Socioeconomic gradients in cardiorespiratory disease and diabetes in the 1960s: Baseline findings from the GPO study

Summary 

Objectives

To describe the socioeconomic distribution of risk factors for cardiorespiratory disease and diabetes in employed women and men in the late 1960s.

Study design and methods

Cross-sectional data were collected from 3345 General Post Office (GPO) employees in London, via a questionnaire and clinical examination, between October 1966 and April 1967.

Results

Our occupational grade classification conformed to expected patterns of greater car ownership and gardening among higher-grade women and men, and greater height in higher-grade men (highest–lowest grade 175.0–170.7cm, P<0.001). A strong inverse grade gradient in bronchitis (2.1–9.4%, P<0.001) and a strong positive gradient in FEV₁ (3.10–2.58l, P<0.001) were observed in men, although smoking was less consistently associated with grade. There was no consistent inverse association between grade and any cardiovascular risk factor in either sex, but strong inverse gradients in prevalence of impaired glucose tolerance (IGT) (5.1–18.2%, P<0.001) and 2-h glucose (4.14–4.25mmol/l, P<0.001) in non-diabetic men. Using car ownership as an alternative measure of socioeconomic position, findings in men were replicated for respiratory measures, IGT and 2-h glucose prevalence. Inverse gradients were additionally observed for blood pressure, cholesterol and electrocardiogram abnormalities.

Conclusions

The GPO study confirms existing evidence of socioeconomic gradients in respiratory risk factors and provides new evidence of gradients in risk factors for diabetes in men. Although there was no conclusive evidence of an occupational gradient in any cardiovascular risk factor, car ownership was a good indicator of lower risk in men. No socioeconomic gradients in cardiorespiratory or diabetic risk factors were observed in women.

Keywords: Cardiorespiratory disease, Diabetes, Risk factors, Socioeconomic distribution, 1960s