Antoinette Righarts

Chlamydia trachomatis Pgp3 Antibody Persists and Correlates with Self-Reported Infection and Behavioural Risks in a Blinded Cohort Study

Chlamydia trachomatis (Ct) serological studies in populations could help monitor changes in lifetime cumulative risk of infection. We developed a double-antigen sandwich ELISA based on the Ct-specific Pgp3 antigen, then tested blind stored sera from over 800 participants in a New Zealand birth cohort from Dunedin at ages 26, 32 and 38. The double-antigen sandwich ELISA was more sensitive than our previously characterised indirect Pgp3 ELISA. Pgp3 antibody was detected more often in women compared to men and correlated with increasing numbers of sexual partners, self-reported Ct, and younger age at sexual debut in both women and men. At age 26, 24.1% (99/411) of women were Pgp3 seropositive, as were 79.5% (35/44) of those reporting Ct infection; Pgp3 antibody persisted to age 38 in 96.5% (83/86). In men at age 26, the figures were 10.7% (47/442) and 25.0% (6/24), respectively, with high (83.9%) antibody persistence to age 38. At age 38, among those Pgp3 seropositive, 63.3% of women and 83.1% of men had not reported Ct infection. Thus, Ct-specific Pgp3 antibody was detected in most women reporting Ct infection and correlated with risk of infection in those who did not, with most infections remaining undetected. As this antibody persisted for at least twelve years in 96% of these women, serology could be used to evaluate Ct prevention programmes among women.

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.

Prevalence of Chlamydia trachomatis infection in Samoan women aged 18 to 29 and assessment of possible risk factors: a community-based study.

BACKGROUND Knowledge about genital Chlamydia trachomatis (CT) infections in the Pacific is limited. In this study we investigated CT infection in Samoan women. METHODS We recruited women having unprotected sex aged 18 to 29 years from 41 Samoan villages. They completed a questionnaire and provided a urine sample for CT testing by PCR. Associations between CT infection and possible risk factors were explored using logistic regression. RESULTS Altogether, 239 women were recruited; 86 (36.0%; weighted estimate of prevalence: 41.9%; 95% CI: 33.4-50.5%) were positive for CT infection. A higher proportion of women aged 18 to 24 were positive (54/145; 37.2%) than those aged 25 to 29 (32/94; 34.0%; p=0.20). Being single (OR 1.92; 95% CI: 1.02-3.63) and having two or more lifetime sexual partners (OR 3.02; 95% CI: 1.19-7.67) were associated with CT infection; 27.6% of those with one lifetime partner were positive. Participants who had a previous pregnancy were less likely to be positive (OR 0.49; 95% CI: 0.27-0.87). Primiparous and multiparous women were less likely to be positive than nulliparous women (OR 0.54; 95% CI: 0.30-0.99 and OR 0.46; 95% CI: 0.24-0.89, respectively). CONCLUSIONS The prevalence of CT infection in these Samoan women is very high. Further studies, including investigating the prevalence of CT infection in men, and strategies for sustainable control are needed.

Chlamydia trachomatis incidence using self-reports and serology by gender, age period, and sexual behavior in a birth cohort

Background Although understanding chlamydia incidence assists prevention and control, analyses based on diagnosed infections may distort the findings. Therefore, we determined incidence and examined risks in a birth cohort based on self-reports and serology. Methods Self-reported chlamydia and behavior data were collected from a cohort born in New Zealand in 1972/3 on several occasions to age 38 years. Sera drawn at ages 26, 32, and 38 years were tested for antibodies to Chlamydia trachomatis Pgp3 antigen using a recently developed assay, more sensitive in women (82.9%) than men (54.4%). Chlamydia incidence by age period (first coitus to age 26, 26–32, and 32–38 years) was calculated combining self-reports and serostatus and risk factors investigated by Poisson regression. Results By age 38 years, 32.7% of women and 20.9% of men had seroconverted or self-reported a diagnosis. The highest incidence rate was to age 26, 32.7 and 18.4 years per 1000 person-years for women and men, respectively. Incidence rates increased substantially with increasing number of sexual partners. After adjusting age period incidence rates for partner numbers, a relationship with age was not detected until 32 to 38 years, and then only for women. Conclusions Chlamydia was common in this cohort by age 38, despite the moderate incidence rates by age period. The strongest risk factor for incident infection was the number of sexual partners. Age, up to 32 years, was not an independent factor after accounting for partner numbers, and then only for women. Behavior is more important than age when considering prevention strategies.

Strengthening health research capacity from within Samoa.

This article reflects on the challenges of strengthening health research capacity from within Samoa. It examines the status of health research and related curricula in Samoa and discusses the outcomes of a new postgraduate applied social and health research methods course taught in Samoa for the first time from 5 January to 12 February 2010 by the Department of Preventive and Social Medicine, University of Otago in collaboration with the Centre for Samoan Studies, National University of Samoa. The article argues that collaborative health research courses such as this methods paper can fill a curriculum gap in New Zealand and Samoa and contribute directly toward strengthening Samoa health research capacity in ways that benefit both Samoa and New Zealand. This initiative can be a flagship for strategies operating from within Samoa that can build real win-win type partnerships. These can be ably led by Samoans for the ultimate development of an affordable and sustainable quality health and education infrastructure for Samoa.

The prevalence and potential determinants of dysmenorrhoea and other pelvic pain in women: a prospective study

To estimate the prevalence of pelvic pain and model associations with potential demographic, obstetric, gynaecological and psychosocial determinants.

Resolution of infertility and number of children: 1386 couples followed for a median of 13 years

STUDY QUESTION How common were children among infertile couples? SUMMARY ANSWER A total of 61.7% of infertile couples presenting for care subsequently had live born children 13.1 years after first being clinically assessed, with a mean of 1.7 children among those who had at least one. WHAT IS KNOWN ALREADY While the prognoses for infertile couples undertaking specific treatments have been well described, less is known about those not undergoing these treatments or the total number of children. This information is necessary for decision-making in many individual cases; not knowing this has been cited by patients and clinicians as impeding implementation of care. STUDY DESIGN, SIZE, DURATION The sole provider of specialist fertility care for the two southern-most regions in New Zealand enroled 1386 infertile couples from 1998 to 2005 in a longitudinal study with follow-up on all births until the end of 2014. Couples were followed in care for a median of 1.1 years and median follow-up for births was 13.1 years. PARTICIPANTS/MATERIALS, SETTING, METHODS Clinic-collected data were linked to national maternity data to extend follow-up past the end of clinical contact. The primary outcome was the total number of live born children. Hurdle regression was used to investigate factors associated with resolving infertility and the total number of children. MAIN RESULTS AND THE ROLE OF CHANCE Infertility was resolved with a live birth by 61.7% (95% CI 59.1-64.2%) of couples; just over half of all first births were treatment-dependent. Among couples who resolved their infertility, 55.6% (52.2-58.9%) had at least one additional child and the mean number of children was 1.7. While female age strongly influenced outcomes, one-third of women aged 40-41 years had a child, not significantly less than those in their late 30s. The lowest levels of resolution occurred in women aged ≥42 years, couples who were infertile for >4 years and women with a BMI ≥ 35 kg/m2. Moderate obesity did not affect outcomes. LIMITATIONS, REASONS FOR CAUTION The main limitation of this study was insufficient data to investigate male factor infertility outcomes. It is also possible that treatment-dependent resolution could be higher in more recent cohorts with the increased use of ART. WIDER IMPLICATIONS OF THE FINDINGS Outcomes in these couples are comparable to those seen in other studies in high-income countries despite the relatively low contribution of ART. The prognosis for most infertile couples is positive and suggests many will not require treatment. Further research is needed to inform best practice for women in their early forties or with moderate obesity, and to develop prediction models that are more relevant for the initial management of infertility. STUDY FUNDING/COMPETING INTEREST(S) This study was co-funded by a University of Otago PhD Scholarship and the Department of Womens and Childrens Health, University of Otago. There were no competing interests to declare.

Ovulation monitoring and fertility knowledge: Their relationship to fertility experience in a cross-sectional study

Various aspects of fertility knowledge, including the timing of the fertile window, have consistently been found to be poor. Limited evidence also suggests ovulation monitoring to time intercourse could be common. However, there have been no studies that compare these two aspects of fertility and womens fertility/infertility experiences.

Do Reports of Age and Circumstances of First Intercourse Differ in a Birth Cohort When Asked Seventeen Years Apart

Conclusions about temporal changes in age and circumstances of first intercourse are generally derived from retrospective reports by people of various ages in cross-sectional studies, with an inherent assumption of no bias stemming from time since the event. We examined this assumption through repeated questions on age and circumstances of first heterosexual intercourse (FHI) at ages 21 and 38 in a birth cohort. Despite considerable movement in individual reports, there was no bias in reported age of FHI. However, a greater proportion of both men and women stated at the later assessment both partners had been equally willing (versus persuading or persuaded). The distribution of current views of the appropriateness of the timing did not differ markedly between assessments, although there were many individual changes. Reports of contraceptive usage were similar at the two assessments for men but differed among women, mainly through more reporting that they could not remember. These findings imply that among cohorts born in the 1970s, there is no bias in reports of age of FHI many years after the event, and views on the appropriateness of timing persist. However, time biases reports in favor of a more mutual willingness.

P3.055 Herpes Simplex Type 2 (HSV-2) Incidence by Age and Sex Over Four Age Periods to Age 38 Years in a Birth Cohort

Background Here we report direct measures of HSV-2 incidence over four age periods to age 38 in the Dunedin Multidisciplinary Health and Development Study, a long-running New Zealand birth cohort. Methods Information on sexual behaviour and STIs was obtained at ages 21, 26, 32 and 38. Sera were collected at these ages and tested for HSV-2 antibodies using an indirect enzyme-linked immunosorbent assay. Incidence rates for four age periods (< 21, 21–26, 26–32 and 32–38) were calculated and compared by age and sex. Results The seroprevalence of HSV-2 antibodies at age 38 was 14.0% (63/451) for men and 23.7% (107/451) for women (p = 0.001). The number becoming HSV-2 positive in each age period, and the associated incidence rate per 1000 person-years (95% CIs), are shown below. The peak period of HSV-2 risk (after adjustment for number of sexual partners) was 21–26 for women, and 26–32 for men. It was significantly higher for women in the period 21–26. Conclusion In this birth cohort HSV-2 is common, more so in women. The elevated risk for people in their twenties, that peaks later among men, is likely due to increasing prevalence among their partners. However, this did not result in continued increasing incidence into their thirties as would be expected. The most plausible explanation for the drop in incidence is that individuals’ infectivity is decreasing with time, so that while prevalence among partners continues to rise, those with HSV-2 will on average have been infected for longer and be less infectious. Abstract P3.055 Table 1 Incidence of HSV-2 infection per 1,000 person-years for (a) Men and (b) Women First coitus to 21 Age 21–26 Age 26–32 Age 32–38 Incidence Incidence Incidence Incidence (a) 6.8 (3.7, 12.2) (a) 7.6 (4.6, 12.4) (a) 14.1 (10.0, 19.9) (a) 5.1(2.8, 9.2) (b) 8.6 (5.1, 14.5) (b) 19.1 (13.9, 26.3) (b) 15.8 (11.1, 22.4) (b) 6.8 (4.0, 11.8)