Well-being and mental stress in the population study of women in Gothenburg, Sweden: cohort comparisons from 1980 to 2016 of 36-year trends and socioeconomic disparities in 38-and 50-year old women

Women’s life situations have dramatically changed in recent decades, in terms of education, employment, and own income. In a large WHO survey in 2004, data from 57 countries showed that self-reported health in 18–70 year old women was significantly lower than in men at all ages [1]. In Sweden, improvements in women’s health have been documented in the National Public Health Report from 2005 [2], which showed that female life expectancy has increased by 2 years since 1990. However, social disparities in life expectancy increased in 1986 to 2007 in Sweden, especially among women [3]. The same report also showed that stressful work environments have become more common especially for women. This is most prevalent in public sector workplaces such as healthcare, nursing and teaching, all of which predominantly employ women. In Gothenburg, Sweden, an increasing proportion of the female population state that they experience anxiety and mental stress, around 75% in 2004, compared to 25% in the 1960’s [4]. During a similar time period it was reported that the stress-levels in 50-year-old men were unchanged and continuously low, 17% [5].

In 1974, Sweden was the first Nordic country to introduce the law on parental insurance for both women and men [6], which greatly facilitated return to work outside the home after the mother’s parental leave. Another major change in women’s life situation in Sweden is the increasing mean age at first birth, which has risen from 24 years in 1980 to 28.5 years in 2006 and 28.6 in 2016 [7]. These changes have resulted in a transformation of the Swedish family in modern society [6].

In recent decades, a shift has also been observed in women’s perceived moods. In earlier generations of middle-aged women, family conditions were associated with women’s perceived mood, whereas for later generations, her situation at work was most significantly associated with their perceptions of mood [8]. Women’s work situation itself is greatly changed [9]. Increased educational opportunities and changing economic resources have affected employment possibilities for middle-aged women, resulting in changes in their employment rates. In the 1970’s less than 50% of women had full-time employment, compared to 75% in 2016. Corresponding rates of full time employment among men was 92% [10].

Perceived health, well-being and mental stress are closely related factors but the associations are complex and may have bi-directional components [11]. Moreover, reported associations between perceived stress on health and mortality [12] may be dependent on the type of stress and individual responses to stress. Given the changing lives and lifestyles of contemporary women, it is of particular interest to distinguish trends in well-being from trends in perceived stress and to view both factors in the context of socioeconomic conditions.

In the Prospective Population Study of Women in Gothenburg, three population-based samples of middle-aged women (38- and 50-year-olds) have participated in physical examinations with questionnaires on lifestyle in order to document secular trends in cardiovascular health indicators [13, 14]. These samples were recruited in 1980, 2004 and 2016, based on specific dates and years of birth, and answered identical questions on their well-being and perceived stress. Several cardiovascular risk factors related to lifestyle, i.e. smoking, blood lipid levels, and blood pressure levels, were improved in the middle-aged women in the latest decades [14]. A study concerning association between physical activity and well-being showed associations between high physical activity levels and increased well-being in women [15]. Trends concerning well-being in middle-aged women have also been studied in other populations [16]. However, relationships between socioeconomic position, well-being and perceived mental stress have been studied less frequently, and it is not known whether the trends are uniform in different socioeconomic groups of women over time.

Our results showed that the proportion of 50-year-old women who perceived their well-being as good increased significantly from 1980 to 2016. In contrast, no significant differences were seen regarding perception of well-being in 38-year-old women. The percentage of women perceiving high mental stress was significantly higher in 2016 than in 1980 in both 38-and 50-year-old women. Interestingly, later-born 50-year old cohorts experienced increasing well-being over time despite simultaneous increases in stress.

Belonging to a low socio-occupational group was associated with perceived poor well-being in 1980 but not in 2016. In other words, there was a suggestive trend over time, such that low socio-occupational group as a risk factor for poor well-being disappeared from 1980 to 2016. Low socio-occupational group was not a risk factor for high perceived mental stress; no associations were found in 1980, 2004 and in 2016.

It should be noted that the aim was to examine self-reported well-being, rather than mortality and morbidity endpoints. Other studies have clearly demonstrated that subjective self-rated health is a good predictor of use of health care/mortality [26] and metabolic health [27].

The strengths of this study are its long duration and the stability of the examination protocols, which have been maintained over a long period of time (36 years). In particular, the similarity of the questionnaires used by the examining physicians allowed us to compare responses over time to the greatest extent possible. Moreover, the participants were sampled on a population basis, based on specified dates of each birth, and satisfactory participation rates at all survey years improves the generalizability of our observations regarding well-being and mental stress in different SEP groups.

However, one limitation of the study is that the participation rate declined from 1980 to 2016 (Fig. 1), such that 84% of invited women participated in 1980, compared to 59% in 2004 and 68% in 2016. Thus, the time- trends may be over- or under-estimated due to variations in participation. A comparison of participants and non-participants was conducted in 2004, because of the declining participation rate [14]. There were no differences in marital status, hospital admission rate or places of living between participants and non-participants. However, significant differences were observed concerning income and immigration status, with lower mean income and higher proportion of immigrants in the non-participant group. Specifically regarding secular trends in mental stress, it should be noted that the concept of mental stress may have changed or become more normalized between 1980 and 2016, and could explain in part some of the increases. Even in 1980, the observed rates were much higher than in the late 1960’s, when the concept of mental stress was less popularized.

Our results on secular trends in well-being are to a large extent consistent with another longitudinal study from SALLS (Swedish Annual Level of Living Survey) [16]. Improved self-rated health was seen in men and women, aged > 48 years between 1980 and 2004, but self-rated health became poorer or was unchanged in those aged 16–47. Moreover, in the MONICA study in northern Sweden [28], women’s self-rated health declined from 1990 to 2014 whereas men’s self-rated health increased. A French study showed a general decline in health-related quality of life between 1995 and 2016 in the female population [29]. Sleep problems, identified as an important stressor, also have substantial impact on health and well-being [30]. Sleep problems were included as stress factor in our mental stress question, and thus included as mental stress augmenter. In contrast, sleep problems were not named explicitly in the well-being question.

The increase of the proportion of women who experience high mental stress is also seen in other studies. Despite the fact that Sweden is an equal country, there are large differences in the number of unpaid working hours (women 26.5 h/week, men 21 h/week) [31]. Life expectancy is increasing in Sweden, but clear differences remain. Health gaps based on education are growing. Women with low level of education have only marginally increased their life expectancy, while survival rates have increased among women with high level of education [32]. The results of the present study are not entirely consistent with this.

Several possible explanations for the difference in well-being between Swedish 38- and 50-year-old women are possible. Today’s 38-year-old women are more likely to have young children, compared to previous generations. This is related to women having a higher average age at the first marriage [33]. In 1980, the average age at first marriage in Sweden was 26. In 2004, the average age at first marriage was 32 and in 2016, the average age was 34. Another possible influence is a higher median age for the first divorce, from 36 years in 1980 to 42 years in 2014 [33]. Finally, changes in BMI represent another possible explanation for the difference in well-being between 38- and 50-year-old women observed in the present study. While both 38-and 50-year-old cohorts reported changes in smoking and physical activity, only the 38-year-old cohorts had an increasing significant trend showing an increase in the prevalence of BMI ≥25, whereas in the 50-year-old cohorts prevalences were unchanged.

Middle aged women of today seem to perceive both high well-being and high mental stress irrespective of belonging to low or high SEP group. This is in contrast to 1980, when poor well-being was associated with low SEP. Significant secular trends were seen, such that low SEP as risk factor for poor well-being disappeared from 1980 to 2016. Perception of high mental stress increased between 1980 and 2016, for both 38-and 50-year-old women, irrespective of SEP. Further studies are needed to explore determinants of women’s well-being and mental stress, including studies within the context of the ongoing global pandemic.