Over half of deaths in women from chronic diseases such as cancer and heart disease could be avoided if they never smoke, keep their weight in check, take exercise and eat a healthy diet low in red meat and trans-fats, according to a study published on bmj.com today.

It is well known that diet, lack of physical activity, being overweight, alcohol consumption and smoking increase the risk of disease including cancer and diabetes, but little research has examined combinations of lifestyle factors in younger populations and women.

Dr Rob van Dam and his team from the Harvard School of Public Health and Brigham and Women's Hospital, recruited nearly 80 000 women aged 34 to 59 years in 1980 who were part of the Nurses' Health Study in the US. They analysed the data of over 1.5 million person-years follow up over a 24 year period.

Participants completed detailed follow-up questionnaires every two years about their diet, frequency of physical activity, alcohol intake, weight, how much they smoked, and disease history. Deaths were confirmed by next of kin and the National Death Index.

Over the follow-up period the authors documented 8 882 deaths including 1 790 from heart disease and 4 527 from cancer.

The authors estimated that 28% of these deaths could have been avoided if women had never smoked and that 55% could have been avoided if women had combined never smoking, regular physical activity, a healthy diet and maintaining a healthy weight. Alcohol intake did not substantially change this estimate, although heavy alcohol consumption is linked to an increased risk of dying from cancer.

Smoking was found to be the biggest cause of premature death but all the other factors also contributed.

Interestingly, women with light-to-moderate alcohol consumption (up to 1 drink a day) were less likely to die from cardiovascular diseases than alcohol abstainers.

The authors believe the results of this research indicate that more needs to be done to eradicate smoking and to encourage individuals to take regular exercise and eat healthily.

They conclude that "even modest differences in lifestyle can have a substantial impact on reducing mortality rates".