SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Epidemiology (Cambridge, Mass.)

424

After the Great East Japan Earthquake and Tsunami in March 2011, radioactive elements were released from the Fukushima Daiichi Nuclear Power Plant. Based on prior knowledge, concern emerged about whether an increased incidence of thyroid cancer among exposed residents would occur as a result.

Concepts: Sellafield, Electricity generation, Nuclear safety, Japan, Nuclear power, Nuclear fission, Chernobyl disaster, Uranium

176

Multiple studies of ovarian cancer and genital talc use have led only to consensus about possible carcinogenicity. Seeking greater clarity, we examined this association in 2041 cases with epithelial ovarian cancer and 2100 age-and-residence-matched controls.

Concepts: Metastasis, Hereditary nonpolyposis colorectal cancer, Oncology, Talc, BRCA2, Epidemiology, Case-control study, Ovarian cancer

57

Biomass burning is an important source of ambient fine particulate air pollution (PM2.5) in many regions of the world.

Concepts: Infarction, Troponin, Dust, Smog, Atherosclerosis, Air pollution, Particulate, Myocardial infarction

39

BACKGROUND:: In recent years (2000-2007), ambient levels of fine particulate matter (PM2.5) have continued to decline as a result of interventions, but the decline has been at a slower rate than previous years (1980-2000). Whether these more recent and slower declines of PM2.5 levels continue to improve life expectancy and whether they benefit all populations equally is unknown. METHODS:: We assembled a data set for 545 U.S. counties consisting of yearly county-specific average PM2.5, yearly county-specific life expectancy, and several potentially confounding variables measuring socioeconomic status, smoking prevalence, and demographic characteristics for the years 2000 and 2007. We used regression models to estimate the association between reductions in PM2.5 and changes in life expectancy for the period from 2000 to 2007. RESULTS:: A decrease of 10 μg/m in the concentration of PM2.5 was associated with an increase in mean life expectancy of 0.35 years (SD = 0.16 years, P = 0.033). This association was stronger in more urban and densely populated counties. CONCLUSIONS:: Reductions in PM2.5 were associated with improvements in life expectancy for the period from 2000 to 2007. Air pollution control in the last decade has continued to have a positive impact on public health.

Concepts: Dust, Population density, Smog, United States, Population, Demography, Particulate, Air pollution

34

Although air pollution’s short-term effects are well understood to be marked and preventable, its acute neuropsychological effects have, to our knowledge, not yet been studied. We aim to examine the association between daily variation in traffic-related air pollution and attention.

Concepts: School terminology, Junior school, School, Primary education, Primary school

29

Cohort studies can be biased by unmeasured confounding. We propose a hybrid ecologic-epidemiologic design called the trend-in-trend design, which requires a strong time-trend in exposure, but is unbiased unless there are unmeasured factors affecting outcome for which there are time-trends in prevalence that are correlated with time-trends in exposure across strata with different exposure trends. Thus, the conditions under which the trend-in-trend study is biased are a subset of those under which a cohort study is biased. The trend-in-trend design first divides the study population into strata based on the cumulative probability of exposure given covariates, which effectively stratifies on time-trend in exposure, provided there is a trend. Next, a covariates-free maximum likelihood model estimates the odds ratio (OR) using data on exposure prevalence and outcome frequency within cumulative probability of exposure strata, across multiple periods. In simulations, the trend-in-trend design produced ORs with negligible bias in the presence of unmeasured confounding. In empiric applications, trend-in-trend reproduced the known positive association between rofecoxib and myocardial infarction (observed OR: 1.2, 95% confidence interval: 1.1, 1.4), and known null associations between rofecoxib and severe hypoglycemia [OR = 1.1 (0.92, 1.3)] and non-vertebral fracture [OR = 0.84 (0.64, 1.1)]. The trend-in-trend method may be useful in settings where there is a strong time-trend in exposure, such as a newly approved drug or other medical intervention.

Concepts: Normal distribution, Relative risk, Study design, Clinical trial, Epidemiology, Experimental design, Cohort study, Scientific method

28

BACKGROUND:: Studies of the health effects of non-asbestiform asbestos minerals remain inconclusive. Nephrite is a type of non-asbestiform tremolite mineral. We assessed the risk for pulmonary fibrosis in workers who process nephrite. METHODS:: A cross-sectional study that included 344 stone workers and their families was undertaken in Taiwan in 2010. The diagnostic criteria for pulmonary fibrosis included (1) radiographic fibrosis profusion of 1/1 or greater and (2) audible lung crackles confirmed by physician. The nephrite samples were analyzed using polarized light and transmission electron microscopy combined with selected-area electron diffraction and energy-dispersive x-ray spectroscopy. RESULTS:: After excluding 16 subjects with histories of tuberculosis or previous employment in metal casting and welding, as well as 23 family members who had not worked in the stone industry, we analyzed 305 subjects. Processing nephrite increased the risk for pulmonary fibrosis (odds ratio = 2.8 [95% confidence interval = 1.0-9.9] and unchanged after adjustment for age and smoking). Bulk sample analyses showed that the nephrite is a tremolite mineral composed of both asbestiform and non-asbestiform components. The cat’s-eye nephrite had the highest asbestiform fibrous content, and the average length and aspect ratio of elongated mineral particles were the highest of all the nephrite types. Compared with workers processing other types of nephrite, workers processing cat’s-eye nephrite had the highest risk for pulmonary fibrosis. CONCLUSION:: Processing non-asbestiform tremolite mineral may increase the risk for pulmonary fibrosis. Medical monitoring is warranted for workers with such exposure.

Concepts: Amphibole, X-ray, Aspect ratio, Silicate minerals, Scanning electron microscope, Transmission electron microscopy, Electron, Asbestos

27

Unconventional natural gas development has expanded rapidly. In Pennsylvania, the number of producing wells increased from 0 in 2005 to 3,689 in 2013. Few publications have focused on unconventional natural gas development and birth outcomes.

Concepts: Natural gas, Maize

26

BACKGROUND:: Adherence to a Mediterranean diet has been associated with lower risk of various age-related diseases including dementia. Although narrative reviews have been published, no systematic review has synthesized studies on the association between Mediterranean diet adherence and cognitive function or dementia. METHODS:: We conducted a systematic review of 11 electronic databases (including Medline) of published articles up to January 2012. Reference lists, selected journal contents, and relevant websites were also searched. Study selection, data extraction, and quality assessment were performed independently by two reviewers using predefined criteria. Studies were included if they examined the association between a Mediterranean diet adherence score and cognitive function or dementia. RESULTS:: Twelve eligible papers (11 observational studies and one randomized controlled trial) were identified, describing seven unique cohorts. Despite methodological heterogeneity and limited statistical power in some studies, there was a reasonably consistent pattern of associations. Higher adherence to Mediterranean diet was associated with better cognitive function, lower rates of cognitive decline, and reduced risk of Alzheimer disease in nine out of 12 studies, whereas results for mild cognitive impairment were inconsistent. CONCLUSIONS:: Published studies suggest that greater adherence to Mediterranean diet is associated with slower cognitive decline and lower risk of developing Alzheimer disease. Further studies would be useful to clarify the association with mild cognitive impairment and vascular dementia. Long-term randomized controlled trials promoting a Mediterranean diet may help establish whether improved adherence helps to prevent or delay the onset of Alzheimer disease and dementia.

Concepts: Aging-associated diseases, Pharmaceutical industry, Clinical trial, Cognition, Experimental design, Epidemiology, Randomized controlled trial, Alzheimer's disease

23

We collected detailed activity paths of urban youth to investigate the dynamic interplay between their lived experiences,time spent in different environments,and risk of violent assault.

Concepts: Violence, Terrorism, Domestic violence