The effect of obesity on incidence of disability and mortality in Mexicans aged 50 years and older

Comparison of body fat percentage assessments by bioelectrical impedance analysis, anthropometrical prediction equations, and dual-energy X-ray absorptiometry in older women

Background

Individuals with high body fat have a higher risk of mortality. Numerous anthropometric-based predictive equations are available for body composition assessments; furthermore, bioelectrical impedance analysis (BIA) estimates are available. However, in older adults, the validity of body fat estimates requires further investigation.

Objective

To assess the agreement between percentage body fat (BF%) estimates by BIA and five predictive equations based on anthropometric characteristics using dual X-ray absorptiometry (DXA) as reference method. A secondary objective was to identify whether excluding short-stature women improves the agreement of BF% estimates in a group of community-dwelling, older Mexican women.

Methods

A concordance analysis of BF% was performed. A total of 121 older women participated in the study. Anthropometric information, BIA, and DXA body composition estimates were obtained. Five equations using anthropometric data were evaluated in order to determine body fat percentage (BF%) using DXA as reference method. Paired t-test comparisons and standard error of estimates (SEE) were obtained. The Bland-Altman plot with 95% limits of agreement and the concordance correlation coefficient (CCC) were used to evaluate the BF% prediction equations and BIA estimates.

Results

The mean age of the study participants was 73.7 (±5.8) years old. BIA and the anthropometric based equations examined showed mean significant differences when tested in the entire sample. For the taller women (height > 145 cm), no significant difference in the paired comparison was found between DXA and BIA of BF% estimates. The mean BF% was 40.3 (±4.8) and 40.7 (±6.2) for DXA and BIA, respectively. The concordance between methods was good (CCC 0.814), (SEE 2.62). Also, in the taller women subset, the Woolcott equation using waist-to-height ratio presented no significant difference in the paired comparison; however, the error of the estimates was high (SEE 3.37) and the concordance was moderate (CCC 0.693).

Conclusion

This study found that BIA yielded good results in the estimation of BF% among women with heights over 145 cm. Also, in this group, the Woolcott predictive equation based on waist circumference and height ratio showed no significant differences compared to DXA in the paired comparison; however, the large error of estimates observed may limit its application. In older women, short stature may impact the validity of the body fat percentage estimates of anthropometric-based predictive equations.

Imputation of Non-Response in Height and Weight in the Mexican Health and Aging Study

The way missing data in population surveys are treated can influence research results. Therefore, the aim of this paper is to explain the reasons and procedure for imputing anthropometric data such as height and weight self-reported by individuals in the first four waves of the Mexican Health & Aging Study (MHAS). We highlight the effect of the imputation versus the exclusion of the cases with missing data, by comparing the distribution of these values and their associated effects on the Body Mass Index using a regression model. We conclude that the incorporation of imputed data offers more solid results compared with elimination the cases with missing data. Hence the importance of applying these statistical procedures, with appropriate treatment of the data, making the methodology and the imputed data available to the users by the same source of information, as offered in the MHAS.

[Functional dependence and support for the older persons in Mexico, 2001-2026Dependência funcional e apoio em idosos no México, 2001-2026]

Objectives

Identify the factors associated with future functional dependence in the elderly in Mexico and with receiving or not receiving support for basic activities of daily living (ADLs); and project the prevalence of functional dependence in 2026.

Methods

Data from the 2001 National Health and Aging Study (ENASEM) and from the 2012 and 2015 follow-up rounds were used. A multinomial logistic regression model was used to analyze factors associated with future dependence, and a logistic regression model was used for factors associated with receiving or not support. The projected number of older persons with functional dependence in 2026 was based on data from the 2015 ENASEM and on estimated rates from the model of future dependence.

Results

Older people, those with a lower educational level, those with hypertension, arthritis, or diabetes, those who had suffered a stroke or fall, and those with some degree of prior functional dependence had a significantly higher risk of mild or severe dependence and death within 11 years, compared to the reference group. Older people and those with severe dependence had higher odds of receiving support compared to reference groups. By 2026, it is estimated that 18.9% of older people in Mexico will have mild dependence and 9.3% will be severely dependent.

Conclusions

Factors associated with future dependence and death were age, educational level, certain chronic diseases, having fallen, and having prior functional dependence; the factors associated with receiving support for basic ADLs were severe dependence and age. It is estimated that the prevalence of dependence will increase 2.1 times over 25 years (2001-2026).

Incidence Rates of Disability and Its Associated Factors among Korean Community-Dwelling Older Adults

BACKGROUND

We aimed to identify incidence rates of disability and its associated factors among Korean community-dwelling older adults.

METHODS

The sample included 1,739 Koreans aged over 65 yr from the Korean Longitudinal Study of Aging (2006-2016) who reported no limitations in activities of daily living (ADL) or instrumental activities of daily living (IADL) at baseline (2006) and had complete data for other covariates. ADL, IADL, socio-demographic, lifestyle, and health-condition data were collected and analyzed using multiple logistic regression models.

RESULTS

The 10-yr incidence rates of ADL and IADL disability in subjects with no disability at baseline were 11.6% and 21.6%, respectively. After adjusting for socio-demographic, lifestyle, and health-condition factors, the incidence of ADL disability was higher in women (odds ratio [OR] =1.418, 95% confidence interval [CI]=1.102-2.613) and increased with age (OR=1.170, 95% CI=1.133-1.208), multi-morbidity (OR=1.194, 95% CI=1.015-1.406), and obesity (OR=1.563, 95% CI=1.057-2.311). It decreased in subjects living alone (OR=0.531, 95% CI=0.328-0.856). The incidence of IADL disability increased with age (OR=1.131, 95% CI=1.102-1.161), multi-morbidity (OR=1.199, 95% CI=1.054-1.365), and cognitive disability (OR=1.422, 95% CI=1.083-1.866) and decreased for subjects living alone (OR=0.484, 95% CI=0.328-0.715) and with overweight (OR=0.725, 95% CI=0.532-0.988).

CONCLUSION

Incidence rates of disability differed considerably based on socio-demographic, lifestyle, and health-condition factors. These results suggest the importance of identifying factors that can decrease the risk of disability in this group and of prevention efforts in populations with a higher disability risk.

Body mass index and all-cause mortality in older adults: A scoping review of observational studies

In older age, body composition changes as fat mass increases and redistributes. Therefore, the current body mass index (BMI) classification may not accurately reflect risk in older adults (65+). This study aimed to review the evidence on the association between BMI and all-cause mortality in older adults and specifically, the findings regarding overweight and obese BMI. A systematic search of the OVID MEDLINE and Embase databases was conducted between 2013 and September 2018. Observational studies examining the association between BMI and all-cause mortality within a community-dwelling population aged 65+ were included. Seventy-one articles were included. Studies operationalized BMI categorically (n = 60), continuously (n = 8) or as a numerical change/group transition (n = 7). Reduced risk of mortality was observed for the overweight BMI class compared with the normal BMI class (hazard ratios [HR] ranged 0.41-0.96) and for class 1 or 2 obesity in some studies. Among studies examining BMI change, increases in BMI demonstrated lower mortality risks compared with decreases in BMI (HR: 0.83-0.95). Overweight BMI classification or a higher BMI value may be protective with regard to all-cause mortality, relative to normal BMI, in older adults. These findings demonstrate the potential need for age-specific BMI cut-points in older adults.

Association between obesity status and successful aging among older people in China: evidence from CHARLS

Background

The paper aimed to examine the association between obesity status and successful aging among elderly adults in China and further find gender differences in the effect of components of successful aging on obesity status.

Methods

The data came from the follow-up survey(2015) of China Health and Retirement Longitudinal Study (CHARLS) and 4019 dwellers age 60 and over are included. Obesity status were defined by the body mass index (BMI) according to Chinese criteria. Successful aging was defined following Rowe and Kahn’s multidimensional model. Multivariable logistic regression was used to estimate the relationship between obesity status and successful aging.

Results

The rate of successful aging in men and women was 18.87 and 9.48% respectively. For BMI, the proportion of population with underweight, overweight and obesity in men was 10.29, 23.04 and 29.63% respectively and that in women was 1.40, 11.69 and 9.47%. Men with obesity (OR = 1.587 95% CI 1.087 ~ 2.316) has an positive relationship with successful aging than normal weight men; Women with underweight (OR = 0.197 95% CI 0.058 ~ 0.824) has an negative relationship with successful aging than normal weight women; Meanwhile, no matter men and women, the relationship between obesity status and successful aging were not significant among oldest adults(≥75 years).

Conclusion

Obesity status was significantly association with successful aging in young older adults (60-74 years), and the components of successful aging differently were related with the obesity status of male and female.

Gait speed moderates the adverse effect of obesity on dependency in older Colombian adult

INTRODUCTION

Gait speed worsens with the presence of obesity, and is a powerful marker of functional dependence. Accordingly, gait speed could be a factor that improves or worsens the relationship between obesity and dependence in activities of daily living (ADL). However, to date this potential role has not been examined and the minimum gait speed threshold in the relationship between obesity and ADL is not known. The aim of this study was to determine whether speed moderates the association between obesity and dependence in ADL, and also define the gait speed threshold of this relationship.

METHODS

A total of 20,507 community-dwelling older adults from a cross-sectional analysis of national survey data - the Colombian Health, Well-being and Aging study (SABE, 2015) - were surveyed. The research data were collected using structured questionnaires, including basic information, ADL measured using the Barthel Index, body mass index, and gait speed (3 m). The Johnson-Neyman technique was applied to determine the gait speed threshold adjusted for age, sex and comorbidities.

RESULTS

Regression analysis showed a significant detrimental effect of obesity on dependence in ADL, which was moderated by gait speed (β = 0.081; 95%CI: 0.045 to 0.117; p < 0.001). Adjusted for major covariates, the Johnson-Neyman technique defined two gait speed thresholds: < 0.77 m/s, indicating an aggravated adverse effect; and >1.06 m/s, indicating a positive effect.

CONCLUSIONS

The adverse effect of obesity on dependence in ADL is moderated by gait speed. Considering these thresholds, the distribution of older adults in each of the proposed areas of significance were: below 0.77 (m/s) = 14,324 (70.0%), above 1.06 (m/s) = 1553 older adults (7.5%) and between areas = 4630 older adults (22.5%).

Diversity in the Factors Associated with ADL-Related Disability among Older People in Six Middle-Income Countries: A Cross-Country Comparison

The low- and middle-income countries (LMICs) are experiencing rapid population ageing, yet knowledge about disability among older populations in these countries is scarce. This study aims to identify the prevalence and factors associated with disability among people aged 50 years and over in six LMICs. Cross-sectional data from the World Health Organization (WHO) Study on global AGEing and adult health Wave 1 (2007-2010) in China, Ghana, India, Mexico, the Russian Federation, and South Africa was used. Multivariable logistic regression analyses were undertaken to examine the association between sociodemographic factors, health behaviours, chronic conditions, and activities of daily living (ADL) disability. The prevalence of disability among older adults ranged from 16.2% in China to 55.7% in India. Older age, multimorbidity, and depression were the most common factors related to disability in all six countries. Gender was significant in China (OR = 1.14, 95% CI: 1.01-1.29), Ghana (OR = 1.22, 95% CI: 1.01-1.48) and India (OR = 1.65, 95% CI: 1.37-1.99). Having no access to social capital was significantly associated with ADL disability in China (OR = 2.57, 95% CI: 1.54-4.31) and South Africa (OR = 4.11, 95% CI: 1.79-9.43). Prevalence data is valuable in these six ageing countries, with important evidence on mitigating factors for each. Identifying determinants associated with ADL disability among older people in LMICs can inform how to best implement health prevention programmes considering different country-specific factors.

Diversity and signature of small RNA in different bodily fluids using next generation sequencing

BACKGROUND

Small RNAs are critical components in regulating various cellular pathways. These molecules may be tissue-associated or circulating in bodily fluids and have been shown to associate with different tumors. Next generation sequencing (NGS) on small RNAs is a powerful tool for profiling and discovery of microRNAs (miRNAs).

RESULTS

In this study, we isolated total RNA from various bodily fluids: blood, leukocytes, serum, plasma, saliva, cell-free saliva, urine and cell-free urine. Next, we used Illumina's NGS platform and intensive bioinformatics analysis to investigate the distribution and signature of small RNAs in the various fluids. Successful NGS was accomplished despite the variations in RNA concentrations among the different fluids. Among the fluids studied, blood and plasma were found to be the most promising fluids for small RNA profiling as well as novel miRNA prediction. Saliva and urine yielded lower numbers of identifiable molecules and therefore were less reliable in small RNA profiling and less useful in predicting novel molecules. In addition, all fluids shared many molecules, including 139 miRNAs, the most abundant tRNAs, and the most abundant piwi-interacting RNAs (piRNAs). Fluids of similar origin (blood, urine or saliva) displayed closer clustering, while each fluid still retains its own characteristic signature based on its unique molecules and its levels of the common molecules. Donor urine samples showed sex-dependent differential clustering, which may prove useful for future studies.

CONCLUSIONS

This study shows the successful clustering and unique signatures of bodily fluids based on their miRNA, tRNA and piRNA content. With this information, cohorts may be differentiated based on multiple molecules from each small RNA class by a multidimensional assessment of the overall molecular signature.

Body mass index and the risk of incident functional disability in elderly Japanese: The OHSAKI Cohort 2006 Study

The relationship between the body mass index (BMI) and the incidence of cause-specific disability remains unclear.We conducted a prospective cohort study of 12,376 Japanese individuals aged ≥65 years who were followed up for 5.7 years. Information on BMI and other lifestyle factors was collected via a questionnaire in 2006. Functional disability data were retrieved from the public Long-term Care Insurance database. BMI was divided into 6 groups (<21, 21-<23, 23-<25, 25-<27[reference], 27-<29 and ≥29). Hazard ratios and 95% confidence intervals for cause-specific disability were estimated using Cox proportional hazards regression models.A U-shaped relationship between BMI and functional disability was observed, with a nadir at 26. The nadir BMI values with the lowest disability risk were 28 for dementia, 25 for stroke, and 23 for joint disease. A low BMI (<23) was a risk factor for disability due to dementia, the HR values (95% CI) being 2.48 (1.70-3.63) for BMI <21 and 2.25 (1.54-3.27) for BMI 21 to <23; a high BMI (≥29) was a risk factor for disability due to joint disease, the HR value (95% CI) being 2.17 (1.40-3.35). There was no significant relationship between BMI and disability due to stroke.The BMI nadirs for cause-specific disability differed: a low BMI (<23) was a risk factor for disability due to dementia, and a high BMI (≥29) was a risk factor for disability due to joint disease. Because BMI values of 23 to <29 did not pose a significantly higher risk for each cause of disability, this range should be regarded as the optimal one for the elderly population.

Muscle Weakness Is Associated With Diabetes in Older Mexicans: The Mexican Health and Aging Study

BACKGROUND

The risk of cardiovascular problems due to diabetes mellitus is highest among older Mexicans, and yet what remains to be determined is the association between muscle weakness and diabetes in this population. Therefore, the purpose of this study was to determine the association between muscle strength and diabetes among Mexican adults greater than 50 years of age.

DESIGN

Cross-sectional.

SETTING

National sample of households in both urban and rural areas.

PARTICIPANTS

A subsample of 1841 individuals aged 50 years and older was included from the 2012 Mexican Health and Aging Study.

MEASUREMENTS

Strength was assessed using a hand-held dynamometer, and the single largest reading from either hand was normalized to body mass (normalized grip strength [NGS]). Conditional inference tree analyses were used to identify sex-specific NGS weakness thresholds. Linear regression was used to examine the association between NGS and HbA1c, and logistic regression was used to assess the association between weakness and risk of diabetes (HbA1c ≥ 6.5% [≥48 mmol/mol]), after controlling for age, sex, and waist circumference.

RESULTS

NGS was inversely associated with HbA1c (β = -1.56; P < .001). Optimal sex-specific NGS weakness thresholds to detect diabetes were ≤0.46 and ≤0.30 for men and women, respectively. Weakness was associated with significantly increased odds of diabetes (odds ratio, 1.69; 95% confidence interval, 1.37-2.10), even after adjusting for age, sex, and waist circumference.

CONCLUSIONS

NGS was robustly associated with diabetes and other cardiometabolic risk factors in older Mexicans. This simple screen may serve as a valuable tool to identify adults that are at risk for negative health consequences or early mortality and who might benefit from lifestyle interventions to reduce risk.

BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants

OBJECTIVE

To conduct a systematic review and meta-analysis of cohort studies of body mass index (BMI) and the risk of all cause mortality, and to clarify the shape and the nadir of the dose-response curve, and the influence on the results of confounding from smoking, weight loss associated with disease, and preclinical disease.

DATA SOURCES

PubMed and Embase databases searched up to 23 September 2015.

STUDY SELECTION

Cohort studies that reported adjusted risk estimates for at least three categories of BMI in relation to all cause mortality.

DATA SYNTHESIS

Summary relative risks were calculated with random effects models. Non-linear associations were explored with fractional polynomial models.

RESULTS

230 cohort studies (207 publications) were included. The analysis of never smokers included 53 cohort studies (44 risk estimates) with >738 144 deaths and >9 976 077 participants. The analysis of all participants included 228 cohort studies (198 risk estimates) with >3 744 722 deaths among 30 233 329 participants. The summary relative risk for a 5 unit increment in BMI was 1.18 (95% confidence interval 1.15 to 1.21; I(2)=95%, n=44) among never smokers, 1.21 (1.18 to 1.25; I(2)=93%, n=25) among healthy never smokers, 1.27 (1.21 to 1.33; I(2)=89%, n=11) among healthy never smokers with exclusion of early follow-up, and 1.05 (1.04 to 1.07; I(2)=97%, n=198) among all participants. There was a J shaped dose-response relation in never smokers (Pnon-linearity <0.001), and the lowest risk was observed at BMI 23-24 in never smokers, 22-23 in healthy never smokers, and 20-22 in studies of never smokers with ≥20 years' follow-up. In contrast there was a U shaped association between BMI and mortality in analyses with a greater potential for bias including all participants, current, former, or ever smokers, and in studies with a short duration of follow-up (<5 years or <10 years), or with moderate study quality scores.

CONCLUSION

Overweight and obesity is associated with increased risk of all cause mortality and the nadir of the curve was observed at BMI 23-24 among never smokers, 22-23 among healthy never smokers, and 20-22 with longer durations of follow-up. The increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. Lack of exclusion of ever smokers, people with prevalent and preclinical disease, and early follow-up could bias the results towards a more U shaped association.