Clara Tammy Kim

Heat-attributable deaths between 1992 and 2009 in Seoul, South Korea.

Background Climate change may significantly affect human health. The possible effects of high ambient temperature must be better understood, particularly in terms of certain diseases’ sensitivity to heat (as reflected in relative risks [RR]) and the consequent disease burden (number or fraction of cases attributable to high temperatures), in order to manage the threat. Purpose This study investigated the number of deaths attributable to abnormally high ambient temperatures in Seoul, South Korea, for a wide range of diseases. Method The relationship between mortality and daily maximum temperature using a generalized linear model was analyzed. The threshold temperature was defined as the 90th percentile of maximum daily temperatures. Deaths were classified according to ICD-10 codes, and for each disease, the RR and attributable fractions were determined. Using these fractions, the total number of deaths attributable to daily maximum temperatures above the threshold value, from 1992 to 2009, was calculated. Data analyses were conducted in 2012–2013. Results Heat-attributable deaths accounted for 3,177 of the 271,633 deaths from all causes. Neurological (RR 1.07; 95% CI, 1.04–1.11) and mental and behavioral disorders (RR 1.04; 95% CI, 1.01–1.07) had relatively high increases in the RR of mortality. The most heat-sensitive diseases (those with the highest RRs) were not the diseases that caused the largest number of deaths attributable to high temperatures. Conclusion This study estimated RRs and deaths attributable to high ambient temperature for a wide variety of diseases. Prevention-related policies must account for both particular vulnerabilities (heat-sensitive diseases with high RRs) and the major causes of the heat mortality burden (common conditions less sensitive to high temperatures).

Short-term air pollution exposure aggravates Parkinson’s disease in a population-based cohort

Increasing experimental evidence has suggested air pollution as new risk factor for neurological disease. Although long-term exposure is reportedly related to neurological disease, information on association with short-term exposure is scarce. We examined the association of short-term exposure to particles <2.5 μm (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and carbon monoxide (CO) with PD aggravation in Seoul from the National Health Insurance Service–National Sample Cohort, Korea during 2002–2013. PD aggravation cases were defined as emergency hospital admissions for primarily diagnosed PD and analyzed with a case-crossover analysis, designed for rare acute outcomes. Pollutants concentrations on case and control days were compared and effect modifications were explored. A unit increase in 8-day moving average of concentrations was significantly associated with PD aggravation. The association was consistent for PM2.5 (odds ratio [95% confidence interval]: 1.61 [1.14–2.29] per 10 μg/m3), NO2 (2.35 [1.39–3.97] per 10 ppb), SO2 (1.54 [1.11–2.14] per 1 ppb), and CO (1.46 [1.05–2.04] per 0.1 ppm). The associations were stronger in women, patients aged 65–74 years, and cold season, but not significant. In conclusion, short-term air pollution exposure increased risk of PD aggravation, and may cause neurological disease progression in humans.

The reciprocal interaction between LV remodelling and allograft outcomes in kidney transplant recipients

Objective This study aimed to investigate the incidence and related clinical factors of LV hypertrophy (LVH) regression after kidney transplantation and its effect on graft outcome. Methods Among the 3373 kidney transplant recipients who were enrolled in a multicentre cohort from 1997 to 2012, a total of 767 patients who underwent echocardiography before and after transplantation were included in this study followed for a median of 7.5 years. Results LVH regression steadily increased from 7.4% at 1 year to 35.4% at 5 years over the 5-year post-transplantation period. The probability of LVH regression decreased in the patients who received a kidney transplant due to end-stage renal disease of unknown aetiology (p=0.041) or who underwent pretransplant haemodialysis (p=0.020). The probability of LVH regression also decreased as the pretransplant LV mass index (p<0.001) and post-transplant systolic blood pressure increased (p=0.005). Conversely, LVH regression was significantly associated with the highest tertile of the pretransplant haemoglobin level (p=0.029). Furthermore, in the 5th year after transplantation, persistent LVH was independently associated with allograft failure (HR 1.95; 95% CI 1.14 to 3.33; p=0.015) and the LV mass index reliably predicted graft outcome. Conclusions LVH consistently regressed after kidney transplantation in most patients. Persistent LVH, low haemoglobin levels and elevated blood pressure were associated with an increased risk of allograft failure in kidney transplant recipients.

Circulating Tumor Necrosis Factor α Receptors Predict the Outcomes of Human IgA Nephropathy: A Prospective Cohort Study

The circulating tumor necrosis factor receptors (TNFRs) could predict the long-term renal outcome in diabetes, but the role of circulating TNFRs in other chronic kidney disease has not been reported. Here, we investigated the correlation between circulating TNFRs and renal histologic findings on kidney biopsy in IgA nephropathy (IgAN) and assessed the notion that the circulating TNFRs could predict the clinical outcome. 347 consecutive biopsy-proven IgAN patients between 2006 and 2012 were prospectively enrolled. Concentrations of circulating TNFRs were measured using serum samples stored at the time of biopsy. The primary clinical endpoint was the decline of estimated glomerular filtration rate (eGFR; ≥ 30% decline compared to baseline). Mean eGFR decreased and proteinuria worsened proportionally as circulating TNFR1 and TNFR2 increased (P < 0.001). Tubulointerstitial lesions such as interstitial fibrosis and tubular atrophy were significantly more severe as concentrations of circulating TNFRs increased, regardless of eGFR levels. The risks of reaching the primary endpoint were significantly higher in the highest quartile of TNFRs compared with other quartiles by the Cox proportional hazards model (TNFR1; hazard ratio 7.48, P < 0.001, TNFR2; hazard ratio 2.51, P = 0.021). In stratified analysis according to initial renal function classified by the eGFR levels of 60 mL/min/1.73 m2, TNFR1 and TNFR2 were significant predictors of renal progression in both subgroups. In conclusion, circulating TNFRs reflect the histology and clinical severity of IgAN. Moreover, elevated concentrations of circulating TNFRs at baseline are early biomarkers for subsequent renal progression in IgAN patients.

Seasonal analysis of the short-term effects of air pollution on daily mortality in Northeast Asia

The constituents and concentrations of pollutants, individual exposures, and biologic responses to air pollution may vary by season and meteorological conditions. However, evidence regarding seasonality of the acute effects of air pollution on mortality is limited and inconsistent. Herein, we examined seasonal patterns in the short-term associations of particulate matter (PM) smaller than 10μm (PM10) with daily mortality in 29 cities of three northeast Asian countries. Stratified time-series models were used to determine whether season altered the effect of PM10 on mortality. This effect was first quantified within each season and at each location using a time-series model, after which city-specific estimates were pooled using a hierarchical Bayesian model. In all data sets, 3,675,348 non-accidental deaths were registered from 1993 to 2009. In Japan, a 10μg/m3 increase in PM10 was significantly associated with increases in non-accidental mortality of 0.44% (95% confidence interval [CI]: 0.03%, 0.8%) in spring and 0.42% (0.02%, 0.82%) in fall. In South Korea, a 10μg/m3 increase in PM10 was significantly associated with increases in non-accidental mortality of 0.51% (0.01%, 1.01%) in summer and 0.45% (0.03%, 0.87%) in fall, in cardiovascular disease mortality of 0.96% (0.29%, 1.63%) in fall, and in respiratory disease mortality of 1.57% (0.40%, 2.75%) in fall. In China, a 10μg/m3 increase in PM10 was associated with increases in non-accidental mortality of 0.33% (0.01%, 0.66%) in summer and 0.41% (0.09%, 0.73%) in winter, in cardiovascular disease mortality of 0.41% (0.08%, 0.74%) in spring and 0.33% (0.02%, 0.64%) in winter, and in respiratory diseases mortality of 0.78% (0.27%, 1.30%) in winter. Our analyses suggest that the acute effect of particulate air pollution could vary seasonally and geographically.

Urinary Periostin Excretion Predicts Renal Outcome in IgA Nephropathy

Background: Periostin is a matricellular protein and plays a vital role in tissue regeneration, fibrosis and wound healing. However, data about its significance in nephrology are limited. We investigated the correlation between urinary periostin excretion and its clinical significance including renal histologic findings and prognosis in IgA nephropathy (IgAN). Methods: Of 399 patients from a glomerulonephritis cohort recruited between January 2009 and December 2014, 314 were enrolled. Serum and urine periostin (uPOSTN) were measured using enzyme-linked immunosorbent assay. We divided the patients into 3 groups by uPOSTN/creatinine (uPOSTN/Cr): group 1 (undetectable), group 2 (lower than the median) and group 3 (higher than the median). Results: The uPOSTN level was correlated with pathologic classifications and both initial and final IDMS-MDRD estimated glomerular filtration rates (eGFRs; p < 0.001). Histologically, group 3 patients were correlated with severe interstitial fibrosis/tubular atrophy (p = 0.004), interstitial inflammation (p = 0.007), hyaline arteriolosclerosis (p = 0.001) and glomerular sclerosis (p < 0.001). A higher initial uPOSTN/Cr level was associated with a greater decline in eGFR during follow-up (p = 0.043 when initial eGFR ≥60; p = 0.025 when eGFR <60 ml/min/1.73 m2), and the renal outcomes with end-stage renal disease (ESRD; p = 0.003), ESRD and/or eGFR decrease of >30% (p = 0.033) and ESRD and/or eGFR decrease of >50% (p = 0.046) occurred significantly more in group 3. In multivariate analysis, uPOSTN group 3 (hazards ratio 2.839, 95% CI 1.013-7.957; p = 0.047) was independently associated with ESRD in IgAN patients. Conclusion: uPOSTN/Cr value at initial diagnosis correlated with renal fibrosis and predicted the renal outcomes in patients with IgAN. It could be a promising urinary biomarker for renal fibrosis.

Association of Serum Phosphorus Concentration with Mortality and Graft Failure among Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES Hyperphosphatemia in kidney transplant recipients has been shown to predict poorer graft and patient survival. However, studies examining hypophosphatemia are scarce. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS To evaluate the association of serum phosphorus level with patient and graft survival, we performed a retrospective multicenter cohort study. Between January of 1997 and August of 2012, 2786 kidney transplant recipients (41.7±11.4 years; 59.3% men; 73.5% living donors; 26.1% with diabetes; 3.8% with prior history of cardiovascular disease) were classified into seven groups according to serum phosphorus levels 1 year after transplantation, with intervals of 0.5 mg/dl (lowest group, <2.5 mg/dl; highest group, ≥5.0 mg/dl; reference group, 3.5-3.99 mg/dl). Survival analysis was performed by defining baseline time point as 1 year after transplantation. RESULTS During median follow-up of 78.5 months, 60 patient deaths and 194 cases of graft loss occurred. In multivariate analysis, both lowest and highest serum phosphorus groups were associated with higher mortality, compared with the reference group (hazard ratio [HR], 4.82; 95% confidence interval [95% CI], 1.36 to 17.02; P=0.01; and HR, 4.24; 95% CI, 1.07 to 16.84; P=0.04, respectively). Higher death-censored graft loss was observed in the lowest and highest groups (HR, 3.32; 95% CI, 1.42 to 7.79; P=0.01; and HR, 2.93; 95% CI, 1.32 to 6.49; P=0.01, respectively), despite eGFR exhibiting no difference between the lowest group and reference group (65.4±19.3 versus 61.9±16.7 ml/min per 1.73 m2; P=0.33). Moreover, serum phosphorus showed a U-shape association with patient mortality and graft failure in restricted cubic spline curve analysis. CONCLUSIONS Serum phosphorus level 1 year after transplantation exhibits a U-shape association with death-censored graft failure and patient mortality in kidney transplant patients characterized by relatively high rate of living donor transplant and low incidence of diabetes and prior cardiovascular disease compared with Western countries.

Associations between malaria and local and global climate variability in five regions in Papua New Guinea

BackgroundMalaria is a significant public health issue in Papua New Guinea (PNG) as the burden is among the highest in Asia and the Pacific region. Though PNG’s vulnerability to climate change and sensitivity of malaria mosquitoes to weather are well-documented, there are few in-depth epidemiological studies conducted on the potential impacts of climate on malaria incidence in the country.MethodsThis study explored what and how local weather and global climate variability impact on malaria incidence in five regions of PNG. Time series methods were applied to evaluate the associations of malaria incidence with weather and climate factors, respectively. Local weather factors including precipitation and temperature and global climate phenomena such as El Niño-Southern Oscillation (ENSO), the ENSO Modoki, the Southern Annular Mode, and the Indian Ocean Dipole were considered in analyses.ResultsThe results showed that malaria incidence was associated with local weather factors in most regions but at the different lag times and in directions. Meanwhile, there were trends in associations with global climate factors by geographical locations of study sites.ConclusionsOverall heterogeneous associations suggest the importance of location-specific approaches in PNG not only for further investigations but also public health interventions in repose to the potential impacts arising from climate change.

Superior outcomes of kidney transplantation compared with dialysis An optimal matched analysis of a national population-based cohort study between 2005 and 2008 in Korea

Abstract Data regarding kidney transplantation (KT) and dialysis outcomes are rare in Asian populations. In the present study, we evaluated the clinical outcomes associated with KT using claims data from the Korean national public health insurance program. Among the 35,418 adult patients with incident dialysis treated between 2005 and 2008 in Korea, 1539 underwent KT. An optimal balanced risk set matching was attempted to compare the transplant group with the control group in terms of the overall survival and major adverse cardiac event–free survival. Before matching, the dialysis group was older and had more comorbidities. After matching, there were no differences in age, sex, dialysis modalities, or comorbidities. Patient survival was significantly better in the transplant group than in the matched control group (P < 0.001). In addition, the transplant group showed better major adverse cardiac event–free survival than the dialysis group (P < 0.001; hazard ratio, 0.49; 95% confidence interval, 0.32–0.75). Korean patients with incident dialysis who underwent long-term dialysis had significantly more cardiovascular events and higher all-cause mortality rates than those who underwent KT. Thus, KT should be more actively recommended in Korean populations.

Time‐varying maximal proteinuria correlates with adverse cardiovascular events and graft failure in kidney transplant recipients

In the general population, proteinuria is associated with progression to kidney failure, cardiovascular disease, and mortality. Here, we analyzed the effects of proteinuria on outcomes in kidney transplant recipients.