Socioeconomic inequalities in health have been widely analysed at the national and cross-national level but there is less evidence at the urban level, even though inequalities in cities may be as important as those in countries.1 Large urban areas are a setting for global/local dynamics, from climate change to job delocalisation, migration and housing bubbles potentially affecting health inequalities. The aim of this study was to provide evidence of trends in socioeconomic inequalities in self-assessed health and mental health during the last 16 years in the urban area of Barcelona (Spain).

A common feature of socioeconomic inequalities in self-assessed health, at both the cross-national and national level, is the persistence of inequalities across European countries or small oscillations without trend.2 Recent trends in socioeconomic health inequalities have inevitably dealt with the effects of the 2008 economic crisis, and inequalities since then have seemed unchanged. For instance, one study using national surveys reported that absolute inequalities by education and occupation in self-assessed health were mostly constant across 17 European countries in 1990 and 2010, and while relative inequalities increased, almost no country consistently experienced a significant decline in either absolute or relative inequalities.3 Another study analysing health inequalities by education level across 27 European countries observed no discernible short-term impact of the 2008 crisis at the population level.4 Similarly, one study using the European Union of Income and Living Conditions (EU-SILC) panel from 2005 to 2011 did no find differences before and after the economic crisis among low educated and unemployed.5 Several national experiences also show the persistence of socioeconomic health inequalities. For instance, in Japan, relative and absolute socioeconomic inequalities by household income in self-assessed health narrowed or remained stable between 1986 and 2007, despite the economic stagnation during the 90s and adverse social changes.6 Similarly, inequalities by education level and income also appear to persist in Germany during the period 2003-2012 after the recession of 2008.7 In England, self-perceived health (and mental health) remained stable from 1996 to 2009, with no evidence of widening socioeconomic inequalities.8 However, another study using the EU-SILC panel data but for the recovery years from 2011 to 2013 found steeper declines in self-assessed health among unemployed and single mothers and no different by education level.9 These results suggest that the effects of the economic crisis may disproportionally affect specific social groups and with larger effects with elapsed time since the start of the economic crisis. In Spain, the evidence for trends in self-assessed health inequalities is not clear cut.10 One study using the National Health Survey (NHS) for year 2006 and 2011 reported increasing inequalities in self-assessed health by education level.11 A worse trend in self-assessed health among unemployed was also reported using the Living Conditions Survey for years 2007 and 2011.12 A finding that was not confirmed applying matching technics to data from NHS for the years 2006 and 2011.13 Interestingly, a study including four waves 2005, 2008, 2011, 2014 of the Bank of Spain's Survey of Household Finances found worse self-assessed health trends among family types characterized with a low job intensity.14 Again, the results point that the economic crisis may have exacerbated inequalities through weakening the labour market position of specific social groups for which economic recovery fades away.

Unlike the persistent inequalities reported in self-assessed health, mental health can be more sensitive to situations of short-term employment and material deprivation. There is an extensive literature on mental health trends since the economic recession. Systematic reviews have concluded a worsening of the mental health trends since the economic crisis.15 As expected, a higher risk of psychosocial problems has been found across European countries among unemployed persons, those with a lower educational level and those living in urban areas.16 However, these recent increases in mental health problems can only partially be explained by trends in unemployment and wages. It has been alleged that the austerity measures have contributed to the widening in mental health inequalities.17 For instance, in England, relative inequalities in mental health reduced following the recession, between 2008 and 2010, but increased significantly more between the recovery years 2009 and 2013 and seemed to widen thereafter.18 In Spain, since the 2008 economic crisis, mental health has also clearly deteriorated.19 The increase in inequalities is largely due to a worse trend among those in the lowest socioeconomic position. At national level, using two waves of the national health survey for years 2006 and 2012, increasing inequalities have been found by social class among men and long-term unemployed.13,20,21 At regional level, it has been found larger adverse effects among those with lower education level in Andalusia for years 2007 and 2012,22 and using four waves of the Basque Health Survey from 1997 to 2013, an increase in relative inequalities by social class among men.23

This study contributes to the existing literature by extending the period of analysis and showing its evolution at local level. The objective was to analyse socioeconomic inequalities by occupational social class in the self-assessed health and mental health of the Barcelona population by using data from a quinquennial survey from 2001 to 2016.

Demographic and socioeconomic changes during the study period are shown in Table 1. Comparing the first and final year, there was an upward trend in the share of the population older than 75 years, unmarried people, those in the highest occupational class, unemployed persons and a large increase in the share of immigrant population. The trends for health outcomes were favourable for poor self-assessed health (decreasing by 2.6% for men and 4.5% for women), but were unfavourable for poor mental health (increasing by 6.3% for men and 2.5% for women).

Age-standardised prevalences with confidence intervals in poor self-assessed health and mental health by occupational class, sex and years are shown in Table 2. The broad picture is that in the post-crisis period (2016) inequality levels recovered from the pre-crisis periods, with 2011 —during the economic crisis— being the year when inequalities reduced due to a simultaneous increase in adverse health status in non-manual classes and a reduction of poor health status in the manual classes. For men, the gap in poor self-assessed health by class squeezes in 2011 (6.0%) but widens again in 2016 (14.3%) below the pre-crisis gap (20.1% for 2001 and 20.7% for 2006). The gap in poor mental health remains fairly stable from 2001 to 2011 (between 6.2% and 8.0%) but reaches a maximum in 2016 (20.4%). Among women, the gap in poor self-assessed health by class follows a similar pattern of that of men, squeezing in 2011 (6.7%) but widening again in 2016 (23.4%) below to the pre-crisis gap (29.2% for 2001 and 28.6% for 2006). The gap in mental health also reaches a minimum in 2011 (1.6%) but widens again in 2016 (16.6%) below to pre-crisis levels in 2006 (19.1%). For men and women, the increases in 2016, specially for poor mental health, are driven by the worsening among manual classes.

Tables 3 and 4 show the relative risk by occupational class, the relative index of inequality and the absolute difference of poor health outcomes and year for men and women. The first shows a socioeconomic gradient for most years, with the population in the lower occupational classes having a higher risk of experiencing poor self-perceived and mental health than the higher ones. Both the RII and the SII for self-assessed health followed this V-shape trend of vanishing inequalities during the economic crisis and for mental health even widened again in 2016. For poor self-assessed health, the RII (95% confidence interval) decreased among men, from 3.42 (2.61-4.47) in 2001 to a non-significant value in 2011, but increased to 2.83 (1.81-4.42) in 2016. The same occurred for poor mental health, from 2.04 (1.37-3.03) in 2001 to a non-significant value in 2011, and rose again to 4.02 (2.43-6.64) in 2016. For women, the RII for poor self-assessed health decreased from 3.16 (2.55-3.91) in 2001 to 1.66 (1.14-2.40) in 2011 and rose again to 3.92 (2.67-5.76) in 2016. For poor mental health, the RII decreased from 1.83 (1.39-2.41) in 2001 to a non-significant value in 2011 and rose again to 3.55 (2.31-5.47) in 2016. For men and women, absolute inequalities in self-assessed health also followed a V-shape and widened for mental health in 2016. When we adjusted for employment situation, inequalities for self-assessed health and mental health were reduced for both men and women but a large share of inequality remains with variability across the years.

The use of data from the Barcelona city quinquennial health surveys from 2001 to 2016 revealed persistent absolute and relative inequalities by occupational social class in self-assessed health and mental health outcomes for men and women across years except during the economic crisis in 2011, which showed a drop. Absolute inequalities in mental health widened in the post-crisis period in 2016 in both men and women to values higher than pre-crisis values. Adjustment for employment status reduced absolute inequalities in both sexes but a large share of inequality remains.

Our results suggest that the recurrent inequality was due to faster increases in poor self-assessed health and mental health among persons with lower socioeconomic position after the economic crisis compared to those with a more advantaged socioeconomic position, for whom it declined. This result contrasts with recent findings of a slowdown in declines in poor self-assessed health among people with both low and high socioeconomic position in the countries worst hit by the economic crisis, leaving inequalities unchanged.4 An examination of the Spanish case confirmed previous studies that the economic crisis could have affected more intensely those in lower socioeconomic classes.10,14 The increase in health inequalities recorded in Barcelona in 2016 may be related with labour reforms enacted after the economic crisis. The worsening of the work environment has been pointed as a potential mechanism to the increasing inequalities in health.12,23 The Spanish labour reform of 2012 made layoff cheaper, weakened coverage of collective agreements and increased job insecurity.27 Our analysis that includes a longer term, probably captures better the lasting effect of the relentless crisis than previous research, especially for mental health. Absolute and relative inequalities in mental health for men and women in 2016 widened compared to figures for previous years. These findings are close to the pattern followed by England from 1991 to 2014, when inequalities in mental widened after the recession and during the austerity measures.18 The adverse working conditions, job insecurity, higher unemployment rates and poor prospects for younger people disproportionately affected persons with lower socioeconomic position.28 Indeed, this hypothesis is partially confirmed by the reduction in absolute inequalities in mental health after adjustment for employment situation. Our results differ from some previous research that finds increasing inequalities for men only.20,21,23 In Barcelona, temporary work, part-time work and other precarious working arrangements spread across the work force but affected women more than men.28 However, absolute inequalities in 2016, after adjustment for employment, still remained above mean trends, and consequently a large share in inequalities remains unexplained, with employment situation only partly explaining recent increases in mental health problems.22 Even though it has been alleged that the health system in Spain has managed to avoid irreversible deterioration,29 the magnitude of the social crisis depends on the welfare response to the economic crisis.30 In the case of Barcelona, the trend towards a reduction in health inequalities seems to have been offset by the lasting effects of the economic crisis and the austerity response, reversing any reduction in inequalities and making them persistent or even widening.

An unexpected finding was that, during the economic crisis in 2011, this population showed the largest reduction in inequalities. It has been suggested that the economic crisis offered some social groups the possibility of acquiring healthier habits: more hours of sleep, more physical exercise, less demanding work, more home-made cooking, and more time for leisure.31 Some scholars have stressed the differential effects of the economic crisis on specific social groups, depending on what the dominant mechanism is, a coping response or a stressful one.32 Nonetheless, our results also show an increase in adverse health outcomes during the economic crisis for people with high socioeconomic position. It also has been pointed that the populations with better objective health indicators report worse perceived health, due to an adverse social context, known as the “status inconsistency effect‿, and on the contrary “survivor employees‿ in an adverse work environment may overestimate their living conditions, known as the “other's unemployment effect‿12,32. The lack of a worsening of an adverse health effect amidst the economic crisis may also be due to a delayed effect. It has been emphasised that inequalities have stronger effects on self-assessed health in follow-up analyses with the incorporation of lag effects.33

A strength of our study is that it used robust at the city level and covered a wide time span. It is recommended to report both RII and SII, both measures have the advantage of including the information available from all socioeconomic position. However, changes in the composition of those groups can lead to bias in the interpretation of disparities.34 Our inequality estimates can be conservative because, with increasing precariousness, occupational class may not fully capture emerging sources of inequality such as those engaged in highly temporary jobs, or other adverse working conditions. In this regard, the GHQ is also known to have lower sensitivity to more disadvantaged groups so that underlying inequalities can be underestimated.35

In summary, the lasting effects of the 2008 economic crisis and the austerity programmes imposed since then may have contributed to the persistence of socioeconomic inequalities in self-assessed health and the widening of those for mental health.

Miguel ÿngel Negrín Hernández.

The corresponding author on behalf of the other authors guarantee the accuracy, transparency and honesty of the data and information contained in the study, that no relevant information has been omitted and that all discrepancies between authors have been adequately resolved and described.

X. Bartoll-Roca designed the study and carried it out. L. Palència and M. Gotsens provided methodological support. C. Borrell contributed in writing and discussing the results. All the authors have contributed corrections and improvements in the writing and final presentation of the study.

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