With healthcare reform on many people's minds, and awareness of the rising and overwhelming costs of chronic disease, I want to bring to your attention two recent articles in the Journal of the American Medical Association (JAMA), both of which study the effects of lifestyle factors on two all-too-common chronic illnesses in two different populations.
The first study by Forman et al looks at the relationship between six modifiable lifestyle factors and the lifetime risk of heart failure. Heart failure is a very serious situation in which the heart structure or function is impaired, and cannot keep up with the body's blood supply needs. The most common causes of heart failure in the U.S. are coronary artery disease and hypertension.
The study included 20,900 physicians, all apparently healthy, and with an average age of 53.6 years at the baseline. The six healthy lifestyle factors were: Normal weight (body mass index, or BMI of 25 as the cutting point), not smoking, exercise (fitness in this study defined as exercising five or more times a week), moderate alcohol consumption (5-12 drinks a week), fruit and vegetable consumption (more than four servings a day) and breakfast cereal consumption (more than one serving a week).
The group was followed for an average of 22.4 years. During that time 1,200 men developed heart failure. The lifetime risk of developing heart failure in the general population is 20 percent; overall, it was 13.8 percent for this group of physicians.
Here's what the study found:
• Each healthy lifestyle behavior was individually and jointly associated with lower lifetime risk of heart failure; in other words, there was a clear inverse relation between the number of healthy lifestyle factors and the risk of heart failure.
• Men who adhered to none of the healthy lifestyle factors had a lifetime risk of about 21 percent.
• Men who adhered to four or more of the healthy lifestyle factors had a lifetime risk of about 10 percent.
• When looking at only three of the healthy lifestyle factors-normal weight, not smoking and exercise-the lifestyle factors' protection persisted.
These numbers show quite nicely that having a higher education is not enough to lower the risk of heart failure; the physicians who didn't adhere to any healthy habits had as high a risk as that of the general population. It's probably the physicians' healthier habits and modifiable lifestyle factors that lower their overall risk of this chronic disease.
Not to neglect us women, the second study by Djoussé et al was conducted in more than 80,000 female nurses, aged 27-44 years, who were free of hypertension at the baseline, and were followed over 14 years, looking at the association between diet and lifestyle.
The healthy lifestyle factors in this study were:
• Normal weight (BMI of less than 25).
• A healthy diet: This was assessed by a looking at the foods prescribed in the Dietary Approaches to Stop Hypertension (DASH) trial. The DASH score is based on a high intake of fruit, veggies, nuts, legumes, low-fat dairy, whole grains, and low intake of red and processed meats, sweetened beverages and sodium.
• Daily vigorous exercise, lasting an average of 30 minutes a day.
• Modest alcohol intake: This amounts to intake of more than zero, but less than one alcoholic beverage a day-which seem to be protective for hypertension. Larger amounts of alcohol are associated with a higher risk of hypertension.
• Infrequent use of non-narcotic analgesics: Non-narcotic analgesic drugs (Tylenol, aspirin, non-steroidal anti-inflammatory drugs) have been associated with hypertension.
• Folic acid supplementation: Studies show women with low dietary folic acid intake are at higher risk of hypertension and benefit from supplementation.
The results involve some pretty complicated statistics, but here are the main findings: • During follow-up, 12,319, or 15 percent, of the women developed hypertension.
• The strongest risk factor was overweight or obesity: Obese women had a risk five times higher than that of women with a BMI of under 23, and 40 percent of new hypertension cases can be hypothetically attributed to overweight or obesity.
• The other five healthy lifestyle variables were also associated with lower risk of hypertension, but are less influential than overweight and obesity.
• Women who had several healthy lifestyle factors had progressively lower risk: A combination of normal weight (BMI less than 25), exercise and a good diet reduced risk by about 50 percent!
For those of us that fear that family history puts us at a high risk no matter how well we take care of ourselves, this study repeated the analysis after taking into account a family history of hypertension, and showed that women with a family history had almost as low a risk as those without it, when they adhered to a combination of low-risk behaviors. In other words, family history is much less of a risk than is being overweight.
The results of these studies join a large body of evidence-some of which I've mentioned in previous posts -supporting the conviction that there's a lot we can do to keep healthy.
In a fascinating editorial accompanying these studies Mayo Clinic researcher Véronique L. Roger discussed, among other things, the role of public health policy on lifestyle. The argument she makes is that a healthy lifestyle can't be just an individual choice-there needs to be a social climate that enables people to make healthy choices more easily, and lifestyle is an interplay between individuals and the society they live in. Examples given in the editorial are the effects of smoke-free workplaces and interventions eliminating trans-fats from restaurants have on the public's cardiovascular health, regardless of individual initiatives to choose a healthier lifestyle.
"At this point, the national cost of treating cardiovascular diseases cannot be sustained, and prevention is urgent. Because prevention can benefit from policies aimed at creating a healthier environment, this approach must be expanded, with obvious targets being school-based meals provided to children, which still do not meet national dietary recommendations for good health, and the conceptualization and restructuring of the environment to promote physical activity. These and other public health measures should be envisioned as complementary and synergistic with clinical care, because unhealthy societal choices that lead to illness result in unsustainable strain on health care systems."
I, for one, really would like to see steps taken to ensure healthy choices are easier to make, and aren't prohibitively expensive in a way that makes them accessible only to those with both will and means.
Sure enough, when unhealthy food is cheap (and subsidized), and healthy foods-such as fruits and vegetables-are expensive, and one needs a gym membership to keep fit, it's going to take a lot of individual determination to acquire the healthy habits and healthy weight we need to avoid cardiovascular disease.
I wonder what you think about government's role in ensuring that a healthy lifestyle is an easier choice for everyone.