There has been a fall in the percentage of people aged under 75 reporting good general health.
Census 2022 found that the percentage of people reporting their general health status as either very good or good decreased from 87% in the last census in 2016 to 83% in 2022.
Some 52% of people aged 35 to 39 reported very good health, compared with 61% in 2016.
In contrast, there was a small increase in the proportion of people aged 75 and over who reported very good health in 2022.
Census 2022 shows the number of unpaid carers has increased by 53% since 2016 to over 299,000, with people aged between 50 and 59 most likely to be providing regular unpaid care.
Cork City and Wexford recorded the highest proportion of people with a long-lasting health condition, disability or difficulty to any extent, while Fingal and Monaghan recorded the lowest proportions.
A question on smoking tobacco products, included for the first time in an Irish census, found 13% of the population smoked either daily or occasionally, with a higher prevalence of smoking among people in their 20s and 30s, with more men than women smoking daily across all ages.
On disability, just over 1.1m people, or 22% of the population, reported experiencing at least one long-lasting condition or difficulty to any extent, with more females than males in the categories.
The census also found that just under one in three children under 15 were in childcare in 2022, with a creche the most common form of childcare, providing care to 139,899 children in April 2022.
The second most common type of childcare was provided by an unpaid relative or family member.