Fig 1. Restricted cubic spline graph of the association between cumulative years as a baggage handler and meniscal lesions.

Copenhagen Airport Cohort, 1994–2012. Cox regression model adjusted for status as a baggage handler (yes/no), age, educational level, calendar year, pre-employment knee injury, use of baggage lifter and use of extendable belt loader. Dotted lines represent 95% confidence intervals.