"Keep sitting" is a health problem and has a high risk of cancer death

A study investigating the relationship between sitting time (sitting time) and cancer deaths found that the longer the total sitting time per day, the higher the risk of cancer death. However, it has also been shown that reducing sitting time and exercising instead may reduce risk.

Objectively measure "sitting time" instead of self-reporting

Previous studies have shown that sedentary life increases the risk of all-cause mortality (death from all causes) and death from cardiovascular disease (myocardial infarction and stroke), in 2015. Also reported a relationship between sitting time and cancer mortality risk. However, in all studies, sitting time was self-reported and not objectively measured. Also, the effects of exercise during non-sitting hours were not considered.

Therefore, researchers at the University of Texas MD Anderson Cancer Center in the United States have found that the total sitting time objectively measured using an accelerometer and the time spent sitting without interruption (sitting duration) are for middle-aged and elderly people. I decided to investigate the effect on the risk of death. We also looked at how reducing sitting time and exercising instead would affect the risk of cancer death.

From 2003 to 2007, we registered more than 30,000 Americans (whites and blacks) over the age of 45 in the United States. Patients who were being treated for cancer at that time were excluded. We conducted an accelerometer survey of these people from May 12, 2009 to December 31, 2012. I asked him to wear an accelerometer on his waist for seven consecutive days while he was awake.

Based on the recorded accelerometer counts, the physical activity level was determined as follows. 0-49 counts / minute: sitting, 50-1064 counts / minute: light exercise, 1065 counts / minute or more: medium to high intensity exercise

We analyzed 8002 people (mean age 69.8 years, 45.8% male) who had accelerometers for more than 10 hours a day for more than 4 days and had follow-up data on death. The average follow-up period was 5.3 years, during which 268 (3.3%) died of cancer.

13 hours of sitting time per day for groups who died of cancer

Comparing the group of people who died of cancer to the group of people who did not, the group who died of cancer was older, more male, more smokers, and had a history of coronary artery disease (myocardial infarction or angina). There were many patients, and the total sitting time was long. The average total sitting time per day was 777.3 minutes for those who died of cancer, about 35 minutes longer than 741.8 minutes for those who did not. The average sitting duration (time to sit without interruption) was 14.0 minutes and 11.4 minutes. Light exercise was 154.8 minutes and 189.2 minutes per day, and medium to high intensity exercise was 7.9 minutes and 13.4 minutes, both of which were lower in the cancer-dead group (all). There is a statistically significant difference).

The person with the shortest to the longest sitting time is arranged in a row and divided into three equal parts, with the lowest tertile group (2667 people) as the reference group and the second tertile group (2668 people), the highest. We compared the risk of cancer death in the tertile group (2667 people).

Age, race, gender, area of ​​residence, academic background, season with accelerometer, smoking habits, drinking habits, BMI (body mass index), diabetes, hypertension, dyslipidemia, coronary artery disease history, stroke history, medium to high Analysis with intense exercise in mind revealed a significantly higher risk of cancer mortality in the second and highest tertiles than in the lowest tertiles.

Since the analysis also takes into account medium to high intensity exercise time, there is a significant relationship between sitting time and cancer mortality risk, regardless of whether or not medium to high intensity exercise is routinely performed. It was shown to be.

Similarly, we investigated the relationship between sitting duration and cancer mortality risk. The longer the sitting duration, the higher the risk of cancer death tended to be, but no significant relationship was shown.

Next, considering the total sitting time as a continuous variable, the relationship with cancer death was examined, and it was suggested that the risk of cancer death increased by 16% for each 1-hour extension of sitting time. ..

The authors also estimated the benefits of replacing sitting time with exercise. It is estimated that reducing sitting time by 30 minutes and doing light exercise during that time reduces the risk of cancer death by 8%, and replacing it with 30 minutes of medium to high intensity exercise reduces the risk of cancer death by 31%. I did.