Interpreting self reported limiting long term illness

Objective:To examine the association between self reported limiting long term illness and other dimensions of self reported health. Design:Stratified random sample of general population. Setting:Lothian region, Scotland, in 1993. Subjects:6212 men and women aged 16 and over. Main outcome measures:Limiting long term illness was assessed by the same question as used in the 1991 United Kingdom census. The short form 36 health survey was used to assess other dimensions of health. Results:Rates of limiting long term illness were much higher than reported in the census. Scores on general and physical health scales had strong associations with limiting long term illness, but after adjustment for these associations psychosocial health measures had little influence on limiting long term illness. Being at the lower rather than the upper quartile on the physical functioning scale more than doubled the odds of having limiting long term illness. Reported prevalence of many common illnesses was between two and three times higher among those with limiting long term illness. Conclusions:A positive response to the question used by the census to define limiting long term illness was strongly associated with physical limitations on activity and less strongly influenced by scores on scales of mental and social wellbeing. Socioeconomic effects on limiting long term illness seem largely mediated through measures of general health and physical limitations on health.