Social inequalities in morbidity from diabetes mellitus in public primary care clinics in Trinidad and Tobago

Associations between socio-economic status and non-communicable diseases in middle income countries have received little study. We conducted an interview survey to evaluate the associations of morbidity with social conditions among people attending government primary care health centres with diabetes mellitus in Trinidad. Data collected included morbidity from hyperglycaemia, foot problems, visual problems and cardiovascular disease, as well as social and demographic variables. Of 622 subjects, 35% were aged >=65 years, 54% were Indo-Trinidadian, 13% had no schooling, only 11% were in full-time employment, and 33% had no piped drinking water supply in the home. Prevalent symptoms included itching, reported by 215 (35%), nocturia in 315 (51%), burning or numbness in the feet in 350 (56%), and difficulty with eyesight in 363 (58%). A morbidity summary score was used as dependent variable in regression analyses. Comparing those with no schooling with those with secondary education, the mean difference in morbidity score was 1.77 (95% CI 1.15-2.39), attenuated to 0.71 (0.06-1.37) after adjusting for age, gender, ethnic group and diabetes duration. The equivalent differences for those with no piped water supply in the house, compared with those with, were 0.53 (0.17-0.88) and 0.57 (0.24-0.89). For the unemployed, compared with those in full-time jobs, at ages 15-59 years the differences were 0.85 (0.14-1.56) and 0.58 (-0.11-1.27). We conclude that morbidity in persons with diabetes is associated with indicators of lower socio-economic status and that this association is partly explained by confounding with older age, female gender, longer duration of diabetes and Indo-Trinidadian ethnic group. A negative association between socio-economic status and morbidity from diabetes contributes to a justification for investment of public health resources in the control of diabetes and other non-communicable diseases.