Numerous studies have emphasized a stable relationship between subjective age and health. However, few longitudinal studies exist and these have normally tested only one causal pathway. The present study investigated the direction of effects between subjective age and different health dimensions in 3,038 participants of the German Ageing Survey, aged 40 years and older. Cross-sectionally, subjective age correlated with all health dimensions studied. Longitudinally, subjective age predicted physical, mental, and self-rated health, whereas the reverse effect was found only for self-rated health. Subjective age thus seems to be an important resource for preserving health in the second half of life.

Using data from the German Ageing Survey (Deutscher Alterssurvey, DEAS; N = 4,712), this study examined age-related change in three dimensions of self-perceptions of aging (SPA): perceptions of physical losses, social losses, and ongoing development. Participants ranged in age from 40 to 85 years at study entry (1996, 2002, or 2008) and were followed for up to 21 years. Time-invariant, context-specific and timevarying, person-specific predictors of the observed age-related changes were examined. Findings from longitudinal multilevel regression analyses showed significant nonlinear age-related change for all three dimensions. Specifically, starting at about age 65, participants showed age-related increases in perceptions of physical and social losses, with increases getting steeper in old age. Starting at about age 55, participants reported increasingly fewer perceptions related to ongoing development. The decline in perceptions of ongoing development also became increasingly steeper after age 70. Region of residence was a significant context-specific predictor of the intercepts of the three SPA dimensions. Health-related variables (i.e., number of chronic diseases, self-rated health), affective well-being (i.e., positive and negative affect), and measures of social integration (i.e., loneliness) were significant person-specific predictors. Health-related variables had their strongest association with perceptions of physical losses, whereas negative affect and loneliness had their strongest association with perceptions of social losses. Positive affect had its strongest association with perceptions of ongoing development. This study is the first one to describe age-related change trajectories in multiple dimensions of SPA and significant predictors of these change trajectories.

Previous studies have shown that some predictors of self-rated health (SRH) become more important with age, while others become less important. Although based on cross-sectional data, these findings are often interpreted as age-related changes in evaluation criteria. However, results could be due to cohort effects as well. We attempted to disentangle age and cohort effects by combining and comparing cross-sectional and longitudinal data from a large-scale longitudinal survey. The sample consisted of 2,982 community-dwelling participants from 2 measurement occasions of the German Ageing Survey ages 40-81 years at baseline. Multigroup latent regression models were used to examine whether associations between various predictors and SRH differed between age groups and whether they changed over time. Comparisons of cross-sectional age differences in SRH-predictor associations and longitudinal age changes in the same associations allow the identification of cohort effects. Number of chronic conditions showed a constant negative association with SRH independently of age and cohort. In contrast, the association between SRH and all other predictors (physical functioning, exercise, life satisfaction, depressive symptoms, and positive affect) changed longitudinally, pointing to an age effect. Prediction of SRH by depressive symptoms and positive affect showed an additional cohort effect: The negative associations between depressive symptoms and SRH and the positive associations between positive affect and SRH were stronger among younger cohorts. The findings provide not only longitudinal support for previous cross-sectional studies, but also show the impact of historical change: Emotional facets of psychological well-being increase in relevance for SRH across cohorts.

Although a large body of research has demonstrated the predictive power of subjective ageing for several decisive developmental outcomes, there remains some controversy about whether subjective ageing truly represents a unique construct. Thus, information about the convergent and discriminant validity of different approaches to measuring subjective ageing is still critically needed. Using data from the 2014 wave of the German Ageing Survey, we examined how three established subjective ageing measures (subjective age, global attitude toward own ageing, multidimensional ageing-related cognitions) were inter-related as well as distinct from general dispositions (optimism, self-efficacy) and well-being (negative affect, depressive symptoms, self-rated health). Using correlational and multivariate regression analysis, we found that the three subjective ageing measures were significantly inter-related ( r = |.09| to |.30|), and that each measure was distinct from general dispositions and well-being. The overlap with dispositional and well-being measures was lowest for subjective age and highest for global attitudes towards own ageing. The correlation between global attitudes towards own ageing and optimism was particularly striking. Despite the high convergent validity of the different dimensions of ageing cognitions, we nevertheless observed stronger associations between specific dimensions of ageing cognitions with negative affect and self-rated health. We conclude that researchers should be aware of the multidimensional nature of subjective ageing. Furthermore, subjective age appears to be a highly aggregated construct and future work is needed to clarify its correlates and reference points. Electronic supplementary material The online version of this article (10.1007/s10433-019-00529-7) contains supplementary material, which is available to authorized users.

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