Dust off your FitBit: a new study found a correlation between higher daily step count and lower all-cause mortality—including cancer mortality. However, step intensity did not appear to be related to mortality.
U.S. adults aged at least 40 years were identified from the National Health and Nutrition Examination Survey. Participants wore an accelerometer for up to one week between 2003 and 2006 and were followed for mortality through December 2015. Daily step counts measured by the accelerometer and three-step intensity measures—extended bout cadence, peak 30-minute cadence, and peak one-minute cadence (steps/minute)—were recorded. All-cause mortality was the main outcome. Additional outcomes included mortality due to cardiovascular disease and cancer.
Final analysis included 4,840 patients (mean age, 56.8 years; 54% [n=2,435] were female; 36% [n=1,732] were obese). Patients wore the accelerometers for a mean 5.7 days and a mean 14.4 hours per day. Patients took a mean 9,124 steps per day.
Over a mean 10.1 years of follow-up, 1,165 deaths occurred, of which 406 were cardiovascular disease-related and 283 were cancer-related. In unadjusted analyses, the incidence density for all-cause mortality was 76.7 per 1,000 person-years (419 deaths) for patients who took less than 4,000 steps per day (n=655), 21.4 per 1,000 person-years (488 deaths) for patients who took 4,000 to 7,999 steps per day (n=1,727), 6.9 per 1,000 person-years (176 deaths) for patients who took 8,000 to 11,999 steps per day (n=1,539), and 4.8 per 1,000 person-years (82 deaths) for patients who took at least 12,00 steps per day (n=919). Patients who took 8,000 steps per day, compared to those taking 4,000, had significantly lower all-cause mortality (hazard ratio [HR]=0.49; 95% confidence interval [CI], 0.44 to 0.55), as did patients taking 12,000 steps (HR=0.35; 95% CI, 0.28 to 0.45).
“Unadjusted incidence density for all-cause mortality by peak 30 cadence was 32.9 per 1000 person-years (406 deaths) for the 1080 individuals who took 18.5 to 56.0 steps per minute; 12.6 per 1000 person-years (207 deaths) for the 1153 individuals who took 56.1 to 69.2 steps per minute; 6.8 per 1000 person-years (124 deaths) for the 1074 individuals who took 69.3 to 82.8 steps per minute; and 5.3 per 1000 person-years (108 deaths) for the 1037 individuals who took 82.9 to 149.5 steps per minute,” the study authors reported.
When adjusting for total daily steps, there was no correlation between greater step intensity and lower mortality.
The study’s findings were reported in JAMA.
