weight-adjusted waist index (WWI), is more accurately associated with the prevalence of the most common chronic diseases and components of geriatric assessment in hospitalized older adults.

METHODS

The study included a total of 2945 hospitalized older adults (median age 82 years). The associations between the presence of chronic diseases and Comprehensive Geriatric Assessment (CGA) results were compared with WWI and BMI values.

RESULTS

The WWI was significantly higher in both sex groups suffering from hypertension, diabetes, osteoarthritis, and depression. In women, the parameter was increased among individuals with previous myocardial infarction, who presented heart failure symptoms or had chronic kidney disease diagnosed, whereas in men, among those with pulmonary diseases and osteoporosis, WWI was related to many CGA parameters oftentimes where BMI proved to fail. There was a positive correlation of WWI with the presence of depressive symptoms assessed with the geriatric depression scale (GDS) but no significant correlation with BMI. In multiple logistic regression models, WWI was a stronger predictor of depression as compared to waist circumference or the waist-to-height ratio.

CONCLUSIONS

There is an association between a higher WWI and depression diagnosis as well as the presence of depressive symptoms according to the GDS in hospitalized older adults, both women and men. There is no such correlation between depression and BMI. Both high BMI and high WWI values seem to identify older patients with cardiometabolic diseases such as hypertension and diabetes. According to this study, WWI seems to be a promising indicator of depression risk and, similarly to BMI, a useful parameter for the assessment of cardiometabolic risk in older hospitalized adults.

Weight-adjusted-waist index: an innovative indicator of breast cancer hazard

BACKGROUND

Central obesity and breast cancer (BC) have been identified as relevant by empirical research. The weight-adjusted-waist index (WWI) is a novel methodology for quantifying central obesity. Inspection of the association between WWI and BC in American adult women was the primary goal of the current investigation.

METHODS

Cross-sectional assessments were conducted on information gathered from 10,193 National Health and Nutrition Examination Survey (NHANES) participants from 2011 to 2018. The waist circumference was divided by the square root of the body's mass to compute WWI. Data were assessed via descriptive statistics to present data distributions according to BC grouping and WWI grouping, receiver operating characteristic curves (ROCs) to evaluate the obesity indicators' applied value, logistic regression to reflect associations between WWI and BC prevalence, and restricted cubic splines (RCSs) and subgroup analysis forest plots to visualise and complement the relationships.

RESULTS

This study enrolled 10,193 participants whose WWI ranged from 8.38 to 14.41, 259 of whom were diagnosed with BC, and the results revealed significant differences in baseline characteristics between the groups. With an area under the curve (AUC) value (95% confidence interval) (CI)of 0.611 (0.577-0.644), WWI was a promising indicator of BC with good application value rather than waist circumference (WC), body mass index (BMI), or waist-height ratio (WHtR). WWI and BC laid out a substantial relationship, yielding an odds ratio (OR) of 1.54 and a 95% CI of (1.34, 1.79), which remained at 1.19 (1.00, 1.42) after considerable adjustments were made, according to the logistic regression analysis. Compared with the lowest quartile of WWI, the highest quartile had a 62% greater in the probability of suffering from BC. With the RCS's inverted U-shape highlighting the importance of considering the nonlinear nature of the relationship and subgroup analyses reflecting variations among populations, all the results demonstrated that WWI was a well-suggestive indicator of BC hazard.

CONCLUSION

The current investigation revealed a meaningful association between the prevalence of BC and WWI, which was superior to other obesity indicators, albeit one that was more complex than the positive relationship initially derived. There existed a turning point for BC prevalence at WWI of approximately 12 cm/√kg. Nevertheless, maintaining WWI in the lower range is critical for preventing and administering BC and minimizing disease risk.

Weight-Adjusted Waist Index: an anthropometric measure for frailty in older adults

PURPOSE

Current measures of frailty often rely on subjective assessments or complex scoring systems. This study aims to investigate the utility of a novel anthropometric measure, the Weight-Adjusted Waist Index (WWI), as a simple and objective predictive marker for frailty in older adults.

METHODS

This cross-sectional study included 847 patients aged 65 years and older. Comprehensive geriatric assessments and anthropometric measurements were conducted. Frailty was diagnosed using the Clinical Frailty Scale (CFS). The association between WWI and frailty was analyzed using multivariate logistic regression analysis.

RESULTS

The mean age of the participants was 74.9 ± 6 years, with 56.3% (n = 477) being women and 14.8% (n = 125) classified as frail. The frail group had a significantly higher WWI than the non-frail group (p < 0.001). In multivariate logistic regression analysis, WWI remained significantly associated with frailty, even after adjusting for other potential confounding factors (OR = 2.51, 95% CI 1.77-3.57, p < 0.001). The predictive ability of WWI for frailty was measured by the area under the receiver operating characteristic (ROC) curve, which was 0.705 (95% CI 0.67-0.73; p < 0.001). The optimal WWI threshold for predicting frailty was identified as > 12.

CONCLUSION

The Weight-Adjusted Waist Index shows significant potential as a simple and objective predictive marker for frailty in older adults.

Correlation of insulin resistance-related indicators and obesity-related indicators with sarcopenic obesity and development of diagnostic models: NHANES 1999-2006

This study investigates the correlation between insulin resistance and obesity indicators with sarcopenic obesity (SO) and develops diagnostic models. Utilizing the 1999-2006 National Health and Nutrition Examination Survey (NHANES) database, the research included 5,574 adults. Sarcopenic obesity was defined following the 2022 consensus by ESPEN and EASO. The study analyzed indicators such as the triglyceride-glucose index (TyG), homeostasis model assessment of insulin resistance (HOMA-IR), body roundness index (BRI), and lipid accumulation product (LAP). Results indicated a significant positive correlation between these indicators and SO, with the strongest association observed for TyG-WHtR. Predictor variables were identified through logistic and Lasso regression, including age, sex, weight-height ratio (WHtR), and TyG-WCR. The diagnostic model demonstrated good predictive performance with AUC values of 0.897 for internal validation and 0.853 for external validation. The study underscores the importance of early identification of SO patients and provides a theoretical foundation for future prevention and management strategies. Limitations include the cross-sectional study design and the potential limited generalizability of the model based on the American population.

Association between Weight-Adjusted Waist Index and Depression in NAFLD: the modulating roles of sex and BMI

BACKGROUND

The Weight-Adjusted Waist Index (WWI) is a novel indicator of obesity that accurately reflects body composition. However, the association between WWI and depression in patients with non-alcoholic fatty liver disease (NAFLD) remains unclear. This study aims to explore this relationship through a nationally representative cross-sectional analysis.

METHODS

This study included adult participants diagnosed with NAFLD from NHANES 2017-2020. WWI was calculated as the waist circumference (cm) divided by the square root of body weight (kg). NAFLD diagnosis relied on vibration-controlled transient elastography (VCTE) with a controlled attenuation parameter (CAP) exceeding 248 dB/m to indicate hepatic steatosis. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), with scores ≥ 10 indicating the presence of major depression.

RESULTS

After adjusting for all covariates, a significant positive association was found between WWI and depression in NAFLD (OR = 1.725, 95% CI: 1.442-2.063, p < 0.00001), with a dose-response relationship indicated by restricted cubic spline analysis. The association was stronger in men and lean/normal weight NAFLD patients. Adjusting further for BMI did not alter these findings (OR = 1.643, 95% CI: 1.357-1.989, p < 0.00001). BMI's association with depression was negated after adjusting for WWI.

CONCLUSIONS

WWI had a positive association with depression in NAFLD, independent of BMI. This association was more pronounced in men and lean/normal weight NAFLD. These findings suggest that WWI may be a novel indicator of depression in NAFLD and potentially valuable in depression prevention.

Association Between the Weight-Adjusted Waist Index and OSA Risk: Insights from the NHANES 2017-2020 and Mendelian Randomization Analyses

Background

Obesity is a significant risk factor for obstructive sleep apnea (OSA). The weight-adjusted-waist index (WWI) reflects weight-independent centripetal obesity. Our study aims to evaluate the relationship between WWI and OSA.

Methods

The data used in the current cross-sectional investigation are from the National Health and Nutrition Examination Survey (NHANES), which was carried out between 2017 and 2020. We utilized weighted multivariable-adjusted logistic regression to evaluate the relationship between WWI and the risk of OSA. In addition, we applied various analytical methods, including subgroup analysis, smoothing curve fitting, threshold effect analysis and the receiver operating characteristic (ROC) curve. To further explore the relationship, we conducted a MR study using genome-wide association study (GWAS) summary statistics. We performed the main inverse variance weighting (IVW) method along with other supplementary MR methods. In addition, a meta-analysis was conducted to provide an overall evaluation.

Results

WWI was positively related to OSA with the full adjustment [odds ratio (OR)=1.14, 95% confidence interval (95% CI): 1.06-1.23, P<0.001]. After converting WWI to a categorical variable by quartiles (Q1-Q4), compared to Q1 the highest WWI quartile was linked to an obviously increased likelihood of OSA (OR=1.26, 95% CI: 1.06-1.50. P=0.01). Subgroup analysis revealed the stability of the independent positive relationship between WWI and OSA. Smoothing curve fitting identified a saturation effect of WWI and OSA, with an inflection point of 11.62. In addition, WWI had the strongest prediction for OSA (AUC=0.745). Sensitivity analysis was performed to verify the significantly positive connection between WWI and stricter OSA (OR=1.18, 95% CI: 1.05-1.32, P=0.005). MR meta-analysis further supported our results (OR=2.11, 95% CI: 1.94-2.30, P<0.001). Sensitivity analysis confirmed the robustness and reliability of these findings.

Conclusion

WWI was significantly associated with the risk of OSA, suggesting that WWI could potentially serve as a predictor for OSA.

Relationship between weight-adjusted waist index (WWI) and osteoarthritis: a cross-sectional study using NHANES data

This study aims to evaluate the association between the Weight-Adjusted Waist Index (WWI) and osteoarthritis (OA) utilizing cross-sectional data from the 2005-2014 National Health and Nutrition Examination Survey (NHANES). The study analyzed data from 12,696 participants across the 2005-2014 NHANES cycles to examine differences in demographic, socioeconomic, lifestyle, and health-related variables across WWI quartiles. Multivariable logistic regression models were employed to assess the relationship between WWI and the risk of OA. Receiver Operating Characteristic (ROC) curve analysis was conducted to evaluate and compare the predictive ability of WWI, BMI, waist circumference, and weight in identifying OA risk. Scatter plots were generated to visualize the association between WWI and OA, with linear regression lines illustrating trends and statistical significance. Restricted cubic spline (RCS) analysis was used to further explore the nonlinear relationship between WWI and OA risk. Forest plots were used to display the impact of WWI on OA risk across subgroups such as gender, age, and race, showing that individuals with higher WWI generally exhibit a significantly increased risk of OA. After adjusting for multiple covariates, the findings indicated a significant association between higher WWI and an increased risk of OA. Subgroup analyses, including gender, age, and race, further reinforced the consistent association between WWI and OA risk. In the U.S. adult population, an elevated WWI is significantly associated with an increased risk of OA, suggesting that WWI could serve as a potential indicator for assessing OA risk.

Gender differences in weight-adjusted waist index in elderly inhabitants of a geriatric center

INTRODUCTION AND AIM

Weight-adjusted waist index (WWI) represents a novel anthropometric measure for assessing obesity. Bearing in mind that there is insufficient data in the literature regarding gender differences in WWI values, the aim of the current study was to examine gender differences in WWI values among older adults.

Association between the weight-adjusted-waist index and testosterone deficiency in adult males: a cross-sectional study

Testosterone deficiency has been recognized as a significant health concern and is closely related to obesity. The weight-adjusted-waist index (WWI) is an innovative adiposity parameter that is superior to BMI in certain aspects, but its relationship with testosterone levels has not been elucidated. The aim of this study was to investigate the relationships of the WWI with total testosterone levels and testosterone deficiency. Data from the National Health and Nutrition Examination Survey (NHANES, 2011-2016) were utilized. The WWI was calculated as waist circumference (cm) over the square root of weight (kg), and a total testosterone level of less than 300 ng/dL was defined as testosterone deficiency. Weighted multivariable regression models were used to assess the associations. A total of 6859 participants were included, 26.28% of whom were testosterone deficient. The WWI was inversely related to total testosterone levels (β = -49.93, 95% CI: -60.07, -39.78, P < 0.001) and positively associated with testosterone deficiency (OR = 1.46, 95% CI: 1.23, 1.72, P < 0.001) in the fully adjusted model. A significant nonlinear relationship was also detected between WWI and testosterone deficiency (P for nonlinearity = 0.004) with an inflection point of 9.486 cm/√kg. The associations were consistent in the subgroup analysis (all P > 0.05), except for the participants with eGFR < 60 mL/(min*1.73m2) and hypertension. A higher WWI was linked to lower total testosterone levels and a greater risk of developing testosterone deficiency, especially among those who had an eGFR ≥ 60 mL/(min*1.73m2) and were nonhypertensive.

Weight-adjusted waist index is positively and linearly associated with all-cause and cardiovascular mortality in metabolic dysfunction-associated steatotic liver disease: findings from NHANES 1999-2018

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease. Body mass index (BMI) is the most used obesity index but has important limitations. The weight-adjusted waist index (WWI) is a novel obesity metric and accurately reflects body composition. We explored the association of WWI with all-cause and cardiovascular disease (CVD) mortality in MASLD.

METHODS

Adult participants with MASLD were included from NHANES 1999-2018. WWI was calculated by dividing the waist circumference (WC) by the square root of body weight. MASLD was diagnosed by the presence of hepatic steatosis and at least one cardiometabolic risk factor in the absence of other causes of steatosis. A fatty liver index ≥60 suggested the presence of hepatic steatosis. Mortality data was obtained by prospectively linking to the National Death Index. Multivariate Cox proportional hazards regression analyses were used to explore these associations and multiple adjustment models were constructed including crude, partial, and fully adjusted models.

RESULTS

After adjusting for all covariates including BMI, WWI remained positively and linearly associated with all-cause and CVD mortality in MASLD (hazard ratios [HR] 1.247 and 1.218, respectively). Higher WWI was associated with a significantly increased risk of mortality (both p for trend <0.05). There was an "obesity paradox" between BMI and all-cause mortality in MASLD, with significantly lower all-cause mortality in those with overweight/obesity compared to normal BMI (HR 0.625 and 0.596, respectively, p for trend = 0.024), and no association between BMI and CVD mortality. Interaction analyses indicated that these associations were influenced by several demographic variables and disease status. Time-dependent receiver operating characteristic curves indicated that the predictive value of WWI for mortality in MASLD was higher than that of BMI, WC, and waist-to-height ratio across all follow-up durations.

CONCLUSIONS

WWI was positively and linearly associated with all-cause and CVD mortality in MASLD, whereas BMI did not accurately reflect mortality risk. WWI provided the optimal predictive value for mortality compared to traditional obesity indicators. These findings emphasize the potential use of WWI as a novel obesity indicator for mortality risk assessment, stratification, and prevention in MASLD.

Association between healthy lifestyle and frailty in adults and mediating role of weight-adjusted waist index: results from NHANES

BACKGROUND

The relationship between healthy lifestyle and frailty remains unclear. Healthy weight is crucial for overall well-being, but using body mass index (BMI) to evaluate weight management is inefficient. This study clarifies the association between healthy lifestyle or its factors (non-smoking, moderate drinking, healthy weight, healthy diet, sufficeint physical activity, and non-sedentary) and frailty, and the feasibility of using the weight-adjusted waist index (WWI) reflecting central obesity as an intermediate indicator.

METHODS

This study included 4,473 participants from the 2007-2018 National Health and Nutrition Examination Survey (NHANES). Healthy lifestyle quality was assessed by summing the scores of each healthy lifestyle factor. Frailty was assessed using a 49-item frailty index (FI), categorizing participants into robust, pre-frail, and frail. Logistic regression to investigate the association between healthy lifestyle or its factors, WWI, and frailty. Smooth curve fitting and threshold effect analyses were used to elucidate the nonlinear association. Subgroup and two other sensitivity analyses were conducted to confirm the stability of the results. A causal mediation model examined the proportion of frailty mediated by WWI.

RESULTS

The study identified 13.98% of the participants as frail. Optimal healthy lifestyle and frailty were negatively associated (OR: 0.39, 95%CI: 0.27-0.58). Five healthy lifestyle factors (non-smoking, healthy weight, healthy diet, sufficient physical activity, and non-sedentary) were associated with a lower prevalence of frailty, with odds ratios (OR) ranging from 0.48 to 0.61. We also analyzed the association between a healthy lifestyle and WWI (OR: 0.32, 95%CI: 0.27-0.37), WWI and frailty (OR: 1.85, 95%CI: 1.59-2.16). A positive association between WWI and FI was observed beyond the inflection point (9.99) (OR: 0.03, 95%CI: 0.02-0.03). Subgroup and sensitivity analyses confirmed stable associations between healthy lifestyle, WWI, and frailty. WWI partially mediated the association between a healthy lifestyle and frailty (mediating ratio = 20.50-20.65%).

CONCLUSIONS

An optimal healthy lifestyle and positive healthy lifestyle factors are associated with a lower incidence of frailty. WWI may mediate the relationship between a healthy lifestyle and frailty.

The association of weight-adjusted waist index with the risk of osteoporosis in patients with type 2 diabetes: a cross-sectional study

BACKGROUND

The relationship between obesity and type 2 diabetes with bone health has always been a topic of debate. The weight-adjusted waist index has become a commonly used indicator for assessing central obesity, fat, and muscle mass. However, currently there is no research reporting the association between weight-adjusted waist index and risk of osteoporosis in populations of type 2 diabetes. Therefore, this study aims to provide new information on the association between weight-adjusted waist index and risk of osteoporosis in type 2 diabetes.

METHODS

This cross-sectional study involved 963 patients with type 2 diabetes who were admitted to the Department of Endocrinology of Cangzhou Central Hospital. Multivariate logistic regression models were used to assess the association between weight-adjusted waist index and osteoporosis. The potential nonlinear association was evaluated. The effects of interaction between subgroups were assessed using the likelihood ratio test.

RESULTS

Weight-adjusted waist index was positively associated with the risk of osteoporosis, regardless of traditional confounding factors. For each 1 unit increased in weight-adjusted waist index, the risk of osteoporosis increased by 67%. Furthermore, there was a nonlinear relationship between weight-adjusted waist index and osteoporosis. The subgroup analysis did not reveal any significant interactions.

CONCLUSIONS

Our study indicated a positive association between weight-adjusted waist index and the risk of osteoporosis in adult Chinese type 2 diabetes patients, and this relationship was nonlinear.

The association between weight-adjusted-waist index and muscle strength in adults: a population-based study

Background

The relationship between the weight-adjusted-waist index (WWI) and grip strength, a crucial marker in assessing sarcopenia, lacks clarity. We aimed to explore the relationship between WWI and muscle strength across genders.

Methods

The cross-sectional study involved adults with complete data on WWI and grip strength from the 2011-2014 National Health and Nutrition Examination Survey. WWI was derived by dividing waist circumference by the square root of weight. Weighted multivariable logistic regression and smooth curve fitting techniques were used to examine the independent association and potential non-linear relationship between WWI and grip strength. A two-piecewise linear regression model was utilized to determine the threshold effect. Additionally, subgroup analyses and interaction tests were conducted.

Results

The study encompassed 9,365 participants, including 4,661 males and 4,704 females. Multivariate logistic regression analysis revealed a negative correlation between WWI and grip strength among males (β = -11.49, 95% CI: -12.38, -10.60, p < 0.001) as well as females (β = -2.53, 95% CI: -2.98, -2.08, p < 0.001). Subgroup analysis showed that the negative correlation of WWI with grip strength remained consistent across various age groups and levels of obesity for both males and females.

Conclusion

An increase in WWI correlates with reduced muscle strength in both males and females. WWI was negatively associated not only with muscle mass but also with muscle strength. WWI may serve as an assessment tool for sarcopenia, but further large-scale studies are needed to clarify causality.

The weight-adjusted waist index and frailty: A cohort study from the China Health and Retirement Longitudinal Study

OBJECTIVES

This cohort study's aim was to assess the association between the weight-adjusted waist index (WWI) and frailty among middle-aged and elderly individuals in China.

METHODS

Seven-year complete follow-up data from 10,349 adults aged ≥45 years, initially surveyed in 2 011 in the China Health and Retirement Longitudinal Study, were analyzed, including clinical demographic characteristics, anthropometric indices, frailty scores, and relevant covariates. The WWI was calculated as waist circumference divided by the square root of the body weight. Frailty was evaluated using the Frailty Index. Relationships between the WWI and frailty were evaluated via Cox proportional hazards modeling. Receiver operating characteristic curve analyses assessed the effectiveness of obesity-related indicators in predicting frailty.

RESULTS

Over a median 84-month follow-up period, frailty occurred in 23.7% (2453/10,349) of participants. After potential confounder adjustment, the WWI positively correlated with frailty (adjusted hazard ratio: 1.14; 95% confidence interval: 1.08-1.20; p < 0.001). After WWI-stratification into quartiles based on frailty and covariate adjustment, regression analyses were conducted; the adjusted hazard ratios exhibited a significant upward trend (p < 0.001). The subgroup analyses revealed higher positive correlations between the WWI and frailty in males and those aged ≥65 years and lower correlations in those with a high school or higher educational level and in married or cohabiting individuals. The strong positive correlation was unaltered in the other subgroup analyses. The WWI outperformed all other obesity-related indicators as a frailty predictor.

CONCLUSIONS

The WWI is a dependable and innovative obesity-related predictor of frailty and could help in mitigating its development.

Association between weight-adjusted waist index and bone mineral density in adolescents

The negative effects of obesity and excess body fat on bone mineral density (BMD) have been widely reported. As opposed to waist circumference (WC) or body mass index (BMI), weight-adjusted waist index (WWI) is a superior method for assessing obesity. WWI also indicates centripetal obesity independently of the weight of the individual. An investigation of WWI and adolescents' BMD was conducted in this study. The National Health and Nutrition Examination Survey (NHANES) 2011-2018 provided the data for this cross-sectional investigation. In this study, weighted multivariate logit models were employed to assess the correlation between teenage BMD and WWI. Additionally, we conducted interaction tests and subgroup analysis. Through multivariate linear regression, we discovered that WWI was negatively linked with lumbar, trunk, and total BMD but not pelvis BMD in this study, which included 6828 subjects. We found that each unit increase in WWI resulted in a lumbar BMD decline of 0.04 g/cm2 (95%CI -0.04, -0.04), a trunk BMD decrease of 0.03 g/cm2 (95%CI -0.03, -0.02), and a total BMD decrease of 0.02 g/cm2 (95%CI -0.02, -0.02). In conclusion, in US teenagers, there were negative connections discovered between WWI and lumbar, trunk, and total BMD, but not pelvis BMD.

Association between weight-adjusted waist index and testosterone deficiency in adult American men: findings from the national health and nutrition examination survey 2013-2016

BACKGROUND

Testosterone deficiency (TD) and obesity are globally recognized health concerns, with a bidirectional causal relationship between them. And a newly discovered obesity indicator, the Weight-Adjusted-Waist Index (WWI), has been proposed, demonstrating superior adiposity identification capability compared to traditional body mass index (BMI) and waist circumference (WC) indicators. Therefore, we present the inaugural investigation into the associations of WWI with total testosterone levels and the risk of TD.

METHODS

Data restricted to the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2016 were analyzed. Only males aged > 20 years who completed body measures and underwent serum sex hormone testing were potentially eligible for analysis. Weighted multivariable linear regression and logistic regression analyses were employed to investigate the relationships between WWI and total testosterone levels, and the risk of TD, respectively. Smooth curve fittings and weighted generalized additive model (GAM) regression were conducted to examine the linear relationship among them. Additionally, subgroup analyses with interaction tests were performed to assess the stability of the results.

RESULTS

Finally, a total of 4099 participants with complete data on testosterone and WWI were included in the formal analysis. The mean age of study participants was 46.74 ± 0.35 years with a TD prevalence of 25.54%. After adjusting all potential confounders, the continuous WWI displayed a negative linear relationship with total testosterone levels (β=-61.41, 95%CI: -72.53, -50.29, P < 0.0001) and a positive linear relationship with risk of TD (OR = 1.88, 95%CI: 1.47, 2.39, P < 0.0001). When WWI was transformed into quartiles as a categorical variable, participants in Q4 exhibited lower total testosterone levels (β=-115.4, 95%CI: -142.34, -88.45, P < 0.0001) and a higher risk of TD (OR = 3.38, 95% CI: 2.10, 5.44, P < 0.001). These associations remained stable in subgroup analyses without significant interaction (all P for interaction > 0.05).

CONCLUSIONS

This investigation firstly unveiled a negative linear association between WWI and total testosterone levels, coupled with a positive linear relationship with the prevalence of TD in U.S. male adults aged 20 years and older. Further studies are needed to validate the potential utility of WWI for the early identification and timely intervention of TD.

Association between indicators of visceral lipid accumulation and infertility: a cross-sectional study based on U.S. women

BACKGROUND

Evidence on the association between visceral lipid accumulation and infertility remains limited and controversial. Therefore, the current investigation is the first investigation to unveil this correlation by utilizing novel indicators of visceral lipid accumulation.

METHODS

The present study utilized the NHANES 2013-2020 dataset. Researchers utilized multiple logistic regression, smoothed curve fitting, and subgroup analysis to investigate the associations of waist circumference (WC), metabolic score for visceral fat (METS-VF), lipid accumulation product (LAP), visceral adiposity index (VAI) with infertility. Additionally, the eXtreme Gradient Boosting (XGBoost) algorithm model was utilized to evaluate the relative importance of the factors.

RESULTS

After adjusting for potential factors that could influence the results, researchers discovered that all these four indicators of visceral lipid accumulation exhibited strong positive correlations with the probability of infertility. The subgroup analysis demonstrated that the correlations remained consistent in the majority of subgroups (P for interaction > 0.05). The results of XGBoost algorithm model indicate that METS-VF is the most meaningful factor in infertility. The ROC curve research revealed that while METS-VF had the greatest AUC values, there was no variation in the AUC value of different markers of visceral fat accumulation (P > 0.05).

CONCLUSIONS

The present investigation discovered that increased WC, METS-VF, LAP, and VAI were associated with a heightened prevalence of infertility.

The association between frailty and body composition among the elderly: Birjand Longitudinal Aging Study (BLAS)

Background

This study aims to assess the possible relationship between frailty and anthropometric indices in older adults using data from the first phase of the Birjand Longitudinal Aging Study (BLAS).

Methods

In this cross-sectional study, we assessed the association between frailty (Frailty index (FI) and Fried frailty phenotype) and body composition indices in 1364 participants aged ≥ 60 years (September 2018 to April 2019). Analysis was conducted using one-way ANOVA and ordinal logistic regression.

Results

Participants were categorized as frail (n = 164), non-frail (n = 415), and pre-frail (n = 785) based on FI. A significant positive association was observed between the frailty and body mass index (BMI) (OR: 1.04, 95% CI:1.01- 1.07), waist circumference (WC) (OR: 1.02, 95% CI: 1.01- 1.03), waist-to-hip ratio (WHR) (OR: 2.36, 95% CI 1.05- 5.27) and waist-to-height ratio (WHtR) (OR: 1.27, 95%CI: 1.09- 1.47). Body shape index, body roundness index, and body adiposity index showed no significant association with frailty. Moreover, a BMI greater than 29 kg/m2 increased the odds of frailty and prefrailty by 79% (OR = 1.79, 95%CI = 1.30- 2.46, P < 0.001).

Conclusion

Results of this study showed that the risk of frailty increases as BMI and abdominal obesity indices increase. Therefore, BMI and abdominal obesity indices (WC, WHR, and WHtR) could serve as suitable tools for evaluating frailty in the elderly. However, additional studies are needed to evaluate the utility of the newly developed anthropometric indices in older adults.

The association between weight-adjusted-waist index and sarcopenia in adults: a population-based study

This study aims to investigate the relationship between weight-adjusted-waist index (WWI), a new body index, and sarcopenia, while also assessing the potential of WWI as a tool for screening sarcopenic patients. The cross-sectional study involved adults who possessed complete data on WWI and appendicular skeletal muscle mass from the 1999-2006 and 2011-2018 National Health and Nutrition Examination Surveys. Weighted multivariate regression and logistic regression analyses were employed to explore the independent relationship between WWI and sarcopenia. The study included 26,782 participants. The results showed that WWI demonstrated a positive correlation with sarcopenia risk. In the fully adjusted model, with each 1 unit increase in WWI, the risk of developing sarcopenia rose 14.55 times higher among males (OR: 14.55, 95% CI 12.33, 17.15) and 2.86 times higher among females (OR: 2.86, 95% CI 2.59, 3.15). The optimal cutoff values of WWI for sarcopenia were 11.26 cm/√kg for males and 11.39 cm/√kg for females. Individuals with a higher WWI have an increased risk of developing sarcopenia, and a high WWI functions as a risk factor for sarcopenia. Assessing WWI could assist in identifying individuals at risk of sarcopenia.

Prevalence of sarcopenic obesity in the older non-hospitalized population: a systematic review and meta-analysis

BACKGROUND

Sarcopenic obesity emerges as a risk factor for adverse clinical outcomes in non-hospitalized older adults, including physical disabilities, metabolic diseases, and even mortality. In this systematic review and meta-analysis, we investigated the overall SO prevalence in non-hospitalized adults aged ≥ 65 years and assessed the sociodemographic, clinicobiological, and lifestyle factors related to SO.

METHODS

We searched the PubMed, Embase, Cochrane Library, and Web of Science databases for studies reporting the prevalence of SO from database inception to October 2023. Two researchers independently screened the literature, evaluated the study quality, and extracted the data. Both fixed- and random-effects models were used in the meta-analysis to estimate the pooled SO prevalence and perform subgroup analyses. Publication and sensitivity bias analyses were performed to test the robustness of the associations.

RESULTS

Among 46 studies eligible for review and a total of 71,757 non-hospitalized older adults, the combined prevalence of SO was 14% (95% CI:11-17%, I2 = 99.5%, P < 0.01). Subgroup analysis according to lifestyle factors demonstrated that the SO prevalence was 17% (95% CI: 8-29%, I2 = 99.5%, P < 0.01) in older adults without exercise habits. Regarding clinicobiological factors, older adults with a history of falls (15% [95% CI: 10-22%, I2 = 82%, P < 0.01]), two or more chronic diseases (19% [95% CI: 10-29%, I2 = 97%, P < 0.01]), functional impairment (33% [95% CI: 29-37%, I2 = 0%, P = 0.95]), cognitive impairment (35% [95% CI: 9-65%, I2 = 83%, P = 0.02]), osteoporosis (20% [95% CI: 8-35%, I2 = 96%, P < 0.01]), high fasting glucose level (17% [95% CI: 1-49%, I2 = 98%, P < 0.01]), or the use of antipsychotics (13% [95% CI: 2-28%, I2 = 0%, P = 0.32]) exhibited a higher SO prevalence.

CONCLUSION

SO prevalence is high among non-hospitalized older adults, especially those with functional and cognitive impairments. Thus, SO is a potential problem for the aging population; implementation of planned interventions in the community is needed to reduce the prevalence and adverse outcomes of SO.

The association between weight-adjusted-waist index and depression: Results from NHANES 2005-2018

OBJECTIVE

The weight-adjusted-waist index (WWI) serves as an innovative obesity measure, seemingly surpassing body mass index (BMI) and waist circumference (WC) in evaluating lean and fat mass. This study aimed to explore the relationship between WWI and depression in United States (US) adults.

METHODS

This population-based study investigated adults with comprehensive WWI and PHQ-9 (9-item Patient Health Questionnaire) data from the National Health and Nutrition Examination Survey (NHANES) 2005-2018. WWI was computed by dividing WC by the square root of body weight. Weighted multivariate logistic regression and smoothed curve fitting were employed to examine linear and non-linear associations. Additionally, subgroup analyses and interaction tests were conducted.

RESULTS

A total of 34,528 participants were enrolled with a prevalence of depression of 7.61 %. WWI was positively related to depression with the full adjustment [odds ratio (OR) = 1.21, 95 % confidence interval (95 % CI): 1.13-1.29]. After converting WWI to a categorical variable by quartiles (Q1-Q4), compared to Q1 the highest WWI quartile was linked to an obviously increased likelihood of depression (OR = 1.51, 95 % CI: 1.29-1.76). Subgroup analysis revealed the stability of the independent positive relationship between WWI and depression (all P for trend >0.05).

CONCLUSION

WWI levels were positively related to an increased likelihood of depression in US adults. Our findings indicated that WWI may serve as a simple anthropometric index to predict depression.

Sex Differences in the Association of Weight-Adjusted-Waist Index with Sarcopenic Obesity: A Cross-Sectional Study of Hemodialysis Patients

Objective: To explore the association between weight-adjusted-waist index (WWI) and sarcopenic obesity (SO) in patients with maintenance hemodialysis (MHD). Methods: A multicenter, cross-sectional study that included 3311 adult MHD patients was conducted in 20 hemodialysis (HD) centers from June 1, 2021, to August 30, 2021. Body composition was evaluated by body composition monitor based on bioimpedance spectroscopy. Hand grip strength was measured by CAMRY® dynamometer. WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). Multiple logistic regression models, spearman correlation analysis, and receiver-operating characteristic (ROC) analyses were conducted. Results: The median age of the study was 55 years, and 39.4% of patients were female. The prevalence of SO was 22.7% in the total population, and patients with SO had higher WWI. Higher WWI quartiles were independently associated with a higher risk of SO in men after adjusting for potential confounders, including age, dialysis vintage, body mass index, biochemical indicators, and various medical histories; the odds ratio (OR) of SO was highest in the fourth quartile of the WWI (OR: 4.08, 95% confidence interval: 2.65-6.27, P for trend <0.001). Age-adjusted WWI provided a better diagnostic power than WWI only for SO in men (area under the ROC curve: 0.72 vs. 0.68, P < 0.001). WWI was not associated with SO in female HD patients. Conclusion: WWI is independently associated with SO in male but not female MHD patients. This anthropometric index is simple to calculate, making it applicable in clinical practice.

Sarcopenic Obesity as a Risk Factor for Cardiovascular Disease: An Underrecognized Clinical Entity

Sarcopenic obesity (SO) is a chronic condition and an emerging health challenge, in view of the growing elderly population and the obesity epidemic. Due to a lack of awareness among treating doctors and the non-specific nauture of the associated symptoms, SO remains grossly underdiagnosed. There is no consensus yet on a standard definition or diagnostic criteria for SO, which limits the estimation of the global prevalence of this condition. It has been linked to numerous metabolic derangements, cardiovascular disease (CVD) and mortality. The treatment of SO is multimodal and requires expertise across multiple specialties. While dietary modifications and exercise regimens have shown a potential therapeutic benefit, there is currently no proven pharmacological management for SO. However, numerous drugs and the role of bariatric surgery are still under trial, and have great scope for further research. This article covers the available literature regarding the definition, diagnostic criteria, and prevalence of SO, with available evidence linking it to CVD, metabolic disease and mortality, and an overview of current directives on management.

Association between weight-adjusted-waist index and risk of cardiovascular diseases in United States adults: a cross-sectional study

BACKGROUND

As a new obesity-related index, the weight-adjusted-waist index (WWI) appears to be a good predictor of cardiovascular disease (CVD) in East Asian populations. This study aimed to validate the association between WWI and CVD in United States (US) adults and also evaluate its relationships with the prevalence of specific CVDs.

METHODS

The data were obtained from the 2009-2016 National Health and Nutrition Examination Survey. WWI was calculated as waist circumference divided by the square root of weight, and CVD was ascertained based on self-reported physician diagnoses. Multivariable logistic regression models and subgroup analyses were performed to evaluate the association between WWI and CVD.

RESULTS

A total of 21,040 participants were included. There was a positive linear relationship between WWI and the odds of CVD (P = 0.310). After adjusting for all covariates, each unit of increased WWI was associated with 48% increased risk of CVD (odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.25-1.74). Moreover, compared with the lowest quintile (< 10.3 cm/√kg), the multivariable-adjusted OR was 3.18 (95% CI: 1.80-5.59) in the highest quintile (≥ 11.8 cm/√kg). Besides, positive associations were also found between WWI and increased prevalence of congestive heart failure (OR: 1.47, 95% CI: 1.11-1.96), coronary heart disease (OR: 1.27, 95% CI: 1.01-1.60), angina (OR: 1.44, 95% CI: 1.06-1.96), heart attack (OR: 1.66, 95% CI: 1.29-2.12), and stroke (OR: 1.32, 95% CI: 1.02-1.70). Subgroup analyses showed that stronger associations between WWI and CVD were detected in participants younger than 50 years of age (P < 0.001).

CONCLUSIONS

High levels of WWI were significantly associated with an increased risk of CVD in US adults, particularly in people under 50 years of age. These findings indicate that WWI may be an intervention indicator to reduce the risk of CVD in the general adult population.

Associations between weight-adjusted waist index and bone mineral density: results of a nationwide survey

BACKGROUND

The weight-adjusted waist circumference index (WWI) is a novel obesity indicator that offers improved accuracy in assessing both muscle and fat mass compared to traditional measures. This study aimed to investigate the association between WWI and bone mineral density (BMD) in adults.

METHODS

Weighted multivariate logistic regression, subgroup analysis, interaction tests and restricted cubic spline (RCS) curves were used to explore the relationship between WWI and BMD based on data from the National Health and Nutrition Examination Survey (NHANES).

RESULTS

This study had 40,568 individuals in total. At all four measurement sites, we detected a negative linear correlation between WWI and BMD. Even when quartile factors for WWI were created, this unfavorable connection maintained. In comparison to those in the lowest quartile, those in the highest percentile of WWI showed declines in lumbar BMD of 0.08 g/cm2 and femoral neck BMD of 0.03 g/cm2, respectively. This adverse correlation, nevertheless, differed among several categories.

CONCLUSIONS

Our findings suggest an adverse correlation between WWI and BMD among US adults. Employing WWI as a tool for osteoporosis prevention in the general population may enhance interventions.

The association between weight-adjusted-waist index and total bone mineral density in adolescents: NHANES 2011-2018

Introduction

The weight-adjusted waist index (WWI) serves as an innovative obesity measure, seemingly surpassing body mass index (BMI) and waist circumference (WC) in evaluating lean and fat mass. This study aimed to explore the relationship between WWI and total bone mineral density (BMD) in US adolescents.

Methods

This population-based study investigated adolescents aged 8-19 years with comprehensive WWI and total BMD data from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. WWI was computed by dividing WC by the square root of body weight. Weighted multivariate linear regression and smoothed curve fitting were employed to examine linear and non-linear associations. Threshold effects were determined using a two-part linear regression model. Additionally, subgroup analyses and interaction tests were conducted.

Results

Multivariate linear regression analysis revealed a significant negative association between WWI and total BMD in 6,923 US adolescents aged 8-19 years [β = -0.03, 95% CI: (-0.03, -0.03)]. This negative correlation remained consistent across all subcategories, with the exception of age, encompassing gender,ethnicity, and diabetes status subgroups. Furthermore, a non-linear relationship and saturation effect between WWI and total BMD were identified, with an inflection point at 9.88 cm/√kg.

Conclusions

Our research demonstrated a notable negative relationship and saturation effect between WWI and total BMD among US adolescents.