This study explored the degree to which lifestyle behaviours, such as alcohol consumption, smoking, physical and social activity, and nutrition habits are associated with higher future PWH in a large representative sample of middle-aged and elderly Lithuanian urban population. Never smoking in men and former smoking in women, higher physical activity in women, high social activity and more frequent intake of vegetables and fruit in men and women were positively associated with higher PWB after adjusting for several covariates. Furthermore, a positive effect was observed between the baseline protective health behaviour score and higher PWB during 10-year follow-up.
Our study results extend those of previous research which also found positive relationship between lifestyle factors and good mental health, including higher PWB [12, 14, 36]. Importantly, our study shows that those associations were present even after statistical adjustment for several covariates such as biological factors, socioeconomic and sociodemographic factors, other mental health indicators (depressive symptoms) and chronic disease (coronary heart disease).
According to the WHO, healthy lifestyle means regular physical activity, no smoking, refusal of alcohol, healthy eating and avoiding being overweight. Such behavior should lead not only to better physical and mental health but also to well-being . Recent prospective studies have found a two-way association between lifestyle and mental and emotional health and well-being . Healthy lifestyle features can have a positive effect on the development of depression and anxiety, life satisfaction and self-perceived general mental health .
Changes in body weight could be one of the biological factors associated with well-being, mental health and higher PWB. According to Stranges et al., underweight is inversely associated with well-being and overweight is positively associated with well-being . This may be due to the fact that persons who are underweight may have other metabolic or digestive disorders that can lead to a lack of certain essential substances and hormones in the body, which in turn can lead to certain mental health problems. These data suggest a U-shaped association between BMI and well-being, and, at the same time, overweight has a protective effect on emotional well-being. There are limited data on the association between obesity, mental health, and dietary habits. According to Meegan A.P., the association between nutritional quality and well-being has been identified and remains significant only in non-obese individuals. No association or symptoms of anxiety were observed among obese individuals . In addition, Jacka et al. data suggest that an inverse causal association may explain the links between diet and mental health . Thus, it is clear that the associations between nutrition, overweight and mental health are very complex. Further cohort prospective studies that would examine these associations and focus on the reverse causality hypothesis are needed to further determine the direction and underlying causal mechanisms of these associations.
The relationship between nutrition habits and mental health, including PWB, is quite extensively studied. Most of previous studies, similarly to our study, considered vegetables and fruit as a combined food group [9, 41]. Only some studies have assessed the impact of vegetables and fruit as an independent food group in the regression models [42, 43]. The findings from these studies demonstrate that the effect of consumption of vegetables on PWB was greater when compared to the consumption of fruit. The results of the exploratory factor analysis of the CoLaus / PsyCoLaus study (Lausanne, Switzerland) showed that the “Sweet-Dairy” diet (mainly chocolate, biscuits, pastries, cakes, butter, high-fat and low-fat dairy products, jam, and honey) was positively related to melancholic depression . In contrast, our data show that the consumption of sweets was significantly related to higher PWB in men but not in women. We found that an increase in the frequency of consumption of potatoes, meat, boiled vegetables, and eggs was related to significantly lower odds of higher PWB in women. Our data contrasts with previous research showing that not only fresh vegetables and fruit but also processed vegetables and fruit (dried or canned) are associated with better mental health [45, 46]. Healthy eating patterns, such as those in the Mediterranean and some Nordic countries, which are characterized by high consumption of vegetables and fruits, whole grains, lean fish, and meat, have been associated with a reduced risk of depressive complaints . Meanwhile, an unhealthy diet, characterized by increased consumption of processed meat, fatty foods, refined grains, high-sugar products, and alcohol, has been associated with an increased risk of depression and poorer mental health . According to the data of other recent studies, among women and men high consumption of fruit and vegetables, moderate consumption of dairy, and moderate-high intake of meat were negatively associated with mental distress and improved mental health and cognitive function , whereas high fast-food and caffeine consumption was positively associated with mental distress .
Our data indicate that in men, compared to current smokers, being a never-smoker was associated with an increased probability of higher PWB in partially and fully adjusted models. Similar result was found among women when former smokers were compared to current smokers (OR = 1.67, p < 0.05 and OR = 1.91, p < 0.05 for partially and fully adjusted models respectively). In contrast, among 13,983 adults 16+ of age from England, reduced ORs of good mental well-being were determined among former smokers. The authors attributed this finding to the fact that smoking cessation may have been a consequence of the underlying disease rather than a preventive measure. Such an effect has not been taken into account by other researchers . To date, most of the studies have shown that individuals who never smoked or stopped smoking demonstrate a significant increase in positive PWB compared to the individuals who continue smoking [49,50,51]. Other researchers have also found that smoking is linked to greater mental health problems. In a prospective study, subjects who continued to smoke had increased symptoms of depression, anxiety, and stress . After quitting smoking, more time is made available for other lifestyle-related activities, such as physical or social activity, which are linked to better emotional well-being and better mental health. Further promotion of quitting smoking programs can help to stop smoking and thus improve not only a person’s physical but also his/her mental health .
Results from epidemiological studies of the relationship between alcohol consumption and mental health including PWB are controversial. Findings in some studies show a U-shaped association indicating a better PWB or lower risk of mental health outcomes among moderate drinkers of alcohol in comparison with abstainers or never drinkers and heavy drinkers [36, 53, 54]. In the study of New Zealand adults, drinkers of alcohol once a month or less, compared to drinkers up to 4 times per month, had significantly lower odds of optimal well-being in crude, partially adjusted and fully adjusted binary logistic regression models . In contrast, other studies have not found significant association between alcohol consumption and well-being or found it only after applying crude but not adjusted regression models [15, 50]. Our study also revealed no significant relationship between alcohol consumption and PWB. However, the following tendency was observed: decreased frequency of alcohol consumption was associated with lower odds of higher PWB in comparison with everyday alcohol drinkers. This may be related to the fact that after 10 years, the subjects’ reduced alcohol consumption is associated with lifestyle changes due to other chronic health conditions that could lead to changes in both physical and mental health, and the same time, to a lower PWB.
Social activities, including engagement in cultural events, arts, sports, and other clubs, in relation to mental health and well-being are quite widely explored in epidemiological studies. Findings from 5338 adults examined in the UK showed that more arts engagement was associated with higher levels of well-being and social connectedness, lower odds of intense social loneliness and, in contrast, positively related with depression and intense emotional loneliness . Mental activities, including making music, going to the cinema or theatres, reading books, were positively related with positive mental health at baseline survey but not at 1-year follow-up survey using matched data of German and Chinese students . In the present study, moderate and high social activity (participation in clubs, visiting the church, theatres, restaurants, and other cultural events) was significantly related to higher future PWB both for men and women compared to low social activity individuals. One explanation could be that individuals who are socially active have greater physical activity, which has a positive effect on both physical and mental health and increases well-being. It cannot be ruled out that the traits of an individual study depend on genotype and character traits, and certain sociodemographic components such as marital status, education, and socioeconomic conditions. Frequent loneliness, lower education, lack of income, unemployment were associated with lower social activity and increased the risk of depression, at the same time worsening mental health and well-being [56,57,58].
The positive effect of physical activity on mental health is attributed to the release of endorphins which help to boost well-being and increase energy . A higher level of physical activity has been linked with reduced risk of mental health outcomes and better PWB [14, 49, 60]. In young women (aged 18 to 29 years) and mature women (aged 30 years and older), high frequency of physical exercise was significantly associated with mental well-being. In young men but not in mature men, frequent exercise was negatively related with mental distress . Our data indicates that among women physically active individuals showed significantly higher odds (OR = 1.34, p < 0.05) of better PWB in comparison with those people who were physically inactive but only in partially adjusted regression model. In men, no association between physical activity and future higher PWB was observed. This can be explained by the fact that most men worked physically and that higher physical activity could not have had a greater effect on higher PWB during the study period despite the older age of the men studied.
The combined effect of several risk factors on all-cause and CVD mortality has been quite widely explored and is associated with higher mortality rates [61, 62]. The relationship between healthy levels of biological factors and healthy lifestyle behaviours and both physical health and mental health was less intensively examined [34, 63, 64]. In the sample of 25,837 participants from the NutriNet-Sante (France) study, after a mean follow-up of 5 years, incidence of depressive symptoms in individuals having 5 healthy lifestyle indicators was significantly lower by 25% compared to individuals having 0–2 indicators . Other recent studies have found that a higher healthy lifestyle score was associated with lower overall mortality [2, 3]. Our findings show that in men, a greater number of healthy lifestyle behaviour (3 to 6) was associated with significantly higher odds of higher PWB after 10-year follow-up in comparison with men having 0–2 healthy lifestyle behaviour factors with adjustment to several confounders in the regression model. In women, significant relationship between the score of healthy lifestyle behaviour and higher PWB was determined only when individuals having 0–2 and 6 such factors were compared.
Strengths and limitations
Strengths of the present study are its prospective design, large sample size and wide age interval of study participants including middle-aged and elderly individuals (45–72 years at baseline). Other strengths are data collection using standardized and validated study methods, long follow-up period (from 2006 to 2008 to 2016) and many potential confounders included into statistical analyses (up to 13 variables in fully adjusted multivariate regression models). This study also has some limitations. First, we do not know exactly what diseases or additional health disorders our subjects had during the follow-up period, and what new risk factors for chronic diseases and harmful lifestyles emerged during that period, and for how long. Secondly, lifestyle behaviours and PWB were self-reported by study participants who may have been affected by recall bias and this could have resulted in overestimation or underestimation of the determined outcomes. Thirdly, we included traditional lifestyle behaviour factors in this study. Factors, especially the so-called non-traditional lifestyle factors (sleep duration, quality of sleep, sedentary lifestyle, and other factors), that were not included in our study could also be related to PWB. Finally, caution should be exercised when generalizing our findings to the Lithuanian population, as only Kaunas city residents were included in the random sample of our study.