Saturday, August 29, 2009

How Much Radiation Comes from Medical x-rays?

Volume 361:849-857 August 27, 2009 Number 9

Exposure to Low-Dose Ionizing Radiation from Medical Imaging Procedures
Reza Fazel, M.D., M.Sc., Harlan M. Krumholz, M.D., S.M., Yongfei Wang, M.S., Joseph S. Ross, M.D., Jersey Chen, M.D., M.P.H., Henry H. Ting, M.D., M.B.A., Nilay D. Shah, Ph.D., Khurram Nasir, M.D., M.P.H., Andrew J. Einstein, M.D., Ph.D., and Brahmajee K. Nallamothu, M.D., M.P.H.

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 by Lauer, M. S.

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Background The growing use of imaging procedures in the United States has raised concerns about exposure to low-dose ionizing radiation in the general population.

Methods We identified 952,420 nonelderly adults (between 18 and 64 years of age) in five health care markets across the United States between January 1, 2005, and December 31, 2007. Utilization data were used to estimate cumulative effective doses of radiation from imaging procedures and to calculate population-based rates of exposure, with annual effective doses defined as low (≤3 mSv), moderate (>3 to 20 mSv), high (>20 to 50 mSv), or very high (>50 mSv).

Results During the study period, 655,613 enrollees (68.8%) underwent at least one imaging procedure associated with radiation exposure. The mean (±SD) cumulative effective dose from imaging procedures was 2.4±6.0 mSv per enrollee per year; however, a wide distribution was noted, with a median effective dose of 0.1 mSv per enrollee per year (interquartile range, 0.0 to 1.7). Overall, moderate effective doses of radiation were incurred in 193.8 enrollees per 1000 per year, whereas high and very high doses were incurred in 18.6 and 1.9 enrollees per 1000 per year, respectively. In general, cumulative effective doses of radiation from imaging procedures increased with advancing age and were higher in women than in men. Computed tomographic and nuclear imaging accounted for 75.4% of the cumulative effective dose, with 81.8% of the total administered in outpatient settings.

Conclusions Imaging procedures are an important source of exposure to ionizing radiation in the United States and can result in high cumulative effective doses of radiation.

Friday, August 28, 2009

Cannabis Improves Respiratory Capacity

Effects of cannabis on lung function: a population-based cohort study

R.J. Hancox 1*, R. Poulton 1, M. Ely 1, D. Welch 1, D.R. Taylor 2, C.R. McLachlan 1, J.M. Greene 3, T.E. Moffitt 4, A. Caspi 4, M.R. Sears 3

1 Dunedin Multidisciplinary Health and Development Research Unit, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
2 Dept of Medical and Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
3 Firestone Institute for Respiratory Health, St. Joseph's Healthcare and Dept of Medicine, McMaster University, Hamilton, Ontario, Canada
4 Depts of Psychology & Neuroscience and Psychiatry & Behavioral Sciences, and Institute for Genome Sciences and Policy, Duke University, Durham, North Carolina, USA; and MRC Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, UK

* To whom correspondence should be addressed. E-mail:


The effects of cannabis on lung function remain unclear and may be different to tobacco. We compared the associations between use of these substances and lung function in a population-based cohort (n=1037).

Cannabis and tobacco use were reported at ages 18, 21, 26, and 32 years. Spirometry, plethysmography, and carbon monoxide transfer factor were measured at age 32. Associations between lung function and exposure to each substance were adjusted for exposure to the other substance.

Cumulative cannabis use was associated with higher forced vital capacity, total lung capacity, functional residual capacity, and residual volume. Cannabis was also associated with higher airways resistance but not with forced expiratory volume in 1 second, forced expiratory ratio, or transfer factor. These findings were similar amongst those who did not smoke tobacco. By contrast, tobacco use was associated with lower forced expiratory volume in 1 second, lower forced expiratory ratio, lower transfer factor, and higher static lung volumes, but not with airways resistance.

Cannabis appears to have different effects on lung function to those of tobacco. Cannabis use was associated with higher lung volumes suggesting hyperinflation and increased large-airways resistance, but there was little evidence for airflow obstruction or impairment of gas transfer.

Thursday, August 27, 2009

Low Levels of Particle Air Pollution Effect Children with Asthma

. Dales, L. Chen, A. M. Frescura, L. Liu, and P. J. Villeneuve
Eur Respir J 2009 34: 316-323.

1 University of Ottawa, 2 Ottawa Hospital Research Insitute, 3 Air Health Effects Research Section, Biostatistics and Epidemiology Division, Environmental Health Science and Research Bureau, Health Canada, and 4 Immunization and Respiratory Infections Division, Public Health Agency of Canada, Ottawa, ON, Canada.

CORRESPONDENCE: R. Dales, Air Health Effects Research Section, Biostatistics and Epidemiology Division, Environmental Health Science and Research Bureau, Health Canada, 3rd Floor, Room 3-039, P.L. 4903B, 269 Laurier Avenue W, Ottawa, K1A 0K9, ON, Canada. E-mail:

Keywords: Air pollution, children, environment, lung function

Received: September 9, 2008
Accepted February 5, 2009

Urban air pollution has been associated with morbidity but little information exists on how it affects diurnal variation of lung function in children with asthma. The purpose of this study was to investigate the acute effects of traffic-related pollution on lung function among children with asthma.

We recorded morning and evening forced expiratory volume in 1 s (FEV1) for 28 consecutive days in 182 elementary schoolchildren with physician-diagnosed asthma, and monitored ambient hourly air pollution concentrations.

An interquartile range (IQR) increase (6.0 µg·m–3) in the previous 24-h (20:00 h to 20:00 h) mean concentration of fine particulate matter 2.5 µm in diameter (PM2.5) was associated with a 0.54% (95% confidence interval (CI) 0.06–1.02) decrease in bedtime FEV1 (p = 0.027). This association persisted in two-pollutant models with ozone, nitrogen dioxide and sulphur dioxide. An IQR increase in mean daytime (08:00 h to 20:00 h) PM2.5 of 6.5 µg·m–3 was associated with a 0.73% (95% CI 0.10–1.37) decrease in FEV1 over the course of the day expressed as 100x(FEV1 bedtime – FEV1 morning)/FEV1 morning (p = 0.024).

This study suggests that, in children with asthma, relatively low concentrations of urban air pollution worsen lung function over a short period of time, even within a day. Of the pollutants measured, PM2.5 appears to be the most important.

Wednesday, August 26, 2009

What's All This Posting on Non Occupational Effects About?

BrooklynDodger(s) comments: All the time, epidemiologists with cohorts of opportunity examine associations of demographic variables with mortality, because they can. Nevertheless, the accumulation of these associations without biological hypotheses make for nice conversations make for interesting conversations about causes underlying more clearly focused occupational studies. The previous post quoted results of associations of earlier marriage among men, and shorter or no divorce among women with increased mortality. What hypothesis about psychosocial environment and what mechanism could be drawn? Can't think of one.,

Tuesday, August 25, 2009

Does Marriage Promote Longer Life? No clear answer.

BrooklynDodger(s) comment: The pattern only confuses. Married late for men, and being divorced a long time for women seems to predict health.

American Journal of Epidemiology 2009 170(5):546-555

Marital Trajectories and Mortality Among US Adults

Matthew E. Dupre, Audrey N. Beck and Sarah O. Meadows

Correspondence to Dr. Matthew E. Dupre, Social Science Research Institute, Duke University, P.O. Box 90420, 2024 West Main Street, Durham, NC (e-mail:

Received for publication May 19, 2008. Accepted for publication April 27, 2009.

More than a century of empirical evidence links marital status to mortality. However, the hazards of dying associated with long-term marital trajectories and contributing risk factors are largely unknown. The authors used 1992–2006 prospective data from a cohort of US adults to investigate the impact of current marital status, marriage timing, divorce and widow transitions, and marital durations on mortality. Multivariate hazard ratios were significantly higher for adults currently divorced and widowed, married at young ages (≤18 years), who accumulated divorce and widow transitions (among women), and who were divorced for 1–4 years. Results also showed significantly lower risks of mortality for men married after age 25 years compared with on time (ages 19–25 years) and among women experiencing ≥10 years of divorce and ≥5 years of widowhood relative to those without exposure to these statuses. For both sexes, accumulation of marriage duration was the most robust predictor of survival. Results from risk-adjusted models indicated that socioeconomic resources, health behaviors, and health status attenuated the associations in different ways for men and women. The study demonstrates that traditional measures oversimplify the relation between marital status and mortality and that sex differences are related to a nexus of marital experiences and associated health risks.

Monday, August 24, 2009

All Work and No Play Makes Jack a Dull Boy

Long Working Hours and Cognitive Function

The Whitehall II Study

Marianna Virtanen, Archana Singh-Manoux, Jane E. Ferrie, David Gimeno, Michael G. Marmot,Marko Elovainio, Markus Jokela, Jussi Vahtera, and Mika Kivima¨

This study examined the association between long working hours and cognitive function in middle age. Data were collected in 1997–1999 (baseline) and 2002–2004 (follow-up) from a prospective study of 2,214 British civil servants who were in full-time employment at baseline and had data on cognitive tests and covariates. A battery of cognitive tests (short-term memory, Alice Heim 4-I, Mill Hill vocabulary, phonemic fluency, and semantic fluency)
were measured at baseline and at follow-up. Compared with working 40 hours per week at most, working more than 55 hours per week was associated with lower scores in the vocabulary test at both baseline and follow-up. Long working hours also predicted decline in performance on the reasoning test (Alice Heim 4-I). Similar results were obtained by using working hours as a continuous variable; the associations between working hours and cognitive function were robust to adjustments for several potential confounding factors including age, sex, marital status, education, occupation, income, physical diseases, psychosocial factors, sleep disturbances, and health risk behaviors. This study shows that long working hours may have a negative effect on cognitive performance in middle age.

Sunday, August 23, 2009

BPA extrapolation

BrooklynDodger(s) comments: The highlighted sentence appears to contradict itself. Were the reviewers asleep? Still, a mechanism for greater sensitivity of younger organisms.

Toxicology Letters
Bisphenol A levels in blood depend on age and exposure
Pages 32-40
Hans Mielke, Ursula Gundert-Remy

Federal Institute for Risk Assessment/Bundesinstitut für Risikobewertung (BfR), Thielallee 88-92, D-14195 Berlin, Germany

Received 24 April 2009;
revised 17 June 2009;
accepted 19 June 2009.
Available online 26 June 2009.


We present two approaches to estimate blood concentrations of Bisphenol A (BPA). Simple kinetic principles were applied to calculate steady state plasma concentrations. A physiologically based model was used to simulate the blood concentration time profile in several age groups exploring the influence of not yet fully developed metabolic capacity on the blood concentrations in the newborn.

Both approaches gave concordant results and are in excellent agreement with experimental results [Völkel, W., Colnot, T., Csanady, G.A., Filser, J.G., Dekant, W., 2002. Metabolism and kinetics of bisphenol A in humans at low doses following oral administration. Chem. Res. Toxicol. 15, 1281–1287]. The predictions also agree with published results obtained with a different physiologically based model.

According to model simulations, BPA is present in the blood of the normal population at concentrations several orders of magnitude lower than most measurements reported in the literature. At the same external exposure level, the newborn is predicted to have 3 times greater blood concentration than the adult. This is due to the not yet fully developed glucuronidation activity in the newborn, not fully compensated by the unimpaired sulfation pathway. For the highest measured external BPA exposure, the predicted blood concentrations of 2.6 pg/ml (steady state concentration) and 8.2 pg/ml (peak concentration) in the adult are lower than the in vitro concentrations at which inhibiting adiponectin release from human adipocytes and stimulation of β-cell production and secretion were observed.

Saturday, August 22, 2009

Journal Issue Devoted to Prions

Journal of Toxicology and Environmental Health, Part A: Current Issues Volume 72 Issue 17 & 18 (,email) is now available online at informaworld (

Special Issue:Prion Research in Perspective

REACHING for protection

BrooklynDodger(s) comments: REACH requires manufacturers to calculate DNELS, essentially by the general method by which EPA calculates RfC's for IRIS. That will generate a ton of DNELs. RfC's for most chemicals of occupational importance are way lower than PEL's, REL's or TLV's. This paper comments that REACH protocols are riskier than IRIS protocols.

Assessment factors for extrapolation from short-time to chronic exposure—Are the REACH guidelines adequate?

Pages 16-22
Katarzyna Malkiewicz, Sven Ove Hansson, Christina Rudén

Due to the relative scarcity of long-term toxicity data, assessment factors for extrapolation from relatively short to chronic exposures have an important role in the risk assessment of chemicals. A recent REACH guidance document includes recommended default assessment factors that cover subacute–subchronic, subchronic–chronic, and subacute–chronic extrapolations. The recommended assessment factors are smaller than in most previous proposals, since they are calibrated to achieve central estimates (50th percentile of the target distribution) rather than a higher percentile such as the 95th, as has been more common. These assessment factors are nevertheless presented as representing a “widely agreed level of conservatism”, a statement that may lead to misunderstandings of what is achieved by using them in a risk assessment. Assessment factors have been based on evidence from animal studies with different designs, in particular with focus on different endpoints. Our re-analysis of experimental data shows that using mortality as an endpoint leads to smaller assessment factors than if the factors are derived from corresponding ratios for non-lethal toxicity.

Friday, August 21, 2009

Whole Body Vibration Exposure to Motorcyle Riders Exceeds Recommended Limits

BrooklynDodger(s): Whole body vibration effects are less well defined than segmental (arm and hand) vibration. But effect many more organ systems. The study reveals that motorcycles pose a risk almost unanimously.

Whole-body vibration exposure experienced by motorcycle riders ­ An evaluation acccording to ISO 2631-1 and ISO 2631-5 standards

Pages 708-718 Hsieh-Ching Chen, Wei-Chyuan Chen, Yung-Ping Liu, Chih-Yong Chen, Yi-Tsong Pan

Whole-body vibration exposure experienced by motorcycle riders – An evaluation according to ISO 2631-1 and ISO 2631-5 standards

Hsieh-Ching Chena, Corresponding Author Contact Information, E-mail The Corresponding Author, Wei-Chyuan Chena, Yung-Ping Liua, Chih-Yong Chenb and Yi-Tsong Panb

aDepartment of Industrial Engineering and Management, Chaoyang University of Technology, No. 168 Jifong E. Rd., Wufong, Taichung County 41349, Taiwan

bInstitute of Occupational Safety and Health, Council of Labor Affairs, Executive Yuan, No. 99, Lane 407, Hengke Rd., Sijhih, Taipei County 22143, Taiwan

Received 18 December 2007;
revised 14 March 2009;
accepted 24 May 2009.
Available online 21 June 2009.


Riders of twelve motorcycles, comprising 6 full-scale motorbikes and 6 motor-scooters, and 5 sedan vehicles, performed test runs on a 20.6 km paved road composed of 5 km, 5 km, and 10.6 km of rural, provincial and urban routes, respectively. Each test run of motorcycle was separately performed under speed limits of 55 km/h and 40 km/h. Tri-axial accelerations of whole-body vibration (WBV) were obtained by using a seat pad and a portable data logger, and the driver's view was videotaped with a portable media recorder. Root mean square (RMS) acceleration, 8-h estimated vibration dose value (VDV(8)) and 8-h estimated daily dose of static compression dose (Sed) were determined from the collected data in accordance with ISO 2631-1 and ISO 2631-5 standards. Experimental results indicate that the WBV values of the sedan vehicle drivers have low RMS, VDV(8) and Sed values (RMS 0.27–0.32 m/s2; VDV(8) 6.3–8.3 m/s1.75; Sed 0.21–0.26 MPa). However, over 90% of the motorcycle riders had VDV(8) (mean 23.5 m/s1.75) exceeding the upper boundary of health guidance caution zone (17 m/s1.75) recommended by ISO 2631-1, or had Sed (mean 1.17 MPa) exceeding the value associated with a high probability of adverse health effects (0.8 MPa) recommended by ISO 2631-5. Over 50% of the motorcycle riders reached these boundary values for VDV and Se in less than 2 h. The WBV exposure levels of the full-scale motorbikes riders and motor-scooter riders were not significantly different. However, the RMS and VDV(8) values of motorcycle riders indicate significant roadway effect (p <>Sed values indicate significant speed limit effect (p <>

Thursday, August 20, 2009

Falls and age

BrooklynDodger(s) comment: Need clear guidance on living arrangements for older results. Often the fall triggers the cascade of much worse effects.

During 2007, the annual rate of nonfatal, medically attended fall injury episodes was 43 per 1,000 population. Adults aged ≥75 years had higher rates of these episodes compared with persons aged <65>

SOURCE: Adams PF, Barnes PM, Vickerie JL. Summary health statistics for the U.S. population: National Health Interview Survey, 2007. Vital Health Stat 2008;10(238). Available at

August 14, 2009 / 58(31);858

Wednesday, August 19, 2009

Impaired Driving - Still Barking up the Wrong Tree

August 14, 2009 / 58(31);856

Notice to Readers: National Labor Day Drunk Driving Enforcement Crackdown --- August 21--September 7, 2009

In 2007, a total of 12,998 persons died in motor-vehicle crashes in which at least one driver had a blood alcohol concentration of >0.08 g/dL, above the legal limit for drivers in the United States. These alcohol-impaired--driving fatalities accounted for 32% of all motor-vehicle traffic fatalities in 2007 (1).

BrooklynDodger(s) comment: It's easy to blame the toll of vehicle related injuries on the guilty victims, emphasizing drunk or substance abused driving. Drinking and driving is confounded by not wearing seat belts, driving late at night on the weekend, probably speeding, (and being a male under 25, but that's really hard to intervene on) all of which add to the 32% fraction of traffic fatalities attributed solely to drinking. NHTSA needs to think more about intervening on the causes of risk behavior and intervening on that. What about a drowsy driving enforcement day, or promulgating a warning on driving consistent with the recommendations for truck drivers (which aren't protective enough)?