Study: Effects of walking on cancer and cardiovascular mortality

reference

Del Pozo Cruz B, Ahmadi MN, Lee IM, Stamatakis E. Prospective associations of daily step count and intensity with cancer and cardiovascular disease incidence and mortality and all-cause mortality.JAMA Intern Med. 2022;182(11):1139-1148.

Study objective

To examine the associations between steps (total number of steps and type of steps) and mortality (overall cause, cancer and cardiovascular disease (CVD)) and incidence (cancer and CVD).

Key to take away

People who take up to 10,000 steps per day reduce the risk of death (from cancer, cardiovascular disease or other causes) as well as the risk of developing cancer and cardiovascular disease, with periods of higher cadence providing additional benefit

design

Observational, prospective cohort study

Participant

This large study involved 78,500 participants. The median age was 61 years and the vast majority (97%) were white. 55% of the sample were women.

The researchers drew participants from the larger UK Biobank study (2013-2015). They mailed accelerometers to those who accepted the invitation to participate and asked them to wear an Axivity AX3 accelerometer 24 hours a day for seven days.

Inclusion criteria:

• Es wurden Teilnehmer mit gültigen Daten einbezogen. Dies ist definiert als:

• Mindestens 3 „gültige Überwachungstage“, also 16 Stunden Tragezeit oder mehr pro Tag. Tage müssen nicht aufeinanderfolgend sein;

• Einbeziehung von 1 Wochenendtag;

• Einbeziehung von Schlafphasen (keine Angabe der Dauer).

Exclusion criteria:

Participants were excluded if:

• Sie gaben selbst an, dass ihr Gesundheitszustand schlecht sei;

• Sie hatten aktiven Krebs oder eine Herz-Kreislauf-Erkrankung;

• Für alle Kovariaten (Alter, Raucherstatus, Bildung und andere) fehlten Daten.

In general, participants in this study were healthier and of higher socioeconomic status than patients in the larger UK Biobank study.

Evaluated study parameters

This study went beyond just counting steps; It also assessed the types of steps participants took (random or goal-directed), their intensity, and assessed whether different health outcomes were associated with each type of step.

Primary exposures were:

• Tägliche Schrittzahlen (mittlere Anzahl der Schritte über gültige Überwachungstage)

• Arten von Schritten:
  • Zufällige Schritte (definiert als weniger als 40 Schritte pro Minute)
  • Zielgerichtete Schritte (mehr als 40 Schritte/Minute)
• Schrittfrequenz:
  • Maximale 30-Minuten-Trittfrequenz (definiert als die 30 nicht aufeinanderfolgenden Minuten pro Tag mit der höchsten Schrittzahl)

Investigators obtained participant health data from national databases in England, Wales and Scotland (up to October 2021) to identify:

• Todesfälle und Diagnosen von Krebs (Blase, Brust, Dickdarm, Endometrium, Speiseröhre, Magen, Kopf und Hals, Niere, Leber, Lunge, myeloische Leukämie, Myelom und Rektum)

• Todesfälle durch und Diagnosen von Herz-Kreislauf-Erkrankungen (koronare Herzkrankheit, Schlaganfall, Herzinsuffizienz)

• Krankenhausaufenthalte aus allen Gründen

• Todesfälle aus allen anderen Gründen

Primary and secondary diagnoses were included. Named cancer sites are most commonly associated with low levels of physical activity.¹

Primary outcome

Association between cancer and cardiovascular disease and all-cause mortality in relation to step number and step intensity in the study population

Key findings

The median follow-up time was 7.0 years (53,196 person-years), and during this period there were 2,179 deaths, including 1,324 from cancer and 664 from cardiovascular disease. Cardiovascular disease occurred in 10,245 people and cancer in 2,813.

All results listed below were statistically significant.

Daily step count:

For each additional 2,000 step increase, the risk of all-cause mortality decreased by 8%, cancer mortality by 11%, and CVD mortality by 10%.

Note: Personal communication with the corresponding author confirmed several typos. All values ​​in the Results section should be preceded by a minus sign (“–”).

Random steps (<40 steps/minute):

For each additional 10% increase, the risk of all-cause, cancer, and CVD mortality decreased by 6%, 6%, and 10%, respectively.

Targeted steps (≥40 steps/minute):

For each additional 10% increase, the risk of all-cause mortality, cancer, and cardiovascular mortality decreased by 7%, 8%, and 10%, respectively.

Maximum 30-minute cadence (the 30 daily minutes with the highest step count):

For each additional 10% increase, the risk of all-cause, cancer, and cardiovascular mortality decreased by 8%, 9%, and 14%, respectively.

The incidence of cancer and cardiovascular disease was reduced by similar amounts, 4 to 7%.

transparency

This work was supported by a research grant from the National Health and Medical Research Council and the University of Southern Denmark.

Implications and limitations for practice

The concept of walking 10,000 steps per day to achieve better health is believed to have been popularized by a Japanese pedometer manufacturer in the 1960s.²The study reviewed here by Del Pozo Cruz et al. examined whether this comfortable number is really the best goal for everyone.

Because 78,500 people were included in the study, the authors were unable to find a minimum threshold for the number of steps associated with a lower risk of mortality and morbidity from cancer, cardiovascular disease and other causes. In other words, even a small amount of exercise reduces the risk of dying or developing cancer or cardiovascular disease.

The number of steps has been evaluated in other studies that appear to reflect the idea that 10,000 may not be the right goal for everyone. Lee et al. studied a slightly older cohort (mean age 72 years versus 61 years in this study) and found that the mortality rate plateaued at around 7,500 steps.³Paluch et al. found that the decline in overall mortality rates was maximal at 6,000 to 8,000 steps in people aged 60 years and at 8,000 to 10,000 steps in people under 60 years old.⁴Higher step counts still seem to be more helpful than lower ones, but perhaps the 10,000 step goal isn't the whole story.

The intensity of the steps we take also seems to play a role.

Before you begin narrowing your patient recommendations, note that Del Pozo Cruz's study found several dose-response relationships. Every 2,000 steps taken by participants resulted in a reduction in the risk of dying from cancer by 11% and from cardiovascular disease by 10%. This reduction in deaths per 2,000 steps held until the magic number of about 10,000 steps.

The intensity of the steps we take also seems to play a role. Higher intensity or “purposeful” steps we take while walking (≥40 steps/minute) are associated with lower risk across all outcomes studied, slightly more so than steps we take when we walk into a room and wonder why we are there (“random” steps at <40 steps/minute). People who averaged a faster pace in their fastest 30 minutes per day also saw greater reductions in the risk of developing cardiovascular disease and cancer, or dying from these or other causes.

The researchers again observed dose-response relationships. For every 10 percent increase in random or targeted steps, the risk of mortality decreased by 6 to 10 percent. A 10% gradual increase in 30-minute cadence was associated with an 8 to 14% lower mortality rate.

Is it possible to taketoo manySteps? The numbers included in this work suggest a U-shaped curve that appears to associate the highest step count (>20,000/day) and the highest 30-minute cadence (>100 steps/min) with less prominent reductions in cardiovascular outcomes, although the differences are not statistically significant. Do we need to tell our patients to stop walking at 10,000 steps? Probably not.

From an opposite perspective, a 2017 study of postmen in Glasgow found that higher step counts (>15,000/day) were associated with fewer metabolic risk factors for cardiovascular disease, although mortality was not assessed.⁵This seems more in line with what we would expect from higher levels of activity.

Additionally, the authors of the paper discussed here cite a “statistical uncertainty” above the 10,000 step threshold, which may be due to there simply being fewer participants in the 10,000+ step club. Future research could clarify whether walking more than 10,000 steps per day is harmful. This paper does not identify a statistically significant hazard.

This study provides some important information to share with our patients. First, any amount of exercise you can do is beneficial. This reminds me of my elderly patients or palliative patients who still move around in their own homes, go up the stairs and do light housework. These patients may find the goal of 10,000 steps daunting and daunting. It's nice to be able to provide evidence that their efforts to keep moving are clearly beneficial.

Second, it seems that more really is better. The fact that the evidence is less certain beyond 10,000 steps could be something of a self-fulfilling prophecy. The popularity of the 10,000 step goal could lead to fewer people exceeding this goal, so we currently have less evidence to support higher step counts. In any case, this paper supports the suggestion of getting as much exercise as possible, at least up to 10,000 steps.

Finally, higher intensity training may be more beneficial. Your mortality and morbidity risks are likely to be reduced more by a brisk walk outside than by strolling from the couch to the fridge between Netflix episodes, even if your step count is similar.

Pedometers are a convenient way for patients to measure their activity and can actually encourage people to move more.⁶In a 2018 Canadian survey, over a quarter of participants owned a wearable fitness tracker.⁷These popular devices allow patients and doctors to work together to set and evaluate exercise goals. Having data to help us choose our exercise goals will make fitness trackers more suitable for everyone.