Mortal Enemy
The Best of Times, the Worst of Times: Understanding Pro-cyclical Mortality
Ann Huff Stevens et al.
NBER Working Paper, December 2011
Abstract:
A growing literature documents cyclical movements in mortality and health. We examine this pattern more closely and attempt to identify the mechanisms behind it. Specifically, we distinguish between mechanisms that rely on fluctuations in own employment or time use and those involving factors that are external to the individual. Our investigation suggests that changes in individuals' own behavior contribute very little to pro-cyclical mortality. Looking across broad age and gender groups, we find that own-group employment rates are not systematically related to own-group mortality. In addition, we find that most of the additional deaths that occur during times of economic growth are among the elderly, particularly elderly women, who have limited labor force attachment. Focusing on mortality among the elderly, we show that cyclicality is especially strong for deaths occurring in nursing homes, and is stronger in states where a higher fraction of the elderly reside in nursing homes. We also demonstrate that staffing in skilled nursing facilities moves counter-cyclically. Taken together, these findings suggest that cyclical fluctuations in the mortality rate may be largely driven by fluctuations in the quality of health care.
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The Aging of Biomedical Research in the United States
Kirstin Matthews et al.
PLoS ONE, December 2011, e29738
Abstract:
In the past 30 years, the average age of biomedical researchers has steadily increased. The average age of an investigator at the National Institutes of Health (NIH) rose from 39 to 51 between 1980 and 2008. The aging of the biomedical workforce was even more apparent when looking at first-time NIH grantees. The average age of a new investigator was 42 in 2008, compared to 36 in 1980. To determine if the rising barriers at NIH for entry in biomedical research might impact innovative ideas and research, we analyzed the research and publications of Nobel Prize winners from 1980 to 2010 to assess the age at which their pioneering research occurred. We established that in the 30-year period, 96 scientists won the Nobel Prize in medicine or chemistry for work related to biomedicine, and that their groundbreaking research was conducted at an average age of 41 - one year younger than the average age of a new investigator at NIH. Furthermore, 78% of the Nobel Prize winners conducted their research before the age of 51, the average age of an NIH principal investigator. This suggested that limited access to NIH might inhibit research potential and novel projects, and could impact biomedicine and the next generation scientists in the United States.
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Katherine Keyes et al.
International Journal of Epidemiology, forthcoming
Background: The incidence and prevalence of autism have dramatically increased over the last 20 years. Decomposition of autism incidence rates into age, period and cohort effects disentangle underlying domains of causal factors linked to time trends. We estimate an age-period-cohort effect model for autism diagnostic incidence overall and by level of functioning.
Methods: Data are drawn from sequential cohorts of all 6 501 262 individuals born in California from 1992 to 2003. Autism diagnoses from 1994 to 2005 were ascertained from the California Department of Development Services Client Development and Evaluation Report.
Results: Compared with those born in 1992, each successively younger cohort has significantly higher odds of an autism diagnosis than the previous cohort, controlling for age and period effects. For example, individuals born in 2003 have 16.6 times the odds of an autism diagnosis compared with those born in 1992 [95% confidence interval (CI) 7.8-35.3]. The cohort effect observed in these data is stronger for high than for low-functioning children with an autism diagnosis.
Discussion: Autism incidence in California exhibits a robust and linear positive cohort effect that is stronger among high-functioning children with an autism diagnosis. This finding indicates that the primary drivers of the increases in autism diagnoses must be factors that: (i) have increased linearly year-to-year; (ii) aggregate in birth cohorts; and (iii) are stronger among children with higher levels of functioning.
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When Movies Matter: Exposure to Smoking in Movies and Changes in Smoking Behavior
Sonya Dal Cin, Mike Stoolmiller & James Sargent
Journal of Health Communication, January 2012, Pages 76-89
Abstract:
The authors investigated the association between exposure to smoking in movies and the initiation and progression of adolescent smoking over time among 6,522 U.S. adolescents (between the ages of 10 and 14 years, at baseline) in a nationally representative, 4-wave random-digit-dial telephone survey. They conducted a hazard (survival) analysis testing whether exposure to movie smoking and demographic, personality, social, and structural factors predict (a) earlier smoking onset and (b) faster transition to experimental (1-99 cigarettes/lifetime) and established smoking (>100 cigarettes/lifetime). Results suggest that higher exposure to movie smoking is associated with less time to trying cigarettes for the first time (adjusted hazard ratio = 1.66; 95% CI [1.37, 2.01]) but not with faster escalation of smoking behavior following initiation (adjusted hazard ratio = 1.53; 95% CI [0.84, 2.79]). In contrast, age, peer smoking, parenting style, and availability of cigarettes in the home were predictors of earlier onset and faster transition to established smoking. Thus, the authors concluded that the effect of exposure to mass-mediated images of smoking in movies may decline once adolescents have started to smoke, whereas peers and access to tobacco remain influential.
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The Virtuous Tax: Lifesaving and Crime-Prevention Effects of the 1991 Federal Alcohol-Tax Increase
Philip Cook & Christine Piette Durrance
NBER Working Paper, December 2011
Abstract:
On January 1, 1991, the federal excise tax on beer doubled, and the tax rates on wine and liquor increased as well. These changes are larger than the typical state-level changes that have been used to study the effect of price on alcohol abuse and its consequences. In this paper, we develop a method to estimate some important effects of those large 1991 changes, exploiting the interstate differences in alcohol consumption. We demonstrate that the relative importance of drinking in traffic fatalities is closely tied to per capita alcohol consumption across states. As a result, we expect that the proportional effects of the federal tax increase on traffic fatalities would be positively correlated with per capita consumption. We demonstrate that this is indeed the case, and infer estimates of the price elasticity and lives saved in each state. We repeat this exercise for other injury-fatality rates, and for nine categories of crime. For each outcome, the estimated effect of the tax increase is negatively related to average consumption, and that relationship is highly significant for the overall injury death rate, the violent crime rate, and the property crime rate. A conservative estimate is that the federal tax reduced injury deaths by 4.7%, or almost 7,000, in 1991.
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Magdalena Cerdá et al.
Drug and Alcohol Dependence, 1 January 2012, Pages 22-27
Background: Marijuana is the most frequently used illicit substance in the United States. Little is known of the role that macro-level factors, including community norms and laws related to substance use, play in determining marijuana use, abuse and dependence. We tested the relationship between state-level legalization of medical marijuana and marijuana use, abuse, and dependence.
Methods: We used the second wave of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a national survey of adults aged 18+ (n = 34,653). Selected analyses were replicated using the National Survey on Drug Use and Health (NSDUH), a yearly survey of ∼68,000 individuals aged 12+. We measured past-year cannabis use and DSM-IV abuse/dependence.
Results: In NESARC, residents of states with medical marijuana laws had higher odds of marijuana use (OR: 1.92; 95% CI: 1.49-2.47) and marijuana abuse/dependence (OR: 1.81; 95% CI: 1.22-2.67) than residents of states without such laws. Marijuana abuse/dependence was not more prevalent among marijuana users in these states (OR: 1.03; 95% CI: 0.67-1.60), suggesting that the higher risk for marijuana abuse/dependence in these states was accounted for by higher rates of use. In NSDUH, states that legalized medical marijuana also had higher rates of marijuana use.
Conclusions: States that legalized medical marijuana had higher rates of marijuana use. Future research needs to examine whether the association is causal, or is due to an underlying common cause, such as community norms supportive of the legalization of medical marijuana and of marijuana use.
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Alex Dregan & Martin Gulliford
American Journal of Epidemiology, forthcoming
Abstract:
From March to July of 2011, the authors investigated the prospective association between illicit drug use and cognitive functioning during the midadult years. A total of 8,992 participants who were surveyed at 42 years of age in the National Child Development Study (1999-2000) were included. The authors analyzed data on 3 cognitive functioning measures (memory index, executive functioning index, and overall cognitive index) when the participants were 50 years of age (2008-2009). Illicit drug use at 42 years of age was based on self-reported current or past use of any of 12 illicit drugs. Multivariable regression analyses were performed to estimate the association between different illicit drug use measures at 42 years of age and cognitive functioning at 50 years of age. A positive association was observed between ever (past or current) illicit drug use and cognitive functioning (β = 0.62, P < 0.001), although the effect size was small. Even though there was no clear evidence against the null hypothesis, drug dependence (β = -0.27, P = 0.58) and long-term illicit drug use (β = -0.04, P = 0.87) tended to be negatively associated with cognitive functioning. At the population level, it does not appear that current illicit drug use is associated with impaired cognitive functioning in early middle age. However, the authors cannot exclude the possibility that some individuals and groups, such as those with heavier or more prolonged use, could be harmed.
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Dipan Bose, Maria Segui-Gomez & Jeff Crandall
American Journal of Public Health, December 2011, Pages 2368-2373
Objectives: Motor vehicle trauma has been effectively reduced over the past decades; however, it is unclear whether the benefits are equally realized by the vehicle users of either sex. With increases in the number of female drivers involved in fatal crashes and similarity in driving patterns and risk behavior, we sought to evaluate if advances in occupant safety technology provide equal injury protection for drivers of either sex involved in a serious or fatal crash.
Methods: We performed a retrospective cohort study with national crash data between 1998 and 2008 to determine the role of driver sex as a predictor of injury outcome when involved in a crash.
Results: The odds for a belt-restrained female driver to sustain severe injuries were 47% (95% confidence interval=28%, 70%) higher than those for a belt-restrained male driver involved in a comparable crash.
Conclusions: To address the sex-specific disparity demonstrated in this study, health policies and vehicle regulations must focus on effective safety designs specifically tailored toward the female population for equity in injury reduction.
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Airports, Air Pollution, and Contemporaneous Health
Wolfram Schlenker & Reed Walker
NBER Working Paper, December 2011
Abstract:
Airports are some of the largest sources of air pollution in the United States. We demonstrate that daily airport runway congestion contributes significantly to local pollution levels and contemporaneous health of residents living nearby and downwind from airports. Our research design exploits the fact that network delays originating from large airports on the East Coast increase runway congestion in California, which in turn increases daily pollution levels around California airports. Using the component of California air pollution driven by airport congestion, we find that carbon monoxide (CO) leads to significant increases in hospitalization rates for asthma, respiratory, and heart related emergency room admissions that are an order of magnitude larger than conventional estimates: A one standard deviation increase in daily pollution levels leads to an additional $1 million in hospitalization costs for respiratory and heart related admissions for the 6 million individuals living within 10km (6.2 miles) of the 12 largest airports in California. While infants and the elderly are more sensitive to air pollution, we also find significant relationships for the adult population. The health impacts are driven by CO, not NO2 or O3, and occur at levels far below existing EPA mandates. Our results suggest there may be sizable morbidity benefits from lowering the existing CO standard.
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Estimating the value of the reduction in air pollution during the Beijing Olympics
Xiaoyan Du & Robert Mendelsohn
Environment and Development Economics, December 2011, Pages 735-749
Abstract:
This study estimates the willingness-to-pay (WTP) of Beijing residents in order to maintain the improved air quality experienced during the Olympic Games. A double-bounded contingent valuation method is applied to a survey of 566 Beijing residents. The results indicate that the mean annual WTP per household is between CNY 22,000 and 24,000, and the median WTP is around CNY 1,700. The WTP for this actually experienced improvement is significantly higher than the results from previous hypothetical WTP surveys in China.
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Cumulative impacts of mountaintop mining on an Appalachian watershed
Ty Lindberg et al.
Proceedings of the National Academy of Sciences, 27 December 2011, Pages 20929-20934
Abstract:
Mountaintop mining is the dominant form of coal mining and the largest driver of land cover change in the central Appalachians. The waste rock from these surface mines is disposed of in the adjacent river valleys, leading to a burial of headwater streams and dramatic increases in salinity and trace metal concentrations immediately downstream. In this synoptic study we document the cumulative impact of more than 100 mining discharge outlets and approximately 28 km2 of active and reclaimed surface coal mines on the Upper Mud River of West Virginia. We measured the concentrations of major and trace elements within the tributaries and the mainstem and found that upstream of the mines water quality was equivalent to state reference sites. However, as eight separate mining-impacted tributaries contributed their flow, conductivity and the concentrations of selenium, sulfate, magnesium, and other inorganic solutes increased at a rate directly proportional to the upstream areal extent of mining. We found strong linear correlations between the concentrations of these contaminants in the river and the proportion of the contributing watershed in surface mines. All tributaries draining mountaintop-mining-impacted catchments were characterized by high conductivity and increased sulfate concentration, while concentrations of some solutes such as Se, Sr, and N were lower in the two tributaries draining reclaimed mines. Our results demonstrate the cumulative impact of multiple mines within a single catchment and provide evidence that mines reclaimed nearly two decades ago continue to contribute significantly to water quality degradation within this watershed.
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Valuing mortality impacts of smoke exposure from major southern California wildfires
Ikuho Kochi et al.
Journal of Forest Economics, January 2012, Pages 61-75
Abstract:
While the mortality impacts of urban air pollution have been well addressed in the literature, very little is known about the mortality impacts and associated social cost from wildfire-smoke exposure. In an attempt to address this knowledge gap, we estimate the social cost associated with excess mortality due to smoke exposure during the 2003 southern California wildfires. Accounting for confounding factors such as seasonality and fluctuation of daily mortality levels, we identify 133 excess cardiorespiratory-related deaths caused by wildfire-smoke exposure. The mean estimated total mortality-related cost associated with the 2003 southern California wildfire event is approximately one billion U.S. dollars. Accounting for mortality costs associated with wildfire-smoke exposure allows for a better understanding of the tradeoffs associated with fuel treatment programs and suppression costs.
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Vernon Benignus, Philip Bushnell & William Boyes
Risk Analysis, December 2011, Pages 1935-1948
Abstract:
Acute solvent exposures may contribute to automobile accidents because they increase reaction time and decrease attention, in addition to impairing other behaviors. These effects resemble those of ethanol consumption, both with respect to behavioral effects and neurological mechanisms. These observations, along with the extensive data on the relationship between ethanol consumption and fatal automobile accidents, suggested a way to estimate the probability of fatal automobile accidents from solvent inhalation. The problem can be approached using the logic of the algebraic transitive postulate of equality: if A=B and B=C, then A=C. We first calculated a function describing the internal doses of solvent vapors that cause the same magnitude of behavioral impairment as ingestion of ethanol (A=B). Next, we fit a function to data from the literature describing the probability of fatal car crashes for a given internal dose of ethanol (B=C). Finally, we used these two functions to generate a third function to estimate the probability of a fatal car crash for any internal dose of organic solvent vapor (A=C). This latter function showed quantitatively (1) that the likelihood of a fatal car crash is increased by acute exposure to organic solvent vapors at concentrations less than 1.0 ppm, and (2) that this likelihood is similar in magnitude to the probability of developing leukemia from exposure to benzene. This approach could also be applied to other potentially adverse consequences of acute exposure to solvents (e.g., nonfatal car crashes, property damage, and workplace accidents), if appropriate data were available.