Trends in type 2 diabetes incidence and mortality in Scotland between 2004 and 2013

The relative contribution of increasing incidence and declining mortality to increasing prevalence of type 2 diabetes in Scotland is unclear. Trends in incidence and mortality rates are described for type 2 diabetes in Scotland between 2004 and 2013 by age, sex and socioeconomic deprivation.

Data for incident and prevalent cases of type 2 diabetes were obtained from the Scottish national diabetes register with number of deaths identified from linkage to mortality records. Population size and death data for Scotland by age, sex and socioeconomic deprivation were obtained from National Records of Scotland. Age- and sex-specific incidence and mortality rates stratified by year and deciles of socioeconomic status were calculated using Poisson models.

There were 180,290 incident cases of type 2 diabetes in Scotland between 2004 and 2013. Overall, incidence of type 2 diabetes remained stable over time and was 4.88 (95% CI 4.84, 4.90) and 3.33 (3.28, 3.32) per 1000 in men and women, respectively. However, incidence increased among young men, remained stable in young women, and declined in older men and women. Incidence rates declined in all socioeconomic groups but increased after 2008 in the most deprived groups. Standardised mortality ratios associated with diabetes, adjusted for age and socioeconomic group, were 1.38 (1.36, 1.41) in men and 1.49 (1.45, 1.52) in women, and remained constant over time.

Incidence of type 2 diabetes has stabilised in recent years suggesting that increasing prevalence may be primarily attributed to declining mortality. Prevention of type 2 diabetes remains important, particularly among socioeconomically deprived populations.