For people who had high blood pressure readings only when sitting (normal readings while lying down), there was no statistically significant difference in risk of coronary heart disease, heart failure, or stroke compared to people with normal blood pressure. The only statistically significant differences were a 41 percent higher risk of fatal coronary heart disease (compared to the 78 percent seen in those with high readings lying down) and an 11 percent higher risk of all-cause mortality.
(In this study, high blood pressure readings were defined for both positions as those with systolic readings (the top number) of 130 mm Hg or greater or diastolic readings (the bottom number) of 80 mm Hg or greater.)
The people with the highest risks across the board were those who had high blood pressure readings while both sitting and lying down.
“These findings suggest that measuring supine [lying down] BP may be useful for identifying elevated BP and latent CVD risk,” the researchers conclude.
Strengths and hypotheses
For now, the findings should be considered preliminary. Such an analysis and finding should be repeated with a different group of people to confirm the link. And as to the bigger question of whether using medication to lower supine blood pressure (rather than seated blood pressure) is more effective at reducing risk, it’s likely that clinical trials will be necessary.
Still, the analysis had some notable strengths that make the findings attention-worthy. The study’s size and design are robust. Researchers tapped into data from the Atherosclerosis Risk in Communities (ARIC) study, a study established in 1987 with middle-aged people living in one of four US communities (Forsyth County, North Carolina; Jackson, Mississippi; suburban Minneapolis, Minnesota; and Washington County, Maryland).
Two big, somewhat conflicting studies on alcohol risks will influence new guidelines.
Heavy drinking is clearly bad for your health. But it’s long been questioned whether moderate drinking is also risky—and, if so, how risky, exactly.
Health researchers have consistently found links between alcohol consumption and several types of cancers (namely mouth, throat, colon, rectal, liver, and breast), as well as liver diseases, injuries, and traffic accidents. But nailing down the health risks from the lower levels of drinking has been tricky. For one, much of the data on moderate drinking is from observational studies in different countries, cultures, and populations. They cannot determine if alcohol is the direct cause of any given association, and they may be swayed by other lifestyle factors. The resulting data can be noisy and inconsistent.
Moreover, many studies rely on people to self-report whether they drink and, if so, how much, which is problematic because people may not accurately assess and/or report how much they actually drink. A related problem is that studies in the past often compared drinkers to people who said they didn’t drink. But, the trouble is, non-drinking groups are often some mix of people who are lifelong abstainers and people who used to drink but quit for some reason—maybe because of health effects. This latter group has the potential to have lingering health effects from their drinking days, which could skew any comparisons looking for health differences.
Then there’s the larger, common problem with any research focused on food or beverages: some have been sponsored or somehow swayed by industry, casting suspicion on the findings, particularly the ones indicating benefits. This has been a clear problem for alcohol research. For instance, in 2018, the National Institutes of Health shut down a $100 million trial aimed at assessing the health effects (and potential benefits) of moderate drinking after it came to light that much of the funding was solicited from the alcohol industry. There was a lot of questionable communication between NIH scientists and alcohol industry representatives.
With all of that in the background, there’s been clamorous debate about how much risk, if any, people are swallowing with their evening cocktail, gameday beer, or wine with dinner.
Currently, the US dietary guidance recommends that if adults drink, they should stick to drinking in moderation, defined as “alcohol intake to two drinks or fewer in a day for men and one drink or fewer in a day for women.” But recently, health experts in the US and abroad have started calling for lower limits, noting that more data has poured in that fortifies links to cancers and other risks. In 2023, for instance, Canada released recommendations that people limit their alcohol consumption to two drinks or fewer per week—that’s down significantly from the previously recommended limit of 10 drinks per week for women and 15 drinks per week for men.
Two reviews
Now, it’s America’s turn to decide if they’ll set the bar lower, too. This year, the US will update its dietary guidelines, which are carried out by the Department of Health and Human Services and the Department of Agriculture every five years. The federal government has requested two big scientific reviews to assess the current knowledge of the health effects of alcohol, which will both inform any potential revisions to the alcohol guidelines. Now, both studies have been released and are open for discussion.
One is from the National Academies of Sciences, Engineering, and Medicine (the National Academies), which was tasked by Congress to review the current evidence on alcohol with a focus on how moderate drinking potentially affects a specific set of health outcomes. The review compared health outcomes in moderate drinkers with those of lifelong abstainers. For the review, the National Academies set up a committee of 14 experts.
Based on top-line takeaways and tone, the two reports seem to have very different findings. While the National Academies review found a mix of benefits and harms from moderate drinking (one drink per day for women, and two per day for men), the ICCPUD review suggested that even the smallest amounts of alcohol (one drink per week) increased risk of death and various diseases. However, a closer look at the data shows they have some common ground.
The National Academies review
First, for the National Academies’ review, experts found sufficient evidence to assess the effects of moderate drinking on all-cause mortality, certain cancers, and cardiovascular risks. On the other hand, the reviewers found insufficient evidence to assess moderate drinking’s impact on weight changes, neurocognition, and lactation-related risks.
For all-cause mortality, a meta-analysis of data from eight studies found that moderate drinkers had a 16 percent lower risk of all-cause mortality (death from any cause) compared with lifelong abstainers. A meta-analysis of three studies suggested the risk of all-cause mortality was 23 percent lower for females who drank moderately compared to never-drinking females. Data from four studies indicated that moderate drinking males had a 16 percent lower risk of all-cause mortality than never-drinking males. Additional analyses found that the risk of all-cause mortality was 20 percent lower for moderate drinkers less than age 60 and 18 percent lower for moderate drinkers age 60 and up.
“Based on data from the eight eligible studies from 2019 to 2023, the committee concludes that compared with never consuming alcohol, moderate alcohol consumption is associated with lower all-cause mortality,” the review states. The reviewers rated the conclusion as having “moderate certainty.”
Cancer and cardiovascular disease
For a look at cancer risks, a meta-analysis of four studies on breast cancer found that moderate drinkers had an overall 10 percent higher risk than non-drinkers. An additional analysis of seven studies found that for every 10 to 14 grams of alcohol (0.7 to one standard drink) consumed per day, there was a 5 percent higher risk of breast cancer. The data indicated that people who drank higher amounts of alcohol within the moderate range had higher risks than those who drank lower amounts in the moderate range (for instance, one drink a day versus 0.5 drinks a day).
For context, the average lifetime risk of being diagnosed with breast cancer in non-drinking females is about 11 to 12 percent. A 10 percent relative increase in risk would raise a person’s absolute risk to around 12 to 13 percent. The average lifetime risk of any female dying of breast cancer is 2.5 percent.
Overall, the reviewers concluded that “consuming a moderate amount of alcohol was associated with a higher risk of breast cancer,” and the conclusion was rated as having moderate certainty.
A meta-analysis on colorectal cancer risks found a “statistically nonsignificant higher risk” in moderate drinkers compared to non-drinkers. However, studies looking at alcohol consumption at the highest levels of moderate drinking for males (e.g., two drinks per day) suggested a higher risk compared to males who drank lower amounts of alcohol in the moderate range (one drink per day).
The review concluded that there was insufficient evidence to support a link between moderate drinking and oral cavity, pharyngeal, esophageal, and laryngeal cancers.
Finally, for cardiovascular risks, meta-analyses found moderate drinking was associated with a 22 percent lower risk of heart attacks and an 11 percent lower risk of stroke (driven by lower risk of ischemic stroke, specifically). The reviewers rated these associations as low certainty, though, after noting that there was some concern for risk of bias in the studies.
For cardiovascular disease mortality, meta-analyses of four studies found an 18 percent lower risk of death among moderate drinkers compared with non-drinkers. Broken down, there was a 23 percent lower risk in female drinkers and 18 percent lower risk in male drinkers. The lower risk of cardiovascular disease mortality was rated as moderate certainty.
The ICCPUD review
The ICCPUD subcommittee’s report offered a darker outlook on moderate drinking, concluding that “alcohol use is associated with increased mortality for seven types of cancer (colorectal, female breast, liver, oral cavity, pharynx, larynx, esophagus [squamous cell type]),” and “increased risk for these cancers begins with any alcohol use and increases with higher levels of use.”
The review modeled lifetime risks of cancer and death and relative risks for a long list of problems, including infectious diseases, non-communicable diseases, and injuries. Also, it didn’t just focus on non-drinkers versus moderate drinkers, but it assessed the relative risk of six levels of drinking: one drink a week; two drinks a week; three drinks a week; seven drinks a week (one a day); 14 drinks a week (two a day), and 21 drinks a week (three a day).
Overall, the analysis is very much a rough draft. There are some places where information is missing, and some of the figures are mislabeled and difficult to read. There are two figures labeled Figure 6, for instance and Figure 7 (which may be Figure 8), is a graph that doesn’t have a Y-axis, making it difficult to interpret. The study also doesn’t discuss the level of potential bias of individual studies in its analyses. It also doesn’t make note of statistically insignificant results, nor comment on the certainty of any of its findings.
For instance, the top-line summary states: “In the United States, males and females have a 1 in 1,000 risk of dying from alcohol use if they consume more than 7 drinks per week. This risk increases to 1 in 100 if they consume more than 9 drinks per week.” But a look at the modeling behind these estimates indicates the cutoffs of when drinkers would reach a 0.1 percent or 1 percent risk of dying from alcohol use are broad. For males, a 0.1 percent lifetime risk of an alcohol-attributed death is reached at 6.5 standard drinks, with a 95 percent confidence interval spanning less than one drink per week and 13.5 drinks per week. “This lifetime risk rose to 1 in 100 people above 8.5 drinks per week,” the text reads, but the confidence interval is again between one and 14 drinks per week. So, basically, at anywhere between about one and 14 drinks a week, a male’s lifetime risk of dying from alcohol may be either 0.1 or 1 percent, according to this modeling.
Death risks
Regarding risk of death, the study did not look at all-cause mortality, like the National Academies review. Instead, it focused on deaths from causes specifically linked to alcohol. For both males and females, modeling indicated that the total lifetime risk of any alcohol-attributed death for people who consumed one, two, three, or seven drinks per week was statistically non-significant (the confidence intervals for each calculation spanned zero). Among those who have 14 drinks per week, the total lifetime risk of death was about 4 in 100 from all causes, with unintentional injuries being the biggest contributor for males and liver diseases being the biggest contributor for females. Among those who have 21 drinks per week, the risk of death was about 7 in 100 for males and 8 in 100 for females. Unintentional injuries and liver diseases were again the biggest contributors to the risk.
Some experts have speculated that the lower risk of all-cause mortality found in the National Academies’ analysis (which has been seen in previous studies) may be due to healthy lifestyle patterns among people who drink moderately rather than the protective effects of alcohol. The line of thinking would suggest that healthy lifestyle choices, like regular exercise and a healthy diet, can negate certain risks, including the potential risks of alcohol. However, the ICCPUD emphasizes the reverse argument, noting that poor health choices would likely exacerbate the risks of alcohol. “[A]lcohol would have a greater impact on the health of people who smoke, have poor diets, engage in low physical activity, are obese, have hepatitis infection, or have a family history of specific diseases than it would other individuals.”
Relative risks
In terms of relative risk of the range of conditions, generally, the ICCPUD study found small, if any, increases in risk at the three lowest levels of drinking, with risks rising with higher levels. The study’s finding of breast cancer risk was in line with the National Academies’ review. ICCPUD found that pre-menopausal females who drink moderately (one drink per day) had a 6 percent higher risk of breast cancer than non-drinkers, while post-menopausal moderate drinkers had a 17 percent higher risk. (You can see the complete set of relative risk estimates in Table A6 beginning on page 70 of the report.)
For some cancers, moderate drinking raised the risk substantially. For instance, males who have two drinks per day see their risk of esophageal cancer more than double. But, it’s important to note that the absolute risk for many of these cancers is small to begin with. The average risk of esophageal cancer in men is 0.8 percent, according to the American Cancer Society. With the increased risk from moderate drinking, it would be below 2 percent. Still, alcohol consumption increased the risks of nearly all the cancers examined, with the higher levels of alcohol consumption having the highest risk.
As for cardiovascular risks, ICCPUD’s review found low risk in several of the categories. The risk of ischemic heart disease was lower than that of nondrinkers at all six drinking levels. The risk of ischemic stroke was lower among drinkers who had one, two, three, or seven drinks per week compared to non-drinkers. At 14 and 21 drinks per week, the risk of ischemic stroke rose by 8 percent.
Beth is Ars Technica’s Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes.
Enlarge/ A cannabis flower is seen at East End Flower Farm, in Mattituck, New York, on November 16, 2023.
Survey data collected from more than 430,000 US adults over multiple years suggests a strong, statistically significant link between the use of cannabis and an increased risk of cardiovascular disease, specifically heart attack and stroke.
The open-access study, published this week in Journal of the American Heart Association, found that people who used cannabis every day had 25 percent higher odds of having a heart attack and 42 percent higher odds of having a stroke compared with those who did not use cannabis at all.
But, the national survey data—collected between 2016 and 2020—also contained data on people who used cannabis less frequently than daily. Survey respondents were asked how many days in the past 30 days they used cannabis, which allowed researchers to estimate the odds of cardiovascular disease along the whole spectrum of cannabis use. And they found near-linear dose-responses, with more days of use per month associated with higher risk.
This isn’t the first time that researchers have found an association between cannabis use and cardiovascular disease, but the study is among the largest to date—with a sample size between three and 17 times larger than previous studies. Its size not only added weight to the link but also allowed the researchers to drill down into other risk factors for cardiovascular disease.
Clear link
One common complicating factor is that people who use cannabis also often use tobacco products, which carry their own increased risk for cardiovascular disease. In the new study, led by Abra Jeffers of Massachusetts General Hospital, researchers were able to do two additional analyses: one that looked at cardiovascular disease risk in people who use cannabis but had never used tobacco products and a second one that looked at people who used cannabis but had never used tobacco products or e-cigarettes. Without tobacco use, the higher odds of heart attack and stroke persisted for people who used cannabis. For those without tobacco or e-cigarette use, only the higher odds of stroke remained.
The researchers also looked at age, another complicating factor. Heart disease can take years or decades to develop, but people who use cannabis tend to skew younger. The 434,104 people who took the survey ranged from age 18 to 74, and the analyses adjusted for other health factors, including alcohol use, diabetes, body mass index, and physical activity. When the researchers looked at just the adults who would be considered on the young side for developing cardiovascular disease (less than 55 for men and less than 65 for women), they found that cannabis use also increased the odds of premature cardiovascular disease—and again the link was independent of tobacco and e-cigarette use.
In all, the researchers concluded that “these data suggest that cannabis use may be a risk factor for cardiovascular disease and may be a risk factor for premature cardiovascular disease,” they wrote. This is particularly concerning, they add, because of the growing acceptance and use of cannabis in the US and a decline in perceived health risks.
Limitations
But, the study has limitations that preclude a firm conclusion that cannabis is causing cardiovascular disease. The study relies on self-reported data on both cardiovascular health and cannabis use—both of which can be unreliable. It also relied on data collected at a specific point in time. It’s possible that some people turned to cannabis use after developing cardiovascular disease rather than before, for instance. The survey data can’t make that distinction; it’s only making an association. The authors note that cardiovascular disease, heart attack, and stroke have not previously been identified as major reasons that people use cannabis. This lessens the reverse concern that cardiovascular disease is increasing the odds of cannabis use. But, the researchers do note that many studies have linked the use of cannabis to chronic pain, insomnia, and anxiety—all of which have also been associated with cardiovascular disease. Last, the survey data does not include data on people’s actual cardiovascular health, such as blood pressure and lipid profiles.
Another wrinkle to the study is the route of cannabis use and how it may play a role in the link to cardiovascular disease. About 74 percent of cannabis users in the study reported smoking cannabis, which could potentially increase the risk of cardiovascular disease much the same way tobacco cigarettes do—a result of inhaling particulate matter into the lungs. It’s unclear if edible cannabis products would weaken the association seen in the study.
But, the authors note that there is a biologically plausible link between cannabis and cardiovascular disease. Cell signaling receptors that detect components of cannabis (endocannabinoid receptors) are ubiquitous throughout the cardiovascular system, the researchers note. And the key psychoactive substance in cannabis, Tetrahydrocannabinol (THC), can increase blood pressure and heart rate during use.
Enlarge/ A shopper looks at a meat display on June 20, 2022, at the Market 32 Supermarket in South Burlington, Vermont. Niacin can be found in foods such as red meat, poultry, fish, fortified cereals and breads, brown rice, nuts, legumes, and bananas.
The deadly epidemic led to voluntary—and eventually mandatory—fortification of wheat and other cereals with niacin (aka Vitamin B3). By the middle of the century, pellagra nearly vanished from the US. But, decades later, the public health triumph may be backfiring. With Americans’ diets more reliant than ever on processed, niacin-fortified foods, the average niacin intake in the US is now nearing what’s considered the tolerable upper limit of the nutrient, according to a federal health survey. And an extensive study recently published in Nature Medicine suggests that those excess amounts of niacin may be exacerbating cardiovascular disease, increasing risks of heart attacks, strokes, and death.
The study, led by Stanley Hazen, chair of Cardiovascular and Metabolic Sciences at Cleveland Clinic’s Lerner Research Institute, connected high blood levels of a breakdown product of niacin—and to a lesser extent, tryptophan—to an elevated risk of major adverse cardiovascular events (MACE). And this elevated risk appears to be independent of known risk factors for those events, such as high cholesterol.
“What’s exciting about these results is that this pathway appears to be a previously unrecognized yet significant contributor to the development of cardiovascular disease,” Hazen said in an announcement of the study. It can be measured, he added, and one day could be a new avenue for treatment and prevention.
Metabolite fishing
Hazen and his colleagues didn’t start out suspecting niacin could be a culprit in cardiovascular disease. They arrived at that point after fishing through patients’ blood plasma. The researchers were carefully inventorying metabolites in the fasting plasma of 1,162 patients who had been evaluated for cardiovascular disease. They were looking for anything that might be linked to a heightened risk of heart attack, stroke, or death in a three-year period that couldn’t entirely be explained by other risk factors. Despite advances in identifying and treating cardiovascular disease, researchers have noted that some patients continue to be at risk of serious cardiovascular events despite having their traditional risk factors treated and controlled. Hazen and his colleagues wanted to know why.
The metabolomic trawling came up with an unknown metabolite (signature C7H9O2N2) that was significantly linked to having a MACE in the three-year period. People who had higher levels of this metabolite circulating in their systems were within the top 75th percentile for relative MACE risk in the cohort. Further work identified the metabolite as actually being two related molecules: 2PY (N1-methyl-2-pyridone-5-carboxamide) and 4PY (N1-methyl-4-pyridone -3-carboxamide)—both the final breakdown products of niacin.
