There is little information on the sexual health and behaviour of young people in New Zealand (NZ). Indications from national statistics on prevalence of sexually transmitted infections and incidence of terminations are that furtherattention is required. In 2009, NZ had an estimated national chlamydia prevalence of 803 per 100,000 people, higher than in previous years and 3-4 times higher than in Australia and the UK.1NZ has high termination of pregnancy (TOP) rates compared with most OECD countries. In 2008, there were 19.7 terminations per 1000 women aged 15-44 per year compared to 19.6 in the USA, 21.3 in Sweden, and 8.7 in the Netherlands and 7.3 in Germany.2 High levels of TOP may reflect good provision of abortion services, poor availability of contraceptive services, or greater sexual activity at younger ages.3The only national survey of sexual behaviour in the general NZ population was the NZ Partner Relations Survey in 1991.4 Birth cohort studies from Dunedin and Christchurch collected some sexual health and behaviour data as the cohorts reached early adulthood 15 and 20 years ago, respectively.5,6The Dunedin cohort study of individuals born in 1972/3 found that the median age of first intercourse was 17 in women and 16 in men in the late 1980s.5 The Christchurch 1977 birth cohort reported on risk behaviours. About 32% of those aged 20-21 reported unprotected sex in the past year, and that those aged 18-21 had an average of 5.5 sexual partners during that timeframe.7University students are a large, relatively easy to reach subgroup who may serve as a sentinel population for young people more generally, notwithstanding some obvious differences. There is no contemporary information regarding the sexual health outcomes and experiences of tertiary students in NZ, but some recent information is available on sexual and other risk behaviour in younger adolescents.The Youth Health Survey of a nationally representative sample of secondary students in NZ, completed in 2001,8 showed that by age 17, 50% of students had ever had sex, 15% of sexually active students didn't use or only sometimes used condoms and/or contraception, and 63% used a condom last time they had sex. In the 2007 iteration, the authors reported no substantial change in behaviour since 2001.9Motivation for a study of sexual health, risks, and experiences amongst tertiary students comes from both this lack of information on sexual health and increasing concern about the potential impact of high levels of risky drinking. A 2005 survey found that NZ university students frequently attributed unsafe, unhappy, and unwanted sexual experiences to drinking.With reference to the preceding four weeks, 5% of women and 8% of men reported unsafe sex, 3% of women and 4% of men had sex they were not happy about at the time, and 8% of women and 9% of men had a sexual experience they later regretted that they attributed to their drinking.Unwanted sexual advances due to another person's drinking negatively affected 21% of women and 12% of men, and 0.5% of both genders reported sexual assault in those four weeks.10 This suggests adverse sexual experiences associated with drinking are fairly common on university campuses, and that the sexual health of university students is worthy of attention.The aims of this study are to better understand the sexual health, risk behaviour, and experiences of the NZ university student population by investigating age of sexual debut, number of partners, choice of partners, condom use, and occurrence of unintended pregnancies and terminations.Methods Design—Cross-sectional data were collected as part of the 2009 Tertiary Student Health Survey, using a confidential online computerised questionnaire. A detailed description of the methods for the previous iterations of this survey has been published11 and is summarised here. Participants—All 8 NZ universities were invited to participate and students from 8 campuses of 6 universities were eventually included. Enrolment lists provided by institutions were used as a sampling frame, from which random samples of full-time, intramural Māori and non-Māori students aged 17-24 years were invited by both letter and email, timed to arrive the same day, to visit a secure website and complete a questionnaire. Overall, 5770 randomly selected students were invited to participate in the 2009 survey. Measures—Information was sought from study participants on their sexual behaviour and experiences through written questions with categorical responses in drop-down menus. The first question in the sexual health section of the questionnaire was: "Have you ever had sexual intercourse?" Those answering "yes" were presented with the rest of the questions. Age at first sex: "How old were you when you first had sexual intercourse?" [<14, 14, 15, 16, 17, 18,19+] Number of partners ever: "How many people have you had sexual intercourse with in your life?" [0,1,2,3,4,5,6,7,8,9,10,10-20, >20 ] Number of partners in the last 12 months: "How many people have you had sexual intercourse with in the last 12 months?" [0,1,2,3,4,5,6,7,8,9,10, 10-20, >20] Last sexual intercourse: "Did you use a condom last time you had sex?" [yes, no] "Had you been drinking alcohol the last time you had sex?" [no, yes, a little, yes a lot] "Thinking about the last time you had sex, which best describes you and your partner..." [we had just met for the first time; we had met recently; we had known each other for a while but didn't have a steady relationship; we had a steady relationship at the time; we were living together or engaged or married] Unintended pregnancies: "Have you ever become pregnant unintentionally?" (women only) "Have you ever got someone pregnant unintentionally" (men only) [no, once, twice, more than twice] Terminations: "Did this result in a termination of pregnancy (abortion)?" (Those reporting unintended pregnancies only) [no, once, twice, more than twice, don't know] Sexual attraction: "What best describes who you feel attracted to?" [opposite sex only, opposite sex mainly, both sexes equally, same sex mainly, same sex only, no attraction] Analysis—Analyses were conducted using survey procedures in Stata version 11 software12 and weighting was used to account for the oversampling of Māori students. Bivariate analyses used chi2 tests, comparisons between groups used two-sided Student's t-tests, and p values < 0.05 were considered statistically significant. Ethical approval—The study was approved by the New Zealand Multi-region Ethics Committee (MEC/05/01/013). Results Demographics—Of the 5770 students invited to participate, 2922 (50.6%) completed the survey while a further 226 (3.9%) began but did not complete the survey. Participants had a median age of 20 and women were over-represented (61% respondents female vs. 39% male), while the university students invited were 57% female and 43% male. Most students lived in close proximity to other students with 71% living in a residential college or sharing a flat/house. Sixty-nine percent of both women and men reported having had sexual intercourse. The characteristics of the study population are described in Table 1. Table 1. Characteristics of the study population, weighted for sampling design Variables Total (n=2922) % Men (n=1140) % Women (n=1782) % Age group 17-19 years 20-21 years 22-24 years 25-26 years 46 37 17 <1 46 35 19 <1 46 39 15 <1 Ethnicity 1 NZ European NZ Māori Chinese Pacific Islands Other 75 29 6 3 9 69 25 6 3 9 80 32 6 3 9 Residence type Share a flat/house Hall of Residence Live with parent/guardian Live in own home/renting Board Other 51 20 23 3 2 1 51 19 25 3 2 1 51 20 22 3 2 1 Ever had sex Yes No Prefer not to answer 69 26 5 69 25 7 69 26 5 1Categories of ethnicity are not mutually exclusive Sexual behaviours—Of students who reported having had sex, the median age at sexual debut was 17 overall (16 for women, 17 for men) and 21% of respondents reported that they had sex before they were 16 years old (24% of women, 16% of men). The distribution of lifetime number of sexual partners was right-skewed, and the median for both women and men was three partners. For the number of sexual partners in the last 12 months the median was just one partner although the distribution shows that about 25% of university students had three or more partners during this time. The majority of students (66%) reported that the person they last had sex with was someone with whom they were in a "steady relationship" or were "living together, engaged, or married". However, 3% of women and 11% of men reported that they had "just met" the person they last had sex with. Only about half of the respondents (54%) reported using a condom the last time they had sex (men 58%, women 51%). There was a trend of decreasing condom use with increasing age (Chi-squared p<0.0001), and women were less likely to use condoms than men (Student's t-test p<0.001). Overall, 32% of respondents reported that they had been drinking the last time they had sex (men 38%, women 29%). Prevalence rates of reported sexual behaviour and risks are presented in Table 2. Table 2. Prevalence of sexual behaviours in participants who had ever had sex, weighted for sampling design Variables Total (n=2017) % Men (%) (n=783) % Women (n=1234) % Age at first sexual intercourse (years) <14 14 15 16 17 18 ≥19 Median 1 5 15 23 24 21 11 17 years 2 4 10 21 29 22 13 17 years 1 5 18 24 22 20 11 16 years Number of sex partners ever 1 2 3 4 5 6-9 10-20 >20 Median 27 16 11 11 9 13 10 3 3 27 15 13 12 8 13 9 3 3 26 17 10 10 9 16 10 2 3 Number of sexual partners in last 12 months 0 1 2 3 4 5 6-9 10-20 >20 Median 5 57 18 8 5 3 1 3 0.3 1 7 54 20 8 6 3 2 0.4 0.4 1 4 59 17 8 5 4 3 1 0.1 1 Last sexual partner Just met for the first time Met recently Known, no steady relationship In a steady relationship Living together/engaged/married 5 8 20 52 14 9 12 22 47 10 3 6 19 55 17 Condom use at last sex Yes No Prefer not to answer 54 43 3 58 39 3 51 46 3 Drinking alcohol at last sex Not at all A little Quite a lot 68 18 14 62 22 16 71 16 13 There was an association between use of a condom at last sex, and both partner choice and number of sexual partners, shown in Table 3. Use of a condom at last sex declined both as number of sexual partners increased (p=0.042) and as partner choice became more stable (p<0.0001). Table 3. Reported condom use at last sex, by reported number of sexual partners in the last 12 months and by last sexual partner, weighted for sampling design Variables Condom used at last sex? Yes (%) No (%) Number of sexual partners in last 12 months (n=1927) 1 2 3-5 6-8 ≥9 52 61 50 48 42 p=0.0421 46 38 49 52 58 Describe last sexual partner (n=2068) Just met for the first time Had met recently Known, no steady relationship In a steady relationship Living together, engaged, or married 74 68 64 51 40 p<0.00012 26 30 34 47 59 1Two-sided, unpaired Student's t-test of the association between increasing number of sexual partners in last 12 months and decreasing use of a condom at last sex. 2Two-sided, unpaired Student's t-test of the association increasing stability of relationship and decreasing reported condom use at last sex. Unintended pregnancies—Of the women in the study, 112 (5.8% of those who had ever had sex) reported having had an unintentional pregnancy. Younger women reported lower rates of terminations: 3.3%, 4.4%, and 3.3% of 17, 18, and 19 year old women who had ever had sex, respectively. Additionally, 43 men (5.0% of the men who had ever had sex) reported having had sex that resulted in an unintentional pregnancy. Women reported that 74% of

There is little information on the sexual health and behaviour of young people in New Zealand (NZ). Indications from national statistics on prevalence of sexually transmitted infections and incidence of terminations are that furtherattention is required. In 2009, NZ had an estimated national chlamydia prevalence of 803 per 100,000 people, higher than in previous years and 3-4 times higher than in Australia and the UK.1NZ has high termination of pregnancy (TOP) rates compared with most OECD countries. In 2008, there were 19.7 terminations per 1000 women aged 15-44 per year compared to 19.6 in the USA, 21.3 in Sweden, and 8.7 in the Netherlands and 7.3 in Germany.2 High levels of TOP may reflect good provision of abortion services, poor availability of contraceptive services, or greater sexual activity at younger ages.3The only national survey of sexual behaviour in the general NZ population was the NZ Partner Relations Survey in 1991.4 Birth cohort studies from Dunedin and Christchurch collected some sexual health and behaviour data as the cohorts reached early adulthood 15 and 20 years ago, respectively.5,6The Dunedin cohort study of individuals born in 1972/3 found that the median age of first intercourse was 17 in women and 16 in men in the late 1980s.5 The Christchurch 1977 birth cohort reported on risk behaviours. About 32% of those aged 20-21 reported unprotected sex in the past year, and that those aged 18-21 had an average of 5.5 sexual partners during that timeframe.7University students are a large, relatively easy to reach subgroup who may serve as a sentinel population for young people more generally, notwithstanding some obvious differences. There is no contemporary information regarding the sexual health outcomes and experiences of tertiary students in NZ, but some recent information is available on sexual and other risk behaviour in younger adolescents.The Youth Health Survey of a nationally representative sample of secondary students in NZ, completed in 2001,8 showed that by age 17, 50% of students had ever had sex, 15% of sexually active students didn't use or only sometimes used condoms and/or contraception, and 63% used a condom last time they had sex. In the 2007 iteration, the authors reported no substantial change in behaviour since 2001.9Motivation for a study of sexual health, risks, and experiences amongst tertiary students comes from both this lack of information on sexual health and increasing concern about the potential impact of high levels of risky drinking. A 2005 survey found that NZ university students frequently attributed unsafe, unhappy, and unwanted sexual experiences to drinking.With reference to the preceding four weeks, 5% of women and 8% of men reported unsafe sex, 3% of women and 4% of men had sex they were not happy about at the time, and 8% of women and 9% of men had a sexual experience they later regretted that they attributed to their drinking.Unwanted sexual advances due to another person's drinking negatively affected 21% of women and 12% of men, and 0.5% of both genders reported sexual assault in those four weeks.10 This suggests adverse sexual experiences associated with drinking are fairly common on university campuses, and that the sexual health of university students is worthy of attention.The aims of this study are to better understand the sexual health, risk behaviour, and experiences of the NZ university student population by investigating age of sexual debut, number of partners, choice of partners, condom use, and occurrence of unintended pregnancies and terminations.Methods Design—Cross-sectional data were collected as part of the 2009 Tertiary Student Health Survey, using a confidential online computerised questionnaire. A detailed description of the methods for the previous iterations of this survey has been published11 and is summarised here. Participants—All 8 NZ universities were invited to participate and students from 8 campuses of 6 universities were eventually included. Enrolment lists provided by institutions were used as a sampling frame, from which random samples of full-time, intramural Māori and non-Māori students aged 17-24 years were invited by both letter and email, timed to arrive the same day, to visit a secure website and complete a questionnaire. Overall, 5770 randomly selected students were invited to participate in the 2009 survey. Measures—Information was sought from study participants on their sexual behaviour and experiences through written questions with categorical responses in drop-down menus. The first question in the sexual health section of the questionnaire was: "Have you ever had sexual intercourse?" Those answering "yes" were presented with the rest of the questions. Age at first sex: "How old were you when you first had sexual intercourse?" [<14, 14, 15, 16, 17, 18,19+] Number of partners ever: "How many people have you had sexual intercourse with in your life?" [0,1,2,3,4,5,6,7,8,9,10,10-20, >20 ] Number of partners in the last 12 months: "How many people have you had sexual intercourse with in the last 12 months?" [0,1,2,3,4,5,6,7,8,9,10, 10-20, >20] Last sexual intercourse: "Did you use a condom last time you had sex?" [yes, no] "Had you been drinking alcohol the last time you had sex?" [no, yes, a little, yes a lot] "Thinking about the last time you had sex, which best describes you and your partner..." [we had just met for the first time; we had met recently; we had known each other for a while but didn't have a steady relationship; we had a steady relationship at the time; we were living together or engaged or married] Unintended pregnancies: "Have you ever become pregnant unintentionally?" (women only) "Have you ever got someone pregnant unintentionally" (men only) [no, once, twice, more than twice] Terminations: "Did this result in a termination of pregnancy (abortion)?" (Those reporting unintended pregnancies only) [no, once, twice, more than twice, don't know] Sexual attraction: "What best describes who you feel attracted to?" [opposite sex only, opposite sex mainly, both sexes equally, same sex mainly, same sex only, no attraction] Analysis—Analyses were conducted using survey procedures in Stata version 11 software12 and weighting was used to account for the oversampling of Māori students. Bivariate analyses used chi2 tests, comparisons between groups used two-sided Student's t-tests, and p values < 0.05 were considered statistically significant. Ethical approval—The study was approved by the New Zealand Multi-region Ethics Committee (MEC/05/01/013). Results Demographics—Of the 5770 students invited to participate, 2922 (50.6%) completed the survey while a further 226 (3.9%) began but did not complete the survey. Participants had a median age of 20 and women were over-represented (61% respondents female vs. 39% male), while the university students invited were 57% female and 43% male. Most students lived in close proximity to other students with 71% living in a residential college or sharing a flat/house. Sixty-nine percent of both women and men reported having had sexual intercourse. The characteristics of the study population are described in Table 1. Table 1. Characteristics of the study population, weighted for sampling design Variables Total (n=2922) % Men (n=1140) % Women (n=1782) % Age group 17-19 years 20-21 years 22-24 years 25-26 years 46 37 17 <1 46 35 19 <1 46 39 15 <1 Ethnicity 1 NZ European NZ Māori Chinese Pacific Islands Other 75 29 6 3 9 69 25 6 3 9 80 32 6 3 9 Residence type Share a flat/house Hall of Residence Live with parent/guardian Live in own home/renting Board Other 51 20 23 3 2 1 51 19 25 3 2 1 51 20 22 3 2 1 Ever had sex Yes No Prefer not to answer 69 26 5 69 25 7 69 26 5 1Categories of ethnicity are not mutually exclusive Sexual behaviours—Of students who reported having had sex, the median age at sexual debut was 17 overall (16 for women, 17 for men) and 21% of respondents reported that they had sex before they were 16 years old (24% of women, 16% of men). The distribution of lifetime number of sexual partners was right-skewed, and the median for both women and men was three partners. For the number of sexual partners in the last 12 months the median was just one partner although the distribution shows that about 25% of university students had three or more partners during this time. The majority of students (66%) reported that the person they last had sex with was someone with whom they were in a "steady relationship" or were "living together, engaged, or married". However, 3% of women and 11% of men reported that they had "just met" the person they last had sex with. Only about half of the respondents (54%) reported using a condom the last time they had sex (men 58%, women 51%). There was a trend of decreasing condom use with increasing age (Chi-squared p<0.0001), and women were less likely to use condoms than men (Student's t-test p<0.001). Overall, 32% of respondents reported that they had been drinking the last time they had sex (men 38%, women 29%). Prevalence rates of reported sexual behaviour and risks are presented in Table 2. Table 2. Prevalence of sexual behaviours in participants who had ever had sex, weighted for sampling design Variables Total (n=2017) % Men (%) (n=783) % Women (n=1234) % Age at first sexual intercourse (years) <14 14 15 16 17 18 ≥19 Median 1 5 15 23 24 21 11 17 years 2 4 10 21 29 22 13 17 years 1 5 18 24 22 20 11 16 years Number of sex partners ever 1 2 3 4 5 6-9 10-20 >20 Median 27 16 11 11 9 13 10 3 3 27 15 13 12 8 13 9 3 3 26 17 10 10 9 16 10 2 3 Number of sexual partners in last 12 months 0 1 2 3 4 5 6-9 10-20 >20 Median 5 57 18 8 5 3 1 3 0.3 1 7 54 20 8 6 3 2 0.4 0.4 1 4 59 17 8 5 4 3 1 0.1 1 Last sexual partner Just met for the first time Met recently Known, no steady relationship In a steady relationship Living together/engaged/married 5 8 20 52 14 9 12 22 47 10 3 6 19 55 17 Condom use at last sex Yes No Prefer not to answer 54 43 3 58 39 3 51 46 3 Drinking alcohol at last sex Not at all A little Quite a lot 68 18 14 62 22 16 71 16 13 There was an association between use of a condom at last sex, and both partner choice and number of sexual partners, shown in Table 3. Use of a condom at last sex declined both as number of sexual partners increased (p=0.042) and as partner choice became more stable (p<0.0001). Table 3. Reported condom use at last sex, by reported number of sexual partners in the last 12 months and by last sexual partner, weighted for sampling design Variables Condom used at last sex? Yes (%) No (%) Number of sexual partners in last 12 months (n=1927) 1 2 3-5 6-8 ≥9 52 61 50 48 42 p=0.0421 46 38 49 52 58 Describe last sexual partner (n=2068) Just met for the first time Had met recently Known, no steady relationship In a steady relationship Living together, engaged, or married 74 68 64 51 40 p<0.00012 26 30 34 47 59 1Two-sided, unpaired Student's t-test of the association between increasing number of sexual partners in last 12 months and decreasing use of a condom at last sex. 2Two-sided, unpaired Student's t-test of the association increasing stability of relationship and decreasing reported condom use at last sex. Unintended pregnancies—Of the women in the study, 112 (5.8% of those who had ever had sex) reported having had an unintentional pregnancy. Younger women reported lower rates of terminations: 3.3%, 4.4%, and 3.3% of 17, 18, and 19 year old women who had ever had sex, respectively. Additionally, 43 men (5.0% of the men who had ever had sex) reported having had sex that resulted in an unintentional pregnancy. Women reported that 74% of