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Table 2 Proportion (%) of women with mixed/dense mammographic density by screening age, period, and birth cohort

From: Mammographic density in birth cohorts of Danish women: a longitudinal study

Copenhagen Period 1991–93 (n=29991) Period 1993–95 (n=25920) Period 1995–97 (n=24981) Period 1997–99 (n=25269) Period 1999–2001 (n=24910) Total
Age (years)       
50-51, n=7818 64 (63–65) 67 (66–68) 72 (71–73) 76 (75–77) 81 (81–82) 72 (72–73)
52-53, n=16808 56 (55–57) 62 (61–63) 68 (67–68) 73 (72–73) 80 (79–80) 68 (68–69)
54-55, n=14962 54 (53–55) 54 (53–55) 61 (60–61) 66 (66–67) 75 (74–75) 63 (62–63)
56-57, n=13546 50 (49–50) 53 (52–54) 54 (53–55) 61 (60–62) 68 (67–69) 57 (57–58)
58-59, n=12455 48 (47–49) 50 (49–51) 52 (51–53) 54 (53–55) 63 (62–64) 54 (53–54)
60-61, n=12007 45 (44–46) 47 (46–48) 50 (49–51) 53 (52–54) 56 (55–57) 50 (49–50)
62-63, n=11758 43 (43–44) 44 (43–45) 47 (46–48) 48 (47–49) 55 (52–54) 47 (46–47)
64-65, n=11627 43 (42–44) 42 (41–43) 43 (42–44) 47 (46–48) 51 (50–52) 45 (44–45)
66-67, n=11886 42 (41–42) 42 (41–43) 43 (42–44) 46 (45–47) 49 (48–50) 44 (43–44)
68-69, n=12009 42 (41–43) 42 (41–43) 43 (42–44) 43 (42–44) 48 (47–49) 43 (43–44)
70-71, n=6194 41 (40–42) 42 (41–43) 43 (41–44) 45 (44–47) 46 (44–47) 43 (42–44)
Total 47 (47–48) 49 (49–50) 53 (53–54) 58 (57–58) 64 (64–64)  
Funen 1 Period 1994– 95 (n=39059) Period 1996– 97 (n=42767) Period 1998– 99 (n=43564) Period 2000– 01 (n=45275)   Total
Age (years)       
50-51, n=23122 73 (72–74) 75 (74–76) 80 (79–81) 84 (83–85)   78 (77–78)
52-53, n=22277 68 (67–70) 65 (64–66) 74 (73–75) 79 (78–80)   72 (71–73)
54-55, n=20506 64 (63–66) 61 (60–63) 68 (66–69) 76 (74–77)   68 (67–68)
56-57, n=18539 60 (59–62) 58 (56–59) 64 (62–65) 71 (69–72)   64 (63–64)
58-59, n=16776 58 (56–59) 56 (54–47) 62 (61–64) 68 (67–69)   61 (60–62)
60-61, n=15664 55 (53–56) 53 (52–55) 59 (57–60) 67 (65–68)   59 (58–59)
62-63, n=14734 50 (49–52) 50 (49–52) 57 (55–59) 64 (63–66)   56 (55–57)
64-65, n=13820 49 (47–51) 45 (44–47) 54 (53–56) 62 (60–64)   53 (52–54)
66-67, n=13065 49 (47–51) 47 (45–49) 49 (47–51) 60 (58–62)   51 (50–52)
68-69, n=12162 46 (45–48) 45 (44–47) 50 (48–52) 55 (53–57)   49 (48–50)
Total 59 (58–59) 58 (57–58) 64 (63–64) 70 (70–71)   
  1. Mammography screening program of Copenhagen (1991–2001) and Funen (1994–2001), Denmark.
  2. 1The second round of Funen was to some extent affected by film problems during the year 1996 which could result in some inconsistency when comparing screening round 2 with the other screening rounds.