Optimistic women are less likely to develop deadly diseases, according to a paper published in the American Journal of Epidemiology.
In the study of over 120,000 women, those who self-identified as optimistic were ‘significantly’ less likely to get fatal heart disease, cancer and stroke in old age.
Study participants (retired and working US nurses between the ages of 58 and 83) were asked to rate their optimism on a scale of zero to 24. They were monitored over a period of eight years, during which there were 4,566 deaths.
The reduced death risk associated with optimism remained after other factors, such as socioeconomic background and disease history, were taken into account.
The researchers believe that optimism may have a biological effect as well as a psychological one, citing a twin study that found that up to 25 per cent of optimism might be genetic.
This was a prospective cohort study of 121,700 nurses, of whom 90 per cent have been followed up. The cohort group has generated a number of significant research papers across the specialities.
A validated questionnaire was used to assess optimism in subjects and causes of death were meticulously ascertained.
A considerable number of confounding factors were taken into consideration so as to make the necessary statistical adjustments, such as healthy behaviours, chronic physical disease, mental health and socioeconomic factors.
Bearing in mind that the majority of the women were white, married professionals, the applicability of the results to the general population may be questionable.
The results showed that greater optimism in general was associated with decreased mortality from cardiovascular disease (50 per cent), lung disease (52 per cent), infection (71 per cent) and total cancer deaths (26 per cent).
There are various possible explanations for these results. More optimism is linked with less stress, which by itself may be associated with extremely deleterious biochemical changes in the body which contribute to worse outcomes from a multitude of diseases.