Associations of body mass index, waist circumference and the weight-adjusted waist index with daily living ability impairment in older Chinese people: A cross-sectional study of the Chinese Longitudinal Healthy Longevity Survey.

AIM: To investigate the associations of body mass index (BMI), waist circumference (WC) and the weight-adjusted waist index (WWI) with the impairment of activities of daily living (ADL) in older Chinese people. METHODS: A total of 13 260 participants aged 65 years and older from the 2018 Chinese Longitudinal Healthy Longevity Survey were included in this cross-sectional study. BMI, WC and the WWI were calculated from measurements of height, weight and WC. Binary logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). Non-linear correlations were investigated using restricted cubic spline curves. RESULTS: In multivariate logistic regression fully adjusted for confounding variables, our analyses revealed significant associations between WC and WWI and ADL impairment, with adjusted ORs (95% CI) of 1.01 (1.00, 1.01) and 1.08 (1.03, 1.12), respectively. Meanwhile, participants with a high WWI had a higher risk of ADL impairment compared with those with a low WWI, with an adjusted OR (95% CI) of 1.12 (1.02, 1.23). Subgroup analyses showed that only the association between WWI and ADL impairment did not differ in any of the different populations. In addition, we found that BMI, WC and WWI were non-linearly associated with ADL impairment. CONCLUSIONS: There are significant associations between WC and WWI and ADL impairment in older Chinese people. The findings show the ability of the WWI to serve as a comprehensive and effective indicator of obesity in older Chinese people and emphasize the importance of assessing WWI in screening and preventing ADL impairment in older people.

The association between weight-adjusted-waist index and psoriasis: A cross-sectional study.

INTRODUCTION: This study explored the association between psoriasis and the weight-adjusted waist index (WWI), a newly developed measure of adiposity. The research was conducted among adults in the United States. METHODS: Utilizing survey data from the National Health and Nutrition Examination Survey (NHANES) spanning the years 2009 to 2014, the present study aimed to investigate the potential correlation between psoriasis and WWI within a sample of 15,920 adult participants. Employing multivariable logistic regression and nonlinear curve fitting techniques, we analyzed this plausible association. Additionally, a subgroup analysis was conducted to ascertain the consistency across diverse populations. RESULTS: A significant positive association was discovered between psoriasis and WWI in the investigated sample of 15,920 adults. After conducting a comprehensive adjustment of the model, it was observed that each incremental unit of WWI was significantly associated with an 14% elevated likelihood of developing psoriasis (OR = 1.16, 95% CI 1.01-1.36). Moreover, individuals belonging to the highest quartile of WWI exhibited a 47% higher risk of psoriasis compared to those in the lowest quartile (OR = 1.44, 95% CI 1.01-2.06). This positive correlation remained consistent across various subgroups. The study also compared WWI with BMI and waist circumference, finding that WWI is a more stable metric of obesity. CONCLUSIONS: Our study suggested that in US adults, there is a positive association between WWI and psoriasis. It also indicated that WWI showed potential as a valuable index of psoriasis among the general population.

Association between weight-adjusted-waist index and gallstones: an analysis of the National Health and Nutrition Examination Survey.

BACKGROUND: The weight-adjusted-waist index (WWI) is a novel obesity index, and gallstones are associated with obesity. This study aimed to investigate the possible relationship between WWI and gallstones. METHODS: The datasets from the National Health and Nutrition Examination Survey (NHANES) 2017-2020 were used in a cross-sectional investigation. Multivariate linear regression models were used to examine the linear connection between WWI and gallstones incidence. Fitted smoothing curves and threshold effect analysis were used to describe the nonlinear relationship. RESULTS: The study comprised 8004 participants over the age of 20, including 833 reported with gallstones. Participants in the higher WWI tertile tended to have a higher gallstones prevalence. In the final adjusted model, a positive association between WWI and gallstones prevalence was observed (OR = 1.34, 95% CI: 1.20‒1.49). Participants in the highest WWI tertile had a significantly 71% higher risk of gallstones than those in the lowest WWI tertile (OR = 1.71, 95% CI: 1.35‒2.17). A nonlinear correlation was found between the WWI and gallstones prevalence, with an inflection point of 12.7. CONCLUSIONS: Our study found that higher WWI levels connected with increased prevalence of gallstones. However, more prospective studies are needed to validate our findings.

Association between weight-adjusted waist index and non-alcoholic fatty liver disease: a population-based study.

BACKGROUND: Obesity is the most important driver of non-alcoholic fatty liver disease (NAFLD); nevertheless, the relationship of weight-adjusted waist index (WWI), a new obesity index, with NAFLD is unclear. METHODS: This retrospective study used data from the NAGALA project from 1994 to 2016. WWI values were calculated using waist circumference (WC) and weight measurements of the participants. Three stepwise adjusted logistic regression models were developed to assess the relationship of WWI with NAFLD in the whole population and in both sexes. Additionally, we also conducted a series of exploratory analysis to test the potential impact of body mass index (BMI), age, smoking status and exercise habits on the association of WWI with NAFLD. Receiver operating characteristic (ROC) curves were used to estimate cut-off points for identifying NAFLD in the entire population and in both sexes. RESULTS: The current study included a population of 11,805 individuals who participated in health screenings, including 6,451 men and 5,354 women. After adjusting for all non-collinear variables in the multivariable logistic regression model, we found a significant positive correlation of WWI with NAFLD. For each unit increase in WWI, the risk of NAFLD increased by 72% in the entire population, by 84% in men, and by 63% in women. Furthermore, subgroup analyses revealed no significant discrepancies in the correlation of WWI with NAFLD across individuals with varying ages, exercise habits, and smoking status (all P-interaction > 0.05), except for different BMI groups (P-interaction < 0.05). Specifically, compared to the overweight/obese group, the relationship of WWI with NAFLD was significantly stronger in the non-obese group, especially in non-obese men. Finally, based on the results of ROC analysis, we determined that the WWI cut-off point used to identify NAFLD was 9.7675 in men and 9.9987 in women. CONCLUSIONS: This study is the first to establish a positive correlation between WWI and NAFLD. Moreover, assessing the influence of WWI on NAFLD in individuals without obesity may yield more valuable insights compared to those who are overweight or obese.

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 (ß: 0.48, 95% CI: 0.43, 0.53) between the WWI and HOMA-IR. The HOMA-IR was lower in physically active (ß: -0.16, 95% CI: -0.26, -0.05) participants versus inactive participants. Participants who had higher WWI and were not physically active (ß: 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.

Weight-adjusted waist index as a practical predictor for diabetes, cardiovascular disease, and non-accidental mortality risk.

BACKGROUND AND AIM: Identifying a more suitable marker among various measures of adiposity, demonstrating strong associations and predictive ability for clinical use, remains a topic of debate. Weight-adjusted waist index (WWI) has been proposed as a novel index of adiposity, yet its exploration is limited, especially in Chinese populations. This study seeks to examine the associations between body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHTR), weight-adjusted waist index (WWI), waist circumference divided by body mass to the power of 0.333 (WC/M0.333), visceral adiposity index (VAI), lipid accumulation product (LAP), and the incidence of diabetes, cardiovascular disease, and non-accidental mortality in Chinese populations. Furthermore, our goal is to compare the respective predictive values of these measures for these health outcomes. METHODS AND RESULTS: This prospective cohort study included 21,750 subjects with a 9-year follow-up period. Cox proportional hazard models were used to investigate the relationship between eight anthropometric indexes and the incidence of diabetes, cardiovascular disease, and non-accidental mortality. The predictive value of these eight indexes was compared using the area under the curve metric. Significant positive associations were found between WWI and the risk of diabetes. Using the first quartile (Q1) of WWI as the reference group, hazard ratios with 95% confidence intervals for the risk of diabetes were 1.58 (0.98-2.55) for Q2, 2.18 (1.34-3.35) for Q3, and 2.27 (1.41-3.67) for Q4. Significant associations were observed with the highest quartile of WWI for the risk of cardiovascular disease [Q2: HR 1.45 (95% CI 1.06-1.98); Q3: 1.33 (0.97-1.83); Q4: 1.55 (1.13-2.14)] and risk of non-accidental mortality [Q2: 0.94 (0.80-1.11); Q3: 1.24 (1.04-1.48); Q4: 1.44 (1.16-1.79)]. Receiver operating characteristic analysis revealed that WWI exhibited superior discrimination and accuracy in predicting cardiovascular disease and non-accidental mortality compared to other adiposity indexes (BMI, WC, WHR, WHTR, WC/M0.333, VAI, and LAP). CONCLUSION: WWI exhibited the most robust and consistent association with the incidence of cardiovascular disease and non-accidental mortality. Given its simplicity and widespread use, WWI emerges as a novel and practical predictor of diabetes, cardiovascular disease, and non-accidental mortality among the eight adiposity indexes investigated in this study.

Relationship between weight-adjusted-waist index and blood pressure as well as incident hypertension among middle-aged and elderly Chinese: A longitudinal study.

BACKGROUND AND AIM: The Weight-Adjusted Waist Index (WWI) is a novel obesity metric linked to metabolic disorders. Its relationship with blood pressure and hypertension prevalence in middle-aged and elderly Chinese is unclear. This study examined the association between WWI, blood pressure, and hypertension incidence. METHODS AND RESULTS: This cross-sectional study included 9298 participants from the China Health and Retirement Longitudinal Study, with 4120 non-hypertensive individuals enrolled in the cohort study. In the cross-sectional analysis, WWI was positively associated with systolic blood pressure (SBP) (Beta 0.88, 95% CI: 0.57-1.21, p < 0.001), showing stronger correlations than waist circumference (WC) (Beta 0.20, 95% CI: 0.16-0.23, p < 0.001) and body mass index (BMI) (Beta 0.63, 95% CI: 0.52-0.74, p < 0.001). WWI also showed a positive association with diastolic blood pressure (DBP) (Beta 0.51, 95% CI: 0.32-0.69, p < 0.001), stronger than those with WC (Beta 0.13, 95% CI: 0.11-0.15, p < 0.001) and BMI (Beta 0.43, 95% CI: 0.37-0.50, p < 0.001). In the longitudinal cohort study, there were 1325 (32%) incident cases of hypertension by the end of follow-up. WWI was positively associated with incident hypertension (OR 1.11, 95% CI: 1.04-1.18, p = 0.001), with a stronger predictive value than WC (OR 1.02, 95% CI: 1.01-1.03, p < 0.001) and BMI (OR 1.04, 95% CI: 1.02-1.06, p < 0.001). CONCLUSION: Elevated WWI may serve as an independent risk factor for incident hypertension in the middle-aged and elderly Chinese population.

Association between weight-adjusted waist index and overactive bladder syndrome among adult women in the United States: a cross-sectional study.

PURPOSE: The weight-adjusted waist index (WWI) is a recently developed index for measuring obesity. The aim of this study was to investigate the association between WWI levels and overactive bladder (OAB) in a nationally representative population. METHODS: This cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES) database between 2007 and 2016. OAB was defined as the Overactive Bladder Syndrome Symptom Score (OABSS, score ≥ 3). The WWI index was calculated as the square root of waist circumference (WC, cm) divided by body weight (kg). We used weighted logistic regression models to assess the relationship between the WWI index and OAB in adult women. The reliability of the findings was assessed using restricted cubic spline, subgroup analysis. RESULTS: A total of 10,563 individuals were included in the study, and the prevalence of OAB was 18.6%. Higher WWI was associated with an increased risk of overactive bladder syndrome. In model 1 with unadjusted variables (OR = 1.148; 95% CI = 1.148-1.149, p < 0.001), model 2 (OR = 1.253; 95% CI = 1.253-1.254, p < 0.001) and model 3 with fully adjusted variables (OR = 1.215; 95% CI = 1.214-1.215, p < 0.001) in which the association was significant. The results of the subgroup analyses showed that age stratification and stroke status could modify this association between WWI and OAB. Restricted cubic spline showed a nonlinear relationship between WWI and OAB (p for nonlinear < 0.05). CONCLUSION: Weight-adjusted waist circumference index (WWI) values are positively associated with the risk of developing OAB in adult women in the United States, but further studies are needed to elucidate the causal relationship between WWI and OAB.

Association between weight-adjusted waist index and myopia in adolescents and young adults: results from NHANES 1999-2008.

BACKGROUND: Previous studies have indicated a possible link between obesity and myopia, although the results have varied. The objective of this study was to investigate the correlation between a new measure of obesity, the weight-adjusted waist index (WWI), and myopia. METHOD: This cross-sectional study included individuals between the ages of 12 and 25 who participated in a noncycloplegic vision examination as part of the National Health and Nutrition Examination Survey (NHANES) conducted from 1999 to 2008. WWI was calculated as waist circumference divided by the square root of body weight. Myopia was characterized by a spherical equivalent (SE) of ≤ - 0.5 diopters (D) and further categorized into mild (-3.00D < SE≤-0.50 D), moderate (-6.00D < SE ≤-3.00 D), or high (SE≤-6.00 D). We utilized a weighted multivariable logistic regression and a generalized additive model to evaluate the correlation between WWI and myopia. Threshold effects were analyzed, and we performed subgroup analysis and interaction tests. RESULTS: A grand total of 11,180 individuals were registered for the study. Decreased myopia severity was observed with higher WWI, as evidenced by elevated SE (ß = 0.098, 95% CI: 0.028-0.167). Individuals in the top tertile of WWI experienced a 19.8% decrease in risk compared to those in the lowest group (OR = 0.802, 95% CI: 0.800-0.804; P for trend < 0.001). Similar associations were observed for high myopia. Gender-specific nonlinear associations were found, with different breakpoints for males (10.774) and females (10.025). In males, a significant positive association was found on the right side of the breakpoint (OR = 1.398, 95% CI: 1.038-1.884), while no significant association was found on the left side. Conversely, among females, a negative association was observed on the left side of the breakpoint (OR = 0.679, 95% CI: 0.512-0.899), whereas no notable correlation was detected on the right side. CONCLUSION: Increased WWI level was linked to a lower risk of myopia and high myopia in the overall sample, with gender-specific variations.

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.

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 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 (ß=-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 (ß=-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.

The association between Weight-adjusted-Waist Index (WWI) and cognitive function in older adults: a cross-sectional NHANES 2011-2014 study.

BACKGROUND: The impact of obesity on cognitive function has engendered considerable interest. Weight-adjusted waist index (WWI) has emerged as a novel and innovative marker of obesity that reflects weight-independent abdominal obesity. However, the association between WWI and cognitive function remains unclear. To address this gap, the present study aims to explore the relationship between weight-adjusted waist index (WWI) and cognitive performance in older adults. METHODS: We conducted a cross-sectional investigation using datasets from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. The study included 3,472 participants (48.59% male, 51.41% female) of various races (Mexican American, Other Hispanic, Non-Hispanic White, Non-Hispanic Black, and Other), with a mean age of 69.95 years (SD = 6.94). Multivariate regression and smoothing curve fitting were used to investigate the linear and nonlinear relationship between WWI and cognitive performance in the following domains: learning and memory, verbal fluency, and processing speed, as measured by Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD-WL), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST), respectively. Subgroup analysis and interaction tests were conducted to examine the stability of this relationship across groups. Machine learning models based on random forests were used to analyze the predictive performance of WWI for cognitive function. RESULTS: A total of 3,472 participants were included in the analysis. The results revealed significant negative associations between WWI and low scores on the CERAD-WL [-0.96 (-1.30, -0.62)], AFT [-0.77 (-1.05, -0.49)], and DSST [-3.67 (-4.55, -2.79)]. This relationship remained stable after converting WWI to a categorical variable. In addition, this significant negative association was more pronounced in men than women and diminished with advancing age. Non-linear threshold effects were observed, with correlations intensifying between WWI and CERAD-WL when WWI surpassed 12.25, AFT when WWI surpassed 11.54, and DSST when WWI surpassed 11.66. CONCLUSIONS: A higher WWI, indicating increased abdominal obesity, was associated with deficits in learning, memory, verbal fluency, and processing speed among older adults. These findings suggest that abdominal obesity may play a crucial role in cognitive decline in this population. The stronger relationship observed between WWI and cognition in men highlights the need for gender-specific considerations in interventions targeting abdominal obesity. The results demonstrate the importance of interventions targeting abdominal obesity to preserve cognitive performance in older adults.

Association between weight-adjusted waist index and risk of diabetes mellitus type 2 in United States adults and the predictive value of obesity indicators.

BACKGROUND: The weight-adjusted waist index (WWI) is a quantitative anthropometric index that can be applied to evaluate obesity. This study examined the relationship between adult United States (US) residents' risk of diabetes mellitus type 2 (T2DM) and WWI. METHODS: The NHANES (National Health and Nutrition Examination Survey) 2001-2018 provided the data for this investigation. This study used multifactorial logistic regression analysis, smoothed curve fitting, subgroup analysis, and interaction tests to assess the association between WWI and T2DM. Additionally, threshold effects were calculated using a two-stage linear regression model. The receiver operating characteristic(ROC) curves evaluated the diagnostic ability of the WWI and commonly used obesity indicators. RESULTS: 20,477 participants were enrolled in the analysis, and patients with greater levels of WWI had a higher prevalence of T2DM. WWI and T2DM have a non-linear relationship, with a positive association found on the left side of the breakpoint (WWI = 12.35) (OR = 1.82, 95%CI:1.64-2.02), whereas, on the right side, no such relationship was found (OR = 0.9, 95%CI:0.61-1.34). For every unit rise in WWI, the probability of having T2DM increased by 67% after controlling for all other variables (OR:1.67,95%CI:1.53-1.83). Based on subgroup analyses, individuals under 40 had a higher correlation between WWI and T2DM (P < 0.001).ROC analyses showed that WWI had the best discrimination and accuracy in predicting T2DM compared to other obesity indicators (WC, BMI, and Weight). CONCLUSION: Higher WWI values had a higher prevalence of T2DM in US individuals, especially in adults under 40. WWI has the strongest ability to predict T2DM. Therefore, the importance of WWI in the early identification of T2DM in US adults should be emphasized.

Association of changes in waist circumference, waist-to-height ratio and weight-adjusted-waist index with multimorbidity among older Chinese adults: results from the Chinese longitudinal healthy longevity survey (CLHLS).

BACKGROUND: The association of changes in waist circumference (WC), waist-to-height ratio (WHtR) and weight-adjusted-waist index (WWI) with subsequent risk of multimorbidity remains unclear among older Chinese adults. Therefore, we aimed to assess this association by utilizing data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). METHODS: Our study was based on the 2011/2012 wave of the CLHLS whose follow-up surveys were conducted in 2014 and 2017/2018. A total of 2900 participants aged 65 and above at baseline were enrolled. WC, WHtR, and WWI were calculated from measured height, weight, and waist circumference. Multimorbidity refers to the coexistence of two or more of 18 chronic diseases. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95%CIs) to evaluate the effect of three-year changes in WC, WHtR, and WWI on the risk of multimorbidity. RESULTS: During a mean follow-up time of 4.2 (2.0) years, 906 multimorbidity cases were identified. Compared to participants in the persistently low WC group, those in the WC gain group and the persistently high WC group had a higher multimorbidity risk with adjusted HRs (95%CI) of 1.23 (1.01-1.50) and 1.34(1.14-1.58), respectively. Participants in the WHtR gain group and the persistently high WHtR group also had higher risks of multimorbidity with HRs (95%CI) of 1.35 (1.08-1.67) and 1.27 (1.05-1.53), respectively, relative to the persistently low WHtR group. Compared to the persistently low WWI group, those in the WWI loss group had a lower risk of multimorbidity with HRs (95%CI) of 0.80 (0.66-0.98). For every standard deviation increase in WC, WHtR, and WWI over three years, the risk of multimorbidity was higher by 12% (95%CI: 1.05-1.19), 13% (95%CI: 1.06-1.20), and 12% (95%CI: 1.05-1.20), respectively. CONCLUSIONS: Associations of changes in WC, WHtR and WWI with multimorbidity are significant among older Chinese adults. The findings highlight the importance of evaluating changes in WC, WHtR, and WWI in screening and prevention of multimorbidity in older adults.

Relationship between the weight-adjusted-waist index and kidney stone: a population-based study.

BACKGROUND: At present, a growing number of studies have shown a positive association between obesity and kidney stone, while traditional anthropometric measures, such as body mass index (BMI) and Waist circumference (WC), have limited ability to assess the risk of kidney stone. Therefore, this study aimed to investigate the association between the weight-adjusted-waist index (WWI) and the risk of kidney stone. METHOD: Data from the National Health and Nutrition Examination Survey (NHANES) between 2009 and 2016 were used. A total of 17,292 participants from NHANES were included in the study. Multivariate logistic regression and restricted cubic splines (RCS) were used to investigate the relationship between WWI and kidney stone. Interaction analysis was performed for subgroups to verify the results. Meanwhile, the receiver operating characteristic curve (ROC) was used to analyze the efficacy of different anthropometric indices in predicting the risk of kidney stone. RESULTS: After adjusting for potential confounding factors, we found a positive and independent association between kidney stone and WWI. After adjusting for all covariates, a one-unit increase in WWI was associated with a 36% increase in the risk of kidney stones. Dose-response curve analysis showed that WWI was non-linear correlated with the prevalence of kidney stone. In ROC analysis, WWI showed better discrimination for kidney stone (area under the curve: 0.612; 95% CI: 0.599-0.626; optimal cutoff value: 11.063) compared with other indices. CONCLUSION: In this study, increased WWI was strongly associated with the risk of kidney stone.

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.

Positive association between weight-adjusted-waist index and dementia in the Chinese population with hypertension: a cross-sectional study.

PURPOSE: The links between obesity and dementia remain equivocal. Therefore, this study aimed to explore the association between weight-adjusted waist index (WWI), a new anthropometric indicator reflecting obesity, and dementia in the Chinese population with hypertension. METHODS: A total of 10,289 participants with hypertension were enrolled in this cross-sectional study, a subset of the China H-type hypertension registry study. WWI was calculated as waist circumference (WC) divided by the square root of bodyweight. Mini-mental state examination (MMSE) scale was performed to evaluate the cognitive function. According to educational background, different MMSE cut-off values were applied to define dementia: < 24 for participants with ≥ 7 years of education, < 20 for those with 1-6 years of education, and < 17 for illiterate participants. Multivariable linear regression and multivariable binary logistic regression analyses were conducted to assess the associations between WWI and MMSE and dementia, respectively. RESULTS: Overall, the mean age was 63.7 ± 9.7 years, and 49.0% were males. Multivariate linear regression analyses showed that WWI was negatively associated with MMSE (ß, -1.09; 95% confidence interval [CI]: -1.24, -0.94). Consistently, multivariable binary logistic regression analyses found a positive association between WWI and the risk of dementia (odds ratio [OR], 1.45; 95% CI: 1.35, 1.56). Compared with individuals in quartile 1 of WWI, the adjusted ß and OR values of WWI for MMSE and dementia were -2.28 (95% CI: -2.62, -1.94) and 2.12 (95% CI: 1.81, 2.48), respectively. Results of smoothing curve fitting confirmed the linear association between WWI and MMSE and dementia. Subgroup analysis showed a stronger association between WWI and dementia in participants with hypertension with midday napping. CONCLUSION: WWI was independently and positively associated with dementia among the population with hypertension, especially in those with midday napping. The data suggests that WWI may serve as a simple and effective tool for the assessment of the risk of dementia in clinical practice.

Weight-adjusted waist index is not superior to conventional anthropometric indices for predicting type 2 diabetes: a secondary analysis of a retrospective cohort study.

BACKGROUND: Weight-adjusted waist index (WWI) is a new anthropometric indicator to assess adiposity. Current knowledge regarding its association with type 2 diabetes mellitus (T2DM) is limited. This present study aims to evaluate the association of WWI with the risk of T2DM in the Japanese population, and to compare its predictive ability with body mass index (BMI) and waist circumference (WC). METHODS: This was a secondary analysis of a retrospective cohort study involving 15,464 participants. Participants were divided into quartiles based on baseline WWI levels. Cox regression model, Kaplan-Meier curve, and smooth curve fitting were used to explore the relationship between WWI and T2DM. The discriminative ability of obesity indices in predicting T2DM was compared by the receiver operating characteristic (ROC) curve. RESULTS: After a mean follow-up of 6.05 years, 373 participants were diagnosed with T2DM. In fully adjusted models, the risk of incident T2DM was 1.96 times higher for each 1-unit increment in WWI levels (95% CI: 1.61-2.39, P < 0.001). Smooth curve fitting analysis showed a linear positive association between baseline WWI and new-onset T2DM. Subgroup analysis showed consistent results which subjects in the 4th WWI quartile had the highest risk of developing T2DM in different age, gender, and BMI groups. WWI did not exhibit better predictive ability compared with BMI and WC in the results of ROC curve. CONCLUSION: WWI, a new metabolic index, can be used to predict new-onset T2DM in the Japanese population. However, its predictive capability was not superior to conventional anthropometric indices.

Relationship Between Weight-Adjusted Waist Index and Osteoporosis in the Senile in the United States from the National Health and Nutrition Examination Survey, 2017-2020.

BACKGROUND: Some studies suggested obesity may be beneficial in preventing bone loss through the negative relationship between body mass index (BMI) and osteoporosis in senile. However, using BMI to measure obesity is unconvincing due to confounding factors such as muscle mass were not taken into account, and few articles have yet taken a better way to evaluate the relationship between obesity and osteoporosis. METHODOLOGY: Using a cross-sectional sample of 1,979 participants aged ≥65 years from the National Health and Nutrition Examination Survey (NHANES) 2017 to 2020, we evaluated the relation of weight-adjusted waist index (WWI) with osteoporosis. WWI was calculated as waist (cm) divided by the square root of body weight (kg). Diagnosis of osteoporosis was described as follows: according to the updated reference for calculating bone mineral density T-Scores, we marked the BMD value as X, using the formula T femoral neck= (X g/cm2-0.888 g/cm2)/0.121 g/cm2, T lumbar spine= (X g/cm2- 1.065 g/cm2)/0.122 g/cm2, and defined those with a final T femoral neck <-0.25. T lumbar spine<-0.25 or patients with previously diagnosed OP in other hospitals as osteoporosis. RESULTS: All the 1,979 participants were between 65 and 80 years, there were 379 (21.1%) with osteoporosis, 608 (30.7%) with WWI exceeding 12 (cm/√kg) (range 8.85-14.14), and 955 (48.3%) women. Furthermore, the relationship between WWI and osteoporosis was nonlinear with a threshold effect point. Odds of OP significantly increased with the increase of WWI (OR 2.33, 95% CI 11.48-3.38, P = 0.0001) at the right side of the threshold point (WWI≥12) according to the threshold effect study. CONCLUSIONS: Found a significant positive relationship between WWI and osteoporosis. Body fat management in the senile may be good to prevent osteoporosis if confirmed by other prospective studies analyzing the longitudinal risk of osteoporosis with obesity.