Nigerian Pharmacist

*Melatonin May Cut Risk for Age-Related Eye Disease*
Edited by Adam Marcus

June 06, 2024



*TOPLINE:*
Melatonin supplementation is linked to a reduced risk for developing age-related macular degeneration (AMD) and slowing its progression, suggesting potential as a preventive therapy.

*METHODOLOGY* :
Researchers analyzed data from the TriNetX database, covering electronic medical records across the United States from December 2023 to March 2024.
The retrospective study included patients aged ≥ 50 years, divided into groups based on their history of AMD and melatonin medication codes between November 2008 and November 2023.
Propensity score matching was used to compare melatonin users and nonusers for the risk for developing any form of AMD or the progression to exudative AMD from the nonexudative form of the condition.
TAKEAWAY:
Use of melatonin was associated with a 58% reduction in the risk for developing AMD, according to the researchers.
In people with nonexudative AMD, use of the supplement was linked to a 56% lower risk for progression to exudative AMD.
The findings were consistent across age groups, suggesting melatonin's benefits may extend to older populations at higher risk for AMD, the researchers reported.
IN PRACTICE:
"In this cohort study of 121,523 patients with no history of AMD aged ≥ 50 years, taking melatonin was associated with a decreased risk of developing AMD," the authors of the study wrote. "Likewise, among 66,253 patients with preexisting nonexudative AMD, melatonin supplementation was negatively associated with the rate of progression to exudative AMD."

Studies in animals and humans have shown melatonin may be a potent antioxidant and anti-inflammatory agent and have both antiangiogenic and mitochondrial-preserving properties, the authors noted. The new findings "provide a rationale for expanding clinical research on the potential therapeutic efficacy of melatonin in preventing AMD development or its progression," they added.

SOURCE:
The study was led by Hejin Jeong, Case Western Reserve University School of Medicine, Cleveland, and was published online on June 6, 2024, in JAMA Ophthalmology.

LIMITATIONS:
The study's reliance on diagnostic codes may have limited the accuracy of identifying AMD progression. Variations in coding practices and the reporting of over-the-counter medications like melatonin could have influenced the results. The study did not control for all modifiable risk factors for AMD, which may have introduced healthy user bias.

PPI Use in Type 2 Diabetes Links With Cardiovascular Events

Mitchel L. Zoler, PhD

January 10, 2023

Among people with type 2 diabetes who self-reported regularly using a proton pump inhibitor (PPI), the incidence of cardiovascular disease (CVD) events as well as all-cause death was significantly increased in a study of more than 19,000 people with type 2 diabetes in a prospective UK database.

During median follow-up of about 11 years, regular use of a PPI by people with type 2 diabetes was significantly linked with a 27% relative increase in the incidence of coronary artery disease compared with nonuse of a PPI, after full adjustment for potential confounding variables.

The results also show PPI use was significantly linked after full adjustment with a 34% relative increase in myocardial infarction, a 35% relative increase in heart failure, and a 30% relative increase in all-cause death, say a team of Chinese researchers in a recent report in the Journal of Clinical Endocrinology and Metabolism.

PPIs are a medication class widely used in both over-the-counter and prescription formulations to reduce acid production in the stomach and to treat gastroesophageal reflux disease and other acid-related disorders. The PPI class includes such widely used agents as esomeprazole (Nexium), lansoprazole (Prevacid), and omeprazole (Prilosec).

The analyses in this report, which used data collected in the UK Biobank, are "rigorous," and the findings of "a modest elevation of CVD risk are consistent with a growing number of observational studies in populations with and without diabetes," commented Mary R. Rooney, PhD, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore, who focuses on diabetes and cardiovascular diseases.

Prior Observational Reports

For example, a report from a prospective, observational study of more than 4300 US residents published in 2021 that Rooney co-authored documented that cumulative PPI exposure for more than 5 years was significantly linked with a twofold increase in the rate of CVD events compared with people who did not use a PPI. (This analysis did not examine a possible effect of diabetes status.)

And in a separate prospective, observational study of more than 1000 Australians with type 2 diabetes, initiation of PPI treatment was significantly linked with a 3.6-fold increased incidence of CVD events compared with PPI nonuse.

However, Rooney cautions that the role of PPI use in raising CVD events "is still an unresolved question. It is too soon to tell if PPI use in people with diabetes should trigger additional caution." Findings are needed from prospective, randomized trials to determine more definitively whether PPIs play a causal role in the incidence of CVD events, she said in an interview.

US practice often results in unwarranted prolongation of PPI treatment, say the authors of an editorial that accompanied the 2021 report by Rooney and her co-authors.

Long-term PPI Use Threatens Harm

"The practice of initiating stress ulcer prophylaxis [by administering a PPI] in critical care is common," write the authors of the editorial. "Although it is data driven and well intentioned, the possibility of causing harm ― if it is continued on a long-term basis after resolution of the acute illness ― is palpable," warn Nitin Malik, MD, and William S. Weintraub, MD, in their editorial.

The new analyses using UK Biobank data included 19,229 adults with type 2 diabetes and no preexisting coronary artery disease, myocardial infarction, heart failure, or stroke. The cohort included 15,954 people (83%) who did not report using a PPI and 3275 who currently used PPIs regularly. Study limitations include self-report as the only verification of PPI use and lack of information on type of PPI, dose size, or use duration.

The findings remained consistent in several sensitivity analyses, including a propensity-score matched analysis and after further adjustment for use of histamine type-2 receptor antagonists, a drug class with indications similar to those for PPIs.

The authors of the report speculate that mechanisms that might link PPI use and increased CVD and mortality risk could include changes to the gut microbiota and possible interactions between PPIs and antiplatelet agents.

Kiwifruit Found Effective for Constipation

Laird Harrison

Kiwifruit can increase the frequency of bowel movements for people with constipation, according to researchers in New Zealand.

"In addition to improved measures of constipation status, there was a significant improvement in stool consistency, reduction in constipation, indigestion/reflux, and abdominal pain resulting in an improved overall level of GI comfort," write Richard Gearry, MD, PhD, of the University of Otago, New Zealand, and colleagues.

Gearry and colleagues describe their international multicenter controlled trial of kiwifruit as a constipation treatment in The American Journal of Gastroenterology.

Although constipation is common, previous researchers have reported a high rate of dissatisfaction with pharmaceutical treatments.

Fiber found in kiwifruit cell walls swells and holds water, which can soften stools and increase stool frequency. Other components of kiwifruit, such as raphides, may alter mucin production, leading to improved laxation.

Several previous studies have suggested that regular consumption of fresh, green kiwifruit may be effective as a treatment for constipation. However, these studies have typically been small with nonstandardized endpoints, Gearry and colleagues note. In their article, they did not comment on studies of other fresh fruits or vegetables as constipation treatments.

The researchers set out to test the benefits of the fruit in a more rigorous trial. They recruited adults in New Zealand, Italy, and Japan who had either functional constipation or constipation-predominant irritable bowel syndrome (IBS-C), as well as healthy people as controls. The primary difference between functional constipation and IBS-C is that people with IBS-C experience abdominal pain along with constipation, they write.

Between June 12, 2014, and June 17, 2017, 184 participants were enrolled. Participants included 136 women and 48 men, a proportion consistent with the gender prevalence of constipation. The mean age was 30.5 years in Japan, 36.9 years in Italy, and 44.8 years in New Zealand, and the mean body mass index was 20.6 in Japan, 23.0 in Italy, and 25.4 in New Zealand.

For 2 weeks following recruitment, the participants became accustomed to recording their bowel movements with respect to frequency, completeness, spontaneity, stool form, laxative use, and degree of straining.

Participants were then randomly assigned to consume either two ripe green kiwifruit (Actinidia chinensis var. deliciosa "Hayward") without the skins, or 7.5 g of psyllium per day for 4 weeks. Psyllium is considered a first-line treatment for both the constipation conditions with which participants were diagnosed. The fiber content of psyllium is similar to that of kiwifruit.

After 4 weeks, treatments were stopped for 4 weeks as a washout period, after which patients were switched to the other treatment for another 4 weeks.

The researchers provided them with two bisacodyl (5-g suppositories) as a pharmacologic rescue therapy.

Overall, 169 participants completed the study, and compliance with diary completion was over 80%.

At the end of the 4-week treatment periods, the people with functional constipation who ate kiwifruit demonstrated an average increase of 1.53 bowel movements per week, a statistically significant increase (P < .0001). Those with IBS-C demonstrated an increase of 1.73 (P = .0001). Both groups reported significantly improved gastrointestinal comfort on the gastrointestinal symptom rating scale.

The frequency of bowel movements in the healthy participants did not increase.

Among those participants who took psyllium, only those with IBS-C experienced a statistically significant increase in the frequency of their bowel movements or a decrease in their gastrointestinal symptoms. Their bowel movements increased by an average of 1.87 per week (P = .0051).

The participants who ate kiwifruit reported softening of stool consistency, reduction in straining, and improvement in quality of life compared to baseline, and these improvements in straining and stool consistency were better than was reported by those who took psyllium.

"Taken in conjunction with previous clinical trials of green kiwifruit and the emerging physiological data from functional studies, consumption of two green kiwifruit can be safely recommended as an effective treatment for constipation in those with functional gastrointestinal disorders that will also provide improvements in symptoms of GI comfort," the researchers conclude.

Vitamins or Cocoa: Which Preserves Cognition?

Kelli Whitlock Burton
September 14, 2022

Unexpected results from a phase 3 trial exploring the effect of multivitamins and cognition have now been published.

Findings from a phase 3 study show daily multivitamin use, but not cocoa, is linked to a significantly slower rate of age-related cognitive decline.

Originally presented last November at the 14th Clinical Trials on Alzheimer's Disease (CTAD) conference and reported by Medscape Medical News at that time, this is the first large-scale, long-term randomized controlled trial to examine the effects of cocoa extract and multivitamins on global cognition. The trial's primary focus was on cocoa extract, which earlier studies suggest may preserve cognitive function. Analyzing the effect of multivitamins was a secondary outcome.

Showing vitamins, but not cocoa, was beneficial is the exact opposite of what researchers expected. Still, the results offer an interesting new direction for future study, lead investigator Laura D. Baker, PhD, professor of gerontology and geriatric medicine at Wake Forest School of Medicine, Winston-Salem, North Carolina, told Medscape Medical News.

"This study made us take notice of a pathway for possible cognitive protection," Baker said. "Without this study, we would never have looked down that road."

Unexpected Effect
The COSMOS-Mind study is a sub-study to a larger parent trial called COSMOS. It investigated the effects of cocoa extract and a standard multivitamin-mineral (MVM) on cardiovascular and cancer outcomes in more than 21,000 older participants.

In COSMOS-Mind, researchers tested whether daily intake of cocoa extract vs placebo and a multivitamin-mineral vs placebo improved cognition in older adults.

More than 2200 participants aged 65 and older were enrolled and followed for 3 years. They completed tests over the telephone at baseline and annually to evaluate memory and other cognitive abilities.

Results showed cocoa extract had no effect on global cognition compared with placebo (mean z-score, 0.03; P = .28). Daily multivitamin use, however, did show significant benefits on global cognition vs placebo (mean z, 0.07, P = .007).

The beneficial effect was most pronounced in participants with a history of cardiovascular disease (no history 0.06 vs history 0.14; P = .01).

Researchers found similar protective effects for memory and executive function.

Baker suggested one possible explanation for the positive effects of multivitamins may be the boost in micronutrients and essential minerals they provided.

"With nutrient-deficient diets plus a high prevalence of cardiovascular disease, diabetes, and other medical comorbidities that we know impact the bioavailability of these nutrients, we are possibly dealing with older adults who are at below optimum in terms of their essential micronutrients and minerals," she said.

"Even sub-optimum levels of micronutrients and essential minerals can have significant consequences for brain health," she added.

More Research Needed
Intriguing as the results may be, more work is needed before the findings could impact nutritional guidance, according to Maria C. Carrillo, PhD, chief science officer for the Alzheimer's Association.

"While the Alzheimer’s Association is encouraged by these results, we are not ready to recommend widespread use of a multivitamin supplement to reduce risk of cognitive decline in older adults," Carrillo said in a statement.

"For now, and until there is more data, people should talk with their healthcare providers about the benefits and risks of all dietary supplements, including multivitamins," she added.

Baker agreed, noting that the study was not designed to measure multivitamin use as a primary outcome. In addition, nearly 90% of the participants were non-Hispanic White, which is not representative of the overall population demographics.

The investigators are now designing another, larger trial that would include a more diverse participant pool. It will be aimed specifically at learning more about how and why multivitamins seem to offer a protective effect on cognition, Baker noted.

Pumping Iron Improves Longevity in Older Adults

Nancy A. Melville

October 07, 2022

Older adults who take part in regular weightlifting — either with or without moderate to vigorous aerobic activity — show significant reductions in all-cause and cardiovascular disease (CVD) mortality, with the strongest effects observed when the two types of exercise are combined, new research shows.

"The novel finding from our study is that weightlifting is independently associated with lower all-cause and CVD-specific mortality, regardless of aerobic activity," first author Jessica Gorzelitz, PhD, told Medscape Medical News.

"What's less surprising — but consistent and nonetheless noteworthy — is that weightlifting in combination with aerobic exercise provides the lowest...risk for mortality in older adults," added Gorzelitz, an assistant professor of health promotion in the Department of Health and Human Physiology at the University of Iowa in Iowa City.

Those who undertook weightlifting and aerobic exercise in combination had around a 40% lower risk of death than those who reported no moderate to vigorous aerobic activity or weightlifting. The findings were recently published online in the British Journal of Sports Medicine.

Physical activity guidelines generally recommend regular moderate to vigorous aerobic physical activity, in addition to at least 2 days per week of muscle-strengthening exercise for all major muscle groups for adults to improve health and boost longevity.

However, few observational studies have examined the association between muscle strengthening and mortality, and even fewer have looked specifically at the benefits of weightlifting, Gorzelitz said.

Benefit of Weightlifting Stronger in Women Than Men

To investigate, Gorzelitz and coauthors evaluated data on participants in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, which, initiated in 1993, and involved adults aged 55-74 at 10 US cancer centers.

Thirteen years into the trial, in 2006, participants completed follow-up questionnaires that included an assessment of weightlifting (not included in a baseline survey).

Among 99,713 participants involved in the current analysis, the mean age at the time of the follow-up questionnaire was 71.3 years. Participants had a mean body mass index (BMI) of 27.8 kg/m2 and 52.6% were women.

Only about a quarter of adults (23%) reported any weightlifting activity within the previous 12 months, with fewer, at 16%, reporting regular weightlifting of between one and six times per week.

Participants' physical aerobic activity was also assessed. Physical activity guidelines (2018) recommend at least 150-300 minutes per week of moderate-intensity aerobic physical activity or 75-150 minutes per week of vigorous intensity aerobic activity or an equal combination of the two. Overall, 23.6% of participants reported activity that met the guideline for moderate to vigorous physical activity, and 8% exceeded it.

Over a median follow-up of about 9 years, 28,477 deaths occurred.

Those reporting weightlifting had a 9% lower risk of combined all-cause mortality and CVD mortality, after adjustment for any moderate to vigorous physical activity (each hazard ratio [HR], 0.91).

Adults who met aerobic activity recommendations but did not weightlift had a 32% lower risk of all-cause mortality (HR, 0.68), while those who also reported weightlifting 1-2 times per week in addition to the aerobic activity had as much as a 41% lower risk of death (HR, 0.59) compared with adults reporting no moderate to vigorous aerobic activity or weightlifting.

The benefit of weightlifting in terms of cancer mortality was only observed without adjustment for moderate to vigorous physical activity, and was therefore considered null, which Gorzelitz noted was somewhat surprising. "We will examine this association further because there could still be a signal there," she said, noting other studies have shown that muscle strengthening activity is associated with lower cancer-specific mortality.

Of note, the benefit of weightlifting appeared stronger in women versus men, Gorzelitz said.

What Are the Mechanisms?

Underscoring that the results show only associations and not causation, Gorzelitz speculated that mechanisms behind a mortality benefit could include known favorable physiological changes of weightlifting.

"If people are weightlifting [to a degree] to reap strength benefits, we generally see improvement in body composition, including reductions in fat and improvements in lean tissue, and we know that those changes are associated with mortality, so it could be that the weightlifting is driving the strength or body composition," she said.

The full body response involved in weightlifting could also play a key role, she noted.

With weightlifting, "the muscles have to redirect more blood flow, the heart is pumping harder, the lungs breathe more and when the muscles are worked in that fashion, there could be other system-wide adaptations," she said.

Furthermore, social aspects could play a role, Gorzelitz observed.

"Unlike muscle strengthening [activities] that can be done in the home setting, weightlifting typically has to be done in recreational facilities or other community centers, and considering that this is an older adult population, that social interaction could be very key for preventing isolation."

Important limitations include that the study did not determine the nature of the weightlifting, including the duration of the weightlifting sessions or type of weight, which could feasibly range from small hand-held weights to heavier weightlifting.

The study also couldn't show how long participants had engaged in weightlifting in terms of months or years, hence, the duration needed to see a mortality benefit was not established.

Nevertheless, the study's finding that the group with the lowest benefits was the one reporting no aerobic or weightlifting exercise underscores the benefits of even small amounts of exercise.

"I think it's really important to promote the importance of adding muscle strengthening, but also of any physical activity," Gorzelitz said. "Start small, but something is better than nothing."

FLASH NEWS

PHARMACY COUNCIL OF NIGERIA (ESTABLISHMENT) ACT, 2022

This Act repeals the Pharmacists Council of Nigeria Act Cap. P17 Laws of the Federation of Nigeria, 2004 and enacts the Pharmacy Council of Nigeria (Establishment) Act, 2022 charged with the responsibility, amongst others, of regulating and controlling the education, training and practice of pharmacy and related matters in Nigeria.

https://placbillstrack.org/view.php?getid=917

https://independent.ng/fg-repeals-2006-aviation-act-as-buhari-signs-8-bills-into-law/

FG Repeals 2006 Aviation Act As Buhari Signs 8 Bills Into Law ABUJA - President Muhammadu Buhari has completed the repealing of the Civil Aviation Act, 2006 by signing into law the new Civil Aviation Bill (now an Act, 2022), as well as 7 other establishment Bills. According to a statement released on Monday by the Senior Special Assistant to the President on N...

Best Meds for Insomnia Identified?

July 15, 2022

Two drugs have emerged as the optimal medications for treating insomnia based on the "best-available evidence," but there are caveats.

In a comprehensive comparative-effectiveness analysis, lemborexant and eszopiclone showed the best efficacy, acceptability, and tolerability for acute and long-term insomnia treatment.

However, eszopiclone may cause substantial side effects — and safety data on lemborexant were inconclusive, the researchers note.

Not surprisingly, short-acting, intermediate-acting, and long-acting benzodiazepines were effective in the acute treatment of insomnia, but they have unfavorable tolerability and safety profiles, and there are no long-term data on these issues.

For many insomnia medications, there is a "striking" and "appalling" lack of long-term data, study investigator Andrea Cipriani, MD, PhD, professor of psychiatry, University of Oxford, Oxford, United Kingdom, noted during a press briefing.

"This is a call for regulators to raise the bar and ask for long-term data when companies submit an application for licensing insomnia drugs," Cipriani said.

The findings were published online July 16 in The Lancet.

Prevalent, Debilitating

Insomnia is highly prevalent, affecting up to 1 in 5 adults, and can have a profound impact on health, well-being, and productivity.

Sleep hygiene and cognitive-behavioral therapy for insomnia (CBT-I) are recommended first-line treatments, but they are often unavailable, which often lead patients and clinicians to turn to medications.

However, "insomnia drugs are not all created equal. Even within the same drug class there are differences," Cipriani said.

In a large-scale systematic review and network meta-analysis, the researchers analyzed data from 154 double-blind, randomized controlled trials of medications (licensed or not) used for acute and long-term treatment of insomnia in 44,089 adults (mean age, 51.7 years; 63% women).

Results showed, for the acute treatment of insomnia, benzodiazepines, doxylamine, eszopiclone, lemborexant, seltorexant, zolpidem, and zopiclone were more effective than placebo (standardized mean difference [SMD] range, 0.36 to 0.83; high-to-moderate certainty of evidence).

In addition, benzodiazepines, eszopiclone, zolpidem, and zopiclone were more effective than melatonin, ramelteon, and zaleplon (SMD, 0.27 to 0.71; moderate-to-very low certainty of evidence).

"Our results show that the melatonergic drugs melatonin and ramelteon are not really effective. The data do not support the regular use of these drugs," co-investigator Phil Cowen, PhD, professor of psychopharmacology, University of Oxford, said at the briefing.

Best Available Evidence

What little long-term data is available suggest eszopiclone and lemborexant are more effective than placebo. Plus, eszopiclone is more effective than ramelteon and zolpidem, but with "very low" certainty of evidence, the researchers report.

"There was insufficient evidence to support the prescription of benzodiazepines and zolpidem in long-term treatment," they write.

Another problem was lack of data on other important outcomes, they add.

"We wanted to look at hangover effects, daytime sleepiness, rebound effect, but often there was no data reported in trials. We need to collect data about these outcomes because they matter to clinicians and patients," Cipriani said.

Summing up, the researchers note the current findings represent the "best available evidence base to guide the choice about pharmacological treatment for insomnia disorder in adults and will assist in shared decision-making betweenpatients, carers, and their clinicians, as well as policy makers."

They caution, however, that all statements comparing the merits of one drug with another "should be tempered by the potential limitations of the current analysis, the quality of the available evidence, the characteristics of the patient populations, and the uncertainties that might result from choice of dose or treatment setting."

In addition, it is important to also consider nonpharmacologic treatments for insomnia disorder, as they are supported by "high-quality evidence and recommended as first-line treatment by guidelines," the investigator write.

Shared Decision-Making

In an accompanying editorial, Myrto Samara, MD, University of Thessaly, Larissa, Greece, agrees with the researchers that discussion with patients is key.

"For insomnia treatment, patient–physician shared decision-making is crucial to decide when a pharmacological intervention is deemed necessary and which drug [is] to be given by considering the trade-offs for efficacy and side effects," Samara writes.

Healthy' Plant-Based Diet Linked to Reduced Stroke Risk.

Erik Greb

March 12, 2021

Maintaining a healthy plant-based diet is associated with a lower risk for both total stroke and ischemic stroke, results from a study of three large cohorts suggest.

A plant-based diet was not associated with risk for hemorrhagic stroke, however, and the data also showed no association between a fully vegetarian diet and total stroke risk, the researchers report.

Most of the previous studies of this question defined a plant-based diet as a vegetarian diet, without differentiating the quality of plant foods, they note.

"In this study, we developed three versions of plant-based diet indices to assess the quality of plant-based dietary intake without excluding all animal foods and examined the quality of plant-based diet in relation to stroke risk," Megu Y. Baden, MD, PhD, postdoctoral research fellow at Harvard T. H. Chan School of Public Health, Boston, Massachusetts, told Medscape Medical News. "This approach is more similar to the strategies that many individuals are doing to increase plant-based foods and decrease animal-based foods in their diets."

The study was published online March 10 in Neurology.

Research suggests that plant-based diets reduce the risk for cardiovascular disease, but few studies have examined the effect of these diets on the risk for stroke. Moreover, published research on this question has yielded conflicting results, the researchers note. Two previous investigations showed no association between a vegetarian diet and risk for stroke mortality, but one study found that vegetarian patients were at increased risk for total and hemorrhagic stroke.

For their study, the researchers analyzed data from three large American cohorts. Two, the Nurses' Health Study (NHS) and the NHS II, included only women. The third, the Health Professionals Follow-Up Study (HPFS), included only men. Among exclusion criteria were history of cardiovascular disease or cancer at baseline, missing dietary data, and implausible intake of dietary energy.

Few Hemorrhagic Strokes

Participants in the three studies responded to questionnaires every 2 years, which provided information on lifestyle factors and medical history. Every 2 to 4 years, participants filled out a food frequency questionnaire.

To examine the populations' intake of plant-based foods, the investigators created a plant-based diet index (PDI), a healthful plant-based diet index (hPDI), and an unhealthful plant-based diet index (uPDI). They cited foods containing refined grains and added sugars as examples of unhealthful plant-based foods.

The researchers classified patients as vegetarian if they ate plant foods or other animal foods such as butter, dairy, or eggs but ate less than one serving per month of meat or fish. Other participants were considered nonvegetarians.

Medical records and the National Death Index were used to confirm incident and fatal stroke, respectively. The investigators examined total, ischemic, and hemorrhagic stroke separately.

The analysis included 73,890 women in the NHS, 92,352 women in the NHS II, and 43,266 men in the HPFS. In each cohort, participants with the highest PDI had lower BMI, engaged in more physical activity, were less likely to smoke, had higher healthy and lower unhealthy plant food consumption, and had lower animal food consumption compared with participants with the lowest PDI scores.

For participants in the highest PDI quintile, the hazard ratio (HR) for total stroke was lower compared to that of participants in the lowest quintile (HR, 0.94). Participants with the highest hPDI had a significantly lower risk for total stroke (HR, 0.90) than those with the lowest hPDI. Those with the highest uPDI had a slightly higher risk for total stroke than those with the lowest uPDI (HR, 1.05).

With regard to ischemic stroke, for participants with the highest PDI, the HR was 1.04, compared to those with the lowest PDI. For participants with the highest hPDI, the HR was 0.92, and for those with the highest uPDI, the HR was 0.96.

There was no association between PDI and risk for hemorrhagic stroke. "Fewer strokes were of hemorrhagic type, so our power may have been limited," said Baden.

They did not find an association between vegetarianism and total stroke risk, but this result could have followed from the small number of cases. The investigators did not examine the risk for stroke subtypes among vegetarians.

Diet Quality Matters

"The inconsistent results from prior studies looking at a vegetarian diet and stroke risk may in part be due to differences in the quality of plant-based diets — the proportion of heathy and less healthy plant-based foods — among those that follow vegetarian diets," said Baden. "In other words, no prior studies examined the dietary quality of vegetarian diets."

Research has indicated that plant-based foods are rich in nutrients that may reduce the risk for cardiovascular disease. These foods include dietary fiber, flavonoids, and polyphenols, which are more abundant in whole grains, fruits, vegetables, tea, and coffee. Consumption of these nutrients may be the mechanism through which a plant-based diet reduces the risk for stroke, they speculate.

The investigators would like to examine the mechanisms underlying the association between improved plant-based diet quality and lower stroke risk by assessing the metabolomic signatures or microbiomes of healthful and unhealthful plant-based diets, said Baden.

One of the study's strengths is its use of two large, well-established cohort studies of men and women, Kevin N. Sheth, MD, professor of neurology and neurosurgery at Yale School of Medicine and chief of neurocritical care and emergency neurology at Yale New Haven Hospital, New Haven, Connecticut, told Medscape Medical News. The findings, however, may not be generalizable to broad sections of society that are characterized by large socioeconomic and other disparities, he added.

"The results suggest that all plant-based diets are not the same and that further research is needed to identify the plant-based diets that are associated with reduction in stroke risk," said Sheth.

These findings underscore the importance of further clarifying which dietary strategies are most effective in preventing stroke, including diets that focus to various degrees on fruit, fiber, vegetables, and whole grains. "We need to understand what roles these kinds of diets may play in stroke risk in broader populations," said Sheth.

Also commenting for Medscape Medical News, Erica Camargo Faye, MD, PhD, a stroke neurologist at the Massachusetts General Hospital and an instructor in neurology at Harvard Medical School, Boston, Massachusetts, pointed out that the significant number of stroke endpoints in this study allowed for better assessment of associations with the outcomes of interest.

However, a large proportion of stroke endpoints (38%) were not classified as ischemic or hemorrhagic, which limits the assessment of associations between plant-based diets and stroke subtypes, she added.

"There is a large body of literature supporting the concept that the Mediterranean diet, DASH diet, and diets rich in fruits and vegetables reduce the risk of stroke," said Faye. "This study adds to these findings, demonstrating that the quality of plant-based diets also has a significant impact on the risk of stroke."

Future research could explore whether these findings remain significant in different racial and ethnic populations, Faye added. Another relevant question is whether healthful plant-based diets have a stronger effect on the risk for ischemic stroke or the risk for hemorrhagic stroke.

"Considering prior conflicting data regarding the risk of stroke in relation to vegetarian diets, studying how the quality of vegetarian diets (ie, healthful vs unhealthful plant-based diets) impacts the risk of stroke is an important question to address," she concluded.