Background To examine the combined influence of changes in physical activity, diet, smoking and alcohol consumption on all-cause mortality.

Methods Health behaviours were assessed in 1984/1985 and 1991/1992 in 8123 adults from the UK (4666 women, median age 41.0 years). An unhealthy lifestyle score was calculated, allocating one point for smoking, fruits and vegetables <3 times a day, physical activity <2 hours a week and >14 units (women) or >21 units of alcohol (men) per week.

Results There were 2003 deaths over a median follow-up of 6.6 years (IQR 5.9–7.2) following the resurvey. The modal change in the unhealthy lifestyle score was zero, 41.8% had the same score, 35.5% decreased and 22.7% increased score between surveys. A one unit decrease in the unhealthy lifestyle score was not associated with a beneficial effect on mortality (HR 0.93; 95% CI 0.83 to 1.04). A one unit increase in the unhealthy lifestyle score increased the risk of mortality (adjusted HR 1.09; 95% CI 1.01 to 1.18).

Conclusions In this general population sample, the adoption of an unhealthy lifestyle was associated with an increased risk of mortality.