Although aging is considered above all a biological process, aging with quality of life is a biopsychosocial process. In fact, old age does not merely portray only a biological landmark. This is a life period characterized by marked social and psychological transformations, where various social and contextual factors interact: life conditions, family situation, support structures, personal expectations, among others . In this context, aging and the way it is experienced by everyone is a process of great complexity, of individual experiences, deeply marked and influenced by external factors.
Therefore, the promotion of QoL in elders is a challenge for health and social care professionals. In order to understand the simultaneous relationship between modifiable (psychological variables) and non-modifiable variables (sociodemographic), and QoL in the elderly, a path analysis model was performed in order to guide and inform social, health and education policies.
As expected, individual characteristics showed a direct impact on physical and mental QoL. The presence of chronic disease had a negative impact on the PQL  and is inversely associated with quality of life in the different domains: the elderly without any diseases present a significantly better quality of life  as well as the age of the individuals, i.e., older individuals had lower MQL. Being aging as a biological process this result makes an intuitive sense [29–31].
Interestingly, spirituality was the only variable to have a negative direct effect on MQL, emphasizing the role of spirituality on mental quality of life. In the face of aging, the difficulties inherent in the aging process and the inevitable sense of finitude, spirituality and religion appear as a support that helps the elderly to counter the tendency to isolation and overcome the problems of daily life .
In this study, was evaluated the how spirituality helps dealing with this chronic disease, and, although most of this population reported having a chronic illness, however it is verified that their degree of autonomy is high. Thus, this chronic disease doesn’t cause or increase disability allowing the maintenance of the capacity to carry out their daily tasks. In fact, this older people don’t feel the need to search in God or in High power the support for adjust, find a meaning and understand her disease .
However, functionality showed an indirect effect in MQL being mediated by social support. Social support is a recognized mediator between functional status and QoL [32, 33], being a resource to reduce adverse outcomes in older adults. Social support was a mediator between functional status and MQL emphasizing the importance to promote this resource in this population. Formal and informal groups are a way to enhance social participation, which has been pointed as an effective factor to improve the mental health of the older people . Older adults who perceive a high social support show beneficial effects on enjoyment, morale, depression and loneliness .
Finally, in this model, the mental quality of life had a direct effect on physical quality of life of individuals. This result is interesting given that this relationship should be bidirectional but, in this sample, it seems that MQL affects PQL and not on the other way.
The results reinforce the need to address the individuals with chronic diseases, with a systematic and individualized social and health care.
Physical activity should be promoted by institutions social network for the elderly as well as in the community such as churches and community gyms, in order to improve functionality and skills for daily activities due to the direct effect on PQL. Several studies have suggested that the level of physical activity recommended by WHO has a positive impact on QoL , especially with effects on general health, social function and mental health . In addition, physical activity may protect against the cognitive decline characteristic of this population .
Finally, the fact that MQL affects PQL indicates that emotional well-being is an important topic to include in quality of life promotion programs for the elderly. Emotional support groups and leisure activities are healthy lifestyles that should be included in interventions programs . Strategies such as reminiscence, theater, etc., can be productive in promoting the quality of mental life. In addition, social relations and leisure activities are associated with better health in the elderly . These results highlight the importance of developing psychosocial intervention programs and at the level of health promotion that include strategies to develop functionality and social support in order to improve the quality of life of the elderly.
This study has some limitations that must be acknowledge. The sample is limited to a geographical area where socio-cultural characteristics of urban and rural nature are mixed, that is, this area cannot be classified as entirely rural or urban, giving rise to limitations in extrapolating results to entirely urban or rural areas. The population surveyed, being representative of the Tâmega and Sousa region, is not representative of the country.
Other limitations stem from the extent of the survey applied. The data collection instrument used involved some extension, becoming difficult to apply and demanding attention to the respondents, which given the characteristics of low education of the population under study caused some difficulties in the interpretation of the questions. However, this study represents an important contribution to the identification of the main social and clinical characteristics of the elderly population of a zone of the interior of Portugal that demands answers adapted to their needs.
However, this study represents an important contribution to the identification of the main social and clinical characteristics of the elderly population of a zone of the interior of Portugal that demands answers adapted to their needs.