The protocol was registered with the PROSPERO database (CRD42014007569) [ 23] on 03 March 14 and the registration was updated on 18 December 2014.
The registration system is updated weekly with information on all births, deaths, or emigrations of the population.
The Civil Registration System is updated daily, with information on vital status (dead or alive), and date of death.
The Danish Civil Registration System is updated daily, and maintains records on date of birth, death, and current residence of all Danish citizens.
This registration system is updated daily and contains complete information since 1968 on migration, vital status, and the exact date of death (when relevant) for all Danish citizens [ 24].
The Danish Civil Registration System which is updated daily, tracks changes in vital status and migration for the entire Danish population [ 8].
12 The data used in this study are part of the M&H Co, including: (1) The Swedish Total Population Register, which covers the entire population registration in Sweden and is updated on a daily basis.
The Civil Registration System (CRS), 11 which is updated daily, was used for personal data, including date of birth and death, place of residence and marital status.
We identified all-cause death using the Danish Civil Registration System (established on April 2 , 1968, which is updated daily and records all changes in vital status, date of death, and migration [ 14].
The Danish Civil Registration System, which was implemented in 1968, is updated daily.
