Introduction
The prevalence of depressive symptoms within the elderly population is quite high [
1,
2]. Moreover, depressive symptoms in elderly adults tend to coincide with physical illness [
3]. Higher levels of depressive symptoms often predict mortality in elderly people. This association is being explained by the comorbidity of physical illness [
4]. However, some population-based studies show that depressive symptoms predict mortality even when co-occurrence of physical illness is being controlled [
5].
Previous studies have revealed many correlates of depressive symptoms, the most commonly known being sex. Previous studies reveal that the prevalence of depressive symptoms is higher in women compared to men [
1,
6,
7]. Marital status is also important—marriage works as a preventative factor for depressive symptoms, especially for men [
4]. Depressive symptoms in Eastern Europe are also associated with current socioeconomic status measured by education level, deprivation, and crowding [
8]. An especially high prevalence of depressive symptoms can be found within deprived populations [
9].
Depressive symptoms are closely correlated with quality of life [
10‐
12]. It is difficult to affirm cause and effect; however, some explanations have been suggested. The first is that participants with depressive symptoms perceive their quality of life as lower because of their lowered mood [
13]. Also, older age with increased prevalence of chronic health problems is associated with lower quality of life [
14]. Thus it might be that participants, because of long-term health problems, perceive their quality of life as lower.
In the elderly population, depressive symptoms are associated with self-evaluated health problems and a history of chronic diseases [
6]. Previous studies have established that chronic diseases in older age lead to depressive symptoms [
14,
15]. Depressive symptoms are more common in patients with asthma [
16], respiratory diseases [
17], cardiovascular diseases [
5], and diabetes [
18]. It is clear that depressive symptoms are associated with chronic illness. Associations become more severe with increasing quantity of chronic illness and chronicity; however, chronic illness does not explain all depressive symptoms [
19]. Associations are not clear enough and previous studies found many differences due to sex or other covariates. Another hypothesis is that depressive symptoms are associated with a lower level of self-rated health because depressed patients subjectively perceive their health to be worse [
13].
Depressive symptoms are also associated with health-related behavior. A great number of studies suggest that physical activity and exercise are inversely correlated with depressive symptoms [
20]. The relationship between alcohol consumption and depressive symptoms is still unclear; some studies show that depressed participants tended to use alcohol more frequently [
1], others posit that those two factors are not associated [
21].
Many studies were done to explore the links between depressive symptoms, chronic illness, self-rated health or quality of life, lifestyle factors, and sociodemographic factors. Still, there is no clear answer about the correlates of depressive symptoms. Results differ because of population characteristics or the influence of other covariates. The purpose of this study is to examine the prevalence of depressive symptoms and their correlates in urban middle-aged and elderly Lithuanian adults.
Discussion
As was found in the findings above, the prevalence of depressive symptoms in the middle-aged and elderly population is quite high [
1,
2]. In our sample it was 23.4 %. Comparatively, the prevalence of depressive symptoms amongst older adults in China ranges from 12.8 to 41.1 % [
2]. In Eastern European countries like Russia, Poland, and the Czech Republic, the prevalence of depressive symptoms is about 20 % in men and 40 % in women [
1]. Our results corroborated previous studies that conclude that the prevalence of depressive symptoms is higher in women (29.9 %) compared to men (15.6 %) [
9], although this may be because women might be more willing to express their emotions and negative feelings. It is also hypothesized that women tend to show more depressive symptoms due to health problems as they might be more sensitive to them [
29]. However, different studies show that men are more overwhelmed with health problems and limitations to everyday activity [
30]. Other studies show that, with all covariates controlled for, sex is still effective as an important factor for depressive symptoms [
9,
31].
Age was correlated with depressive symptoms only in univariate analysis. Women showed more depressive symptoms in the older age group than the younger one. However, when all covariates were controlled for, age lost its effect on depressive symptoms, similar to previous studies [
2]. This observation might be explained by the fact that the prevalence of depressive symptoms is higher in older participants because they have more chronic health problems than younger adults [
9].
Marital status was associated with depressive symptoms for both men and women. Univariate analysis established that there were more participants with depressive symptoms in the “single”, “divorced”, and “widowed” groups than the “married” one. Even in multivariate analysis, marital status was important. Widowed participants had increased odds of having a higher level of depressive symptoms. Divorced men also tended to have a higher prevalence of depressive symptoms. As in previous studies, marriage worked as a preventative factor compared to those who have been divorced or widowed, especially for men [
4]. It is perhaps understandable that widowers tend to be more depressed because of feelings of sorrow or loneliness.
Previous research has established different links between crowding and depressive symptoms. In similar populations to Lithuania like those of Russia, Poland, and Czech Republic no significant associations were found [
32]. However, a study performed in North Carolina, in the immigrant Latino population, connected depressive symptoms to crowding. More crowded housing was associated with depressive symptoms [
33]. In contrast, in our study, participants who have had depressive symptoms tend to live in less crowded houses. However, this link is not significant in multivariate analysis when deprivation and marital status were controlled for. It might be that crowding in our research was more connected to an indicator of marital status and less to an indicator of deprivation, so it did not indicate socioeconomic status.
Deprivation increases the probability of having depressive symptoms. In multivariate analysis, when all the risk factors were controlled for, deprivation still increased the odds of having higher levels of depressive symptoms in both the male and female groups. It confirms previous study results that depressive symptoms are associated with poor economic status [
2,
8,
9]. The authors explain that people with lower socioeconomic status have fewer financial possibilities to reach their desired goals and to realize their potential, which is a circumstance connected to their psychological well-being [
34]. We also suggest that because of their financial difficulties, their ability to solve health-related problems is affected, which in turn increases their chance of expressing depressive symptoms.
Health-related risk factors were differently connected to depressive symptoms in the male and female groups. Overweight and obese women tended to have more depressive symptoms, whereas this difference was not established in the male group. As a previous study shows, obesity is a risk factor for depressive symptoms only in women. This is probably because overweight women are stigmatized more than men [
21]. In the univariate analysis, being a smoker was associated with depressive symptoms only in the male group; however, the same study in Japan revealed that smoking is a risk factor for developing depressive symptoms in women, too [
21]. Our results might differ because of a very low incidence of smoking amongst the women in our analyzed age group. Our results established that a bigger dose of alcohol is connected with depressive symptoms in women, although the study in Japan revealed that alcohol consumption is not correlated with depression [
21]. In countries closer to Lithuania, such as Russia, Czech Republic, and Poland, similar results were found to those in our study [
2]. Physical inactivity in leisure time also increased the odds of having depressive symptoms in both men and women, which is an association confirmed by previous studies [
20,
35].
In univariate analysis, all chronic diseases were connected to having depressive symptoms. Arterial hypertension, diabetes, IHD, long-term health problems, chronic respiratory disease, cancer, gallbladder disease, kidney stones, asthma, and disease of the spine and joints were all linked to depressive symptoms. These results reaffirm previous findings that established a link between depression and problems such as asthma [
16], respiratory diseases [
17], cardiovascular diseases [
5], and diabetes [
18]. In our study, arterial hypertension and cancer were connected to depressive symptoms only in female participants. Another study also concluded that amongst many chronic diseases, only cancer and hypertension were not linked to depressive symptoms in the study sample [
3].
Our study showed that even controlling for sociodemographic factors and long-term health problems, a low quality of life was strongly associated with depressive symptoms, as shown in previous studies [
12]. Health problems alone cannot explain association between quality of life and depressive symptoms. Although all chronic conditions were related with depressive symptoms in the univariate analysis, when controlling for self-rated quality of life and physical health associations, they lost their significance. Similar results were found in a study of the elderly Chinese population. In the bivariate analysis, depressive symptoms were associated with a higher number of chronic diseases and lower self-rated physical health. However, in multivariate analysis, only self-rated health was still a significant factor, which indicates that chronic disease might be a covariant of physical health and less relevant to depressive symptoms [
2]. Authors of another study posit that multimorbidity and depressive symptoms are partially mediated by self-rated quality of life and self-rated health [
3]. In conjunction with previous results, our study shows that for further studies and clinical implications, the main focus should be a general association of depressive symptoms and multiple chronic health conditions and not searching for specific links. The main target of further studies should be to understand the whole picture of interactions between depressive symptoms, self-rated health, and physical health status.
Although this study focused on many health indicators, lifestyle factors, and sociodemographic factors, and although the sample was representative, it has some limitations also. We used a self-reporting questionnaire to evaluate depressive symptoms, lifestyle factors, and health status, so mood could well have influenced the answers of participants at the time of filling out the questionnaire. As depressive symptoms were measured according to the participants’ perceptions during the last week, stressful life events could have an influence on it also. Moreover, the data was collected in 2006 to 2008—this limitation should be taken into account by the reader, even if it is unlikely that the association between health status and depressive symptoms has since changed.