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Dietary factors linked to high proportion of deaths from stroke, heart disease, type 2 diabetes
Dietary factors contributed to a “substantial” portion of deaths from stroke, heart disease and type 2 diabetes, according to findings published in JAMA.
Although dietary factors attributed to these deaths, the number that occurred between 2002 and 2012 decreased by one-quarter.
“These results should help identify priorities, guide public health planning and inform strategies to alter dietary habits and improve health,” Renata Micha, RD, PhD, research assistant professor at the Friedman School of Nutrition Science and Policy at Tufts University, and colleagues wrote.
Researchers utilized a comparative risk assessment model to estimate cardiometabolic deaths that related to substandard intakes of 10 dietary factors in the United States. The model also featured information that focused on dietary habits and population demographics by age, sex, race and education; dietary factors relating to stroke, heart disease or type 2 diabetes mortality; ideal intake for each of the 10 dietary factors and the number of cardiometabolic deaths by age, sex, race and education.
The 10 dietary factors — consumption of fruits, vegetables, nuts or seeds, whole grains, unprocessed red meats, processed meats, sugar-sweetened beverages, polyunsaturated fats, seafood omega-3 fats and sodium — were selected out of a pool of 17 factors that had associations with stroke, CHD, BMI, type 2 diabetes or systolic BP. Factors that overlapped with other effects and factors with inadequate evidence were removed.
Researchers analyzed participants from the 1999-2000 and 2001-2002 National Health and Nutrition Examination Survey (n = 8,104; 48% men), as well as the 2009-2010 and 2011-2012 NHANES (n = 8,516; 48% men).
According to Micha and colleagues, intake of each dietary factor was suboptimal for 2002 and 2012.
In 2012, there were 702,308 cardiometabolic deaths among adults in the United States. Of those, 506,100 occurred from heart disease, 67,914 from type 2 diabetes and 128,294 from stroke.
Nearly one in two deaths (318,656 [45.4%]; 95% uncertainty interval (UI), 306,064-329,755) were associated with suboptimal intakes of the 10 dietary factors in 2012. High sodium was related to the largest number of diet-related cardiometabolic deaths (66,508; 9.5%), followed by the low intake of nuts and seeds (59,374; 8.5%) and high amounts of processed meats (57,766; 8.2%). The lowest number of deaths were caused by low intake of polyunsaturated fats (16,025; 2.3%) and high intake of unprocessed red meats (2,869; 0.4%).
The highest death rates among those with CHD were linked to a low intake of nuts and seeds (54,591; 14.7%), the researchers wrote. Stroke-related death was most often attributed to low consumption of vegetables (28,039; 21.9%) and fruits (28,741; 22.4%). Death caused by hypertensive heart disease was most often attributable to high levels of sodium (7,505; 21.4%), and death from type 2 diabetes was most commonly associated with a high intake of processed meats (11,900; 17.5%).
Rates of cardiometabolic-related death were higher in men than women, predominately due to unhealthier diets. A significant difference between sexes was noted for processed meats, in which 10.8% of cardiometabolic deaths were seen in men vs. 5.4% in women (difference, 5.4 percentage points; 95% UI, 2.3-8.3), followed by sugar-sweetened beverages (9.3% in men vs. 5.3% in women; difference, 3.9 percentage points; 95% UI, 2.3-5.4). High intake of processed meats was most commonly associated with death in men (38,632; 10.8%); for women, it was excess sodium (30,281; 8.8%).
In 2012, insufficient diet contributed to 41.8% of cardiometabolic-related deaths in women and 48.6% in men (difference, 6.9 percentage points; 95% UI, 3.3-10.1).
In participants aged 25 to 64 years, processed meats and sugar-sweetened beverages were the top dietary factors associated with cardiometabolic mortality, whereas dietary factors most often associated with mortality in those aged at least 65 years were low intake of nuts and seeds, insufficient levels of vegetables and excess sodium. An inadequate diet was the cause for 64.2% of cardiometabolic deaths among those aged 25 to 32 years, and 35.7% of deaths among those older than 75 years.
Researchers found that cardiometabolic death rates among black and Hispanic participants were higher for the majority of the dietary factors included in the study. Sugar-sweetened beverages were the leading cause of cardiometabolic death among black participants (12.6% vs. 6.4% for white participants). The leading dietary factor for death in Hispanic participants was a low intake of nuts and seeds (11.7% vs. 7.9% for white participants). Suboptimal diets were attributed to cardiometabolic death for 53.1% of black participants, 50% of Hispanic participants and 42.8% of white participants who died.
Those with low or medium levels of education had higher rates of cardiometabolic deaths compared with participants with high education.
However, Micha and colleagues wrote, cardiometabolic deaths throughout the United States decreased by 26.5% between 2002 and 2012 and the consumption of certain dietary factors, including nuts and seeds, sugar-sweetened beverages, fruits and whole grains improved nationally.
“These findings should be considered estimates of national cardiometabolic mortality related to suboptimal intakes of these 10 dietary factors, and potential effects of specific interventions should be evaluated in future studies,” Micha and colleagues wrote. – by Darlene Dobkowski
Disclosure: Micha reports no relevant financial disclosures. Another researcher reports receiving personal fees from AstraZeneca, Boston Heart Diagnostics, DSM, Global Organization for EPA and DHA Omega-3, Haas Avocado board, Life Sciences Research Organization and UpToDate.
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We have been counseling patients for years based on the evidence that a predominately plant-based dietary pattern that is high in fruits, vegetables, nuts and seeds and low in saturated and trans fats will reduce risk for CVD. A heart-healthy diet can include some lean protein, especially from fish, which is low in saturated fat and rich in omega-3 fats. These findings do not add much to my knowledge base.
The largest estimated mortality was associated with high sodium intakes. Increased sodium is associated with increased BP, and hypertension is a significant risk factor for both CHD and stroke. In people age 65 or older, sodium was shown to be the leading estimated factor for cardiometabolic mortality. We know that the elderly, black individuals and individuals with comorbidities are more sodium-sensitive.
These findings are consistent with prior U.S. analyses of dietary factors associated with cardiometabolic mortality.
The findings in this JAMA study confirm what we have been telling patients all along about benefits of a heart-healthy dietary pattern. The 2013 American College of Cardiology/American Heart Association guidelines addressed the concept of a healthy dietary pattern as opposed to the effects of individual dietary factors and gave high ratings to the Dietary Approaches to Stop Hypertension (DASH) diet.
Men often have unhealthier dietary habits compared with women because women in general are more concerned about their weight, body image and overall health compared with men, and therefore will lead a healthier lifestyle. Women are more often dissatisfied with their appearance compared with men.
In regards to the decline of diet-associated deaths from 2002 to 2012, Table 1 featured in the study shows improvement in diet over this time period. There were increases in consumption of fruits, vegetables, nuts and seeds, whole grains and a substitution of polyunsaturated fatty acids for saturated fats. There was also a decreased consumption of red meat and sugar-sweetened beverages.
Mexico implemented a beverage tax on sugar-sweetened beverages and noted a decline in consumption, and I would hope that would be the case if a similar tax was implemented in U.S. cities. Possibly as a result of this tax, sugar-sweetened beverages will be less available in the schools where we see a high consumption.
“[Sugar-sweetened beverages] are the single largest source of added sugar and the top source of energy intake in the U.S. diet” (Hu FB. Obes Rev. 2013;doi:10.1111/obr.12040). Findings have consistently shown a significant association between sugar-sweetened beverage consumption and long-term weight gain and risk for type 2 diabetes. Soft drink intake is also associated with lower intakes of milk, calcium and other nutrients.
Micha and colleagues wrote that “Positive messaging to patients, the public and industry can emphasize maximizing the good (rather than simply reducing the harmful) food choices and products.”
Although difficult to do, more outcome studies following public policy interventions to ban trans fats, reduce sodium in processed and prepared foods, and now sweetened beverage taxes are needed.
In the editorial accompanying the JAMA article, Noel Mueller, PhD, MPH, and Lawrence Appel, MD, MPH, encourage public policies that affect the quality of the diet, not just the quantity, and the issues of access and cost of healthier foods, especially among low-income populations (Mueller N, Appel L. JAMA. 2017;doi:10.1001/jama.2017.0946).
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Men often have unhealthier dietary habits compared with women because of the way men and women are socialized differently with respect to food, even starting at young ages.
Our society influences us differently with respect to food, and that probably persists into adulthood.
Between 2002 and 2012, the study showed that the cardiometabolic death rate decreased by about a quarter. At the same time, the researchers saw improvements in national intake of some factors, including polyunsaturated fats, nuts and seeds, and they saw a reduction in sugar-sweetened beverages, increases in whole grains and fruits. Since these dietary factors are associated with cardiometabolic deaths, the improvements in those dietary intakes were associated with the improvement in cardiometabolic death.
These changes in the diet are related to a number of influences. Certainly, there has been a lot of focus on promoting the value of the DASH diet and the Mediterranean diet, which is a very similar diet, so public knowledge of these diets is greater. There has also been a lot of media attention to healthy diet over the years, and it looks like these influences are leading to at least some improvements in our diet.
Some U.S. cities are already moving to have local taxes on sugar-sweetened beverages. The list of cities that have gone in that direction is growing: Berkeley, California; Philadelphia; San Francisco; Oakland, California; Boulder, Colorado; Cook County, Illinois, where Chicago is located; and Seattle. The primary purpose is trying to address childhood obesity and obesity in general. The number of cities adopting these measures is growing. I can’t see the future, but one could speculate it will continue to grow.
We know a lot about what works to prevent heart disease and diabetes. Now what we need is research on how to create sustainable change in diet at the individual and community levels, including changes that work sites, schools, restaurants, grocery stores and other community organizations can make in the food environment that can lead to improved diet. This can include research on how agriculture policies can best promote national and global food security, while also promoting agribusiness productivity and human health.
This is an NHLBI-funded research study, and it reinforces the message that we know a lot about a healthy diet. A healthy diet is composed of real food, mostly plants, and is lower in salts, sweets, processed meats and processed foods than most Americans currently eat. We can continue to improve our health by eating better. We should also remember to move more, avoid tobacco products and follow our doctors’ advice on other ways to reduce our risks for heart disease.
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The JAMA study is important because it reminds us how much impact lifestyle choices have on our health. CVD is the most common cause of death in our country. Some of an individual's risk is genetic, related to a family history that cannot be controlled. However, part of an individual's future risk for MI and stroke can be controlled.
As a society, we often rely on medicine to prevent disease. However, lifestyle also has a strong and complementary role in preventing disease. Heart-healthy lifestyle includes exercise programs and appropriate diets. This study emphasizes how important diet can be in avoiding medical problems. Healthy diet does not just involve avoiding bad foods, but ensuring an adequate intake of healthy foods. This has been a strong component of our dietary counseling for years, but is missing from some fad diets.
While the current study does not reshape our knowledge base, and while its details are based on complex models that can be the topic of many discussions, the general emphasis on increasing the intake of beneficial foods to remain healthy provides an important focus and increased awareness.