Table 1 Effects of time, age and marital status on having one or more casual partners in the past 12 months by gender, 1997–2006
Explanatory variableSample size*Adjusted odds ratio (95% CI)†p Value†
Women
Age (years)
    13–197616 (4.0)1 (reference)
    20–243188 (3.9)1.92 (1.51 to 2.45)<0.001
    25–344818 (2.7)1.54 (1.20 to 1.97)0.001
    35–443602 (2.5)1.23 (0.95 to 1.60)0.112
    45+6033 (0.8)0.24 (0.18 to 0.34)<0.001
Survey year
    19971677 (1.4)1 (reference)
    19992222 (2.5)2.01 (1.17 to 3.44)0.012
    20003398 (3.4)2.98 (1.78 to 4.97)<0.001
    20013599 (3.6)3.01 (1.82 to 5.00)<0.001
    20033535 (2.5)2.17 (1.29 to 3.64)0.004
    20043805 (3.7)3.25 (1.95 to 5.42)<0.001
    20053562 (2.6)2.25 (1.33 to 3.81)0.002
    20063464 (1.4)1.27 (0.73 to 2.23)0.393
Marital status
    Unmarried13505 (4.1)1 (reference)
    Married11085 (1.1)0.19 (0.15 to 0.24)<0.001
Men
Age (years)
    13–198055 (8.2)1 (reference)
    20–242241 (25.8)4.65 (4.03 to 5.37)<0.001
    25–343412 (20.4)4.66 (3.97 to 5.48)<0.001
    35–442514 (13.3)2.99 (2.45 to 3.64)<0.001
    45+4943 (4.0)0.74 (0.60 to 0.92)0.006
Survey year
    19971573 (11.6)1 (reference)
    19992026 (11.1)1.03 (0.81 to 1.30)0.818
    20002857 (12.4)1.23 (0.99 to 1.52)0.065
    20013139 (12.6)1.25 (1.01 to 1.54)0.041
    20032959 (11.6)1.19 (0.96 to 1.48)0.117
    20043105 (12.7)1.35 (1.10 to 1.68)0.005
    20052774 (10.7)1.13 (0.90 to 1.41)0.284
    20062735 (10.2)1.06 (0.85 to 1.33)0.585
Marital status
    Unmarried12579 (12.7)1 (reference)
    Married8031 (9.4)0.47 (0.41 to 0.54)<0.001

  • *Values in parentheses are the percentage with ⩾1 casual partners.

  • †Adjusted odds ratio adjusts for the factors in the models other than the one in consideration (four categorical age variables, seven year variables and one categorical variable for marital status).

  • ‡Logistic regression Wald test with Huber correction.