The role of psychosocial factors in explaining socio-economic differences in mobility decline in a chronically ill population: results from the GLOBE study

In chronically ill patients, mobility develops more unfavorably in persons with low socio-economic status (SES) than in their better-off counterparts. Using longitudinal data from the Dutch GLOBE study (a study of health and living conditions in Eindhoven and its surroundings), the present study examines whether psychosocial factors can explain socio-economic differences in mobility decline, independent of disease severity, co-morbidity, and health-related behavior in a chronically ill population. Data were from 1384 men and woman, aged 15–74 years, suffering from at least one of the four chronic diseases: asthma/COPD, heart disease, diabetes mellitus, and low back pain. Three indicators of SES were used: education, occupational class, and income. Change in physical mobility between 1991 and 1997 was measured with the Nottingham Health Profile (NHP). Psychosocial factors were measured extensively and included life events, long-term difficulties, coping styles, social support, and personality characteristics. Low occupational level and low income predicted an increased risk of mobility decline in comparison to people with a higher occupational level and income, even after controlling for sociodemographics, disease severity, co-morbidity, and health-related behavior. Additional adjustment for psychosocial factors hardly reduced the SES-related odds ratios of mobility decline. We conclude that psychosocial factors (and also health-related behaviors, disease severity and co-morbidity) cannot explain socio-economic differences in mobility decline in a chronically ill population. Our findings will not give us new tools for prevention and intervention strategies in order to reduce physical disability and particularly the SES differences therein.