People who adopt four healthy behaviors – not smoking; taking exercise; moderate alcohol intake; and eating five servings of fruit and vegetables a day – live on average an additional fourteen years of life compared with people who adopt none of these behaviors, according to a new study.

Rather than focusing on how an individual factor is related to health, the study calculates the combined impact of these four simply-defined forms of behavior. The results suggest that several small changes in lifestyle could have a marked impact on the health of populations.

There is overwhelming evidence showing that lifestyles such as smoking, diet and physical activity influence health and longevity but there is little information about their combined impact. Furthermore the huge amount of information provided by these studies and the varying definitions of a health behavior that these studies use can often make them confusing for public health professionals and for the general public. For example: small amounts of alcohol appear to be related to lower risk of cardiovascular disease health but what is the overall impact on longevity "

In order to examine the combined impact of changes in lifestyle, Kay-Tee Khaw and colleagues from the University of Cambridge and the Medical Research Council used a health behavior score that is easy to understand in order to assess the participants in the study (who were from Norfolk, United Kingdom). Between 1993 and 1997, 20,000 men and women between the ages of 45 and 79, none of whom had known cancer or heart or circulatory disease, completed a questionnaire that resulted in a score between 0 and 4.

A point was awarded for each of the following: not currently smoking; not being physically inactive (physical inactivity was defined as having a sedentary job and not doing any recreational exercise); a moderate alcohol intake of 1-14 units a week (a unit is half a pint of beer or a glass of wine); and a blood vitamin C level consistent with eating five servings of fruit or vegetables a day. Deaths among the participants were recorded unti l 2006.

After factoring in age, the results showed that over an average period of eleven years people with a score of 0 -- i.e. those who did not undertake any of these healthy forms of behavior -- were four times more likely to have died than those who had scored 4 in the questionnaire. Furthermore, the researchers calculate that a person who has a health score of 0 has the same riskof dying as someone 14 years older who had scored 4 in the questionnaire (i.e. someone engaging in all four healthy forms of behavior). This was independent of social class and body mass index. The study forms part of the European Prospective Investigation into Cancer and Nutrition (EPIC), conducted across ten European countries, the largest study of diet and health ever undertaken.

As a related editorial discusses, individuals in isolation often cannot make the lifestyle changes they want and a set of complex processes affect how research is translated into effective public health policy.

The results of this study need to be confirmed in other populations and an analysis of how the combined health behaviors affect quality of life is also needed. Nevertheless the results of the study strongly suggest that these four achievable lifestyle changes could have a marked improvement on the health of middle-aged and older people, which is particularly important given the ageing population in the UK and other European countries.

For more information on the Public Library of Science, visit www.plos.org.