Relationships Between Level and Change in Sarcopenia and Other Body Composition Components and Adverse Health Outcomes: Findings from the Health, Aging, and Body Composition Study.

We investigated how baseline values and rates of decline in components of sarcopenia and other body composition parameters relate to adverse clinical outcomes using the Health, Aging, and Body Composition Study. 2689 participants aged 70-79 years were studied. Appendicular lean mass, whole body fat mass, and total hip BMD were ascertained using DXA; muscle strength by grip dynamometry; and muscle function by gait speed. Baseline values and 2-3 year conditional changes (independent of baseline) in each characteristic were examined as predictors of mortality, hospital admission, low trauma fracture, and recurrent falls in the subsequent 10-14 years using Cox regression (generalized estimating equations used for recurrent falls) with adjustment for sex, ethnicity, age, and potential confounders. Lower levels and greater declines in all parameters (excluding hip BMD level) were associated (p < 0.05) with increased rates of mortality; fully-adjusted hazard ratios per SD lower gait speed and grip strength were 1.27 (95% CI 1.19, 1.36) and 1.14 (1.07, 1.21), respectively. Risk factors of hospital admission included lower levels and greater declines in gait speed and grip strength, and greater declines in hip BMD. Lower levels and greater declines in fat mass and hip BMD were associated with low trauma fracture. Lower gait speed, higher fat mass, and both lower levels and greater declines in grip strength were related to recurrent falls. Lower baseline levels and greater declines in musculoskeletal parameters were related to adverse outcomes. Interventions to maximize peak levels in earlier life and reduce rates of age-related decline may reduce the burden of disease in this age group.

Long-term rates of change in musculoskeletal aging and body composition: findings from the Health, Aging and Body Composition Study.

Musculoskeletal disorders are common among older people. Preventive strategies require understanding of age-related changes in strength, function and body composition, including how they interrelate. We have described, and examined associations between, 9-year changes in these parameters among 2917 Health, Aging and Body Composition Study participants (aged 70-79 years). Appendicular lean mass (ALM), whole body fat mass and total hip BMD were ascertained using DXA; muscle strength by grip dynamometry; and muscle function by gait speed. For each characteristic annualised percentage changes were calculated; measures of conditional change (independent of baseline) were derived and their interrelationships were examined using Pearson correlations; proportion of variance at 9-year follow-up explained by baseline level was estimated; and mean trajectories in relation to age were estimated using linear mixed models. Analyses were stratified by sex. Median [lower quartile, upper quartile] annual percentage declines were grip strength (1.5 [0.0, 2.9]), gait speed (2.0 [0.6, 3.7]), ALM (0.7 [0.1, 1.4]), fat mass (0.4 [- 1.1, 1.9]) and hip BMD (0.5 [0.0, 1.1]). Declines were linear for ALM and accelerated over time for other characteristics. Most conditional change measures were positively correlated, most strongly between ALM, fat mass and hip BMD (r > 0.28). Proportion of variation at follow-up explained by baseline was lower for grip strength and gait speed (39-52%) than other characteristics (69-86%). Strength and function declined more rapidly, and were less correlated between baseline and follow-up, than measures of body composition. Therefore, broader intervention strategies to prevent loss of strength and function in later life are required as those targeting body composition alone may be insufficient.

Intergenerational effect of early-life growth on offspring height: Evidence from the Hertfordshire Cohort Study.

BACKGROUND: Previous intergenerational (parent to child) and transgenerational (grandparent to grandchild) studies have shown there is a link between parental and offspring birthweight. OBJECTIVES: The aim was to explore the association between the early-life weight gain of an individual and the adult height of their children and grandchildren. METHODS: Study participants across three generations of the Hertfordshire Cohort Study (HCS) were included in this study. Health visitors recorded the birthweight (kg) and weight at 1 year (kg) of the original (F0 generation) HCS participants when they were born in Hertfordshire between 1931 and 1939. A conditional infant weight gain score for F0 participants was calculated using birthweight and weight at 1 year, and self-reported height (cm) of their children (F1 generation) and their grandchildren (F2 generation) was obtained from postal questionnaires. Due to the lack of clustering within family lines, linear regression analysis was used to compare intergenerational relationships. RESULTS: Data were available from 139 F0, 148 F1, and 198 F2 participants. A positive association was found between parental birthweight (F0) and offspring adult height; on average, a 1 kg increase in F0 birthweight was associated with a 2.04 cm increase in F1 adult height (beta 2.04, 95% confidence interval [CI] -0.03, 4.10). A positive association was found between F0 conditional weight gain during the first year of life and offspring (beta 1.53, 95% CI 0.45, 2.62) and grandchild height (beta 1.06, 95% CI 0.03, 2.10). Positive associations were also found between F0 weight at 1 year and offspring (beta 1.83, 95% CI 0.79, 2.87) and grandchild height (beta 0.91, 95% CI -0.10, 1.91). CONCLUSION: This study demonstrates an association between grandparental weight gain in early life and the heights of their children and grandchildren. The results of these analyses highlight the importance of early-life weight gain on the adult stature of subsequent offspring.

Relationships between informal caregiving, health and work in the Health and Employment After Fifty study, England.

BACKGROUND: To investigate the prevalence of caregiving and its relationship with work, health and socio-economic circumstances in the Health and Employment After Fifty (HEAF) study. METHODS: The HEAF study comprises 8134 men and women aged 50-64 years recruited from 24 general practices. Socio-demographic, lifestyle and health characteristics and hours per week giving personal care were elicited by postal questionnaire. Objective clinical information about diagnoses/medications was retrieved from health records. Work-related and health risk factors for intense caring responsibilities (≥20 h/week vs. no hours) were explored using logistic regression with adjustment for age and social class. RESULTS: In all, 644 (17%) men and 1153 (26%) women reported caring responsibilities, of whom 93 and 199 were intense caregivers, who were more likely to be socio-economically disadvantaged; less likely to be working and, if combining caring with working (41 men and 90 women), more likely to be part-time/working shifts, than non-carers. Men caring ≥20 h/week were more likely to have COPD and to report musculoskeletal pain, poor/fair self-rated health, depression and sleep problems. Among working women, caring ≥20 h/week was associated with these same health outcomes and also with a doctor-diagnosed mental health problem or musculoskeletal pain in the previous year. CONCLUSIONS: Caregiving is common and unequal in the HEAF cohort, with more high-intensity informal care provided by those with greater levels of socio-economic deprivation, which could affect their employment and health. Caregivers need support to lead long, healthy lives, rather than becoming care needers themselves. Employers and governments need to take caregiving into account and support it actively.

Health Care Costs Associated With Muscle Weakness: A UK Population-Based Estimate.

Sarcopenia and muscle weakness are responsible for considerable health care expenditure but little is known about these costs in the UK. To address this, we estimated the excess economic burden for individuals with muscle weakness regarding the provision of health and social care among 442 men and women (aged 71-80 years) who participated in the Hertfordshire Cohort Study (UK). Muscle weakness, characterised by low grip strength, was defined according to the Foundation for the National Institutes of Health criteria (men < 26 kg, women < 16 kg). Costs associated with primary care consultations and visits, outpatient and inpatient secondary care, medications, and formal (paid) as well as informal care for each participant were calculated. Mean total costs per person and their corresponding components were compared between groups with and without muscle weakness. Prevalence of muscle weakness in the sample was 11%. Mean total annual costs for participants with muscle weakness were £4592 (CI £2962-£6221), with informal care, inpatient secondary care and primary care accounting for the majority of total costs (38%, 23% and 19%, respectively). For participants without muscle weakness, total annual costs were £1885 (CI £1542-£2228) and their three highest cost categories were informal care (26%), primary care (23%) and formal care (20%). Total excess costs associated with muscle weakness were £2707 per person per year, with informal care costs accounting for 46% of this difference. This results in an estimated annual excess cost in the UK of £2.5 billion.

Associations Between Objectively Measured Physical Activity, Body Composition and Sarcopenia: Findings from the Hertfordshire Sarcopenia Study (HSS).

Regular physical activity (PA) is associated with reduced risk of the development and progression of musculoskeletal, metabolic and vascular disease. However, PA declines with age and this can contribute to multiple adverse outcomes. The aims of this study were to describe the relationship between accelerometer-determined PA, body composition and sarcopenia (the loss of muscle mass and function with age). Seven-day PA was measured using the GENEactiv accelerometer among 32 men and 99 women aged 74-84 years who participated in the Hertfordshire Sarcopenia Study. We measured mean daily acceleration and minutes/day spent in non-sedentary and moderate-to-vigorous physical activity (MVPA) levels. Body composition was measured by dual-energy X-ray absorptiometry, muscle strength by grip dynamometry and function by gait speed. Sarcopenia was defined according to the EWGSOP diagnostic algorithm. Men and women spent a median (inter-quartile range) of 138.8 (82, 217) and 186 (122, 240) minutes/day engaging in non-sedentary activity but only 14.3 (1.8, 30.2) and 9.5 (2.1, 18.6) min in MVPA, respectively. Higher levels of PA were associated with reduced adiposity, faster walking speed and decreased risk of sarcopenia. For example, a standard deviation (SD) increase in mean daily acceleration was associated with an increase in walking speed of 0.25 (95% CI 0.05, 0.45) SDs and a reduction in the risk of sarcopenia of 35% (95% CI 1, 57%) in fully adjusted analyses. PA was not associated with hand grip strength. Community-dwelling older adults in this study were largely sedentary but there was evidence that higher levels of activity were associated with reduced adiposity and improved function. PA at all intensity levels in later life may help maintain physical function and protect against sarcopenia.

Influences on diet quality in older age: the importance of social factors.

Background: poor diet quality is common among older people, but little is known about influences on food choice, including the role of psychosocial factors at this age. Objective: to identify psychosocial correlates of diet quality in a community-dwelling population of men and women aged 59-73 years; to describe relationships with change in diet quality over 10 years. Design: Longitudinal cohort, Hertfordshire Cohort Study (HCS). Subjects: HCS participants assessed at baseline (1998-2003: 1,048 men, 862 women); 183 men and 189 women re-assessed in 2011. Methods: diet was assessed by administered food frequency questionnaire; diet scores were calculated to describe diet quality at baseline and follow-up. A range of psychosocial factors (social support, social network, participation in leisure activities, depression and anxiety, sense of control) were assessed by questionnaire. Results: at baseline, better diet quality was related to a range of social factors, including increased confiding/emotional social support (men and women), practical support (men) and a larger social network (women) (all P < 0.05). For both men and women, greater participation in social and cognitive leisure activities was related to better diet quality (P < 0.005). There were few associations between measured psychosocial factors at baseline and change in diet score over 10 years, in the follow-up sub-group. However, greater participation in leisure activities, especially cognitive activities, at baseline was associated with smaller declines in diet quality over the 10-year follow-up period for both men (P = 0.017) and women (P = 0.014). Conclusions: in community-dwelling older adults, a range of social factors, that includes greater participation in leisure activities, were associated with diets of better quality.

Identification of risk factors for hospital admission using multiple-failure survival models: a toolkit for researchers.

BACKGROUND: The UK population is ageing; improved understanding of risk factors for hospital admission is required. Linkage of the Hertfordshire Cohort Study (HCS) with Hospital Episode Statistics (HES) data has created a multiple-failure survival dataset detailing the characteristics of 2,997 individuals at baseline (1998-2004, average age 66 years) and their hospital admissions (regarded as 'failure events') over a 10 year follow-up. Analysis of risk factors using logistic regression or time to first event Cox modelling wastes information as an individual's admissions after their first are disregarded. Sophisticated analysis techniques are established to examine risk factors for admission in such datasets but are not commonly implemented. METHODS: We review analysis techniques for multiple-failure survival datasets (logistic regression; time to first event Cox modelling; and the Andersen and Gill [AG] and Prentice, Williams and Peterson Total Time [PWP-TT] multiple-failure models), outline their implementation in Stata, and compare their results in an analysis of housing tenure (a marker of socioeconomic position) as a risk factor for different types of hospital admission (any; emergency; elective; >7 days). The AG and PWP-TT models include full admissions histories in the analysis of risk factors for admission and account for within-subject correlation of failure times. The PWP-TT model is also stratified on the number of previous failure events, allowing an individual's baseline risk of admission to increase with their number of previous admissions. RESULTS: All models yielded broadly similar results: not owner-occupying one's home was associated with increased risk of hospital admission. Estimated effect sizes were smaller from the PWP-TT model in comparison with other models owing to it having accounted for an increase in risk of admission with number of previous admissions. For example, hazard ratios [HR] from time to first event Cox models were 1.67(95 % CI: 1.36,2.04) and 1.63(95 % CI:1.36,1.95) for not owner-occupying one's home in relation to risk of emergency admission or death among women and men respectively; corresponding HRs from the PWP-TT model were 1.34(95 % CI:1.15,1.56) for women and 1.23(95 % CI:1.07,1.41) for men. CONCLUSION: The PWP-TT model may be implemented using routine statistical software and is recommended for the analysis of multiple-failure survival datasets which detail repeated hospital admissions among older people.

Global variation in grip strength: a systematic review and meta-analysis of normative data.

BACKGROUND: weak grip strength is a key component of sarcopenia and is associated with subsequent disability and mortality. We have recently established life course normative data for grip strength in Great Britain, but it is unclear whether the cut points we derived for weak grip strength are suitable for use in other settings. Our objective was to investigate differences in grip strength by world region using our data as a reference standard. METHODS: we searched MEDLINE and EMBASE for reporting age- and gender-stratified normative data for grip strength. We extracted each item of normative data and converted it on to a Z-score scale relative to our British centiles. We performed meta-regression to pool the Z-scores and compare them by world region. FINDINGS: our search returned 806 abstracts. Sixty papers met inclusion criteria and reported on 63 different samples. Seven UN regions were represented, although most samples (n = 44) were based in developed regions. We extracted 726 normative data items relating to 96,537 grip strength observations. Normative data from developed regions were broadly similar to our British centiles, with a pooled Z-score 0.12 SDs (95% CI: 0.07, 0.17) above the corresponding British centiles. By comparison, normative data from developing regions were clearly lower, with a pooled Z-score of -0.85 SDs (95% CI: -0.94, -0.76). INTERPRETATION: our findings support the use of our British grip strength centiles and their associated cut points in consensus definitions for sarcopenia and frailty across developed regions, but highlight the need for different cut points in developing regions.

Grip strength among community-dwelling older people predicts hospital admission during the following decade.

BACKGROUND: Lower grip strength on admission to hospital is known to be associated with longer stay, but the link between customary grip and risk of future admission is less clear. OBJECTIVE: To compare grip strength with subsequent risk of hospital admission among community-dwelling older people in a U.K. setting. DESIGN: Cohort study with linked administrative data. SETTING: Hertfordshire, U.K. SUBJECTS: A total of 2,997 community-dwelling men and women aged 59-73 years at baseline. METHODS: The Hertfordshire Cohort Study (HCS) participants completed a baseline assessment between 1998 and 2004, during which grip strength was measured. Hospital Episode Statistics and mortality data to March 2010 were linked with the HCS database. Statistical models were used to investigate the association of grip strength with subsequent elective, emergency and long-stay hospitalisation and readmission. RESULTS: There was a statistically significant negative association between grip strength and all classes of admission in women [unadjusted hazard ratio per standard deviation (SD) decrease in grip strength for: any admission/death 1.10 (95% CI: 1.06, 1.14), elective admission/death 1.09 (95% CI: 1.05, 1.13), emergency admission/death 1.21 (95% CI: 1.13, 1.31), long-stay admission/death 1.22 (95% CI: 1.13, 1.32) and unadjusted relative risk per SD decrease in grip strength for 30-day readmission/death 1.30 (95% CI: 1.19, 1.43)]. These associations remained significant after adjustment for potential confounding factors (age, height, weight for height, smoking, alcohol, social class). In men, unadjusted rates for emergency admission/death, long-stay admission/death and readmission/death were significantly associated with grip strength; associations that similarly withstood adjustment. CONCLUSION: This study provides the first evidence that grip strength among community-dwelling men and women in the U.K. is associated with risk of hospital admission over the following decade.

Processed meat consumption and lung function: modification by antioxidants and smoking.

Unhealthy dietary patterns are associated with poor lung function. It is not known whether this is due to low consumption of antioxidant-rich fruit and vegetables, or is a consequence of higher intakes of harmful dietary constituents, such as processed meat. We examined the individual and combined associations of processed meat, fruit and vegetable consumption and dietary total antioxidant capacity (TAC) with lung function among 1551 males and 1391 females in the UK in the Hertfordshire Cohort Study. Diet was assessed using a food frequency questionnaire. After controlling for confounders, processed meat consumption was negatively associated with forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio in males and females, while fruit and vegetable consumption and dietary TAC were positively associated with FEV1 and FVC, but not FEV1/FVC ratio. In males, the negative association between processed meat consumption and FEV1 was more marked in those who had low fruit and vegetable consumption (p=0.035 for interaction), and low dietary TAC (p=0.025 for interaction). The deficit in FEV1/FVC associated with processed meat consumption was larger in males who smoked (p=0.022 for interaction). Higher processed meat consumption is associated with poorer lung function, especially in males who have lower fruit and vegetable consumption or dietary TAC, and among current smokers.

Inflammation, telomere length, and grip strength: a 10-year longitudinal study.

Telomere attrition has been associated with age-related diseases, although causality is unclear and controversial; low-grade systemic inflammation (inflammaging) has also been implicated in age-related pathogenesis. Unpicking the relationship between aging, telomere length (TL), and inflammaging is hence essential to the understanding of aging and management of age-related diseases. This longitudinal study explored whether telomere attrition is a cause or consequence of aging and whether inflammaging explains some of the associations between TL and one marker of aging, grip strength. We studied 253 Hertfordshire Ageing Study participants at baseline and 10-year follow-up (mean age at baseline 67.1 years). Participants completed a health questionnaire and had blood samples collected for immune-endocrine and telomere analysis at both time points. Physical aging was characterized at follow-up using grip strength. Faster telomere attrition was associated with lower grip strength at follow-up (ß = 0.98, p = 0.035). This association was completely attenuated when adjusted for inflammaging burden (p = 0.86) over the same period. Similarly, greater inflammaging burden was associated with lower grip strength at follow-up (e.g., interleukin [IL]-1ß: ß = -2.18, p = 0.001). However, these associations were maintained when adjusted for telomere attrition (IL-1ß, p = 0.006). We present evidence that inflammaging may be driving telomere attrition and in part explains the associations that have previously been reported between TL and grip strength. Thus, biomarkers of physical aging, such as inflammaging, may require greater exploration. Further work is now indicated.

ACE inhibitors, statins and thiazides: no association with change in grip strength among community dwelling older men and women from the Hertfordshire Cohort Study.

BACKGROUND: vascular disease has been postulated to contribute to muscle dysfunction in old age. Previous studies examining the effects of cardiovascular drugs on muscle function have shown conflicting results. We therefore examined the association of angiotensin converting enzyme (ACE) inhibitor, thiazide and statin use with decline in grip strength in a well-characterised cohort. METHODS: we analysed prospectively collected data from the Hertfordshire Cohort Study (HCS). For each medication, participants were divided into no baseline use/no use at follow-up, baseline use/no use at follow-up, no baseline use but use at follow-up and use at baseline and follow-up. For each group, annualised decline in grip strength (kg per year) was calculated, then adjusted for baseline age, height, weight, baseline grip strength, indices of ischaemic heart disease and hypertension. Analyses were conducted separately for males and females. RESULTS: 639 participants were included in the analysis, mean age 65 years. 321 (50%) were male; mean follow-up time was 4.4 years. There were no differences in baseline grip between baseline users and non-users of any drug class. Adjusted grip strength change per year was similar for each group of ACE inhibitor use (P > 0.05). Similar analyses revealed no significant between-group differences for statin or thiazide use. Analysis of dropout rates by medication use revealed no evidence of selection bias. CONCLUSION: use of ACE inhibitors, statins or thiazides was not associated with differences in grip strength decline in healthy older people in the HCS.

Understanding NHS hospital admissions in England: linkage of Hospital Episode Statistics to the Hertfordshire Cohort Study.

BACKGROUND: concern over the sustainability of the National Health Service (NHS) is often focussed on rising numbers of hospital admissions, particularly among older people. Hospital admissions are enumerated routinely by the Hospital Episode Statistics (HES) Service, but published data do not allow individual-level service use to be explored. This study linked information on Hertfordshire Cohort Study (HCS) participants with HES inpatient data, with the objective of describing patterns and predictors of admissions among individuals. METHODS: 2,997 community-dwelling men and women aged 59-73 years completed a baseline HCS assessment between 1998 and 2004; HES and mortality data to 31 March 2010 were linked with the HCS database. This paper describes patterns of hospital use among the cohort at both the admission and individual person level. RESULTS: the cohort experienced 8,741 admissions; rates were 391 per 1,000 person-years among men (95% CI: 380, 402) and 327 among women (95% CI: 316, 338), P < 0.0001 for gender difference. A total of 1,187 men (75%) and 981 women (69%) were admitted to hospital at least once; among these, median numbers of admissions were 3 in men (inter-quartile range, (IQR): 1, 6) and 2 in women (IQR: 1, 5). Forty-eight percent of those ever admitted had experienced an emergency admission and 70% had been admitted overnight. DISCUSSION: It is possible to link routinely collected HES data with detailed information from a cohort study. Hospital admission is common among community-dwelling 'young-old' men and women. These linked datasets will facilitate research into lifecourse determinants of hospital admission and inform strategies to manage demand on the NHS.

Slow walking speed and health-related exit from employment among older workers over 5 years of follow-up: evidence from the Health and Employment After Fifty (HEAF) cohort study.

INTRODUCTION: With demographic changes, there is increasing demand for individuals and governments to lengthen working lives. Jobs that are very physically demanding are likely to be more difficult to sustain at older ages. If workers at risk of mismatch of demand and capability could be identified early, there would be opportunities for intervention for health or lifestyle and/or re-training or redeployment. OBJECTIVE: To investigate whether self-reported walking speed (a good measure of function in elderly people) predicted health-related job loss (HRJL) longitudinally over 5 years of follow-up among middle-aged workers. DESIGN: Data came from the Health and Employment After Fifty (HEAF) prospective cohort study of middle-aged people (aged 50-64 years) in UK. SETTING: General population survey (sampling frame was 24 General Practice registers). PARTICIPANTS: The cohort included 8134 people recruited in 2013-2014. For the current analyses, 5217 people who ever worked and completed at least one follow-up questionnaire were eligible. PRIMARY OUTCOME: Exit from employment mainly or partly for health reasons (HRJL). RESULTS: At baseline, very slow walking speed was associated with: obesity, physical inactivity, smoking (men), financial hardship, lower educational attainment and not being in professional occupations. In total, 527 people (10%) reported at least one HRJL during follow-up. After adjustment, the HR for HRJL among men with very slow walking-speed was 4.32, 95% CI 2.72 to 6.87 and among women was 4.47, 95% CI 3.04 to 6.57. After further adjustment for 'difficulty coping with physical demands at work', hazards remained doubled in men and women. CONCLUSIONS: Self-reported walking speed could help identify older workers who are at increased risk of HRJL. This could provide opportunities for intervention through optimising health and lifestyle, restricting physical workload, retraining or redeployment. Early appropriate intervention could enable longer working lives and promote healthier, more equal ageing.

Relationship of vitamin D status to adult lung function and COPD.

BACKGROUND: There is considerable interest in the possible role of vitamin D in respiratory disease, but only one population-based study has reported associations with lung function. METHODS: The cross-sectional relationships of total dietary vitamin D intake, serum 25 hydroxy vitamin D (25(OH)D) concentrations and three vitamin D receptor (VDR) polymorphisms (Apa1, Fok1 and Cdx2) with lung function and spirometrically-defined chronic obstructive pulmonary disease (COPD) were investigated in men and women aged 59-73 years in the Hertfordshire Cohort Study, UK. RESULTS: After controlling for confounders, total vitamin D intake was positively associated with forced expiratory volume in 1 s (FEV(1); difference in FEV(1) between top and bottom quintiles of intake 0.079 l (95% CI 0.02 to 0.14), p trend=0.007, n=2942), ratio of FEV(1) to forced vital capacity (FEV(1)/FVC; p trend=0.008) and negatively associated with COPD (OR comparing top and bottom quintiles 0.57 (95% CI 0.38 to 0.87), p trend=0.02). In contrast, serum 25(OH)D concentrations were not related to FEV(1) (p trend=0.89, n=1197) but were positively associated with COPD (p trend=0.046). VDR genotypes were unrelated to lung function and did not modify the effects of dietary intake or 25(OH)D concentrations on lung function. CONCLUSIONS: The results of this study did not confirm a positive association between blood 25(OH)D concentrations and adult lung function. The apparent relationships with dietary vitamin D are likely to be explained by other highly correlated nutrients in the diet.

Hertfordshire sarcopenia study: design and methods.

BACKGROUND: Sarcopenia is defined as the loss of muscle mass and strength with age. Although a number of adult influences are recognised, there remains considerable unexplained variation in muscle mass and strength between older individuals. This has focused attention on influences operating earlier in life. Our objective for this study was to identify life course influences on muscle mass and strength in an established birth cohort and develop methodology for collection of muscle tissue suitable to investigate underlying cellular and molecular mechanisms. METHODS: One hundred and five men from the Hertfordshire Cohort Study (HCS), born between 1931 and 1939 who have historical records of birth weight and weight at one year took part in the Hertfordshire Sarcopenia Study (HSS). Each participant consented for detailed characterisation of muscle mass, muscle function and aerobic capacity. In addition, a muscle biopsy of the vastus lateralis using a Weil-Blakesley conchotome was performed. Data on muscle mass, function and aerobic capacity was collected on all 105 participants. Muscle biopsy was successfully carried out in 102 participants with high rates of acceptability. No adverse incidents occurred during the study. DISCUSSION: The novel approach of combining epidemiological and basic science characterisation of muscle in a well established birth cohort will allow the investigation of cellular and molecular mechanisms underlying life course influences on sarcopenia.

Work participation and risk factors for health-related job loss among older workers in the Health and Employment after Fifty (HEAF) study: Evidence from a 2-year follow-up period.

INTRODUCTION: Rapidly increasing population old age dependency ratios create a growing economic imperative for people to work to older ages. However, rates of older worker employment are only increasing slowly. Amongst a cohort of contemporary older workers, we investigated risk factors for health-related job loss (HRJL) over 2 years of follow-up. METHODS: HEAF is a population based cohort study of adults in England (aged 50-64 years at baseline) who provided information about socio-demographic characteristics, lifestyle, and work at baseline and annual follow-ups. Exits from paid work were mapped and risk factors for HRJL explored in a multiple-record survival dataset by Cox proportional hazards models. RESULTS: 2475 (75%) men and 2668 (66%) women were employed; 115 (4.6%) men and 182 (6.8%) women reported HRJL. Employment as road transport drivers/in vehicle trades (men), or as teaching/education/nursing/midwifery professionals or in caring personal services (women), was more frequent among people exiting work for health-related versus non-health-related reasons. Principal socio-demographic and lifestyle risk factors for HRJL were: struggling financially (men and women); low physical activity (men); being overweight or obese, and current smoking (women). Mutually adjusted work-related risk factors for HRJL were job dissatisfaction, and not coping with the physical (hazard ratio [95% confidence interval]: men 5.34[3.40,8.39]; women 3.73[2.48,5.60]) or mental demands (women only, 2.02[1.38,2.96]) of work. CONCLUSIONS: Employment characteristics of contemporary older workers differ by sex. Job satisfaction and perceived ability to cope with the physical and mental demands of work are key determinants of HRJL which employers could potentially influence to enable work to older ages.

Body Mass Index (BMI) and Work Ability in Older Workers: Results from the Health and Employment after Fifty (HEAF) Prospective Cohort Study.

This study explores associations between BMI and prolonged sickness absence; cutting down at work; and health-related job loss (HRJL) over two years of follow-up among workers aged ≥50 years. A cohort of 2299 men and 2425 women (aged 50-64 years) self-reported height and weight at baseline and provided information about work ability at 12 and 24 months for the Health and Employment after Fifty (HEAF) Study. Associations between BMI and work ability were assessed by logistic regression and HRJL by multiple-record Cox's proportional hazards models, with adjustment for other risk factors. The prevalence of obesity/severe obesity was 22.6%/1.2% amongst men and 21.4%/2.6% amongst women, respectively. In men and women, obesity and severe obesity predicted having to cut down at work for health over two years. In women, severe obesity predicted prolonged sickness absence, and also HRJL even after adjustment for age, proximity to retirement, financial difficulties, and lifestyle factors (hazard ratio [HR] 2.93, 95% CI 1.38, 6.23), and additional adjustment for health conditions (HR 2.52, 95% CI 1.12, 5.67). Obesity, and particularly severe obesity, negatively impacts work ability amongst people aged 50-64 years, with greatest effects in women. Obesity can be expected to hinder attempts to encourage work to older ages.

The Hertfordshire Cohort Study: an overview.

The Hertfordshire Cohort Study is a nationally unique study of men and women born in the English county of Hertfordshire in the early part of the 20 th century. Records that detail their health in infancy and childhood have been preserved, their sociodemographic, lifestyle, medical and biological attributes have been characterised in later life, and routinely collected data on their hospital use and mortality have been acquired. This paper provides an overview of the study since its inception in the 1980s, including its methods, findings, and plans for its future.