BackgroundMeniscal lesions are among the most common injuries of the knee, yet limited epidemiologic data is available on their risk factors. We investigated the association of lifestyle factors and physical strenuousness of work on knee injuries with a focus on meniscal lesions.MethodsWe examined a nationally representative sample of persons aged 30 to 59 years, who participated in a comprehensive health examination (the Mini-Finland Health Survey). Subjects without any injury or osteoarthritis in the knee joint at baseline (n = 4713) were subsequently followed via the National Hospital Discharge Register up to 30 years.ResultsDuring the follow-up, 338 knee injuries were identified of which 224 were meniscal lesions. Obesity and regular leisure time physical exercise were associated with an increased risk of first hospitalization due to meniscal lesions (hazard ratio (HR) 1.62 and 95% confidence interval (CI) 1.06–2.48 and 1.53, 95% CI 1.05–2.23, respectively). The types of sports predicting the highest risk of meniscal lesions were ballgames, gymnastics and jogging. Physical strenuousness of work did not predict meniscal lesion. The hazard of other knee injury was increased among those reporting irregular or regular physical exercise at baseline (HR 1.64, 95% CI 1.03–2.64 and 1.88 CI 1.05–2.36, respectively). Smoking or alcohol intake were not associated with knee injuries.ConclusionsBetter safety measures in high-risk sports and weight control would likely improve the prevention of meniscal lesions in populations.