Age-specific Incidence Data Research Articles

Shifting patterns of dengue three years after Zika virus emergence in Brazil

In 2015, the Zika virus (ZIKV) emerged in Brazil, leading to widespread outbreaks in Latin America. Following this, many countries in these regions reported a significant drop in the circulation of dengue virus (DENV), which resurged in 2018-2019. We examine age-specific incidence data to investigate changes in DENV epidemiology before and after the emergence of ZIKV. We observe that incidence of DENV was concentrated in younger individuals during resurgence compared to 2013-2015. This trend was more pronounced in Brazilian states that had experienced larger ZIKV outbreaks. Using a mathematical model, we show that ZIKV-induced cross-protection alone, often invoked to explain DENV decline across Latin America, cannot explain the observed age-shift without also assuming some form of disease enhancement. Our results suggest that a sudden accumulation of population-level immunity to ZIKV could suppress DENV and reduce the mean age of DENV incidence via both protective and disease-enhancing interactions.

Abstract B145: Validation of a colorectal cancer risk prediction model in US Black women

Abstract Background: The National Cancer Institute’s Colorectal Cancer Risk Assessment Tool (NCI-CCRAT) estimates an individual's five-year risk of developing colorectal cancer. It was developed by estimating relative risks from a population of US White women and men and incorporating race, gender, and age-specific incidence data from population-based cancer registries. However, the model performance has not been assessed for Black Americans, who have the highest colorectal cancer incidence and mortality rates of any US racial/ethnic group. Methods: The NCI-CCRAT estimates the absolute risk of colorectal cancer based on an individual’s age, sex, family history of colorectal cancer, sigmoidoscopy/colonoscopy, polyps, smoking, physical activity, regular aspirin/nonsteroidal anti-inflammatory drug (NSAID) use, vegetable intake, body mass index, and hormone replacement therapy use. Validation of the NCI-CCRAT was performed using prospective data from 57,558 participants ages 40 to 84 years in the Black Women's Health Study (BWHS). We predicted 5-year absolute risk using data from 2001 through 2015 in three 5-year prediction periods: 2001-2005, 2006-2010, and 2011-2015. To assess model performance, we computed calibration by comparing the expected number of colorectal cancer cases predicted by the model to the observed number of cases (E/O) in the BWHS overall and in subgroups of the population. We assessed discriminatory accuracy by calculating the area under the curve (AUC). Results: During follow-up from 2001 through 2015 (634,512 person-years), 433 BWHS participants developed invasive colorectal cancer. Based on the NCI-CCRAT, 543 cases were expected. The NCI-CCRAT was well-calibrated in the first 5-year prediction period (2001-2005 E/O=1.03, 95% CI: 0.88–1.21), but the model overestimated risk in the subsequent 5-year prediction periods, with E/O=1.30 for 2006-2010 and E/O=1.44 for 2011-2015. The overall E/O ratio was 1.25 (95% confidence interval: 1.14–1.38), indicating that NCI-CCRAT overestimated the number of cases in this population of Black women. Of note, associations with colorectal cancer were weaker in the BWHS than in the development cohort for vigorous physical activity, aspirin/NSAID use, vegetable intake, and body mass index. We estimated discriminatory accuracy only for the first 5-year prediction period (2001-2005, N cases=151) for which the model was well calibrated, and obtained an age-adjusted AUC of 0.61 (95% CI: 0.57–0.66). Conclusions: The NCI-CCRAT overestimated the overall number of colorectal cancer cases by 25% in this prospective cohort of Black women, possibly due to population-specific differences in the relative risks of key factors driving colorectal cancer incidence. Discriminatory accuracy was similar to measures from the original validation cohort of White women and men. Impact: This study suggests that further research is needed to determine the most important predictors of colorectal cancer etiology in Black women and to develop and test a colorectal cancer risk prediction model for Black Americans. Citation Format: Jessica L. Petrick, Nelsy Castro-Webb, Gary R. Zirpoli, Kerrie P. Nelson, Julie R. Palmer, Ruth M. Pfeiffer. Validation of a colorectal cancer risk prediction model in US Black women [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B145.

Estimation of single-dose varicella vaccine effectiveness in South Korea using mathematical modeling

ABSTRACT In South Korea, despite the implementation of a universal single-dose vaccination program for children aged 12–15 months in 2005, the varicella incidence rate remains significant. Prior case-control studies have reported that currently used varicella vaccines are extremely inefficacious. We estimated vaccine effectiveness (VE) by fitting a dynamic transmission model to age-specific varicella incidence data from 2007 to 2015 and available vaccine coverage data. The initial vaccine efficacy and primary failure rates were estimated to be 61.1% and 38.9%, respectively. The average duration of protection was 21.4 years. The mean VE [(1-relative risk) %] for the simulated data of 2004–2014 birth cohorts decreased from 59.8% to 50.7% over 9 years. This mathematical modeling study demonstrated that the single-dose vaccine exhibits moderate effectiveness, and a high proportion of primary failure could be a main cause of breakthrough infections. Therefore, a two-dose vaccination strategy should be considered.

The current burden of Japanese encephalitis and the estimated impacts of vaccination: Combining estimates of the spatial distribution and transmission intensity of a zoonotic pathogen.

Japanese encephalitis virus (JEV) is a major cause of neurological disability in Asia and causes thousands of severe encephalitis cases and deaths each year. Although Japanese encephalitis (JE) is a WHO reportable disease, cases and deaths are significantly underreported and the true burden of the disease is not well understood in most endemic countries. Here, we first conducted a spatial analysis of the risk factors associated with JE to identify the areas suitable for sustained JEV transmission and the size of the population living in at-risk areas. We then estimated the force of infection (FOI) for JE-endemic countries from age-specific incidence data. Estimates of the susceptible population size and the current FOI were then used to estimate the JE burden from 2010 to 2019, as well as the impact of vaccination. Overall, 1,543.1 million (range: 1,292.6-2,019.9 million) people were estimated to live in areas suitable for endemic JEV transmission, which represents only 37.7% (range: 31.6-53.5%) of the over four billion people living in countries with endemic JEV transmission. Based on the baseline number of people at risk of infection, there were an estimated 56,847 (95% CI: 18,003-184,525) JE cases and 20,642 (95% CI: 2,252-77,204) deaths in 2019. Estimated incidence declined from 81,258 (95% CI: 25,437-273,640) cases and 29,520 (95% CI: 3,334-112,498) deaths in 2010, largely due to increases in vaccination coverage which have prevented an estimated 314,793 (95% CI: 94,566-1,049,645) cases and 114,946 (95% CI: 11,421-431,224) deaths over the past decade. India had the largest estimated JE burden in 2019, followed by Bangladesh and China. From 2010-2019, we estimate that vaccination had the largest absolute impact in China, with 204,734 (95% CI: 74,419-664,871) cases and 74,893 (95% CI: 8,989-286,239) deaths prevented, while Taiwan (91.2%) and Malaysia (80.1%) had the largest percent reductions in JE burden due to vaccination. Our estimates of the size of at-risk populations and current JE incidence highlight countries where increasing vaccination coverage could have the largest impact on reducing their JE burden.

Impact of diagnostic accuracy on the estimation of excess mortality from incidence and prevalence: simulation study and application to diabetes in German men.

Aggregated data about the prevalence and incidence of chronic conditions is becoming more and more available. We recently proposed a method to estimate the age-specific excess mortality in chronic conditions from aggregated age-specific prevalence and incidence data. Previous works showed that in age groups below 50 years, estimates from this method were unstable or implausible. In this article, we examine how limited diagnostic accuracy in terms of sensitivity and specificity affects the estimates. We use a simulation study with two settings, a low and a high prevalence setting, and assess the relative importance of sensitivity and specificity. It turns out that in both settings, specificity, especially in the younger age groups, dominates the quality of the estimated excess mortality. The findings are applied to aggregated claims data comprising the diagnoses of diabetes from about 35 million men in the German Statutory Health Insurance. Key finding is that specificity in the lower age groups (<50 years) can be derived without knowing the sensitivity. The false-positive ratio in the claims data increases linearly from 0.5 per mil at age 25 to 2 per mil at age 50. As a conclusion, our findings stress the importance of considering diagnostic accuracy when estimating excess mortality from aggregated data using the method to estimate excess mortality. Especially the specificity in the younger age-groups should be carefully taken into account.

Geriatric infections: Decreased immunity or evolved opportunists?

In host–parasite co-evolution, parasites are assumed to have an advantage owing to their shorter generation time. Evolution of pathogens within the lifetime of a host individual is implicated as a strong selective force in the evolution of sex and aging in the host. However, this assumption or its testable predictions have not been examined empirically. We classified infectious bacteria and viruses into those that can have continued long-term existence on the host body (group 1) versus those that have only a short-term interaction during an active infection (group 2). We surveyed the literature for age-specific incidence data about infections from both the groups. The age trends of the two groups show contrasting patterns. The incidence of infections by all group 1 pathogens showed a 2.28- to 28-fold increase in older ages. In group 2, 6 out of the 9 pathogens showed a significant declining trend in incidence with age. In both groups, there was greater mortality or morbidity among the infected in the old-age classes. These patterns are better explained by pathogen evolution than by age-related decline in immunity. Electronic supplementary materialThe online version of this article (10.1007/s12038-020-0025-x) contains supplementary material, which is available to authorized users.

Forecasting the impact of population ageing on tuberculosis incidence.

Tuberculosis (TB) disease reactivates from distant latent infection or recent (re)infection. Progression risks increase with age. Across the World Health Organisation Western Pacific region, many populations are ageing and have the highest per capita TB incidence rates in older age groups. However, methods for analysing age-specific TB incidence and forecasting epidemic trends while accounting for demographic change remain limited. We applied the Lee-Carter models, which were originally developed for mortality modelling, to model the temporal trends in age-specific TB incidence data from 2005 to 2018 in Taiwan. Females and males were modelled separately. We combined our demographic forecasts, and age-specific TB incidence forecasts to project TB incidence until 2035. We compared TB incidence projections with demography fixed in 2018 to projections accounting for demographic change. Our models quantified increasing incidence rates with age and declining temporal trends. By 2035, the forecast suggests that the TB incidence rate in Taiwan will decrease by 54% (95% Prediction Interval (PI): 45%-59%) compared to 2015, while most age-specific incidence rates will reduce by more than 60%. In 2035, adults aged 65 and above will make up 78% of incident TB cases. Forecast TB incidence in 2035 accounting for demographic change will be 39% (95% PI: 36%-42%) higher than without population ageing. Age-specific incidence forecasts coupled with demographic forecasts can inform the impact of population ageing on TB epidemics. The TB control programme in Taiwan should develop plans specific to older age groups and their care needs.

New ways of estimating excess mortality of chronic diseases from aggregated data: insights from the illness-death model

BackgroundRecently, we have shown that the age-specific prevalence of a disease can be related to the transition rates in the illness-death model via a partial differential equation (PDE). The transition rates are the incidence rate, the remission rate and mortality rates from the ‘Healthy’ and ‘Ill’ states. In case of a chronic disease, we now demonstrate that the PDE can be used to estimate the excess mortality from age-specific prevalence and incidence data. For the prevalence and incidence, aggregated data are sufficient - no individual subject data are needed, which allows application of the methods in contexts of strong data protection or where data from individual subjects is not accessible.MethodsAfter developing novel estimators for the excess mortality derived from the PDE, we apply them to simulated data and compare the findings with the input values of the simulation aiming to evaluate the new approach. In a practical application to claims data from 35 million men insured by the German public health insurance funds, we estimate the population-wide excess mortality of men with diagnosed type 2 diabetes.ResultsIn the simulation study, we find that the estimation of the excess mortality is feasible from prevalence and incidence data if the prevalence is given at two points in time. The accuracy of the method decreases as the temporal difference between these two points in time increases. In our setting, the relative error was 5% and below if the temporal difference was three years or less. Application of the new method to the claims data yields plausible findings for the excess mortality of type 2 diabetes in German men.ConclusionsThe described approach is useful to estimate the excess mortality of a chronic condition from aggregated age-specific incidence and prevalence data.Trial registrationThe article does not report the results of any health care intervention.

Opportunities for improved surveillance and control of dengue from age-specific case data.

One of the challenges faced by global disease surveillance efforts is the lack of comparability across systems. Reporting commonly focuses on overall incidence, despite differences in surveillance quality between and within countries. For most immunizing infections, the age distribution of incident cases provides a more robust picture of trends in transmission. We present a framework to estimate transmission intensity for dengue virus from age-specific incidence data, and apply it to 359 administrative units in Thailand, Colombia, Brazil and Mexico. Our estimates correlate well with those derived from seroprevalence data (the gold standard), capture the expected spatial heterogeneity in risk, and correlate with known environmental drivers of transmission. We show how this approach could be used to guide the implementation of control strategies such as vaccination. Since age-specific counts are routinely collected by masany surveillance systems, they represent a unique opportunity to further our understanding of disease burden and risk for many diseases.

A genetic risk score to personalize prostate cancer screening, applied to population data.

181 Background: Genetic risk stratification may inform the decision of whether—and at what age—a man should undergo prostate cancer (PCa) screening. We previously validated a polygenic hazard score (PHS) for accurate prediction of age of onset of aggressive PCa and for improved screening PSA performance. The PHS is a weighted sum of 54 SNP genotypes. Here, we applied the PHS to population data to assess its potential impact on individualized screening. Methods: Age-specific PCa incidence data were obtained for men aged 40-70 years from the United Kingdom (Cancer Research UK, 2013-2015) and fit to an exponential curve as a continuous model of age-specific PCa incidence. Using hazard ratios estimated from ProtecT study data, annualized incidence rate curves were calculated for the following percentiles of genetic risk: 1, 5, 20, 50, 80, 95, and 99. The proportion of incidence classified as aggressive (Gleason score ≥7) was estimated as 59.7%, the reported result from the CAP trial. PHS was combined with incidence data to give a risk-equivalent age, when a man with given PHS percentile will have the same risk of aggressive PCa as that of a typical man at age 50 years. Results: The age-specific incidence rate of PCa for the UK population was modeled as: 0.004 e0.203(age-40) ( R2 = 0.957, p = 0.001). Table shows risk-equivalent age for each genetic risk percentile. For example, a man with a PHS in the 95th percentile reached PCa risk equivalent to a typical 50-year-old man at age 44 years; conversely, a man with a PHS in the first percentile does not reach this risk level until age 60 years. Initiation of screening discussions could be adjusted accordingly. Conclusions: PHS may inform PCa screening with individualized estimates of risk-equivalent age for aggressive PCa. Risk-equivalent age for aggressive prostate cancer, by PHS percentile. [Table: see text]

2477. Impact of Varicella Vaccination in the United States (US): A Dynamic Model-Based Analysis

BackgroundRoutine childhood immunization with varicella vaccine was first recommended in the United States in 1995 as a 1-dose regimen for children aged 12–18 months, with updated recommendations in 2006 for a 2-dose regimen (first dose at 12–15 months, second dose at 4–6 years). Our objective was to estimate the impact of the US varicella vaccination program.MethodsWe developed a dynamic transmission model to predict the impact on varicella vaccination on health outcomes in the United States. Vaccine coverage rates were extracted from the US National Immunization Survey (NIS); first dose varicella vaccine coverage went from 12% in 1996 to 91% by 2016 for children 18 months old, and second dose coverage starting in 2006 at 5% increasing by 2016 to 94% for children 5 years old; we assumed that 50% of children with no history of vaccination or infection by age 13 would become vaccinated. Interactions between age groups were empirically characterized, and the model was calibrated using age-specific pre-vaccination varicella incidence data.. Vaccine effectiveness was represented via vaccine take and waning immunity estimated from a 10-year trial.ResultsThe model projected reductions of varicella incidence in all ages (and ages <15 years) of 46% (46%) in 2001, 76% (76%) in 2006, 78% (81%) in 2011, and 89% (93%) in 2016 (Figure 1). The projected reductions in varicella cases and varicella-related hospitalizations and deaths for all ages were 74%, 70%, and 66% by 2006 (one-dose era), respectively, increasing to 89%, 70%, and 69% by 2016 (two dose era), respectively (Figure 2). We estimate that between 1996 and 2016, 71,885,382 cases of varicella were prevented in the United States, together with 178,248 varicella-related hospitalizations and 1,496 deaths.ConclusionOur estimates are slightly lower than previously reported US surveillance data which identified a 97.4% (92.9%-97.9%) reduction between 1993–1994 and 2013–2014 in IL, MI, TX, and WV (WER 2016). Likely, this difference is related to under ascertainment of milder cases. This model can be used to estimate the public health benefits of varicella vaccination. The use of a dynamic transmission model does, however, have limitations, including assumptions about age-specific risk and severity of breakthrough disease and the use of a static population. Disclosures L. Wolfson, Merck & Co., Inc.: Employee and Shareholder, Salary. J. Kyle, Merck & Co., Inc.: Independent Contractor, Salary. B. Kuter, Merck: Employee and Shareholder, Salary. M. Levin, Merck Sharp & Dohme Corp.: Scientific Advisor, Consulting fee, Licensing agreement or royalty and Research grant. V. Daniels, Merck & Co., Inc.: Employee and Shareholder, Salary.

Cost-effectiveness of risk-based breast cancer screening programme, China.

ObjectiveTo model the cost–effectiveness of a risk-based breast cancer screening programme in urban China, launched in 2012, compared with no screening.MethodsWe developed a Markov model to estimate the lifetime costs and effects, in terms of quality-adjusted life years (QALYs), of a breast cancer screening programme for high-risk women aged 40–69 years. We derived or adopted age-specific incidence and transition probability data, assuming a natural history progression between the stages of cancer, from other studies. We obtained lifetime direct and indirect treatment costs in 2014 United States dollars (US$) from surveys of breast cancer patients in 37 Chinese hospitals. To calculate QALYs, we derived utility scores from cross-sectional patient surveys. We evaluated incremental cost–effectiveness ratios for various scenarios for comparison with a willingness-to-pay threshold.FindingsOur baseline model of annual screening yielded an incremental cost–effectiveness ratio of US$ 8253/QALY, lower than the willingness-to-pay threshold of US$ 23 050/QALY. One-way and probabilistic sensitivity analyses demonstrated that the results are robust. In the exploration of various scenarios, screening every 3 years is the most cost–effective with an incremental cost–effectiveness ratio of US$ 6671/QALY. The cost–effectiveness of the screening is reduced if not all diagnosed women seek treatment. Finally, the economic benefit of screening women aged 45–69 years with both ultrasound and mammography, compared with mammography alone, is uncertain.ConclusionHigh-risk population-based breast cancer screening is cost–effective compared with no screening.

Case Studies of Gastric, Lung, and Oral Cancer Connect Etiologic Agent Prevalence to Cancer Incidence.

Obtaining detailed individual-level data on both exposure and cancer outcomes is challenging, and it is difficult to understand and characterize how temporal aspects of exposures translate into cancer risk. We show that, in lieu of individual-level information, population-level data on cancer incidence and etiologic agent prevalence can be leveraged to investigate cancer mechanisms and to better characterize and predict cancer trends. We use mechanistic carcinogenesis models [multistage clonal expansion (MSCE) models] and data on smoking, Helicobacter pylori (H. pylori), and HPV infection prevalence to investigate trends of lung, gastric, and HPV-related oropharyngeal cancers. MSCE models are based on the initiation-promotion-malignant conversion paradigm and allow for interpretation of trends in terms of general biological mechanisms. We assumed the rates of initiation depend on the prevalence of the corresponding risk factors. We performed two types of analysis, using the agent prevalence and cancer incidence data to estimate the model parameters and using cancer incidence data to infer the etiologic agent prevalence as well as the model parameters. By including risk factor prevalence, MSCE models with as few as three parameters closely reproduced 40 years of age-specific cancer incidence data. We recovered trends of H. pylori prevalence in the United States and demonstrated that cohort effects can explain the observed bimodal, age-specific pattern of oral HPV prevalence in men. Our results demonstrate the potential for joint analyses of population-level cancer and risk factor data through mechanistic modeling. This approach can be a first step in systematically testing relationships between exposures and cancer risk when individual-level data is lacking.Significance: Analysis of trends in risk-factor prevalence and cancer incidence can shed light on cancer mechanisms and the way that carcinogen exposure through time shapes the risk of cancer at different ages.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/12/3386/F1.large.jpg Cancer Res; 78(12); 3386-96. ©2018 AACR.

Cost-effectiveness and budget impact analyses of a colorectal cancer screening programme in a high adenoma prevalence scenario using MISCAN-Colon microsimulation model

BackgroundThe Basque Colorectal Cancer Screening Programme began in 2009 and the implementation has been complete since 2013. Faecal immunological testing was used for screening in individuals between 50 and 69 years old. Colorectal Cancer in Basque country is characterized by unusual epidemiological features given that Colorectal Cancer incidence is similar to other European countries while adenoma prevalence is higher. The object of our study was to economically evaluate the programme via cost-effectiveness and budget impact analyses with microsimulation models.MethodsWe applied the Microsimulation Screening Analysis (MISCAN)-Colon model to predict trends in Colorectal Cancer incidence and mortality and to quantify the short- and long-term effects and costs of the Basque Colorectal Cancer Screening Programme. The model was calibrated to the Basque demographics in 2008 and age-specific Colorectal Cancer incidence data in the Basque Cancer Registry from 2005 to 2008 before the screening begun. The model was also calibrated to the high adenoma prevalence observed for the Basque population in a previously published study. The multi-cohort approach used in the model included all the cohorts in the programme during 30 years of implementation, with lifetime follow-up. Unit costs were obtained from the Basque Health Service and both cost-effectiveness analysis and budget impact analysis were carried out.ResultsThe goodness-of-fit of the model adaptation to observed programme data was evidence of validation. In the cost-effectiveness analysis, the savings from treatment were larger than the added costs due to screening. Thus, the Basque programme was dominant compared to no screening, as life expectancy increased by 29.3 days per person. The savings in the budget analysis appeared 10 years after the complete implementation of the programme. The average annual budget was €73.4 million from year 2023 onwards.ConclusionsThis economic evaluation showed a screening intervention with a major health gain that also produced net savings when a long follow-up was used to capture the late economic benefit. The number of colonoscopies required was high but remain within the capacity of the Basque Health Service. So far in Europe, no other population Colorectal Cancer screening programme has been evaluated by budget impact analysis.

Parameter estimation for multistage clonal expansion models from cancer incidence data: A practical identifiability analysis.

Many cancers are understood to be the product of multiple somatic mutations or other rate-limiting events. Multistage clonal expansion (MSCE) models are a class of continuous-time Markov chain models that capture the multi-hit initiation–promotion–malignant-conversion hypothesis of carcinogenesis. These models have been used broadly to investigate the epidemiology of many cancers, assess the impact of carcinogen exposures on cancer risk, and evaluate the potential impact of cancer prevention and control strategies on cancer rates. Structural identifiability (the analysis of the maximum parametric information available for a model given perfectly measured data) of certain MSCE models has been previously investigated. However, structural identifiability is a theoretical property and does not address the limitations of real data. In this study, we use pancreatic cancer as a case study to examine the practical identifiability of the two-, three-, and four-stage clonal expansion models given age-specific cancer incidence data using a numerical profile-likelihood approach. We demonstrate that, in the case of the three- and four-stage models, several parameters that are theoretically structurally identifiable, are, in practice, unidentifiable. This result means that key parameters such as the intermediate cell mutation rates are not individually identifiable from the data and that estimation of those parameters, even if structurally identifiable, will not be stable. We also show that products of these practically unidentifiable parameters are practically identifiable, and, based on this, we propose new reparameterizations of the model hazards that resolve the parameter estimation problems. Our results highlight the importance of identifiability to the interpretation of model parameter estimates.

Age-Dependent Metastatic Spread and Survival: Cancer of Unknown Primary as a Model.

In order to describe a novel approach for the clinical study of metastases, we provide here age-specific incidence and survival data for cancer of unknown primary (CUP). Metastases in various organs are found at CUP diagnosis, which have implications for prognosis, and we hypothesize similar prognostic implications for metastases found at diagnosis of primary cancers. We identified 33,224 CUP patients from the Swedish Cancer Registry and calculated incidence rates (IRs) for CUP development. Cox proportional hazards regression models were performed to estimate hazard ratios (HRs) for relative survival in CUP patients compared to the general population. In age-group specific analyses, a maximal IR was reached at age 85–89 years, followed by a marked decline to age 90+ (7-fold in men and 3-fold in women). The overall HR for relative survival declined systematically by age. CUP may be applied as an epidemiological age-incidence model for cancer metastases providing evidence in line with autopsy data that the metastatic potential, as shown by the incidence of CUP, appears to weaken markedly at age 85 years, depending on metastatic locations. The relative death rates were highest among young patients, which was probably entirely due to the low death rates in young background population.

Acute lymphoblastic leukemia: an assessment of international incidence, survival, and disease burden

Acute lymphoblastic leukemia (ALL) is a rare hematological malignancy. With the recent introduction of a classification system for hematopoietic and lymphoid neoplasms, more comprehensive assessment of ALL epidemiology is now possible. In this study, we describe recent international incidence of ALL and project the annual number of diagnoses to 2025. We also estimate relative survival and average potential years of life lost (AYLL) to assess the societal burden of ALL. Age-specific incidence data for ALL from select cancer registries in different geographies were obtained from the International Agency for Research on Cancer's Cancer Incidence in Five Continents Database. Country-specific age-standardized rates were calculated to allow for direct comparisons between countries. ALL-specific mortality and relative survival data were only available from the United States (US) National Cancer Institute's Surveillance, Epidemiology, and End Results program; mortality rates were estimated for other countries. The age-standardized incidence rate of ALL during 2003-2007 ranged from 1.08 to 2.12 per 100,000 person-years in selected countries. Incidence was generally higher in the Americas and Oceania and lower in Asia and Eastern Europe. In most countries, the incidence rate of ALL in children was approximately four times that in adults. Survival was particularly poor among adults. In selected countries, the estimated AYLL ranged from 30 to 48 years for all ages and from 23 to 39 years for adults. Although a rare disease, ALL presents a significant public health burden given poor survival outcomes among adults, AYLL, and its importance as the most common pediatric cancer.

Impact of tetanus, diphtheria, and acellular pertussis (Tdap) vaccine use in wound management on health care costs and pertussis cases.

The Advisory Committee on Immunization Practices (ACIP) recommends the use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine for routine wound management in adolescents and adults who require a tetanus toxoid-containing vaccine who were vaccinated ≥ 5 years earlier with tetanus toxoid, reduced diphtheria toxoid (Td) vaccine, and who have not previously received Tdap. To estimate the overall budget and health impact of vaccinating individuals presenting for wound management with Tdap instead of Td vaccine, the current standard of care in practices that do not use Tdap for purposes of wound management. A decision-analytic economic model was developed to estimate the expected increase in direct medical costs and the expected number of cases of pertussis avoided associated with the use of Tdap instead of Td vaccine in the wound management setting. Patients eligible for Tdap were aged 10+ years and required a tetanus-containing vaccine. Age-specific wound incidence data and Td and Tdap vaccination rates were taken from the National Health Interview Survey and the National Immunization Survey for the most recent available year. Age-specific pertussis incidence used in this analysis (151 per 100,000 for adolescents, 366 per 100,000 for those aged 20-64 years, and 176 per 100,000 for those aged 65+ years) used reported incidence rates adjusted by a factor of 10 for adolescents and by a factor of 100 for adults, based on assumptions previously made by ACIP to account for underreporting. Vaccine wholesale acquisition costs without federal excise tax were assumed in the base case. Efficacy of vaccination with Tdap in preventing pertussis was based on clinical trial data. Possible herd immunity effects of vaccination were not included in the model. Costs associated with vaccination and treatment of pertussis cases were reported as total annual costs and per-member-per-month (PMPM) costs for hypothetical health plans and for the U.S. population. Aggregate and incremental costs and pertussis cases avoided were presented undiscounted (as recommended for budget-impact analyses) annually and cumulatively over a 3-year time horizon in 2012 U.S. dollars. Scenario analyses were conducted on key parameters, including wound incidence, pertussis incidence, vaccine efficacy and waning protection against pertussis, uptake rates for Tdap, and vaccine prices using alternative data sources or alternative clinically relevant assumptions. For a health plan with 1 million covered lives aged < 65 years, vaccination with Tdap instead of Td was estimated to cost an additional $132,364 ($0.01 PMPM) in the first year and an additional $368,640 ($0.01 PMPM) cumulatively over 3 years. For a health plan with 1 million covered lives aged 65+ years, vaccination with Tdap instead of Td was estimated to cost an additional $201,165 ($0.02 PMPM) in the first year and an additional $549,568 ($0.02 PMPM) cumulatively over 3 years. For the U.S. population aged 10+ years, vaccination with Tdap instead of Td was estimated to result in protection against pertussis for an additional 2.7 million patients with wounds annually and was estimated to cost an additional $121,101,671 to avoid 42,104 cases of pertussis over the 3-year time horizon. Results were sensitive to input parameter values, particularly parameters associated with the number of patients with wounds vaccinated with Tdap (range 2.7 to 5.1 million patients). However, for all of the alternative scenarios tested, the expected increase in PMPM costs ranged from < $0.01 to $0.03. Vaccination of adolescents and adults with Tdap for wound management may result in an increase in PMPM costs for health plans of < $0.01 to $0.03. Given the potential reduction in pertussis cases at the population level, vaccination with Tdap for routine wound management could be considered as another strategy to help address the pertussis public health concern in the United States.

Incidence of nonmelanoma skin cancer in relation to ambient UV radiation in white populations, 1978-2012: empirical relationships.

Nonmelanoma skin cancers (NMSCs) are the most common cancers in fair-skinned populations. Their incidence continues to increase in many countries. Exposure to UV radiation (UVR) is the primary cause of NMSC, although the pattern of exposure that gives rise to different types of NMSC appears to vary. To examine dose-response relationships between ambient UVR levels and NMSC incidence at the population level. Peer-reviewed literature published from January 1, 1978, through December 31, 2012, that provided age- and sex-specific incidence of NMSC in white populations worldwide was systematically reviewed. Mean erythemally weighted daily ambient UVR levels for each study location were derived from satellite data. The incidence of NMSC in white populations worldwide as reported in population-based studies. Forty eligible publications were included in the analysis. Analysis models that contained age group, sex, study year, mean daily UVR, and day-to-day variability of UVR explained most of the variability in NMSC incidence: 82% for basal cell carcinoma (BCC) and 85% for squamous cell carcinoma (SCC). Exclusion of studies in which imputation of age-specific incidence data from standardized rates was required improved the model fit to 85% for BCC and 88% for SCC. Higher mean daily UVR was associated with higher NMSC incidence rates; this was greater in men than women for BCC (70% vs 60%) but greater in women for SCC (99% vs 92%). Incidence rates for BCC and SCC were higher among those older than 60 years, but the increase with age was steeper for those younger than 60 years. Our models highlight the etiologic differences between BCC and SCC and allow prediction of NMSC incidence for data-poor regions and under changing demographic and environmental conditions.

Estimated public health impact of nationwide vaccination of infants with 7-valent pneumococcal conjugate vaccine (PCV7) in China

The goal of this study was to provide a comprehensive analysis of the potential health impact of universal vaccination of infants with the 7-valent pneumococcal conjugate vaccine (PCV7) in China. A decision-analytic model designed for pneumococcal disease and outcomes of pneumococcal infection was populated with local age-specific incidence and mortality data to estimate the expected health benefits of vaccinating birth cohorts of approximately 16 million infants per year over a 10-year time horizon in China. The model incorporates both the direct impact on vaccinated children and the indirect effect of herd protection on unvaccinated children and adults. The model predicts that more than 16.2 million cases of pneumococcal disease and 709 411 deaths could be prevented in China over the initial 10-year period following the introduction of the PCV7 vaccine. The majority of these health benefits are due to the indirect effectiveness of the vaccine on the unvaccinated population, resulting in approximately 10.8 million cases prevented and 636 371 lives saved over 10 years. The results suggest that a policy of universal PCV7 vaccination among infants in China would have a substantial positive public health impact on the population of China.