Disparities in the association between ambient temperature and preterm birth according to individual and regional characteristics: a nationwide time-stratified case-crossover study.

BACKGROUND: Several studies have reported that climate change elevates heat exposure in pregnant women and high temperatures during pregnancy are associated with preterm births (PTBs). Although the association might be disproportionate, related evidence remains sparse. We evaluated the disproportionate risk of PTB associated with ambient temperature during pregnancy by individual and regional characteristics in South Korea. METHODS: We collected data on birth certificates and daily mean temperatures during the period from 2011 to 2019. A time-stratified case-crossover design was used to investigate the association between temperature and PTB and stratified analyses were conducted to examine the effect modification of individual and regional characteristics. RESULTS: A total of 160,067 singleton PTBs were recorded in Korea from 2011 to 2019. A 5℃ increase in the mean temperature during the last four weeks before delivery was associated with an increased risk of PTB with an odds ratio (OR) of 1.03 (95% confidence interval [CI]: 1.02, 1.05), and the association was more evident in mothers aged ≥35 years (OR: 1.06 [95% CI: 1.03, 1.10]) and with low education levels (OR: 1.04 [95% CI: 1.02, 1.05]). Additionally, the estimated risk was evident in districts with lower medical resources and more prominent disparities were shown by individual and regional characteristics in rural areas than in urban areas. CONCLUSIONS: This study provides evidence that the risk of PTB related to ambient temperature is disproportionate by individual and regional characteristics and suggests the need for public health policies to alleviate the disparities, especially in rural areas.

Causal relationship between particulate matter 2.5 and diabetes: two sample Mendelian randomization.

Backgrounds: Many studies have shown particulate matter has emerged as one of the major environmental risk factors for diabetes; however, studies on the causal relationship between particulate matter 2.5 (PM2.5) and diabetes based on genetic approaches are scarce. The study estimated the causal relationship between diabetes and PM2.5 using two sample mendelian randomization (TSMR). Methods: We collected genetic data from European ancestry publicly available genome wide association studies (GWAS) summary data through the MR-BASE repository. The IEU GWAS information output PM2.5 from the Single nucleotide polymorphisms (SNPs) GWAS pipeline using pheasant-derived variables (Consortium = MRC-IEU, sample size: 423,796). The annual relationship of PM2.5 (2010) were modeled for each address using a Land Use Regression model developed as part of the European Study of Cohorts for Air Pollution Effects. Diabetes GWAS information (Consortium = MRC-IEU, sample size: 461,578) were used, and the genetic variants were used as the instrumental variables (IVs). We performed three representative Mendelian Randomization (MR) methods: Inverse Variance Weighted regression (IVW), Egger, and weighted median for causal relationship using genetic variants. Furthermore, we used a novel method called MR Mixture to identify outlier SNPs. Results: From the IVW method, we revealed the causal relationship between PM2.5 and diabetes (Odds ratio [OR]: 1.041, 95% CI: 1.008-1.076, P = 0.016), and the finding was substantiated by the absence of any directional horizontal pleiotropy through MR-Egger regression (ß = 0.016, P = 0.687). From the IVW fixed-effect method (i.e., one of the MR machine learning mixture methods), we excluded outlier SNP (rs1537371) and showed the best predictive model (AUC = 0.72) with a causal relationship between PM2.5 and diabetes (OR: 1.028, 95% CI: 1.006-1.049, P = 0.012). Conclusion: We identified the hypothesis that there is a causal relationship between PM2.5 and diabetes in the European population, using MR methods.

Air Pollution and Acute Kidney Injury in the U.S. Medicare Population: A Longitudinal Cohort Study.

BACKGROUND: Recent studies have reported the association between air pollution exposure and reduced kidney function. However, it is unclear whether air pollution is associated with an increased risk of acute kidney injury (AKI). OBJECTIVES: To address this gap in knowledge, we investigated the effect estimates of long-term exposures to fine particulate matter [PM ≤2.5µm in aerodynamic diameter (PM2.5)], nitrogen dioxide (NO2), and ozone (O3) on the risk of first hospital admission for AKI using nationwide Medicare data. METHODS: This nationwide population-based longitudinal cohort study included 61,300,754 beneficiaries enrolled in Medicare Part A fee-for-service (FFS) who were ≥65 years of age and resided in the continental United States from the years 2000 through 2016. We applied Cox-equivalent Poisson models to estimate the association between air pollution and first hospital admission for AKI. RESULTS: Exposure to PM2.5, NO2, and O3 was associated with increased risk for first hospital admission for AKI, with hazard ratios (HRs) of 1.17 (95% CI: 1.16, 1.19) for a 5-µg/m3 increase in PM2.5, 1.12 (95% CI: 1.11, 1.13) for a 10-ppb increase in NO2, and 1.03 (95% CI: 1.02, 1.04) for a 10-ppb increase in summer-period O3 (June to September). The associations persisted at annual exposures lower than the current National Ambient Air Quality Standard. DISCUSSION: This study found an association between exposures to air pollution and the risk of the first hospital admission with AKI, and this association persisted even at low concentrations of air pollution. Our findings provide beneficial implications for public health policies and air pollution guidelines to alleviate health care expenditures and the disease burden attributable to AKI. https://doi.org/10.1289/EHP10729.

Associations of biomarkers for exposure to tobacco smoke with lung cancer risk in Korea.

BACKGROUND: Nicotine metabolite ratio (NMR) can be used to predict total nicotine clearance. However, it is unknown whether NMR could be used as a marker of lung cancer risk. OBJECTIVE: To evaluate the blood metabolites of nicotine relating to the risk of developing lung cancer and investigate the combined effects of NMR and cigarette per day on the risk of lung cancer. METHODS: Among the 1,054 eligible subjects from the Korean Cancer Prevention Study-II biobank cohort, those with cotinine values below 0 ng/ml were excluded. Slow and fast metabolizer groups were defined using the median value of the NMR, calculated with the control group data, as the cut-point. RESULTS: The multivariable Cox proportional hazard models demonstrated that, the fast metabolizer group had a significantly higher risk of lung cancer than the slow metabolizer group (Adjusted HR: 2.02, 95% CI: 1.32-3.10). Fast metabolizers who smoked more than 15 cigarettes per day had an even higher risk of lung cancer (Adjusted HR: 3.51, 95% CI: 1.96-6.29) than the slow metabolizers who smoked less than 15 cigarettes per day. CONCLUSIONS: In summary, the NMR may be an effective marker for estimating tobacco-related disease risks such as lung cancer.

Association between Early Menopause, Gynecological Cancer, and Tobacco Smoking: A Cross-Sectional Study.

BACKGROUND: The rates of smoking among women are rising. Previous studies have shown that smoking is associated with early menopause. However, the association of gynecological cancer, including breast and cervical cancer, with early menopause and smoking, remains unclear. Therefore, this study aimed to determine the association between smoking and early menopause, breast cancer, and cervical cancer. METHODS: This cross-sectional study used data from the Korean National Health and Nutritional Survey Examination (KHANES) (2016-2018). Early menopause was defined as menopause before 50 years of age. RESULTS: A total of 4,481 participants were included in the analysis. There was no association between early menopause and cervical cancer (adjusted odds ratio [aOR]: 1.435, 95% confidence interval [CI]: 0.730-2.821), but women who had experienced early menopause had a significantly higher risk of breast cancer than women who had experienced normal menopause (aOR: 1.683, 95% CI: 1.089-2.602, p=0.019). Early menopause was not associated with an increased risk of breast cancer in ever-smoker (aOR: 0.475, 95% CI: 0.039-5.748), but was associated with a significantly increased risk of breast cancer in never-smokers (aOR: 1.828, 95% CI: 1.171-2.852). CONCLUSIONS: Early menopause was associated with an increased risk of breast cancer in women who had never smoked, but not in women who had ever smoked.

Bladder recovery by stem cell based cell therapy in the bladder dysfunction induced by spinal cord injury: systematic review and meta-analysis.

BACKGROUND: Bladder dysfunction induced by spinal cord injury (SCI) can become problematic and severely impair the quality of life. Preclinical studies of spinal cord injury have largely focused on the recovery of limb function while neglecting to investigate bladder recovery. OBJECTIVE: The present study was performed to investigate and review the effect of stem cell-based cell therapy on bladder recovery in SCI. METHODS: We conducted a meta-analysis of urodynamic findings of experimental trials that included studies of stem cell-based cell therapy in SCI. Relevant studies were searched using MEDLINE, EMBASE and Cochrane Library (January 1990 - December 2012). Final inclusion was determined by a urodynamic study involving detailed numerical values. Urodynamic parameters for analysis included voiding pressure, residual urine, bladder capacity and non-voiding contraction (NVC). Meta-analysis of the data, including findings from urodynamic studies, was performed using the Mantel-Haenszel method. RESULTS: A total of eight studies were included with a sample size of 224 subjects. The studies were divided into different subgroups by different models of SCI. After a stem cell-based cell therapy, voiding pressure (-6.35, p <0.00001, I2 = 77%), NVC (-3.58, p <0.00001, I2 = 82%), residual urine (-024, p = 0.004, I2 = 95%) showed overall significant improvement. Bladder capacity showed improvement after treatment only in the transection type (-0.23, p = 0.0002, I2 = 0%). CONCLUSION: After stem cell-based cell therapy in SCI, partial bladder recovery including improvement of voiding pressure, NVC, and residual urine was demonstrated. Additional studies are needed to confirm the detailed mechanism and to obtain an ideal treatment strategy for bladder recovery.

Measuring the improvement in health-related quality of life using King's health questionnaire in non-obese and obese patients with lower urinary tract symptoms after alpha-adrenergic medication: a preliminary study.

BACKGROUND: The efficacy of medical treatment among obese men with lower urinary tract symptoms (LUTS) has been less clear, especially regarding the improvement of QoL. We aimed to investigate the difference in efficacy and consequent satisfaction of life quality after medical treatment of male LUTS according to obesity. METHODS: An 8-week prospective study was performed for a total of 140 patients >50 years old with International Prostate Symptom Scores (IPSS) > 12 points and prostate volume > 20 mL. Obesity was determined by either body mass index (BMI) or waist circumference (WC). Patients were divided into 2 groups according to BMI or WC. Patients received tamsulosin at a dose of 0.4 mg daily for 8 weeks. The changes from baseline in the IPSS, maximal urinary flow rate (Qmax), post-void residual volume, questionnaire of quality of life (QoL), and King's Health Questionnaire (KHQ) were analyzed. RESULTS: Of the 150 enrolled patients, 96 completed the study. Seventy-five patients (78.1%) had BMI ≥ 23 kg/m2, and 24 (25.0%) had WC > 90 cm. Overall, the IPSS, IPSS QoL, and total KHQ showed significant improvement. Obese (BMI ≥ 23 kg/m2) and non-obese (BMI < 23 kg/m2) both showed improvement of the IPSS and IPSS QoL scores, but only the obese (BMI ≥ 23 kg/m2) group showed improvement of the total KHQ score (P < 0.001 vs. P = 0.55). Only the obese (WC > 90 cm) group showed improvement of the IPSS and total KHQ scores (P < 0.001). CONCLUSIONS: Our preliminary study showed the different efficacy of an alpha-blocker for improvement of LUTS and life quality according to obesity. Obese patients, defined by BMI or WC, showed the tendency toward a more favorable improvement of LUTS and life quality. TRIAL REGISTRATION: Current Controlled Trials 2010-058. Registered 2 September 2010 in Soonchunhyang University Hospital.