Similar decline in mortality rate of older persons with and without type 2 diabetes between 1993 and 2004 the Icelandic population-based Reykjavik and AGES-Reykjavik cohort studies

• Published in: BMC public health 2013-01, Vol.13 (1), p.36-36, Article 36
• Main Authors: Olafsdottir, Elin, Aspelund, Thor, Sigurdsson, Gunnar, Benediktsson, Rafn, Thorsson, Bolli, Harris, Tamara B, Launer, Lenore J, Eiriksdottir, Gudny, Gudnason, Vilmundur
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Cardiovascular disease; Cardiovascular Diseases - mortality; Cause of Death - trends; Chronic diseases; Cohort Studies; Diabetes Mellitus, Type 2 - mortality; Female; Heart attacks; Humans; Iceland; Iceland - epidemiology; Life expectancy; Male; Medical research; Medicine, Experimental; Mortality; Prognosis; Risk factors; Studies; United Kingdom; United States; Womens health
• ISSN: 1471-2458; 1471-2458
• DOI: 10.1186/1471-2458-13-36

A decline in mortality rates due to cardiovascular diseases and all-cause mortality has led to increased life expectancy in the Western world in recent decades. At the same time, the prevalence of type 2 diabetes, a disease associated with a twofold excess risk of cardiovascular disease and mortality, has been increasing. The objective of this study was to estimate the secular trend of cardiovascular and all-cause mortality rates in two population-based cohorts of older persons, with and without type 2 diabetes, examined 11 years apart. 1506 participants (42% men) from the population-based Reykjavik Study, examined during 1991-1996 (median 1993), mean age 75.0 years, and 4814 participants (43% men) from the AGES-Reykjavik Study, examined during 2002-2006 (median 2004), mean age 77.2 years, age range in both cohorts 70-87 years. The main outcome measures were age-specific mortality rates due to cardiovascular disease and all causes, over two consecutive 5.7- and 5.3-year follow-up periods. A 32% decline in cardiovascular mortality rate and a 19% decline in all-cause mortality rate were observed between 1993 and 2004. The decline was greater in those with type 2 diabetes, as illustrated by the decline in the adjusted hazard ratio of cardiovascular mortality in individuals with diabetes compared to those without diabetes, from 1.88 (95% CI 1.24-2.85) in 1993 to 1.46 (95% CI 1.11-1.91) in 2004. We also observed a concurrent decrease in major cardiovascular risk factors in both those with and without diabetes. A higher proportion of persons with diabetes received glucose-lowering, hypertensive and lipid-lowering medication in 2004. A decline in cardiovascular and all-cause mortality rates was observed in older persons during the period 1993-2004, in both those with and without type 2 diabetes. This decline may be partly explained by improvements in cardiovascular risk factors and medical treatment over the period studied. However, type 2 diabetes still persists as an independent risk factor for cardiovascular mortality.