Table 5.
Background survey information for the Finnish sexual survey [24], the Polymod study [23] and the STEP study used to estimate the measures of diagonality for age-based mixing of sexual, casual and drug-sharing contacts
| Survey | Contact type | Survey year(s) | Sample size | Definition of a contact | Diagonality (95% CI) |
|---|---|---|---|---|---|
| Finnish sexual survey (Finland, simple random probability sample) | Sexual | 1991–1992 | 1079 contacts among 1392 respondents | A ‘current, steady, sexual partner’ (i.e. a marital partner or one with whom respondent was cohabitating at the time of survey)a | 50.2% (44.2–57.6%) |
| Polymod (eight European countries; various recruiting methods including random digit dialling, population registers, etc.) | Casual/social | 2005–2006 | 97 904contacts among 7290 respondents | Any individuals with whom respondent came into contact, including skin-to-skin contact (e.g. a kiss or handshake) or a two-way conversation in the physical presence of another person. Weekly diaries were maintained for 17 months | 22.8% |
| STEP (Baltimore, USA, convenience sample of PWID) | Equipment sharing in illicit drug use | 2005–2006 | 2651 contacts among 647 respondents | Any individual with whom the respondent shared a cooker or needle when injecting drugs in the past 6 months. Named individuals had to have been known to respondent for at least 1 month | 28.0% (29.5–26.5%) |
a
Although the survey explored questions of multiple sexual partnerships, ages of sexual partners were only available for those described as ‘steady’ partners.
CI, confidence interval.