PURPOSE: We aimed to estimate trends of dementia incidence and to compute and compare all-cause mortality among people living with and without dementia, in a whole regionalpopulation, from 2013 to 2023. METHODS: Our retrospective population-wide cohort study included 7,030,374 people aged 50 years and older from regional administrative data, living in Lombardy, the most populous Italian region. We computed annual age-standardised dementia incidence estimated rates and age-standardised all-cause mortality estimated rates among people living with and without dementia, both overall and stratified by age and sex. RESULTS: Over the last decade, age-standardised dementia incidence estimated rates have decreased by 52,8% for women and 53,1% for males. In contrast, age-standardised all-cause mortality estimated rates among people living with dementia grew by 14,0% for women and 21,8% for males. Conversely, during the pandemic, there was a higher excess in mortality estimated rates in the female population living with dementia compared to the male, up to 60% in older groups aged 80 or older. In the male population without dementia compared to the female, the higher excess was up to 50% in age groups of 70-74 and 75-79. CONCLUSIONS: Our study reported a reduction in dementia incidence and increase in all-cause mortality of people living with dementia over the last decade, indicating that dementia prevalence is declining. Moreover, previously under-investigated gender disparities in mortality estimated rates emerged across different age groups during the pandemic.