Statistics
Basic epidemiological data are given using median and range. Time to first registration in all main groups and subgroups was analysed using stratified Cox regression, where each Marfan syndrome woman and her matched controls constituting one stratum. For the overall analyses, time at risk started at birth of the Marfan syndrome woman, and ended at the date of relevant registration, date of death, end of study, or emigration, whichever came first. Time at risk before diagnosisstarted at birth of the Marfan syndrome woman and ended at the date of relevant registration, date of the Marfan diagnosis, or emigration, whichever came first. Time at risk after diagnosis started at date of diagnosis and ended at the date of relevant registration, end of study, date of death or emigration, whichever came first. Stata 15.1 for Windows (StataCorp LP, College Station, TX, USA) was used for all calculations.