In 2021, the diseases of the circulatory system continued to be the cause of the highest number of deaths in Portugal (32,452), despite the 6.2% decrease in relation to the previous year. In relative terms, those deaths represented 25.9% of all deaths, 5.9 pp less than in the previous year and 4.0 pp less than in 2019. Of all deaths due to diseases of the circulatory system, it stood out those caused by strokes (9,613 deaths), despite a decrease of 16.0% compared to the previous year. There were also fewer deaths from ischemic heart disease (6,683 deaths) and from acute myocardial infarction (3,977 deaths), in both cases 2.4% less than in 2020.

The COVID-19 disease was the third leading cause of death in the year, with 12,986 deaths, representing 10.4% of all deaths in the country. This result considers the number of deaths in which the underlying cause of death, i.e., the disease that initiated the chain of pathological events that led to death, was the COVID-19. More than 80% of deaths caused by COVID-19 (81.3%) occurred in the first quarter of 2021, with 10,559 deaths recorded. Deaths due to COVID-19 that occurred in August (3.1%) and December (4.4%) also stood out. The mortality rate from the COVID-19 disease was 124.5 deaths per 100,000 residents in Portugal, higher for men (139.3 per 100,000 men) than for women (111.0 per 100,000 women). The mean age at death was 80.5 years, higher for women (82.5 years) than for men (78.8 years).

Diseases of the respiratory system, which, as defined by the World Health Organization for the ICD-10 classification, do not include the disease COVID-19, caused 10,273 deaths in 2021, 8.8% less than in 2020, and represented 8.2% of the total mortality in the country (less 0.9 pp than in 2020 and less 2.7 pp than in 2019). Of all deaths due to diseases of the respiratory system, deaths caused by pneumonia stood out, with 3,765 deaths, which represented 3.0% of the mortality that occurred in 2021 (3.5% in 2020 and 4.2% in 2019), despite the reduction of 13. 6% compared to the previous year.

In 2021, deaths from malignant neoplasms of the trachea, bronchi and lungs increased by 1.9%: 4,318 deaths in 2020 and 4,400 deaths in 2021. Deaths from malignant neoplasms of the colon, rectum and anus decreased in 2021 (from 3 810 deaths in 2020 to 3,609 deaths in 2021), representing 2.9% of mortality in 2021 (3.1% in 2020 and 3.4% in 2019).