Sensitivity and specificity of the body mass index for the diagnosis of overweight/obesity in elderly

Obesity Disparities Among Adult Single-Race and Multiracial Asian and Pacific Islander Populations

Importance

Despite increasing numbers of multiracial individuals, they are often excluded in studies or aggregated within larger race and ethnicity groups due to small sample sizes.

Objective

To examine disparities in the prevalence of obesity among single-race and multiracial Asian and Pacific Islander individuals compared with non-Hispanic White (hereafter, White) individuals.

Design, Setting, and Participants

This cross-sectional study used electronic health record (EHR) data linked to social determinants of health and health behavior data for adult (age ≥18 years) members of 2 large health care systems in California and Hawai'i who had at least 1 ambulatory visit to a primary care practitioner between January 1, 2006, and December 31, 2018. Data were analyzed from October 31, 2022, to July 31, 2023.

Exposure

Self-identified race and ethnicity provided in the EHR as a single-race category (Asian Indian, Chinese, Filipino, Japanese, Native Hawaiian only, Other Pacific Islander, or White) or a multiracial category (Asian and Pacific Islander; Asian, Pacific Islander, and White; Asian and White; or Pacific Islander and White).

Main Outcomes and Measures

The main outcome was obesity (body mass index [BMI] ≥30.0), based on last measured height and weight from the EHR. Logistic regression was used to examine the association between race and ethnicity and odds of obesity.

Results

A total of 5229 individuals (3055 [58.4%] male; mean [SD] age, 70.73 [11.51] years) were examined, of whom 444 (8.5%) were Asian Indian; 1091 (20.9%), Chinese; 483 (9.2%), Filipino; 666 (12.7%), Japanese; 91 (1.7%), Native Hawaiian; 95 (1.8%), Other Pacific Islander; and 888 (17.0%), White. The percentages of individuals who identified as multiracial were as follows: 417 (8.0%) were Asian and Pacific Islander; 392 (7.5%), Asian, Pacific Islander, and White; 248 (4.7%), Asian and White; and 414 (7.9%), Pacific Islander and White. A total of 1333 participants (25.5%) were classified as having obesity based on standard BMI criteria. Obesity was highest among people who identified as Asian, Pacific Islander, and White (204 of 392 [52.0%]) followed by those who identified as Other Pacific Islander (47 of 95 [49.5%]), Native Hawaiian (44 of 91 [48.4%]), and Pacific Islander and White (186 of 414 [44.9%]). After accounting for demographic, socioeconomic, and health behavior factors, people who identified as Asian, Pacific Islander, and White (odds ratio [OR], 1.80; 95% CI, 1.37-2.38) or Pacific Islander and White (OR, 1.55; 95% CI, 1.18-2.04) had increased odds of obesity compared with White individuals. All single-race Asian groups had lower odds of obesity compared with White individuals: Asian Indian (OR, 0.29; 95% CI, 0.20-0.40), Chinese (OR, 0.22; 95% CI, 0.17-0.29), Filipino (OR, 0.46; 95% CI, 0.35-0.62), and Japanese (OR, 0.38, 95% CI, 0.29-0.50).

Conclusions and Relevance

In this study, multiracial Asian and Pacific Islander individuals had an increased prevalence of obesity compared with many of their single-race counterparts. As the number of multiracial individuals increases, it will be important for clinical and public health systems to track disparities in these populations.

Assessment of the performance of the body mass index in diagnosing obesity in community-dwelling older adults in Latin American and Caribbean countries

BACKGROUND

The body mass index (BMI) ≥30 kg/m2 is the universally accepted cut-off point for defining obesity; however, its accuracy in classifying obesity in older adults is poorly understood.

OBJECTIVES

To assess the performance of the BMI cut-off point ≥30 kg/m2 in classifying obesity in older adults, using the fat mass index (FMI) and fat mass percentage (FM%) as reference criteria; and to establish region- and sex-specific BMI-based cut-off points to classify obesity in older adults.

METHODS

The present study is a secondary analysis derived from a cross-sectional project that included a sample of 1463 older adults from ten Latin American and Caribbean countries. Volunteers underwent total body water measurements using the deuterium dilution technique to determine FMI and FM%. Accuracy of the BMI and derived cutoff points was assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

The BMI cut-off point ≥30 kg/m2 had low sensitivity for classifying obesity in these older adults compared to the FMI and FM%. The AUC values for the optimal BMI-derived cut-off points showed an acceptable-to-outstanding discriminatory capacity in diagnosing obesity defined by the FMI. There was also a better balance between sensitivity and specificity than with the values obtained by a BMI ≥30 kg/m2 in older subjects in both regions.

CONCLUSION

The BMI cut-off point ≥30 kg/m2 had poor sensitivity for accurately diagnosing obesity in older adults from two regions. The region- and sex-specific BMI-derived cut-off points for defining obesity using the FMI are more accurate in classifying obesity in older men and women subjects from both regions.

Accuracy of body mass index compared to whole-body dual energy X-ray absorptiometry in diagnosing obesity in adults in the Eastern Province of Saudi Arabia: A cross-sectional study

BACKGROUND

Obesity is a major health concern that requires accurate diagnosis and management. Body mass index (BMI) commonly used to diagnose obesity, has limitations in accurately assessing body fat. Body fat percentage (BF%) from whole-body dual energy X-ray absorptiometry (DEXA) scans is gaining popularity as a more accurate method in diagnosing obesity.

MATERIALS AND METHODS

This cross-sectional study included 319 adult patients who underwent whole-body DEXA scans in the Eastern Province of Saudi Arabia from May 2016 to December 2021 were recruited from three medical centers, where data for whole-body DEXA were available. Body fat percent was obtained from the whole-body DEXA scan reports and were compared to BMI to evaluate prevalence of obesity. Data was extracted by reviewing patients' records using a structured data collection tool. BMI was defined using WHO criteria, and diagnostic performance was assessed by estimating specificity, sensitivity, likelihood ratios, and predictive values, and by constructing receiver operating characteristic (ROC) curves for BMI to detect obesity by age group.

RESULTS

The gender-specific BF% cutoff points revealed a higher prevalence of obesity than BMI cutoff points. BMI misclassified 40.6% of participants, and optimal cutoff points yielding highest area under the curve were 24 kg/m2 and 24.3 kg/m2 for males and females, respectively.

CONCLUSION

The study underscores the importance of using accurate and comprehensive diagnostic tools such as whole-body DEXA scans to assess obesity.

Relationship between Outerbridge Scale and Chondropathy Femorotibial Joint in Relation to Gender and Age-The Use of 1.5T and 3.0T MRI Scanners

Background and Objective: Magnetic resonance imaging (MRI) enables the effective evaluation of chondromalacia of the knee joint. Cartilage disease is affected by many factors, including gender, age, and body mass index (BMI). The aim of this study was to check the relationship between the severity of chondromalacia of the femoro-tibial joint and age, gender, and BMI assessed with 1.5T and 3.0T MRI scanners. Materials and Methods: The cross-observational study included 324 patients—159 (49%) females and 165 (51%) males aged 8−87 (45.1 ± 20.9). The BMI of study group was between 14.3 and 47.3 (27.7 ± 5.02). 1.5T and 3.0T MRI scanners were used in the study. The articular cartilage of the knee joint was assessed using the Outerbridge scale. Results: The age of the patients showed a significant correlation with Outerbrige for each compartment of the femorotibial joint (Spearman’s rank correlation rho: 0.69−0.74, p < 0.0001). A higher correlation between BMI and Outerbridge was noted in the femur medial (rho = 0.45, p < 0.001) and the tibia medial (rho = 0.43, p < 0.001) than in the femur lateral (rho = 0.29, p < 0.001) and the tibia lateral compartment (rho = 0.34, p < 0.001). Conclusions: The severity of chondromalacia significantly depends on age and BMI level, regardless of gender.

Oral health and Obesity in Brazilian elders: A longitudinal study

OBJECTIVES

Obesity is an important risk factor for chronic diseases and can also result in greater mortality. The aim of this longitudinal study was to investigate whether poor oral health acts as a risk factor for obesity as indicated by body mass index (BMI) and waist circumference (WC).

METHODS

We included in this analysis all participants who volunteered in a cohort study entitled 'Carlos Barbosa Cohort Study-CBCS' in the city of Carlos Barbosa, Southern Brazil. The interview questionnaire comprised socio-demographic information, behavioural questions and medical history. Oral examinations and anthropometric assessments were carried out. The outcome was obesity measured by both BMI (≥30 kg/m² ) and WC (>0.80 for women and >0.94 for men). Variables were collected longitudinally. Those associated with the outcome and epidemiologically relevant to the conceptual framework participated in the analysis and were adjusted for socio-demographic, behavioural, general and oral health conditions.

RESULTS

Six hundred and thirty-three independently living elders participated. The baseline mean age was 67.5 ± 6.1 years. Individuals who never visited a dentist (OR = 3.02, 95% CI: 1.25-7.26) as well as participants who needed a dental prosthesis in the lower arch (OR = 4.38, 95% CI: 1.34-14.32) were more likely to be obese, through BMI and WC measures, respectively. Edentulous participants with complete dentures in both arches (OR = 0.23, 95% CI: 0.06-0.84) and those who perceived their oral health as unsatisfactory (OR = 0.41, 95% CI: 0.19-0.88) had a lower likelihood of being obese, according to BMI and WC measures.

CONCLUSIONS

Older persons with poor oral health may be at risk for general and central obesity, a relationship that may have important clinical implications.

The performance of anthropometric tools to determine obesity: a systematic review and meta-analysis

The aim of this systematic review was to assess the performance of anthropometric tools to determine obesity in the general population (CRD42018086888). Our review included 32 studies. To detect obesity with body mass index (BMI), the meta-analyses rendered a sensitivity of 51.4% (95% CI 38.5-64.2%) and a specificity of 95.4% (95% CI 90.7-97.8%) in women, and 49.6% (95% CI 34.8-64.5%) and 97.3% (95% CI 92.1-99.1%), respectively, in men. For waist circumference (WC), the summary estimates for the sensitivity were 62.4% (95% CI 49.2-73.9%) and 88.1% for the specificity (95% CI 77.0-94.2%) in men, and 57.0% (95% CI 32.2-79.0%) and 94.8% (95% CI 85.8-98.2%), respectively, in women. The data were insufficient to pool the results for waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) but were similar to BMI and WC. In conclusion, BMI and WC have serious limitations for use as obesity screening tools in clinical practice despite their widespread use. No evidence supports that WHR and WHtR are more suitable than BMI or WC to assess body fat. However, due to the lack of more accurate and feasible alternatives, BMI and WC might still have a role as initial tools for assessing individuals for excess adiposity until new evidence emerges.

Weight perceptions in older adults: findings from the English Longitudinal Study of Ageing

OBJECTIVES

To explore weight perceptions in a large, nationally representative sample of older adults, and the extent to which they differ according to age and perceived health status.

SETTING

England.

PARTICIPANTS

5240 men and women (≥50 years old) participating in the English Longitudinal Study of Ageing (2016/2017).

MAIN OUTCOME MEASURES

Weight perception was self-reported as too heavy, too light or about right.

RESULTS

The majority of older adults endorsed a weight perception that matched their (objectively measured) body mass index (BMI) classification. However, 1 in 10 (9.9%) older adults classified by BMI as normal weight (18.5-24.9 kg/m2) felt too light, with women at the upper end of the older age spectrum (OR=1.04, 95% CI 1.01 to 1.09), and men (OR=3.70, 95% CI 1.88 to 7.28) and women (OR=2.61, 95% CI 1.27 to 5.35) in poorer health more likely to do so. Almost half (44.8%) of older adults classified as overweight (25-29.9 kg/m2) and 1 in 10 (10.3%) classified as obese (≥30 kg/m2) felt about the right weight, with this observed more frequently among men and women at the upper end of the older age spectrum (OR range 1.04-1.06).

CONCLUSION

Older adults' perceptions of their own weight generally correspond with traditional BMI cut-offs for normal weight, overweight and obesity. However, a substantial minority 'underestimate' their weight status, with those at the upper end of the age spectrum and those in poorer health more likely to do so.

Relationship between obesity indices and hypertension among middle-aged and elderly populations in Taiwan: a community-based, cross-sectional study

OBJECTIVE

Obesity and hypertension (HTN) have become increasingly prevalent in Taiwan. People with obesity are more likely to have HTN. In this study, we evaluated several anthropometric measurements for the prediction of HTN in middle-aged and elderly populations in Taiwan.

DESIGN

Cross-sectional observational study.

SETTING

Community-based investigation in Guishan Township of northern Taiwan.

PARTICIPANTS

A total of 396 people were recruited from a northern Taiwan community for a cross-sectional study. Anthropometrics and blood pressure were measured at the annual health exam. The obesity indices included body mass index (BMI), body fat (BF) percentage and waist circumference (WC).

OUTCOME MEASURES

Statistical analyses, including Pearson's correlation, multiple logistic regression and the area under ROC curves (AUCs) between HTN and anthropometric measurements, were used in this study.

RESULTS

Of the 396 people recruited, 200 had HTN. The age-adjusted Pearson's coefficients of BMI, BF percentage and WC were 0.23 (p<0.001), 0.14 (p=0.01) and 0.26 (p<0.001), respectively. Multiple logistic regression of the HTN-related obesity indices showed that the ORs of BMI, BF percentage and WC were 1.15 (95% CI 1.08 to 1.23, p<0.001), 1.07 (95% CI 1.03 to 1.11, p<0.001) and 1.06 (95% CI 1.03 to 1.08, p<0.001), respectively. The AUCs of BMI, BF percentage and WC were 0.626 (95% CI 0.572 to 0.681, p<0.001), 0.556 (95% CI 0.500 to 0.613, p=0.052) and 0.640 (95% CI 0.586 to 0.694, p<0.001), respectively.

CONCLUSIONS

WC is a more reliable predictor of HTN than BMI or BF percentage. The effect of abdominal fat distribution on blood pressure is greater than that of total BF amount.

Accuracy of BMI and waist circumference cut-off points to predict obesity in older adults

The main objectives were to analyse the validity and accuracy of Body Mass Index (BMI) and Waist Circumference (WC) to evaluate obesity by excess of body fat in older adults and to identify more adequate cut-off points for this age group. The recommended cut-off points for BMI (25, 27 or 30 kg/m2) and WC (≥ 102 cm for men and ≥ 88 cm for women or ≥ 90cm for men and ≥ 80 cm for women) were compared to the total body densitometry. BF was defined by a value higher than the 90th percentile. Out of the 132 participants, 61% were women and aged between 60 and 91 years. The recommended cut-off points of BMI ≥ 25kg/m2 and BMI ≥ 27 kg/m2 showed similar performances. BMI ≥ 30 kg/m2 showed high specificity but low sensitivity to identify BF in men and better performance in women. Conventional WC cut-off points showed low sensitivity and specificity. Based on our analyses, new cut-off points for BMI (25 kg/m2 for men and 26.6 kg/m2 for women) and WC (98.8 cm for men and 77.8cm for women) were proposed. The new cut-off points showed sensitivity and specificity values > 74% and accuracy > 76%. The areas under the curve (ROC) were > 0.86. The new BMI and WC cut-off points proposed in the present study for the diagnosis of obesity in older adults showed the best levels of sensitivity and specificity for this age group.

Limitations of body mass index to assess body composition due to sarcopenic obesity during leukemia therapy

Obesity as defined by body mass index percentile (BMI%) is strongly associated with relapse and poorer survival in childhood ALL. Whether BMI% accurately reflects body fat percentage (BF%) in this population is unknown. We conducted a prospective study assessing body composition during frontline ALL therapy. Dual-energy X-ray absorptiometry measured BF% and lean muscle mass (LMM) at diagnosis, end of Induction, and end of Delayed Intensification. Sarcopenic obesity (gain in BF% with loss of LMM) was surprisingly common during ALL treatment, resulting in poor correlation between changes in BMI% (expressed as Z-score) and BF% overall (r = -0.05) and within patients (r = -0.09). BMI Z-score and BF% changed in opposite directions in >50% of interval assessments. While BMI% at diagnosis is a suitable predictor of obesity/BF% for epidemiological studies, change in BMI% (as expressed as Z-score) does not reflect body composition. Studies evaluating obesity in leukemia should consider using direct measures of body composition.

High Volume Exercise Training in Older Athletes Influences Inflammatory and Redox Responses to Acute Exercise

To examine whether the volume of previous exercise training in older athletes influences inflammatory, redox, and hormonal profiles, 40 trained marathon runners were divided into higher-volume (HVG, ∼480 min/week) and lower-volume groups (LVG, ∼240 min/week). Plasma inflammatory proteins, redox biomarkers, salivary testosterone, and cortisol were assessed at restand following two maximal acute exercise bouts. At rest, the LVG exhibited higher CRP, higher protein carbonyls, and lower SOD activity compared to the HVG (p's < .05). In response to exercise, TNF-α declined similarly in both groups whereas CRP increased differentially (+60% LVG; +24% HVG; p's < .05). Protein carbonyls decreased and thiols increased similarly in both groups, but SOD declined differentially between groups (-14% LVG; -20% HVG; p's < .05). Salivary testosterone decreased similarly in both groups, whereas cortisol did not change. A higher volume of training is associated with favorable inflammatory and redox profiles at rest, perhaps mediated by small inflammatory responses to acute exercise.

Better than counting seconds: Identifying fallers among healthy elderly using fusion of accelerometer features and dual-task Timed Up and Go

Devices and sensors for identification of fallers can be used to implement actions to prevent falls and to allow the elderly to live an independent life while reducing the long-term care costs. In this study we aimed to investigate the accuracy of Timed Up and Go test, for fallers’ identification, using fusion of features extracted from accelerometer data. Single and dual tasks TUG (manual and cognitive) were performed by a final sample (94% power) of 36 community dwelling healthy older persons (18 fallers paired with 18 non-fallers) while they wear a single triaxial accelerometer at waist with sampling rate of 200Hz. The segmentation of the TUG different trials and its comparative analysis allows to better discriminate fallers from non-fallers, while conventional functional tests fail to do so. In addition, we show that the fusion of features improve the discrimination power, achieving AUC of 0.84 (Sensitivity = Specificity = 0.83, 95% CI 0.62-0.91), and demonstrating the clinical relevance of the study. We concluded that features extracted from segmented TUG trials acquired with dual tasks has potential to improve performance when identifying fallers via accelerometer sensors, which can improve TUG accuracy for clinical and epidemiological applications.

Sensitivity and Specificity of Body Mass Index as a Marker of Obesity in Elderly Patients on Hemodialysis

OBJECTIVES

Diagnosing obesity by body mass index (BMI) may not be reliable in elderly individuals due to the changes in body composition. We aimed to analyze the accuracy of BMI thresholds by World Health Organization (WHO) and Nutrition Screening Initiative (NSI) to diagnose obesity in elderly patients on hemodialysis (HD).

DESIGN

Multicenter cross-sectional study.

SETTING

Six dialysis facilities.

SUBJECTS

169 elderly on chronic HD (70.4 ± 7.1 years; 63.9% men).

MAIN OUTCOME VARIABLE

Total body fat percentage (BF%) was assessed by the sum of skinfold thicknesses and abdominal fat by waist circumference (WC). Both were used as reference to test the specificity and sensitivity of BMI thresholds (WHO: ≥30 kg/m(2); NSI: >27 kg/m(2)).

RESULTS

The prevalence of obesity according to NSI-BMI, WHO-BMI, BF%, and WC thresholds were 31%, 13%, 27%, and 29.6% in men, respectively, and 36%, 15%, 13%, and 75% in women. Compared to BF%, the sensitivity of NSI-BMI was moderate (65.5%) for men and high (100%) for women, whereas that of WHO-BMI was low (31%) for men and high (87.5%) for women. Compared with WC, NSI-BMI had good (75%) sensitivity for men and moderate (47.8%) for women, whereas WHO-BMI had moderate (43.8%) sensitivity for men and low (19.6%) for women. The best agreement with BF% was observed for NSI-BMI in men (kappa = 0.46) and for WHO-BMI in women (kappa = 0.80). For WC, the best agreement was for WHO-BMI for men (kappa = 0.63) and NSI-BMI for women (kappa = 0.31).

CONCLUSIONS

BMI thresholds do not accurately diagnose adiposity in elderly on HD. Therefore, using BMI may lead to misclassifications in this segment population.

Fatores associados às complicações metabólicas e alimentação em idosos da zona rural

Resumo Este estudo objetivou avaliar fatores associados às complicações metabólicas e de alimentação em idosos da zona rural de Uberaba, Minas Gerais, norteados pelo Guia “10 passos para uma alimentação saudável para pessoas idosas” do Ministério da Saúde. Realizado inquérito domiciliar com 833 pessoas, 60 anos ou mais de idade, sem declínio cognitivo. Os dados foram coletados utilizando questionário de frequência alimentar, aferição de medidas antropométricas; submetidos à análise descritiva, taxa de prevalência e teste qui-quadrado (p < 0,05). As complicações metabólicas foram associadas ao sexo feminino (p = 0,001) e ao sobrepeso (p = 0,006). Mulheres se adequaram a cinco passos: número de refeições, ingestão adequada de leite e carnes magras, consumo reduzido de refrigerantes, doces e sal, prática de atividade física, não fumar e não ingerir bebida alcoólica; enquanto os homens seguiam três passos: consumo adequado de cereais, de arroz com feijão e de água. Idosos com menos de 80 anos aderiram mais ao consumo de água. Três passos se associaram ao peso normal, dois à classificação sem risco para complicações metabólicas e nenhum à escolaridade. Conclui-se que a dieta dos idosos rurais não está adequada às recomendações de alimentação saudável do Ministério da Saúde.

Comparison of body mass index (BMI) with the CUN-BAE body adiposity estimator in the prediction of hypertension and type 2 diabetes

Background

Obesity is a world-wide epidemic whose prevalence is underestimated by BMI measurements, but CUN-BAE (Clínica Universidad de Navarra - Body Adiposity Estimator) estimates the percentage of body fat (BF) while incorporating information on sex and age, thus giving a better match. Our aim is to compare the BMI and CUN-BAE in determining the population attributable fraction (AFp) for obesity as a cause of chronic diseases.

Methods

We calculated the Pearson correlation coefficient between BMI and CUN-BAE, the Kappa index and the internal validity of the BMI. The risks of arterial hypertension (AHT) and diabetes mellitus (DM) and the AFp for obesity were assessed using both the BMI and CUN-BAE.

Results

3888 white subjects were investigated. The overall correlation between BMI and CUN-BAE was R² = 0.48, which improved when sex and age were taken into account (R² > 0.90). The Kappa coefficient for diagnosis of obesity was low (28.7 %). The AFp was 50 % higher for DM and double for AHT when CUN-BAE was used.

Conclusions

The overall correlation between BMI and CUN-BAE was not good. The AFp of obesity for AHT and DM may be underestimated if assessed using the BMI, as may the prevalence of obesity when estimated from the percentage of BF.

The relationship between body mass index prior to old age and disability in old age

OBJECTIVES

To analyse the relationship between body mass index (BMI) in middle-age and disability status in old-age using data from the Melbourne Collaborative Cohort Study (MCCS).

METHODS

A total of 41 514 participants enroled in the MCCS between 1990-1994. Height and weight were measured at baseline and disability, defined as limitations to self-care activities of daily living (ADLs) and self-care plus mobility activities, was identified at follow-up (2003-2007). In all, 6300 participants were <65 years at baseline, 70 years at follow-up and not missing BMI at baseline or ADLs at follow-up. The association between BMI in six categories (BMI 18.5-22.5; 22.5-25; 25-27.5; 27.5-30; 30-35; 35+) and disability status was analysed using logistic regression. Models were stratified by sex, and sequentially adjusted for age, education, country of birth, then smoking, alcohol, fruit and vegetable intake, and physical activity.

RESULTS

Adjusted odds ratios for composite self-care ADL and mobility limitations compared with BMI 18.5-22.5 kg m(-2) were 1.73 (95%CI 1.14-2.64) for BMI 30-35 kg m(-2) and 3.46 (1.78-6.73) for BMI 35+ kg m(-2) in males. In females, adjusted odds ratios were 1.29 (1.00-1.68) for BMI 22.5-25 kg m(-2), 1.74 (1.35-2.24) for BMI 25-27.5 kg m(-2), 2.58 (1.98-3.36) for BMI 27.5-30 kg m(-2), 2.74 (2.10-3.58) for BMI 30-35 kg m(-2) and 4.21 (3.12-5.88) for BMI 35+ kg m(-2).

CONCLUSION

A graded relationship was observed between BMI and disability in males and females, across the continuum of BMI. These results highlight the importance of a healthy body weight at middle age in order to reduce the risk of disability in old age.