Cardiovascular Mortality and Leaded Aviation Fuel: Evidence from Piston-Engine Air Traffic in North Carolina.

Leaded fuel used by piston-engine aircraft is the largest source of airborne lead emissions in the United States. Previous studies have found higher blood lead levels in children living near airports where leaded aviation fuel is used. However, little is known about the health effects on adults. This study is the first to examine the association between exposure to aircraft operations that use leaded aviation fuel and adult cardiovascular mortality. We estimated the association between annual piston-engine air traffic and cardiovascular mortality among adults age 65 and older near 40 North Carolina airports during 2000 to 2017. We used several strategies to minimize the potential for bias due to omitted variables and confounding from other health hazards at airports, including coarsened exact matching, location-specific intercepts, and adjustment for jet-engine and other air traffic that does not use leaded fuel. Our findings are mixed but suggestive of adverse effects. We found higher rates of cardiovascular mortality within a few kilometers downwind of single- and multi-runway airports, though these results are not always statistically significant. We also found significantly higher cardiovascular mortality rates within a few kilometers and downwind of single-runway airports in years with more piston-engine air traffic. We did not consistently find a statistically significant association between cardiovascular mortality rates and piston-engine air traffic near multi-runway airports, where there was greater uncertainty in our measure of the distance between populations and aviation exposures. These results suggest that (i) reducing lead emissions from aviation could yield health benefits for adults, and (ii) more refined data are needed to obtain more precise estimates of these benefits. Subject Areas: Toxic Substances, Health, Epidemiology, Air Pollution, Ambient Air Quality. JEL codes: Q53, I18.

Role of Neurovascular Compression of Oculomotor Nerve in Ophthalmoplegic Migraine.

Ophthalmoplegic migraine is considered to occur more commonly in children than in adults. It commonly affects the oculomotor nerve among the cranial nerves. Demyelination of the nerve is proposed as the main mechanism for the etiology of ophthalmoplegic migraine, though it is not fully understood. Neurovascular compression as a cause of ophthalmoplegic migraine has not been well demonstrated in children. In this report, we present a case of a 13-year-old male with recurrent episodes of left ophthalmoplegic migraine. Oculomotor nerve enhancement with swelling was evident on MRI at the exit zone. Magnetic resonance angiography (MRA) revealed a sharp loop of the left posterior cerebral artery compressing the nerve. The case highlighted the unusual etiology of neurovascular compression resulting in ophthalmoplegic migraine in a pediatric patient. A supplemental case of ophthalmoplegic migraine in a seven-year-old male is also shown to highlight the role of neurovascular compression and the importance of using MR angiography to evaluate cases presenting clinically with ophthalmoplegic migraine.

Does short-term, airborne lead exposure during pregnancy affect birth outcomes? Quasi-experimental evidence from NASCAR's deleading policy.

BACKGROUND: There is evidence of a weak placental-fetal barrier to lead, suggesting that maternal lead exposure could affect the fetus. The health consequences for newborns from in utero lead exposure are not well understood. OBJECTIVES: We estimated the effects by trimester, of short-term (<1 week), airborne lead exposure during pregnancy on birth outcomes. METHODS: We use quasi-experimental variation in airborne lead exposure during pregnancy, based on NASCAR's deleading of racing fuel in 2007, in a difference-in-differences model, to estimate the effect of deleading on the birth outcomes of all live births (n = 147,673) in the Charlotte-Concord-Gastonia Metropolitan Statistical Area between 2004 and 2009. RESULTS: After deleading, children born to mothers residing <4000 m of Charlotte Motor Speedway (relative to those residing >10,000 m) experienced an average increase in birthweight (BW) of 102.50 g [P < 0.001]. The probability of low birthweight (LBW) declined by 0.045 [P = 0.001], preterm (PRE) births by 0.03 [P = 0.04], and small for gestational age (SGA) by 0.04 [P = 0.002]. We find that benefits accrue primarily in preterm LBW and SGA babies, and from decreased lead exposure in the first trimester. CONCLUSIONS: Short-term exposure to airborne lead during pregnancy adversely affects birth outcomes. Reducing even very brief exposure to airborne lead during pregnancy may improve birth outcomes.

Toxic exposure in America: estimating fetal and infant health outcomes from 14 years of TRI reporting.

We examine the effect of exposure to a set of toxic pollutants that are tracked by the Toxic Release Inventory (TRI) from manufacturing facilities on county-level infant and fetal mortality rates in the United States between 1989 and 2002. Unlike previous studies, we control for toxic pollution from both mobile sources and non-TRI reporting facilities. We find significant adverse effects of toxic air pollution concentrations on infant mortality rates. Within toxic air pollutants we find that releases of carcinogens are particularly problematic for infant health outcomes. We estimate that the average county-level decreases in various categories of TRI concentrations saved in excess of 13,800 infant lives from 1989 to 2002. Using the low end of the range for the value of a statistical life that is typically used by the EPA of $1.8M, the savings in lives would be valued at approximately $25B.

Blood pressure and heart rate effects following a single dose of bitter orange.

BACKGROUND: The ingredients of numerous "ephedra-free" dietary supplements used for weight loss include bitter orange, which contains sympathomimetic alkaloids such as synephrine. Due to the similarity in chemical structure to ephedrine and the potential sympathomimetic effects of synephrine, it is hypothesized that bitter orange may increase blood pressure (BP) and heart rate (HR). OBJECTIVE: To determine the effects on BP and HR after a single dose of bitter orange in healthy adults. METHODS: In a prospective, randomized, double-blind, placebo-controlled, crossover study, 15 young, healthy, adult subjects received either a single dose of Nature's Way Bitter Orange--a 900 mg dietary supplement extract standardized to 6% synephrine--or matching placebo, with a one week washout period. Systolic BP (SBP), diastolic BP (DBP), and HR were measured at baseline and every hour for 6 hours after administration. RESULTS: SBP after bitter orange was significantly increased versus placebo at hours 1-5 (p < 0.0001); the peak difference was 7.3 +/- 4.6 mm Hg. Although the baseline DBP was higher than after administration of both placebo and bitter orange, DBP after bitter orange was significantly increased versus placebo at hours 4 and 5 (p < or = 0.02); the peak difference was 2.6 +/- 3.8 mm Hg. HR was significantly increased after bitter orange versus placebo for hours 2-5 (p < 0.01); the peak difference was 4.2 +/- 4.5 beats/min. CONCLUSIONS: SBP, DBP, and HR were higher for up to 5 hours after a single dose of bitter orange versus placebo in young, healthy adults.

Response of CEDIA amphetamines assay after a single dose of bitter orange.

Bitter orange has recently been substituted as an ingredient in many "ephedra-free" dietary supplements used for weight loss. The primary active ingredient in bitter orange is synephrine. Previous reports have documented false-positive results from ephedrine with urine amphetamine assays. Because of the similarity in chemical structure of ephedrine and synephrine, it is hypothesized that ingestion of a bitter orange supplement may have the potential to cause false-positive results with urine amphetamine assays. The purpose of this study was to determine the response of the CEDIA Amphetamines Assay after ingestion of bitter orange. Six healthy adult male volunteers were administered a single oral dose of Nature's Way Bitter Orange, a 900-mg dietary supplement extract standardized to 6% synephrine. Urine specimens were collected at baseline and 3 and 6 hours post-administration. Additional urine specimens were collected from 1 subject at 9, 12, and 15 hours after administration. All specimens were analyzed by the CEDIA Amphetamines Assay. Urine specific gravity and pH also were measured. All urine specimens demonstrated a negative response to the CEDIA Amphetamines Assay. Urine specific gravity ranged from 1.007 to 1.028, and pH ranged from 5.0 to 7.0; thus, reducing the possibility that the negative results were caused by diluted specimens or reduced excretion of synephrine into alkaline urine. This information will be of value when health care providers or those who interpret drug screens are asked to provide consultation regarding the interference of bitter orange supplements with the CEDIA Amphetamines Assay. A single-dose of Nature's Way Bitter Orange was not found to cause a false-positive response to the CEDIA Amphetamines Assay in 6 healthy adult male volunteers.