What really lowers your risk of heart disease?

The nine factors

INTERHEART compared 15,152 people who had a first heart attack with 14,820 controls in 52 countries. Eight modifiable factors (smoking, the apoB/apoA1 blood-fat ratio, high blood pressure, diabetes, abdominal obesity, psychosocial stress, low fruit-and-vegetable intake and inactivity), plus alcohol intake, together accounted for 90 percent of the population-attributable risk in men and 94 percent in women, and the associations held in every region¹.

Food, with the trials behind it

• Mediterranean diet. In PREDIMED, 7,447 adults at high risk who were given extra-virgin olive oil or mixed nuts had about 30 percent fewer major events (heart attack, stroke or cardiovascular death) over 4.8 years than adults advised to cut fat². After a first heart attack, the Lyon Diet Heart trial's Mediterranean-style diet also cut cardiac death and repeat infarction (14 events versus 44)⁴. See Mediterranean diet.
• DASH-style eating. Plenty of fruit, vegetables and low-fat dairy lowered systolic pressure 5.5 mm Hg more than a low-fruit, low-vegetable control diet in 459 adults, and 11.4 mm Hg more in those with hypertension⁵. See blood pressure.

Movement, tobacco and sleep

Going from inactive to 150 minutes a week of moderate activity was linked to 17 percent lower cardiovascular disease incidence and 23 percent lower cardiovascular mortality, with the biggest gain from the first small amounts⁶. Smokers lose at least a decade of life, and quitting before 40 cut the added risk of death by about 90 percent⁷. The American Heart Association's Life's Essential 8 score puts sleep alongside diet, activity, nicotine, weight, blood fats, blood sugar and blood pressure⁸.

Genes are not destiny

Among 55,685 people, a favorable lifestyle went with a 46 percent lower risk of coronary events even in those at high genetic risk⁹.

When medicine is the right tool

Lifestyle and medicine are partners. Aiming for a systolic pressure under 120 mm Hg instead of 140 cut major events by 25 percent in 9,361 high-risk adults without diabetes, though low blood pressure and kidney problems were more common³. Statins lower the risk of heart attack and stroke in proportion to the fall in LDL¹⁰; see what lowers cholesterol. Even on the Mediterranean diet, cholesterol and blood pressure still predicted a second event in the Lyon trial⁴.

Go deeper: atherosclerosis, triglycerides and lipoprotein(a).

INTERHEART

Smoking (odds ratio 2.87 for current versus never; population-attributable risk 35.7 percent), a raised apoB/apoA1 ratio (3.25, top versus bottom fifth; 49.2 percent), hypertension (1.91; 17.9 percent), diabetes (2.37; 9.9 percent), abdominal obesity (20.1 percent), psychosocial factors (2.67; 32.5 percent), lacking daily fruit and vegetables (0.70 for having them; 13.7 percent) and regular exercise (0.86; 12.2 percent) were all linked to infarction in men and women, young and old. Regular alcohol was modestly inversely associated (0.91), which observational data cannot separate from other habits. The case-control design relies on recall and shows association, not proof of cause¹.

The diet trials

PREDIMED randomized 7,447 Spanish adults aged 55 to 80 at high cardiovascular risk to a Mediterranean diet with extra-virgin olive oil, a Mediterranean diet with mixed nuts, or advice to cut dietary fat. Over a median 4.8 years, 288 had a major event: 96 (3.8 percent), 83 (3.4 percent) and 109 (4.4 percent). Adjusted hazard ratios were 0.69 (95% CI 0.53 to 0.91) for olive oil and 0.72 (0.54 to 0.95) for nuts². This is a corrected analysis: the investigators withdrew their 2013 report after finding protocol deviations, including household members enrolled without randomization and some participants at one of 11 sites not randomized. Results were similar after omitting 1,588 participants whose assignment was known or suspected to depart from protocol².

The Lyon Diet Heart Study randomized survivors of a first heart attack to a Mediterranean-type or a prudent Western-type diet. Over a mean 46 months, cardiac death plus nonfatal infarction occurred 14 times versus 44, with adjusted risk ratios of 0.28 to 0.53 across outcome definitions. Cholesterol, blood pressure, white-cell count and aspirin use still predicted recurrence, so the authors advised pairing diet with other, possibly drug, risk-factor treatment⁴. DASH was a feeding trial: 459 adults ate a control diet, a fruit-and-vegetable diet or a combination diet for eight weeks, with sodium and weight held constant. The combination diet lowered pressure 5.5/3.0 mm Hg more than control, and 11.4/5.5 mm Hg more in the 133 people with hypertension⁵.

Pressure, activity and tobacco

SPRINT randomized 9,361 adults with systolic pressure of 130 mm Hg or higher, extra cardiovascular risk and no diabetes to a target under 120 or under 140. It stopped early at a median 3.26 years: the primary outcome occurred at 1.65 versus 2.19 percent a year (hazard ratio 0.75, 0.64 to 0.89) and all-cause death was lower (0.73, 0.60 to 0.90), but serious hypotension, fainting, electrolyte problems and kidney injury were more frequent³. A meta-analysis of 36 studies (3,439,874 participants) put the move from inactive to 150 minutes a week at relative risks of 0.83 for cardiovascular disease incidence and 0.77 for mortality⁶. In a US survey of 202,248 adults, current smokers died at about three times the rate of never-smokers, and quitting at 25 to 34, 35 to 44 or 45 to 54 gained about 10, 9 and 6 years of life⁷.

Genes, medicines and what not to take

In four studies of 55,685 people, high genetic risk raised coronary events (hazard ratio 1.91 for top versus bottom fifth). Among those at high genetic risk, a favorable lifestyle (at least three of: no smoking, no obesity, regular activity, healthy diet) went with a 46 percent lower risk (0.54, 0.47 to 0.63); in one cohort the 10-year incidence fell from 10.7 to 5.1 percent⁹. Pooled statin trials found a 22 percent fall in major vascular events per 1 mmol/L fall in LDL (rate ratio 0.78)¹⁰.

In a registry of 1,521 people discharged on aspirin, a beta-blocker and a statin, the 184 who stopped all three within a month had lower one-year survival than those who kept taking at least one (88.5 versus 97.7 percent; adjusted hazard ratio 3.81, 1.88 to 7.72), though people who stop medicines may differ in other ways¹¹.

Null results and limits

More is not always better. In ASPREE, 19,114 healthy adults aged 70 or older took aspirin 100 mg or placebo for a median 4.7 years. Cardiovascular events were 10.7 versus 11.3 per 1,000 person-years (0.95, 0.83 to 1.08), while major bleeding was 8.6 versus 6.2 (1.38, 1.18 to 1.62)¹². Life's Essential 8 is a scoring framework, with 0 to 100 points for each of eight metrics, not a trial⁸. The exercise and smoking figures come from population studies, so they show association rather than proof, and PREDIMED's comparison group was low-fat advice rather than a usual diet.

Bottom line

Confidence is fairly high (4 of 5). Randomized trials support Mediterranean eating and blood-pressure treatment^2,3, large cohorts support movement and not smoking^6,7, and medicines such as statins add protection when risk is high¹⁰. Diet trials with heart-attack endpoints are few, so treat food as strong but not fully proven prevention.