Social inequalities in prevalence of diagnosed and undiagnosed diabetes and impaired glucose regulation in participants in the Health Surveys for England series

OBJECTIVES: To ascertain the extent of socioeconomic and health condition inequalities in people with diagnosed and undiagnosed diabetes and impaired glucose regulation (IGR) in random samples of the general population in England, as earlier diagnosis of diabetes and treatment of people with IGR can reduce adverse sequelae of diabetes. Various screening instruments were compared to identify IGR, in addition to undiagnosed diabetes. DESIGN: 5, annual cross-sectional health examination surveys; data adjusted for complex survey design. SETTING: Random selection of private homes across England, new sample annually 2009–2013. PARTICIPANTS: 5, nationally representative random samples of the general, free-living population: ≥1 adult interviewed in 24 254 of 36 889 eligible addresses selected. 18 399 adults had a valid glycated haemoglobin (HbA1c) measurement and answered the diabetes questions. MAIN OUTCOME MEASURES: Diagnosed diabetes, undiagnosed diabetes (HbA1c ≥48 mmol/mol), IGR (HbA1c 42–47 mmol/mol). RESULTS: Overall, 11% of the population had IGR, 2% undiagnosed and 6% diagnosed diabetes. Age-standardised prevalence was highest among Asian (19% (95% CI 16% to 23%), 3% (2% to 5%) and 12% (9% to 16%) respectively) and black participants (17% (13% to 21%), 2% (1% to 4%) and 14% (9% to 20%) respectively). These were also higher among people with lower income, less education, lower occupational class and greater deprivation. Education (OR 1.49 (95% CI 1.27 to 1.74) for no qualifications vs degree or higher) and income (1.35 (1.12 to 1.62) for lowest vs highest income quintile) remained significantly associated with IGR or undiagnosed diabetes on multivariate regression. The greatest odds of IGR or undiagnosed diabetes were with increasing age over 34 years (eg, OR 18.69 (11.53 to 30.28) aged 65–74 vs 16–24). Other significant associations were ethnic group (Asian (3.91 (3.02 to 5.05)), African-American (2.34 (1.62 to 3.38)) or ‘other’ (2.04 (1.07 to 3.88)) vs Caucasian); sex (OR 1.32(1.19 to 1.46) for men vs women); body mass index (3.54 (2.52 to 4.96) for morbidly obese vs not overweight); and waist circumference (2.00 (1.67 to 2.38) for very high vs low). CONCLUSIONS: Social inequalities in hyperglycaemia exist, additional to well-known demographic and anthropometric risk factors for diabetes and IGR.