Kevin Lewis

February 07, 2013

The Status of Baby Boomers' Health in the United States: The Healthiest Generation?

Dana King et al.
JAMA Internal Medicine, forthcoming

"Despite their longer life expectancy over previous generations, US baby boomers have higher rates of chronic disease, more disability, and lower self-rated health than members of the previous generation at the same age. On a positive note, baby boomers are less likely to smoke cigarettes and experience lower rates of emphysema and myocardial infarction than the previous generation. The findings from the present study documenting poorer health status and increased rates of obesity, hypertension, diabetes, and hypercholesterolemia support an increased likelihood for continued rising health care costs and a need for increased numbers of health professionals as baby boomers age."


Sheepskin effects of education in the 10-year Framingham risk of coronary heart disease

Sze Yan Liu et al.
Social Science & Medicine, March 2013, Pages 31-36

While the association between education and adult health is well documented, it is unclear whether quantity (i.e. years of schooling) or credentials (i.e. degrees) drive this association. Individuals with degrees may have better health than their non-credentialed counterparts given similar years of schooling, the so-called "sheepskin" effect. This paper contributes to this line of inquiry by examining associations of educational degree and years of schooling with the Framingham Risk Score, a measure of 10-year risk of coronary heart disease (CHD), using data from a unique birth cohort (the New England Family Study; participants mean age 42 years) with prospective information on childhood health and intelligence quotient (IQ). According to our results, years of schooling were inversely associated with 10-year CHD risk in the unadjusted model but not in the fully adjusted models that included degree attainment. By contrast, associations between degree attainment and 10-year CHD risk remained significant in the fully adjusted models that included years of schooling. College degree holders had 10-year CHD risk 19% (95% CI: -33%, -2%) lower than individuals with HS degrees or less in the fully adjusted models. Subanalyses evaluating sheepskin effects on the individual components of the 10-year CHD risk algorithm showed the expected education gradient was generally noted for each of the individual components, with decreasing prevalence of "high risk" values associated with higher degree credentials. Our results suggest educational credentials provide an additional benefit to risk of coronary heart disease beyond schooling.


Childhood (Mis)fortune, Educational Attainment, and Adult Health: Contingent Benefits of a College Degree?

Markus Schafer, Lindsay Wilkinson & Kenneth Ferraro
Social Forces, forthcoming

College-educated adults are healthier than other people in the United States, but selection bias complicates our understanding of how education influences health. This article focuses on the possibility that the health benefits of college may vary according to childhood (mis)fortune and people's propensity to attain a college degree in the first place. Several perspectives from life course sociology offer competing hypotheses as to whether the most or the least advantaged see the greatest return of a college education. The authors use a national survey of middle-age American adults to assess risk of two cardiovascular health problems and mortality. Results from propensity score and hierarchical regression analysis indicate that the protective effect of college attainment is indeed heterogeneous. Further, the greatest returns are among those least likely to experience this life course transition (i.e., compensatory leveling). Explanations for this selection effect are offered, along with several directions for future research on the health benefits of completing college.


United States Counties with Low Black Male Mortality Rates

Robert Levine et al.
American Journal of Medicine, January 2013, Pages 76-80

Objective: In the United States, young and middle-aged black men have significantly higher total mortality than any other racial or ethnic group. We describe the characteristics of US counties with low non-Hispanic Black or African American male mortality (ages 25-64 years, 1999-2007).

Methods: Information was accessed through public data, the US Census, the US Compressed Mortality File, and the Native American Graves Repatriation Act military database.

Results: Of 1307 counties with black mortality rates classified as reliable by the National Center for Health Statistics (at least 20 deaths), 66 recorded lower mortality among black men than corresponding US whites. Most notable, 97% of the 66 counties were home to or adjacent a military installation versus 37% of comparable US counties (P < .001). Blacks in these counties had less poverty, higher percentages of elderly civilian veterans, and higher per capita income. Within these counties, national black:white disparities in mortality were eliminated for ischemic heart disease, accidents, diseases of the liver, chronic lower respiratory diseases, and mental disorder from psychoactive substance use. Application of age-, race-, ethnicity-, gender-, and urbanization-specific mortality rates from counties with relatively low mortality would reduce the black:white mortality rate ratio for black men aged 25 to 64 years from 1.67 to 1.20 nationally and to 1.00 in areas outside large central metropolitan areas.

Conclusions: These descriptive data demonstrate a small number of communities with low mortality rates among young and middle-aged black/African American men. Their characteristics may provide clinical and public health insights to reduce these higher mortality rates in the US population. Analytic epidemiologic studies are necessary to test these hypotheses.


Subjective Socioeconomic Status And Health: Relationships Reconsidered

Jenna Nobles, Miranda Ritterman Weintraub & Nancy Adler
Social Science & Medicine, forthcoming

Subjective status, an individual's perception of her socioeconomic standing, is a robust predictor of physical health in many societies. To date, competing interpretations of this correlation remain unresolved. Using longitudinal data on 8,430 older adults from the 2000 and 2007 waves of the Indonesia Family Life Survey, we test these oft-cited links. As in other settings, perceived status is a robust predictor of self-rated health, and also of physical functioning and nurse-assessed general health. These relationships persist in the presence of controls for unobserved traits, such as difficult-to-measure aspects of family background and persistent aspects of personality. However, we find evidence that these links likely represent bi-directional effects. Declines in health that accompany aging are robust predictors of declines in perceived socioeconomic status, net of observed changes to the economic profile of respondents. The results thus underscore the social value afforded good health status.


Racial Differences in the Association Between Night Shift Work and Melatonin Levels Among Women

Parveen Bhatti, Dana Mirick & Scott Davis
American Journal of Epidemiology, forthcoming

Reduced suppression of melatonin in response to working the night shift among people of Asian ancestry has been suggested as a possible explanation for the null results observed in a recent analysis of shift work and breast cancer risk in a Chinese cohort. The authors analyzed the impact of Asian versus white race on previously reported differences in urinary 6-sulfatoxymelatonin levels in a 2003-2008 study in Seattle, Washington, of female health-care workers that exclusively worked night or day shifts. A total of 225 white and 51 Asian participants were included in the analysis. Although 6-sulfatoxymelatonin levels were affected by night shift work in both racial groups, Asian night shift workers consistently showed 6-sulfatoxymelatonin levels that were closer to levels in day shift workers than did white night shift workers. Furthermore, differences in 6-sulfatoxymelatonin levels between white and Asian night shift workers relative to day shift workers were statistically significant in every instance (P < 0.05). These results suggest that Asians may be better able to maintain a "normal" circadian pattern of melatonin production compared with whites and suggest a biological mechanism by which Asian night shift workers may be at a reduced risk of cancer.


Psychosocial resources, aging, and natural killer cell terminal maturity

Suzanne Segerstrom, Ahmad Al-Attar & Charles Lutz
Psychology and Aging, December 2012, Pages 892-902

Psychosocial factors may influence aspects of immunological aging. The present study tested the hypothesis that psychosocial resources correlate with the expression of the cell surface maker CD57 on natural killer (NK) immune cells. CD57 is a marker of terminal maturation and senescence in this cell subset. The study further tested the relative contribution of specific resources in the social, psychological, financial, and status-skill domains, given the potential differential value of different resources for younger and older adults, and the contribution of relative versus absolute resources. Younger (n = 38) and older (n = 34) women completed measures of relative and absolute resources and had blood drawn. Examined both between groups and within the older women, older age and fewer total relative resources were associated with more CD57 expression on NK cells. One SD in resources was the equivalent of 5 years of aging among the older women. Among the specific resource types, a preponderance of financial resources, both relative and absolute, was associated with less CD57 expression on NK cells, and these relationships did not significantly vary between younger and older women. There was no evidence that depressive symptoms mediated the effects of resources on CD57 expression on NK cells. These findings provide support for the hypothesis that the sense that one has substantial resources, particularly with regard to finances and possessions, may retard age-associated aspects of the microenvironment in which NK cells develop and mature, independent of effects on distress, and this process may begin in younger adulthood.


Socioeconomic factors and leukocyte telomere length in a multi-ethnic sample: Findings from the multi-ethnic study of atherosclerosis (MESA)

Judith Carroll et al.
Brain, Behavior, and Immunity, February 2013, Pages 108-114

Previous findings have linked lower socioeconomic status (SES) with elevated morbidity and mortality. Leukocyte telomere length (LTL), which also has been associated with age-related disease morbidity and mortality, is a marker of aging at the cellular level, making it a valuable early biomarker of risk and an indicator of biological age. It is hypothesized that SES will be associated with LTL, indicating that SES influences disease risk by accelerating biological aging. In the present sample we test for associations of childhood SES and adult SES (i.e. education, income, home ownership) with LTL, and examine whether these associations vary by racial/ethnic group. Analyses on 963 subjects (18.7% White, 53% Hispanics, and 28.5% African American) from the stress ancillary study of the multi-ethnic study of atherosclerosis revealed a significant difference in LTL between home owners and renters in Hispanic and White participants (p < .05), but not amongst African Americans (p = .98). There were no linear associations of adult education or family income with LTL, however, there was an inverse association between father's education and LTL (p = .03). These findings suggest that for Whites and Hispanics renting vs. owning a home is associated with an older biological age; however we did not replicate previous findings linking education with LTL.


The Relationship Between Trees and Human Health: Evidence from the Spread of the Emerald Ash Borer

Geoffrey Donovan et al.
American Journal of Preventive Medicine, February 2013, Pages 139-145

Background: Several recent studies have identified a relationship between the natural environment and improved health outcomes. However, for practical reasons, most have been observational, cross-sectional studies.

Purpose: A natural experiment, which provides stronger evidence of causality, was used to test whether a major change to the natural environment - the loss of 100 million trees to the emerald ash borer, an invasive forest pest - has influenced mortality related to cardiovascular and lower-respiratory diseases.

Methods: Two fixed-effects regression models were used to estimate the relationship between emerald ash borer presence and county-level mortality from 1990 to 2007 in 15 U.S. states, while controlling for a wide range of demographic covariates. Data were collected from 1990 to 2007, and the analyses were conducted in 2011 and 2012.

Results: There was an increase in mortality related to cardiovascular and lower-respiratory-tract illness in counties infested with the emerald ash borer. The magnitude of this effect was greater as infestation progressed and in counties with above-average median household income. Across the 15 states in the study area, the borer was associated with an additional 6113 deaths related to illness of the lower respiratory system, and 15,080 cardiovascular-related deaths.

Conclusions: Results suggest that loss of trees to the emerald ash borer increased mortality related to cardiovascular and lower-respiratory-tract illness. This finding adds to the growing evidence that the natural environment provides major public health benefits.


Education Externalities on Longevity

Francesco Ricci & Marios Zachariadis
Economica, forthcoming

We argue that education exerts positive external effects on health, beyond the standard internal effects documented in the literature. We implement an innovative approach to control for endogeneity and omitted variables problems, and present evidence for the significant role played by higher education in explaining longevity across countries. Our findings provide empirical evidence in support of our hypothesis of educational externalities on health.


Fetal Health Shocks and Early Inequalities in Health Capital Accumulation

George Wehby, Kwame Nyarko & Jorge Lopez-Camelo
Health Economics, forthcoming

Several studies report socioeconomic inequalities in child health and consequences of early disease. However, not much is known about inequalities in health capital accumulation in the womb in response to fetal health shocks, which is essential for finding the earliest sensitive periods for interventions to reduce inequalities. We identify inequalities in birth weight accumulation as a result of fetal health shocks from the occurrence of one of the most common birth defects, oral clefts, within the first 9 weeks of pregnancy, using quantile regression and two datasets from South America and the USA. Infants born at lower birth weight quantiles are significantly more adversely affected by the health shock compared with those born at higher birth weight quantiles, with overall comparable results between the South American and US samples. These results suggest that fetal health shocks increase child health disparities by widening the spread of the birth weight distribution and that health inequalities begin in the womb, requiring interventions before pregnancy.


Air Pollution and Infant Mortality: Evidence from the Expansion of Natural Gas Infrastructure

Resul Cesur, Erdal Tekin & Aydogan Ulker
NBER Working Paper, January 2013

One of the consequences of rapid economic growth and industrialization in the developing world has been deterioration in environmental conditions and air quality. While air pollution is a serious threat to health in most developing countries, environmental regulations are rare and the determination to address the problem is weak due to ongoing pressures to sustain robust economic growth. Under these constraints, natural gas, as a clean, abundant, and highly-efficient source of energy, has emerged as an increasingly attractive source of fuel, which could address some of these environmental and health challenges faced by these countries without requiring a compromise on their economic development. In this paper, we use the variation across space and time in the expansion of natural gas infrastructure in Turkish provinces using data between 2001 and 2011. Our results indicate that the rate of increase in the use of natural gas has resulted in a significant reduction in the rate of infant mortality in Turkey. In particular, a one-percentage point increase in the rate of subscriptions to natural gas services would cause the infant mortality rate to decline by 4 percent, which could result in 348 infant lives saved in 2011 alone. These results are robust to a large number of specifications. Finally, we utilize supplemental data on total particulate matter and sulfur dioxide to produce direct estimates of the effects of these pollutants on infant mortality using natural gas expansion as an instrument. Our elasticity estimates from the instrumental variable analysis are 1.25 for particulate matter and 0.63 for sulfur dioxide.


Childhood adversity and inflammatory processes in youth: A prospective study

Natalie Slopenet al.
Psychoneuroendocrinology, February 2013, Pages 188-200

Background: Retrospective studies show that childhood adversity is associated with systemic inflammation in adulthood. Few prospective studies have examined whether childhood adversity influences inflammation in an observable manner during childhood or adolescence and if these effects are sustained over time.

Methods: Using longitudinal data from the Avon Longitudinal Study of Parents and Children, we examined associations between acute adverse events at seven time points prior to age 8 and inflammation at ages 10 and 15. Inflammatory markers at age 10 included interleukin-6 (IL-6; N = 4655) and C-reactive protein (CRP; N = 4647), and CRP was measured again at age 15 (N = 3286). We further evaluated whether body mass index (BMI), depression, or cigarette smoking mediated associations between adverse events and inflammation.

Results: Adverse events in middle childhood (occurring between ages 6 to 8), as well as cumulative adversity from birth to 8 years, were associated with higher levels of IL-6 and CRP at age 10. Adverse events reported in early childhood (1.5 years) or middle childhood, and cumulative adversity from birth through 8 years predicted increased levels of CRP at age 15, and these associations persisted after adjustment for CRP at age 10. Some, but not all, of these associations were mediated by BMI.

Conclusions: This study documents that exposure to adverse events prior to age 8 is associated with elevated inflammation at age 10 and in mid-adolescence. These findings provide prospective evidence for a biological mechanism by which early experiences may shape long-term health. Future studies with earlier assessments of inflammation are necessary in order to elucidate potential sensitive periods and mechanisms that link childhood adversity to later disease vulnerability.


Declining liver utilization for transplantation in the United States and the impact of donation after cardiac death

Eric Orman et al.
Liver Transplantation, January 2013, Pages 59-68

Worsening donor liver quality resulting in decreased organ utilization may be contributing to the recent decline in liver transplants nationally. We sought to examine trends in donor liver utilization and the relationship between donor characteristics and nonuse. We used the United Network for Organ Sharing database to review all deceased adult organ donors in the United States from whom at least 1 solid organ was transplanted into a recipient. Trends in donor characteristics were examined. Multivariate logistic regression was used to evaluate the association between donor characteristics and liver nonuse between 2004 and 2010. Population attributable risk proportions were determined for donor factors associated with nonuse. We analyzed 107,259 organ donors. The number of unused livers decreased steadily from 1958 (66% of donors) in 1988 to 841 (15%) in 2004 but then gradually increased to 1345 (21%) in 2010. The donor age, the body mass index (BMI), and the prevalence of diabetes and donation after cardiac death (DCD) all increased over time, and all 4 factors were independently associated with liver nonuse. DCD had the highest adjusted odds ratio (OR) for nonuse, and the odds increased nearly 4-fold between 2004 [OR = 5.53, 95% confidence interval (CI) = 4.57-6.70] and 2010 (OR = 21.31, 95% CI = 18.30-24.81). The proportion of nonuse attributable to DCD increased from 9% in 2004 to 28% in 2010. In conclusion, the proportion of donor livers not used has increased since 2004. Older donor age, greater BMI, diabetes, and DCD are all independently associated with nonuse and are on the rise nationally. Current trends may lead to significant declines in liver transplant availability.


Self-Forgiveness and Mortality in Late Life

Neal Krause & David Hayward
Social Indicators Research, March 2013, Pages 361-373

The purpose of this study is to see if older people who are able to forgive themselves have a lower mortality risk than older adults who are not able to forgive themselves. In addition, it is hypothesized that the relationship between self-forgiveness and mortality will be contingent upon the level of an older individual's education. More specifically, it is predicted that the potentially beneficial effects of self-forgiveness will be more evident among older people with more years of schooling. Data from a nationwide survey of older people provide support for this view. Self-forgiveness does not provide a mortality benefit for less educated elders. But as the level of educational attainment rises, self-forgiveness is associated with a progressively smaller mortality risk.


The Dose-Response of Time Served in Prison on Mortality: New York State, 1989-2003

Evelyn Patterson
American Journal of Public Health, March 2013, Pages 523-528

Objectives: I investigated the differential impact of the dose-response of length of stay on postprison mortality among parolees.

Methods: Using 1989-2003 New York State parole administrative data from the Bureau of Justice Statistics on state correctional facilities, I employed multinomial logistic regression analyses and formal demographic techniques that used the life table of the populations to deduce changes in life expectancy.

Results: Each additional year in prison produced a 15.6% increase in the odds of death for parolees, which translated to a 2-year decline in life expectancy for each year served in prison. The risk was highest upon release from prison and declined over time. The time to recovery, or the lowest risk level, was approximately two thirds of the time served in prison.

Conclusions: Incarceration reduces life span. Future research should investigate the pathways to this higher mortality and the possibilities of recovery.


The effect of compulsory schooling on health - evidence from biomarkers

Hendrik Jürges, Eberhard Kruk & Steffen Reinhold
Journal of Population Economics, April 2013, Pages 645-672

Using data from the Health Survey for England and the English Longitudinal Study on Ageing, we estimate causal effects of schooling on health. Our study complements earlier studies exploiting two nationwide increases in British compulsory school leaving age in 1947 and 1973, respectively, by using biological stress markers as measures of health outcomes in addition to self-reported measures. We find a strong positive correlation between education and health, both self-rated and measured by blood fibrinogen and C-reactive protein levels. However, causal effects estimates based on compulsory schooling changes are ambiguous and remain statistically insignificant.


The health returns to schooling - what can we learn from twins?

Petter Lundborg
Journal of Population Economics, April 2013, Pages 673-701

This paper estimates the health returns to schooling, using a twin design. For this purpose, I use data on monozygotic twins from the Midlife in the United States survey. The results suggest that completing high school improves health, as measured through self-reported health, chronic conditions, and exercise behavior, but that additional schooling does not lead to additional health gains. Controlling for certain early life factors that may vary within twin pairs does not alter the main conclusions of this paper.


Was What Ail'd Ya What Kill'd Ya?

Robert Fogel et al.
Economics & Human Biology, forthcoming

Making use of those Union Army veterans for whom death certificates are available, we compare the conditions with which they were diagnosed by Civil War pension surgeons to the causes of death on the certificates. We divide the data between those veterans who entered the pension system early because of war injuries and those who entered the pension system after the 1890 reform that made it available to many more veterans. We examine the correlation between specific medical conditions rated by the surgeons and death causes to gauge support for the hypothesis that death is attributable to something specific. We also examine the correlation between the accumulation of rated conditions to the length of time until death to gauge support for the "insult hypothesis." In general, we find support for both hypotheses. Examining the hazard ratios for dying of a specific condition, there is support for the idea that what ail'd ya' is what kill'd ya'.


Demographics and Burden on Caregivers of Seriously Wounded, Ill, and Injured Service Members

Eric Christensen & Yvette Clinton
Journal of Disability Policy Studies, March 2013, Pages 235-244

The media is replete with stories about the impact on families when they drastically alter their lives to provide care to a service member who is seriously wounded, ill, or injured (WII), though few studies have systematically examined these impacts. Using a 2008 survey of seriously WII service members, the authors found that 27% of caregivers provided an average of more than 40 hr of care per week, 64% of caregivers have provided care for more than a year, and 50% expected they may need to provide care over the long term. The probit and ordered probit results show that significant others (such as a spouse, fiancée, or girlfriend) bear a greater caregiving burden in both intensity and duration compared to other caregivers. The results also show that duration of caregiving for Reserve Component service members is greater than for Active Component service members.


The Effect of Hurricane Katrina on the Prevalence of Health Impairments and Disability among Adults in New Orleans: Differences by Age, Race, and Sex

Narayan Sastry & Jesse Gregory
Social Science & Medicine, forthcoming

We examined the effects of Hurricane Katrina on disability-related measures of health among adults from New Orleans, U.S.A., in the year after the hurricane, with a focus on differences by age, race, and sex. Our analysis used data from the American Community Survey to compare disability rates between the pre-Katrina population of New Orleans with the same population in the year after Katrina (individuals were interviewed for the study even if they relocated away from the city). The comparability between the pre- and post-Katrina samples was enhanced by using propensity weights. We found a significant decline in health for the adult population from New Orleans in the year after the hurricane, with the disability rate rising from 20.6% to 24.6%. This increase in disability reflected a large rise in mental impairments and, to a lesser extent, in physical impairments. These increases were, in turn, concentrated among young and middle-aged black females. Stress-related factors likely explain why young and middle-aged black women experienced worse health outcomes, including living in dwellings and communities that suffered the most damage from the hurricane, household breakup, adverse outcomes for their children, and higher susceptibility.


Are low wages risk factors for hypertension?

Paul Leigh & Juan Du
European Journal of Public Health, December 2012, Pages 854-859

Objective: Socio-economic status (SES) is strongly correlated with hypertension. But SES has several components, including income and correlations in cross-sectional data need not imply SES is a risk factor. This study investigates whether wages - the largest category within income - are risk factors.

Methods: We analysed longitudinal, nationally representative US data from four waves (1999, 2001, 2003 and 2005) of the Panel Study of Income Dynamics. The overall sample was restricted to employed persons age 25-65 years, n = 17 295. Separate subsamples were constructed of persons within two age groups (25-44 and 45-65 years) and genders. Hypertension incidence was self-reported based on physician diagnosis. Our study was prospective since data from three base years (1999, 2001, 2003) were used to predict newly diagnosed hypertension for three subsequent years (2001, 2003, 2005). In separate analyses, data from the first base year were used to predict time-to-reporting hypertension. Logistic regressions with random effects and Cox proportional hazards regressions were run.

Results: Negative and strongly statistically significant correlations between wages and hypertension were found both in logistic and Cox regressions, especially for subsamples containing the younger age group (25-44 years) and women. Correlations were stronger when three health variables - obesity, subjective measures of health and number of co-morbidities - were excluded from regressions. Doubling the wage was associated with 25-30% lower chances of hypertension for persons aged 25-44 years.

Conclusions: The strongest evidence for low wages being risk factors for hypertension among working people were for women and persons aged 25-44 years.


Childhood emotional functioning and the developmental origins of cardiovascular disease risk

Allison Appleton et al.
Journal of Epidemiology & Community Health, forthcoming

Background: Dysregulated emotional functioning has been linked with higher cardiovascular disease (CVD) risk among adults. Early life experiences may influence the development of adulthood CVD, but few studies have examined whether potential damaging effects of dysregulated emotional function begin earlier in life. Therefore, we examined associations of child emotional functioning and the 10-year risk of developing CVD in midlife.

Methods: We studied 377 adult offspring (mean age=42.2) of Collaborative Perinatal Project participants, a US cohort of pregnant women enrolled in 1959-1966. Three measures of child emotional functioning derived from psychologist ratings of behaviour at 7 years of age were examined: distress proneness, attention and inappropriate self-regulation. Adulthood 10-year CVD risk was calculated with the validated Framingham general CVD risk algorithm. Gender-specific multiple regression models assessed associations of childhood emotion and adulthood CVD risk independent of covariates measured across the life course. Potential mediators of the associations were also examined.

Results: Women had 31% higher CVD risk per SD increase in childhood distress proneness (p=0.03) and 8% reduced risk per SD increase in attention (p=0.09). For men, each SD increase in childhood distress proneness was associated with 17% higher CVD risk (p=0.02). Associations were partly explained by adulthood body mass index and depressive symptoms in women but not in men. Inappropriate self-regulation was not associated with CVD risk.

Conclusions: Several aspects of childhood emotional functioning was associated with adulthood CVD risk, particularly for women. As such, primary prevention of CVD may be associated with addressing early life emotional functioning.


Risk of Total and Aggressive Prostate Cancer and Pesticide Use in the Agricultural Health Study

Stella Koutros et al.
American Journal of Epidemiology, 1 January 2013, Pages 59-74

Because pesticides may operate through different mechanisms, the authors studied the risk of prostate cancer associated with specific pesticides in the Agricultural Health Study (1993-2007). With 1,962 incident cases, including 919 aggressive prostate cancers among 54,412 applicators, this is the largest study to date. Rate ratios and 95% confidence intervals were calculated by using Poisson regression to evaluate lifetime use of 48 pesticides and prostate cancer incidence. Three organophosphate insecticides were significantly associated with aggressive prostate cancer: fonofos (rate ratio (RR) for the highest quartile of exposure (Q4) vs. nonexposed = 1.63, 95% confidence interval (CI): 1.22, 2.17; Ptrend < 0.001); malathion (RR for Q4 vs. nonexposed = 1.43, 95% CI: 1.08, 1.88; Ptrend = 0.04); and terbufos (RR for Q4 vs. nonexposed = 1.29, 95% CI: 1.02, 1.64; Ptrend = 0.03). The organochlorine insecticide aldrin was also associated with increased risk of aggressive prostate cancer (RR for Q4 vs. nonexposed = 1.49, 95% CI: 1.03, 2.18; Ptrend = 0.02). This analysis has overcome several limitations of previous studies with the inclusion of a large number of cases with relevant exposure and detailed information on use of specific pesticides at 2 points in time. Furthermore, this is the first time specific pesticides are implicated as risk factors for aggressive prostate cancer.


Eggs versus Chewable Vitamins: Which Intervention Can Increase Nutrition and Test Scores in Rural China?

Max Kleiman-Weiner et al.
China Economic Review, March 2013, Pages 165-176

Despite growing wealth and a strengthening commitment from the government to provide quality education, a significant share of students across rural China still have inadequate access to micronutrient-rich regular diets. Such poor diets can lead to nutritional problems, such as iron-deficiency anemia, that can adversely affect attention and learning in school. Large scale policies in Northwestern China have attempted to tackle these nutritional problems using eggs. The overall goal of this paper is to assess the impact of the government's egg distribution program by comparing the effect on anemia rates of an intervention that gives students an egg per day versus an intervention that gives students a chewable vitamin per day. We will also assess whether either intervention leads to improved educational performance among students in poor areas of rural China. To meet this goal, we report on the results of a randomized controlled trial (RCT) involving over 2,600 fourth grade students from 70 randomly-chosen elementary schools in 5 of the poorest counties in Gansu Province in China's poor Northwest region. The design called for random assignment of schools to one of two intervention groups, or a control group with no intervention. One intervention provided a daily chewable vitamin, including 5 milligrams of iron. The other mimicked the government policy by providing a daily egg. According to the findings of the paper, in the schools that received the chewable vitamins, hemoglobin (Hb) levels rose by more than 2 g/L (over 0.2 standard deviations). The standardized math test scores of students in these schools also improved significantly. In schools that received eggs, there was no significant effect on Hb levels or math test scores. Overall, these results should encourage China's Ministry of Education (MOE) to look beyond eggs when tackling nutritional problems related to anemia in an education setting.


Antibiotic Resistance Is Prevalent in an Isolated Cave Microbiome

Kirandeep Bhullar et al.
PLoS ONE, April 2012

Antibiotic resistance is a global challenge that impacts all pharmaceutically used antibiotics. The origin of the genes associated with this resistance is of significant importance to our understanding of the evolution and dissemination of antibiotic resistance in pathogens. A growing body of evidence implicates environmental organisms as reservoirs of these resistance genes; however, the role of anthropogenic use of antibiotics in the emergence of these genes is controversial. We report a screen of a sample of the culturable microbiome of Lechuguilla Cave, New Mexico, in a region of the cave that has been isolated for over 4 million years. We report that, like surface microbes, these bacteria were highly resistant to antibiotics; some strains were resistant to 14 different commercially available antibiotics. Resistance was detected to a wide range of structurally different antibiotics including daptomycin, an antibiotic of last resort in the treatment of drug resistant Gram-positive pathogens. Enzyme-mediated mechanisms of resistance were also discovered for natural and semi-synthetic macrolide antibiotics via glycosylation and through a kinase-mediated phosphorylation mechanism. Sequencing of the genome of one of the resistant bacteria identified a macrolide kinase encoding gene and characterization of its product revealed it to be related to a known family of kinases circulating in modern drug resistant pathogens. The implications of this study are significant to our understanding of the prevalence of resistance, even in microbiomes isolated from human use of antibiotics. This supports a growing understanding that antibiotic resistance is natural, ancient, and hard wired in the microbial pangenome.

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