An invisible villain: high perceived stress, its associated factors, and possible consequences in a population-based survey in southern Brazil

Abstract Introduction Much of the evidence on the relationship between stress, lifestyle, and other physical and mental health outcomes comes from studies conducted in high-income countries. There is therefore a need for research among populations in low and middle-income settings. Objectives To measure stress levels and identify factors associated with a high stress level and its consequences for health. Methods This was a population-based cross-sectional study carried out in 2016 with adults aged 18 years or older in a municipality in southern Brazil. A two-stage sampling strategy based on census tracts was used. Stress levels were measured with the Perceived Stress Scale (PSS-14) and classified into quartiles. The impact of the highest stress levelon each outcome was assessed with etiologic fractions (EF). Results The most stressed groups were: females (PR = 1.51, 95%CI 1.25-1.81), younger people (PR = 1.76, 95%CI 1.26-2.46), middle-aged individuals (PR = 1.60, 95%CI 1.17-2.19), those with lower schooling (PR = 1.56, 95%CI 1.20-2.02), the physically inactive (PR = 1.51, 95%CI 1.20-1.91), people who spent three or more hours watching television per day (PR = 1.29, 95%CI 1.12-1.50), and those with food insecurity (PR = 1.44, 95%CI 1.19-175). Possible consequences of high stress level were regular or poor self-perception of health (EF = 29.6%), poor or very poor sleep quality (EF = 17.3%), lower quality of life (EF = 45.6%), sadness (EF = 24.2%), and depressive symptoms (EF = 35.8%). Conclusions Stress plays an important role in several domains of health. Both public policies that target reduction of inequalities and specific stress-management interventions can reduce stress levels in populations, thereby decreasing the burden of other negative physical and mental health outcomes related to stress.


Introduction
Stress can be defined as the body's response pattern to external demands, regardless of the nature of the causative agent, and the implications of stress are of considerable interest in health research. 1 While responses to acute stress are adaptive, chronic stress can predispose individuals to a lower quality of life and increased health problems. 2 Evidence indicates that stress can hinder development of a healthy lifestyle.
People under stress are more likely to adopt harmful health behaviors, such as physical inactivity, smoking, and drinking alcoholic beverages. 3 Stress seems to have a complex and bidirectional relationship with mental disorders, especially depression. 4 Much of the available evidence on the relationship between stress, lifestyle, and other physical and mental health outcomes comes from studies conducted in high-income countries. [5][6][7] There is therefore a need for research among populations in low and middle-income settings. There are also complex interrelations between individual (gender, education, occupation, income, behaviors) and contextual factors (structure, culture, and values of the region or country in which one lives) that predispose a person to be more stressed. Failure to account for these mechanisms may lead to incomplete interpretations of possible adverse outcomes resulting from stress.
High levels of perceived stress have been associated with poorer overall physical and mental health, in addition to increased risk of premature death. 6 Investigating the association between psychological stress and health-related outcomes is of foremost relevance. Mapping how stress can be shaped according to individuals' characteristics and to modifiable lifestyle behaviors, as well as its effects, can provide health professionals and key stakeholders with helpful insights and information for development of better health plans, policies, and practices. Therefore, the objective of the present study was to identify the social, economic, demographic, and behavioral factors that are associated with perceived stress and to investigate the possible consequences of stress for the physical and mental health of the population of a municipality in southern Brazil.

Study design
This cross-sectional study is part of a populationbased study, titled "Health of the Population of Rio

Variables and instruments
The outcome was perceived stress, measured using the Perceived Stress Scale, 10 which is a 14-item instrument that assesses the frequency with which an individual has experienced certain feelings and situations. This scale has been translated and validated for use in the Brazilian setting. 11 A Likert scale was used, with response options ranging from 0 (never) to 4 (always) points. A total score ranging from 0 to 56 points is generated by summing the scores for all questions.

Data analysis
The statistical analyses were conducted in Stata 15.1.
First, a descriptive analysis of sample characteristics was performed. After this step, bivariate analyses were performed to calculate the proportions of highly

Data availability statement
We declare that the data used in this manuscript is available upon request from the corresponding author.

Results
The

Main finding of this study
This study evaluated perceived stress levels

What is already known on this topic?
The stress scores reported in studies conducted in low and middle-income countries, such as Jordan (17.7) 19 and India (19.3) 20 were lower than that those found in this study. However, the scores reported in high-income countries, such as Italy (15.2), Germany (14.9), France (15.0), and Poland (17.6) were higher than that found in our study. 21 In addition, the mean score for perceived stress in our investigation was similar to the score reported in a study conducted in Greece (25.4), 21  There is evidence that women report being more stressed than men, 22 possibly due to hormonal influences and social issues, 23 such as the devaluation of their work, the need for more working hours, and the objectification of their bodies. 24 Studies indicate that older people have lower levels of anxiety, depression and stress, as well as higher levels of happiness, satisfaction, and well-being, 25,26 which can be explained by an increase in wisdom and an increased ability to deal with daily life stressors. 27 Finally, individuals with less education may have greater difficulty finding optimal occupations and attaining higher socioeconomic status, which may expose them to greater and more persistent psychosocial stressors. 28 Physical activity has a bidirectional relationship with stress, since physically active individuals tend to be less stressed and, consequently, are more likely to remain active. 29 Individuals who spend more time in front of television tend to have higher levels of sedentary behavior (i.e., sitting and/or lying down), 30 which has also been strongly associated with high levels of stress. 31 Respondents with food insecurity may experience higher levels of prolonged and toxic stress, as they lack basic resources for survival and citizenship. 32 Furthermore, food insecurity may result in insufficient intake of nutrients, generating physiological sequelae that may predispose individuals to psychological suffering. 32,33 With respect to the finding about obesity, the initial hypothesis was that individuals with high levels of stress would be more prone to obesity, since stress plays a role in its development and maintenance. 34 Notwithstanding, the results found in this study may have occurred due to two phenomena. First, individuals who eat for comfort seem to achieve lower levels of perceived stress, which could result in people with higher BMI having lower perceived stress scores. 35 Second, the results may be due to a negative confounding effect, because obese people tend to have a worse perception of health, 36 are sadder and more depressed, 37 and have worse quality of sleep 38 and quality of life. 39 It is therefore plausible that when we control for these variables in multivariate analysis, obese people can, in fact, be less stressed.
The association between stress level and poorer self-perceived health corroborates the literature that emphasizes that self-perceived health can be referred to as a health indicator. 40

Limitations of this study
The findings of this investigation should be interpreted in light of its limitations. First, all variables were measured through self-report, which might produce less precise results. However, most large-scale epidemiological studies collect data using self-report