The latest Gay Force studies are convenience samples extracted from varying source. Styles noticed can for this reason result from actual alterations in sexual habits or away from changes in the latest socio-group construction of your respondents. One method to ensure the newest comparability of one’s samples is always to shot in the event the indications that are not supposed to change-over time contained in this a given generation happen to be stable. By way of example, decades to start with intercourse claimed of the MSM of your 1980–1983 age bracket should be the exact same on 1995 questionnaire whenever he could be 31–33 yrs . trГ¤ffa unga singelkvinnor old as in the new 2004 survey whenever what their age is is 39–42. Consequently, just after controlling to have age group, zero significant effectation of the brand new questionnaire season would be to will still be. We put linear and you may logistic designs to check that it assumption to have degree level (degree in participants old ? 20), sex of earliest mate and you will years initially intercourse that have a man; survey decades had been incorporated due to the fact dummy details. Patterns was together with modified to own age in the survey when planning on taking on account this new contribution prejudice connected with decades within sort of comfort survey [38, 39]. Decades and you will age group was indeed included in the activities since persisted details after fractional polynomial conversion in the event it increased model complement .

Efficiency of this preliminary analysis showed that while the survey year had a highly significant effect (p _year Fig 1 ), and median age at first intercourse with a man was represented by age group ( Fig 2 ). Standard age-cohort representations on raw data were used for the number of male partners ( Fig 3 ) and sexual practices ( Fig 4 ).

Surveys inside the 1995–2011, respondents old 18–59. Reading: Participants old twenty-five–31 interviewed during the 1995 got became 18 for the 1986 normally along with an average many years to start with intercourse with men comparable to 17.8. Traces is removed only when new age bracket comprises of at the very least 30 participants.

Results

Surveys inside 1991–2011, respondents aged 18–59. Reading: twenty two.5% of the participants regarding 1996–1999 age group stated over ten male partners in the previous 12 months when their imply decades are 18.6 many years (we.e., after they were surveyed into the 1997). Outlines is actually removed only when the brand new age bracket contains from the the very least 29 participants.

Surveys from inside the 1985–2011, respondents aged 18–59. Reading: 61.5% of one’s respondents on 1996–1999 age bracket advertised constant anal intercourse when its mean aged was 18.six years (i.e., after they were interviewed from inside the 1997).Lines is actually taken on condition that brand new age bracket is constructed of at the minimum 30 participants.

Eventually, an effective multivariate logistic regression was conducted to examine things associated with reporting more than ten people in the previous one year out-of the brand new 1991 for the 2011 surveys. Many years and you may many years squared was basically as part of the model to adjust on the quadratic effect of many years toward created adjustable. We utilized the Wald take to to test to have relations anywhere between for each of your own confounding parameters (survey source, self-defined sexual direction, size of city of residence and number of education) and you may age (linear title) and age bracket.

Profiles off MSM throughout the studies ( Desk 1 )

The mean age of the respondents varied between 31.2 and 35.8 years from one survey to another (p Fig 1 represents the age-adjusted percentages of respondents who reported that their first sexual intercourse was with a man, by generation. It shows that younger generations had their first intercourse with a man more frequently than the older ones did: 76.0% in the 1956–1959 generation, 75.6% in the 1980–1983 generation, and 83.7% in the 2008–2011 generation (p_full = 0.0002).

Fig dos shows average years at first sexual intercourse that have a beneficial people based on year off 18 th birthday. This new median age at that event remained secure at around 18, starting with brand new 1970 age bracket. As informed me more than, young participants (old 18–24) had a reduced median many years to start with intercourse (up to 17) because of contribution bias; shortly after modifications to have age, age in the beginning sex didn’t disagree between your 1968–1971 years and people who adopted all of them (p = 0.21).