Background Relationships between deprivation and elevated mortality risk have been demonstrated in a very large number of studies. Links between diabetes and increased risk of death are also well established. However, few studies have directly compared these two sets of associations simultaneously in a single population. The objective of this study was to quantify separately the relationships of deprivation and of type 2 diabetes mellitus (T2DM) to life expectancy in Scotland during the period 2011–2013.

Methods Data for all people in Scotland living with T2DM in 2011–2013 were used to estimate sex- and age-specific life expectancy (LE) in the age range 40–89 years, stratified by an area-based measure of socioeconomic status (SES). Corresponding LE values were generated for the general Scottish population (after excluding those with T2DM). Differences in LE were calculated (a) between those in the most deprived and most affluent quintiles of the population without T2DM (estimating the effect of deprivation on LE); and (b) between those in the most affluent quintile of the population with and without T2DM (estimating the effect of T2DM on LE).

Results For men, differences in LE (in years) associated with deprivation ranged from −8.6 (95% confidence interval [CI]: −8.9, −8.3) at ages 40–44 to −1.1 (−1.3, −0.9) at ages 85–89; negative values indicate lower LE in the most deprived quintile. Differences associated with T2DM in men extended from −3.9 (−4.5, −3.3) at ages 45–49 to −0.9 (−1.2, −0.6) at ages 85–89; negative values represent lower LE in those with T2DM. For women, deprivation-related differences in LE ranged from −6.0 (−6.2, −5.8) at ages 40–44 to −0.6 (−0.7, −0.5) at ages 85–89. T2DM-related differences in LE for women ranged from −5.7 (−7.0, −4.4) at ages 40–44 to −0.8 (−1.1, −0.5) at ages 85–89. Deprivation-related differences in men were materially larger at most ages than corresponding T2DM-related differences. For women, differences in LE associated with the two factors were generally much closer in value.

Conclusion In men, SES (specifically, the contrast between the most- and least-deprived population quintiles) is associated with greater disparities in the expectation of life than type 2 diabetes, reinforcing the need for continuing effort to confront the massive and pervasive challenge of social inequalities in health. For women, the respective effects on LE of these two conceptual ‘insults’ – deprivation and T2DM – are broadly similar. Further work to identify explanations for the observed between-sex difference is merited.