Aim

To determine to what extent cardiovascular risk factor burden in midlife and late-life is related to dementia risk in individuals with type 2 diabetes, and to estimate age-specific population attributable fractions for individual and combined risk factors.

Methods

Data were used from 191,124 individuals with type 2 diabetes in midlife (age 50-65 years at baseline) and 196,220 individuals with type 2 diabetes in late-life (age 66-80 years at baseline) registered in the Swedish National Diabetes Register between 1996 and 2014. Relations of the number of cardiovascular risk factors (elevated blood pressure, elevated LDL cholesterol, poor glycemic control, overweight/obesity, smoking, albuminuria, and low physical activity) with incident dementia were estimated using Cox regression adjusted for confounders. Population attributable fractions were estimated for individual and combined risk factors.

Results

During a median follow-up of 11 years (IQR: 8-14) in midlife and 9 years (IQR: 6-12) in late-life, 4,570 and 18,308 dementia cases were identified, respectively. Higher number of cardiovascular risk factors was related to higher all-cause dementia risk in both age groups. Compared with 0-1 risk factors, hazard ratios for 6-7 risk factors were 2.14 (95% CI: 1.73-2.64) in midlife and 1.39 (95% CI: 1.24-1.56) in late-life. The population attributable fraction for all risk factors combined was 17.3% (95% CI: 12.6-22.0) in midlife and 11.3% (95% CI: 8.3-14.2) in late-life. Poor glycemic control and low physical activity were the largest contributors in both midlife and late-life.

Conclusion

Higher number of cardiovascular risk factors was related to higher dementia risk in type 2 diabetes, particularly when risk factors were assessed in midlife. A substantial proportion of dementia cases was attributable to cardiovascular risk factors, suggesting that cardiovascular risk factor management is a potential strategy to reduce dementia risk in this population.