Obesity as a risk factor for developing functional limitation among older adults: A conditional inference tree analysis

Predicting functional dependency using machine learning among a middle-aged and older Chinese population

OBJECTIVE

To develop prediction models for assessing functional dependency in a middle-aged and older Chinese population.

METHOD

Adults ≥45 years old from the China Health and Retirement Longitudinal Study (CHARLS) and without functional dependency at baseline were included. Functional dependency was defined as needing any help in any basic activities of daily living (ADL) or instrumental activities of daily living (IADL). The outcomes were overall functional dependency, ADL and IADL dependency. Stacked ensemble models were constructed based on five selected machine learning models. Models were trained and tested in the 2011-2015 cohort, and were externally validated in the 2015-2018 cohort. SHapley Additive exPlanations (SHAP) was utilized to quantify the significance of predictors.

RESULT

In the training cohort, a total of 6,297 participants were included at baseline, 1,893 developed functional dependency during the follow-up period. The stacked ensemble model achieved the best performance in terms of discrimination ability for predicting overall functional dependency, ADL and IADL dependency, with AUCs of 0.750, 0.690 and 0.748, respectively; in external validation cohort, the corresponding AUCs were 0.725, 0.719 and 0.727, respectively. A compact model was further developed and maintained similar predictive performance.

CONCLUSION

The stacked ensemble approach can serve as a useful tool for identifying the risk of functional dependency in a large Chinese population. For ADL dependency, arthritis, age, self-report health, and waist circumference were identified as highly significant predictors. Conversely, cognitive function, age, living in rural areas, and performance in chair stand test emerged as highly ranked predictors for IADL dependency.

Associations between Serum Folate Concentrations and Functional Disability in Older Adults

Folate may have beneficial effects on physical function through its antioxidant effect. Thus, we investigated the associations between serum folate and functional disability in older adults. Data from the National Health and Nutrition Examination Survey 2011–2018 were used. Serum folate included 5-methyltetrahydrofolate and total folate. Five domains of functional disability, including lower extremity mobility (LEM), instrumental activities of daily living (IADL), activities of daily living (ADL), leisure and social activities (LSA), and general physical activities (GPA), were self-reported. Multivariable-adjusted logistic regression models and restricted cubic splines were employed. 5-Methyltetrahydrofolate was inversely associated with IADL and GPA disability, and the multivariate-adjusted ORs (95% CIs) in the highest versus lowest quartiles were 0.65 (0.46–0.91) and 0.70 (0.50–0.96), respectively. The total folate was also inversely associated with IADL (OR quartile 4vs1 = 0.65, 95% CI: 0.46–0.90) and GPA (OR quartile 3vs1 = 0.66, 95% CI: 0.44–0.99) disability. The dose–response relationships showed a gradual decrease in the risk of IADL and GPA disability as serum folate increased. In the sex, age, BMI, and alcohol consumption subgroup analyses, we saw that the associations were primarily found in females, under 80 years old, normal weight, and non-drinkers. Sensitivity analyses further confirmed the robustness of our results. Our results indicated that serum folate concentrations were negatively associated with IADL and GPA disability, especially in females. In other subgroup analyses, we discovered that these negative associations were primarily prevalent in participants under 80 years old, normal weight, and non-drinkers.

Health-related factors leading to disabilities in Korea: Survival analysis

The purpose of this study is to analyze (a) population and socioeconomic factors affecting disability, excluding the occurrence of disability due to accidents and congenital diseases, and (b) health-related behavioral factors and factors that can prevent and reduce the cause of disability due to disease in Korea. This study was a longitudinal research. Data were obtained from The 2018 Korean Health Panel (KHP) is a survey jointly conducted by the Korea Institute of Health and Social Affairs and the National Health Insurance Service. A total of 7, 372 (Mage = 52.14, SD = 21.39; Male = 47.52%) were analyzed in this study. People with Higher education attainments and more income levels were associated with lower hazard of developing new disabilities (all p < 0.05). In this study, the health factors that could be related to the occurrence of new disabilities were smoking, alcohol consumption, physical activity, and stress (all p < 0.0001). However, physical activity was negatively associated with the risk of developing a disability at all follow-ups (p < 0.05). Higher scores on the number of chronic diseases (valid scores = 0, 1, 2, 3, or more) represented a greater level of newly developing disability present at all follow-ups (all p < 0.0001). This longitudinal study confirmed the relationship between health-related factors and specific chronic diseases. Its findings can be used as a crucial foundation for establishing healthcare policies and services that can lower and prevent disability by preventing and reducing specific negative health behaviors and unhealthy behavioral factors, and alleviating chronic diseases in Korea.

Association between body mass index, multi-morbidity and activities of daily living among New Zealand nursing home older adults: a retrospective analysis of nationwide InterRAI data

Background

Obesity is a well-established risk factor for multi-morbidity and disability among older adults in the community and acute care settings. However, nursing home residents with body mass index (BMI) below 18.5 kg/m² and above 25.0 kg/m² have been understudied. We examined the prevalence of multi-morbidity and disability in activities of daily living (ADL) by BMI category and further investigated the association between BMI, multi-morbidity, and disability of ADL in a large cohort of older adults in nursing homes in New Zealand.

Methods

A retrospective review of nursing home residents’ data obtained from the New Zealand International Resident Assessment Instrument national dataset from 2015 to 2018. One hundred ninety-eight thousand seven hundred ninety older adults (≥60 years) living in nursing homes were included. BMI was calculated as weight in kilograms (kg) divided by height in meters squared (m²). Multimorbidity was defined as the presence of ≥2 health conditions. The risk of disability was measured by a 4-item ADL self-performance scale. The prevalence ratio (PR) of the association between BMI and multi-morbidity and between BMI and disability in ADL was assessed using Poisson regression with robust variance.

Results

Of the 198,790 residents, 10.6, 26.6, 11.3 and 5.4% were underweight, overweight, obese, and extremely obese, respectively. 26.4, 31.3 and 21.3% had one, two and three disease conditions, respectively, while 14.3% had four or more conditions. 24.1% could perform only one ADL, and 16.1% could perform none. The prevalence of multi-morbidity increased with increasing BMI, whereas mean disability in ADL decreased with increasing BMI. The risk of multi-morbidity was higher for the overweight (PR, 95%CI: 1.03, 1.02–1.03) and obese (PR, 95% CI: 1.07, 1.06–1.08) compared to normal weight after controlling for age, sex, ethnicity, and region. BMI was inversely associated with mean ADL; β, 95% CI for overweight (− 0.30, − 0.32, − 0.28) and obese − 0.43, − 0.45, − 0.40 compared to normal weight.

Conclusion

Being underweight was associated with a decline in the performance of ADL in nursing home residents. In contrast, being overweight and obese positively affected functional performance, demonstrating that the obesity paradox plays an important role in this population. The observed associations highlight areas where detection and management of underweight and healthy aging initiatives may be merited.

Association of lung function with functional limitation in older adults: A cross-sectional study

INTRODUCTION

Impaired lung function is independently associated with higher rates of disability, however, few studies have examined the association between lung function and functional limitation. This study aimed to assess this association and dose-response relationship in older adults.

METHODS

Data from the National Health and Nutrition Examination Survey (2007-2012) was used as a cross-sectional study. Lung function was determined by Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Functional limitation in older adults was identified by six self-reported questions on physical function. 3070 adults aged 60 and over were enrolled in our study. Logistic regression models and restricted cubic spline models were applied to examine the association between lung function and the risk of functional limitation.

RESULTS

FEV1 and FVC were inversely associated with the risk of functional limitation. In the full adjusted model, compared with the lowest tertile of FEV1, the odds ratios (95% confidence intervals) of functional limitation for tertile 2 and tertile 3 were 0.5422 (0.3848-0.7639) and 0.4403 (0.2685-0.7220), and the odds ratios (95% confidence intervals) of functional limitation for tertile 2 and tertile 3 of FVC were 0.5243 (0.3503-0.7848) and 0.3726 (0.2072-0.6698). Furthermore, an inverse association persisted after stratified analysis by gender and sensitivity analysis. Dose-response analyses showed that the odds of functional limitation declined with increase in FEV1 and FVC in a nonlinear manner.

CONCLUSIONS

Lung function was inversely associated with functional limitation among older adults.

Conditional inference trees in the assessment of tree mortality rates in the transitional mixed forests of Atlantic Canada

Long-term predictions of forest dynamics, including forecasts of tree growth and mortality, are central to sustainable forest-management planning. Although often difficult to evaluate, tree mortality rates under different abiotic and biotic conditions are vital in defining the long-term dynamics of forest ecosystems. In this study, we have modeled tree mortality rates using conditional inference trees (CTREE) and multi-year permanent sample plot data sourced from an inventory with coverage of New Brunswick (NB), Canada. The final CTREE mortality model was based on four tree- and three stand-level terms together with two climatic terms. The correlation coefficient (R²) between observed and predicted mortality rates was 0.67. High cumulative annual growing degree-days (GDD) was found to lead to increased mortality in 18 tree species, including Betula papyrifera, Picea mariana, Acer saccharum, and Larix laricina. In another ten species, including Abies balsamea, Tsuga canadensis, Fraxinus americana, and Fagus grandifolia, mortality rates tended to be higher in areas with high incident solar radiation. High amounts of precipitation in NB’s humid maritime climate were also found to contribute to heightened tree mortality. The relationship between high GDD, solar radiation, and high mortality rates was particularly strong when precipitation was also low. This would suggest that although excessive soil water can contribute to heightened tree mortality by reducing the supply of air to the roots, occasional drought in NB can also contribute to increased mortality events. These results would have significant implications when considered alongside regional climate projections which generally entail both components of warming and increased precipitation.

Mortality in the USA, the UK and Other Western Countries, 1989-2015: What Is Wrong With the US?

This population-based study compares U.S. effectiveness with 20 Other Western Countries (OWC) in reducing mortality 1989-1991 and 2013-2015 and, responding to criticisms of Britain's National Health Service, directly compares U.S. with U.K. child (0-4), adult (55-74), and 24 global mortality categories. World Health Organization Age-Standardized Death Rates (ASDR) data are used to compare American and OWC mortality over the period, juxtaposed against national average percentages of Gross Domestic Product (GDP) Expenditure on Health (%GDPEH) drawn from World Bank data. America's average %GDPEH was highest at 13.53% and Britain's the lowest at 7.68%. Every OWC had significantly greater ASDR reductions than America. Current U.S. child and adult mortality rates are 46% and 19% higher than Britain's. Of 24 global diagnostic mortalities, America had 16 higher rates than Britain, notably for Circulatory Disease (24%), Endocrine Disorders (70%), External Deaths (53%), Genitourinary (44%), Infectious Disease (65%), and Perinatal Deaths (34%). Conversely, U.S. rates were lower than Britain's for Neoplasms (11%), Respiratory (12%), and Digestive Disorder Deaths (11%). However, had America matched the United Kingdom's ASDR, there would have been 488,453 fewer U.S. deaths. In view of American %GDPHE and their mortality rates, which were significantly higher than those of the OWC, these results suggests that the U.S. health care system is the least efficient in the Western world.

Disability assessment in an Italian cohort of patients with obesity using an International Classification of Functioning, Disability and Health (ICF)-derived questionnaire

BACKGROUND

Obesity is a clinical condition that contributes to the development of related disability in different areas (physical, psychological and social). Multidisciplinary treatment calls for specific instruments able to evaluate all related functional problems. We have developed a tool (an ICF-based assessment instrument, the ICF-OB schedule) to evaluate obesity-related disability, composed of an inventory of 71-items from the WHO International Classification of Functioning, Disability and Health (ICF).

AIM

The aim of the present study was to validate this new tool for the definition of obesity-related disability. We also sought to examine the relationship between obesity disability, an index of multimorbidity (Cumulative Illness Rating Scale [CIRS]) and a well-validated score of perceived obesity-related disability (Italian Obesity Society Test for Obesity-Related Disability [TSD-OC]).

DESIGN

Process validation of the ICF-OB schedule.

SETTING

Baseline conditions of out- and in-patients.

POPULATION

A large cohort of obese patients recruited from 9 multidisciplinary centers belonging to the Italian Obesity Society (SIO) network, which provide specialized obesity care.

METHODS

A total of 353 patients (F: 70%, age: 50.2±12.7yrs, BMI: 41.4±8.3kg/m²) were enrolled between January 2017 and June 2018. The ICF-OB was used to define patients' functioning and disability profiles in order to set and appraise rehabilitation goals.

RESULTS

We described the distribution of body functions (BF), body structures (BS) and activities and participations (A&P) categories and the agreement rates were significant for the majority of these. The ICF-OB was more often significantly associated, and with stronger coefficients, with patients' comorbidities as described by the CIRS rather than with Body Mass Index (BMI). The TSD-OC also presented a strong association with A&P indexes.

CONCLUSIONS

The complexity of clinical condition, that generates disability in obesity might be well identified with the use of this new instrument that appear significant related to the perceived disability for each patients and also with their multimorbidity.

CLINICAL REHABILITATION IMPACT

The ICF-OB shows great promise as a tool for goal setting in the rehabilitation of obese patients.

A systematic review shows no performance benefit of machine learning over logistic regression for clinical prediction models

OBJECTIVES

The objective of this study was to compare performance of logistic regression (LR) with machine learning (ML) for clinical prediction modeling in the literature.

STUDY DESIGN AND SETTING

We conducted a Medline literature search (1/2016 to 8/2017) and extracted comparisons between LR and ML models for binary outcomes.

RESULTS

We included 71 of 927 studies. The median sample size was 1,250 (range 72-3,994,872), with 19 predictors considered (range 5-563) and eight events per predictor (range 0.3-6,697). The most common ML methods were classification trees, random forests, artificial neural networks, and support vector machines. In 48 (68%) studies, we observed potential bias in the validation procedures. Sixty-four (90%) studies used the area under the receiver operating characteristic curve (AUC) to assess discrimination. Calibration was not addressed in 56 (79%) studies. We identified 282 comparisons between an LR and ML model (AUC range, 0.52-0.99). For 145 comparisons at low risk of bias, the difference in logit(AUC) between LR and ML was 0.00 (95% confidence interval, -0.18 to 0.18). For 137 comparisons at high risk of bias, logit(AUC) was 0.34 (0.20-0.47) higher for ML.

CONCLUSION

We found no evidence of superior performance of ML over LR. Improvements in methodology and reporting are needed for studies that compare modeling algorithms.

Optimal Protein Intake during Weight Loss Interventions in Older Adults with Obesity

Obesity rates in people 60 years and older are increasing. While obesity is linked with detrimental health risks, weight loss in this population has previously been considered controversial due to potential worsening of age-related sarcopenia. Protein intake during energy restriction has been linked to lean body mass preservation. No formal guidelines for optimal protein intake during structured weight loss interventions exist for this population, but it appears that the current Recommended Dietary Allowance of 0.8 grams per kilogram of body weight per day may be inadequate. The purpose of this review is to discuss optimal protein intake during structured weight loss interventions in persons 60 years and older with obesity and to present a framework for guidelines to be used by health professionals focusing on weight loss interventions in older adults. Goals for the amount, source, and timing of protein intake, from both food and supplements, are presented and discussed.

The impact of body mass index on metatarsalgia surgical outcomes

INTRODUCTION

Several studies have suggested that an increased body mass index (BMI) is a negative factor for forefoot plantar pain but its influence in the surgical correction of metatarsalgia is unknown. The purpose of the present study is to evaluate the influence of the BMI on the surgical outcomes of metatarsalgia. It has been hypothesized that the higher the BMI, the worse the functional outcomes after metatarsalgia surgical treatment at one year follow-up.

MATERIAL AND METHODS

A prospective cohort study that included all patients operated on for third rocker metatarsalgia was conducted. Weil's osteotomy was performed on all the patients operated on. The patients' pre-operative height, weight, and BMI were recorded. The patients were subsequently divided into three groups based on their BMI. There was group 1 or the normal group (18.5 > BMI ≤ 25 kg/m2), group 2 or the overweight group (25 > BMI ≤ 30 kg/m2), and group 3 or the obese group (BMI > 30 kg/m2). Pre-operative, post-operative, and differential AOFAS were used to evaluate and compare the groups. The post-operative VAS was also measured to assess pain. The correlation between the BMI and those variables was also analyzed.

RESULTS

After the exclusion criteria were applied, 107 patients were finally assessed. There were 22 patients (20.6%) in group 1, 52 patients (48.6%) in group 2, and 33 patients (30.8%) in group 3. No correlation was observed between the BMI and AOFAS (p > 0.05). Neither were any differences found when the three groups were compared (p > 0.05). Moreover, no correlation between the BMI and the VAS score was observed (p = 0.690).

CONCLUSION

Obesity does not negatively influence functional outcomes after surgery for metatarsalgia in short to medium term. Regardless of their BMI, patients with propulsive metatarsalgia improve in functionality after surgical treatment.