Social inequalities in mental health in Norway: possible explanatory factors

BACKGROUND It is well known that there is a social gradient in mental health, the prevalence of mental disorders stepwise increasing by lower social status. The reason for this, however, is not clear, and the purpose of the present study was to explore possible mediating factors between social status and mental health. METHODS The study has a cross-sectional design, and was based on a nationwide survey in Oslo, Norway, counting 12 310 people in the age of 30-60 years. Immigrants from non-western countries were excluded. Socio-demographic data were gathered from existing registers, whereas data on health, psychosocial variables and life style were gathered by structured interview. As indicator of mental health was used a 10-items version of Hopkins Symptom Checklist, measuring psychological distress. Measures of general self-efficacy and sense of powerlessness was used as indicators of control of own life situation. RESULTS A strong social gradient in mental health was found, the prevalence of psychological distress increasing by decreasing social status. Psychosocial factors, including self-efficacy, sense of powerlessness, control of work, social support and negative life events, in particular economic problems, as well as life style factors (physical exercise, BMI, smoking) and somatic health, likewise showed a social gradient, all risk factors increasing by decreasing social status. When adjusting for the risk factors in multivariate statistical analyses, the social gradient in mental health was eliminated. Low self-efficacy and sense of powerlessness emerged as important explanatory factors, alongside with poor social support, economic problems, smoking and somatic disorder. CONCLUSION Both individual characteristics, supposedly linked to the personality, like low self-efficacy, and factors related to the actual life situation, like economic problems and a feeling of powerlessness, contribute to the social gradient in mental health, and both aspects should be addressed in preventive work.