Table 1

 Comparison of men who did (n = 1580) and did not know (n = 932) how they were fed as an infant

VariableBreast feeding status known (%)Breast feeding status unknown (%)p Value†
*The number in each category varies as some subjects had missing data. †Based on χ2 test for categorical variables and unpaired t test for birth weight.
Social class in childhood
    Non-manual1310
    Manual8790
    Number*15217710.02
Birth order
    First3126
    Second2422
    Third1514
    Fourth or more3038
    Number*1570822<0.001
Father unemployed
    No5651
    Yes4449
    Number*13325790.05
Birth place
    Caerphilly5052
    Other UK4746
    Outside UK32
    Number*15788390.2
Social class in adulthood
    Non-manual3526
    Manual6574
    Number*1541904< 0.001
Smoking history
    Never2724
    Ex smoker3028
    Current smoker4348
    Number*15749270.07
Age at baseline examination
    44 to 493628
    50 to 543134
    >55 over3338
    Number*1580932<0.001
Mean (SD)
Birth weight, kg3.65 (0.86)3.47 (0.88)0.009
Number*1079179