Social inequalities and dynamics of the early COVID-19 epidemic: a prospective cohort study in France.

OBJECTIVE: Although social inequalities in COVID-19 mortality by race, gender and socioeconomic status are well documented, less is known about social disparities in infection rates and their shift over time. We aim to study the evolution of social disparities in infection at the early stage of the epidemic in France with regard to the policies implemented. DESIGN: Random population-based prospective cohort. SETTING: From May to June 2020 in France. PARTICIPANTS: Adults included in the Epidémiologie et Conditions de Vie cohort (n=77 588). MAIN OUTCOME MEASURES: Self-reported anosmia and/or ageusia in three categories: no symptom, during the first epidemic peak (in March 2020) or thereafter (during lockdown). RESULTS: In all, 2052 participants (1.53%) reported anosmia/ageusia. The social distribution of exposure factors (density of place of residence, overcrowded housing and working outside the home) was described. Multinomial regressions were used to identify changes in social variables (gender, class and race) associated with symptoms of anosmia/ageusia. Women were more likely to report symptoms during the peak and after. Racialised minorities accumulated more exposure risk factors than the mainstream population and were at higher risk of anosmia/ageusia during the peak and after. By contrast, senior executive professionals were the least exposed to the virus with the lower rate of working outside the home during lockdown. They were more affected than lower social classes at the peak of the epidemic, but this effect disappeared after the peak. CONCLUSION: The shift in the social profile of the epidemic was related to a shift in exposure factors under the implementation of a stringent stay-at-home order. Our study shows the importance to consider in a dynamic way the gender, socioeconomic and race direct and indirect effects of the COVID-19 pandemic, notably to implement policies that do not widen health inequalities.

Does the air pollution model influence the evidence of socio-economic disparities in exposure and susceptibility?

Studies assessing socio-economic disparities in air pollution exposure and susceptibility are usually based on a single air pollution model. A time stratified case-crossover study was designed to assess the impact of the type of model on differential exposure and on the differential susceptibility in the relationship between ozone exposure and daily mortality by socio-economic strata (SES) in Montreal. Non-accidental deaths along with deaths from cardiovascular and respiratory causes on the island of Montreal for the period 1991-2002 were included as cases. Daily ozone concentration estimates at partictaipants' residence were obtained from the five following air pollution models: Average value (AV), Nearest station model (NS), Inverse-distance weighting interpolation (IDW), Land-use regression model with back-extrapolation (LUR-BE) and Bayesian maximum entropy model combined with a land-use regression (BME-LUR). The prevalence of a low household income (< 20,000/year) was used as socio-economic variable, divided into two categories as a proxy for deprivation. Multivariable conditional logistic regressions were used considering 3-day average concentrations. Multiplicative and additive interactions (using Relative Excess Risk due to Interaction) as well as Cochran's tests were calculated and results were compared across the different air pollution models. Heterogeneity of susceptibility and exposure according to socio-economic status (SES) were found. Ratio of exposure across SES groups means ranged from 0.75 [0.74-0.76] to 1.01 [1.00-1.02], respectively for the LUR-BE and the BME-LUR models. Ratio of mortality odds ratios ranged from 1.01 [0.96-1.05] to 1.02 [0.97-1.08], respectively for the IDW and LUR-BE models. Cochran's test of heterogeneity between the air pollution models showed important heterogeneity regarding the differential exposure by SES, but the air pollution model was not found to influence heterogeneity regarding the differential susceptibility. The study showed air pollution models can influence the assessment of disparities in exposure according to SES in Montreal but not that of disparities in susceptibility.

Trans-polar-fat: all Inuit are not equal.

As part of the rapid socio-cultural transition observed in Arctic populations, the Inuit diet is changing. We present original data derived from the baseline Inuit Health in Transition cohort study regarding biological levels of n-3 fatty acids and trans-fatty acids (TFA), lipids with opposite health effects found respectively in traditional marine diets and recently introduced low-quality imported foods. A total of 524 Inuit from the Disko Bay area (Greenland) and 888 Inuit from the fourteen communities of Northern Québec (Nunavik) participated in the study. We measured the fatty acid profile of erythrocyte (RBC) membrane phospholipids (PL) as a surrogate for individual intakes. Moreover, the contribution of store-bought foods to energy intakes was assessed through dietary questionnaires. Our results show that while n-3 fatty acid levels were slightly lower in Nunavik (9.4% of RBC membrane PL) than in Greenland (12.1%), TFA levels were on average nearly thrice as high in Nunavik Inuit (1.20%) as they were in Greenlanders (0.43%). Moreover, younger Nunavik Inuit accumulated higher intakes of TFA and lower intakes of n-3 fatty acids. Finally, the average proportion of energy derived from store-bought foods was high in both groups (77.5% and 83.5%), especially in youth. Our results call for action to rehabilitate and recover access to country foods and point to the importance for Nunavik and the entire circumpolar world to follow the example of Denmark and Greenland, which imposed a maximum content of 2 g/100 g fat on industrially produced trans-fats in 2003.

Trends of incident dialysis patients in Tunisia between 1992 and 2001.

BACKGROUND: Reliable information about the burden of end-stage renal disease (ESRD) is still scarce in the developing world. STUDY DESIGN: Observational study of a national dialysis registry. SETTING & PARTICIPANTS: Patients incident to dialysis therapy captured in the Tunisian registry of renal replacement therapy (RRT). PREDICTOR: Intervals from 1992 to 2001. OUTCOMES: Incidence rates of patients beginning dialysis therapy by age, sex, primary cause of ESRD, and region. RESULTS: The incidence of treated ESRD dramatically rose in Tunisia during the 10-year period to reach 158.8 cases/million people in 2000 to 2001. We hypothesize that the Tunisian population is experiencing better access to RRT, a decrease in mortality from other causes, and an increase in chronic kidney diseases from chronic disease causes. Chronic diseases that develop with aging and economic development prevailed in urban environments, with diabetic nephropathy rising at the rate of 16.1%/y, whereas renovascular diseases, which include hypertensive nephropathy, rose by 7.6% annually. Interestingly, tubulointerstitial nephropathies increased by 10.4% each year, which may be related to such environmental risk factors as dietary exposure to ochratoxin A, especially in rural settings. ESRD from unknown causes or with missing information about cause increased by 12.7% yearly. Large regional differences in total incidence persist despite constant efforts to level off inequalities in access to health care facilities and RRT treatment. LIMITATIONS: Possible underreferral for RRT, underreporting of cases, and misdiagnosis. CONCLUSIONS: The growing incidence of patients on dialysis therapy in Tunisia emphasizes that preventing chronic kidney disease and its progression should be a public health priority.