Although healthier lifestyle choices play a part in avoiding some of the deadly diseases, researchers think the single most important factor is a positive mental attitude.
Women who maintained a positive outlook were around 70 per cent less likely to suffer from a deadly disease when they retired than a woman who was frequently pessimistic.
Researchers from the Harvard T H Chan School of Public Health made the connection between health and optimism when they analysed data from more than 70,000 women who took part in the Nurses' Health Study.
Optimism seemed to trump all the usual factors associated with good health, such as marriage and socio-economic background, and it even lessened the harmful effects of conditions such as diabetes, high blood pressure, high cholesterol levels and depression.
The good news is that optimism is a learned skill. Lead researcher Dr Eric Kim says there are several exercises we can introduce into our daily lives to help engender positive thinking. One is to imagine 'your best possible self', where you have achieved all your personal and professional goals; another is to write down three things for which you are grateful every day, and a third is to keep a log of all the little acts of kindness you do for others. Learning mindfulness meditation could also help, he says.
Genetic factors play only a small part in determining whether someone was optimistic, which suggests that it's something that can be nourished and expanded, Dr Kim added.