Prevalence of Human Papillomavirus (HPV) and HPV Type Distribution in Penile Samples in Young Men in Denmark: Results 10 Years After Implementation of a Girls-Only HPV Vaccination Program.

BACKGROUND: In Denmark, a girls-only human papillomavirus (HPV) vaccination program was initiated in 2008-2009. The study aim was to assess the HPV prevalence and type distribution in younger men prior to HPV vaccination in men. METHODS: The study population was younger men who attended information days regarding military service. At random days (2019-2020), 280 men were included. We collected questionnaire data regarding risk factors for HPV infection and a penile swab for HPV testing. We compared results in this study with those from a previous study of young men (2006-2007). RESULTS: The majority of participants (94%) were 18-20 years old. The median number of lifetime sexual partners was 4. Altogether, 130 men (46.4%) were HPV positive. No infections with HPV types 6, 11, 16, 18, 31, and 45 were detected. The most frequent type was HPV-51 (detected in 11.1%). Comparison showed that the odds of high-risk HPV type infection were higher in 2019-2020 (prevalence odds ratio [POR], 1.7 [95% confidence interval {CI}, 1.1-2.7]) compared with 2006-2007. In contrast, the odds were lower (POR, 0.3 [95% CI, .1-.6]) for HPV types targeted by the 9-valent HPV vaccine. CONCLUSIONS: The multicohort girls-only vaccination program has to a large degree protected young men against the HPV types included in the licensed vaccines. This does not speak against gender-neutral vaccination as the HPV prevalence is still high, although consisting largely of less carcinogenic HPV types.

Maternal use of hormonal contraception and risk of childhood autism spectrum disorders: A Parental Exposures and Child Health (PECH) cohort study.

A recent hypothesis suggests that maternal hormonal contraception use has contributed to the increasing incidence of autism spectrum disorders (ASD). We used a nationwide population-based cohort (the PECH cohort) including 1,056,149 Danish children born in the period January 1, 1998, to December 31, 2014, to assess associations between maternal hormonal contraception use and childhood ASD (end of follow-up: December 31, 2017). Maternal hormonal contraception use was grouped as "recent use" (≤ 3 months before pregnancy start or during pregnancy), "previous use" (>3 months before pregnancy start) and "never use", except for few products. Incidence rate ratios (IRRs) were estimated using Poisson regression. During follow-up of nearly 12 million person-years, 19,996 children were diagnosed with ASD. A slightly higher IRR was observed for maternal recent use of any hormonal contraception, compared to previous use. This association was largely driven by the non-oral progestin-only products, and associations were especially seen for infantile autism and other/unspecified ASD. An increased IRR of infantile autism was also observed for recent use of the oral progestin-only products, compared to previous use. Our results suggest that maternal use of hormonal contraception may be associated with ASD risk in children, especially for the progestin-only products.

Prenatal exposure to nitrofurantoin and risk of childhood leukaemia: a registry-based cohort study in four Nordic countries.

BACKGROUND: Studies have suggested increased risks of childhood leukaemia after prenatal exposure to antibiotics, particularly nitrofurantoin. However, these findings may be related to the underlying maternal infection. This multinational study aimed to investigate the association between prenatal nitrofurantoin exposure and childhood leukaemia while accounting for maternal infection. METHODS: In a population-based cohort study of children born in Denmark, Finland, Norway or Sweden from 1997 to 2013, prenatal exposure to nitrofurantoin or pivmecillinam (active comparator) was ascertained from national Prescription Registries. Childhood leukaemia was identified by linkage to national Cancer Registries. Poisson regression was used to estimate incidence rate ratios (IRRs) and incidence rate differences (IRDs) with inverse probability of treatment weights applied to account for confounding. RESULTS: We included 44 091 children prenatally exposed to nitrofurantoin and 247 306 children prenatally exposed to pivmecillinam. The children were followed for 9.3 years on average (standard deviation 4.1). There were 161 cases of childhood leukaemia. The weighted IRR for prenatal nitrofurantoin exposure when compared with pivmecillinam was 1.34 (95% confidence interval 0.88, 2.06), corresponding to an IRD of 15 per million person-years. Higher point estimates were seen for first- and third-trimester exposure. There was no evidence of a dose-response relationship. CONCLUSIONS: Prenatal exposure to nitrofurantoin was not substantially associated with childhood leukaemia, although a slightly elevated IRR with confidence intervals including the null was observed, corresponding to a small absolute risk. The lack of a dose-response relationship and a clear biological mechanism to explain the findings suggests against a causal association.

The association of reproductive factors with risk of non-epithelial ovarian cancer and comparison with serous ovarian cancer.

OBJECTIVE: To examine the association between reproductive factors and risk of non-epithelial ovarian cancer and to compare the associations with those in serous ovarian cancer. METHODS: From the Danish Cancer Registry, we identified all ovarian cancer cases (≥20 years old at diagnosis) of germ cell (n = 188), sex cord-stromal (n = 116), or serous (n = 4854) histology during 1982-2016. For each case, 15 age-matched female controls were selected with risk set sampling. Reproductive history was obtained from nationwide registries. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between reproductive factors and the three ovarian cancer types. RESULTS: Compared with nulliparity, ever giving birth was associated with increased odds for germ cell tumors (OR = 1.28, 95% CI: 0.85-1.93) and decreased odds for sex cord-stromal (OR = 0.74, 95% CI: 0.44-1.26) and serous tumors (OR = 0.70, 95% CI: 0.64-0.76). Infertility decreased odds for germ cell tumors (OR = 0.63, 95% CI: 0.23-1.76) but increased odds for sex cord-stromal tumors (OR = 2.20, 95% CI: 0.89-5.43) and serous tumors (OR = 1.97, 95% CI: 1.69-2.30). Finally, use of oral contraceptives decreased the odds for all three tumor types (germ cell: OR = 0.50, 95% CI: 0.29-0.87; sex cord-stromal: OR = 0.40, 95% CI: 0.13-1.22; serous: OR = 0.50, 95% CI: 0.40-0.62). CONCLUSIONS: Reproductive factors affected the risk of sex cord-stromal and serous ovarian cancer similarly with decreased risk associated with parity and use of oral contraceptives. Oral contraceptives also seemed to decrease the risk of germ cell tumors, whereas parity was associated with increased risk.

Maternal Medication Use and Childhood Cancer in Offspring-Systematic Review and Considerations for Researchers.

Cancer is an important cause of childhood mortality, yet the etiology is largely unknown. A combination of pre- and postnatal factors is thought to be implicated, including maternal medication use. We aimed to provide: 1) a systematic review of peer-reviewed publications on associations between maternal medication use and childhood cancer, with a focus on study design and methodology; and 2) suggestions for how to increase transparency, limit potential biases, and improve comparability in studies on maternal medication use and childhood cancer. We conducted a systematic search in the PubMed, Embase, Scopus, Cochrane, and Web of Science databases to June 8, 2020. Altogether, 112 studies were identified. The reviewed studies were heterogeneous in study design, exposure, and outcome classification. In 21 studies (19%), the outcome was any childhood cancer. Of the 91 papers that reported on specific types of cancer, 62% did not report the cancer classification system. The most frequently investigated medication groups were sex hormones (46 studies, excluding fertility medications), and antiinfectives (37 studies). Suggestions for strengthening future pharmacoepidemiologic studies on maternal medication use and childhood cancer relate to choice of cancer classification system, exposure windows, and methods for identification of, and control for, potential confounders.

Maternal use of hormonal contraception and risk of childhood ADHD: a nationwide population-based cohort study.

Although maternal use of hormones has been suspected of increasing the risk for childhood attention-deficit/hyperactivity disorder (ADHD), no study has examined hormonal contraception use in this context. We examined the association between maternal hormonal contraception use before or during pregnancy and ADHD risk in children. This nationwide population-based cohort study included 1,056,846 children born in Denmark between 1998 and 2014. Prescriptions for hormonal contraceptives redeemed by the mother was categorized as: no use, previous use (> 3 months before pregnancy), and recent use (≤ 3 months before or during pregnancy). Children were followed for ADHD, from birth until 31 December 2015. Cox proportional hazard models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). During 9,819,565 person-years of follow-up (median: 9.2), ADHD was diagnosed or a prescription for ADHD medication redeemed for 23,380 children (2.2%). The adjusted HR for ADHD was higher in children of mothers who had previously (HR 1.23; 95% CI 1.18-1.28) or recently (HR 1.30; 95% CI 1.24-1.37) used hormonal contraception than in those of mothers with no use. The highest estimates were seen for use of non-oral progestin products with HRs of 1.90 (95% CI 1.59-2.26) for previous use, 2.23 (95% CI 1.96-2.54) for recent use, and 3.10 (95% CI 1.62-5.91) for use during pregnancy. Maternal use of hormonal contraception was associated with an increased risk for ADHD in the offspring; more pronounced for non-oral progestin-only than other products.