Epidemiologic and Economic Burden of Achalasia in the United States

BACKGROUND & AIMS

Achalasia is a debilitating chronic condition of the esophagus. Currently there are no national estimates on the epidemiologic and economic burden of disease. We sought to estimate trends in incidence and prevalence of achalasia by age-sex strata, and to estimate the total direct medical costs attributed to achalasia in the United States.

METHODS

We conducted a cohort study using two administrative claims databases: IBM MarketScan Commercial Claims and Encounters database (2001-2018; age <65) and a 20% sample of nationwide Medicare enrollment and claims (2007-2015; age ≥65). Point prevalence was calculated on the first day of each calendar year; the incidence rate captured new cases developed in the ensuing year. Utilization rates of healthcare services and procedures were reported. Mean costs per patient were calculated and standardized to the corresponding U.S. Census Bureau population data to derive achalasia-specific total direct medical costs.

RESULTS

The crude prevalence of achalasia per 100,000 persons was 18.0 (95% CI, 17.4, 18.7) in MarketScan and 162.1 (95% CI, 157.6, 166.6) in Medicare. The crude incidence rate per 100,000 person-years was 10.5 (95% CI, 9.9, 11.1) in MarketScan and 26.0 (95% CI, 24.9, 27.2) in Medicare. Incidence and prevalence increased substantially over time in the Medicare cohort, and increased with more advanced age in both cohorts. Utilization of achalasia-specific healthcare was high; national estimates of total direct medical costs exceeded $408 million in 2018.

CONCLUSIONS

Achalasia has a higher epidemiologic and economic burden in the US than previously suggested, with diagnosis particularly increasing in older patients.

Growing colorectal tumors: minimizing microbial and stromal competition and assessing in vitro selection pressures

Development of primary colorectal cancer cell lines ishampered by contamination from regional microbes, overgrowthof stromal cells, and purported genetic drift from selectionpressures in vitro. We initiated 32 primaryadenocarcinomas, 3 recurrences and 6 distant metastases incell culture. Twelve cell lines from eleven tumors weregenerated (26.8%) overall. Nine of 32 primary tumorsyielded 10 cell lines, 5 were lost to contamination, 13 wereoverwhelmed by stromal cells, and 5 demonstrated no growth.Addition of isobutyl methyl xanthine (IBMX) to culturelimited fibroblastoid growth. There was no associationbetween tumor location (p = 0.535, mid-P), degree ofdifferentiation (p = 0.850, mid-P) or clinicopathologic stage(p = 0.400, mid-P), and the ability of cells to becomeestablished in culture. The majority of cell lines hadsimilar nuclear DNA content and expression of cell-surfaceantigens compared with their parent tumors. Microbialcontamination and stromal cell overgrowth present thegreatest obstacle to capturing a representative bank ofcolon tumors in vitro.

All “chick-a-dee” calls are not created equally

The 'chick-a-dee' call, common to all members of the genus Poecile, is used by both sexes throughout the year to putatively co-ordinate flock movements and register alarm. In some regions, two or more chickadee species occupy overlapping territories, and therefore it is essential that these sympatric species learn to discriminate between the acoustically similar calls of the species. Previous work from our laboratory has shown that black-capped (P. atricapillus) and mountain chickadees (P. gambeli) discriminate between the species' calls and treat each species' calls as belonging to separate open-ended categories. In the current set of experiments we use an operant conditioning paradigm to gain an understanding of (1) how the birds perform this discrimination and (2) whether birds with different levels of experience with heterospecific calls perform this task differently. We use natural recordings of chick-a-dee calls and perform several manipulations to test the importance of the introductory 'chick-a' portion and the terminal 'dee' portion for discriminating among the calls of the two species. Evidence suggests that birds mainly use the terminal 'dee' portion, as all groups of birds responded similarly to these probe stimuli and control chick-a-dee calls. We propose that the terminal 'dee' portion, consisting of lower frequency notes, is more likely to be resistant to degradation, and therefore a more reliable species-specific marker.

Proton pump inhibitors reduce gallbladder function

BACKGROUND

In the authors' previous study of gallbladder function before and after fundoplication, 58% of the patients demonstrated preoperative gallbladder motor dysfunction, and 86% of those retested after operation and cessation of proton pump inhibitors (PPIs) normalized. Because no study has directly assessed the impact of antisecretory agents on gallbladder function, this study measured gallbladder ejection fraction (GBEF) in healthy volunteers before and after initiation of PPIs.

METHODS

A total of 19 subjects completed the study, which included baseline determination of GBEF by cholecystokinin-stimulated hepatobiliary acid scan, 30 days of antisecretory therapy with omeprazole (40 mg daily), and repeat GBEF on day 30. Subjects were surveyed regarding compliance and symptoms.

RESULTS

For 15 of 19 subjects, PPI therapy was associated with reduced gallbladder motility. Evolution of symptoms consistent with a biliary etiology was reported by 26.7% of these subjects.

CONCLUSIONS

Short-term PPI therapy reduces gallbladder motility in healthy volunteers. Chronic PPI therapy may pose a risk for long-term gallbladder dysfunction and biliary complications.

Response of atypical symptoms of gastro-oesophageal reflux to antireflux surgery

BACKGROUND

Atypical manifestations of gastro-oesophageal reflux (GOR) include asthma, chest pain, cough and hoarseness. The effectiveness of antireflux surgery for these symptoms is uncertain. The present study compared symptomatic response rates for typical and atypical GOR symptoms after fundoplication.

METHODS

Between October 1991 and January 1998, 324 patients underwent laparoscopic fundoplication at Emory University Hospital and returned postoperative questionnaires. Severity of typical (heartburn) and atypical (asthma, chest pain, cough and hoarseness) GOR symptoms was reported by patients on a 0-4 scale before surgery, and at 6 and 52 weeks after operation. Patients were stratified based on preoperative symptoms into three groups: group 1 (severe heartburn/minimal atypical symptoms), group 2 (severe heartburn/severe atypical symptoms) and group 3 (minimal heartburn/severe atypical symptoms).

RESULTS

In group 1 (n = 173) heartburn improved in 99 per cent and resolved in 87 per cent. In group 2 (n = 95) heartburn improved in 95 per cent and resolved in 76 per cent, and atypical symptoms improved in 94 per cent and resolved in 42 per cent. In group 3 (n = 56) atypical symptoms improved in 93 per cent and resolved in 48 per cent. Although all symptoms were improved by fundoplication, resolution was more likely for heartburn than for atypical symptoms.

CONCLUSION

Atypical symptoms of GOR are improved by fundoplication, but symptom resolution occurs in fewer than 50 per cent of patients.

Resection and advancement of esophageal mucosa. A potential therapy for Barrett's esophagus

BACKGROUND

Barrett's esophagus affects 5-10% of patients with gastroesophageal reflux disease (GERD) and is associated with a 40-fold increased risk of malignant transformation. Ablative therapies may lead to esophageal perforation or stricture formation if applied too liberally and residual glandular tissue and persistent cancer risk if utilized too sparingly.

METHODS

Ten pigs underwent gastrotomy. Mucosa below the gastroesophageal (GE) junction was elevated by saline injections, circumferentially incised, and secured to an orogastric tube. By traction, the distal esophageal mucosa was inverted 10 cm proximally, then returned to the gastric lumen. In group A (n = 4), the mucosa (5 cm) was resected and the remnant was allowed to retract. In group B (n = 4), the mucosa was simply sutured back into its native position. In group C (n = 2), the mucosa (5 cm) was resected and the proximal segment was advanced and sutured to the gastric mucosa. At 6 weeks, or sooner if stricture developed, the animals were killed. Stricture formation was determined by ex vivo barium esophagram and gross assessment. The extent of fibrosis and epithelial healing were established histologically.

RESULTS

Group A (mucosa resected) developed weight loss and anorexia within 4 weeks. Pathology revealed dense fibrotic stricture without reepithelialization. Group B (mucosa elevated/replaced) gained weight after the operation. Histology demonstrated mucosal healing without significant stricture or fibrosis. Group C (mucosa resected/advanced) also thrived postoperatively. Histology confirmed mucosal healing without evidence of retraction or dense stricture.

CONCLUSIONS

Exposure of submucosal tissues causes esophageal stricture. Mucosal coverage minimizes submucosal fibrosis after injury. Mucosal resection and advancement allows healing without stricture and may have therapeutic potential for patients with Barrett's esophagus.

Assessing laparoscopic manipulative skills

BACKGROUND

The rapid emergence of laparoscopic surgery over the past decade has highlighted the need for teaching and assessing laparoscopic manipulative skills. Most analyses consist of a measurement of the time to complete a specified task and a subjective assessment by an observer. Objective assessments of accuracy in the performance of manipulative skills have been lacking. To quantify both speed and accuracy during laparoscopic skill performance, we have developed a skills assessment device (SAD) using a laparoscopic simulator platform and computer-based skills assessment software that precisely measures an instrument's movement during performance of timed laparoscopic manipulations.

STUDY DESIGN

The SAD device measures the time necessary for an operator to complete a task, and the movements of the working end of laparoscopic instruments in three dimensions. Ten nonsurgeons performed 10 repetitions of a standardized laparoscopic manipulation. Data were captured in real time for both hands on a personal computer. Accuracy was determined by calculating the sum of all distances traveled. Duration was measured in seconds. Results are group means.

RESULTS

The time necessary to perform defined laparoscopic manipulative skills improved dramatically during the first 3 repetitions and then stabilized. However, accuracy of manipulations continued to improve over all 10 repetitions.

CONCLUSIONS

When untrained subjects are learning a laparoscopic manipulative task, measurement of time alone fails to account for the more protracted learning curve for accuracy. Therefore, devices and training programs that fail to consider objective assessments of accuracy may overestimate laparoscopic proficiency.

Nissen fundoplication improves gastric motility in patients with delayed gastric emptying

BACKGROUND

Fundoplication hastens gastric emptying in pediatric patients with gastroesophageal reflux disease (GERD). However, among adult GERD patients with impaired gastric emptying, the degree of improvement offered by fundoplication and the value of pyloroplasty are less well defined. Therefore, we compared outcomes in GERD patients with delayed gastric emptying after fundoplication alone or fundoplication with pyloroplasty.

METHODS

Of 616 consecutive GERD patients who submitted to primary fundoplication (601 laparoscopic) between October 1991 and October 1997, 82 underwent preoperative solid-phase nuclear gastric emptying analysis. Of these, 25 had delayed gastric emptying (half-time >100 min). Of 12 patients with emptying half-times between 100 and 150 min, one underwent pyloroplasty at the time of Nissen fundoplication. Of 13 patients with emptying half-times >150 min, 11 had pyloroplasty at the time of Nissen fundoplication. Patients were asked to use a 0 ("none") to 4 ("incapacitating") scale to describe the severity of their symptoms of heartburn, regurgitation, dysphagia, bloating and diarrhea preoperatively and at 6 weeks and 1 year postoperatively. Eight patients consented to a postoperative analysis of gastric emptying.

RESULTS

One year after fundoplication, patients with delayed gastric emptying and controls reported a similar improvement in heartburn, regurgitation, and dysphagia, with no increase in undesirable side effects such as bloating and diarrhea. Among the patients with delayed gastric emptying who consented to undergo a repeat gastric emptying study after their operation, fundoplication alone provided a 38% improvement (p < 0.05) in gastric emptying, whereas fundoplication with pyloroplasty resulted in a 70% improvement in gastric emptying (p < 0.05).

CONCLUSION

Fundoplication improves gastric emptying. The addition of pyloroplasty results in even greater improvement and may have particular value for patients with severe gastric hypomotility.

Complete fundoplication is not associated with increased dysphagia in patients with abnormal esophageal motility

Abnormal esophageal motility is a relative contraindication to complete (360-degree) fundoplication because of a purported risk of postoperative dysphagia. Partial fundoplication, however, may be associated with increased postoperative esophageal acid exposure. Our aim was to determine if complete fundoplication is associated with increased postoperative dysphagia in patients with abnormal esophageal motor function. Medical records of 140 patients (79 females; mean age 48 +/- 1.1 years) who underwent fundoplication for gastroesophageal reflux disease (GERD) were reviewed retrospectively to document demographic data, symptoms, and diagnostic test results. Of the 126 patients who underwent complete fundoplication, 25 met manometric criteria for abnormal esophageal motility (#30 mm Hg mean distal esophageal body pressure or #80% peristalsis), 68 had normal esophageal function, and 33 had incomplete manometric data and were therefore excluded from analysis. Of the 11 patients who underwent partial fundoplication, eight met criteria for abnormal esophageal motility, two had normal esophageal function, and one had incomplete data and was therefore excluded. After a median follow-up of 2 years (range 0.5 to 5 years), patients were asked to report heartburn, difficulty swallowing, and overall satisfaction using a standardized scoring scale. Complete responses were obtained in 72%. Sixty-five patients who underwent complete fundoplication and had manometric data available responded (46 normal manometry; 19 abnormal manometry). Outcomes were compared using the Mann-Whitney U test. After complete fundoplication, similar postoperative heartburn, swallowing, and overall satisfaction were reported by patients with normal and abnormal esophageal motility. Likewise, similar outcomes were reported after partial fundoplication. This retrospective study found equally low dysphagia rates regardless of baseline esophageal motility; therefore a randomized trial comparing complete versus partial fundoplication in patients with abnormal esophageal motility is warranted.

Choice of insufflating gas influences on wound metastasis

BACKGROUND

Laparoscopic cancer surgery is limited by concerns about port-site metastasis. No study has definitively addressed the behavior and growth of tumor cells after the use of specific laparoscopic gases.

METHODS

In athymic rats, 10,000 colon cancer cells were injected intraperitoneally. The rats received either no pneumoperitoneum (pneumo) or pneumo (8 mmHg, 10 min) with carbon dioxide (CO(2)), nitrous oxide (N(2)O), or air. Two full-thickness incisions were made and closed in the upper abdomen of each animal. After 4 weeks, implants were identified grossly at necropsy, and invasiveness was scored according to penetration through the layers of the abdominal wall.

RESULTS

Rats receiving pneumo had more frequent implants (p < 0.01) with deeper penetration (p < 0.001) than rats not receiving pneumo. Implants were more common after air pneumo than after CO(2) (p < 0.05) or N(2)O (p = 0.07) pneumo, and were less penetrating after CO(2) pneumo than after air (p < 0.001) or N(2)O (p < 0.05) pneumo.

CONCLUSIONS

Carbon dioxide gas may limit the viability and invasiveness of free intraperitoneal tumor cells, as compared with air or N(2)O.

Heartburn is more likely to recur after Toupet fundoplication than Nissen fundoplication

Toupet (270 degrees) fundoplication is commonly recommended for patients with gastroesophageal reflux (GER) and esophageal dysmotility. However, Toupet fundoplication may be less effective at protecting against reflux than Nissen (360 degrees) fundoplication. We therefore compared the effectiveness and durability of both types of fundoplication as a function of preoperative esophageal motility. From January 1992 through January 1998, 669 patients with GER underwent laparoscopic fundoplication (78 Toupet, 591 Nissen). Patients scored heartburn, regurgitation, and dysphagia preoperatively, and at 6 weeks and 1 year postoperatively, using a 0 ("none") to 3 ("severe") scale. We compared symptom scores (Wilcoxon rank sum test) and redo fundoplication rates (Fisher exact test) in Toupet and Nissen patients. We also performed subgroup analyses on 81 patients with impaired esophageal motility (mean peristaltic amplitude, <30 mm Hg or peristalsis <70% of wet swallows) and 588 patients with normal esophageal motility. Toupet and Nissen patients reported similar preoperative heartburn, regurgitation, and dysphagia. At 6 weeks after operation, heartburn and regurgitation were similarly improved in both groups, but dysphagia was more prevalent among Nissen patients. After 1 year, heartburn and regurgitation were re-emerging in Toupet patients, and dysphagia was again similar between groups. Patients with impaired motility who have Nissen fundoplication are no more likely to suffer persistent dysphagia than their counterparts who have Toupet fundoplication. In addition, patients with normal motility are more likely to develop symptom recurrence after Toupet fundoplication than Nissen fundoplication, with no distinction in dysphagia rates. We conclude that since Toupet patients suffer more heartburn recurrence than Nissen patients, with similar dysphagia, selective use of Toupet fundoplication requires further study.

Endogastric surgery

Endogastric surgery is a branch of minimally invasive surgery that combines flexible endoscopy and laparoscopy. By placing trocars directly into the stomach, quite a number of procedures may be performed. Leiomyomas and other benign gastric tumors are readily removed, and in Asia early gastric cancers are removed with these techniques. Large pancreatic pseudocysts abutting the posterior wall of the stomach may be drained through the stomach using an endogastric approach. Lastly, intragastric bleeding in areas not reachable with a conventional endoscope may be approached with an endogastric approach. Although the indications for these procedures are-in general-rare, they are not difficult to perform, and outcomes have been superb.

Fundoplication provides effective and durable symptom relief in patients with Barrett's esophagus

BACKGROUND

Columnar-lined esophagus with intestinal metaplasia (IM), also called Barrett's esophagus, is a manifestation of severe gastroesophageal reflux (GER) and may predict poor symptom relief and high failure rate after fundoplication. We compared symptom scores and reoperation rates in GER patients with and without Barrett's esophagus.

METHODS

Between July 1992 and July 1997, 646 patients underwent fundoplication (626 laparoscopic). Of 150 endoscopic biopsies of suspected columnar-lined esophagus, 80 confirmed IM, 50 identified cardiac or fundic epithelium, and 20 revealed only esophagitis. Typical GER symptoms were scored by patients preoperatively and postoperatively (0 to 4 scale). We compared symptom response (Wilcoxon rank sum test) and failure rates (t test) in patients with IM and GER controls without IM. Preoperative data were available for 74 IM patients and 496 controls. One-year follow-up was available in 45 IM patients and 301 controls. Intermediate follow-up (2 to 5 years) was available in 20 IM patients and 99 controls.

RESULTS

Preoperatively and postoperatively, patients with IM reported heartburn, regurgitation, and dysphagia scores similar to controls. Procedure failure, requiring redo fundoplication, appeared more likely in IM patients than controls (6.3% versus 2.5%), but this difference did not reach statistical significance (P = 0.061).

CONCLUSION

Fundoplication provides equivalent symptom relief for patients with and without IM.

Fundoplications resist reflux independent of in vivo anatomic relationships

BACKGROUND

Antireflux operations restore lower esophageal sphincter (LES) function and hiatal anatomy; however, the relative contributions are unclear.

METHODS

We measured the competency of fundoplications, exclusive of in vivo variables, in gastroesophageal explants from 8 cadavers. Using a multichannel manometer, esophageal, LES, and intragastric pressures were recorded during transpyloric distension. Data were compared at baseline, and after Nissen (360 degrees) and Toupet (270 degrees) fundoplications.

RESULTS

Before fundoplication, stomachs refluxed immediately upon distension. Nissen fundoplications never refluxed before gastric rupture (46.8 +/- 15.0 mm Hg). LES pressure averaged 2.0 +/- 0.5 times intragastric pressure during distension. Toupet fundoplications refluxed at intragastric pressure <2 mm Hg, then became competent until gastric rupture (49.9 +/- 15.0 mm Hg). LES pressure averaged 2.4 +/- 1.0 times intragastric pressure during distension.

CONCLUSIONS

Nissen and Toupet fundoplications increase LES pressure linearly at 2 to 2.5 times intragastric pressure, independent of in vivo variables. Toupet fundoplication lacks the competency of Nissen fundoplication at low intragastric pressures.

Laparoscopic fundoplication for dysphagia and peptic esophageal stricture

Peptic esophageal stricture with dysphagia is a late manifestation of severe gastroesophageal reflux disease (GERD). Although laparoscopic fundoplication is an effective antireflux operation, its efficacy for persons with peptic esophageal stricture and dysphagia has not been well defined. The aim of this study was to evaluate outcomes after fundoplication in this subgroup of GERD patients. Forty GERD patients with moderate, severe, or incapacitating dysphagia and peptic esophageal stricture were compared to a control group of 121 GERD patients without significant dysphagia or stricture. Reflux symptom severity was scored by each patient preoperatively and at most recent follow-up postoperatively (mean 1.5 years) using a scale ranging from 0 to 4 (0 = symptoms absent; 4 = symptoms incapacitating). Symptom scores were compared by the Wilcoxon rank-sum test. Postoperative redilation and fundoplication failure rates were also determined. At a mean follow-up of 1.5 years after fundoplication, the median dysphagia score had improved from 3 to 0 (P <0.001) in stricture patients and remained low (score 0) in the control group. The median heartburn score also improved from 3 to 0 (P <0.001) in stricture patients, with an identical response in the control group (P <0.001). Among dysphagia/stricture patients, 35 (87.5%) reported overall satisfaction and have not required secondary medical treatment or esophageal dilation. Four patients (10%) have required endoscopic redilation for residual dysphagia and one (2.5%) had reoperation for fundoplication herniation shortly after operation. Laparoscopic fundoplication is an effective therapy for patients with dysphagia and peptic esophageal stricture.

Laparoscopic management of gastroesophageal reflux disease

This monograph provides a review of the contemporary surgical management of gastroesophageal reflux disease (GERD), drawing primarily on the experience at Emory University Hospital. We emphasize the importance of precise anatomic and physiologic preoperative evaluation to confirm the diagnosis of GERD, and stress technical aspects of laparoscopic fundoplication that have improved outcomes.

Moose-motor vehicle collisions. An increasing hazard in northern New England

OBJECTIVE

To analyze the epidemiology and epizootiology of moose-motor vehicle collisions (MMVC) and outcomes in severely injured patients to identify variables that might be modified to reduce the impact of this mutually deleterious interspecies interaction.

DESIGN

Wildlife and Traffic Safety databases permitted retrospective, population-based assessment of MMVC epidemiology. A case series compiled from hospital trauma registries characterized morbidity and mortality from MMVC.

SETTING

New Hampshire and Maine area.

PATIENTS

All victims of MMVC (1980 through 1991) were included in population-based analyses. Twenty-three patients hospitalized at three rural trauma centers (January 1990 through June 1994) were included in the case series.

MAIN OUTCOME MEASURES

Location, time of day and seasonal occurrence of MMVC were determined. Injury patterns and Injury Severity Scores were analyzed in 23 representative patients. Maine's 1991 traffic and medical data were linked, and factors predictive of injury from MMVC were identified using multivariate logistics.

RESULTS

Most MMVC occur from April through October after dark. Of 23 subjects, 70% sustained head and/or face injuries and 26%, cervical spine injuries. Mortality was 9%. Mean Injury Severity Score was 15.7 (SD=9.0). Safety belt use, rear seat location, and light truck occupancy were associated with reduced injury (p<.05).

CONCLUSIONS

Moose-motor vehicle collisions are increasing in rural regions. Prevention programs should emphasize defensive driving and seat belt use, especially during high-risk periods. Injury patterns in MMVC suggest a need for automobile design modifications that better protect the passenger compartment form direct impact.

Follow-up study of early-life protective and risk factors in Parkinson's disease

Previous studies suggest that Parkinson's disease (PD) is negatively associated with early-life intake of vitamin E-rich foods and positively associated with rural experience. Using a new survey design, we attempted to confirm and extend these results. We gave a telephone questionnaire to 106 patients with PD and to their spouses as controls. It assessed premarital consumption of 31 foods of various vitamin E content, vitamin supplements, and exposure to rural living. Respondents rated food consumption with respect to what they perceived as the average for their sex and age at that time. We found female patients with PD less likely than spouses to have eaten "peanuts and peanut butter" (p less than .05), which are high in vitamin E. "Salad with dressing," also high in vitamin E, gave a similar result (p less than .05) for a male-predominant patient group. Separate comparison of male controls with female controls ruled out sex-related preferences as the explanation of our findings. Patients had more extensive rural experience and were more likely to have frequently sprayed pesticides (p less than .05) than had controls. Our results justify further investigations into early-life vitamin E intake, pesticides, and neurotoxins associated with rural life.

Case-control study of early life dietary factors in Parkinson's disease

Studies of the amyotrophic lateral sclerosis parkinsonism dementia complex of Guam direct suspicion to a heat-labile component of vegetables found in greatest concentration in seeds. We therefore surveyed patients with Parkinson's disease (PD) regarding early adult consumption of fruits and vegetables usually eaten raw, with seeds that are swallowed or scraped with the teeth. We administered a pretested questionnaire by telephone to 81 nondemented patients with PD and to a same-sex married sibling without PD. The patients and their siblings were asked whether they or their spouse (as an internal standard) had been more likely to eat each of 17 food items between marrying and age 40 years. No item was associated with the presence of PD. Unexpectedly associated with the absence of PD were preference for nuts (odds ratio, 0.39), salad oil or dressing (pressed from seeds) (odds ratio, 0.30), and plums (odds ratio, 0.24). These three items have higher vitamin E content than the other 14 items in our questionnaire. Our data are consistent with the hypothesis that vitamin E, as an antioxidant, may have prophylactic value against PD.