Wayne R. Lawrence

Reliability of muscle blood flow and oxygen consumption response from exercise using near‐infrared spectroscopy

What is the central question of this study? Continuous‐wave near‐infrared spectroscopy, coupled with venous and arterial occlusions, offers an economical, non‐invasive alternative to measuring skeletal muscle blood flow and oxygen consumption, but its reliability during exercise has not been established. What is the main finding and its importance? Continuous‐wave near‐infrared spectroscopy devices can reliably assess local skeletal muscle blood flow and oxygen consumption from the vastus lateralis in healthy, physically active adults. The patterns of response exhibited during exercise of varying intensity agree with other published results using similar methodologies, meriting potential applications in clinical diagnosis and therapeutic assessment.

Is prehypertension more strongly associated with long-term ambient air pollution exposure than hypertension? Findings from the 33 Communities Chinese Health Study

Numerous studies have evaluated the effects of long-term exposure to ambient air pollution on hypertension. However, little information exists regarding its effects on prehypertension, a very common, but understudied cardiovascular indicator. We evaluated data from 24,845 adults (ages 18-74 years) living in three Northeastern Chinese cities in 2009. Blood pressure (BP) was measured by trained observers using a standardized mercuric-column sphygmomanometer. Three-year (from 2006 to 2008) average concentrations of particles with an aerodynamic diameter ≤10xa0μm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and ozone (O3) were calculated using data from monitoring stations. Effects were analyzed using generalized additive models and two-level regression analyses, controlling for covariates. We found positive associations of all pollutants with prehypertension (e.g. odds ratio (OR) was 1.17 (95% confidence interval (CI), 1.09-1.25) per interquartile range (IQR) of PM10) in a fully adjusted model, as compared to normotensive participants. These associations were stronger than associations with hypertension (e.g. OR was 1.03 (95% CI, 1.00, 1.07) per IQR of PM10). We have also found positive associations of all studied pollutants with systolic and diastolic BP: e.g., associations with PM10 per IQR were 1.24xa0mmHg (95% CI, 1.03-1.45) for systolic BP and 0.47xa0mmHg (95% CI, 0.33-0.61) for diastolic BP. Further, we observed that associations with BP were stronger in women and in older participants (systolic BP only). In conclusion, long-term exposure to ambient air pollution was more strongly associated with prehypertension than with hypertension, especially among females and the elderly. Thus, interventions to reduce air pollution are of great significance for preventing future cardiovascular events, particularly among individuals with prehypertension.

Gender-specific associations between serum isomers of perfluoroalkyl substances and blood pressure among Chinese: Isomers of C8 Health Project in China

Previous studies have demonstrated associations of perfluoroalkyl substances (PFASs), a group of highly persistent chemicals ubiquitous in wildlife and humans, with hypertension, but the relationships are mixed. Furthermore, academic literature on the relationship between isomers of PFASs and blood pressure (BP) and hypertension in populations from a higher pollution area is scant. We studied 1612 Chinese adults, ages 22-96years old, from Shenyang, China, utilizing high performance liquid chromatography-mass spectrometry to analyze isomers of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and other PFASs in blood serum. We used a mercury sphygmomanometer to measure BP. Hypertension was defined as a mean systolic BP (SBP) of at least 140mmHg, and/or diastolic BP (DBP) of at least 90mmHg, and/or use of antihypertensive medications. The results showed that increased serum concentrations of all (both branched and linear) isomers of PFASs were associated with higher prevalence of hypertension. Adjusted odds ratios for hypertension per ln-unit (ng/mL) increase in PFASs ranged from 1.10 (95%CI: 1.04, 1.17) for perfluorobutanoic acid (PFBA) to 1.26 (95%CI: 1.12, 1.42) for 3+4+5m PFOS, and the estimated increases in mean SBP and DBP ranged from 0.80mmHg (95%CI: 0.25, 1.34) for PFBA to 4.51mmHg (95%CI: 3.52, 5.51) for 3+4+5m PFOS, and from 0.51mmHg (95%CI: 0.01, 1.01) for perfluorodecanesulfonate (PFDS) to 2.48 (1.80, 3.16) for perfluorononanoic acid (PFNA), respectively. Compared with linear PFASs isomers, we identified more and stronger associations among branched PFASs isomers and blood pressure. Furthermore, females exhibited consistently stronger effects than males. In conclusion, this study is the first of its kind to show that not only PFASs positively associated with elevated blood pressure, but also that branched PFAS isomers are more frequently associated with blood pressure than linear PFAS isomers.

Humidity May Modify the Relationship between Temperature and Cardiovascular Mortality in Zhejiang Province, China

Background: The evidence of increased mortality attributable to extreme temperatures is widely characterized in climate-health studies. However, few of these studies have examined the role of humidity on temperature-mortality association. We investigated the joint effect between temperature and humidity on cardiovascular disease (CVD) mortality in Zhejiang Province, China. Methods: We collected data on daily meteorological and CVD mortality from 11 cities in Zhejiang Province during 2010–2013. We first applied time-series Poisson regression analysis within the framework of distributed lag non-linear models to estimate the city-specific effect of temperature and humidity on CVD mortality, after controlling for temporal trends and potential confounding variables. We then applied a multivariate meta-analytical model to pool the effect estimates in the 11 cities to generate an overall provincial estimate. The joint effects between them were calculated by the attributable fraction (AF). The analyses were further stratified by gender, age group, education level, and location of cities. Results: In total, 120,544 CVD deaths were recorded in this study. The mean values of temperature and humidity were 17.6 °C and 72.3%. The joint effect between low temperature and high humidity had the greatest impact on the CVD death burden over a lag of 0–21 days with a significant AF of 31.36% (95% eCI: 14.79–38.41%), while in a condition of low temperature and low humidity with a significant AF of 16.74% (95% eCI: 0.89, 24.44). The AFs were higher at low temperature and high humidity in different subgroups. When considering the levels of humidity, the AFs were significant at low temperature and high humidity for males, youth, those with a low level of education, and coastal area people. Conclusions: The combination of low temperature and high humidity had the greatest impact on the CVD death burden in Zhejiang Province. This evidence has important implications for developing CVD interventions.

Risk of glucose intolerance and gestational diabetes mellitus in relation to maternal habitual snoring during early pregnancy

Background Obstructive sleep apnea (OSA) or habitual snoring is known to be associated with impaired glucose tolerance and type 2 diabetes among both men and non-pregnant women. We examined the association of habitual snoring during early pregnancy with risk of impaired glucose tolerance (IGT) and gestational diabetes mellitus (GDM). Methods A cohort of 1,579 women was interviewed during early pregnancy. We collected information about snoring frequency during early pregnancy. Results from screening and diagnostic tests for IGT and GDM were abstracted from medical records. Multivariate logistic regression models were fitted to estimate odds ratios (OR) and 95% confidence intervals (95% CI) of IGT and GDM associated with snoring in early pregnancy. Results Overall, women who snored “most or all of the time” had a 2.1-fold increased odds of IGT (OR 2.10; 95% CI 1.31–3.35) and a 2.5-fold increased odds of GDM (OR 2.50; 95% CI 1.34–4.67) as compared with women who never snored. Compared with lean women (pre-pregnancy body mass index (BMI) <25 kg/m2) who did not snore, lean snorers had a 2-fold increased odds of GDM (OR = 1.99, 95% CI: 1.07–3.68). The odds of GDM risk was particularly elevated among overweight women (BMI ≥ 25 kg/m2) who snored (OR = 5.01; 95% CI 2.71–9.26). However, there was no evidence of an interaction between overweight and snoring with GDM risk (p-value = 0.144). Conclusions These findings, if confirmed, may have important implications for tailoring prenatal care for overweight pregnant women, and /or those with a history of habitual snoring in early pregnancy.

Association between long-term exposure to air pollution and sleep disorder in Chinese children: the Seven Northeastern Cities study

Study ObjectivesnThere is limited knowledge regarding the effects of air pollution on sleep disorders, particularly in children. The aim of this study is to investigate this association in Chinese children.nnnMethodsnDuring 2012-2013, 59754 children aged 2-17 years were randomly selected from 27 districts in seven northeastern Chinese cities. All participants sleep was evaluated with the Sleep Disturbance Scale for Children. Four year average concentrations of pollutants were calculated for particles with an aerodynamic diameter of ≤1 µm (PM1), ≤2.5 µm (PM2.5) from a spatial statistical model, and ≤10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO) from monitoring stations. To examine the effects, two-level regression analysis was used, controlling for covariates.nnnResultsnWe observed that sleep disorder was generally associated with all air pollutants, with the highest odds among PM1 exposure for male (odds ratio [OR] 1.55; 95% confidence interval [95% CI] 1.36-1.76) and female (OR 1.50; 95% CI 1.30-1.72) children. The overall strongest association with sleep disorder symptom was exposure to PM1 and Disorders of Excessive Somnolence (OR 1.43; 95% CI 1.30-1.58). PM1 and PM2.5 were strongly associated with all sleep disorder symptoms in females (ORs ranged for PM1 from 1.19 to 1.49; and PM2.5 1.18 to 1.44). The association between air pollutants and total sleep score was generally greater in female than in male children.nnnConclusionsnOur findings suggest that exposure to air pollutants increases the odds of sleep disorder in children and point to the need to make reducing exposure to air pollutants a public health priority.

Bayesian spatiotemporal analysis for association of environmental factors with hand, foot, and mouth disease in Guangdong, China

Hand, foot, and mouth disease (HFMD) remains a significant public health and economic burden in parts of China, particularly Guangdong Province. Although the association between meteorological factors and HFMD has been well documented, significant gaps remain in our understanding of the potential impact of environmental factors. Using county-level monthly HFMD data from China CDC and environmental data from multiple sources, we used spatiotemporal Bayesian models to evaluate the association between HFMD and environmental factors including vegetation index, proportion of artificial surface, road capacity, temperature and humidity, and assessed the spatial and temporal dynamic of the association. Statistically significant correlation coefficients from −0.056 to 0.36 (all Pu2009<u20090.05) were found between HFMD incidence and all environmental factors. The contributions of these factors for HFMD incidence were estimated to be 16.32%, 12.31%, 14.61%, 13.53%, and 2.63%. All environmental factors including vegetation index (Relative Risk: 0.889; Credible Interval: 0.883–0.895), artificial surface (1.028; 1.022–1.034), road capacity (1.033; 1.028–1.038), temperature (1.039; 1.028–1.05), and relative humidity (1.015; 1.01–1.021) were statistically retained in the final spatiotemporal model. More comprehensive environmental factors were identified as associating with HFMD incidence. Taking these environmental factors into consideration for prevention and control strategy might be of great practical significance.

Are the current thresholds, indicators, and time window for cold warning effective enough to protect cardiovascular health?

More extreme cold weather and larger weather variations have raised concerns regarding their effects on public health. Although prior studies assessed the effects of cold air temperature on health, especially mortality, limited studies evaluated wind chill temperatures on morbidity, and health effects under the current cold warning threshold. This study identified the thresholds, lag periods, and best indicators of extreme cold on cardiovascular disease (CVD) by comparing effects of wind chill temperatures and cold air temperatures on CVD emergency department (ED) visits in winter and winter transition months. Information was collected on 662,625 CVD ED visits from statewide hospital discharge dataset in New York State. Meteorological factors, including air temperature, wind speed, and barometric pressure were collected from National Oceanic and Atmospheric Administration. A case-crossover approach was used to assess the extreme cold-CVD relationship in winter (December-February) and transition months (November and March) after controlling for PM2.5. Conditional logistic regression models were employed to analyze the association between cold weather factors and CVD ED visits. We observed CVD effects occurred when wind chill temperatures were as high as -3.8u202f°C (25u202f°F), warmer than current wind chill warning standard (≤-28.8u202f°C or ≤-20u202f°F). Wind chill temperature was a more sensitive indicator of CVD ED visits during winter with temperaturesu202f≤u202f-3.8u202f°C (25u202f°F) with delay effect (lag 6); however, air temperature was better during transition months for temperaturesu202f≤u202f7.2u202f°C (45u202f°F) at earlier lag days (1-3). Among all CVD subtypes, hypertension ED visit had the strongest negative association with both wind chill temperature and air temperature. This study recommends modifying the current cold warning temperature threshold given larger proportions of CVD cases are occurring at considerably higher temperatures than the current criteria. We also recommend issuing cold warnings in winter transitional months.

Evidence from SINPHONIE project: Impact of home environmental exposures on respiratory health among school-age children in Romania

BACKGROUNDnExposure to indoor air pollutants at home was found to be associated with respiratory diseases. As lifestyle changes with rapid economic growth in Romania, the aim of our study is to describe the characteristics of Romanian homes and their impact on childrens respiratory health.nnnMETHODSnSelf-reported information on respiratory symptoms was collected from 280 Romanian elementary school students in 2011, and the symptoms were categorized into allergy, asthma-like, and flu-like symptoms. Home characteristics and demographic information were collected from questionnaires answered by parents. The association between home characteristics and respiratory health was assessed through multivariate logistic regression controlling for school indoor exposure.nnnRESULTSnAs compared to U.S. households, Romanian homes have a higher percentage of smokers, limited use of indoor climate control, and higher use of iron stoves. Exposure to environmental tobacco smoke was associated with both asthma and allergy symptoms. Additional risk factors identified for allergy symptoms include living in apartments, near pesticide sprayed areas, and the use of incense sticks. The significantly higher risk of flu-like symptoms was associated with mold and dampness issues, the use of air conditioner, gas heater/iron stove in childrens bedroom.nnnCONCLUSIONnOur findings suggest that an increase in respiratory symptoms among Romanian school-age children can be partly related to their environmental exposure at home. Since most of the identified risk factors are preventable, our results provide critical information and evidence for policymakers, to develop target intervention and education strategies.

Prognostic value of serum bilirubin in southern Chinese patients with advanced nasopharyngeal carcinoma

BACKGROUNDnWe evaluated the prognostic value of serum bilirubin in advanced nasopharyngeal carcinoma (NPC) patients.nnnMETHODSnSeven-hundred fifty-nine advanced NPC patients treated with definitive chemoradiotherapy were retrospectively analyzed. Serum indirect bilirubin (IBIL) and direct bilirubin (DBIL) were measured before treatment. To evaluate different cutoff points for serum bilirubin, we utilized ROC curves. The Kaplan-Meier method and log-rank test were adopted to calculate and compare survival outcomes. Cox proportional hazard models were used to perform univariate and multivariate analyses.nnnRESULTSnAt 5u202fy, IBIL >7.15u202fμmol/l were significantly associated with superior progression-free survival (PFS, 83.6% vs 70.3%; Pu202f<u202f.001), overall survival (OS, 88.6% vs 80.5%; Pu202f=u202f.012), distant metastasis-free survival (DMFS, 90.3% vs 82.8%; Pu202f=u202f.006), and locoregional relapse-free survival (LRFS, 92.1% vs 86.4%; Pu202f=u202f.048) than IBIL ≤7.15u202fμmol/l. Similarly, patients with DBIL >2.65u202fμmol/l had better prognosis across all outcomes than those of patients with DBIL ≤2.65u202fμmol/l (all Pu202f<u202f.05), except no difference was observed in LRFS (90.5% vs. 87.3%, Pu202f=u202f.195). Multivariate analyses showed that IBIL >7.15u202fμmol/l was an independent protective prognostic factor for PFS (HR, 0.57; 95% CI, 0.40-0.81; Pu202f=u202f.002), OS (HR, 0.67; 95% CI, 0.43-0.92; Pu202f=u202f.041), and DMFS (HR, 0.63; 95% CI, 0.40-0.98; Pu202f=u202f.034); while serum DBIL only remained significant for PFS (HR, 0.63; 95% CI, 0.44-0.89; Pu202f=u202f.009).nnnCONCLUSIONSnPretreatment IBIL and DBIL are potentially independent prognostic factors for patients with advanced NPC.