An estimated 1.4 billion adults worldwide between the ages of 30 and 79 have high blood pressure (hypertension), a major contributor to illness and death. Although medications that lower blood pressure are proven to reduce the risk of cardiovascular complications, approximately half of patients do not take their prescriptions as directed.

“We have evidence that poor adherence to antihypertensive medication is associated with worse outcomes,” explained presenter, Miss Qianqian Yang from the University of Oxford, UK. “However, previous data has come from observational studies and could be confounded by other factors. We undertook an analysis of randomized trial data to assess the true impact of adherence on the benefits of antihypertensive treatment.”

Major Study Examines the Impact of Missed Blood Pressure Medication

To better understand how consistently taking medication affects its benefits, researchers analyzed individual patient data from 91,339 participants across nine clinical trials. Each trial compared a blood pressure treatment (intervention group) with an alternative approach (comparator group: either placebo or a less-intensive regimen).

The researchers divided participants into two categories based on how closely they followed their prescribed treatment. Those who took at least 80% of their assigned medication were considered to have higher adherence, while those who took less than 80% were placed in the lower adherence group.

Even with the regular monitoring and structured conditions of clinical trials, patients became less consistent about taking their medication as time passed.

“A decline in adherence over time was apparent, even in the structured setting of trials,” noted Miss Yang. Overall, 88% of participants met the higher adherence threshold during the first year, but that figure had dropped to just 79% by the fifth year.

Skipping Blood Pressure Pills Reduces Treatment Benefits

The difference in medication adherence was reflected in how much patients’ blood pressure improved.

Among participants with higher adherence, systolic blood pressure, the top number in a blood pressure reading, was 5.2 mmHg lower in the intervention group than in the comparator group. For those with lower adherence, the difference was considerably smaller at just 3.0 mmHg.

Researchers then examined whether these differences translated into protection against major cardiovascular problems. The outcomes included strokes, heart attacks (myocardial infarction), ischemic heart disease, and heart failure that resulted in hospitalization or death.

The findings revealed a striking contrast. Among patients who consistently followed their treatment plans, the intervention group experienced an 11% lower incidence of major cardiovascular events compared with the comparator group. However, among patients with lower adherence, there was no statistically significant reduction in these events.

“Notably, our results reinforce the saying that ‘drugs don’t work in patients who don’t take them.’ Patients with lower adherence derived little or no cardiovascular benefit, whereas those with higher adherence had greater reductions in blood pressure and prevention of cardiovascular events,” said Miss Yang.

Helping Patients Get Lifesaving Heart Protection

The researchers believe that helping people take their medication consistently should become a greater priority in the treatment of high blood pressure. They recommend more routine assessments of medication adherence, along with better patient education and practical strategies to make treatment easier to follow.

Possible approaches include simplifying medication schedules, combining multiple treatments into a single pill, and prescribing longer-acting drugs that can help limit the consequences of an occasional missed dose.

Professor Felix Mahfoud, Chair of the ESC Communication Committee, emphasized that missed medication has received too little attention as a contributor to poorly controlled blood pressure.

“For years, we have neglected non-adherence to medication as a cause for uncontrolled hypertension. Assessment of adherence should become a routine part of hypertension care so patients do not miss out on life-saving benefits. As healthcare providers, we are here to have open, non-judgmental conversations with our patients about any barriers they may have to taking medication, to help improve adherence.”

The research, known as the Alcohol Intake and Health Study, was originally commissioned by the U.S. federal government to help shape updated national dietary recommendations. Researchers estimated that people who consume an average of 14 alcoholic drinks per week face a 1 in 25 lifetime risk of dying from alcohol-related causes. By comparison, consuming up to seven drinks weekly was linked to only small increases in risk for most health conditions.

“Even low levels of alcohol use come with health risks,” says lead study author Kevin Shield, Ph.D., an associate professor at the University of Toronto and a senior scientist who leads the World Health Organization (WHO)/Pan American Health Organization (PAHO) Collaborating Centre in Addiction and Mental Health. “And that risk continues to increase the more someone drinks.”

How Scientists Measured the Health Risks of Alcohol

To better understand the long-term consequences of drinking, Shield and his colleagues in the United States and Canada investigated how alcohol consumption over a lifetime contributes to disease and premature death among Americans.

Medical experts first examined more than 7,200 scientific publications covering illnesses and injuries associated with alcohol. Using this evidence, they estimated the risks for individual health conditions and combined those findings with large national health data sets. Statistical models then allowed the team to calculate how different levels of alcohol consumption affect the likelihood of developing serious health problems or dying prematurely.

The findings provide specific estimates that are missing from the latest U.S. Dietary Guidelines. The updated recommendations simply encourage Americans to “limit alcoholic beverages” without identifying a particular consumption threshold. Earlier versions advised men to drink no more than two alcoholic beverages per day and women no more than one.

“While the new U.S. Dietary Guidelines contain a useful ‘less-is-best’ message, they provide no quantitative framework. Our study was designed to do just that across the drinking spectrum,” says study co-author Timothy Naimi, M.D., M.P.H., director of the University of Victoria’s Canadian Institute for Substance Use Research and an adjunct professor at Boston University.

“It turns out that two drinks per day, which might be considered ‘moderate’ from a social standpoint, is associated with a substantially elevated risk of a premature death caused by alcohol,” explains Naimi.

Moderate Drinking Offers No Significant Overall Health Benefits

The researchers looked beyond the risk of premature death to examine alcohol’s connection to a wide range of immediate and long-term health problems. These included cancers (e.g., esophageal, oral, and breast), cardiovascular disease, liver disease, and injuries.

One of the study’s most important findings challenges the longstanding belief that consuming small amounts of alcohol can improve health, particularly heart health.

“We did not observe a significant protective effect of alcohol on health at any level of consumption,” says Shield. “At low levels, alcohol may be associated with a reduced risk of ischemic heart disease and stroke. But when you look across the full range of health outcomes, including cancer and other chronic diseases, those potential benefits are outweighed by the risks even at 7 drinks per week.”

In other words, while some studies have suggested that light drinking may benefit certain aspects of cardiovascular health, those possible advantages do not translate into an overall health benefit once alcohol’s links to cancer and other diseases are taken into account.

Why Individual Alcohol Risks Can Differ

Although the analysis drew on extensive scientific evidence, the researchers emphasize that its estimates describe risks across populations rather than predicting precisely what will happen to any particular person.

Shield says the statistical calculations relied on “the best possible data.” However, he cautions that individual circumstances can substantially influence the results.

“However, we can’t assume that means one person’s individual health risk is the same as what is reported here — that depends on other factors like lifestyle, genetics, drinking patterns, and other choices that differ person to person.”

To estimate alcohol’s overall impact, the researchers calculated risks for health conditions already known to be caused by alcohol and combined them into a broader assessment. However, scientists are continuing to investigate additional possible consequences of drinking, including emerging evidence connecting alcohol consumption to pancreatic cancer.

“Understanding those relationships, and how much alcohol contributes to those risks, is an area that still needs further work,” says Shield.

What the Findings Mean for U.S. Drinking Guidelines

The results suggest that alcohol-related health risks become more pronounced when consumption exceeds one drink per day, regardless of whether the person is male or female. This provides a more specific reference point for people trying to understand how their drinking habits might affect their long-term health.

Rather than suggesting that any particular amount is completely safe, the findings show how risks increase with greater consumption and why drinking less generally reduces exposure to alcohol-related harm.

“Having a clearer threshold helps people better understand what level of drinking is associated with increased risk and make more informed decisions when drinking,” says Shield.

The study has also raised questions about how scientific evidence was incorporated into federal dietary recommendations.

In an accompanying editorial, Robert M. Vincent, a former Associate Administrator for the U.S. Substance Abuse and Mental Health Services Administration, offers his perspective on the circumstances surrounding the research and its role in the development of national guidance.

“The Alcohol Intake and Health report was explicitly invited to inform alcohol guidance during development of the Dietary Guidelines for Americans, 2025-2030,” he writes. “Despite the study’s adherence to its mandate, its findings were sidelined.”

The findings, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, were based on genetic data from more than 13,500 participants in the landmark ASPREE Trial (Aspirin in Reducing Events in the Elderly). Scientists examined whether differences in participants’ genes could help explain why aspirin might affect dementia risk differently from one person to another.

Aspirin Linked to 70% Lower Dementia Risk in Certain People

The most striking results involved genes associated with platelet count. Platelets are small components of the blood that help form clots, and researchers wanted to determine whether genetic variations related to platelet levels could influence aspirin’s potential effects on dementia.

After assigning participants genetic scores associated with platelet count, the team compared dementia rates among those who received aspirin and those given a placebo.

Among people in the highest 20 percent of platelet count genetic scores, just 1 percent of aspirin users developed dementia, compared with 3.3 percent of participants taking a placebo. That difference translates to approximately a 70 percent lower relative risk of dementia among those receiving aspirin.

However, the apparent benefit was accompanied by a significant safety concern. In the same genetic group, 4.4 percent of aspirin users experienced major bleeding, compared with 2.1 percent of those receiving a placebo.

A Genetic Clue Could Change Dementia Prevention

Lead author Dr. Peter Fransquet, a Research Fellow at Monash’s School of Public Health and Preventive Medicine, said the results suggest that a person’s genetic makeup could eventually play an important role in determining which dementia prevention strategies are most appropriate.

“Previous trials found aspirin didn’t prevent dementia when everyone was considered together,” Dr. Fransquet said.

“Our findings suggest there may be more to the story.

“In people with this particular genetic profile, we saw substantially fewer cases of dementia among those taking aspirin.

“It raises the possibility that genetics could one day help us identify who may benefit from a preventive treatment, rather than taking a one-size-fits-all approach.”

The possibility of more targeted prevention is especially important as dementia becomes increasingly common. Dementia Australia estimates that approximately 446,500 people in Australia are living with the condition in 2026. That number is expected to exceed one million by 2065.

Blood Platelets Reveal an Unexpected Dementia Connection

Previous research has connected dementia with platelet activation and aggregation, the processes through which platelets become active and stick together. However, scientists have had a less complete understanding of how a person’s overall platelet count might relate to dementia.

The new findings point toward platelet biology as a potentially important area of investigation. Notably, the genetic association identified by researchers did not involve the well-established genetic risk factors typically linked to Alzheimer’s disease and other forms of dementia.

“What’s particularly interesting is that the signal wasn’t linked to the established genetic risk factors for Alzheimer’s disease and dementia,” Dr. Fransquet said.

“Instead, it’s pointing us towards platelet biology and gives us a new avenue to investigate.”

Why More Research Is Needed Before Taking Aspirin

Although the findings suggest that aspirin could have different effects depending on a person’s genes, researchers emphasize that the results must be confirmed before they can guide medical recommendations.

The next step is to investigate whether the association appears in other populations. Scientists would then need to conduct a clinical trial specifically involving people with the genetic profile identified in the analysis.

“We now need to confirm the finding in other studies and ultimately test it in a trial designed specifically for people with this genetic profile.

“People shouldn’t start taking aspirin to prevent dementia on the basis of this study without consulting with their doctor, particularly given the increased risk of serious bleeding.

“If it holds up, the fact that aspirin is already cheap and widely available could make personalized dementia prevention a real possibility.”