PMC full text: | Published online 2011 May 16. doi: 10.1186/1471-2474-12-98
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Table 1
Summary of demographic and study data in a longitudinal study of Danish children/adolescents at three time points (T1, T2 and T3).
Description of studies Time point T1 T2 T3 Number of participants: males/females 227/252 250/234 192/251 Age mean [range] 9.7 [8.7,15.5] 13.1 [12.1 - 14.4] 15.7 [14.7 - 17.1] Years since last interview [range] 3.4 [3.0 - 4.0] 2.7 [2.2 - 3.1] Period of data collection August 1997 -June 1998 March 2001 -October 2001 November 2003 -May 2004