Diffusion segregation and the disproportionate incidence of COVID-19 in African American communities

One of the most concerning aspects of the ongoing COVID-19 pandemic is that it disproportionately affects people from some specific ethnic and socio-economic minorities. In particular, since from the beginning of the pandemic it has been clear that people from Black and African American backgrounds seem to be hit especially hard by the virus, creating a substantial infection gap. The observed abnormal impact on these ethnic groups could probably be due to the co-occurrence of other known risk factors, including co-morbidity, poverty, level of education, access to healthcare, residential segregation and response to cures, although those factors do not seem able to explain fully and in depth the excess incidence of infections and deaths among African Americans. Here, we introduce the concept of diffusion segregation, that is the extent to which a given group of people is internally clustered or exposed to other groups, as a result of mobility and commuting habits. By analysing census and mobility data on major US cities, we found that the weekly excess COVID-19 incidence and mortality in African American communities at the beginning of the COVID-19 pandemic is significantly associated with their level of diffusion segregation. The results confirm that knowing where people commute to, rather than where they live, is potentially much more important to contain and curb the spreading of infectious diseases.

C-reactive protein and hypertension incidence in black and white Americans: REasons for Geographic And Racial Differences in Stroke (REGARDS) study

Background More inflammation is associated with greater risk incident hypertension, and black US adults have excess burden of hypertension. We investigated whether increased inflammation as quantified by higher C-reactive protein (CRP) explains the excess incidence in hypertension experienced by black US adults. Methods We included 6,548 black and white REGARDS participants without hypertension at baseline (2003-2007) who attended a second visit (2013-2016). Sex-stratified risk ratios (RR) for incident hypertension at the second exam in black compared to white individuals were estimated using Poisson regression adjusted for groups of factors known to partially explain the black-white differences in incident hypertension. We calculated the percent mediation by CRP of the racial difference in hypertension. Results Baseline CRP was higher in black participants. The black-white RR for incident hypertension in the minimally adjusted model was 1.33 (95% CI 1.22, 1.44) for males and 1.15 (1.04, 1.27) for females. CRP mediated 6.6% (95% CI 2.7, 11.3%) of this association in females and 19.7% (9.8, 33.2%) in males. In females, CRP no longer mediated the black-white RR in a model including waist circumference and body mass index, while in males the black-white difference was fully attenuated in models including income, education and dietary patterns. Conclusions Elevated CRP attenuated a portion of the unadjusted excess risk of hypertension in black adults, but this excess risk was attenuated when controlling for measures of obesity in females and diet and socioeconomic factors in males. Inflammation related to these risk factors might explain part of the black-white disparity in hypertension.

Haemolymphatic cancer among children in Sardinia, Italy: 1974–2003 incidence

ObjectivesTo explore the time trend and geographical distribution of childhood leukaemia incidence over the territory of the Italian region of Sardinia.SettingAll hospitals departments, diagnostic centres and social security agencies in Sardinia were regularly screened in 1974–2003 to identify, register and review the diagnoses of incident cases of haematological malignancies (HM).ParticipantsThe whole child population aged 0–14 resident in Sardinia.Primary and secondary outcome measuresIncidence and time trend of childhood HM and childhood acute lymphoblastic leukaemia (ALL) over the study period, and use of Bayesian methods to plot the probability of areas with excess incidence on the regional map.ResultsOverall, 675 HM cases, including 378 ALL cases, occurred among children aged 0–14 years resident in Sardinia in 1974–2003, with an incidence rate of 6.97×10-5 (95% CI 6.47 to 7.51) and 3.85×10-5 (95% CI 3.48 to 4.26), respectively. Incidence of HM and ALL showed an upward trend along the study period especially among females. Three communes out of the 356 existing in 1974, namely Ittiri, Villa San Pietro and Carbonia, stand out as areas with excess incidence of HM and ALL in particular and another, Carloforte, for ALL only.ConclusionsOur results might serve as convincing arguments for extending the coverage of routine cancer registration over the whole Sardinian population, while prompting further research on the genetic and environmental determinants in the areas at risk.

The respective parts of incidence and lethality in socioeconomic differences in cancer mortality. An analysis of the French network Cancer registries (FRANCIM) data

Background To determine relevant public health actions and to guide intervention priorities, it is of great importance to assess the relative contribution of incidence and lethality to social inequalities in cancer mortality. Methods The study population comprised 185,518 cases of cancer diagnosed between 2006 and 2009 recorded in the French registries. Survival was known for each patient (endpoint: 30/06/2013). Deprivation was assessed using the European Deprivation Index. We studied the influence of deprivation on mortality, incidence and lethality rates and quantified the respective proportions of incidence and lethality in social inequalities in mortality by calculating attributable deaths. Results For cancers with social inequalities both in incidence and lethality, excess mortality in deprived was mainly caused by social inequalities in incidence (e.g. men lung cancer: 87% of excess deaths in the deprived caused by inequalities in incidence). Proportions were more balanced for some cancer sites (e.g. cervical cancer: 56% incidence, 44% lethality). For cancer sites with a higher incidence in the least deprived (e.g. breast cancer), the excess-lethality in deprived leads entirely the higher mortality among the deprived. Conclusions Most of the excess mortality in deprived is due to the excess incidence of tobacco-dependent cancers and the excess lethality of screenable cancers.

Juvenile idiopathic arthritis and risk of cancer before and after the introduction of biological therapies

BackgroundThe risk of cancer, including any secular trends in risk, in patients with juvenile idiopathic arthritis (JIA) is incompletely understood.MethodsWe performed a register-based cohort study of patients with JIA from 2001 until 2017, identified via the Swedish Patient Register. Patients with JIA were matched to five population reference subjects. Patients and referents were followed up for incident cancers (via linkage to the Swedish Cancer Register) until 18 years of age or 31 December 2016.ResultsAmong the 6721 patients with JIA, we observed 10 incident malignancies (5 lymphoproliferative cancers) during 34 951 person-years of follow-up, corresponding to an excess incidence of 0.09 cancers per 1000 person-years (one extra case per 11 000 patients per year), an HR for cancer (all sites) of 1.4 (95% CI 0.7 to 2.9) and an HR for lymphoproliferative malignancies of 3.6 (95% CI 1.1 to 11.2). The rates of cancer in JIA did not increase over the study period. We noted no differences in the excess risk comparing periods before and after the introduction of biologic disease-modifying antirheumatic drugs (bDMARDs).DiscussionChildren and adolescents with JIA are at a slightly increased risk of lymphoproliferative (but not of other) malignancies. At the group level, there is no sign that this risk has increased further after the introduction of bDMARDs.

Excess stroke incidence in young Aboriginal people in South Australia: Pooled results from two population-based studies

Background Retrospective data indicate increased stroke incidence in Aboriginal/Torres Strait Islander (Indigenous) Australians, possibly with poorer outcomes. We present the first prospective population-based stroke incidence study in Indigenous Australians. Methods We pooled data from ASCEND and SEARCH, two prospective “ideal” South Australian stroke incidence studies, ASCEND conducted in urban Northwestern Adelaide (2009–2010) and SEARCH in five South Australian rural centers (2009–2011). We calculated age-standardized incidence for Aboriginal and non-Aboriginal people. Results The study population comprised 261,403 inhabitants. Among 432 first-ever strokes, 13 were in Aboriginal people (median age 51 vs. 78 years for non-Aboriginal people, p < 0.001). Age-standardized stroke incidence per 100,000 in Aboriginal patients (116, 95% CI: 95–137) was nearly two-fold that of non-Aboriginal patients (67, 95% CI: 51–84). Age-stratified excess incidence in Aboriginal people was restricted to those aged < 55 years (incidence rate ratio (IRR) 3.5, 95% CI: 2–7), particularly for intracerebral hemorrhage (IRR: 16, 95% CI: 4–61). Conclusion The excess stroke incidence in Aboriginal South Australians appears substantial, especially in those aged <55 years. Further work is required to delineate and address disparities.

Geographical variation of sporadic Legionnaires' disease analysed in a grid model

SUMMARYThe aim was to analyse variation in incidence of sporadic Legionnaires' disease in a geographical information system in three time periods (1990–2005) by the application of a grid model and to assess the model's validity by analysing variation according to grid position. Coordinates of the addresses at time of disease of 606 confirmed cases with Legionnaires' disease were obtained. The incidence was calculated in cells of 10×10 km in 25 different grids superimposed on a map of Denmark. A 95% and 99% threshold was applied to identify cells with excess incidence representing potential clusters. Four cells had excess incidence in all three time periods. The analysis in 25 different grid positions indicated a low risk of overlooking cells with excess incidence in a random grid. The coefficient of variation ranged from 0·08 to 0·11 independent of the threshold. By application of a random grid model we demonstrated that it was possible to detect small areas with excess incidence that were not detected in the present surveillance system.