Table 2.

RRs for number of older siblings

Cancer siteNo. older siblings
None*
1 or 2
3 or 4
≥5
CasesRRCasesRR (95% CI)CasesRR (95% CI)CasesRR (95% CI)PtrendTotal
Leukemias3,9411.003,2380.97 (0.91-1.03)4100.95 (0.83-1.10)610.81 (0.62-1.07)0.1807,650
    ALL1,1111.001,1490.93 (0.84-1.02)1530.86 (0.68-1.08)0.1122,413
    Chronic lymphocytic leukemia7031.004041.06 (0.91-1.24)501.03 (0.70-1.52)0.5401,157
    Acute myeloid leukemia1,2781.001,0701.03 (0.94-1.14)1601.02 (0.81-1.29)0.5862,508
    Acute monocytic leukemia441.00340.62 (0.46-0.85)50.35 (0.17-0.74)0.00183
    Other leukemias3751.003240.93 (0.76-1.13)671.05 (0.68-1.62)0.710766
    Polycythemia vera2821.001640.88 (0.68-1.13)210.76 (0.40-1.44)0.285467
    Myelofibrosis1481.00931.03 (0.74-1.43)151.03 (0.49-2.17)0.870256
Hodgkin's lymphoma1,5261.001,3980.91 (0.82-1.00)1700.69 (0.54-0.89)210.41 (0.25-0.69)0.0033,115
NHL3,7331.002,8311.05 (0.98-1.12)3680.95 (0.81-1.12)751.01 (0.77-1.34)0.4647,007
    Diffuse large B cell2781.002191.05 (0.78-1.41)441.14 (0.59-2.22)0.699541
    Diffuse lymphoblastic381.00430.87 (0.50-1.49)81.96 (0.62-6.25)0.86289
    Follicular4641.003461.13 (0.95-1.34)540.99 (0.66-1.48)0.367864
    B cell, NOS3961.002471.02 (0.80-1.30)491.63 (0.94-2.81)0.381692
    NHL, NOS4441.003331.01 (0.86-1.17)460.71 (0.49-1.02)0.464823
    T cell1691.001511.26 (0.88-1.82)251.26 (0.54-2.92)0.262345
    Others4551.003180.87 (0.73-1.05)420.72 (0.46-1.12)0.103815
Multiple myeloma8831.005240.95 (0.86-1.06)751.04 (0.80-1.35)100.77 (0.46-1.30)0.4711,492
  • NOTE: RR and 95% CI are adjusted for age, sex, total number of siblings, number of 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.