Association between the weight-adjusted-waist index and abdominal aortic calcification in United States adults: Results from the national health and nutrition examination survey 2013–2014

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.

Relationship between weight-to-waist index and post-stroke depression

BACKGROUND

The weight-to-waist index (WWI) serves as an innovative metric specifically designed to assess central obesity. However, the relationship between WWI and the prevalence of post-stroke depression (PSD) remains inadequately explored in the literature.

AIM

To elucidate the relationship between WWI and PSD.

METHODS

Data from the National Health and Nutrition Examination Survey 2005 to 2018 were analyzed. Multivariable logistic regression models and propensity score matching were utilized to investigate the association between WWI and PSD, with adjustments for potential confounders. The restricted cubic spline statistical method was applied to explore non-linear associations.

RESULTS

Participants with elevated WWI values had a significantly greater risk of developing PSD. Specifically, individuals in the higher WWI range exhibited more than twice the likelihood of developing PSD compared to those with lower WWI values (odds ratio = 2.21, 95% confidence interval: 1.84-2.66, P < 0.0001). After propensity score matching, the risk of PSD remained significantly elevated (odds ratio = 1.43, 95%confidence interval: 1.09-1.88, P = 0.01). Tertile analysis revealed that participants in the highest WWI tertile faced a significantly higher risk of PSD compared to those in the lowest tertile. Restricted cubic spline analysis further revealed a non-linear association, with the risk of PSD plateauing at higher WWI values.

CONCLUSION

There is a significant association between elevated WWI and increased risk of PSD. Thus, regular depression screening should be implemented in stroke patients with elevated WWI to enhance patient outcomes.

Weight-adjusted waist circumference index with hepatic steatosis and fibrosis in adult females: a cross-sectional, nationally representative study (NHANES 2017-2020)

BACKGROUND

Obesity is detrimental to liver health. Weight-adjusted waist circumference (WWI) is a new indicator of obesity that is superior to body mass index (BMI) and waist circumference (WC) in predicting obesity. There are limited studies on the relationship between Metabolic Associated Fatty Liver Disease (MASLD) and WWI. Therefore, this study aimed to investigate the association between WWI, Controlled Attenuation Parameters (CAP), and Liver Stiffness Measurement (LSM), with special attention to gender differences.

METHODS

This cross-sectional study included participants from the 2017 to 2020 National Health and Nutrition Examination Survey (NHANES). The study used multiple linear regression models, smoothed curves, and threshold effects analyses to describe the relationships between variables. Multiple regression analyses were used to examine the associations between the four obesity indicators and CAP and LSM. Subject work characteristics (ROC) curves were used to assess the predictive value of WWI and other traditional obesity indicators for hepatic steatosis and liver fibrosis, and predictive power was assessed by area under the curve (AUC).

RESULTS

The study involved 6713 participants, including 3072 men (46%) and 3641 women (54%). The results showed that among female participants, higher WWI was associated with hepatic steatosis (OR = 1.71, 95% CI: 1.43, 2.04; P < 0.0001) and hepatic fibrosis (OR = 2.11, 95% CI: 1.58, 2.84; P < 0.0001). Smoothed curve fitting of WWI versus CAP showed a statistically significant positive correlation between WWI in male and female participants There was a statistically significant positive correlation with CAP for both male and female participants. The same significant non-linear relationship was found between WWI and LSM, with no significant difference between males and females. WWI was also a good predictor of hepatic steatosis compared to other obesity indicators and was more pronounced in male participants (AUC = 0.8224). Whereas in the comparison of WWI with LSM, wBMI was a better predictor in female participants (AUC = 0.7751).

CONCLUSIONS

Based on this study, WWI was significantly associated with the risk of hepatic steatosis and hepatic fibrosis in women, suggesting the potential of WWI as a screening tool. Due to the cross-sectional design, causality cannot be inferred. Longitudinal studies are needed to validate our findings.

The relationship between weight-adjusted waist index and peripheral artery disease

Background

Obesity is a significant risk factor for peripheral arterial disease (PAD). The weight-adjusted waist index (WWI) is a novel obesity metric that better reflects abdominal obesity than traditional body mass index (BMI). However, research on the relationship between WWI and PAD remains scarce.

Methods

Relevant data from the NHANES 1999-2004 were selected. Multiple logistic regression and restricted cubic spline (RCS) analyses were used to assess the relationship between WWI and the risk of PAD. Additionally, the area under the curve (AUC) of the receiver operating characteristic (ROC) was used to evaluate the predictive ability of WWI for PAD.

Results

A total of 5,686 participants were included in the study, of whom 476 had PAD and 5,210 did not. The results of multiple logistic regression showed that WWI was significantly positively associated with the risk of PAD after full adjustment for covariates (OR: 1.407, 95% CI: 1.100-1.799). Additionally, compared to the first quartile of WWI, the risk of PAD significantly increased in the second quartile (OR: 2.042, 95% CI: 1.333-3.129), third quartile (OR: 2.134, 95% CI: 1.354-3.364), and fourth quartile (OR: 2.491, 95% CI: 1.435-4.325). The ROC results showed that the AUC value for WWI was 0.697, while the AUC value for BMI was 0.520. Compared to BMI, WWI has a better predictive value for the risk of PAD.

Conclusion

There is a significant positive correlation between WWI and the risk of PAD. For individuals with high WWI, efforts should be made to reduce WWI to prevent the onset of PAD.

Association between weight-adjusted-waist index and long-term prognostic outcomes in cardiovascular disease patients: results from the NHANES 1999-2018 study

BACKGROUND

As cardiovascular disease (CVD) morbidity and mortality increase yearly, this study aimed to explore the potential of the weight-adjusted-waist index (WWI) and its relation to long-term mortality in patients with CVD.

METHODS

The diagnosis of CVD was based on standardized medical condition questionnaires that incorporated participants' self-reported physician diagnoses. WWI (cm/√kg) is a continuous variable and calculated as waist circumference (WC, cm) divided by square root of body weight (kg). For analysis purposes, the participants were divided into four groups based on the quartiles (Q1 - Q4) of the WWI. The study's primary outcome was all-cause mortality in patients with CVD, with cardiovascular mortality as the secondary outcome, and sample weights and complex survey designs were used to ensure reliable, accurate results.

RESULTS

The final analysis included 4,445 study participants. In the fully adjusted model, the highest quartile (WWI > 12.05 cm/√ kg) showed a higher all-cause mortality rate compared with the lowest quartile (WWI < 11.03 cm/√ kg) (HR = 1.37, 95% CI: 1.03, 1.82, P < 0.05). The risk of all-cause mortality increased with WWI and showed a linear association in patients with congestive heart failure, heart attack (P-overall < 0.05, P - nonlinear > 0.05); WWI was nonlinearly associated with the risk of all-cause mortality in patients with coronary heart disease and angina (P-overall < 0.05, P - nonlinear < 0.05). Survival curve analysis further showed that all cause and cardiovascular mortality were higher in the high WWI group (Q4) (P < 0.001). The time-dependent receiver operating characteristic (ROC) curve showed that WWI's area under the curves (AUC) for 5- and 10-year survival rates were 0.76 and 0.792 for all-cause mortality and 0.734 and 0.757 for CVD mortality. WWI's AUC were higher than those of body mass index (BMI) and WC (all P < 0.01).

CONCLUSION

Our findings indicate that a high WWI is positively associated with an increased risk of all-cause mortality. Additionally, the high AUC values for WWI strengthen its potential as a meaningful prognostic marker, underscoring its utility in clinical practice for assessing long-term survival risk in patients with CVD.

Correlation between weight-adjusted waist index and coronary heart disease: NHANES 1999-2020

Background

The weight adjusted waist index (WWI) represents a novel indicator for assessing central obesity. The objective of this study is to investigate the association between WWI and coronary heart disease (CHD).

Method

The data of 44,528 participants in total were gathered from NHANES database from 1999 to 2020. WWI is calculated as the waist circumference (WC, cm) divided by the square root of the body weight (kg), and CHD was determined based on participants' self-reports. The association between WWI and CHD was examined using multiple logistic regression analysis, restrictive cubic spline (RCS), receiver operating characteristic (ROC) curve, mediation analysis, subgroup and interaction analyses.

Result

This was a cross-sectional investigation. A total of 44,528 participants were included [50.23% male; mean WWI 10.89 (0.01) cm/√kg]. The multivariate logistic regression analysis revealed that in three models, one-standard-deviation increment in WWI was associated with an increased probability of CHD occurrence by 2.39 (2.22,2.57),1.47 (1.32,1.65), and 1.15 (1.00,1.32) times, respectively. Additionally, RCS analysis indicated a linear relationship between WWI and CHD. and the ROC analysis results showed that the discriminatory power of WWI for CHD was superior to that of body mass index (BMI) and WC. Glycated hemoglobin (HbA1c) partially mediated the relationship between WWI and CHD. Subgroup and interaction analyses confirmed that age, systolic blood pressure, and diabetes status had a significant impact on the association between WWI and CHD (P for interaction <0.05).

Conclusion

The level of WWI has been demonstrated to be associated with an increased risk of CHD. Specifically, as WWI increases, the risk of CHD becomes higher. On this basis, it is hypothesized that WWI may potentially serve as an independent risk factor for CAD, thereby highlighting the substantial value of WWI in the identification and management of CHD.

Correlation of the weight-adjusted waist circumference index with Klotho in the United States: differences by sex

The relationship between the weight-adjusted waist circumference index (WWI) and the senescence-inhibitory protein Klotho remains unknown. Therefore, this study aimed to investigate the relationship between WWI and soluble Klotho (s-Klotho). This study analyzed 9,928 participants based on the 2007-2016 National Health and Nutrition Examination Survey (NHANES). Three multiple linear regression models and a restricted cubic spline (RCS) were constructed to assess the association between WWI and s-Klotho levels. Further stratified analyses and interaction tests were performed to evaluate the stability of this association. Piecewise multivariate regression modeling was applied to detect threshold effects. The fully adjusted model showed a negative correlation between continuous WWI and s-Klotho levels (β = -23.65, 95% CI: -36.55, -10.76, P < 0.001). When WWI was grouped into quartiles, participants in the highest quartile had significantly lower circulating s-Klotho levels than those in the lowest quartile (β = -40.65, 95% CI: -64.20, -17.10, P = 0.001). The RCS curves showed a linear negative correlation between WWI and s-Klotho. Further stratified analyses showed that the correlation between WWI and s-Klotho remained stable in most conditions, except for gender. A nonlinear relationship and saturation effect were observed between WWI and s-Klotho in females, with an inflection point of 11.38 cm/√kg (P for overall < 0.001; P for non-linearity = 0.013). However, no significant correlation was observed in males. There is a significant negative correlation between WWI and s-Klotho levels. Proper management of central obesity in middle-aged and older women may be beneficial in delaying senescence.

Weight-adjusted waist index and cardiovascular disease: a population-based study in Ravansar, Iran

BACKGROUND

The weight-adjusted-waist index (WWI) is a relatively new index to obesity. This study aimed to explore the reationship between WWI and cardiovascular disease (CVD).

METHODS

This cross-sectional study included 8,899 participants aged 35 to 65 from the Ravansar non-communicable diseases (RaNCD) cohort study in Ravansar, Iran. The WWI was calculated by dividing waist circumference (WC) by the square root of weight. The receiver operating characteristic (ROC) curve was utilized to assess the predictive performance of WWI in relation to CVD. The study applied multiple logistic regression to assess the association between WWI and CVD.

RESULTS

Participants had an average age of 47.52 ± 8.29 years, with 45.30% being men and 41.13% residing in rural areas. The prevalence of CVD was found to be 17.36%. A positive correlation between WWI and CVD was obseved, with individuals in the highest WWI quartile having a 36% (OR = 1.36, 95%CI: 1.11, 1.78) greater odds of CVD compared to those in the lowest quartile (OR = 1.03, 95%CI: 0.79, 1.33) (ptrend = 0.010). Subgroup analyses indicated stronger links between WWI and CVD among participants over 50, males, urban residents, those of high socioeconomic status (SES), and passive smokers (p < 0.001). The ROC analysis revealed that WWI is a greater ability in predicting CVD (AUC: 0.64, 95%CI: 0.61, 0.64) compared to body mass index (BMI) (AUC: 0.60, 95%CI: 0.58, 0.61) and WC (AUC: 0.61, 95%CI: 0.59, 0.62).

CONCLUSION

The increase in WWI elevates the odds of CVD, making the management of WWI crucial for CVD prevention.

Association of weight-adjusted waist index with all-cause and cause-specific mortality among cancer survivors: a cohort study of the NHANES 1999-2018

Background

Obesity is becoming more widely acknowledged as a chronic illness that raises the risk of oncogenesis. This inquiry aimed to look into the correlation between cancer patient mortality and obesity, as measured by the weight-adjusted waist index (WWI).

Methods

We used continuous data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 as the benchmark, with a follow-up validity period of December 31, 2019. First, we assessed the correlation between WWI and the all-cause and cause-specific execution of cancer sufferers using multivariable Cox proportional hazards models. Second, a smoothed curve fit was utilized to examine the relationship between WWI and both cause-specific and all-cause mortality in cancer patients. Lastly, we analyzed the relationship between WWI and both cause-specific and all-cause mortality in cancer patients, to find out if this link held across the population subgroup evaluation and impact analyses were used as well during the last step.

Results

With a median follow-up of 87.8 months, 1,547 (34.7%) of the 4,463 cancer patients had deceased. Among them, 508 (11.4%) succumbed to cancer, while 322 (7.2%) passed away due to cardiovascular disease. Multivariate Cox proportional hazards model of mortality among cancer patients revealed an all-cause mortality hazard ratio [HR=1.13; 95% CI (1.04, 1.23)] and cardiovascular mortality [HR=1.39; 95% CI (1.16, 1.67)]. Furthermore, for each unit increase in WWI, all-cause mortality was significantly higher in male cancer survivors than in female cancer survivors.

Conclusions

Our study reveals substantial correlations between WWI and all-cause and cardiovascular mortality in US cancer survivors, helping to identify cancer survivors at higher risk of death and thus potentially guiding targeted interventions.

Associations between the waist-to-height ratio index and migraine: A cross-section study of the NHANES 1999-2004

BACKGROUND

The importance of obesity as a factor that increases the probability of migraine episodes is increasingly acknowledged. Thus, this study aimed to explore the potential correlation between central obesity and migraine, emphasizing the waist-to-height ratio (WHtR) as a key measure in assessing this relationship.

METHODS

This cross-sectional analysis included 13,344 individuals who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999-2004. To investigate the association associations between WHtR and migraine, we utilized refined multivariate logistic regression models, smoothing curve fitting methods, subpopulation analysis, and interactive testing.

RESULTS

Of the 13,344 participants, 2,764 (20.72%) had migraines. A significant positive correlation was observed between the WHtR and migraine incidence in both the partially adjusted model (3.08 [95% CI: 1.92-4.94]) and the crude model (1.95 [95% CI: 1.23-3.08]). The participants in the highest quartile of the WHtR had a 13% greater incidence of migraine than those in the lowest quartile [1.13(0.99,1.28)]. The interaction analysis revealed a statistically significant difference (p<0.01) in this relationship among the subgroups. Notably, the correlation between WHtR and migraine risk was not significant and negative in patients ≥60 years, indicating that obesity has a mitigating role in preventing migraine in this elderly population.

CONCLUSIONS

The incidence of migraine increased concomitantly with increased WHtR. However, central obesity has a protective effect against migraine occurrence in individuals ≥60 years. Thus, our findings underscore the importance of WHtR in migraine prevention and management strategies and highlight its potential as a critical biomarker for mitigating migraine incidence.

Association of weight-adjusted-waist index with all-cause and cardiovascular mortality in individuals with diabetes or prediabetes: a cohort study from NHANES 2005-2018

Weight-adjusted waist index (WWI) is a new marker of central obesity. This study explored the association of WWI with all-cause and cardiovascular disease (CVD) mortality in individuals with diabetes or prediabetes. 6551 participants with diabetes or prediabetes from the National Health and Nutrition Examination Survey (NHANES) records between 2005 and 2018 were included. The association of WWI with all-cause and CVD mortality was assessed using Kaplan-Meier survival analysis, Cox proportional hazards model (Cox regression), and restricted cubic spline (RCS). The predictive value of WWI for mortality was analyzed using time-dependent receiver operating characteristic curves (ROC). There were 1083 all-cause deaths and 360 CVD deaths. Multivariable-adjusted Cox regression analyses showed WWI was positively correlated with the risk of all-cause and CVD mortality in subjects with diabetes or prediabetes. Multivariate-adjusted RCS analyses showed a linear and positive correlation of WWI with all-cause mortality risk, and a nonlinear relationship with CVD mortality, with a threshold of 12.35. The area under the curve (AUC) for 3, 5, and 10-years survival for all-cause mortality was 0.795, 0.792, and 0.812, respectively, and for CVD mortality was 0.815, 0.833, and 0.831, respectively. WWI is a valuable predictor of all-cause mortality risk in patients with diabetes and prediabetes, and a valuable predictor of CVD mortality risk when patients with diabetes and prediabetes are considered as a whole.

Weight-adjusted waist index and disability: a cohort study from CHARLS

BACKGROUND

The association between weight-adjusted waist index (WWI) and disability is unclear. This study aimed to assess the relationship between WWI and disability in middle-aged and elderly Chinese individuals and provide more predictive indicators for disability prevention.

METHODS

In this study, 13,015 middle-aged and older adults aged 45 years and above who were surveyed in 2011 by the China Health and Aging Tracking Survey (CHARLS) database were selected, and 8344 respondents with complete data were included for cohort analysis after seven years of follow-up. Information on clinical demographic characteristics, anthropometric indices, assessment of disability, and related covariates were collected, and the presence or absence of disability was assessed by the disability scale. WWI was calculated by dividing the waist circumference (cm) by the square root of the body weight (kg). Cox proportional hazards model was used to analyze the association between WWI and disability after follow-up.

RESULTS

Our study found that 2912 of 8344 participants had disability after seven years of follow-up, and disability incidence was approximately 34.9%. Age, sex, place of residence, chronic disease, depression, waist circumference, and WWI were significantly associated with disability in univariate analysis. Among them, there was a positive association between WWI as a continuous variable and incidence of disability (hazard ratio (HR) = 1.26, 95% CI: 1.22-1.31, p < 0.001). WWI was transformed into categorical variables using quartiles as cutoffs for disability regression analysis. After adjusting covariates, HR values in the 2nd, 3rd and 4th quantile showed an increasing trend compared with the 1st quantile, and the risk of disability among WWI subjects in the 4th quantile increased by 43% (95% CI: 1.24-1.64). P values for the trend test in the model were all < 0.001. In subgroup analyses, the positive association between WWI and risk of disability remained robust for sex, age, alcohol consumption, smoking status, education level, marital status, and place of residence after adjusting for all covariates considered in this study.

CONCLUSIONS

WWI is a new and reliable obesity-related indicator that can be used for disability prevention. WWI can be detected and controlled for reducing the risk of disability.

Association between weight-adjusted-waist index and gynecologic cancers: a population-based study

Objective

This study aims to analyze the association between the weight-adjusted waist index (WWI) and the risk of gynecologic cancers, using data collected from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016.

Methods

We employed multiple logistic regression analysis to investigate the relationship between WWI and risk of gynecologic cancers. Subsequent subgroup analyses were performed on specific populations of interest. A restricted cubic spline model was used to explore potential non-linear relationships. Additionally, the effectiveness of WWI in predicting sarcopenia was assessed through Receiver Operating Characteristic (ROC) curve analysis. K-fold cross-validation was applied for model assessment.

Results

Among the 4,144 participants, 98 self-reported having gynecologic cancers. In the fully adjusted model, WWI was significantly associated with the prevalence of gynecologic cancers (OR = 1.38, 95% CI: 1.02-1.88, p = 0.0344). Our findings indicate a linear positive association between WWI and the risk of gynecologic cancers. Subgroup analysis revealed that WWI had the strongest association with cervical cancer (OR = 1.46, 95% CI: 0.97-2.18, p = 0.0354) and endometrial cancer (OR = 1.39, 95% CI: 0.81-2.39, p = 0.0142). No significant association was found between WWI and the risk of ovarian cancer (OR = 1.16, 95% CI: 0.48-2.72, p = 0.5359). Restricted cubic spline analysis confirmed a linear relationship between WWI and the risk of cervical, endometrial, and ovarian cancers. ROC curve analysis demonstrated that WWI had superior predictive capability for gynecologic cancers.

Conclusion

Elevated levels of WWI were significantly associated with an increased risk of gynecologic cancers in American women, displaying a stronger association than other obesity markers. Therefore, WWI may serve as a distinct and valuable biomarker for assessing the risk of gynecologic cancers, particularly cervical and endometrial cancers.

Association of the weight-adjusted waist index with hypertension in the context of predictive, preventive, and personalized medicine

Objective

Hypertension (HTN) is a prevalent global health concern. From the standpoint of preventive and personalized medicine (PPPM/3PM), early detection of HTN offers a crucial opportunity for targeted prevention and personalized treatment. This study aimed to evaluate the association between the weight-adjusted waist index (WWI) and HTN risk.

Methods

A case-control study using data from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018 was conducted. Logistic regression models assessed the association between WWI and HTN. Subgroup analyses explored differences in age, sex, ethnicity, and diabetes status. Restricted cubic spline (RCS) analyses examined potential nonlinear relationships.

Results

A total of 32,116 participants, with an average age of 49.28 ± 17.56 years, were included in the study. A significant positive association between WWI and the risk of HTN was identified (odds ratio [OR], 2.49; 95% CI, 2.39-2.59; P < 0.001). When WWI was categorized into quartiles (Q1-Q4), the highest quartile (Q4) exhibited a stronger association compared to Q1 (OR, 2.94; 95% CI, 2.65-3.27; P < 0.001). Subgroup analyses indicated that WWI was a risk factor for HTN across different populations, although variations in the magnitude of effect were observed. Furthermore, the findings from the RCS elucidated a nonlinear positive correlation between WWI and HTN.

Conclusion

WWI is independently associated with HTN risk, highlighting its potential as a risk assessment tool in clinical practice. Incorporating WWI into early detection strategies enhances targeted prevention and personalized management of HTN.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00375-3.

The essential role of dual-energy x-ray absorptiometry in the prediction of subclinical cardiovascular disease

Subclinical cardiovascular disease (Sub-CVD) is an early stage of cardiovascular disease and is often asymptomatic. Risk factors, including hypertension, diabetes, obesity, and lifestyle, significantly affect Sub-CVD. Progress in imaging technology has facilitated the timely identification of disease phenotypes and risk categorization. The critical function of dual-energy x-ray absorptiometry (DXA) in predicting Sub-CVD was the subject of this research. Initially used to evaluate bone mineral density, DXA has now evolved into an indispensable tool for assessing body composition, which is a pivotal determinant in estimating cardiovascular risk. DXA offers precise measurements of body fat, lean muscle mass, bone density, and abdominal aortic calcification, rendering it an essential tool for Sub-CVD evaluation. This study examined the efficacy of DXA in integrating various risk factors into a comprehensive assessment and how the application of machine learning could enhance the early discovery and control of cardiovascular risks. DXA exhibits distinct advantages and constraints compared to alternative imaging modalities such as ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography. This review advocates DXA incorporation into cardiovascular health assessments, emphasizing its crucial role in the early identification and management of Sub-CVD.

Correlation of weight-adjusted waist index with diabetic retinopathy in US adults aged ≥ 40 years: the NHANES 2005-2008

The effect of obesity on diabetic retinopathy (DR) has been under scrutiny in recent years. The weight-adjusted waist index (WWI) has been reported to better assess the degree of centripetal obesity in humans, with a higher WWI indicating a higher amount of body fat. The present study is the first to investigate the relationship between WWI and DR and to assess the difference in the predictive ability of WWI and other obesity indices for DR. This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2008. Researchers collected complete anthropometric data (weight and waist circumference), dilated fundus images, and adult baseline information. Independent interactions between WWI and DR were investigated using multivariate regression and subgroup analyses. In addition, nonlinear associations and threshold effects between WWI and DR were searched for by smoothed curve fitting and by two-stage linear regression modeling. Finally, the receiver operating characteristic curve (ROC) was plotted to compare the predictive power of WWI with other indices of obesity for DR. A total of 1228 eligible patients with diabetes were collected in this study. There were 631 (51.38%) males and 597 (48.62%) females. Among them, 545 (44.38%) were without diabetic retinopathy, 555 (45.20%) had mild diabetic retinopathy, 100 (8.14%) had moderate/severe diabetic retinopathy and 28 (2.28%) had proliferative diabetic retinopathy (PDR). In the fully adjusted model, each unit increase in WWI was associated with a corresponding 31% reduction in the prevalence of DR [OR (95% CI) = 0.69 (0.58, 0.83)]. Compared with subjects in the lowest quartile (quartile 1), subjects in the highest quartile of WWI levels (quartile 4) were 45% less likely to have DR [OR (95% CI) = 0.55 (0.38, 0.78)]. In the case of female participants, a U-shaped correlation was observed between WWI and DR with an inflection point of 11.49. WWI also possesses a better predictive ability for DR compared to obesity indicators such as weight, BMI, and ABSI. This study showed a negative association between WWI and DR in the U.S. population aged 40 years and older.

The association between weight-adjusted waist circumference index and cardiovascular disease and mortality in patients with diabetes

Cardiovascular disease (CVD) is a significant health concern, particularly among patients with diabetes. The weight-adjusted waist circumference index (WWI), a novel metric that accounts for central obesity, has shown potential in predicting obesity-related health risks. This study aimed to evaluate the association of WWI with CVD and mortality in patients with diabetes. Utilizing data from the National Health and Nutrition Examination Survey from 1999 to 2020, WWI was calculated by dividing waist circumference (WC) by the square root of body weight. Multivariate logistic regression, multivariate Cox regression and restricted cubic spline curves were used to assess the association between WWI and the prevalence of CVD and mortality in patients with diabetes, subgroup and sensitivity analyses were carried out to delve into the stability of the findings. The predictive performance of WWI was evaluated using the area under the receiver operating characteristic curve (ROC). This study included 8,005 individuals with diabetes. With the increase in WWI values, the risk of developing CVD and the likelihood of mortality progressively rise. The fully adjusted continuous model indicated a 28% higher chance of developing CVD and a 25% higher risk of all-cause mortality for each one-unit increase in WWI. When using the lowest quartile of WWI as the reference category, the highest quartile was linked to an increased risk of CVD (OR 1.66; 95% CI 1.10-2.50, p = 0.015) and all-cause mortality (HR 1.53, 95% CI 1.27-1.83, p < 0.001) among patients with diabetes. Subgroup and sensitivity analyses confirmed that these associations were consistent and stable in most different demographics. The ROC analysis indicated that WWI had a higher predictive capacity for CVD and all-cause mortality than WC, waist to hip ratio, and weight to height ratio. The WWI was significantly associated with the prevalence of CVD and all-cause mortality among patients with diabetes in the United States and may serve as a useful tool for identifying individuals at risk.

Association of weight-adjusted waist index with cardiovascular disease and mortality among metabolic syndrome population

Metabolic syndrome (MetS) is prevalent and significantly impacts global public health, with obesity being a major risk factor for cardiovascular diseases (CVD) and mortality. Traditional metrics like body mass index (BMI) have limitations in assessing obesity-related risks. The weight-adjusted waist circumference index (WWI) has emerged as a novel obesity metric, this study aimed to evaluate the association of WWI with CVD and mortality in MetS patients. This study used data from 12,641 participants with MetS, derived from the National Health and Nutrition Examination Survey (NHANES) conducted from 1999 to 2020. The WWI was calculated, and its association with CVD and mortality was assessed using multivariate logistic and Cox regression models. The study controlled for potential confounders and performed subgroup and sensitivity analyses to validate the robustness of the findings. The predictive performance of WWI was evaluated using the area under the receiver operating characteristic curve (ROC). Kaplan-Meier (KM) curves further were used to evaluate the associations between WWI and mortality of the MetS population. As WWI values escalated, there was a proportional rise in the risk of CVD and mortality in MetS. The fully adjusted continuous model revealed a 32.0% elevated likelihood of CVD development, a 69.5% increased probability of heart failure (HF), a 51.1% heightened risk for CVD mortality, and a 22.8% augmented risk for all-cause mortality with each one-unit increment in WWI. Comparing the highest to the lowest quartile of WWI, the top quartile exhibited a significantly increased risk of CVD (odds ratio [OR] = 1.883; 95% confidence interval [CI]: 1.276-2.633, p-value = 0.001), HF (OR = 2.909; 95% CI: 1.490-5.677, p-value = 0.002), CVD mortality (hazard ratio [HR] = 2.088; 95% CI: 1.279-3.409, p-value = 0.003), and all-cause mortality (HR = 1.394; 95% CI: 1.070-1.816, p-value = 0.014) among individuals with MetS. Sensitivity and subgroup analyses substantiated the consistency and stability of these associations across various demographic groups. The ROC analysis demonstrated that WWI outperforms BMI in predicting adverse outcomes in MetS. The KM curves validated that higher WWI values was correlated with diminished survival rates in MetS population. The WWI served as a significant indicator for assessing the risk of CVD and mortality in the MetS population. This study recommended the regular assessment of WWI in MetS individuals for evaluating their risk of CVD and mortality, potentially enhancing preventive and treatment strategies for this patient population.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Association between weight-adjusted-waist index and depression in US adults: A cross-sectional study

BACKGROUND

Current evidence implicates a significant association between depression and obesity and related metabolic dysfunction. The weight-adjusted-waist index (WWI) was recently identified as an ideal index that integrates total body fat, muscle mass, and bone mass. This study investigated the relationship between WWI and depressive symptoms in adults.

METHODS

Participants from the National Health and Nutrition Examination Survey (2005-2018) were enrolled. Depressive symptom severity was measured with the Patient Health Questionnaire-9 (PHQ-9). Survey-weighted multivariable logistic regression, subgroup analysis, and generalized additive models were used to determine the relationship between WWI and depressive symptoms.

RESULTS

A total of 34,575 participants were included, with a mean WWI of 11.01; 2,979 participants were suspected of having depressive symptoms (PHQ-9 score ≥ 10). A significant positive association was identified between WWI and depressive symptoms (odds ratio = 1.416, 95 % confidence interval: 1.303-1.539, P < 0.0001). Subgroup analyses suggested that the association between WWI and depressive symptoms was stronger in individuals who were female, overweight, divorced, middle-aged or older (over 40 years old), and had diabetes. Furthermore, the non-linear multivariable regression revealed an inflection point for the WWI at 11.438, and the association was only significant when the WWI was higher than this point.

LIMITATIONS

This study was retrospective and only included participants from the United States; therefore, further validation is needed from studies in other countries, especially middle-to-low-income countries, using longitudinal cohorts.

CONCLUSIONS

This study identified a significant positive association between WWI and depressive symptoms.

Association between weight-adjusted-waist index and depression: a cross-sectional study

Background

Depression has become a multifaceted global health issue, with complex connections to obesity. Weight-adjusted-waist index (WWI) can effectively evaluate central obesity, but the relationship between WWI and depression has not been well studied. The study aims to investigate the potential correlation between these two health parameters.

Methods

According to the data from National Health and Nutrition Examination Survey, this cross-sectional study used multiple regression analysis, subgroup analysis, and smooth curve fitting to explore the relationship between WWI and depression. The assessment ability of WWI was evaluated and compared to other obesity indicators using the receiver operating characteristic (ROC) curve.

Results

This study analyzed 38,154 participants. Higher WWI is associated with higher depression scores (β = 0.41; 95% CI, 0.36-0.47). After adjusting for various confounding factors, the positive correlation between WWI and depression remained significant (P for trend < 0.0001). Nonlinear positive correlation was detected with a breakpoint of 11.14. ROC analysis shows that compared to other obesity indicators (ROCWWI = 0.593; ROCBMI = 0.584; and ROCWC = 0.581), the correlation between WWI and depression has better discrimination and accuracy. DII mediated 4.93%, SII mediated 5.08%, and sedentary mediated 0.35% of the total association between WWI and depression.

Conclusion

WWI levels were related to an increased likelihood of depression and showed a stronger relationship than BMI and waist circumference. Our findings indicated that WWI may serve as a simple anthropometric index to evaluate depression.

Associations between weight-adjusted-waist index and telomere length: Results from NHANES: An observational study

Previous studies have demonstrated the connection between obesity and telomere length. A recently devised metric for determining obesity, the weight-adjusted-waist index (WWI), offers a distinct advantage in predicting fat and lean mass by depicting weight-independent abdominal adiposity. This article presents the results of the inaugural study on the relationship between WWI and telomere length in adult populations. The cross-sectional investigation analyzed data from 3479 participants from the National Health and Nutrition Examination Survey (NHANES) conducted from 1999 to 2000. To inspect linear and nonlinear correlations, we adopted weighted multiple logistic regression analysis and smooth curve fit, respectively. In addition, threshold effects and subgroup analyses were accomplished. In the fully adapted model, a significant adverse association of WWI with telomere length was detected [β = -0.02, 95% CI: (-0.03, -0.00), P value = 0.01]. The adverse correlation remained consistent across all subcategories. We also discovered an inverted U-shaped curve linking WWI and telomere length, with a conspicuous inflection point of 10.07 cm/√kg. For the first time, our research demonstrated strong links between WWI and telomere length. The inflection point suggests that controlling WWI within an optimum range might be essential for aging and health.

Association between dietary folate intake and severe abdominal aorta calcification in adults: A cross-sectional analysis of the national health and nutrition examination survey

BACKGROUND

Prior studies have established a connection between folate intake and cardiovascular disease (CVD). Abdominal aortic calcification (AAC) has been introduced as a good predictor of CVD events, but no previous study has investigated the relationship between dietary folate intake and severe AAC. Therefore, the study aims to explore the association between dietary folate intake and severe AAC in the United States (US) middle-aged and elderly population.

METHODS

This study employed cross-sectional data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) to examine the relationship between dietary folate intake and severe AAC. Two 24-h dietary recall interviews were conducted to assess dietary folate intake and its sources, while a DXA scan was used to determine the AAC score. To analyze the association between dietary folate intake and severe AAC, a multivariable logistic regression model was applied, and a subgroup analysis was performed.

RESULTS

Our analysis utilized data from 2640 participants aged 40 years and above, including 288 individuals diagnosed with severe AAC. After adjusting for confounding factors, we observed an inverted L-shaped association between folate intake and severe AAC. Upon further adjustment for specific confounding factors and covariates, the multivariable-adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the second, third, and fourth quartiles of folate intake, using the first quartile as the reference, were as follows: 1.24 (0.86-1.79), 0.86 (0.58-1.27), and 0.63 (0.41-0.97), respectively. Subgroup analysis results were consistent with the logistic regression models, indicating concordant findings. Moreover, no significant interaction was observed in the subgroup analyses.

CONCLUSIONS

The study findings suggest an inverted L-shaped association between dietary folate intake and severe AAC. However, additional prospective investigations are necessary to explore the impact of dietary folate intake on severe AAC in patients.

Association between dietary selenium intake and severe abdominal aortic calcification in the United States: a cross-sectional study

Abdominal aortic calcification (AAC) is an important predictor of cardiovascular disease. The purpose of the current study was to detect the association between dietary selenium intake and severe AAC. We included 2651 participants from the National Health and Nutrition Examination Survey (NHANES, 2013-2014). Dietary selenium intake was measured using the 24-hour recall method. AAC was quantified using the Kauppila score system based on dual-energy X-ray absorptiometry, with a score of >6 indicating severe AAC. The association between dietary selenium intake and severe AAC was analyzed by using a weighted multivariate logistic regression model, smooth curve fitting, and stratified subgroup analysis. After adjusting for multiple covariates, we found that higher dietary selenium intake was negatively associated with severe AAC incidence. When selenium intake was converted into tertiles, the highest tertile of dietary selenium intake was significantly associated with the incidence of severe AAC (odds ratio = 0.66). Smooth curve fitting revealed that this relationship was nonlinear. Subgroup analysis revealed that this negative association was present in participants with chronic kidney disease, but was absent when participants had hypertension or diabetes mellitus. Higher dietary selenium intake was negatively associated with severe AAC incidence in a nonlinear pattern, except in participants with diabetes mellitus or hypertension. However, further cohort studies are required to validate these findings.

Association between the weight-adjusted waist index and the odds of type 2 diabetes mellitus in United States adults: a cross-sectional study

Objective

To examine the association between the weight-adjusted waist index (WWI) and the odds of type 2 diabetes mellitus(T2DM)among U.S. adults.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) spanning six years (2007-2018) were utilized, encompassing 31001 eligible participants. Weighted multivariate logistic regression models and smoothed fit curves were employed to assess the association between WWI and the odds of T2DM, as well as dose-response relationships in the overall population and the odds of T2DM in various subgroups.

Results

In the fully adjusted continuous model, each one-unit increase in WWI was associated with a 1.14-fold increase in the odds of T2DM within the entire study population (2.14 [1.98,2.31], P < 0.0001). In the fully adjusted categorical model, when using the lowest tertile of WWI (T1) as the reference group, the second tertile (T2) and the third tertile (T3) were associated with a 0.88-fold (1.88 [1.64,2.17], P < 0.0001) and a 2.63-fold (3.63 [3.11,4.23], P < 0.0001) increase in the odds of T2DM. These findings indicated a positive correlation between WWI values and the odds of T2DM, aligning with the results of the smoothed-fitted curves. In the analysis of subgroups, in addition to maintaining consistency with the overall population results, we found interactions between age and hypertension subgroups.

Conclusion

In conclusion, WWI was found to be positively associated with the odds of T2DM in U.S. adults.

Association between weight-adjusted-waist index and urge urinary incontinence: a cross-sectional study from NHANES 2013 to 2018

This study aimed to investigate the association between urge urinary incontinence (UUI) and weight-adjusted waist circumference index (WWI), a newly developed measure of obesity. Data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES) were included in the present cross-sectional study. Urge urinary incontinence was identified by self-reported urine leakage before reaching the toilet. Weighted multivariate logistic regression and generalized additive models were used to investigate the connection between WWI and UUI and its nonlinearity. The nonlinear relationship was explored using smoothed curve fitting. Additionally, further analyses were performed on subgroups and interaction tests were conducted. In the study, a total of 14,118 individuals were enrolled, with a UUI prevalence rate of 21.18%. Overall UUI was more prevalent with elevated WWI (OR 1.20, 95% CI 1.13-12.8, P < 0.0001), which similar results were observed in weekly (OR 1.32, 95% CI 1.18-1.48, P < 0.0001) and daily (OR 1.27, 95% CI 1.06-1.53, P = 0.0091) UUI. And this connection remained steady among all subgroups (P > 0.05 for all interactions). Smoothed curve fitting showed no nonlinear relationship between WWI and UUI. In addition, a stronger correlation was found between WWI and UUI risk than other obesity indicators such as waist circumference (WC) and body mass index (BMI). Among US adults, weight-adjusted waist circumference index values are positively associated with elevated odds of UUI and show stronger associations than WC and BMI. Further studies are required to elucidate the causal relationship between WWI and UUI.

Association between dietary calcium intake and severe abdominal aorta calcification among American adults: a cross-sectional analysis of the National Health and Nutrition Examination Survey

BACKGROUND

Evidence regarding the relationship between dietary calcium intake and severe abdominal aortic calcification (AAC) is limited. Therefore, this study aimed to investigate the association between dietary calcium intake and severe AAC in American adults based on data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

The present cross-sectional study utilized data from the NHANES 2013-2014, a population-based dataset. Dietary calcium intake was assessed using two 24-h dietary recall interviews. Quantification of the AAC scores was accomplished utilizing the Kauppila score system, whereby severe AAC was defined as having an AAC score greater than 6. We used multivariable logistic regression models, a restricted cubic spline analysis, and a two-piecewise linear regression model to show the effect of calcium intake on severe AAC.

RESULTS

Out of the 2640 individuals examined, 10.9% had severe AAC. Following the adjustment for confounding variables, an independent association was discovered between an augmented intake of dietary calcium and the incidence of severe AAC. When comparing individuals in the second quartile (Q2) of dietary calcium intake with those in the lowest quartile (Q1), a decrease in the occurrence of severe AAC was observed (odds ratio: 0.66; 95% confidence interval: 0.44-0.99). Furthermore, the relationship between dietary calcium intake and severe AAC demonstrated an L-shaped pattern, with an inflection point observed at 907.259 mg/day. Subgroup analyses revealed no significant interaction effects.

CONCLUSION

The study revealed that the relationship between dietary calcium intake and severe AAC in American adults is L-shaped, with an inflection point of 907.259 mg/day. Further research is required to confirm this association.

The relationship between obesity associated weight-adjusted waist index and the prevalence of hypertension in US adults aged ≥60 years: a brief report

Objectives

The main objective was to examine the relationship between weight-adjusted waist index (WWI) and the prevalence of hypertension among individuals aged ≥60 years who participated in the NHANES between 2011 and 2018 years.

Methods

The data for this study were obtained from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. In this population-based study, we focused on participants who were over 60 years old. Data were collected from the aforementioned survey, and the variable of interest was WWI, which was calculated as waist (cm) divided by the square root of body weight (kg). Multivariable logistic regression model was applied to calculate adjusted ORs with 95% CIs in order to explore any possible correlation between WWI and the prevalence of hypertension. Subgroup analysis were used to verify the stability of the relationship between WWI and the prevalence of hypertension. The interaction tests were also conducted in this research.

Results

Results revealed that adults aged ≥60 years who were in the highest WWI quartile had significantly higher chances of developing hypertension when compared to those in the lowest quartile, after adjusting for covariates and potential confounders (p < 0.001).

Conclusion

These findings suggest that there is a strong correlation between elevated levels of WWI and the risk of developing hypertension among older adults. As such, WWI could serve as a unique and valuable biomarker for identifying hypertension risk at an earlier stage in the older adults population.

Association between the weight-adjusted waist index and stroke: a cross-sectional study

BACKGROUND

The weight-adjusted waist index (WWI) is a new measure of obesity, and this study aimed to determine the association between the WWI and stroke.

METHODS

Using the National Health and Nutrition Examination Survey (NHANES) 2011-2020 dataset, cross-sectional data from 23,389 participants were analysed. The correlation between the WWI and stroke was investigated through multivariate logistic regression and smoothing curve fitting. Subgroup analysis and interaction tests were also carried out.

RESULTS

The research involved 23,389 participants, of whom 893 (3.82%) had a stroke. The fully adjusted model revealed a positive correlation between the WWI and stroke [1.25 (1.05, 1.48)]. Individuals who were in the highest quartile of WWI exhibited a 62% higher likelihood of experiencing a stroke than those in the lowest quartile [1.62 (1.06, 2.48)]. Subgroup analysis and interaction tests revealed that this positive correlation was similar in different population settings (all P for interaction  > 0.05).

CONCLUSION

A higher WWI was associated with a higher prevalence of stroke. The results of this study underscore the value of the WWI in stroke prevention and management.

Association between weight-adjusted-waist index and female infertility: a population-based study

Aims

Obesity is detrimental to infertility. The association between weight-adjusted-waist index (WWI, a recently developed adiposity indicator) and infertility has not previously been confirmed.

Methods

The data for this study were obtained from the National Health and Nutrition Examination Survey (NHANES) 2013-2018. Each participant's WWI was calculated as their waist circumference in centimeters by the square root of weight in kilograms. Multivariable logistic regression and generalized additive model were utilized to investigate the relationship between WWI with infertility. We used smoothed curve fitting to explore the non-linear relationship. Subgroup analysis and interaction tests were also conducted.

Results

A total of 3,526 participants with ages from18 to 45 were enrolled, 364 of whom were infertile. With the higher WWI, infertility was more prevalent (OR = 1.42, 95% CI: 1.22-1.65), and this association was still consistent in subgroups (all P for interaction> 0.05). Smoothed curve fitting showed a positive non-linear relationship between WWI and infertility. Furthermore, we discovered that WWI had a stronger connection with the risk of infertility than other markers of obesity including WC, body mass index (BMI) and a body shape index (ABSI).

Conclusions

Weight-adjusted-waist index levels were positively linked to an increased risk of infertility in American females and showed a stronger association than other markers of obesity. Our research indicated WWI could help identify women with infertility, and managing obesity as determined by WWI may help to reduce the risk of infertility.

Association of weight-adjusted-waist index with non-alcoholic fatty liver disease and liver fibrosis: a cross-sectional study based on NHANES

AIM

The purpose of this study was to explore the association of weight-adjusted-waist index (WWI) with non-alcoholic fatty liver disease (NAFLD) and liver fibrosis.

METHODS

A cross-sectional study including 6587 participants was conducted in the National Health and Nutrition Examination Survey (NHANES). Multiple linear regression was used to validate the association of WWI with NAFLD and liver fibrosis, and smoothed curve fitting and threshold effect models were used to validate non-linear relationships. Subgroup analyses were used to verify the stability of the relationship between the independent and dependent variables in different populations.

RESULTS

There was a positive association of WWI with NAFLD and liver fibrosis. In the model adjusted for all covariates, the effect values of WWI with NAFLD and liver fibrosis were (OR = 3.44, 95% CI: 3.09-3.82) and (OR = 2.40, 95% CI: 2.05-2.79), respectively. This positive correlation became more significant as WWI increased when WWI was presented in quartiles (P for trend < 0.01). Smoothed curve fitting and threshold effects analysis suggested a non-linear correlation between WWI and NAFLD (LLR < 0.01), with the positive correlation between WWI and NAFLD becoming more significant when WWI was less than 11.44 [5.93 (95% CI: 5.04-6.98)]. However, there was a linear correlation between WWI and liver fibrosis (LLR = 0.291). When subgroup analyses were performed by indicators such as age, race and gender, we found that the positive association between WWI and the dependent variables (NAFLD and liver fibrosis) was more pronounced in white male participants aged < 40 years.

CONCLUSIONS

Among adults in the United States, WWI was positively associated with the prevalence of NAFLD and liver fibrosis. Participants with a WWI less than 11.44 should be cautious about the possibility of an increased risk of NAFLD development due to a higher WWI. Meanwhile, white males younger than 40 years of age should be more cautious about the higher risk of NAFLD and liver fibrosis that might be associated with an increased WWI.

Association between weight-adjusted-waist index with hepatic steatosis and liver fibrosis: a nationally representative cross-sectional study from NHANES 2017 to 2020

Background

The negative effects of obesity on hepatic steatosis and fibrosis have received considerable attention in recent years. The weight-adjusted-waist index (WWI) reflects weight-independent centripetal obesity. Herein, we provide the first investigation of a link between WWI, hepatic steatosis, and liver fibrosis.

Methods

We used data from the National Health and Nutrition Examination Survey 2017-2020 to conduct a cross-sectional study. The linear relationship between WWI, controlled attenuation parameters, and liver stiffness measurements (LSM) was investigated using multivariate linear regression models. The nonlinear relationship was described using fitted smoothed curves and threshold effect analyses. Subgroup analyses were performed based on gender, age, body mass index, diabetes, hypertension, drinking, and smoking.

Results

This population-based study included 7,594 people, 50.74% of whom were men and 49.26% of whom were women. Multivariate linear regression analysis revealed a significant positive relationship between WWI and hepatic steatosis [CAP, β=7.60, 95% confidence interval (CI) (4.42, 10.78), P<0.0001]. This positive association was stronger when excessive alcohol intake was present compared to when it was absent (P for interaction = 0.031), and when hypertension was present compared to when it was not (P for interaction = 0.014). The linear relationship between WWI and liver fibrosis was not statistically significant on multiple regression analysis [LSM, β=0.03, 95% CI (-0.26, 0.32), P=0.84]. However, a U-shaped association was seen between WWI and LSM, with a negative correlation when WWI< 10.92 and a positive correlation when WWI > 10.92.

Conclusion

We report a strong association between WWI and hepatic steatosis, and suggest that it may potentially be used as a simple anthropometric index to predict hepatic steatosis.

Association between weight-adjusted-waist index and heart failure: Results from National Health and Nutrition Examination Survey 1999-2018

Background

Weight-adjusted waist circumference index (WWI) is a novel index positively associated with excessive fat accumulation. The current study aims to evaluate the association between WWI and the prevalent heart failure (HF), and to assess the value of WWI to improve the detection of HF in the general population.

Methods

A total of 25,509 subjects from National Health and Nutrition Examination Survey 1999-2018 were included into our study. WWI was calculated as WC (cm) divided by the square root of weight (kg). HF was identified according to the subjects' reports.

Results

The prevalence of reported HF was 2.96%. With adjustment of demographic, anthropometric, laboratory, and medical history data, one SD increment of WWI could cast an additional 19.5% risk for prevalent HF. After separating WWI into quartiles, the fourth quartile had a 1.670 times risk of prevalent HF compared to the first quartile. Furthermore, smooth curve fitting suggested that the association was linear in the entire range of WWI. Moreover, the association was robust to subgroups of age, sex, race, obesity, hypertension, and diabetes. Additionally, ROC analysis revealed a significant improvement for the detection of prevalent HF from WWI (0.890 vs. 0.894, P < 0.001); And continuous net reclassification index (0.225, P < 0.001) and integrated discrimination index (0.004, P < 0.001) also supported the improvement from WWI.

Conclusion

Our data demonstrated a significant, linear, and robust association between WWI, a simple surrogate for fat mass accumulation, and the risk for prevalent HF in a representative population. Moreover, our results also suggested the potential value of WWI to refine the detection of prevalent HF in the general population.