The objectives of the study were to discover the main determinants for the prevalence of varicose veins in a general population, and to assess the possibilities for prevention of this common surgical disease. Varicose veins were evaluated in three defined cohorts of 3284 men and 3590 women aged 40, 50, and 60 years by using a validated questionnaire. The response rate was 75% among men and 86% among women, and varicose veins were determined by self-assessment. Increasing age, female sex, childbirths, standing posture at work, higher weight or height, and positive family history were significantly associated with varicose veins in a univariate analysis. These factors were further taken into a multivariate logistic regression analysis, and female gender (adjusted odds ratio, OR 2.2), increasing age (OR 2.2-2.8), a reported positive family history for varicose veins (OR 4.9), increasing number of births (OR 1.2-2.8), standing posture at work (OR 1.6), and higher weight (OR 1.2) and height (OR 1.4) were found to independent and significant risk indicators of varicose veins. Increasing age, positive family history of varicose veins, and child-births in women were the most important factors in terms of population etiologic fractions. Familial predisposition and pregnancy-related factors bear important associations with varicose veins. Thus prevention of varicose veins appears to be difficult. Varicose veins are nonlethal and, therefore, higher age is related to higher prevalence.