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• Leveraging large biobank studies to develop intrinsic capacity scores is essential and feasible. • Factor analysis confirmed intrinsic capacity as one general factor and five specific factors. • Better goodness of fit was observed with the bifactor model versus conventional structure. • The intrinsic capacity score from the bifactor model has good construct and predictive validity. • The intrinsic capacity score can be used as a single reliable measure of intrinsic capacity. In 2015, the World Health Organization introduced the concept of intrinsic capacity (IC) to define the individual-level characteristics that enable an older person to be and do the things they value. This study developed an intrinsic capacity score for UK Biobank study participants and validated its use as a tool for health outcome prediction, understanding healthy aging trajectories, and genetic research. Our analysis included data from 45,208 UK biobank participants who had a complete record of the ten variables included in the analysis. Factor adequacy was tested using Kaiser–Meyer–Olkin, Barthelt's, and the determinant of matrix tests, and the number of factors was determined by the parallel analysis method. Exploratory and confirmatory factor analyses were employed to determine the structure and dimensionality of indicators. Finally, the intrinsic capacity score was generated, and its construct and predictive validities as well as reliability were assessed. The factor analysis identified a multidimensional construct comprising one general factor (intrinsic capacity) and five specific factors (locomotor, vitality, cognitive, psychological, and sensory). The bifactor structure showed a better fit (comparative fit index = 0.995, Tucker Lewis index = 0.976, root mean square error of approximation = 0.025, root mean square residual = 0.009) than the conventional five-factor structure. The intrinsic capacity score generated using the bifactor confirmatory factor analysis has good construct validity, as demonstrated by an inverse association with age (lower intrinsic capacity in older age; (β) =−0.035 (95%CI: −0.036, −0.034)), frailty (lower intrinsic capacity score in prefrail participants, β = −0.104 (95%CI: (−0.114, −0.094)) and frail participants, β = −0.227 (95%CI: −0.267, −0.186) than robust participants), and comorbidity (a lower intrinsic capacity score associated with increased Charlson's comorbidity index, β =−0.019 (95%CI: −0.022, −0.015)). The intrinsic capacity score also predicted comorbidity (a one-unit increase in baseline intrinsic capacity score led to a lower Charlson's comorbidity index, β = 0.147 (95%CI: −0.173, −0.121)) and mortality (a one-unit increase in baseline intrinsic capacity score led to 25 % lower risk of death, odds ratio = 0.75(95%CI: 0.663, 0.848)). The bifactor structure showed a better fit in all goodness of fit tests. The intrinsic capacity construct has strong structural, construct, and predictive validities and is a promising tool for monitoring aging trajectories. [ABSTRACT FROM AUTHOR]

Background: Multimorbidity has been shown in several studies to relate to impaired physical function in later life. Aims: To examine if self-report of multimorbidity predicts impaired physical functioning, as assessed by formal physical function testing, in community-dwelling older adults. Methods: Non-communicable diseases (NCDs) were self-reported by 443 older community-dwelling UK adults via questionnaire, asking the question: 'Have you been told by a doctor that you have any of the following conditions?' Assessments of walking speed, chair stands and balance allowed us to create a composite score (0–12) on which impaired physical functioning was defined as ≤ 9. Results: The mean age of participants was 75.5 ± 2.5 years for men and 75.8 ± 2.6 for women. The proportion of individuals with impaired physical functioning was 71.2% in women and 56.9% in men. Having four or more NCDs was associated with an increased risk of poor physical function in men and women (p < 0.05). The number of medications and medicated systems was associated with gait speed (p < 0.03 and < 0.02, respectively) and timed up-and-go tests (p < 0.03 and < 0.02, respectively) in women but not men. Discussion and conclusion: Self-report of 4 or more NCDs was associated with an increased risk of poor physical function, an outcome which has previously been associated with adverse clinical sequelae. This observation may inform development of a simple screening tool to look for poor physical function in older adults. [ABSTRACT FROM AUTHOR]

Background: Despite compelling evidence from the United States of ethnic inequalities in physical functioning and ethnic differences in risk factors for poor physical functioning, very little is known about ethnic differences in the United Kingdom. Furthermore, the life stage at which these ethnic differentials are first observed has not been examined.Methods: Using cross-sectional data from Wave 1 of the UK Household Longitudinal Study (UKHLS), we compared self-reported physical functioning among 35,816 White British, 4,450 South Asian and 2,512 African Caribbean men and women across different stages of adulthood (young adulthood, early middle age, late middle age, older age). Regression analyses examined ethnic differences in functional limitations, with adjustment for socioeconomic and clinical covariates. Ethnicity by sex and ethnicity by age-group interactions were examined, and subgroup heterogeneity was explored.Results: Compared with White British adults over the age of 60, older South Asian men and women reported higher odds of functional limitations (odds ratio [OR] 2.77 [95% confidence interval {CI}: 2.00-3.89] and OR 3.99 [2.61-6.10], respectively); these ethnic differentials were observed as early as young adulthood. Young African Caribbean men had lower odds of functional limitations than White British men (OR 0.56 [0.34-0.94]), yet African Caribbean women reported higher odds of functional limitations in older age (OR 1.84 [1.21-2.79]).Conclusions: There is an elevated risk of functional limitations relating to ethnicity, even in young adulthood where the impact on future health and socioeconomic position is considerable. When planning and delivering health care services to reduce ethnic inequalities in functional health, the intersectionality with age and sex should be considered. [ABSTRACT FROM AUTHOR]

The 'inequality hypothesis' proposes that higher levels of societal income inequality have a direct negative causal effect on health. Support for this hypothesis has been mixed; particularly among older people. However, most previous studies have not accounted for people's exposure to inequality over the long-term. We aimed to address this problem by examining the implications of long-term inequality exposure for older people's physical health. Data on individual health and covariates were drawn from three large, comparable surveys of older people, covering 16 countries: the English Longitudinal Study of Ageing, the Survey of Health and Retirement in Europe and the U.S. Health and Retirement Study. Historical inequality information was derived from the Standardised World Income Inequality Database. We used multilevel regression methods to model the association between long-term average inequality and three measures of physical functioning: grip strength, lung function and self-reported activity limitation. Exposure to higher average long-term levels of inequality was significantly negatively related to objectively measured grip strength and lung function, but unrelated to self-reported limitations (although increasing inequality over time was positively related to self-reported limitations). The grip strength and lung function associations were partially explained by between-country differences in height, and in the latter case this factor may fully account for the apparent effect of inequality. We discuss implications of these results for the inequality hypothesis. [ABSTRACT FROM AUTHOR]

Background: To further increase our understanding of socio-economic health inequalities, we need studies considering multiple socio-economic circumstances and comparing different cultural contexts. This study compared the associations of past and present socio-economic circumstances with physical functioning between employees from Finland and Britain. Methods: Cross-sectional survey data from the Helsinki Health Study (n=5866) and the Whitehall II Study (n=3052) were used. Participants were white-collar public sector employees aged 45-60 years. Physical functioning was measured with the SF-36 physical component summary. The socio-economic indicators were parental and own education, childhood and current economic difficulties, occupational class, income, housing tenure. Results: Childhood and current economic difficulties were independently associated with physical functioning in both cohorts, although in London women childhood difficulties did not reach statistical significance. Own education was independently associated with physical functioning in Helsinki. Occupational class showed associations with physical functioning in both cohorts. These were mainly attenuated by education and income, but in London women there was a strong independent association. The association of income with physical functioning was attenuated by education (Helsinki) and occupational class (London). Parental education and housing tenure showed no consistent associations. Conclusions: Past and present economic difficulties were independently associated with physical functioning. The conventional socio-economic indicators showed less consistent associations which were partly mediated through other indicators and modified by the national context. The associations that varied according to the indicators and between the cohorts highlight the importance of considering the multiplicity of socio-economic circumstances and comparing different cultural contexts in further studies. [ABSTRACT FROM AUTHOR]

The article presents an observational cohort study which examines the prognosis of fatigue and functioning in primary care in Great Britain. Researchers collected measures of fatigue, perceived health and functioning, absenteeism, psychological symptoms and sleep from various published studies. According to the study, the severity of fatigue has a longitudinal relationship to poor sleep and psychosocial problems of patients.

Objective: to investigate the apparently incongruous coupling of poor physical functioning with high QoL. Study design and setting: face-to-face interview survey of random sample of 999 people aged 65+ across Britain. Results: twenty-one per cent of respondents reported fairly to very severe levels of functional difficulty, and 62% of these rated their QoL as 'good'. Better self-rated health, lower burden of chronic disease, not having fallen, higher social engagement and higher levels of perceived control over life, distinguished between people who had difficulties with physical functioning and who perceived their QoL to be 'good', rather than 'not good'. The open-ended survey responses broadly supported the quantitative findings. Conclusion: people with difficulties with physical functioning, who perceived their QoL to be 'not good', as opposed to 'good', were adversely affected by a higher burden of disease and having fewer socio-psychological resources to help them to cope effectively. [ABSTRACT FROM AUTHOR]

Background: there is increasing interest in how to age 'successfully' and in reaching consensus over its definition. Objective: to assess different models of successful ageing, using a British longitudinal survey of ageing in 2000-1. Setting: community, settings in Britain. Methods: five models of successful ageing were tested on a British cross-sectional population survey of 999 people aged 65+. The models were biomedical, broader biomedical, social, psychological and lay based. Results: the lay model emerged as the strongest. Respondents who were classified as successfully aged with this model, compared with those not successfully aged, had over five times the odds of rating their quality of life (QoL) as good rather than not good [odds ratio (OR) = 5.493, 95% confidence interval (95% CI) - 2.655-11.364]. Conclusion: the lay-based, more multidimensional, model of successful ageing predicted perceived QoL more powerfully than unidimensional models and should be used to evaluate the outcomes of health promotion in older populations. [ABSTRACT FROM AUTHOR]

Background: Associations between obesity and physical inactivity are bi-directional. Both are associated with physical functioning (PF, ability to perform physical tasks of daily living) but whether obesity influences PF via inactivity is unknown. We investigated whether mid-adult obesity trajectories were associated with subsequent PF and mediated by inactivity., Methods: Body mass index (BMI; kg/m²) and inactivity were recorded at: 36, 43, 53 and 60-64 years in the 1946 Medical Research Council (MRC) National Survey of Health and Development (1946-NSHD; n = 2427), and at 33, 42 and 50 years in the 1958 National Child Development Study (1958-NCDS; n = 8674). Poor PF was defined as the lowest (gender and cohort-specific) 10% on the Short-form 36 Physical Component Summary subscale at 60-64 years (1946-NSHD) and 50 years (1958-NCDS). Estimated randomized-interventional-analogue natural direct (rNDE) and indirect (rNIE) effects of obesity trajectories on PF via inactivity are expressed as risk ratios [overall total effect (rTE) is rNDE multiplied by rNIE]., Results: In both cohorts, most individuals (∼68%) were never obese in adulthood, 16-30% became obese and ≤11% were always obese. In 1946-NSHD, rTE of incident obesity at 43 years (vs never) on poor PF was 2.32 (1.13, 3.51); at 53 years it was 1.53 (0.91, 2.15). rNIEs via inactivity were 1.02 (0.97, 1.07) and 1.02 (0.99, 1.04), respectively. Estimated rTE of persistent obesity from 36 years was 2.91 (1.14, 4.69), with rNIE of 1.03 (0.96, 1.10). In 1958-NCDS, patterns of association were similar, albeit weaker., Conclusions: Longer duration of obesity was associated with increased risk of poor PF. Inactivity played a small mediating role. Findings reinforce the importance of preventing and delaying obesity onset to protect against poor PF., (© The Author(s) 2020. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Background: Evidence is scant on long-term implications of childhood obesity and body mass index (BMI) gains over the life-course for poor physical functioning (PF). The objective was to establish whether (i) birthweight and BMI across the life-course, (ii) BMI gains at specific life-stages and (iii) age of obesity onset were associated with PF at 50 y., Methods: In the 1958 British birth cohort (n = 8674), BMI (kg/m2) was calculated using height and weight [measured (7, 11, 16, 33 and 45 y); self-reported (23 and 50 y)]. PF was assessed at 50 y using the validated PF subscale of the Short-form 36 survey; the bottom (gender-specific) 10% was classified as poor PF. Missing data were imputed via multiple imputation. Associations were examined using logistic regression, adjusting for health and social factors., Results: Birthweight was not associated with PF. At each adult age, odds of poor PF were highest for obese (vs normal), e.g. for 23 y obesity the odds ratio (OR)adjusted for poor PF was 2.28 (1.34, 3.91) and 2.67 (1.72, 4.14) in males and females respectively. BMI gains were associated with poor PF, e.g. for females, ORadjusted per standard deviation (SD) in BMI gain 16-23 y was 1.28 (1.13, 1.46); for BMI gains 45-50 y it was 1.36 (1.11, 1.65). Longer duration of obesity was associated with poor PF, e.g. in males, ORadjusted was 2.32 (1.26, 4.29) for childhood obesity onset and 1.50 (1.16, 1.96) for mid-adulthood onset (vs never obese, P-trend < 0.001)., Conclusion: Obesity, BMI gains, and earlier obesity onset were associated with poor PF in mid-adulthood, reinforcing the importance of preventing and delaying obesity onset., (© The Author(s) 2019; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.)