Thea van Roode

Child sexual abuse and persistence of risky sexual behaviors and negative sexual outcomes over adulthood: Findings from a birth cohort ☆

OBJECTIVES To determine the impact of child sexual abuse (CSA) on adult sexual behaviors and outcomes over three age periods. METHODS A longitudinal study of a birth cohort born in Dunedin, New Zealand in 1972/1973 was used. Information on CSA was sought at age 26, and on sexual behaviors and outcomes at ages 21, 26, and 32. Comparisons were over the whole period from age 18 to 32, then for the three age periods from age 18 to 21, 21 to 26, and 26 to 32, adjusting for measures of family environment. RESULTS Overall, 465 women and 471 men (91.9% of the surviving cohort) answered questions about CSA. Contact CSA was reported by 30.3% of women and 9.1% of men. For abused women, significantly increased rates were observed for number of sexual partners, unhappy pregnancies, abortion, and sexually transmitted infections from age 18 to 21; with rates approaching those of nonabused over time. Conversely, for abused men rates were not significantly elevated in the youngest age period, but were for number of partners from age 26 to 32 and acquisition of herpes simplex virus type 2 from age 21 to 32. CONCLUSIONS Gender and age are critical when considering the effect of CSA. While the profound early impact of CSA demonstrated for women appears to lessen with age, abused men appear to carry increased risks into adulthood. PRACTICE IMPLICATIONS CSA is common and should be considered when young women present with unwanted conceptions or seek multiple terminations, and when men continue to have high risk sexual behavior into adulthood. Furthermore, if CSA is disclosed, sexual risks in adulthood need to be considered.

Circumcision and Risk of Sexually Transmitted Infections in a Birth Cohort

OBJECTIVE To determine the impact of early childhood circumcision on sexually transmitted infection (STI) acquisition to age 32 years. STUDY DESIGN The circumcision status of a cohort of children born in 1972 and 1973 in Dunedin, New Zealand was sought at age 3 years. Information about STIs was obtained at ages 21, 26, and 32 years. The incidence rates of STI acquisition were calculated, taking into account timing of first sex, and comparisons were made between the circumcised men and uncircumcised men. Adjustments were made for potential socioeconomic and sexual behavior confounding factors where appropriate. RESULTS Of the 499 men studied, 201 (40.3%) had been circumcised by age 3 years. The circumcised and uncircumcised groups differed little in socioeconomic characteristics and sexual behavior. Overall, up to age 32 years, the incidence rates for all STIs were not statistically significantly different-23.4 and 24.4 per 1000 person-years for the uncircumcised and circumcised men, respectively. This was not affected by adjusting for any of the socioeconomic or sexual behavior characteristics. CONCLUSIONS These findings are consistent with recent population-based cross-sectional studies in developed countries, which found that early childhood circumcision does not markedly reduce the risk of the common STIs in the general population in such countries.

Male Circumcision and Serologically Determined Human Papillomavirus Infection in a Birth Cohort

Circumcision has been reported to protect against infection with human papillomavirus (HPV) in men, but results have been inconsistent. We followed males in a birth cohort born in Dunedin, New Zealand, in 1972 and 1973 from age 3 to 32 years. Seropositivity at age 32 years for the oncogenic types HPV-16 and 18, and the nononcogenic types 6 and 11, was studied in relation to maternal reports of circumcision status at age 3 for 450 men. Seropositivity to any of these types was associated with lifetime number of sexual partners (P = 0.03), and lower moral-religious emphasis of the family of origin (P < 0.001). Circumcision was not found to be protective, with the adjusted odds ratio (95% confidence interval) for HPV6/11/16/18 seropositivity among the circumcised compared with the uncircumcised being 1.4 (0.89-2.2). (Cancer Epidemiol Biomarkers Prev 2009;18(1):177–83)

Longitudinal Study of Self-reported Sexually Transmitted Infection Incidence by Gender and Age up to Age Thirty-two Years

Objectives: To examine how incidence of self-reported sexually transmitted infections (STIs) varies by gender and age, and the factors that influence this. Methods: A longitudinal study of a cohort born in Dunedin, New Zealand in 1972/1973. They were questioned about STIs and sexual behavior at age 21, 26, and 32 years (1993–2005). Incidence rates were calculated over 3 age periods and compared using Poisson regression. Results: Of the 1037 members of the original cohort, 92% or more of survivors completed the computer questionnaire at each age. Incidence rates of STIs from first coitus to age 21, age 21 to 26, and age 26 to 32, were 2.0, 3.2, and 2.0 per 100 person-years, respectively for men and 4.4, 3.0, and 1.4 per 100 person-years, respectively for women. After adjustment for sexual behavior, rates for men were elevated from age 21 to 26 compared with first coitus to 21 years of age [incidence rate ratio (IRR) = 1.9, 95% confidence interval (CI) 1.3 to 2.8), but not from age 26 to 32 (IRR = 1.1, 95% CI 0.70–1.9). For women, adjusted rates decreased with age; from 21 to 26 compared with first coitus to 21 (IRR = 0.79, 95% CI 0.56–1.1) and further from 26 to 32 (IRR = 0.39, 95% CI 0.27–0.57). Conclusions: These unique data, comprising repeated assessment of reported behaviors and STIs in the same population, show that the period before age 21 is a time of special risk for STIs for women and of lower risk for men. The low risk among women aged 26 to 32 years after adjustment for sexual behavior warrants further investigation.

Herpes simplex virus type 2 status at age 26 is not related to early circumcision in a birth cohort.

Objective: The objective of this study was to determine if circumcision in early childhood affects the risk of acquiring herpes simplex virus type 2 (HSV-2) infection. Study: Study members were born in 1972–1973 in Dunedin, New Zealand. Circumcision status was sought at age 3, when the cohort was established. Information about sexual behavior was obtained at ages 21 and 26. Serum was tested for HSV-2 antibodies at age 26 for 435 men (82.9% of the surviving cohort). Results: Of eligible men, 40.2% had been circumcised. The prevalence of HSV-2 antibodies was 7.3% in uncircumcised men and 7.4% in circumcised men. Social and sexual factors were very similar between the 2 groups and adjustment had no effect on the association (odds ratio, 1.1; 95% confidence interval, 0.46–2.5). Seroconversion rates according to years since first sexual intercourse were 0.85 and 0.86 per 100 person-years for uncircumcised and circumcised men. Conclusion: The results support a lack of association between circumcision status and HSV-2 acquisition, although a small effect cannot be ruled out.

HSV-2 incidence by sex over four age periods to age 38 in a birth cohort.

Objectives To examine herpes simplex virus type 2 (HSV-2) incidence over four periods to age 38 in a birth cohort, and to compare risks for men and women, taking into account sexual behaviour. Methods At ages 21, 26, 32 and 38, participants in the Dunedin Multidisciplinary Health and Development Study were invited to provide serum for HSV-2 serology, and information on sexual behaviour. HSV-2 incidence rates were calculated for four age periods, and comparisons made by sex and period, taking into account number of sexual partners. Results By age 38, 17.3% of men and 26.8% of women had ever been seropositive for HSV-2. Incidence peaked for women from age 21 to 26 (19.1 per 1000 person-years) and men from age 26 to 32 (14.1 per 1000 person-years); it fell markedly for both from age 32 to 38 (5.1 and 6.8 per 1000 person-years for men and women, respectively). Overall risk was significantly higher for women: adjusted incidence rate ratio 1.9 (95% CI 1.4 to 2.7); the sex difference was most marked from age 21 to 26 (3.4, 95% CI 1.9 to 6.3). Conclusions Our findings are consistent with a greater biological susceptibility to HSV-2 among women, and with the increasing risk to the early/mid-20s for women and late 20s/early 30s for men, being driven by an increasing pool of prevalent infection. The reduced risk in the mid-30s is consistent with declining infectivity of long-term prevalent infections.

Cumulative incidence of infertility in a New Zealand birth cohort to age 38 by sex and the relationship with family formation

OBJECTIVE To estimate the cumulative incidence of infertility for men and women in a population-based sample. DESIGN Longitudinal study of a birth cohort. SETTING Research unit. PATIENT(S) A population-based birth cohort of 1,037 men and women born in Dunedin, New Zealand, between 1972 and 1973. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Cumulative incidence of infertility by age 32 and 38, distribution of causes and service use for infertility, live birth subsequent to infertility, and live birth by age 38. RESULT(S) The cumulative incidence of infertility by age 38 ranged from 14.4% to 21.8% for men and from 15.2% to 26.0% for women depending on the infertility definition and data used. Infertility, defined as having tried to conceive for 12 months or more or having sought medical help to conceive, was experienced by 21.8% (95% confidence interval [CI], 17.7-26.2) of men and 26.0% (95% CI, 21.8-30.6) of women by age 38. For those who experienced infertility, 59.8% (95% CI, 48.3-70.4) of men and 71.8% (95% CI, 62.1-80.3) of women eventually had a live birth. Successful resolution of infertility and entry into parenthood by age 38 were much lower for those who first experienced infertility in their mid to late thirties compared with at a younger age. CONCLUSION(S) Comparison of reports from two assessments in this cohort study suggests infertility estimates from a single cross-sectional study may underestimate lifetime infertility. The lower rate of resolution and entry into parenthood for those first experiencing infertility in their mid to late thirties highlights the consequences of postponing parenthood and could result in involuntary childlessness and fewer children than desired.

Patterns of sexual partnering and reproductive history: associations with timing of first birth in a birth cohort.

CONTEXT The associations between timing of first live birth and previous sexual behavior and pregnancies are not well understood. METHODS Members of a 1972-1973 New Zealand birth cohort were surveyed at ages 21, 26 and 32 about their sexual and reproductive histories; 506 men and 479 women participated in at least one assessment. Relative risks and 95% confidence intervals were calculated using Poisson regression to examine associations between the likelihood of first live birth at specific ages (prior to age 21, at age 21-25, at age 26-31) and selected characteristics. RESULTS Birth prior to age 21 was more likely for men and women who initiated intercourse before age 15 (relative risks, 3.1 and 2.0, respectively), and less likely for those who initiated at age 18 or later (0.3 and 0.1, respectively), than for those aged 15-17 at first coitus. Prior miscarriage was associated (although sometimes marginally) with an elevated likelihood of first birth across genders and ages (1.7-1.8). Prior abortion was associated with an elevated likelihood of first birth at age 21-25 for women (1.6) and a reduced likelihood at age 26-31 for men (0.5). Having multiple sexual partners at age 21-25 was negatively associated with the likelihood of a first birth at age 26-31 for men. Marriage and cohabitation were positively associated with birth timing. CONCLUSIONS Early sexual initiation and relationship instability may promote parenthood at younger ages, whereas greater relationship stability may do so at older ages.

Consistency and reliability of self-reported lifetime number of heterosexual partners by gender and age in a cohort study

Background: The reported number of sexual partners is a variable used extensively in sexual health research. However, the reliability and consistency of this measure, and the statistical assessment of these attributes, are not well understood. Methods: Using data at ages 21, 26, and 32 years from a New Zealand birth cohort, we compared responses on the lifetime number of heterosexual sex partners to assess reliability and consistency. Differences by gender and age were considered, and the effect of number of sexual partners. A variety of analytical methods were used to explore statistical challenges of these data including variance estimation, fractional polynomial transformations, and quantile regression. Results: We found some level of discrepancy between reports of the number of sexual partners when assessed at different times is common, driven by those reporting a high number of partners who were disproportionately men. Men reported a higher lifetime number of partners than women at each age, and there were statistically significant differences by gender in (a) consistency between reports at different ages, and (b) reliability of reports as measured by both the Intraclass Correlation Coefficient and the Kappa statistic. Conclusions: When considering reliability, multiple statistical approaches are necessary or conclusions can be misleading. Variance components should be examined when considering the Intraclass Correlation Coefficient. When modelling, robust methods like fractional polynomials and quantile regression should be employed to accommodate nonlinearity. Sensitivity analyses excluding participants whose partner number is in the upper 5% to 25% are informative, as these were shown to have the highest discrepancies.

Life-Course Relationship between Socioeconomic Circumstances and Timing of First Birth in a Birth Cohort

Objectives This study examines the influence of socioeconomic circumstances in childhood (childhood SES) and adulthood (adult SES) on timing of first birth by age 37. Methods A longitudinal study of a 1972–1973 New Zealand birth cohort collected information on socioeconomic characteristics from age 3–32 and reproductive histories at 21, 26, 32 and 38; information on first birth was available from 978 of the original 1037. Relative Risks (RR) and 95% Confidence Intervals (CI) were calculated using Poisson regression to examine first live birth prior to age 21, from 21–25, from 26–31, and from 32–37, by socioeconomic characteristics at different ages. Results Overall, 68.5% of men had fathered a child and 75.9% of women had given birth, by age 37; with overall differences in parenthood to age 31 for men, and 37 for women evident by childhood SES. While parenthood by age 20 was strongly associated with lower childhood SES for both sexes, first entry into motherhood from 32–37 was more likely with higher adult SES at age 32 (RR = 1.8, 95% CI 1.1–3.0 for medium and RR = 1.9, 95% CI 1.1–3.3 for high compared with low). Education also differientated age at parenthood, with those with higher education more likely to defer fatherhood past age 31, and motherhood past age 25 followed by a period of increased likelihood of motherhood for women with higher levels of education from age 32–37 (RR = 1.4, 95% CI 0.87–2.2 and RR = 1.7, 95% CI 1.1–2.6 for medium and high respectively compared with low). Conclusions SES varies across the lifecourse, and SES at the time has the strongest association with first births at that time. Low childhood SES drives adolescent parenthood, with resulting cumulative differences in parenthood past age 30. Those with more education and higher adult SES are deferring parenthood but attempt to catch up in the mid to late thirties.