Socioeconomic gradient in morbidity and mortality in people with diabetes: cohort study findings from the Whitehall study and the WHO multinational study of vascular disease in diabetes
BMJ 1998; 316 doi: https://doi.org/10.1136/bmj.316.7125.100 (Published 10 January 1998) Cite this as: BMJ 1998;316:100
- Nish Chaturvedi, senior lecturer in clinical epidemiology (nish{at}public-health.ucl.ac.uk)a,
- John Jarrett, emeritus professor of clinical epidemiologya,
- Martin J Shipley, senior lecturer in medical statisticsa,
- John H Fuller, professor of clinical epidemiologya
- a EURODIAB, Department of Epidemiology and Public Health, University College London, London WC1E 6BT
- Correspondence to: Dr Chaturvedi
- Accepted 16 September 1997
Abstract
Objectives: To assess whether the inverse socioeconomic mortality gradient observed in the general population persists in diabetic people.
Design: The Whitehall cohort study and the London cohort of the WHO multinational study of vascular disease in diabetes.
Setting: London.
Subjects: 17 264 male civil servants (17 046 without diabetes, 218 with diabetes) aged 40–64 examined in 1967-9, and 300 people with diabetes aged 35–55 from London clinics examined in 1975-7. Both cohorts were followed up until January 1995.
Main outcome measures: Mortality from all causes, cardiovascular disease, and ischaemic heart disease.
Results: In both cohorts people in the lower social groups were older, had higher blood pressure, and were more likely to smoke. In the Whitehall study, the prevalence of heart disease was higher in the lowest social group compared with the highest group, by 6% among non-diabetic people (P=0.0001) and by 14% among diabetic subjects (P=0.02). In the WHO study proteinuria was more common in the lowest social group compared with the highest (27% v 15%, P=0.01), as was retinopathy (54% v 48%, P=0.5). There was a clear socioeconomic gradient in all cause mortality in both cohorts, with death rates being about twice as high in the lowest compared with the highest social groups. In the Whitehall study this gradient was similar in both diabetic and non-diabetic subjects, and it persisted for mortality from cardiovascular disease and from ischaemic heart disease. About half of the increased risk of death in the lowest social group was accounted for by blood pressure and smoking.
Conclusions: We confirm the existence of an inverse socioeconomic mortality gradient in diabetic people and suggest that this is largely due to conventional cardiovascular risk factors.
Key messages
People in lower social classes tend to have higher mortality than those in higher classes, but a Finnish study found no such socioeconomic gradient in mortality among diabetic people
In response to this research we examined mortality in two large studies with 20 year follow up of 17 264 Whitehall civil servants (218 with diabetes) and 300 patients attending diabetes clinics in London
Mortality was twice as high in diabetic people in the lowest socioeconomic groups as in those in the highest groups
This difference was largely due to higher rates of smoking and high blood pressure in the lowest social groups, while blood glucose concentration had little impact on the relation
These results emphasise the importance of improving conventional cardiovascular risk factors and reducing social inequality for reducing mortality in diabetic people
Footnotes
- Accepted 16 September 1997