Lifestyle+ — 31

Virtually everything discussed in this chapter has a connection with social determinants of health. A pivotal paper in 2017 on determinants of premature mortality among 1.7 million people provided unequivocal support for the importance of socioeconomic status, an independent risk factor. Socioeconomic status determines one’s likelihood of good health as much as cigarette smoking, high alcohol intake, hypertension, type 2 diabetes, or physical inactivity. More unprocessed food in diet, poor sleep, more air pollution, and less physical activity are disproportionally found in people with lower socioeconomic status. The first systematic review on the association of education and adult mortality showed a dose-response with a reduction of mortality risk of about 2 percent for every additional year of education. If we are to see a population-wide improvement in health span, the marked inequities must be reduced. Food deserts are real. More than sixty-five hundred of them are in the United States. Places where it is difficult to get healthy food, populated by a total of twenty-four million people. One study used GPS tracking for ninety-four million visits to 359,000 food retailers over two years. Most people travel beyond their neighborhood to buy food, an average of 3.7 miles. Travel to retailers that sold healthy food had a stronger association with the prevalence of obesity and cardiometabolic conditions than the percentage of retailers in a local area. Food insecurity, affecting more than fifty million Americans, has been linked to all-cause premature deaths in a study of over fifty-seven thousand adults, with about a 50 percent increase compared with people with full food security. Food-as-medicine programs to address food deserts and food insecurity have attracted considerable attention, but randomized trials have not yet borne out improvement in clinical outcomes. So much more dedicated efforts are required to combat inequities so that improvements in health span that are occurring will not be restricted to people of high socioeconomic status.

My expanded view of lifestyle makes a measurable difference to human health span. According to a modeling study for Americans, a sustained change in a typical Western to an optimal diet as we’ve reviewed, starting at age twenty years, would increase lifespan by more than ten years. Similarly, a UK Biobank modeling study for people aged forty calculated that adopting a healthy diet led to a nine-year increase in life expectancy. Among fourteen thousand Americans, those who didn’t smoke, were not obese, and drank alcohol in moderation lived an average of seven years longer than their peers without this trio of lifestyle factors.