Researchers have found that individuals with greater optimism are more likely to live longer and achieve "exceptional longevity".

"While research has identified many risk factors for diseases and premature death, we know relatively less about positive psychosocial factors that can promote healthy aging," said Lewina Lee, Assistant Professor at the Boston University.

The study, published in the journal Proceedings of the National Academy of Sciences, was based on 69,744 women and 1,429 men. Both groups completed survey measures to assess their level of optimism, as well as their overall health and health habits such as diet, smoking and alcohol use.

Women were followed for 10 years, while men were followed for 30 years.

When individuals were compared based on their initial levels of optimism, the researchers found that the most optimistic men and women demonstrated, on average, an 11 to 15 per cent longer lifespan, and had 50-70 per cent greater odds of reaching the age of 85 compared to the least optimistic groups.

The results were maintained after accounting for age, demographic factors such as educational attainment, chronic diseases, depression and also health behaviours, such as alcohol use, exercise, diet and primary care visits.

The researchers also consider that more optimistic people tend to have healthier habits, such as being more likely to engage in more exercise and less likely to smoke, which could extend lifespan.