A hypothesized benefit of social participation is that it encourages people to be more physically active. However, limited evidence exists on the association between social participation over the life-course and physical activity in midlife. We sought to apply a life-course framework to examine the association of social participation and device measured physical activity in midlife in the UK. We used the 1970 British Birth Cohort Study (BCS70), which includes all people born in Britain during a single week in 1970. Social participation was assessed at ages 16, 30, 34 and 42. Physical activity was measured by accelerometery at age 46, as mean daily step count and time spent in moderate to vigorous physical activity (MVPA). The associations of social participation and physical activity were tested using two different life-course models: the sensitive period model and the accumulation model. Individuals with medium and high participation compared to no social participation over their life-course had higher mean daily step count and MVPA in midlife, supporting the accumulation model. In the sensitive period model, only those that actively participated at age 42 had higher mean daily steps and MVPA compared to those who did not participate. Our study provides empirical evidence on the importance of sustaining social participation at all ages over the life-course rather than at a particular timepoint of someone\'s life. If our findings reflect causal effects, interventions to promote social participation throughout the life-course could be an avenue to promote physical activity in middle life.

BACKGROUND: Life course epidemiology examines associations between repeated measures of risk and health outcomes across different phases of life. Empirical research, however, is often based on discrete-time models that assume that sporadic measurement occasions fully capture underlying long-term continuous processes of risk.
METHODS: We propose (i) the functional relevant life course model (fRLM), which treats repeated, discrete measures of risk as unobserved continuous processes, and (ii) a testing procedure to assign probabilities that the data correspond to conceptual models of life course epidemiology (critical period, sensitive period and accumulation models). The performance of the fRLM is evaluated with simulations, and the approach is illustrated with empirical applications relating body mass index (BMI) to mRNA-seq signatures of chronic kidney disease, inflammation and breast cancer.
RESULTS: Simulations reveal that fRLM identifies the correct life course model with three to five repeated assessments of risk and 400 subjects. The empirical examples reveal that chronic kidney disease reflects a critical period process and inflammation and breast cancer likely reflect sensitive period mechanisms.
CONCLUSIONS: The proposed fRLM treats repeated measures of risk as continuous processes and, under realistic data scenarios, the method provides accurate probabilities that the data correspond to commonly studied models of life course epidemiology. fRLM is implemented with publicly-available software.

We expand on previous studies investigating the links between early health and later health by examining four distinct dimensions of early-life health and multiple life course outcomes, including the age of onset of serious cardiovascular diseases (CVDs) and several job-related health outcomes. The four dimensions of childhood health are mental, physical, self-reported general health, and severe headaches or migraines. The data set we use includes men and women in 21 countries from the Survey of Health, Ageing and Retirement in Europe. We find that the different dimensions of childhood health have unique ties to later outcomes. For men, early mental health problems play a stronger role for life course job-related health outcomes, but early poor/fair general health is more strongly linked to the spike in onset of CVDs in their late 40s. For women, these links between childhood health dimensions and life course outcomes are similar but are less clear-cut than for men. The spike in onset of CVDs in women\'s late 40s is driven by those with severe headaches or migraines, while those with early poor/fair general health or mental health problems do worse as captured by job-related outcomes. We also delve into and control for possible mediating factors. Exploring the links between several dimensions of childhood health and multiple health-related life course outcomes will enable a better understanding of how health inequalities originate and are shaped over the course of people\'s lives.

Cardiometabolic health in adulthood is associated with socioeconomic position (SEP) in childhood. Although this has been studied by previous research several questions need to be addressed. E.g. knowledge about the association with timing, extent of the exposure as well as lifestyle and adult SEP, is essential to address the increasing social gradient in cardiometabolic diseases.
This study included a sub-sample (N = 264, 50% women, age 28-30) from an ongoing cohort study. We used a combination of national registers, longitudinal questionnaire data and clinical data. We examined the association between childhood SEP and cardiometabolic risk, measured by a score of multiple risk markers in young adulthood. SEP-indicators included mother\'s educational level and household income. The association was evaluated by four different life course models; the latent effects model, the pathway model, the cumulative model and the social mobility model.
We found an inverse association between mother\'s educational level and cardiometabolic risk. The association was statistically significant evaluated by the pathway and cumulative life course models, however statistically insignificant evaluated by the latent effects model. No specific association with social mobility was observed. However, high adult educational level seems to have a protecting impact on the association. No association was found between household income and cardiometabolic risk in any of the applied life course models.
Low childhood SEP, represented by mother\'s educational level but not household income, is associated with increased cardiometabolic risk in young adulthood. The accumulation of exposure, lifestyle and adult educational attainment are important for the association. In contrast, intergenerational social mobility does not seem to have a specific impact on the association and we find no evidence for a particular timing in childhood.

The present study extends prior research on the links between social adversity and aging by employing more comprehensive measures of adversity and a new gene expression index of aging. Hierarchical regression and 20 years of data from a sample of 381 black Americans were used to test models regarding the impact of social adversity on speed of aging. Consistent with the early life sensitivity model, early adversity continued to predict accelerated aging after controlling for adult adversity. Contrary to the pathway model, adult adversity was not related to aging following controls for early adversity. The cumulative stress model received partial support as high adversity during adulthood amplified the effect of early adversity on aging. Finally, consonant with the social change model, low adversity during adulthood buffered the effect of early adversity on aging. These findings held after controlling for health behaviors such as smoking, diet, and exercise.

There is growing interest in understanding which aspects of the local environment influence obesity. Using data from the longitudinal West of Scotland Twenty-07 study (n = 2040) we examined associations between residents\' self-reported neighbourhood problems, measured over a 13-year period, and nurse-measured body weight and size (body mass index, waist circumference, waist⁻hip ratio) and percentage body fat. We also explored whether particular measures such as abdominal obesity, postulated as a marker for stress, were more strongly related to neighbourhood conditions. Using life course models adjusted for sex, cohort, household social class, and health behaviours, we found that the accumulation of perceived neighbourhood problems was associated with percentage body fat. In cross-sectional analyses, the strongest relationships were found for contemporaneous measures of neighbourhood conditions and adiposity. When analyses were conducted separately by gender, perceived neighbourhood stressors were strongly associated with central obesity measures (waist circumference, waist⁻hip ratio) among both men and women. Our findings indicate that chronic neighbourhood stressors are associated with obesity. Neighbourhood environments are modifiable, and efforts should be directed towards improving deleterious local environments to reduce the prevalence of obesity.

This study investigates the relationship between intergenerational occupational mobility and objective physical functioning in later life.
Data come from The Irish Longitudinal Study of Ageing (TILDA), a nationally representative probability sample of 5,985 respondents aged 50 and older. Walking speed and grip strength are the functional health measures. The intergenerational occupational mobility measure characterizes origin and destination position as: professional/managerial, non-manual, skilled manual/semi-skilled, unskilled, never worked, and farmer.
Results indicated no direct association of childhood origin with walking speed or grip strength in later life, except for individuals from farming backgrounds. Those who experienced upward mobility were comparable in speed and strength with those who enjoyed high status (e.g., stable professional/managerial origin and destination) at both time points, whereas the downwardly mobile were comparable with those who were stable across generations at lower occupational positions. The results did not support the central tenets of the accumulation hypothesis. Respondents from farming backgrounds exhibited a clear performance advantage irrespective of destination, which, we speculate, may represent a critical period effect.
The mechanisms through which childhood origin affects health in later life are complex, but the position attained in adult life is most important. Intergenerational mobility is important only insofar as it leads to a destination occupation. The present findings suggest that the musculoskeletal system may accommodate environmental modification in adulthood.

BACKGROUND: observational studies do not always find positive associations between physical activity and muscle strength despite intervention studies consistently showing that exercise improves strength in older adults. In previous analyses of the MRC National Survey of Health and Development (NSHD), the 1946 British birth cohort, there was no evidence of an association between leisure time physical activity (LTPA) across adulthood and grip strength at age 53. This study tested the hypothesis that cumulative benefits of LTPA across mid-life on grip strength will have emerged by age 60-64.
METHODS: data from the MRC NSHD were used to investigate the associations between LTPA at ages 36, 43, 53 and 60-64 and grip strength at 60-64. Linear regression models were constructed to examine the effect of activity at each age separately and as a cumulative score, including adjustment for potential confounders and testing of life course hypotheses.
RESULTS: there were complete longitudinal data available for 1,645 participants. There was evidence of a cumulative effect of LTPA across mid-life on grip strength at 60-64. Compared with the third of participants who reported the least LTPA participation across the four time points, those in the top third had on average 2.11 kg (95% CI: 0.88, 3.35) stronger grip after adjustments.
CONCLUSIONS: increased levels of LTPA across mid-life were associated with stronger grip at age 60-64, in both men and women. As these associations have emerged since age 53, it suggests that LTPA across adulthood may prevent decline in grip strength in early old age.