Different approaches to the analysis of causes of death during the COVID-19 epidemic

OBJECTIVE

The aim of the study is to assess the impact of the COVID-19 pandemic on causes of mortality through multiple methodological approaches.

MATERIALS AND METHODS

The causes of mortality in the Veneto region (Italy) during the first epidemic wave, March-April 2020, were compared with the corresponding months of the previous two years. Both the underlying cause of death (UCOD), and all diseases reported in the death certificate (multiple causes of death) were investigated; a further analysis was carried out through a simulation where the UCOD was selected after substituting ICD-10 codes for COVID with unspecified pneumonia.

RESULTS

Overall 10,222 deaths were registered in March-April 2020, corresponding to a 24% increase compared to the previous two years. COVID-19 was mentioned in 1,444 certificates, and selected as the UCOD in 1,207 deaths. Based on the UCOD, the increases in mortality were observed for COVID and related respiratory conditions, diabetes mellitus, hypertensive heart diseases, cerebrovascular diseases, and ill-defined causes. Multiple causes of death and the simulation analysis demonstrated further increases in mortality related to dementia/Alzheimer and chronic lower respiratory diseases.

CONCLUSIONS

This first report demonstrates an increase of several causes of death during the pandemic, underlying the need of a continuous surveillance of mortality records through different analytic strategies.

Perfluoroalkyl substances and lipid profile in exposed pregnant women in the Veneto Region, Italy

Background

Perfluoroalkyl substances (PFASs) are persistent and widespread environmental pollutants. Residents of a large area of the Veneto Region (North-Eastern Italy) were exposed to high concentrations of PFASs through drinking water from the late-1970s to 2013. PFASs have been consistently associated with raised serum lipids, but only few studies have been conducted among pregnant women, and none has stratified analyses by trimesters of gestation. Our main objective was to evaluate the association between perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) levels and lipid profiles in high-exposed pregnant women.

Methods

A cross-sectional analysis was conducted in 319 pregnant women (age 14-48 years) recruited in the Regional health surveillance program. Serum PFASs were measured by HPLC-MS/MS. Non-fasting serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) were measured by enzymatic assays in automated analysers, and low-density lipoprotein cholesterol (LDL-C) was calculated. The associations between ln-transformed PFASs (and categorized into quartiles) and lipids were assessed using generalized additive models. Analyses were adjusted for potential confounders and stratified according to pregnancy trimester.

Results

In the first trimester, plasma concentrations of both PFOA and PFOS were positively associated with TC. However in the third trimester PFOA levels were instead inversely significantly associated with TC and LDL-C levels. Overall, both PFOA and PFOS were positively associated with HDL-C, and PFOA negatively with LDL-C.

Conclusions

In a small highly exposed population of pregnant women, the associations between PFASs concentrations and lipid profile were modified by trimester of gestation. Patterns late in pregnancy were different to the positive associations with LDL-C generally found. Differential transfer and bioaccumulation of lipids and PFAS in the placenta across gestation might explain our findings.

Key messages

This study provides evidence of different patterns of PFAS associations with lipids in pregnant women across the trimesters of gestation. The different patterns of association from general population studies sheds light on the role of fetal nutrition during pregnancy affecting both lipids and PFAS in serum.

Perfluoroalkyl substances and blood pressure in exposed young population in the Veneto Region, Italy

Background

Residents in a large area of the Veneto Region (North-Eastern Italy) were exposed to perfluoroalkyl substances (PFASs) via drinking water. Studies on the association between PFASs and blood pressure (BP) levels are limited and results are inconsistent. Using cross-sectional data from the Regional health surveillance program, we aimed to quantify the associations between PFAS serum concentrations and blood pressure and hypertension prevalence.

Methods

The study included 16,224 individuals aged 20-39 years. Pregnant women (n = 327), participants with self-reported diagnosis or under treatment (n = 296) or with missing information on the selected covariates (n = 114) were excluded, leaving 15,487 subjects. Hypertension (HYP) was defined as any self-reported diagnosis, use of antihypertensive drugs, or raised systolic/diastolic blood pressure (SBP)≥140, DBP ≥90 mmHg). Serum PFASs were measured by HPLC-MS. Generalized additive models were used to investigate the relation between each PFAS (perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)) ln transformed and by decile, and SBP, DBP, HYP, adjusted for potential confounders.

Results

Both SBP and DBP increased significantly with an increase in the ln-transformed serum PFASs concentration in a monotonic way. The predicted increase in SBP and DBP were 1.62 (95% CI = 0.69, 2.55), 1.64 mmHg (95% CI = 0.96, 2.31) from lowest to highest decile of PFOA. The associations were stronger for SBP in men and DBP in women. One unit increase in each ln-PFAS was positively associated with an increased odds of HYP in men: PFOA OR = 1.07 (1.01-1.14), PFOS OR = 1.18 (1.05-1.32), PFHxS OR = 1.11 (1.03-1.19), PFNA OR = 1.19 (1.01-1.41).

Conclusions

Our findings suggest that exposure to PFAS is associated with increased blood pressure and thus may contribute as a risk factor for the development of cardiovascular diseases.

Key messages

Serum PFASs were associated with raised systolic blood pressure in men and diastolic blood pressure in women in a large highly exposed young adult population. Serum PFASs were associated with raised prevalence of hypertension in men.