Ambient air pollution and emergency department visits and hospitalisation for cardiac arrest: a population-based case-crossover study in Reykjavik, Iceland

OBJECTIVES

To assess the association between traffic-related ambient air pollution and emergency hospital visits for cardiac arrest.

DESIGN

Case-crossover design was used with a lag time to 4 days.

SETTING

The Reykjavik capital area and the study population was the inhabitants 18 years and older identified by encrypted personal identification numbers and zip codes.

PARTICIPANTS AND EXPOSURE

Cases were those with emergency visits to Landspitali University Hospital during the period 2006-2017 and who were given the primary discharge diagnosis of cardiac arrest according to the International Classification of Diseases 10th edition (ICD-10) code I46. The pollutants were nitrogen dioxide (NO₂), particulate matter with aerodynamic diameter less than 10 µm (PM₁₀), particulate matter with aerodynamic diameter less than 2.5 µm (PM_2.5) and sulfur dioxide (SO₂) with adjustment for hydrogen sulfide (H₂S), temperature and relative humidity.

MAIN OUTCOME MEASURE

OR and 95% CIs per 10 µg/m³ increase in concentration of pollutants.

RESULTS

The 24-hour mean NO₂ was 20.7 µg/m³, mean PM₁₀ was 20.5 µg/m³, mean PM_2.5 was 12.5 µg/m³ and mean SO₂ was 2.5 µg/m³. PM₁₀ level was positively associated with the number of emergency hospital visits (n=453) for cardiac arrest. Each 10 µg/m³ increase in PM₁₀ was associated with increased risk of cardiac arrest (ICD-10: I46), OR 1.096 (95% CI 1.033 to 1.162) on lag 2, OR 1.118 (95% CI 1.031 to 1.212) on lag 0-2, OR 1.150 (95% CI 1.050 to 1.261) on lag 0-3 and OR 1.168 (95% CI 1.054 to 1.295) on lag 0-4. Significant associations were shown between exposure to PM₁₀ on lag 2 and lag 0-2 and increased risk of cardiac arrest in the age, gender and season strata.

CONCLUSIONS

A new endpoint was used for the first time in this study: cardiac arrest (ICD-10 code: I46) according to hospital discharge registry. Short-term increase in PM₁₀ concentrations was associated with cardiac arrest. Future ecological studies of this type and their related discussions should perhaps concentrate more on precisely defined endpoints.

Ambient nitrogen dioxide is associated with emergency hospital visits for atrial fibrillation: a population-based case-crossover study in Reykjavik, Iceland

BACKGROUND

In Iceland air quality is generally good; however, previous studies indicate that there is an association between air pollution in Reykjavik and adverse health effects as measured by dispensing of medications, mortality, and increase in health care utilisation. The aim was to study the association between traffic-related ambient air pollution in the Reykjavik capital area and emergency hospital visits for heart diseases and particularly atrial fibrillation and flutter (AF).

METHODS

A multivariate time-stratified case-crossover design was used to study the association. Cases were those patients aged 18 years or older living in the Reykjavik capital area during the study period, 2006-2017, who made emergency visits to Landspitali University Hospital for heart diseases. In this population-based study, the primary discharge diagnoses were registered according to International Classification of Diseases, 10th edition (ICD-10). The pollutants studied were NO₂, PM₁₀, PM_2.5, and SO_2, with adjustment for H₂S, temperature, and relative humidity. The 24-h mean of pollutants was used with lag 0 to lag 4.

RESULTS

During the study period 9536 cases of AF were identified. The 24-h mean NO₂ was 20.7 μg/m³. Each 10 μg/m³ increase in NO₂ was associated with increased risk of heart diseases (ICD-10: I20-I25, I44-I50), odds ratio (OR) 1.023 (95% CI 1.012-1.034) at lag 0. Each 10 μg/m³ increase in NO₂ was associated with an increased risk of AF (ICD-10: I48) on the same day, OR 1.030 (95% CI: 1.011-1.049). Females were at higher risk for AF, OR 1.051 (95% CI 1.019-1.083) at lag 0, and OR 1.050 (95% CI 1.019-1.083) at lag 1. Females aged younger than 71 years had even higher risk for AF, OR 1.077 (95% CI: 1.025-1.131) at lag 0. Significant associations were found for other pollutants and emergency hospital visits, but they were weaker and did not show a discernable pattern.

CONCLUSIONS

Short-term increase in NO₂ concentrations was associated with heart diseases, more precisely with AF. The associations were stronger among females, and among females at younger age. This is the first study in Iceland that finds an association between air pollution and cardiac arrhythmias, so the results should be interpreted with caution.

The suppressive function of human CD8(+) iTregs is inhibited by IL-1β and TNFα

CD8(+) Tregs display an immunoregulatory activity and may play an essential role in the immunopathology of several diseases. Therefore, their therapeutic potential is exquisite and further studies on their differentiation and function are essential. The aim of this study was to evaluate the role of the innate immune system in CD8(+) iTreg differentiation and function. Naive human CD8(+) CD25(-) CD45RA(+) T cells were cultured in Treg-inducing conditions with or without IL-1β, TNFα or monocyte-derived dendritic cells (DCs). The differentiation of CD8(+) CD127(-) CD25(hi) FoxP3(hi) -induced Tregs (CD8(+) iTregs) is dependent on TGF-β1 and IL-2, which had synergistic effect upon their differentiation. CD8(+) iTregs were also induced in a coculture with allogeneic mature DCs (mDCs). The CD8(+) iTregs suppressive function was confirmed, which was diminished in the presence of IL-1β and TNFα. The IL-1β-prevented suppressive function was associated with reduced secretion of IL-10 and IFNγ, whereas the presence of TNFα did not affect their secretion. Furthermore, the presence of TNFα reduced IL-10 and TGF-β1 secretion by CD8(+) iTregs, whereas only IL-10 secretion was decreased by IL-1β. Together, these results suggest that IL-1β and TNFα prevent IL-2- and TGF-β1-driven CD8(+) iTregs suppressive function in human T cells. Such pro-inflammatory innate immune response possibly mediates its negative tolerogenic effect through reduced IFNγ-, IL-10- and TGF-β1-driven mechanism.

Accuracy evaluation of five blood glucose monitoring systems: the North American comparator trial

BACKGROUND

This study evaluated differences in accuracy between the CONTOUR® NEXT EZ (EZ) blood glucose monitoring system (BGMS) and four other BGMSs [ACCU-CHEK® Aviva (ACAP), FreeStyle Freedom Lite® (FFL), ONE TOUCH® Ultra®2 (OTU2), and TRUEtrack® (TT)].

METHODS

Up to three capillary blood samples (N = 393) were collected from 146 subjects with and without diabetes. One sample per subject was tested with fresh (natural) blood; the other samples were glycolyzed to lower blood glucose to <70 mg/dl. Meter results were compared with results from plasma from the same sample tested on a Yellow Springs Instruments (YSI) 2300 STAT PlusTM glucose analyzer. Blood glucose monitoring system accuracy was compared using mean absolute relative difference (MARD; from laboratory reference method results) and other analyses. Separate analyses on fresh (natural) samples only were conducted to determine potential effects of glycolysis on MARD values of systems utilizing glucose-oxidase-based test strip chemistry.

RESULTS

Across the tested glucose range, the EZ had the lowest MARD of 4.7%; the ACAP, FFL, OTU2, and TT had MARD values of 6.3%, 18.3%, 23.4%, and 26.2%, respectively. For samples with glucose concentrations <70 mg/dl, the EZ had the lowest MARD (0.65%), compared with the ACAP (2.5%), FFL (18.3%), OTU2 (22.4%), and TT (33.2%) systems.

CONCLUSIONS

The EZ had the lowest MARD across the tested glucose ranges when compared with four other BGMSs when all samples were analyzed as well as when natural samples only were analyzed.

Retinopathy in old persons with and without diabetes mellitus: the Age, Gene/Environment Susceptibility--Reykjavik Study (AGES-R)

AIMS/HYPOTHESIS

We aimed to describe the prevalence of retinopathy in an aged cohort of Icelanders with and without diabetes mellitus.

METHODS

The study population consisted of 4,994 persons aged ≥ 67 years, who participated in the Age, Gene/Environment Susceptibility-Reykjavik Study (AGES-R). Type 2 diabetes mellitus was defined as HbA(1c) ≥ 6.5% (>48 mmol/mol). Retinopathy was assessed by grading fundus photographs using the modified Airlie House adaptation of the Early Treatment Diabetic Retinopathy Study protocol. Associations between retinopathy and risk factors were estimated using odds ratios obtained from multivariate analyses.

RESULTS

The overall prevalence of retinopathy in AGES-R was 12.4%. Diabetes mellitus was present in 516 persons (10.3%), for 512 of whom gradable fundus photos were available, including 138 persons (27.0%, 95% CI 23.2, 31.0) with any retinopathy. Five persons (1.0%, 95% CI 0.3, 2.3) had proliferative retinopathy. Clinically significant macular oedema was present in five persons (1.0%, 95% CI 0.3, 2.3). Independent risk factors for retinopathy in diabetic patients in a multivariate model included HbA(1c), insulin use and use of oral hypoglycaemic agents, the last two being indicators of longer disease duration. In 4478 participants without diabetes mellitus, gradable fundus photos were available for 4,453 participants, with retinopathy present in 476 (10.7%, 95% CI 9.8, 11.6) and clinically significant macular oedema in three persons. Independent risk factors included increasing age and microalbuminuria.

CONCLUSIONS/INTERPRETATION

Over three-quarters (78%) of retinopathy cases were found in persons without diabetes and a strong association between microalbuminuria and non-diabetic retinopathy was found. These results may have implications for patient management of the aged.

Accuracy of the CONTOUR® blood glucose monitoring system

OBJECTIVE

The aim of the study was to assess the accuracy of the CONTOUR® blood glucose monitoring system (BGMS) according to the International Organization for Standardization's International Standard 15197 (ISO 15197:2003) guidelines and to more stringent criteria.

METHOD

Finger stick blood samples from 105 subjects with diabetes (25 with type 1, 77 with type 2, and 3 with type unknown) were tested using the CONTOUR BGMS and YSI glucose analyzer.

RESULTS

99.3% of results were within ISO 15197:2003 criteria (±15 mg/dl of YSI results at glucose concentrations <75 mg/dl and ±20% at glucose concentrations ≥75 mg/dl). Additionally, 96.7% of results were accurate according to more stringent criteria (±15 mg/dl of YSI results for glucose concentrations <100 mg/dl and ±15% for glucose concentrations ≥100 mg/dl). Error grid analysis showed that 99.3% and 0.7% of results were within zones A and B, respectively.

CONCLUSION

The CONTOUR BGMS exceeded both the minimum acceptable accuracy based on ISO 15197:2003 and the more stringent accuracy criteria.

Reproducibility and accuracy of body composition assessments in mice by dual energy x-ray absorptiometry and time domain nuclear magnetic resonance

OBJECTIVE: To assess the accuracy and reproducibility of dual-energy absorptiometry (DXA; PIXImus(™)) and time domain nuclear magnetic resonance (TD-NMR; Bruker Optics) for the measurement of body composition of lean and obese mice. SUBJECTS AND MEASUREMENTS: Thirty lean and obese mice (body weight range 19-67 g) were studied. Coefficients of variation for repeated (x 4) DXA and NMR scans of mice were calculated to assess reproducibility. Accuracy was assessed by comparing DXA and NMR results of ten mice to chemical carcass analyses. Accuracy of the respective techniques was also assessed by comparing DXA and NMR results obtained with ground meat samples to chemical analyses. Repeated scans of 10-25 gram samples were performed to test the sensitivity of the DXA and NMR methods to variation in sample mass. RESULTS: In mice, DXA and NMR reproducibility measures were similar for fat tissue mass (FTM) (DXA coefficient of variation [CV]=2.3%; and NMR CV=2.8%) (P=0.47), while reproducibility of lean tissue mass (LTM) estimates were better for DXA (1.0%) than NMR (2.2%) (<P 0.05). Regarding accuracy, in mice, DXA overestimated (vs chemical composition) LTM (+1.7 ± 1.3 g [SD], ~ 8%, P <0.001) as well as FTM (+2.0 ± 1.2 g, ~ 46%, P <0.001). NMR estimated LTM and FTM virtually identical to chemical composition analysis (LTM: -0.05 ± 0.5 g, ~0.2%, P =0.79) (FTM: +0.02 ± 0.7 g, ~15%, P =0.93). DXA and NMR-determined LTM and FTM measurements were highly correlated with the corresponding chemical analyses (r(2)=0.92 and r(2)=0.99 for DXA LTM and FTM, respectively; r(2)=0.99 and r(2)=0.99 for NMR LTM and FTM, respectively.) Sample mass did not affect accuracy in assessing chemical composition of small ground meat samples by either DXA or NMR. CONCLUSION: DXA and NMR provide comparable levels of reproducibility in measurements of body composition lean and obese mice. While DXA and NMR measures are highly correlated with chemical analysis measures, DXA consistently overestimates LTM and FTM (by ~8% and ~46%, respectively), while NMR only slightly underestimates LTM (by ~0.2%) and overestimates FTM (~15%.) The NMR method also has practical advantages compared to DXA, such as speed of measurement and the ability to scan unanesthetized animals.

Journeying through labour and delivery: perceptions of women who have given birth

OBJECTIVE

The aim of this study was to explore the essential structure of the lived experience of childbearing, as seen from the perspective of women who have given birth.

DESIGN, SETTING, AND PARTICIPANTS

The phenomenological perspective of qualitative research theory guided the methodological approach to the study, in which interactive interviews were conducted with a purposeful sample of fourteen mothers of healthy babies in Akureyri and Reykjavik, the two most inhabited places in Iceland.

FINDINGS

The metaphor of a woman journeying through labour and delivery was chosen to symbolize the lived experience of giving birth to a healthy baby. This encompasses four major categories: influences of circumstances and expectations before the journey's commencement; a sense of self during the journey which encompasses a sense of being in a private world, the sense of control, the need for caring and understanding and the need for a sense of security; the journey through labour and delivery itself; and finally the first sensitive hours of motherhood and the perception of the uniqueness of birth as a life experience at the journey's end. The study has the potential of increasing the knowledge and understanding of giving birth as a life experience, and therefore, has implications for midwives and nurses, as well as for women and their supporters.

KEY CONCLUSIONS

The lived experience of giving birth is a powerful life experience which is coloured by circumstances and expectations of the woman, her sense of self during the journey, the journey itself, as well as the first sensitive hours of motherhood.

IMPLICATIONS FOR PRACTICE

The study has the potential of increasing the knowledge and understanding of giving birth as a life experience, and therefore, has implications for midwives/nurse, as well as for women and their supporters.

Experiencing existential changes: the lived experience of having cancer

This phenomenological study was designed to explore the lived experience of having cancer, as perceived by people who have been diagnosed and treated for cancer. The aim of the study was to add to the knowledge and understanding of this complex human phenomenon. Data were collected through in-depth interviews with nine people who were in the remission or recovery phase of cancer. The interviews were tape-recorded and transcribed verbatim for each participant. Through intersubjective interactions and thematic analysis, the essential description of the lived experience of having cancer was constructed. The overriding theme of the lived experience of having cancer is "experiencing existential changes." Five basic subthemes were identified in the participants accounts, all of which are part of the existential changes involved in the lived experience of having cancer. These are: uncertainty, vulnerability, isolation, discomfort, and redefinition. The study can increase the understanding of what it is like to have cancer.

Intradermal challenge of Icelandic horses with extracts of four species of the genus Culicoides

Twenty-three Icelandic horses were challenged with extracts of four species of biting midges: Culicoides pulicaris, C chiopterus, C obsoletus and C impunctatus. Fourteen of the tested horses were affected with summer eczema. The horses were challenged intradermally with 0.1 ml of whole-body extracts of midges at a concentration of 0.01 or 0.005 per cent weight/volume. The skin reactions were measured after 30 minutes, 60 or 180 minutes and four, 24 and 48 hours after injection. Antigen titration showed that the reaction was dependent on the antigen concentration. Eight of nine unaffected horses failed to respond to any of the four antigens; the remaining animal responding to two of the four antigens. Ten of the 14 affected horses responded to at least three of the four antigens, while two of the animals in this group failed to respond to any. The mean responses to C chiopterus, C obsoletus and C impunctatus, read after 30 minutes, 60 minutes and four hours were significantly higher in the affected horses than in the unaffected horses. A significant difference was also found in the mean response to C chiopterus and C impunctatus, read after 24 hours.