Early life factors as predictors of age-associated deficit accumulation across 17 years from midlife into old age

Spousal education and frailty levels among Chinese older adults: A national longitudinal study

Background

Prior research has identified one's own education level as a risk factor for frailty. However, the association between spousal education and frailty in later life is uncertain. We aim to examine the longitudinal association between spousal education and frailty levels among Chinese older populations.

Methods

3856 participants aged 60 and older from the 2011-2018 China Health and Retirement Longitudinal Study were analyzed. A 54-item deficit cumulative frailty index was developed to evaluate frailty levels at each follow-up. Linear mixed-effects models were used to examine the longitudinal association of spousal education with frailty levels, and whether this association varied by sex and own education level.

Results

Higher spouse education was associated with lower frailty levels, and this association decreased with age. Compared with older adults whose spouses had no formal education, older adults whose spouses had less than middle school education had an 8.82 lower level of frailty (95% CI: 15.05 to -2.58, P < 0.01); those with spouses with middle school education and above had a 23.44 lower level (95% CI: 31.43 to -15.44, P < 0.001). Stratified analysis showed that every additional year of spouse education was also associated with lower frailty levels in non-frail participants at baseline, but stronger among those already frail. The association between high spousal education and lower frailty did not vary by sex or own education.

Conclusion

This study reveals a significant association between having a more educated spouse and lower later-life frailty levels for both older men and women, regardless of one's own educational background. It emphasizes the importance of leveraging educated spouses to prevent and manage frailty.

Mendelian randomization shows causal effects of birth weight and childhood body mass index on the risk of frailty

Background

The association between birth weight and childhood body mass index (BMI) and frailty has been extensively studied, but it is currently unclear whether this relationship is causal.

Methods

We utilized a two-sample Mendelian randomization (MR) methodology to investigate the causal effects of birth weight and childhood BMI on the risk of frailty. Instrumental variables (p < 5E-08) strongly associated with own birth weight (N = 298,142 infants), offspring birth weight (N = 210,267 mothers), and childhood BMI (N = 39,620) were identified from large-scale genomic data from genome-wide association studies (GWAS). The frailty status was assessed using the frailty index, which was derived from comprehensive geriatric assessments of older adults within the UK Biobank and the TwinGene database (N = 175,226).

Results

Genetically predicted one standard deviation (SD) increase in own birth weight, but not offspring birth weight (maternal-specific), was linked to a decreased frailty index (β per SD increase = -0.068, 95%CI = -0.106 to -0.030, p = 3.92E-04). Conversely, genetically predicted one SD increase in childhood BMI was associated with an elevated frailty index (β per SD increase = 0.080, 95%CI = 0.046 to 0.114, p = 3.43E-06) with good statistical power (99.8%). The findings remained consistent across sensitivity analyses and showed no horizontal pleiotropy (p > 0.05).

Conclusion

This MR study provides evidence supporting a causal relationship between lower birth weight, higher childhood BMI, and an increased risk of frailty.

Frailty in Midlife as a Predictor of Changes in Body Composition from Midlife into Old Age: A Longitudinal Birth Cohort Study

INTRODUCTION

Few studies have investigated the association between frailty and subsequent body composition.

METHODS

We performed separate linear mixed model analyses to study the associations between changes in the participant frailty status assessed by a frailty index (FI) and subsequent body mass index (BMI), lean mass index (LMI), fat mass index (FMI), and FMI to LMI ratio values assessed on three occasions over 17 years. The analyses were carried out among 996 participants spanning from age 57 to 84 years.

RESULTS

With advancing age, LMI and BMI decreased, whereas FMI and FMI to LMI ratio increased. Participants with "stable frailty," followed by those with "increasing frailty" experienced faster decreases in LMI and faster increases in FMI and FMI to LMI ratio values from midlife into old age relative to those in the group "stable not frail." Contrastingly, those in the highest third of absolute annual increase in FMI and FMI to LMI ratio became more frail faster from midlife into old age relative to those in the lowest third.

CONCLUSIONS

We found evidence of an adverse health outcome of frailty where lean indices declined faster and fat indices and fat-to-lean ratios increased faster from midlife into old age. The changes resembled those that occurred with aging, but at a faster pace. The relationship between body composition and frailty is likely bidirectional, where high or increasing levels of fat are associated with the risk of becoming more frail earlier, but where a longer duration of frailty may increase the risk of faster age-related changes to body composition.

The brain insulin receptor gene network and associations with frailty index

OBJECTIVE

To investigate longitudinal associations between variations in the co-expression-based brain insulin receptor polygenic risk score and frailty, as well as change in frailty across follow-up.

METHODS

This longitudinal study included 1605 participants from the Helsinki Birth Cohort Study. Biologically informed expression-based polygenic risk scores for the insulin receptor gene network, which measure genetic variation in the function of the insulin receptor, were calculated for the hippocampal (hePRS-IR) and the mesocorticolimbic (mePRS-IR) regions. Frailty was assessed in at baseline in 2001-2004, 2011-2013 and 2017-2018 by applying a deficit accumulation-based frailty index. Analyses were carried out by applying linear mixed models and logistical regression models adjusted for adult socioeconomic status, birthweight, smoking and their interactions with age.

RESULTS

The FI levels of women were 1.19%-points (95% CI 0.12-2.26, P = 0.029) higher than in men. Both categorical and continuous hePRS-IR in women were associated with higher FI levels than in men at baseline (P < 0.05). In women with high hePRS-IR, the rate of change was steeper with increasing age compared to those with low or moderate hePRS-IR (P < 0.05). No associations were detected between mePRS-IR and frailty at baseline, nor between mePRS-IR and the increase in mean FI levels per year in either sex (P > 0.43).

CONCLUSIONS

Higher variation in the function of the insulin receptor gene network in the hippocampus is associated with increasing frailty in women. This could potentially offer novel targets for future drug development aimed at frailty and ageing.

Lifestyle-related factors in late midlife as predictors of frailty from late midlife into old age: a longitudinal birth cohort study

BACKGROUND

Few studies have examined longitudinal changes in lifestyle-related factors and frailty.

METHODS

We examined the association between individual lifestyle factors (exercise, diet, sleep, alcohol, smoking and body composition), their sum at baseline, their change over the 17-year follow-up and the rate of change in frailty index values using linear mixed models in a cohort of 2,000 participants aged 57-69 years at baseline.

RESULTS

A higher number of healthy lifestyle-related factors at baseline was associated with lower levels of frailty but not with its rate of change from late midlife into old age. Participants who stopped exercising regularly (adjusted β × Time = 0.19, 95%CI = 0.10, 0.27) and who began experiencing sleeping difficulties (adjusted β × Time = 0.20, 95%CI = 0.10, 0.31) experienced more rapid increases in frailty from late midlife into old age. Conversely, those whose sleep improved (adjusted β × Time = -0.10, 95%CI = -0.23, -0.01) showed a slower increase in frailty from late midlife onwards. Participants letting go of lifestyle-related factors (decline by 3+ factors vs. no change) became more frail faster from late midlife into old age (adjusted β × Time = 0.16, 95% CI = 0.01, 0.30).

CONCLUSIONS

Lifestyle-related differences in frailty were already evident in late midlife and persisted into old age. Adopting one new healthy lifestyle-related factor had a small impact on a slightly less steeply increasing level of frailty. Maintaining regular exercise and sleeping habits may help prevent more rapid increases in frailty.

Social Mobility and Health-Related Quality of Life Trajectory Classes Among Older Women and Men

OBJECTIVES

Changes in socioeconomic status (SES) during life may impact health in old age. We investigated whether social mobility and childhood and adulthood SES are associated with trajectories of health-related quality of life (HrQoL) over a 17-year period.

METHODS

We used data from the Helsinki Birth Cohort Study (n = 2003, 46% men, mean age 61.5 years). Social mobility was derived from childhood SES, obtained from healthcare records, and register-based adulthood SES.

RESULTS

Logistic regression models showed that lower adulthood SES was associated with lower physical HrQoL trajectories. Among men low (OR 3.95, p < .001), middle (OR 2.20, p = .006), and declining lifetime SES (OR 2.41, p = .001) were associated with lower physical HrQoL trajectories compared to men with high SES. Socioeconomic status was not associated with mental HrQoL trajectories.

DISCUSSION

Declining SES during life course may have negative health consequences, while improving SES is potentially as beneficial as high SES to later-life health among men.

Obesity, birth weight, and lifestyle factors for frailty: a Mendelian randomization study

Obesity, birth weight and lifestyle factors have been found associated with the risk of frailty in observational studies, but whether these associations are causal is uncertain. We conducted a two-sample Mendelian randomization study to investigate the associations. Genetic instruments associated with the exposures at the genome-wide significance level (p < 5 × 10-8) were selected from corresponding genome-wide association studies (n = 143,677 to 703,901 individuals). Summary-level data for the frailty index were obtained from the UK Biobank (n = 164,610) and Swedish TwinGene (n = 10,616). The β of the frailty index was 0.15 (p = 3.88 × 10-9) for 1 standard deviation increase in the prevalence of smoking initiation, 0.19 (p = 3.54 × 10-15) for leisure screen time, 0.13 (p = 5.26 × 10-7) for body mass index and 0.13 (p = 1.80 × 10-4) for waist circumference. There was a suggestive association between genetically predicted higher birth weight and moderate-to-vigorous intensity physical activity with the decreased risk of the frailty index. We observed no causal association between genetically predicted age of smoking initiation and alcoholic drinks per week with the frailty index. This study supports the causal roles of smoking initiation, leisure screen time, overall obesity, and abdominal obesity in frailty. The possible association between higher birth weight, proper physical activity and a decreased risk of frailty needs further confirmation.

Association between resilience and frailty in older age: Findings from the Helsinki Birth Cohort Study

OBJECTIVES

Resilience, a capacity to cope with adversity, has been linked to better functioning and health in older age. However, little is still known about resilience in relation to frailty. We explored whether resilience would be associated with frailty in older age and if we would observe differences in association between resilience and frailty according to the type of adversity.

METHODS

The study included 681 participants from the Helsinki Birth Cohort Study, born in Helsinki between 1934 and 1944. Adversities in older age and resilience were assessed between 2015 and 2018 with the Hardy-Gill resilience scale, scores ranging from 0 (low) to 18 (high resilience). Frailty was assessed in 2017-18 by using a deficit accumulation-based Frailty Index with a scale from 0 to 1. Adversities were coded into categories by using a data-driven approach. A linear regression analysis was used to explore the association between resilience and frailty.

RESULTS

Resilience was inversely associated with frailty in older age (β -0.009, 95% CI -0.011 to -0.007, p<0.001). The association was observed for all other type of adversities except adversity in relationships and economical adversity.

DISCUSSION

A higher resilience was related to lower levels of frailty in older age. Differences in association between resilience and frailty were observed according to the type of adversity. Focusing on the type of adverse events and the capacity to "bounce back" after an adversity in older age may reveal new perspectives on how to prevent and postpone frailty.

Frailty in Late Midlife to Old Age and Its Relationship to Medical Imaging Use and Imaging-related Costs: A Longitudinal Study

Background Frailty, defined as an increased vulnerability to and impaired recovery from stressors, is common in individuals in late midlife to old age. While frailty predisposes individuals to adverse health outcomes and increased health care utilization, how it impacts imaging service use and related costs remains unclear. Purpose To determine whether frailty is associated with greater use of imaging services and higher imaging-related costs. Materials and Methods This longitudinal study included a subset of participants from the Helsinki Birth Cohort Study who were clinically assessed up to three times from late midlife to old age between August 2001 and September 2018. A frailty index (FI) based on 41 variables was calculated, and an FI of 0.25 or more indicated frailty. Associations of baseline frailty and its rate of change during the study with medical imaging service use and imaging-related costs were assessed using covariate-adjusted negative binomial and other generalized linear models. Results Of the 1995 participants (mean age, 61.5 years ± 2.9 [SD]; 1074 female participants) included in this study, 569 (28.5%) were identified as frail at baseline, and these participants underwent 10 677 (42.4%) of the 25 172 medical imaging examinations among the participants. Compared to participants who were not frail at baseline, participants who were frail at baseline showed increased use of all imaging modalities (incidence rate ratio [IRR], 2.28 [95% CI: 1.97, 2.64]; P < .001) and higher imaging costs (log annual cost, 3.26 [95% CI: 2.36, 4.50]; P < .001). Compared to participants with stable or slow change in frailty (<0.0010 FI units per year), participants with a rapid increase in frailty (>0.0064 FI units per year) from late midlife to old age showed greater use of all medical imaging services, independent of FI at baseline (IRR, 1.82 [95% CI: 1.53, 2.17]; P < .001) and had higher imaging costs (log annual cost, 1.62 [95% CI: 1.30, 2.01)]; P < .001). Conclusion The presence of frailty and its progression rate are associated with increased use of imaging services and higher imaging-related costs. © RSNA, 2023 Supplemental material is available for this article.

Body Composition in Late Midlife as a Predictor of Accelerated Age-associated Deficit-accumulation From Late Midlife into Old Age: A Longitudinal Birth Cohort Study

BACKGROUND

Body mass index (BMI) may not be an optimal predictor of frailty as its constituents, lean and fat mass, may have opposite associations with frailty.

METHODS

A linear mixed model analysis was performed in the Helsinki Birth Cohort Study (n = 2 000) spanning from 57 to 84 years. A 39-item frailty index (FI) was calculated on three occasions over 17 years. Body composition in late midlife included BMI, percent body fat (%BF), waist-to-hip ratio (WHR), lean mass index (LMI), and fat mass index (FMI).

RESULTS

Mean FI levels increased by 0.28%/year among men and by 0.34%/year among women. Among women, per each kg/m2 higher BMI and each unit higher %BF the increases in FI levels per year were 0.013 percentage points (PP) steeper (95% CI = 0.004, 0.023) and 0.009 PP steeper (95% CI = 0.002, 0.016) from late midlife into old age. Among men, per each 0.1-unit greater WHR the increase in FI levels was 0.074 PP steeper per year (95% CI = -0.0004, 0.148). Cross-sectionally, greater FMI and LMI in late midlife were associated with higher FI levels but the direction of the association regarding LMI changed after adjustment for FMI. The categories "high FMI and high LMI" and "high FMI and low LMI" showed the highest FI levels relative to the category "low FMI and low LMI".

CONCLUSIONS

In late midlife, greater adiposity (%BF) among women and abdominal obesity (WHR) among men may predispose to higher levels of frailty from late midlife into old age. Greater lean mass alone may be protective of frailty, but not in the presence of high fat mass.