In the modern world, there have been steady increases in life expectancy. It has more than doubled in the last two centuries — that is, until now. As widely reported, for the third year in a row, the U.S. death rate rose last year.

Until recently, the big debate for demographers had to do with what the ceiling for human longevity might be. They, along with the health community, are now forced to answer a very different question: Why has life expectancy been so suddenly thrown into reverse?

The lingering issue of obesity and the increasing prevalence of suicide, depression and drug abuse clearly play a role when considering preventable causes of death, as do diseases of the heart, cancers, stroke, chronic lower respiratory diseases and unintentional injuries. According to the World Health Organization, in 2014, these causes accounted for 63% of deaths. According to the Centers for Disease Control and Prevention, in the United States, cigarette smoking remains the leading cause of preventable disease and death, accounting for more than 480,000 deaths every year — about 1 in 5 deaths in this country.

These trends are happening at the same time that the potential for a long and relatively healthy life have never been greater. Since the early 1970s, we have seen a rapid increase in the number of very old people in this country. We are talking about people living to 100, 110 or even longer.

They are the “supercentenarians,” and I have written about them in the past. As noted in a recent edition of The Conversation, this select group is more than simply durable. Perhaps because of their inherent resilience and particular physiology, they are best able to benefit from the improvements in living conditions and technology. What they demonstrate is that it may be possible to lengthen lifespans further if improvements in health at the highest ages can be realized. With the proper commitment and with changes, there is no reason the human longevity revolution cannot continue. Upward lifespan trends are not a given; we have work to do to achieve them.

According to a new study led by the Harvard T.H. Chan School of Public Health and published in the journal Circulation, a worldwide effort to lower people’s blood pressure, cut their sodium intake and eliminate trans fat from their diet could dramatically reduce the incidence of premature death from cardiovascular disease in a little over a quarter-century. They estimated that scaling up treatment of high blood pressure to 70% of the world’s population could extend the lives of 39.4 million people. Cutting sodium intake by 30% could stave off another 40 million deaths and could also help decrease high blood pressure, a major risk factor for cardiovascular disease. Eliminating trans fat from food products could prevent 14.8 million early deaths.

The researchers also acknowledged that scaling up such interventions would be a “huge challenge,” requiring countries to commit additional resources to boost health care capacity and quality.

At the same time, previous analyses have shown that the interventions are achievable and affordable. For example, a Kaiser Permanente program in Northern California increased control of hypertension to 90% among thousands of the health system’s patients between 2001 and 2013, using strategies such as improved treatment protocols, patient-friendly services and health care information systems that facilitate tracking people with hypertension.

In another recent study published in the journal Lancet, poor diets are deemed responsible for more deaths around the world than any other risk factor, including cigarette smoking. For the study, researchers looked at people’s eating habits across 195 countries in estimating how much poor diets contribute to mortality. According to their findings, 11 million people die each year around the world at least in part because of certain foods or lack thereof.

Researchers found that the problem is not only what people are eating but also what they are not eating. The study estimated that, globally, 3 million deaths can be attributed to too much sodium. Another 3 million deaths were attributed to a lack of adequate whole grains, while another 2 million deaths were attributed to a lack of adequate access to fruit. Physical inactivity and various environmental, economic and social circumstances were also major contributing factors.

The study findings reaffirmed what health professionals have been teaching for years: A balanced diet is important for a long healthy life. Hopefully, news of the study’s results will help urge people to try to eat better and will help urge policymakers to create and promote policies that aim to increase consumption of healthful foods.

It should be no surprise to learn that the work lives of Americans are increasingly unpredictable and hectic. Another recent study of mothers with children found taking time to cook for their families to be a luxury they just do not have. A 2015 study found that 17% of people have jobs with irregular schedules, a disproportionate number of them low-income workers. Having little control over time makes it difficult for families to plan their meals in advance or even to know who will be there for dinner. These nonstandard work schedules are also associated with an increased risk of health problems.

What this study illustrates is that today’s demanding workplaces, combined with the cultural expectation to parent, places a huge burden on families today. We need to do a better job of investing and supporting these families and their health.

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