Social Class, Social Mobility and Risk of Psychiatric Disorder - A Population-Based Longitudinal Study

<div><p>Objectives</p><p>This study explored how adult social class and social mobility between parental and own adult social class is related to psychiatric disorder.</p> <p>Material and Methods</p><p>In this prospective cohort study, over 1 million employed Swedes born in 1949-1959 were included. Information on parental class (1960) and own mid-life social class (1980 and 1990) was retrieved from the censuses and categorised as High Non-manual, Low Non-manual, High Manual, Low Manual and Self-employed. After identifying adult class, individuals were followed for psychiatric disorder by first admission of schizophrenia, alcoholism and drug dependency, affective psychosis and neurosis or personality disorder (N=24 659) from the Swedish Patient Register. We used Poisson regression analysis to estimate first admission rates of psychiatric disorder per 100 000 person-years and relative risks (RR) by adult social class (treated as a time-varying covariate). The RRs of psychiatric disorder among the Non-manual and Manual classes were also estimated by magnitude of social mobility.</p> <p>Results</p><p>The rate of psychiatric disorder was significantly higher among individuals belonging to the Low manual class as compared with the High Non-manual class. Compared to High Non-manual class, the risk for psychiatric disorder ranged from 2.07 (Low Manual class) to 1.38 (Low Non-manual class). Parental class had a minor impact on these estimates. Among the Non-manual and Manual classes, downward mobility was associated with increased risk and upward mobility with decreased risk of psychiatric disorder. In addition, downward mobility was inversely associated with the magnitude of social mobility, independent of parental class.</p> <p>Conclusions</p><p>Independently of parental social class, the risk of psychiatric disorder increases with increased downward social mobility and decreases with increased upward mobility.</p> </div

Relative risk (x-axis) of psychiatric disorder and two-sided 95% confidence intervals comparing different trajectories of social mobility (y-axis -3 to +3) versus subjects socially stable (stable between parent class to adult class; reference group).

<div><p>For each trajectory (-3, -2 ,..., +3) different relative risks presented for different parental class.</p> <p>Footnote: Trajectories start from high non-manual (HN-M) parental class, low non-manual (LN-M) parental class, high manual (HM) parental class, low manual (LM) parental class by upward (y-axis +1, +2 or +3) and downward mobility ( y-axis -3, -2, -1) with their corresponding RRs and 95% CIs. Subjects=798 660; psychiatric patients:19 533.</p></div

Rate of psychiatric disorder (cases per 100 000 subjects) versus age at diagnosis.

<div><p>Rate developments by adult social class at cohort entry. </p> <p>Footnote: Subjects=1 016 276; psychiatric patients: 24 659. Swedish born in 1949–1959.</p></div

Overview of the time-points at which information for the studied subjects and their parents has been retrieved.

<p>Overview of the time-points at which information for the studied subjects and their parents has been retrieved.</p

Incidence rates of myocardial infarction by socioeconomic position for Swedish men and women in three age groups.

<p>All models were adjusted for birth country and stratified by sex and attained age. Note 1 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105279#pone-0105279-g001" target="_blank">Figure 1:</a> The shadowed area indicates a time period for which results cannot be interpreted.</p

Incidence rates of ischemic stroke by socioeconomic position for Swedish men and women in three age groups.

<p>All models were adjusted for birth country and stratified by sex and attained age. Note 1 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105279#pone-0105279-g002" target="_blank">Figure 2:</a> The shadowed area indicates a time period for which results cannot be interpreted. Note 2 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105279#pone-0105279-g002" target="_blank">Figure 2:</a> The incidence rate of ischemic stroke is increasing until 1997 due to changing in ICD codes 9 and 10, the result until 1997 is uncertain.</p

Incidence rate ratios (IRR) with 95% confidence intervals (CI) of myocardial infarction and ischemic stroke by socioeconomic position and calendar year, and stratified by sex and attained age.

<p>Incidence rate ratios (IRR) with 95% confidence intervals (CI) of myocardial infarction and ischemic stroke by socioeconomic position and calendar year, and stratified by sex and attained age.</p

Frequencies and incidence rates of myocardial infarction and ischemic stroke by sex, attained age, birth country and socioeconomic position.

1<p>Unadjusted incidence rate per 100,000 person-years.</p>2<p>Age and sex standardized incidence rate per 100,000 person-years using the Swedish population in 2011 as standard population).</p><p>Frequencies and incidence rates of myocardial infarction and ischemic stroke by sex, attained age, birth country and socioeconomic position.</p