Table 1.

RRs for sibship size

Cancer siteSibship size
1*
2
3
≥4
CasesRRCasesRR (95% CI)CasesRR (95% CI)CasesRR (95% CI)PtrendTotal
Leukemias1,0411.002,5941.04 (0.97-1.12)2,1721.14 (1.04-1.25)1,8431.13 (1.00-1.27)0.0167,650
    ALL2091.008881.09 (0.94-1.28)8101.29 (1.08-1.55)5061.29 (1.02-1.63)0.0032,413
    Chronic lymphocytic leukemia2561.003520.97 (0.83-1.13)2661.08 (0.88-1.33)2831.01 (0.76-1.35)0.8421,157
    Acute myeloid leukemia3541.008571.07 (0.94-1.21)6711.08 (0.92-1.27)6261.08 (0.87-1.33)0.4562,508
    Acute monocytic leukemia91.00291.48 (1.00-2.19)242.02 (1.24-3.29)212.51 (1.37-4.60)0.00283
    Other leukemias711.002381.17 (0.89-1.71)2241.24 (0.89-1.71)2331.43 (0.96-2.14)0.115766
    Polycythemia vera881.001591.17 (0.93-1.47)1141.16 (0.84-1.60)1061.01 (0.66-1.56)0.757467
    Myelofibrosis541.00710.81 (0.56-1.18)630.92 (0.56-1.52)680.91 (0.47-1.77)0.713256
Hodgkin's lymphoma4121.001,1241.17 (0.94-1.45)8781.09 (0.93-1.29)7011.17 (0.94-1.45)0.1193,115
NHL1,2471.002,2870.96 (0.89-1.04)1,6560.96 (0.87-1.06)1,8171.06 (0.92-1.21)0.6657,007
    Diffuse large B cell981.001850.98 (0.70-1.36)1190.94 (0.61-1.46)1391.06 (0.60-1.88)0.950541
    Diffuse lymphoblastic81.00311.16 (0.59-2.27)332.02 (0.91-4.51)171.10 (0.37-3.28)0.28989
    Follicular1731.002670.82 (0.68-1.00)1870.76 (0.58-0.98)2370.85 (0.61-1.20)0.207864
    B cell, NOS1331.002351.07 (0.82-1.39)1450.94 (0.65-1.35)1790.93 (0.58-1.51)0.765692
    NHL, NOS1421.002761.03 (0.87-1.24)1960.94 (0.75-1.19)2090.90 (0.66-1.23)0.489823
    T cell541.001261.03 (0.67-1.59)760.76 (0.44-1.33)890.80 (0.39-1.67)0.380345
    Others1391.002831.13 (0.92-1.38)2061.24 (0.95-1.62)1871.33 (0.93-1.90)0.097815
Multiple myeloma2801.004961.24 (1.10-1.39)3161.19 (1.01-1.40)4001.34 (1.08-1.66)0.0061,492
  • NOTE: RR and 95% CI are adjusted for age, sex, number of older and younger siblings, residential area, birth cohort, parity, age at first birth, family history of cancer, and socioeconomic index.

  • * Reference category.

  • The total number of NHL subtypes does not add up to the total number of NHLs because the histologic information was available starting from 1993.