Hot topics in ageing research

Large prospective cohort studies with follow-up periods extending up to over forty years, as well as recent qualitative randomized controlled trials (RCTs) have provided groundbreaking new knowledge on lifestyle factors that contribute to old age health and functioning. These studies highlight the importance of a life-course perspective when aiming to promote a healthy and active old age. One of the recent interests in Finnish ageing research has been occupational gerontology. It refers to research that investigates the relationship between working life and old age (Goedhard 2011). It provides knowledge on how to promote the work ability of older workers and it also investigates, whether working life and working conditions have longitudinal effects on later life health outcomes. The research area provides further understanding how working life affects life after retirement.

The Finnish Longitudinal study on Municipal Employees (FLAME) is an ongoing prospective longitudinal study. The study was initiated by the Finnish Institute of Occupational Health in 1981 and is currently a collaboration study in which several research institutes in Finland participate. The baseline cohort in the beginning of 1980s consisted of 6257 occupationally active middle-aged persons, whose work ability, working conditions and health-related factors were assessed with postal questionnaires (Tuomi et al. 1997). This cohort has been followed for almost thirty years, which has provided a unique opportunity to assess the long-term effects of working life. The FLAME study has resulted in several interesting findings. For example, studies published in 2013-2014 showed that perceived work-related stress significantly increases the risk of old age functional and mobility decline (Kulmala et al. 2013). Compared to persons who did not report work-related stress in midlife, those who suffered from stress symptoms during their working life, such as negative reactions to work and depressiveness, perceived decrease in cognition, sleep disturbances or somatic stress symptoms, had a significantly higher risk of developing difficulties in walking and mobility as well as difficulties in basic and instrumental activities of daily life in old age.

In addition to mental stress, physically straining work was associated with poorer physical functioning in old age (Hinrichs et al. 2014). The FLAME study has also provided evidence that mental and physical strain during work may modify the future mortality risk. The results published in 2012 showed that low job control in men increased, whereas high job demand in women decreased the mortality risk during the following decades (von Bonsdorff et al. 2012). These findings clearly demonstrated that unfavorable working conditions may have detrimental effects on health in later life and also increase the vulnerability of the elderly for physical disabilities or even premature death.

Finland has also been one of the leading countries in dementia prevention studies. Large prospective studies with follow-up periods extending up to thirty years have provided knowledge on several lifestyle factors that either increase or decrease the dementia risk (physical activity and fitness, dietary factors and cardiovascular risk factors). Recently, Finland has gained wide national and international attention after publishing the results from the large randomized controlled trial FINGER (Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability) in the highly respected medical journal the Lancet. The FINGER study is the first large randomized controlled trial in the world that showed that multidomain lifestyle- based intervention (changes in diet, increasing physical activity, cognitive training and vascular risk monitoring), significantly decreases the risk of old age cognitive decline (Ngandu et al. 2015). These results gave the first scientific evidence that by modifying the lifestyle habits of the elderly, it may be possible to maintain cognitive capacity in later life. Since dementia is one of the main public health concerns in Finland and also across the world, these findings give hope that cognitive decline and dementia may be partly prevented, or at least that the onset of the disease may possibly be postponed.

As briefly described above, several earlier - work-related - life events and lifestyle factors are key determinants of a healthy and active old age. In order to investigate these lifestyle effects in relation to old age health and functioning, there is a need for large population- based datasets, where the same persons have been followed for several decades. It also requires well-conducted randomized controlled trials in order to really test the effects of interventions. This kind of research provides opportunities to identify the risk and protective factors and causal pathways that influence old age health and wellbeing. Finland has a long tradition in conducting such studies, and prospective large population- based datasets used in the Finnish aging studies are rare worldwide. Finnish well-organized register-based data also give unique research possibilities. Several studies related to ageing and life-course epidemiology are currently in progress in Finland. Therefore, remarkable research news is also expected in the future.