1.4: Behind the Soundbite

We often get health information as soundbites—a catchy sentence or two (scary ones work best). News articles tell us more, but many of us only read the headlines. Here’s a soundbite that alarms an 80-year-old man: Life expectancy in the U.S. has risen to 79. He feels he’s due to die any minute. What didn’t fit into the soundbite was that men his age live to an average of 88 (Figure 1.3.3). If he lives to 85, the average age of death goes up to 91 because those who died between 80 and 85 drop out of the average. (The biggest gains in life expectancy come from saving the lives of infants, just as an average test score of 70% gets the biggest boost when those scoring near zero do a lot better.)

Here’s a soundbite that scared women: Women in the San Francisco Bay Area have the highest rate of breast cancer. Unsaid was that they didn’t have the highest death rate from breast cancer, but the highest diagnosis rate (and not by much), which was fully explained by more screening and known risk factors (e.g., having children at an older age, menopausal hormone replacement therapy). Also, as will be discussed in Chapter 12, diagnosis rates

Figure \(\PageIndex{4}\): Age-adjusted death rates for heart disease and cancer (1950-2019)

are tracked only in select geographical regions, not the entire U.S. population. The San Francisco Bay Area is one of those regions, so highest here means that was the highest among the select regions only.

The age-adjusted death rate for heart disease has been falling dramatically (Figure 1.4.4). So here’s a possible future soundbite that would scare us all: Cancer is now our leading cause of death.* This wouldn’t be cause for alarm if cancer became #1 by default from a falling death rate from heart disease, but this added information would dilute the soundbite’s impact.

Most of us hear about the latest scientific findings via soundbites. This can cause confusion and anxiety, especially when the soundbites conflict. Soundbites put studies on equal footing although, as will be discussed in the next chapter, studies differ by a lot in research design, validity, and in how the results relate to us personally.

Scientists critically examine the details behind the soundbites. Even when a study passes muster, it’s just a small addition to the big picture—the normal way scientific information is gathered. Nonscientists, too, can assess new information more objectively if they know the criteria for good experimental design and valid conclusions. Also, we can assess new information more calmly, knowing that scientific knowledge comes in bits

Figure \(\PageIndex{5}\): “Rectangularizing” the survival curve

and pieces, some of which are discarded as results of new studies trickle in.

We’re bombarded with nutrition and health information from diverse sources (ads, food labels, books, social media, websites, etc.), not all of which are based on scientific evidence. Often, the information is tied in with marketing, not only of food products and dietary supplements, but of newsletters and magazines wanting subscribers and of organizations seeking donations. These— together with a steady stream of soundbites that sometimes seem to conflict—often leave us bewildered.

The chapters that follow explain the basics of how scientific information is gathered and how the body works. This knowledge will make us better equipped to sort out scientifically based advice and use it to improve our health. Even small changes in dietary and living habits can dramatically prevent or delay our most common diseases. Heart attacks, for example, usually result from narrowing and blockage of arteries that supply blood to the heart. Because the narrowing occurs gradually over many years, taking measures to slow this process, even slightly, can delay or prevent a heart attack.

Scientists speak of the rectangularization of the survival curve (pushing the survival curve up and out to make Figure 1.5 a rectangle, in which case we’d all survive to old age. They speak of pushing a disease out of the life span—delaying disease until after age 100 or so. Scientists also speak of compressing the period of morbidity— shortening the time we’re ill before we die. In layman’s terms, we want to live life to its full measure in good health.

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*As seen by the trajectory of heart disease in Figure 1.4.4, it was a surprise that heart disease did not fall below cancer in 2016, to make cancer our leading cause of death. Possible reasons include the rise in diabetes (Figure 1.2.2) that increases the risk of heart disease, and less smoking resulting in less lung cancer.