Table 2

Factors associated with inconsistent condom use in 2387 steady partnerships among 1705 heterosexuals attending the sexually transmitted infections outpatient clinic, Amsterdam, 2010

OR (95% CI)p ValueaOR (95% CI)p Value
Individual participant characteristics
Gender0.940
 Male1
 Female1.01 (0.78 to 1.31)
Ethnicity0.290
 Dutch1
 Surinamese/Antillean1.14 (0.72 to 1.81)
 Other0.76 (0.51 to 1.12)
Interaction between ethnicity and gender0.012
 Dutch males1
 Surinamese/Antillean males2.27 (1.07 to 4.82)
 Other males2.19 (1.12 to 4.29)
 Dutch females1.35 (0.94 to 1.94)
 Surinamese/Antillean females1.15 (0.56 to 2.36)
 Other females0.72 (0.40 to 1.29)
Age in years*0.5300.370
 201.30 (0.91 to 1.84)1.41 (0.94 to 2.12)
 251.17 (0.94 to 1.45)1.14 (0.90 to 1.44)
 3011
 350.93 (0.77 to 1.13)0.95 (0.77 to 1.19)
 400.94 (0.72 to 1.23)1.01 (0.75 to 1.37)
Education0.002<0.001
 High11
 Low1.57 (1.17 to 2.09)1.96 (1.38 to 2.78)
No. of partners in the year preceding study participation*0.5400.640
 11.001
 20.95 (0.56 to 1.60)1.28 (0.73 to 2.25)
 40.79 (0.48 to 1.31)1.01 (0.58 to 1.76)
 80.72 (0.43 to 1.20)0.95 (0.53 to 1.68)
Characteristics of the partnership
Age difference in years*,‡0.0070.061
 −101.47 (0.89 to 4.45)1.47 (0.84 to 2.57)
 −51.01 (0.70 to 1.46)0.99 (0.68 to 1.45)
 01
 51.00 (0.72 to 1.38)1.15 (0.79 to 1.69)
 100.80 (0.54 to 1.19)0.96 (0.60 to 1.54)
Ethnic mixing0.0050.012
 Discordant11
 Concordant1.45 (1.12 to 1.89)1.46 (1.09 to 1.95)
Duration of a partnership in days*,§<0.001<0.001
 111
 (1 to 30)1.94 (1.30 to 2.92)2.20 (1.45 to 3.36)
 (1 to 60)2.36 (1.60 to 3.46)2.35 (1.56 to 3.53)
 (210 to 270)4.20 (2.79 to 6.30)3.20 (2.04 to 5.02)
Number of sex acts within a partnership in the preceding year<0.001<0.001
 1–411
 5–191.31 (0.95 to 1.80)1.02 (0.72 to 1.44)
 20–391.93 (1.35 to 2.77)1.37 (0.93 to 2.01)
 ≥404.88 (3.36 to 7.09)2.70 (1.76 to 4.15)
Anal sex2.57 (1.70 to 3.90)<0.0011.67 (1.09 to 2.57)0.019
Sex-related drug use¶1.83 (1.42 to 2.35)<0.0011.71 (1.30 to 2.26)<0.001
Partnership is ongoing at the time of inclusion1.21 (0.94 to 1.56)0.1401.04 (0.79 to 1.37)0.800
Concurrency of partnership**0.0150.550
 Definitely non-concurrent11
 Unknown1.73 (0.98 to 3.07)1.30 (0.81 to 2.08)
 Definitely concurrent1.43 (1.10 to 1.85)1.03 (0.75 to 1.40)
  • Missing data in duration, number of sex acts, anal sex, recreational drug use, ongoing partnership and concurrency of partnership were imputed.

  • *Continuous variables age in years, number of partners in the preceding 6 months, age difference in years and duration in days are modelled as restricted cubic splines with nodes on the 2.5th, 25th, 50th, 75th and 97.5th centiles; example ORs are given.

  • ‡Age of the partner subtracted from age of the participant.

  • §Only the month and year of first and last sexual contact were known, causing uncertainty in duration of the partnership.

  • ¶Recreational use of XTC (3,4-methyleendioxymethamfetamine), GHB (γ-hydroxybutyric acid), amphetamines, cocaine, poppers or sildefanil prior to or during sex.

  • **Only the month and year of first and last sexual contact of partnerships were known. For partnerships with an unknown concurrency status, concurrency could not be determined accurately.

  • aOR, adjusted OR.