People who have an upbeat outlook on life have a lower risk of cardiovascular conditions and premature death, a review of studies has found.
The review comes after research published last month suggested optimists had a greater chance of living to a ripe old age than those with a less sunny disposition.
The research, which looked at evidence from 15 previously published studies, cannot prove that being optimistic is the driver of better heart health and a lower risk of death.
However, the authors note the associations remained even after various other factors that might explain them were considered including education level, whether participants had depression and the amount of exercise they did. They also say there are plausible mechanisms by which optimism might have an effect.
The team say the results are interesting since optimism is largely influenced by non-genetic factors, meaning it might be possible to shift people’s mindsets and, potentially, improve their health outcomes – although that idea is still being researched.
Prof Alan Rozanski of the Icahn School of Medicine at Mount Sinai, first author of the research, said boosting optimism meant more than simply telling people to “think positively”.
“We have multiple ways to help them including [developing skills for] problem solving, developing the muscle of positive thinking through interventions like gratitude, and using cognitive behavioural therapy,” he said.
Published in the journal Jama Network Open, the research examines results from 15 studies encompassing a total of almost 230,000 participants. Ten of the studies explored a link between optimism and the risk of cardiovascular events, such as heart attack or death from heart disease, while nine looked at the risk of death. All were published between 2001 and 2017, and followed participants for anywhere between two and 40 years.
Rozanski noted that all of the studies took the presence of other health conditions into account. The vast majority of studies showed a link between an upbeat outlook and a lower risk of cardiovascular events and the risk of death during their study period – although the size of the association differed.
When the results of different studies were taken together, the team found that compared with the least optimistic participants, the most optimistic had a 35% lower risk of cardiovascular events and a 14% lower risk of early death.
Links remained even when the team looked particularly at the impact of depression, exercise, education, or the length of time participants were followed – although in some cases the size of the link was affected. What’s more, 12 of the 15 studies found a dose response – in other words, the more optimistic you are, the lower the risk of either outcome.
Rozanski said there were a variety of possible mechanisms for the links, including that more optimistic people tended to lead healthier lives, such as having better diets, being proactive and anticipating problems, while there was evidence that they also had lower blood pressure and less inflammation than more pessimistic people. Another factor, he said, could be that optimistic people were better at problem-solving and coping with adversity.
However, the new research has limitations – not least that some of the studies measured optimism in different ways, and followed up with participants of different ages and over different periods of time, while almost all were conducted in the US or Europe.
However, the team say their results are backed up by other studies showing links between optimism and a lower risk of other health problems, including heart failure and respiratory disease infection.
Rozanski said optimism was only one of many factors linked to health outcomes, meaning problems could not be prevented simply by positive thinking, and there was much more to explore.
“I think it would be valid to look at other mindsets – gratitude, sense of life purpose – or, on the negative side, what does a strong sense of regret or resentment do to people?” he said. “We in medicine need to start to look at the importance of mindsets and its intimate relationship to health.”