Screening details, relative risks and confidence intervals for included studies by study design.

NR = Not reported.A. Most studies reported mortality as incidence-based breast cancer mortality. These studies report both incidence and prevalence-based breast cancer mortality. Numbers in cells represent incidence-based mortality.B. Studies report only prevalence-based breast cancer mortality. Numbers shown reflect prevalence-based mortality numbers and RR calculations.C. For the Otto,2003 study, mammograms were 2-view in the first round and were 1-view in subsequent rounds. For the No Author, 1999 study, type of mammogram varied by screening center. Women in the screened group also received clinical breast exam during non-screened year.D. Study authors reported all mortality and population numbers by age categories. We excluded women screened ages 40–49 because of the overlap with the Hellquist paper. We then separated the data for women screened 50–69 and 70–74 in order to include in meta-analyses for each age category.E. RR and CI reported in this table are only for the comparison of Gavleborg to all of Sweden.F. RR and CI reported in this table are only for the comparison of Turku to Helsinki. The comparison of Turku to Tampere was not included because of overlap and because Tampere screened women 55–59.G. RR slightly different as RR reported in original article was adjusted for pre-trial rates, which we did not do.H. Study only reports aggregate population data. No individual cases are identified or linked from medical records or cancer registries.I. The specific year that screening began varied by county or region.J. Screening expanded to women age 70 in 2002.K. We only analyzed women in cohort 1.

NR 即未报告（Not reported）。
A. 多数研究以基于发病的乳腺癌死亡率形式报告死亡率。此类研究同时报告基于发病及基于流行的乳腺癌死亡率，单元格内数值代表基于发病的死亡率。
B. 部分研究仅报告基于流行的乳腺癌死亡率，表格中展示的数值为基于流行的死亡率数据及相对危险度（Relative Risk, RR）计算结果。
C. 在2003年Otto的研究中，首轮乳腺钼靶检查为双侧投照（2-view），后续轮次为单侧投照（1-view）；在1999年无作者署名的研究中，乳腺钼靶检查类型因筛查中心不同而存在差异。筛查组女性在非筛查年度也接受了临床乳腺检查。
D. 研究作者按年龄组别报告了所有死亡率及人口数据。由于与Hellquist的研究存在数据重叠，我们剔除了40~49岁接受筛查的女性数据；随后我们将50~69岁及70~74岁接受筛查的女性数据进行拆分，以便用于各年龄组别的荟萃分析（meta-analyses）。
E. 本表中报告的相对危险度（Relative Risk, RR）及置信区间（Confidence Interval, CI）仅针对耶夫勒（Gavleborg）与全瑞典人群的对比结果。
F. 本表中报告的相对危险度及置信区间仅针对图尔库（Turku）与赫尔辛基（Helsinki）的对比结果。由于数据重叠，且坦佩雷（Tampere）的筛查对象为55~59岁女性，因此未纳入图尔库与坦佩雷的对比数据。
G. 本次研究的相对危险度与原始文献略有差异，原因在于原始文献中的相对危险度已根据试验前的发生率进行了校正，而我们未进行此项校正。
H. 本研究仅报告汇总后的人口数据，未从医疗记录或癌症登记系统中识别或关联到个体病例信息。
I. 各郡或地区的筛查起始年份各不相同。
J. 2002年筛查范围扩大至70岁女性。
K. 我们仅对第1队列（cohort 1）的女性进行了分析。