<?xml version="1.0" encoding="utf-8"?>
<recommendedContent xmlns="http://api.mspoke.com">
    <recommendedItem id="20100101_19_425"
                     title="AAN: Industrial Cleaner Again Tied to Parkinson Risk (CME/CE)"
                     score="0.014"
                     href="http://www.medpagetoday.com/MeetingCoverage/AAN/tb/18338?impressionId=1265798815900"
                     
      TORONTO  --  The degreasing agent trichloroethylene (TCE) has been linked to increased rates of Parkinson&apos;s disease among industrial workers in yet another study, this time involving a large, well-studied group of World War II veterans.&lt;br&gt;
&lt;br&gt;Parkinson&apos;s disease developed in individuals with occupational exposure to TCE at more than five times the rate seen in those without such exposure (odds ratio 5.5, 95% CI 1.02 to 30), reported Samuel Goldman, MD, of the Parkinson&apos;s Institute in Sunnyvale, Calif.&lt;br&gt;
&lt;br&gt;Goldman described the research in a phone interview with &lt;em&gt;MedPage Today&lt;/em&gt;. It&apos;s scheduled for presentation here in April at the American Academy of Neurology&apos;s annual meeting.&lt;br&gt;
&lt;br&gt;A previous study in 2008 had fingered TCE as the most likely culprit behind a cluster of Parkinson&apos;s disease cases afflicting workers at a single industrial plant. (See &lt;a href=&quot;http://www.medpagetoday.com/Geriatrics/ParkinsonsDisease/7894&quot; mce_href=&quot;http://www.medpagetoday.com/Geriatrics/ParkinsonsDisease/7894&quot; target=&quot;_blank&quot;&gt;Trichloroethylene Implicated as Risk for Parkinsonism&lt;/a&gt;)&lt;p&gt;&lt;/p&gt;
&lt;p&gt;Also, Goldman said, animal studies have found that TCE is selectively toxic to nigral dopaminergic neurons, the same type of nerve cell that progressively dies off in Parkinson&apos;s disease. He said the chemical&apos;s activity in rodent brains is very similar to that of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), a dopaminergic neurotoxin commonly used to simulate Parkinson&apos;s disease in preclinical research.&lt;/p&gt;
&lt;p&gt;Goldman said the new study was the first population-based analysis to link TCE to the disease.&lt;/p&gt;
&lt;p&gt;It focused on 198 twin pairs in the National Academy of Sciences-National Research Council&apos;s World War II Twins Cohort, which comprises some 16,000 twin pairs overall.&lt;/p&gt;
&lt;p&gt;Members of the all-male cohort, who were born from 1917 to 1927 and served in the war, have been followed since the 1960s. Occupational histories for participants are available along with medical records from the VA healthcare system.&lt;/p&gt;
&lt;p&gt;In those pairs chosen for the current study, records showed that one twin had developed Parkinson&apos;s disease and the other had not. This design largely eliminates genetics as a confounding factor in the analysis.&lt;/p&gt;
&lt;p&gt;Goldman explained that occupational histories for each participant were reviewed by a blinded industrial hygienist and a preventive medicine physician to identify likely exposures to TCE and four other industrial chemicals: xylene, toluene, carbon tetrachloride, and tetrachloroethylene.&lt;/p&gt;
&lt;p&gt;As a single source of exposure, only TCE was significantly associated with development of Parkinson&apos;s disease, Goldman said.&lt;/p&gt;
&lt;p&gt;People working as aircraft mechanics, machinists, plumbers, and electricians likely had regular exposure to TCE, Goldman said. The chemical was commonly used as a &quot;spot&quot; cleaner to remove grease and oils from metal surfaces. It was also used for a time as a dry cleaning solvent, although tetrachloroethylene was more common for that purpose.&lt;/p&gt;
&lt;p&gt;Goldman said no increased risk was seen with xylene or toluene, but there were near-significant trends toward increased Parkinson&apos;s disease risk from carbon tetrachloride and tetrachloroethylene: &lt;ul&gt; &lt;li&gt;Carbon tetrachloride: OR 2.8 (95% CI 0.97 to 7.8)&lt;/li&gt; &lt;li&gt;Tetrachloroethylene: OR 9.0 (95% CI 0.78 to 103)&lt;/li&gt; &lt;/ul&gt;&lt;/p&gt;
&lt;p&gt;Twins exposed to either TCE or tetrachloroethylene were at significantly increased risk, with an odds ratio of 8.1 (95% CI 1.43 to 43) relative to individuals with no exposure to either chemical.&lt;/p&gt;
&lt;p&gt;Goldman said the analysis also examined whether duration of exposure was associated with increased risk. He said the results were in the same pattern as for the yes-no exposure analysis, but the findings were very uncertain because of the relatively small sample size.&lt;/p&gt;
&lt;p&gt;Occupational histories were available for only 99 of the 198 discordant twin pairs and some of the information was obtained by proxy rather than from the participant himself.&lt;/p&gt;
&lt;p&gt;Because of the wide confidence intervals even for the yes-no exposure analysis, the findings need confirmation in a larger study, he said, noting that the best approach would be a cohort study involving people with known, long-term exposure to TCE, compared with well-chosen controls.&lt;/p&gt;
&lt;p&gt;&quot;The study wouldn&apos;t have to be large,&quot; Goldman said. He estimated that 1,000 to 2,000 participants would be adequate to determine if the connection to Parkinson&apos;s disease is real.&lt;/p&gt;
&lt;div style=&quot;float:left;border-style:solid;border-width:1px;border-color:#8dabbc;font-family:arial;font-size:12px;background-color:#DBE9F2;padding:5px;&quot;&gt;&lt;p&gt;The study was funded by the National Institute of Neurological Disorders and Stroke, the Valley Foundation, and the James and Sharron Clark Family Fund.&lt;/p&gt;&lt;p&gt;No potential conflicts of interest were reported.&lt;/p&gt;&lt;/div&gt;&lt;div style=&quot;clear:both;&quot;&gt;&lt;/div&gt;
    </recommendedItem>
    <recommendedItem id="20100101_19_206"
                     title="Treadmill Training Improves Walking in Parkinson&apos;s (CME/CE)"
                     score="-0.004"
                     href="http://www.medpagetoday.com/Neurology/ParkinsonsDisease/tb/18049?impressionId=1265798815900"
                     
      Treadmill training can improve the impaired walking associated with Parkinson&apos;s disease, researchers said.&lt;br&gt;
&lt;br&gt;The technique leads to improvements in gait speed, stride length, and walking distance, but not gait cadence, according to Jan Mehrholz, PhD, of the Klinik Bavaria in Kreischa, Germany, and colleagues.&lt;br&gt;
&lt;br&gt;However, it remains unclear how long such improvements last, the researchers noted in a &lt;em&gt;Cochrane Systematic Review&lt;/em&gt;.&lt;br&gt;
&lt;br&gt;Treadmill training has emerged recently as a &quot;promising investigational therapy&quot; aimed at patients with weakness on one side of the body and impaired gait, Mehrholz and colleagues wrote in their review.&lt;br&gt;
&lt;br&gt;To evaluate what&apos;s known about the subject, the researchers searched the literature and found eight randomized, controlled studies with a total of 203 participants.&lt;/p&gt;
&lt;p&gt;On average, patients were 61, with an average duration of disease in the studies ranging from one to eight years.&lt;/p&gt;
&lt;p&gt;When the studies were analyzed, the researchers found: 


&lt;table style=&quot;color: #151515; line-height: 16px; font: normal 14px Arial;&quot;&gt;
                &lt;tr&gt;&lt;td valign=&quot;top&quot;&gt;&lt;li&gt;&lt;/li&gt;&lt;/td&gt; &lt;td&gt;Seven studies  --  with153 participants all told  --  found that treadmill training improved gait speed. The pooled standardized mean difference was 0.50, which was significant at &lt;em&gt;P&lt;/em&gt;=0.003.&lt;/td&gt;&lt;/tr&gt;
                &lt;tr&gt;&lt;td valign=&quot;top&quot;&gt;&lt;li&gt;&lt;/li&gt;&lt;/td&gt; &lt;td&gt;Five studies, with a total of 95 participants, looked at stride length and found that treadmill training was beneficial. The pooled standardized mean difference was 0.50, which was significant at &lt;em&gt;P&lt;/em&gt;=0.05.&lt;/td&gt;&lt;/tr&gt;
                &lt;tr&gt;&lt;td valign=&quot;top&quot;&gt;&lt;li&gt;&lt;/li&gt;&lt;/td&gt; &lt;td&gt;Two studies, with 41 participants, found that treadmill training improved walking distance. The mean difference was 358 meters, which was significant at &lt;em&gt;P&lt;/em&gt;&amp;lt;0.0001.&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td valign=&quot;top&quot;&gt;&lt;li&gt;&lt;/li&gt;&lt;/td&gt; &lt;td&gt;Finally, four studies (with 78 participants) found no significant mean difference in cadence.&lt;/td&gt;&lt;/tr&gt;
              &lt;/table&gt;

&lt;p&gt;The treadmill training was acceptable to patients, the researchers said, in that it did not increase the risk of patients dropping out of studies. Adverse events were not reported.&lt;/p&gt;
&lt;p&gt;The researchers noted that the study protocols varied markedly.&lt;/p&gt;
&lt;p&gt;The treadmill training lasted from one 30-minute session to eight weeks, although most studies used a four-, six- or eight-week period. Frequency varied from a single session to four times a week, the researchers said.&lt;/p&gt;
&lt;p&gt;The type of treadmill training also varied, with some investigators using body-weight supported treadmill training and others a speed-dependent approach.&lt;/p&gt;
&lt;p&gt;Primary outcomes also differed, Mehrholz and colleagues said.&lt;/p&gt;
&lt;p&gt;Because of those variations, they said, there is &quot;still a need for well-designed large-scale studies&quot; to look at the risk and benefits of treadmill training for Parkinson&apos;s patients.&lt;/p&gt;
&lt;p&gt;Specifically, they said, those studies should address open questions about how long the effect lasts and what should be the frequency and duration of training.&lt;/p&gt;
&lt;div style=&quot;float:left;border-style:solid;border-width:1px;border-color:#8dabbc;font-family:arial;font-size:12px;background-color:#DBE9F2;padding:5px;&quot;&gt;&lt;p&gt;The study was supported by the Klinik Bavaria Kreischa, the Technical University Dresden, SRH Fachhochschule Gera, and the California State University Long Beach.&lt;/p&gt;&lt;p&gt;Mehrholz and another author were co-authors of one included trial but did not participate in its quality assessment and data extraction.&lt;/p&gt;&lt;/div&gt;&lt;div style=&quot;clear:both;&quot;&gt;&lt;/div&gt;
    </recommendedItem>
    <recommendedItem id="20090101_19_2891"
                     title="Pesticides Implicated in Parkinsonism (CME/CE)"
                     score="-0.005"
                     href="http://www.medpagetoday.com/Neurology/ParkinsonsDisease/tb/15948?impressionId=1265798815900"
                     
      &lt;p&gt;The risk of parkinsonism doubled with increased occupational exposure to pesticides, including eight agents associated with experimental parkinsonism, according to data from patients at North American movement disorder centers.&lt;/p&gt;
&lt;p&gt;Any exposure to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) almost tripled the risk of parkinsonism compared with individuals who reported no exposure to the agent, according to a report in the September &lt;em&gt;Archives of Neurology&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;Developed in 1946, 2,4-D was the first successful selective herbicide and is now the most widely used weed killer in the world.&lt;/p&gt;
&lt;p&gt;&quot;Occupational pesticide exposure emerges as the most consistent etiologic association with parkinsonism&quot;, Caroline M. Tanner, MD, PhD, of the Parkinson&apos;s Institute in Sunnyvale, Calif., and colleagues concluded in their report.&lt;/p&gt;
&lt;p&gt;&quot;This convergence of epidemiologic and laboratory data from experimental models of Parkinson&apos;s disease lends credence to a causative role of certain pesticides in the neurodegenerative process,&quot; they added.&lt;/p&gt;
&lt;p&gt;&quot;Other pesticide exposures such as hobby gardening, residential exposure, wearing treated garments, or dietary intake were not assessed. Because these exposures may affect many more subjects, future attention is warranted.&quot;&lt;/p&gt;
&lt;p&gt;While researchers had suspected occupational chemical exposure as an etiologic factor in Parkinson&apos;s disease, previous studies yielded inconsistent findings. Few studies evaluated a possible direct relationship between occupational chemical exposure and Parkinson&apos;s disease, the authors said.&lt;/p&gt;
&lt;p&gt;Some evidence had suggested that toxicant-induced parkinsonism has atypical features, but that issue also had not been systematically investigated.&lt;/p&gt;
&lt;p&gt;To address limitations of current data, Tanner and colleagues enrolled patients at eight North American movement disorder centers in a case-control study of parkinsonism risk associated with occupations and exposure to toxicants.&lt;/p&gt;
&lt;p&gt;The investigation focused on five occupations previously suggested as posing an increased risk of parkinsonism: agriculture, education, healthcare, welding, and mining. Examination of toxicant exposures included solvents and pesticides putatively associated with parkinsonism.&lt;/p&gt;
&lt;p&gt;To reduce the potential for excluding toxicant-induced cases, investigators enrolled patients with typical and atypical features. Occupation was determined in accordance with the 2000 Standard Occupational Classification manual. Toxicant exposure was assessed from detailed information about patients&apos; job tasks.&lt;/p&gt;
&lt;p&gt;The study included 519 patients with parkinsonism and 511 age- and sex-matched controls. The authors found no association between parkinsonism and work in agriculture, education, healthcare, or welding.&lt;/p&gt;
&lt;p&gt;Any history of work in business and finance, legal occupations, construction and extraction, or transportation and material moving was associated with an increased risk of postural instability and the gait-difficulty subtype of parkinsonism.&lt;/p&gt;
&lt;p&gt;The adjusted odds ratio for parkinsonism increased with pesticide use (OR 1.90, 95% CI 1.12 to 3.21), use of any of eight agents linked to experimental parkinsonism (OR 2.20, 95% CI 1.02 to 4.75), and exposure to 2,4-D (OR 2.59, 95% CI 1.03 to 6.48).&lt;/p&gt;
&lt;p&gt;Specific occupation, job tasks, or task-related exposures were not associated with diagnosis of parkinsonism at a younger age.&lt;/p&gt;
&lt;p&gt;Limitations of the study included use of a referral population, exclusion of patients with dementia, and a largely Caucasian group, all of which may limit generalization of the findings to other groups.&lt;/p&gt;
&lt;p&gt;Other limitations include the absence of pesticide exposure measurements, as opposed to patient recall, inclusion of multiple association data, and inability to determine causality from case-control studies.&lt;/p&gt;
&lt;div style=&quot;float:left;border-style:solid;border-width:1px;border-color:#8dabbc;font-family:arial;font-size:12px;background-color:#DBE9F2;padding:5px;&quot;&gt;&lt;p&gt;Co-author Robert A. Hauser disclosed relationships involving expert testimony related to parkinsonism.&lt;/p&gt;&lt;/div&gt;&lt;div style=&quot;clear:both;&quot;&gt;&lt;/div&gt;
    </recommendedItem>
    <recommendedItem id="20090101_5_402"
                     title="Parkinson&apos;s Association with Pesticide Exposure Gains Strength"
                     score="-0.005"
                     href="