Background: Data on the impact of the many dietary and lifestyle factors on the prevalence of hypertension in Western societies are lacking. This study quantified the contributions of body weight, physical inactivity and dietary factors to the prevalence of hypertension in Finland, Italy, the Netherlands, United Kingdom (UK) and USA.

Methods: Distributions of blood pressure (BP) and risk factors in Western populations were obtained from nationwide surveys. The effect of risk factors on BP was assessed by meta-regression analysis of randomized trials, published between 1966 and March 2001. Population attributable risk percentages (PAR%) for hypertension (i.e. systolic BP > or =140 mmHg) were computed for all risk factors in the five countries.

Results: Being overweight made the largest contribution to hypertension, with PAR% between 11% (Italy) and 25% (USA). PAR% were 5-13% for physical inactivity, 9-17% for high sodium intake, 4-17% for low potassium intake and 4-8% for low magnesium intake. The impact of alcohol was small (2-3%) in all populations. PAR% varied among populations for inadequate intake of calcium (2-8%), magnesium (4-8%), coffee (0-9%) and fish fatty acids (3-16%).

Conclusions: Diet and lifestyle have a substantial impact on hypertension in Western societies, with being overweight, physical inactivity, high sodium intake and low potassium intake being the main contributors. The relative significance of different risk factors varies among populations, which is important for preventative strategies.