Population-based Open Cohort Study Research Articles

Evaluating mammography screening in observational cohort designs: the importance of avoiding lead time bias.

To investigate the potential lead time bias of the evaluation model (extended follow-up for women diagnosed with breast cancer) used to evaluate mammography screening in a recent Danish study. This model was compared with two traditional models. We retrieved data on women diagnosed with breast cancer in each county of Norway from 1986 to 2016. In a population-based open cohort study, the change in incidence-based mortality (IBM) was estimated by relative rate ratios comparing a screening period with a historical period for each of three age groups: women eligible for screening and younger and older ineligible women. We applied the evaluation model, and for comparison two traditional IBM models from a recent Norwegian study: one without extended follow-up and no possibility of lead time bias and one with extended follow-up irrespective of diagnosis, possibly diluting any screening effect. The evaluation model estimated an extra 11% reduction in breast cancer mortality among the screening eligible relative to ineligible women. However, this result could largely be ascribed to lead time bias inflated by overdiagnosis and a decreasing mortality from other causes among eligible women. A reduction in breast cancer mortality was observed for both eligible and younger and older ineligible women across models, and relative rate ratios close to 1 were obtained using the two traditional IBM models, indicating no effect of screening on breast cancer mortality. Two models without lead time bias found no reduction in breast cancer mortality, whereas the evaluation model estimated a reduction attributable to lead time bias.

Population dynamics of HIV drug resistance during treatment scale-up in Uganda: a population-based longitudinal study.

Clinical studies have reported rising pre-treatment HIV drug resistance during antiretroviral treatment (ART) scale-up in Africa, but representative data are limited. We estimated population-level drug resistance trends during ART expansion in Uganda. We analyzed data from the population-based open Rakai Community Cohort Study conducted at agrarian, trading, and fishing communities in southern Uganda between 2012 and 2019. Consenting participants aged 15-49 were HIV tested and completed questionnaires. Persons living with HIV (PLHIV) provided samples for viral load quantification and virus deep-sequencing. Sequence data were used to predict resistance. Population prevalence of class-specific resistance and resistance-conferring substitutions were estimated using robust log-Poisson regression. Data from 93,622 participant-visits, including 4,702 deep-sequencing measurements, showed that the prevalence of NNRTI resistance among pre-treatment viremic PLHIV doubled between 2012 and 2017 (PR:1.98, 95%CI:1.34-2.91), rising to 9.61% (7.27-12.7%). The overall population prevalence of pre-treatment viremic NNRTI and NRTI resistance among all participants decreased during the same period, reaching 0.25% (0.18% - 0.33%) and 0.05% (0.02% - 0.10%), respectively ( p- values for trend = 0.00015, 0.002), coincident with increasing treatment coverage and viral suppression. By the final survey, population prevalence of resistance contributed by treatment-experienced PLHIV exceeded that from pre-treatment PLHIV, with NNRTI resistance at 0.54% (0.44%-0.66%) and NRTI resistance at 0.42% (0.33% - 0.53%). Overall, NNRTI and NRTI resistance was predominantly attributable to rtK103N and rtM184V. While 10.52% (7.97%-13.87%) and 9.95% (6.41%-15.43%) of viremic pre-treatment and treatment-experienced PLHIV harbored the inT97A mutation, no major dolutegravir resistance mutations were observed. Despite rising NNRTI resistance among pre-treatment PLHIV, overall population prevalence of pre-treatment resistance decreased due to treatment uptake. Most NNRTI and NRTI resistance is now contributed by treatment-experienced PLHIV. The high prevalence of mutations conferring resistance to components of current first-line ART regimens among PLHIV with viremia is potentially concerning. National Institutes of Health and the Gates Foundation. Evidence before the study: We searched PubMed for studies matching the keywords "hiv" "resistance" "longitudinal" "cohort" "population" published since 2004 (the beginning of antiretroviral therapy (ART) availability in sub-Saharan Africa) and identified 50 studies. We excluded 34 studies not based in sub-Saharan Africa, five studies primarily concerned with infection with other pathogens (e.g. HBV, M. tuberculosis ), two studies concerned with insulin resistance, one sequencing-methods paper, and one paper concerned with host susceptibility to HIV infection. The remaining seven studies were not population-based meaning that the study population was not all persons but e.g. people living with HIV enrolled in care at a given clinic. Population-based cohort are essential for monitoring HIV drug resistance in both treated and untreated individuals, including those people who may go undetected in clinical settings, capturing evolutionary dynamics of resistance in real-world conditions. Added value of this study: We estimated the prevalence of drug resistance over five consecutive survey rounds of a population-based open-cohort study in southern Uganda between 2012 and 2019 during a period of intense treatment scale-up. We show that among the entire population regardless of HIV status, 0.8% and 0.5% of individuals harbor viremic resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside-reverse transcriptase inhibitors (NRTIs), respectively, of which the majority is dual-class NNRTI/NRTI resistance. Despite a two-fold increase in the prevalence of NNRTI resistance among pre-treatment viremic PLHIV, the overall prevalence of pre-treatment viremic resistance in the entire population decreased by more than 50% due to increased treatment initiation and population viral load suppression. The majority of resistance in recent survey rounds was contributed by treatment-experienced PLHIV. Among treatment-experienced viremic PLHIV, we observe a substantial burden of mutations that confer resistance to the NNRTI and NRTI components of dolutegravir and cabotegravir based regimens e.g. rtM184V (34%) rtY181C (15%), rtG190A (12%), rtK65R (12%), and rtK101E (9.5%). The integrase strand transfer inhibitor (INSTI) resistance mutation inT97A was observed in about a tenth of viremic PLHIV.These results provide the first longitudinal population-based estimates of temporal trends in the prevalence of drug resistance during ART program expansion in a high-burden setting. Further, they provide critical insight into the landscape of prevalent drug resistance substitutions circulating in this population.Implications of all the available evidence: Scale-up of HIV treatment has increased the prevalence of drug resistance mutations among viremic people living with HIV in sub-Saharan Africa. The relatively high prevalence of NNRTI resistance has prompted a recent shift to first-line regimens including dolutegravir (an INSTI) in combination with NRTIs. The high prevalence of mutations conferring resistance to components of current first-line regimens in our population warrants continued monitoring of treatment failures and the prevalence of drug resistance in high burden settings.

Incidence of Dermatitis Herpetiformis in Sweden 2005 to 2018: A Nationwide Retrospective Cohort Study.

Dermatitis herpetiformis has been investigated in the past; however, only a limited number of studies have reported its incidence based on validated nationwide population-based registries. To address this gap, the aims of this study are to estimate the incidence of dermatitis herpetiformis in Sweden and to validate the National Patient Register (NPR) for diagnosis of dermatitis herpetiformis. A population-based open cohort study was conducted, including all patients diagnosed with dermatitis herpetiformis (International Classification of Diseases 10th revision; ICD-10 code L13.0) in Sweden from 2005 to 2018 (n = 1,724), identified from the NPR. The diagnosis of dermatitis herpetiformis in the NPR was validated using medical records, histopathological and immunopathological data, yielding a positive predictive value (PPV) of 62.5%. The mean annual incidence of dermatitis herpetiformis was 0.93/100,000 (95% confidence interval 0.79-1.08), female to male ratio 1:1, and mean age at diagnosis 60.9 years. In conclusion, this large nationwide cohort study showed a low validity for diagnosis of dermatitis herpetiformis in the NPR, and the adjusted incidence rate of dermatitis herpetiformis in Sweden was estimated to be 0.93/100,000, which is lower than that in previous Swedish studies.

Association between thyroid function, nursing home admission and mortality in community-dwelling adults over 80 years

PurposeThyroid deficiency may reduce mortality in older adults, but older adults prioritize independence over merely staying alive. We investigated the association between thyroid dysfunction and nursing home admission and all-cause mortality in community-dwelling older adults over 80. MethodsWe conducted a retrospective population-based open cohort study using data from laboratory registries covering 75% of Denmark supplemented by national registries. We included all community-dwelling older adults over 80 years with a first TSH measurement between 1996 and 2019. Participants with prior thyroid disorders or medication affecting the thyroid were excluded. Participants were followed from inclusion until nursing home admission, death or loss to follow-up due to emigration. ResultsWe included 272,495 participants at baseline. Median follow-time was 3.71 years in analyses of nursing home admissions and 4.00 years for all-cause mortality. Hypothyroidism was associated with lower nursing home admission (TSH 5–10 mIU/l: HR 0.85, 95% CI: 0.80–0.91, P < 0.001); TSH >10 mIU/l HR 0.68, 95% CI: 0.54–0.85, P = 0.001) and with reduced all-cause mortality (TSH >10 mIU/l: HR 0.81, 95% CI: 0.70–0.93, P = 0.002). The association between hyperthyroidism and nursing home admission was of little clinical significance while hyperthyroidism was associated with increased all-cause mortality hazard both for low (HR 1.16, 95% CI 1.13–1.19, P < 0.001) and suppressed (HR 95% CI: 1.14 1.07–1.21, P < 0.001) TSH. Conclusion: Hypothyroidism is associated with a reduced nursing home admission hazard and to a lesser extent all-cause mortality in community-dwelling adults over 80 years, while hyperthyroidism is associated with increased all-cause mortality but not hazard of nursing home admission.

Cohort profile: the Mâncio Lima cohort study of urban malaria in Amazonian Brazil

PurposeThis population-based open cohort study aims to investigate biological and sociodemographic drivers of malaria transmission in the main urban hotspot of Amazonian Brazil.ParticipantsNearly 20% of the households in the northwestern...

Did Emergency Department Visits in Infants and Young Children Increase in the Last Decade?: An Ontario, Canada Study.

The aims of the study were to measure overall trends and to identify leading causes for pediatric emergency department (ED) visits among children aged 0 to 4 years. We conducted an 11-year population-based open cohort study using health administrative data from 2008 to 2018 in Ontario, Canada. All ED visits were extracted from the National Ambulatory Care Reporting System, along with the most responsible cause of each visit. Annual ED visit rates were calculated per 100 children in each year. Overall and disease-specific rates for all children were calculated and then stratified by sex and age groups. Relative percentage change in rates between 2008 and 2018 were calculated and compared using standardized differences (SDIFs). Statistical significance of time trends was tested using Poisson regression. This study included an average of 911,566 children from 2008 to 2018. All-cause ED visit rates increased by 28.2% from 2008 to 2018 (43.24-55.42 per 100, SDIF >0.1). Respiratory diseases were consistently the top cause of ED visits, and contributed to 1 in 3 ED visits in 2018. These respiratory conditions include asthma, asthma-related diseases (bronchiolitis, bronchitis, influenza, and pneumonia), and other respiratory diseases. Respiratory ED visit rates increased by 32.8% from 2008 to 2018 (11.51-15.28 per 100, SDIF <0.1), driven by a 46.4% (14.58-21.35 per 100, SDIF >0.1) increase among children younger than 1 year. There was a 78.0% increase in ED visits for bronchiolitis in infants (1.45-2.58 per 100, SDIF <0.1). Respiratory diseases like bronchiolitis among infants were the consistent leading cause for ED visits. All-cause ED visit rates among young children increased by 28.17% from 2008 to 2018.

Exposure to ultrafine particles and the incidence of asthma in children: A population-based open cohort study in Montreal, Canada

BACKGROUND AND AIM: Asthma is the most prevalent chronic respiratory disease in children and represents an important burden on health care systems. The association between air pollution and asthma is well established, however the role of ultrafine particles (UFPs) remains unclear. We evaluated the association between long-term exposure to UFPs and childhood-onset asthma in a population-based birth cohort in Montreal, Canada. METHODS: The cohort was constructed from the Quebec Integrated Chronic Disease Surveillance System and included all children born in Quebec between 2000 and 2015 who were resident of Montreal. Case definitions consisted of at least two physician claims with a diagnosis of asthma within a two-year period or one hospital discharge with a primary or secondary diagnosis of asthma. Annual concentrations of UFPs and of nitrogen dioxide (NO2) were estimated from land use regression models developed for Montreal and assigned at participants’ residence over the follow-up using their residential postal codes. The association between UFPs and childhood asthma onset was estimated with a Cox proportional hazards model stratified for sex and adjusted for age, neighbourhood material and social deprivation, calendar year and co-exposure to NO2. RESULTS:The cohort included 352,966 children, with 30,825 incident asthma cases. The annual average concentrations were 24,427 particles/cm3 for UFPs and 18.55 ppb for NO2. In the single pollutant model, the adjusted hazard ratio (HR) per interquartile range (IQR) increase in UFPs was 0.990 (95% CI: 0.983, 0.997). The two-pollutant model showed no association for UFPs (HR per IQR = 0.986; 95% CI: 0.979, 0.997) but a positive association for NO2 (HR per IQR = 1.038; 95% CI: 1.013, 1.051). CONCLUSIONS:In this population-based birth cohort, childhood asthma onset was not associated with UFPs but positively associated with NO2 estimated at participants’ residential location. KEYWORDS: Air pollution, Particulate matter, Asthma, Respiratory outcomes, Children's environmental health

Long-term air pollution exposure and incident stroke in American elderly population: a national cohort study

BACKGROUND AND AIM: Literature has linked air pollution and cerebrovascular diseases including stroke. However, evidence is limited for the simultaneous effects of multiple air pollutants on stroke incidence. METHODS: A nationwide population-based open cohort study was used to estimate the association between long-term exposure to PM2.5, NO2, ozone, and stroke incidence. The study population included all free-for-service Medicare enrollees (aged ≥65 years) in the contiguous United States from 2000-2017. We estimated the hazard ratios (HRs) for the first diagnosis with stroke using single-, bi-, and tri-pollutant Cox proportional hazards models that controlled for demographic characteristics, Medicaid eligibility, and area-level covariates. We further looked at this relationship in two sub-cohorts of enrollees who were always exposed to pollutant levels below the US EPA National Ambient Air Quality Standards [NAAQS] (annual PM2.5 ≤12 μg/m³, annual NO2 ≤53 ppb, and warm-season ozone ≤50 ppb) and the WHO air quality guideline (annual PM2.5 ≤10 μg/m³, annual NO2 ≤20 ppb, and warm-season ozone ≤40 ppb). RESULTS:Increases of 10 μg/m³ in PM2.5, 10 ppb in NO2, and 10 ppb in ozone were associated with increased risk of first diagnosis with stroke, with HRs of 1.063 (95% CI, 1.048-1.077), 1.048 (1.043-1.052), and 1.031 (1.026-1.037), respectively. Among the below EPA low-exposure sub-cohort, the corresponding HRs were 1.041 (95% CI, 1.008-1.075), 1.067 (1.056-1.077), and 1.123 (1.108-1.138), respectively. When restricting analyses to levels below the WHO air quality guidelines, increasing pollution levels were consistently associated with a greater hazard estimate. CONCLUSIONS:Long-term exposure to air pollution, even at concentrations below NAAQS or international standards, was significantly associated with increased stroke incidence among the US elderly population. KEYWORDS: Air pollution, Multi-pollutant, Stroke

Association between chronic obstructive pulmonary disease and long-term ozone and PM2.5 exposure among Medicare participants: a national cohort study

BACKGROUND AND AIM: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally and both ozone and PM2.5 exposures are main risk factors. However, few studies have investigated the association of long-term ambient ozone exposure with respiratory morbidity and its simultaneous effect with PM2.5. METHODS: A nationwide population-based open cohort study was used to estimate the association between long-term exposure to ambient ozone, PM2.5 and COPD incidence. The study population included all Medicare enrollees (aged ≥65 years) who were always enrolled in Medicare free-for-service program and in both Medicare Part A (hospital insurance) and Part B (medical insurance) in the contiguous United States from 2000-2016. We estimated the hazard ratios (HRs) for the first diagnosis with COPD using single- and co-pollutant Cox proportional hazards models that controlled for demographic characteristics, Medicaid eligibility, and area-level covariates. We further looked at this relationship at lower pollutant concentrations, restricting Medicare enrollees who were always exposed to pollutant levels below the US EPA National Ambient Air Quality Standards [NAAQS] (annual PM2.5 ≤12 μg/m³ and warm-season ozone ≤50 ppb), and among potentially susceptible subgroups. RESULTS:Among the full cohort of 18.9 million enrollees, increases of 10 ppb in annual warm-season ozone and 10 μg/m³ in annual PM2.5 were associated with increased risk of first diagnosis with COPD, with HRs of 1.048 (1.039-1.057) and 1.054 (95% CI, 1.036-1.072) in the co-pollutant model, respectively. When restricting analyses to the below EPA low-exposure sub-cohort (9.6-million enrollees), the corresponding HRs were 1.160 (1.142-1.178) for exposure to ozone and 1.109 (95% CI, 1.068-1.151) for exposure to PM2.5. CONCLUSIONS:Both long-term ozone and PM2.5 exposures were associated with increased risk of COPD incidence among the US elderly population, even at concentrations below the current NAAQS standards. KEYWORDS: Air pollution, Multi-pollution, Chronic obstructive pulmonary disease

Effect of smoke-free legislation on respiratory health services use in children with asthma: a population-based open cohort study in Ontario, Canada

ObjectiveThis study will add to existing literature by examining the impact of smoke-free legislation in outdoor areas among children with asthma. We aimed to examine the effect of the 2015...

Twinship and Childhood Atopic Disease: Understanding Early-Life Factors Among Discordant Twins in Ontario, Canada

Background: Parents often question why one of their children have asthma while their siblings do not. With twins, this is especially perplexing. The gene-environment interaction hypothesis suggests that early-life environmental exposures interact with genes, leading to asthma and atopic diseases. This study aims to investigate potential risk factors that modifies the risk of asthma and other atopic diseases between twins in shared early-life environments. Methods: A paired population-based open cohort study was conducted using health administrative data between April 1, 2004 and March 31, 2019 from Ontario, Canada. The study population consisted of Ontario twins born between 2004-2017. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for associations between discordance (asthma, allergic rhinitis, and eczema) and early-life factors. Results: This study included 24,392 twin-pairs from Ontario Canada aged 1 to 15 years. 15·7%, 17·9%, and 31·9% of twin-pairs had discordant asthma, allergic rhinitis, and eczema respectively. Compared to female-female twin-pairs, male-female and male-male twin-pairs were 69% (95% CI: 1·54-1·84) and 35% (95% CI: 1·23-1·49) higher odds to have asthma discordance, respectively. Twins who were delivered by Caesarian-section had significantly higher odds of asthma (aOR: 1·09, 95% CI: 1·01-1·18) and allergic rhinitis (aOR: 1·11, 95% CI: 1·04-1·20), and is strongly suggested for eczema discordance (aOR: 1·05, 95% CI: 1·00-1·12), compared to pairs who had vaginal births. Conclusion: This population-based study found associations of various early-life factors and asthma and allergic diseases discordance between twins. While early-life factors were associated with disease risks in children, genetic factors played a strong underlying role. Funding: This study was funded by the Asthma and COPD Program, Ontario Ministry of Health and Long-Term Care (MOHLTC). Declaration of Interest: None to declare. Ethical Approval: Ethics approval for this study was obtained from the Hospital for Sick Children Research Ethics Board in Toronto, Ontario.

Association of Income With the Incidence Rates of First Psychiatric Hospital Admissions in Finland, 1996-2014

The association between income and mental health has long been a question of interest. Nationwide register data provide means to examine trends and patterns of these associations. To compare income-specific trends in the incidence rates of first psychiatric hospital admissions and to evaluate whether an income gradient exists in the incidence rates at all levels of household income. This population-based open cohort study used linked registry data from nationwide Finnish Hospital Discharge and Statistics Finland population registers to determine annual incidence rates of first psychiatric hospital admissions. All Finnish citizens (N = 6 258 033) living in the country at any time from January 1, 1996, through December 31, 2014, contributed to 96 184 614 person-years at risk of first inpatient treatment for mental disorders. The analyses were conducted from August 1, 2018, through September 30, 2019. Equivalized disposable income, sex, age group, reduction in income decile in the previous 3 years, urbanicity, educational level, and living alone status. Annual percentage changes in the age-standardized incidence rates and incidence rate ratios (IRRs). Altogether, 186 082 first psychiatric inpatient treatment episodes occurred (93 431 [50.2%] men), with overall age-standardized incidence rates per 1000 person-years varying from 1.59 (95% CI, 1.56-1.63) in 2014 to 2.11 (95% CI, 2.07-2.15) in 2008. In the highest income deciles, a continuous mean decrease per year of 3.71% (95% CI, 2.82%-4.59%) in men and 0.91% (95% CI, 0.01%-1.80%) in women occurred throughout the study period, in contrast to the lowest deciles, where the trends first increased (1.31% [95% CI, 0.62%-2.01%] increase in men from 1996 to 2007 and 5.61% [95% CI, 2.36%-8.96%] increase in women from 1996 to 2001). In the adult population, an income gradient was observed at all levels of household income: the lower the income decile, the higher the adjusted IRRs compared with the highest decile. The IRRs in the lowest decile varied from 2.94 (95% CI, 2.78-3.11) to 4.46 (95% CI, 4.17-4.76). In other age groups, the gradient did not persist at the highest income deciles. Diagnosis-specific income gradient was steepest in schizophrenia and related psychotic disorders, with estimated IRRs of the lowest income decile of 5.89 (95% CI, 5.77-6.02). In this cohort study, clear negative income gradient in the incidence rates of first hospital-treated mental disorders was observed in the adult population of Finland. These findings suggest that reduction in the use of inpatient care has not taken place equally between different income groups.

Intimate partner violence, HIV and sexually transmitted infections in fishing, trading and agrarian communities in Rakai, Uganda

BackgroundIntimate partner violence (IPV), HIV and sexually transmitted infections (STI) can contribute to disparities in population health, depending on the individual, social and environmental factors characterizing a setting. To better understand the place-based determinants and patterns of these key interrelated public health problems in Uganda, we compared risk factors for IPV, HIV and STI in fishing, trading and agrarian communities in Rakai, Uganda by gender.MethodThis study used cross-sectional data collected from 14,464 sexually active men (n = 6531) and women (n = 7933) as part of the Rakai Community Cohort Study, a population-based open cohort study of men and women aged 15–49 years. We used multilevel modified poisson regression models, which incorporated random intercepts for community and households. Factors associated with IPV, HIV and STI were assessed separately for men and women in fishing, trading and agrarian communities.ResultsA larger proportion of participants in the fishing communities than those in trading and agrarian communities were HIV positive, engaged in HIV risk behaviors, had STI symptoms and reported perpetration of or victimization by IPV. Female gender was a shared correlate of IPV, HIV and STI in the fishing communities. Engagement in multiple sexual relationships or partner’s engagement in multiple relationships were shared correlates of IPV, and HIV in agrarian communities and IPV and STI in trading communities.ConclusionPrograms should target factors at multiple levels to reduce risk for syndemic conditions of HIV, STI and IPV in Rakai, Uganda particularly among men and women in fishing communities.

Educational inequalities in fracture-related mortality using multiple cause of death data in the Skåne region, Sweden.

Aim: To assess the absolute and relative educational inequalities in mortality from hip and non-hip fractures in Skåne region, Sweden. Methods: We conducted a population-based open cohort study. People aged 30-99 years, resident in the region during 1998-2013 (n = 999, 148) were followed until death, their 100th birthday, relocation outside Skåne, or the end of 2014. We obtained individual-level data from the Statistics Sweden and the Swedish National Board of Health and Welfare's Cause of Death Register. Death certificates coded with any fracture diagnosis were defined as fracture-related deaths. Educational inequalities were assessed by slope and relative indices of inequality (SII and RII). Cox regression and additive hazard models were used to estimates these indices. Results: During a mean follow-up of 12.2 years, there were 5,121 fracture-related deaths, of which 3,110 were associated with hip fracture. Age-standardized, hip fracture-related mortality rates per 100,000 person-years were 31, 95% confidence interval (CI) (30, 32) and 23 (20, 26) in people with low and high levels of education, respectively (rate ratio 1.4, 95% CI (1.2, 1.5)). Corresponding mortality rates for non-hip-fracture related deaths were 20 (18, 21) and 16 (14, 19) (rate ratio 1.2, 95% CI (1.0, 1.4)). SII and RII revealed educational inequalities in hip fracture-related mortality in favour of highly educated people. For non hip fracture-related mortality, there were statistically significant educational inequalities in people aged <70 years. Conclusions: We found higher fracture-related mortality with lower education suggesting preventative and therapeutic interventions for fractures should pay special attention to people with low-level education.

Incidence of bullous pemphigoid in Sweden 2005\u20132012: a nationwide population-based cohort study of 3761 patients

Studies that report the incidence of bullous pemphigoid from validated nationwide population-based registries are rare. The aim of this study was to estimate the incidence of bullous pemphigoid in Sweden 2005–2012. A population-based open cohort study was designed including all patients diagnosed by a dermatologist with bullous pemphigoid (BP) in Sweden from 2005 to 2012 (n = 3761), identified from the National Patient Register (NPR). The diagnosis of bullous pemphigoid in the NPR was recently validated from medical records, histopathological and immunopathological data by our group in a previous study. The average annual incidence of bullous pemphigoid was 7.1/100,000 (95% CI 6.5–7.7). Female to male ratio was 1.2:1, mean age at diagnosis was 78.9 years. The age-specific incidence rate increased markedly after 80 years of age with an incidence peak between 90 and 99 years of age, 81.9/100,000 (95% CI 75.0–89.2). This large nationwide cohort study presents an adjusted incidence of BP of 7.1/100,000 (95% CI 6.5–7.7) in Sweden. The incidence of bullous pemphigoid is higher than expected and bullous pemphigoid is a common disease in the elderly population.

Socioeconomic position and incidence of colorectal cancer in the Swedish population

BackgroundThe association between socioeconomic position and incidence of colorectal cancer is inconsistent and differs by global region. We aimed to clarify this association in the Swedish population. MethodsWe conducted a population-based open cohort study using data from Swedish national registers. We included all individuals, aged ≥30 years, residing in Sweden between 1993 and 2010. Socioeconomic position was indicated by (1) highest educational level (five groups), and (2) disposable income (quintiles). We used Poisson regression to estimate incidence rate ratios (IRR) and 95% confidence intervals (95% CI) of colon and rectal cancer, and colon and rectal dysplasia. ResultsIn total, 97,827,817 person-years were accumulated and 82,686 cases of colorectal cancer were diagnosed. Compared to men with ‘higher secondary’ education, the adjusted IRRs (95% CI) of rectal cancer in men with ‘primary or less’, ‘lower secondary’, ‘lower university’ or ‘higher university’ education were: 1.06 (1.00, 1.11), 1.05 (0.99, 1.10), 0.96 (0.89, 1.03), and 0.92 (0.86, 0.98), respectively. In women, the corresponding figures were: 1.04 (0.95, 1.14), 1.03 (0.94, 1.13), 0.92 (0.82, 1.02) and 0.92 (0.82, 1.02). Disposable income was not associated with rectal cancer incidence. Adjusted IRRs of colon cancer did not differ between levels of education or disposable income overall or for specific colon sub-sites. Neither education nor disposable income was consistently associated with incidence of colon or rectal dysplasia. ConclusionsPrevention strategies for colon cancer should be applicable to individuals regardless of their socioeconomic position. However, factors conferred by education, e.g., health awareness, may be important for approaches aiming to reduce inequalities in incidence of rectal cancer. Further evaluation of cancer prevention and health promotion strategies among less educated groups is warranted.

Adult life expectancy trends in the era of antiretroviral treatment in rural Uganda (1991-2012).

To estimate the impact of antiretroviral therapy (ART) on population-wide adult life expectancy. A population-based open cohort study with repeated HIV status measurements and registration of vital events in Southwestern Uganda (1991-2012). Nonparametric survival analysis techniques are used for estimating trends in the adult life expectancy of the general population (aged 15 and above), the adult life expectancy by HIV status, and the adult life expectancy deficit. The life expectancy deficit is estimated as the difference between overall life expectancy and life expectancy of the HIV-negative population. All estimates are disaggregated by sex. Between 1991-1993 and 2009-2012, population-wide adult life expectancy increased from 39.3 [95% confidence interval (CI): 35.9-42.8] to 56.1 years (95% CI: 54.0-58.5) in women, and from 38.6 (95% CI: 35.4-42.1) to 51.4 years (95% CI: 49.2-53.7) in men. Most of the adult life expectancy gains coincide with the introduction of ART in 2004; as evidenced by an increase in the adult life expectancy of people living with HIV between 2000-2002 and 2009-2012 of 22.9 and 20.0 years for women and men, respectively. Over the whole period of observation, the adult life expectancy deficit associated with HIV decreased from 16.1 (95% CI: 12.7-19.8) to 6.0 years (95% CI: 4.1-7.8) among women, and from 16.0 (95% CI: 12.1-19.9) to 2.8 years (95% CI: 1.2-4.6) among men. Population-wide life expectancy increased substantially, largely driven by reductions in HIV-related mortality. Women have gained more adult life years than men since the introduction of ART, but the burden of HIV in terms of the life years lost is still larger for women than it is for men.

Participation in four rounds of a French colorectal cancer screening programme with guaiac faecal occult blood test: a population-based open cohort study.

Four randomized controlled trials have demonstrated the efficacy of screening using a guaiac faecal occult blood test (gFOBT) on colorectal cancer (CRC) mortality. Whether their results are transposable to the real world is unknown. This study aimed to assess the determinants of participation in the first four rounds of the CRC screening programme using a gFOBT implemented since 2003 in the Haut-Rhin (Alsace) part of the French national programme. We performed a population-based open cohort study of all residents aged 50-74, around 200,000 people. They were invited by mail to participate every other year. The gFOBT kits (Hemoccult II) were first provided by general practitioners, and then directly mailed to persons who failed to comply. The uptake decreased significantly across all rounds, from 54.3% to 47.1% (p < 0.0001), mainly in people younger than 60. The proportion of people screened by general practitioners increased significantly from 77.0% in the first round to 84.2% in the fourth (p < 0.01). Overall, 61.3% of the invited population participated at least once, and 14.3% had completed all the four tests. The colonoscopy uptake was around 91%, among the highest ever reported. Despite the involvement of general practitioners, the uptake and adherence to repeat testing are modest and deteriorate with time, so that the reduction in CRC mortality in reality will be significantly lower than that in the trials. The benefit-risk balance of the French programme is, at present, less favourable than that shown in the trials.

Su1224 Participation in the First Four Rounds of the Colorectal Cancer Screening Program With Guaiac Fecal Occult Blood Test Conducted in the Haut-Rhin (Alsace, France)

Organized screening programs depend on high participation rates to be effective and efficient. Whether uptake rates obtained in randomized controlled trials on colorectal cancer (CRC) screening with guaiac fecal occult blood test (gFOBT) are transposable in the real world is questionable. gFOBT has several drawbacks, one is the requirement for frequent testing, which may limit compliance. Aim: To assess participation in the first 4 rounds of an organized CRC screening program using gFOBT. Methods: Comparison of the determinants of participation in the first 4 rounds (R1 to R4) of the CRC screening programwith Hemoccult II implemented since 2003 in the Haut-Rhin, a French administrative area. We performed a population-based open cohort study of all average risk residents aged 50 74 years. They were invited to participate every other year. A first letter invited them to visit their general practitioner (GP) for CRC screening. Three recall letters were mailed to all those who had not complied, the second with a gFOBT kit. Results: Main results are presented in the table. The decrease in uptake was similar in men and women and was observed in all age groups except the 70 74 year age group. Overall, after 4 rounds, 242,292 persons had been invited and 34545 (14.3%) had completed 4 tests, 26675 (11.0%) 3 tests, 37193 (15.4%) 2 tests and 50070 (20.7%) 1 test. Overall, 148,483 (61.3%) persons had been screened at least once. Of 86,694 people who were eligible in all rounds, 34,545 (39.8%) had completed all the 4 tests, 8679 (10.0%) 3 tests, 8099 (9.3%) 2 tests, 6552 (7.6%) 1 test, and 28,819 (33.2%) 0 test. The uptake following the 2nd, 3rd and 4th invitation in people who never complied before was 17.0%, 8.8% and 5.5%, respectively. 16% of people who had participated in Rn did not participate in Rn+1. The proportion of people screened by GPs increased significantly from 76.9% in the 1st round to 84.0% in the 4th (p<0.01) while that of people screened by direct mailing of the gFOBT kit decreased significantly from 15.6% to 12.1% (p<0.01). The proportion of uptake following the first 2 invitation letters increased from R1 to R4 from 78.4% to 86.9%, while that following the mailing of the gFOBT kit decreased from 15.3% to 7.8%. The uptake decreased between years 2008 2009 and 2011 2012 from 34.3% to 31.7% in France and from 51.3% to 47.1% in our region. The latter uptake was among the highest achieved in France, where it varied from 7.1% to 51.4% depending on regions. Conclusion: The uptake and adherence to repeat testing are modest and deteriorate with time in the French organized population-based gFOBT CRC screening program, so that the reduction in CRC mortality will be significantly lower than in the trials. Effort is needed to enhance uptake and to reduce inequalities in participation related to sex, age, place of residence and deprivation.

Cutaneous lupus erythematosus and the association with systemic lupus erythematosus: a population-based cohort of 1088 patients in Sweden

Studies reporting the incidence of isolated cutaneous lupus erythematosus (CLE) are rare. To examine in a population-based cohort study the incidence of CLE and its subsets in Sweden. The short-term probability of receiving an additional diagnosis of systemic lupus erythematosus (SLE) is also assessed. A population-based open cohort study including all patients with CLE [International Classification of Diseases (ICD) code, ICD-10: L93] in Sweden, 2005-2007. Patients (n=1088) were identified in the Swedish National Patient Register. The incidence of CLE was 4·0/100,000; the female/male ratio was 3:1. Mean age at disease onset was 54 years. The most common subset was discoid lupus erythematosus (DLE) (80%, n = 868). A quarter of the patients (24%, n=260) were already diagnosed with SLE at the time they were diagnosed with CLE. During the whole observation period (2005-2007), an additional 18% (n = 107) were diagnosed with SLE, the probability of receiving an additional SLE diagnosis being highest for the subacute CLE (SCLE) subset. This is the first nationwide epidemiological study on CLE. We found the incidence of CLE to be about equal to that of SLE, and found a higher short-term probability for receiving an additional diagnosis with SLE than previously described for CLE. Subsets other than DLE and SCLE were rarely reported in our system; an update of the ICD codes for this diagnostic group could increase reporting of these more unusual cases. Our study clarifies that monitoring and follow-up are called for in this patient group due to the risk for SLE, and underscores the need for clear criteria for risk assessment in the large group of patients with CLE who also fulfil criteria for SLE.