Varying Associations Between Body Mass Index and Physical and Cognitive Function in Three Samples of Older Adults Living in Different Settings

Relationship between nutritional status and clinical outcomes among older individuals using long-term care services: A systematic review and meta-analysis

BACKGROUND & AIMS

Nutritional status is a significant issue in an aging society; however, the impact of the nutritional status of older individuals using long-term care services on the caregiving burden remains unclear. This systematic review and meta-analysis aimed to investigate the impact of nutritional issues on adverse outcomes in older individuals using long-term care services.

METHODS

We used data from the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Web of Science, CINAHL, and Ichu-shi Web databases. Original articles published in English or Japanese between January 2000 and July 2022 were included. The inclusion criteria were interventional and observational studies on individuals using long-term care services with aged ≥65 years and a focus on body weight or weight loss. Data on adverse outcomes related to caregiving burden, including the number of people requiring care, mortality, complications, activities of daily living (ADL), and quality of life, were collected.

RESULTS

The literature search yielded 7873 studies, of which 35 were ultimately included. Seven observational studies investigated mortality outcomes, and seven examined ADL outcomes. The meta-analysis revealed significantly higher mortality rates in individuals classified as underweight (BMI <18.5 kg/m2) than in those with BMI ≥18.5 kg/m2 (risk ratio [RR] 1.49; 95 % confidence interval [CI] 1.31 to 1.73, 0.22; I2 93 %). Further, on categorising the participants based on a BMI cutoff of 25 kg/m2, those with a BMI of <25 kg/m2 had a significantly increased mortality rate (RR 1.21; 95 % CI 1.04-1.40; I2 = 98 %). BMI and weight loss did not affect ADL.

CONCLUSIONS

Our findings indicate that underweight and weight loss are significantly associated with increased mortality in older individuals using long-term care services. Therefore, appropriate weight management is recommended for this population. However, further research is necessary owing to the high heterogeneity observed in this study.

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 between body mass index, its change and cognitive impairment among Chinese older adults: a community-based, 9-year prospective cohort study

To examine the association of baseline body mass index (BMI) and BMI change with cognitive impairment among older adults in China. The study included data from the Chinese Longitudinal Healthy Longevity Study, a national community-based prospective cohort study from 2002 to 2018. Baseline BMI and BMI change were available for 12,027 adults aged older than 65 years. Cognitive impairment was defined as Chinese version of the Mini Mental State Examination score lower than 18. Multivariable Cox proportional hazard model was used. Among 12,027 participants (mean age was 81.23 years old and 47.48% were male), the proportion of underweight, normal, overweight and obese at baseline was 33.87%, 51.39%, 11.39% and 3.34%, respectively. During an average of 5.9 years' follow-up, 3086 participants (4.35 per 100 person-years) with incident cognitive impairment were identified. Compared with normal weight group, adjusted hazard ratio (AHR) for cognitive impairment was 0.86 (95% CI 0.75-0.99) among overweight group, whereas corresponding AHR was 1.02 (95% CI 0.94-1.10) in underweight and 1.01 (95% CI 0.80-1.28) in obese participants. Large weight loss (< -10%) was significantly associated with an increased risk of cognitive impairment (AHR, 1.42, 95% CI 1.29-1.56), compared to stable weight status group (-5% ~ 5%). In the restricted cubic spline models, BMI change showed a reverse J-shaped association with cognitive impairment. BMI-defined overweight, but not obesity, was associated with a lower risk of cognitive impairment among elderly Chinese adults, while large weight loss was associated with an increased risk. These findings are consistent with weight loss in the prodromal phase of dementia.

Body mass index and trajectories of cognitive decline among older Korean adults

Objectives: This study examined the relationship between body mass index (BMI) and trajectories of cognitive decline among older Korean adults.Methods: Participants were a nationally representative sample of 5126 Korean adults aged 60 or older from the Korean Longitudinal Study of Aging (KLoSA: 2006-2014). The main outcome variable, cognitive function, was measured with the Korean Mini-Mental State Examination (K-MMSE). According to the BMI values, respondents were divided into four groups at each wave: underweight (<18.5 kg/m²), healthy weight (18.5-22.9 kg/m²), overweight (23.0-24.9 kg/m²), and obese (≥25.0 kg/m²). Growth curve modeling was used to analyze the relationship of interest.Results: The growth curve modeling revealed that, regardless of BMI values, cognitive functioning declined as participants aged, and the rate of cognitive decline accelerated with age. After adjusting for all covariates, older Korean adults who were underweight displayed steeper declines in cognitive functioning, compared to those with a healthy weight. Conversely, overweight or obese older adults showed a much slower cognitive decline as they aged, after adjusting for covariates.Conclusion: Compared to people with a healthy BMI, people with a low BMI may be at risk for cognitive dysfunction, whereas a high BMI could function as a protective factor for cognitive dysfunction in older adulthood. Future research examining the mechanism for these trajectories are needed. Implications for research and clinical practice are discussed.

Early geriatric follow-up visits to nursing home residents reduce the number of readmissions: a quasi-randomised controlled trial

INTRODUCTION

Nursing home residents have a high risk of being readmitted after hospitalisation. The objective of this study is to test whether an early geriatric follow-up visit can reduce readmissions among nursing home residents without increasing mortality. The main components of the intervention will also be quantified.

MATERIALS AND METHOD

A quasi-randomised controlled design. A population of nursing-home residents aged 75 years or older admitted to hospital with one of nine medical diagnoses. All patients received comprehensive geriatric assessment before discharge. The intervention comprised a visit by a nurse and a doctor from a geriatric team the first weekday after discharge. Control group patients were offered a follow-up visit by their general practitioner 7-14 days after discharge.

RESULTS

Six hundred and forty-eight patients were included in the study between June 1st 2014 and December 15th 2016. In the intervention group, 13% were readmitted within 30 days after discharge, compared to 19% in the control group (p = 0.04). Adjusted hazard ratio = 0.63 (95% CI 0.42-0.95). The median length of hospital stay was 1 day for both groups. Neither 30 nor 90-day mortality were affected by the intervention. The most commonly registered intervention element was direct person-to-person contact between hospital and nursing home staff or relatives, followed by changes in medication and blood tests.

CONCLUSION

Early geriatric follow-up visits to recently discharged nursing home residents are a safe and effective way of reducing readmissions. Communication, changes in medication, and blood tests were the most frequently performed elements.