Determining vaccine dose-level protection is essential to minimize program costs and increase mass vaccination program feasibility. Currently, a 3-dose vaccination schedule is recommended for both the quadrivalent and bivalent human papillomavirus (HPV) vaccines. Although the primary goal of HPV vaccination programs is to prevent cervical cancer, condyloma related to HPV types 6 and 11 is also prevented with the quadrivalent vaccine and represents the earliest measurable preventable disease outcome for the HPV vaccine.
To examine the association between quadrivalent HPV vaccination and first occurrence of condyloma in relation to vaccine dose in a population-based setting.
An open cohort of all females aged 10 to 24 years living in Sweden (n?=?1,045,165) was followed up between 2006 and 2010 for HPV vaccination and first occurrence of condyloma using the Swedish nationwide population-based health data registers.
Incidence rate ratios (IRRs) and incidence rate differences (IRDs) of condyloma were estimated using Poisson regression with vaccine dose as a time-dependent exposure, adjusting for attained age and parental education, and stratified on age at first vaccination. To account for prevalent infections, models included a buffer period of delayed case counting.
A total of 20,383 incident cases of condyloma were identified during follow-up, including 322 cases after receipt of at least 1 dose of the vaccine. For individuals aged 10 to 16 years at first vaccination, receipt of 3 doses was associated with an IRR of 0.18 (95% CI, 0.15-0.22) for condyloma, whereas receipt of 2 doses was associated with an IRR of 0.29 (95% CI, 0.21-0.40). One dose was associated with an IRR of 0.31 (95% CI, 0.20-0.49), which corresponds to an IRD of 384 cases (95% CI, 305-464) per 100,000 person-years, compared with no vaccination. The corresponding IRDs for 2 doses were 400 cases (95% CI, 346-454) and for 3 doses, 459 cases (95% CI, 437-482). The number of prevented cases between 3 and 2 doses was 59 (95% CI, 2-117) per 100,000 person-years.
Although maximum reduction in condyloma risk was seen after receipt of 3 doses of quadrivalent HPV vaccine, receipt of 2 vaccine doses was also associated with a considerable reduction in condyloma risk. The implications of these findings for the relationship between number of vaccine doses and cervical cancer risk require further investigation.
Comment In: JAMA. 2014 Jun 18;311(23):243924938569
Comment In: JAMA. 2014 Jun 18;311(23):2439-4024938570
Grief over the loss of a family member may cause physical and mental illness, but an association between bereavement and cancer risk has not been established. Based on the Swedish National Cervical Screening Register (1969-2011) including 14,011,269 smears from 2,466,107 women, we conducted two nested case-control studies to examine the associations of bereavement (i.e., loss of a family member due to death) with abnormal cytology (390,310 first abnormal and 1,951,319 normal smears) and in situ/invasive cervical cancer (75,128 case and 375,640 control women), both individually matched on year of birth and screening adherence. Among 1,696 of the control women, we further investigated bereavement in association with human papillomavirus (HPV) infection, both HPV16 and other HPV types. Bereavement was consistently associated with a 4% to 9% increased risk for first abnormal cytology, in situ and invasive cervical cancer (all P
Cites: Health Psychol. 2013 Mar;32(3):337-4422746260
Cites: Cancer Causes Control. 2014 Apr;25(4):499-50624500176
The routine health services collect large amount of samples for biobanking, particularly in clinical laboratory medicine, mainly for clinical diagnostic purposes. These samples provide a large-scale and clinically relevant biobanking infrastructure that can be used for research if these conditions apply. There must be a system for database management that can obtain data on clinical endpoints, vital status, and additional required information via registry linkages. There must be an appropriate ethical system for handling consent for research use. There should be an active effort to optimize the usefulness of clinical biobanks also for research use. Major steps in this direction include measures to stop the ongoing discarding of old samples, reformatting to minimize pick-up times, external quality assurance and formal accreditation of biobanks, building of a dedicated high-quality database that is regularly used for registry linkages, and considerations on whether usefulness and accessibility for research can be optimized by extended saving or pre-treatment of samples. Systematic clinical biobanking could become a major asset for clinical research and public health if biobanking is considered as a routine part of everyday clinical practice, and the science of biobanking is considered an essential part of the science of laboratory medicine.
Vitamin D inhibits the development and growth of prostate cancer cells. Epidemiologic results on serum vitamin D levels and prostate cancer risk have, however, been inconsistent. We conducted a longitudinal nested case-control study on Nordic men (Norway, Finland and Sweden) using serum banks of 200,000 samples. We studied serum 25(OH)-vitamin D levels of 622 prostate cancer cases and 1,451 matched controls and found that both low (/=80 nmol/l) 25(OH)-vitamin D serum concentrations are associated with higher prostate cancer risk. The normal average serum concentration of 25(OH)-vitamin D (40-60 nmol/l) comprises the lowest risk of prostate cancer. The U-shaped risk of prostate cancer might be due to similar 1,25-dihydroxyvitamin D(3) availability within the prostate: low vitamin D serum concentration apparently leads to a low tissue concentration and to weakened mitotic control of target cells, whereas a high vitamin D level might lead to vitamin D resistance through increased inactivation by enhanced expression of 24-hydroxylase. It is recommended that vitamin D deficiency be supplemented, but too high vitamin D serum level might also enhance cancer development.
Immunosuppression involves an inability to control virus infections and increased incidence of virus-associated cancers. Some cancers without known viral etiology are also increased, but data on exactly which cancer forms are increased has been inconsistent. To provide a reliable and generalizable estimate, with high statistical power and long follow-up time, we assessed cancer risks using comprehensive, population-based registries in two different countries and from two different immunosuppressed patient groups (solid organ transplant recipients (OTRs) and long-term dialysis patients (LDPs)). National registries in Denmark and Sweden identified 20,804 OTRs and 31,140 LDPs that were followed up using national cancer registries. Standardized incidence ratios (SIR) compared to the general population were estimated. We found highly similar results, both for the two different countries and for the two different immunosuppressed cohorts, namely an increased incidence for the following specific cancer forms: Non-melanoma skin cancer (NMSC), non-Hodgkin's lymphoma and cancers of the lip, kidney, larynx and thyroid. The SIR for overall cancer among OTRs was 3.5 [n?=?2,142, 95% CI, 3.4-3.7] in Sweden, 2.9 [n?=?1,110, 95% CI, 2.8-3.1] in Denmark and 1.6 [n?=?1,713, 95% CI, 1.5-1.6] among LDP. The SIR for NMSC among OTRs was 44.7 [n?=?994, 95% CI, 42-47.5] in Sweden and 41.5 [n?=?445, 95% CI, 37.8-45.5] in Denmark. The increased SIR for NMSC among LDPs was 5.3 [n?=?304, 95% CI, 4.7-5.9]). In summary, an increased SIR for a specific, similar set of cancer forms is consistently found among the immunosuppressed. Conceivable explanations include surveillance bias and immunosuppression-related susceptibility to viral infections.
Our study used a refined case-control cervical cancer Audit framework to investigate effectiveness of cervical screening, with measures of three screening failures: irregular-participation, cervical cancer developed after cytological abnormalities and after normal screening results. The register-based study included 4,254 cervical cancer cases diagnosed in Sweden during 2002-2011, and 30 population-based controls per case. We used conditional logistic regression models to examine relative risks of cervical cancer in relation to screening participation and screening results in the past two screening rounds from 6 months before cancer diagnosis. We found that women unscreened in past two screening rounds showed four times increased risk of cervical cancer compared to women screened in time (OR = 4.1, 95% CI = 3.8-4.5), and women unscreened in the previous round but screened in the most recent round also showed a statistically significantly elevated risk (OR = 1.6, 95% CI = 1.5-1.8). Women having abnormality in previous two rounds exhibited higher risk of cervical cancer compared to women screened with normal results, while having normal results in the subsequent round after the abnormality also yielded an increased risk (OR = 4.0, 95% CI = 3.2-5.1). Being screened with only normal results was associated with 89% risk reduction for squamous cell cancer, compared to women unscreened, but only 60% reduction for adenocarcinoma. Our findings emphasize the importance of routine participation in cervical screening and suggest that management of abnormalities, as well as sensitivity of the test, warrants improvement especially for preventing cervical adenocarcinoma. The Audit framework serves as routine evaluation model and the findings benchmark for future evaluation of changes in screening practice.
Cervical cancer has increased in Sweden in recent years. The increase is 17% in 2014-15 compared to the reference period 2002-13. The increase is largest for adenocarcinoma (+?31%) and shows remarkable differences between counties, from continued incidence decreases to increases of >80%. The increase is seen in most ages that are offered screening, but is confined to early stage cancers and there is no increase in mortality. Population test coverage of screening has increased since 2002. The Swedish National Cervical Screening Registry has analysed the increase in relation to screening history. The most significant increase (+?30%) is seen in women who had a normal cervical smear (P
To enable incremental optimization of screening, regular reporting of quality indicators is required.
To report key quality indicators and basic statistics about cervical screening in Sweden.
We collected individual level data on all cervical cytologies, histopathologies, human papillomavirus tests and all invitations for cervical screening in Sweden during 2013-2016.
There were over 2,278,000 cervical samples collected in Sweden in 2014-2016. Organized samples (resulting from an invitation) constituted 69% of samples. The screening test coverage of all resident women aged 23-60 was 82%. The coverage has slowly increased for >10 years. There is large variability between counties (from 71% to 92%) over time. There were 25,725 women with high-grade lesions in cytology during 2013-2015. Only 96% of these women had a follow-up histopathology within a year. Cervical cancer incidence showed an increasing trend.
Key quality indicators such as population coverage and follow-up rates were stable or improving, but there was nevertheless an unexplained cervical cancer increase.
OBJECTIVE: We assessed the risk of prostate cancer by exposure to Chlamydia trachomatis. METHOD: Seven hundred thirty eight cases of prostate cancer and 2,271 matched controls were identified from three serum sample banks in Finland, Norway, and Sweden by linkage to the population based cancer registries. RESULTS: A statistically significant inverse association (odds ratio, 0.69; 95% confidence interval, 0.51-0.94) was found. It was consistent by different serotypes and there was a consistent dose-response relationship. CONCLUSION: C. trachomatis infection is not likely to increase the risk of prostate cancer. Whether the inverse relationship is true or due to difficulties in measuring the true exposure in prostatic tissue by serology, confounders or other sources of error remain open.
Human papillomavirus (HPV) persistence is the major cause of cervical cancer, but most HPV infections will not persist and risk factors for HPV persistence are not well known. Chlamydia (C.) trachomatis infection seems to also be associated with cervical cancer. We investigated whether C. trachomatis infection is a risk factor for HPV persistence. In a cohort of 12,527 women participating in a population-based HPV screening trial in Sweden, 6,418 women completed testing for HPV DNA by general primer PCR and typing by reverse dot blot hybridization. On average 19 months later, 303 women that had been HPV-positive and had normal cytology at enrollment completed a new HPV test. Environmental exposures were assessed by an 87-item questionnaire. Previous sexually transmitted infections were also investigated by serology. At follow-up, 44% of the women were positive for the same type of HPV DNA as at enrollment. Persistence correlated with length of follow-up (p